Supra-condylar humerus fractures (SCHF) are amongst the most common fractures requiring surgical stabilisation in the pediatric age group (1). Closed reduction and percutaneous fixation with Kirschner wires (KW) is currently the standard of care (2). The number of KW used and their configuration has been the subject of much research (3, 4). The failure modes leading to loss of fracture reduction are not clear and have not been quantified. The aim of this study is to compare the mechanical stability of the opt-used configurations for various loading modes and contact interactions at the KW/bone interface.

A Gartland type-III SCHF was introduced to a fourth generation composite saw bone (Sawbones®, Vashon, Washington, USA). The model was CT scanned with a slice spacing of 0.5mm and pixel size 0.3×0.3mm. The CT data set was imported into AmiraDev (AmiraDev 5.2 Visage Imaging, Inc). A uniaxial mechanical test was conducted in order to measure the KW pullout forces from the distal humerus.

A model of the fractured humerus was constructed with the following steps: 1) manual segmentation; 2) surface generation of each fragment, and; 3) automatic volumetric grid generation for each fragment. The fracture was then virtually reduced and KWs were placed at the desired configurations (Fig 1a-b). For each configuration, a separate model was generated. Material properties were assigned to the bone-model elements according to the manufacturer's data sheet; Young's modulus E = 16GPa and E = 150MPa for the cortical and cancellous bone respectively. The KW were assigned a Young's modulus of 200GPa. Each of the models created in Amira was imported to a finite element application (Abaqus 6.9, DS-Simula) for structural analysis. For each of KW configuration four different torque forces load types were simulated (Fig 1c left): 1) a clockwise and counterclockwise torque with a magnitude of 1.5 NM (Newton/Meters); 2) a translational force with a magnitude of 30 N (Newtons) in the direction of the humerus shaft, and; 3) a shear force with a magnitude of 30 N in the direction parallel to the fracture plane. The results were normalised such that the maximum displacement for the crossed pin configuration with a coefficient of friction equal to zero (μ = 0) was used as unity for each load configuration. Similarly, for each of KW configuration four different translational forces load types were simulated (Fig 1c right): 1) a clockwise and counter clock-wise torque with a magnitude of 1.5 NM (Newton/Meters); 2) a translational force with a magnitude of 30N in the direction of the humerus shaft, and; 3) a shear force with a magnitude of 30N in the direction parallel to the fracture plane. The results were normalised as described above.

The common practice for insertion of distal locking screws of intramedullary (IM) nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure to patient and surgical personnel. A new technique is introduced which guides the surgeon by landmarks on the X-ray projection.

18 fresh frozen human below-knee specimens (incl. soft tissue) were used. Each specimen was instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland) and was mounted on an OR-table. Two distal interlocking techniques were performed in random order using a Siemens ARCADIS C-arm system (Siemens AG, Munich, Germany). The newly developed guided technique, guides the surgeon by visible landmarks projected onto the fluoroscopy image. A computer program plans the drilling trajectory by 2D-3D conversion and provides said guiding landmarks for drilling in real-time. No additional tracking or navigation equipment is needed.

All four distal screws (2 mediolateral, 2 anteroposterior) were placed in each procedure. Operating time, number of taken X-rays and radiation time were recorded per procedure and for each single screw.

8 procedures were performed with the freehand technique and 10 with the guided technique. A 58% reduction in number of fluoroscopy shots per screw was found for the guided technique (7.4±3.4 vs. 17.6±10.3; p < 0.001). Total radiation time was 55% lower for the guided technique (17.1 ± 3.7s vs. 37.9 ± 9.1s) (p = 0.001). Operating time was shorter by 22% in the guided technique (3.2±1.2 min vs. 4.1±2.1 min p = 0.018).

In an experimental setting, the newly developed guided freehand technique has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method enhances established clinical workflows and does not require cost intensive add-on devices or extensive training.

A newly developed simple navigated technique has proven to markedly reduce radiation exposure and time for distal locking of intramedullary nails.

Many orthopedic departments provide their patients with implant-specific identification cards. These cards should assist patients in various security checks and while undergoing revision surgery, especially if performed far from the primary hospital. This retrospective study was performed to evaluate patients’ use of these cards.

In our department, each arthroplasty patient receives an implant-specific identification card. A phone survey was conducted among two groups of consecutive patients who underwent a lower limb arthroplasty – first group consisted of 108 patients operated a year earlier and second – 120 patients operated 3 years earlier. In the first group, 97 patients (90%) replied and in the second group – 83 patients (69%). The patients were asked the following: whether they received the card, where they keep it, what do they know about its purposes, and have they used the card for security or medical reasons.

17 patients (18%) in one-year group and 18 patients (22%) in three-years group didn’t remember the card. The rest of the patients knew the location of the card, but most of them (80% in one-year group and 72%in three-years group) knew only about the security usage of the card and not about the medical one. Many patients complained that they were not given adequate explanations about the card.

Implant-specific identification cards have significant value for arthroplasty patients. However, patients use them mostly for security checks. The medical usage of this card should be explained when they receive it, so the patients can assist their surgeons while performing a revision surgery.

Introduction: The postoperative rehabilitation after a primary knee arthroplasty may be infiuenced by a variety of factors. Nevertheless, only a few studies evaluated the effect of various factors on patients’ short-term outcome. This prospective study was conducted to evaluate the effect of different factors on patients’ function six weeks after the surgery.

Patients and methods. We prospectively recruited 107 patients with osteoarthritis who underwent an uncomplicated total knee arthroplasty, using the same prosthesis and operative technique. Following variables were collected before and after the surgery: age, BMI, visual analogue pain score at rest and during activity, preoperative range of knee motion, involvement of other joints, comorbidities (Katz index), self assessed health status, admission and discharge hemoglobin levels, amount of blood transfusions and intensity of postoperative physiotherapy.

In order to quantify patients’ level of functioning, we used a timed up and go test (TUG) and the Oxford knee score that were collected before and after the surgery. To eliminate the infiuence of postoperative weakness on rehabilitation, hand grip measurements were performed as well. A multivariate regression analysis was performed to examine the infiuence of different peri-operative variables on the outcome measures. Adjusted R2 was measured to estimate the explanatory power of infiuence of these variables.

Results: There was no significant difference between preoperative and postoperative hand grip force measurements, indicating that the general strength of the patients did not deteriorate. A postoperative TUG was worse with higher preoperative TUG and higher rest pain score (adjusted R2=0.53). The amount of improvement in TUG was better only with lower rest pain score (adjusted R2=0.06). A postoperative Oxford hip score was better only with lower rest pain score (adjusted R2=0.30). The amount of improvement in the Oxford score was not infiuenced by any of the variables (adjusted R2=0.01). Only significant infiuences (p< 0.05) are mentioned.

Discussion: Most of preoperative and postoperative measured variables, including age, BMI, comorbidities, hemoglobin concentration and amount of physiotherapy had no significant effect on patient’s functional status after uncomplicated knee arthroplasty. Only the pain at rest had infiuence on the functional result. These results suggest that patient personality has a most significant effect on knee arthroplasty results, either through pain perception or otherwise.

Introduction: Distal radius fracture in postmenopausal women is often the first clinical symptom of osteoporosis. Both patients and family physicians are generally unaware of this. It is estimated that only 15–25% of postmenopausal women with a distal radius fracture are further referred to perform a bone density examination. The purpose of the current study was to examine whether a simple intervention by the hospital staff would increase the percentage of patients that undergo diagnostic workup after suffering a fracture in the distal radius.

Patients and Methods: This prospective study included 99 women aged 48–70 seen in the emergency room for a distal radius fracture. All patients were contacted 6–8 weeks after the ER visit and asked as to whether they had received an explanation from the hospital or from the family physician about the significance of the fracture for osteoporosis, and whether they had been referred to a bone density examination. 49 patients served as a control group. The intervention group (50 patients) were then given a detailed explanation regarding the implications of the fracture for osteoporosis, and in addition, received a letter with an explanatory leaflet and an appeal to the family physician with recommendations and an article on osteoporosis.

An additional telephone survey was conducted 6–8 weeks after the first conversation to assess the influence of the intervention.

Results: 15 patients in the intervention group and 14 patients in the control group were lost to follow up or were already treated for osteoporosis before the fracture. At the second phone call 24 patients (72.7%) from the intervention group had contacted their family physician after the intervention, compared to 8 patients (22.9%) in the control group (p=0.0003). 14 patients (42.4%) from this group underwent a bone density examination, compared to 5 patients (14.3%) in the control group (p=0.0003).

Conclusion: It is of great importance that patients understand the connection between the current problem for which they are receiving treatment in the emergency setting and the possibility that there is an underlying cause. In addition the connection between the hospital and the community is very important in increasing the number of patients diagnosed and treated.

Introduction: In 2003 the Ministry of Health in Israel added hip fractures to the DRG listing. The rational behind this move was aiming at the shortening of hip fractures waiting time to surgery and shortening of hospitalization period. Some hospitals in Israel have assigned an additional OR shift for this purpose. Hip fracture patients consist of two main sub-groups: patients who undergo hemi-arthroplasty (HA Group) and those who undergo internal fracture fixation (IFF Group). The new policy determines that DRG of internal fixation patients ends at the fifth day of their initial hospitalization after surgery. The aim of this study was to evaluate the practical effect of this policy on hip fracture management.

Patients and Methods: We retrospectively compared two major groups of patients (total 808) with hip fractures: the first group of patients was treated in 2001 (377 patients) (before the new policy came into effect) and the second in 2005 (431 patients). Each of these groups included the HA group and the IFF group. In each of the groups we compared the time to surgery, length of hospitalization, mortality rates after six months and the diurnal distribution of the operations.

Results: The length of hospitalization in 2005 was found to be shorter in the IFF group by 2.82 days (2001 – mean stay of 12.52, 2005 - 9.7 days) as opposed to the HA group where hospitalization was shorter in 2005 by a mean of only 0.42 day. Mortality rates at six months following surgery, when comparing the two major groups, were 11.3% in 2001 and 7.9% in 2005. 90% of the operations in 2005 were performed between 15:00–19:30 compared to 2001 when 90% of surgeries were evenly distributed between 15:00 and 24:00. We did not find statistically significant differences between the groups in relation to the time to surgery before and after the new policy. There was a trend towards a longer waiting time to surgery in the HA group in 2001 as well as in 2005.

Discussion: The presence of a dedicated shift, according to the new policy, made more room available for other emergency list surgeries. Hospitalization stay became shorter due to the fact that the insurer is committed to discharge patients from the IFF group after 4 days of hospitalization and to finance each additional day. In spite of the fact that waiting time to surgery was not shortened following the new policy, the majority of surgeries were performed during the afternoon sessions. It should be noted that in 2001 waiting time to surgery was already very short. Mortality data are interesting and necessitate further investigation.

Purpose: Fracture reduction (FR) during intra-medullary nailing of long bone fractures requires an extensive use of fluoroscopic radiation. Fluoroscopy based navigation system using custom FR software is introduced of which the main advantage is its ability to track simultaneously the two fracture segments during fracture reduction. The aim of this study was to test the feasibility of this system.

Methods: 26 Patients 17 males and 7 females suffering from 10 tibial shaft and 14 femoral shaft fracture were operated using the FR software. Two trackers were attached to each of the main fracture segments. Image registration was done by acquiring fluoroscopic images including the fracture site and the two metaphysial areas of the long bone on both perpendicular planes. The system uses two cylinder models representing the fracture segments, each defined between two points chosen by the surgeon on the acquired images, these are tracked by the system. Fracture reduction was qualitatively evaluated as well as other features of the system. Overall radiation was registered.

Results: A small number (< 10) of flouroscopic images was acquired; this decreased as we gained more experience. FR software was helpful in all the cases and accomplished good and quick reduction; it reduced the need for added radiation to 2–4 verification images.

The system was utilized as well in all cases for choosing the nail point of entry, in 7 (25%) for blocking screws planning and in 4 (16%) for nail locking successfully.

Conclusion: The FR software enabled and improved significantly the performance of this surgical task with a dramatic decrease in radiation and FR time. The software still lacks the fine tuning needed for best performance.

Introduction: Reversed oblique subtrochanteric fractures are unstable and pose a surgical challenge. Fixation with Dynamic Hip Screw is prone to collapse with medial displacement and high rate of non or mal union. The use of Proximal Femoral Nails may result in non anatomical reduction which delays union and impedes rehabilitation. PCCP is a percutaneous plate originally designed for fixation of intertrochanteric fractures. However, the plate supports the greater trochanter and can prevent collapse of subtrochanteric fractures and rigidly secure the femoral neck. This study summarized our experience in fixating reversed oblique subtrochanteric fracture with the PCCP technique.

Patients and Methods: Between January 2005 and March 2006 26 patients who sustained reversed oblique subtrochanteric fractures (AO-31A3) were consecutively treated with PCCP. Two patients died and were excluded from this study. Patients’ age ranged between 58 and 93 (average 86, median 80). Follow-up was between 6 to 20 months (average 12). All patients were operated on a standard fracture table with the use of posterior reduction device. An attempt to reduce the fracture was done in each case prior to the surgical incision. In the majority of cases the shaft was displaced medially to the greater trochanter. The PCCP plate was introduced percutaneously and the medially displaced shaft was pulled to the plate using the reduction clamp. The rest of the procedure was done according to the regular technique of the PCCP. All patients were instructed to refrain from weight bearing for six weeks after the surgery and then resume full weigh bearing. Follow-up was in the out patient clinic 6 weeks, 3 months and one year after the surgery.

Results: Time of surgery varied between 35 to 75 minutes. There were no patients who were planned to undergo this procedure and were diverted to a different modality of fixation. All the procedures were done percutaneously. Anatomic or near anatomic reduction was achieved in all cases. All patients resumed full weigh bearing six weeks after the surgery. All but one fracture united. The patient whose fracture did not unite was blind and fell a few times during rehabilitation and eventually suffered from pull-out of the plate from the femur with breakage of the shaft screws. She underwent revision surgery with bone graft and the fracture united. Follow-up radiograms showed that the reduction was maintained in all but three patients. Medial displacement of 8–15 mm occurred in 3 patients. There were no infections.

Conclusions: While there is an ongoing debate among “nailers” vs. “platers” for the fixation of femoral neck fractures, PCCP combines the theoretical advantages of both percutaneous technique and absolute stability. In this study this biological system was found to be a reliable solution for the challenging fixation of reversed oblique (AO-31A3) subtrochanteric fractures, with high union rate, fast recovery and low complication rate.

Purpose: The purpose of this study was to assess the safety and efficacy of computed tomography (CT) guided percutaneous radiofrequency (RF) ablation of osteoid osteoma by using the water-cooled probe.

Patients & Methods: During the period from July 2002 to February 2006, fifty-one patients with osteoid osteomas localized in femur (30), tibia (9), calcaneus (2), talus (2), metatarsus (2), humerus (1), sacrum (1), scapula (1), olecranon (1), patella (1) and thoracic vertebra (1) were treated with CT-guided RF ablation using the Cooltip™ Tyco Healthcare probe. Mean age was 20 (range, 3.5 to 57) and male to female ratio was 35/16. Mean follow-up period was reported 22 months (range, 8 to 50 months). The procedures were carried out under general anesthesia and the patients were discharged from the hospital within 24 hours.

Results: Technically, all the procedures were performed successfully. Pain disappeared postoperatively in all the patients within 2–3 days and no patients needed analgesic treatment after a week. All patients were allowed fully weight bear and function without limitation after the procedure. Recurrence of the pain was observed in one patient who was treated successfully with a second ablation. Our primary and secondary clinical success rates were 98% and 100% respectively. In one case, wound infection was observed after the procedure as the only post-operative complication in our series.

Conclusion: CT-guided percutaneous RF ablation of osteoid osteomas using the water-cooled probe is a safe, effective and minimally invasive procedure with high success rate and lack of relapses.

Osteoporosis is a very common disease in the elderly, generally undertreated. Hip fracture is often the first clinical painful symptom of osteoporosis. It would seem that hip fracture should be a good opportunity to convince the patient of the importance of osteoporosis treatment. We conducted this study to check whether a simple intervention improved the compliance of osteoporosis treatment.

100 consecutive elderly patients with osteoporotic hip fracture received, during postoperative hospital stay, a 5–10 minutes long explanation about osteoporosis, its sequelae, treatment options and their effectiveness in further fracture prevention. Patients received an explanatory brochure and a letter to family physician that included a recent article on fracture rate reduction with osteoporosis treatment. Compliance was examined by telephone survey 3 and 6 months postoperatively.

100 consecutive patients with similar demographic characteristics who were treated for hip fracture prior to intervention served as a historical control. All patients received a recommendation for osteoporosis treatment in the discharge letter.

At follow up, 40% of patients in the study group were receiving biphosphonates, as opposed to 20% in the control group (p< 0.01). 77% of control patients received no treatment for osteoporosis compared to 37% of patients after intervention (p< 0.01).

Giving the patient a short explanation about osteoporosis combined with a letter to family physician, resulted in a significant improvement in their compliance The orthopaedic surgeon, who treats the patient at the first painful symptom of osteoporosis, has an excellent opportunity to improve patient’s understanding of the disease and her or his compliance to treatment.

Introduction: Currently patients who had undergone lower limb arthroplasty are discharged a few days after surgery, at which stage they still need anticoagulation treatment. The transition from hospital to the community is a sensitive period and is susceptible to mistakes and misunderstandings. Patients may underestimate the importance of the continuing treatment and their inconvenience to self-administrate subcutaneous treatment might decrease their compliance. The purpose of this prospective cohort study was to investigate the continuity of the treatment with subcutaneous low molecular weight heparin at the transition period from the hospital to the community.

Materials and Methods: 209 consecutive consenting patients who had undergone lower limb arthroplasty were recruited. Ten were excluded from the study since they were subscribed oral anticoagulation; 4 patients developed pulmonary embolism and were not included, and 8 patients were lost to follow up. 187 patients were followed weekly by phone and were asked about their adherence to the daily treatment, about clinical signs suggesting a thromboembolic event and whether they sought medical assistance. Three months later there was another clinical follow up.

Results: Of the 187 patients, 174 (93%; 95% CI 88.9% < p < 96.4%) were compliant. The percentage of doctor visits by TKR patients was statistically significantly higher, (p=0.007) than by THR patients. There was no significant difference in the compliance of patients who live with their families and patients who live alone. Patients with 0–6 years of education tend to search medical advice statistically significantly more (p=0.004) than patients with more than 7 years of education.

Discussion: The rate of compliance to anticoagulation treatment with subcutaneous low molecular weight heparin was encouraging. It demonstrates that the patients understand the necessity and importance of the treatment.

Introduction: The common belief is that navigation-assisted TKR improves the surgical accuracy and reduces outliers, albeit increasing the operating time. We conducted a detailed study of the published studies with four main criteria:

Reduction of outliers in the placement of implants.

Methods: We performed a computerized search of the PubMed repository and a manual search of the proceedings of the International Society for Computer Assisted Orthopaedic Surgery (CAOS, 2001–05) to include all studies that presented clinical data of the results of this procedure. A total of 139 clinical studies were found, a total of 7,158 patients who underwent navigation-assisted TKR.

Results: Of the 139 studies, 39 studies presented data showing a reduction of outliers of the post-operative mechanical axis in the 180±3° range. 2,130 out of 2,401 (89%) patients operated with navigation were within this range. 27 out of the 39 studies compared the postoperative alignment of the navigated technique to that of the non-navigated technique. In the non-navigated technique, only 1,325 out of 1,880 (71%) patients were in that range, close to the published 74–75% for conventional TKR studies.

Regarding the operating time with navigation, 32 studies report an average increase of 21 min. (range 6– 48 min.), or about 20% than conventional TKR.

One of the perceived benefits of using extramedullary jigs in navigation-assisted TKR is thought to be reduction of blood loss. However, of the 15 studies that address this issue, 10 (67%) found no significant difference compared to the conventional technique. Regarding post-operative functional and/or pain scoring, 12 (80%) out of 15 studies found no statistically significant differences between navigated and non-navigated techniques.

Conclusions: The published clinical data so far shows that navigated-assisted TKR provides good alignment of the implants and a reduction of outliers from one in four to at most one in ten at the expense of 15–20 min. (about 20%) increase in operating time. No significant advantage was found for blood loss or functional/pain scoring. From a public health viewpoint, the increased cost of the navigated procedure may very well be compensated by the reduction of future revisions.

Introduction: Cigarette smoking is associated with musculoskeletal degenerative disorders and increased risk of fracture delayed- and non-union. A lower-than-average concentration of mesenchymal stem cells may be the reason for the reduced regenerative potential. The aim of this study was to compare the concentration of bone marrow MSC of smokers and non-smokers.

Methods: As part of a larger IRB approved clinical trial, 20ml bone marrow samples were processed and MSC were isolated. FACS analysis was used both to assess the purity of the separation process and to evaluate the number of MSC recovered from each sample. Differences in continuous outcomes between smoking and non-smoking groups were assessed by two tailed t test and difference between categorical outcomes was measured by chi square test.

Results: Twenty six subjects participated in the study. Thirteen were smokers and thirteen were non-smokers. Groups were not significantly different with regard to age and gender. The average concentration of MSC was 352.04x10³/ml for non smokers and 131.23x10³/ml for smokers (SD’s were 245.72 x10³/ml and 161.54 x10³/ ml respectively. The difference between the smokers and nonsmokers was significant (t=3.2 p=0.004).

Discussion: The present study indicates that cigarette smokers have lower-than-average concentration of MSC in their bone marrow. Since MSC are a key element in every regenerative process of the musculoskeletal system, our findings may contribute to understanding and prevention of delayed and non-union. Further investigation is undertaken to address the issue of bone marrow recovery after smoking cessation.

Background: The purpose of this study was to analyze the applicability and advantages of the intraoperative use of a mobile isocentric C-arm with 3-dimensional imaging (SIREMOBIL ISO-C-3D) in fixation of intraarticular fractures.

Methods: Intraoperative CT-quality visualization was performed on a series of 72 closed-intraarticular fractures in 70 patients following fixation. Fracture distribution was; calcaneus (25), tibial plateau (17), tibial plafond (12), acetabulum (11), distal radius (3), ankle (3), femoral head (l). The mean patient age was 41. Intraoperative revision was performed based on the additional information Iso-C-3D provided beyond routine fluoroscopy used for fracture reduction and fixation. The primary outcome measure was revision rate after final Iso-C-3D data acquisition and prior to wound closure. Secondary objectives were to measure the additional time required for Iso-C-3D use and to determine the rate of further re-do surgeries.

Results: Eight out of 70 (11%) fracture fixations were judged by the surgeon to require intraoperative revision following Iso-C-3D imaging. In 7 cases this was due to hardware misplacement and in 1 this was for intraarticular loose fragment. Prior to leaving the operating room, the surgeon was satisfied with fracture alignment in all the procedures. The mean additional operative time using Iso-C-3D was 7.5 minutes. No patient required re-do surgery.

Conclusion: Intraoperative 3-dimensional visualization of intraarticular fractures enables the surgeon to identify inadvertent malreductions or implant malpositions which may be overlooked by routine C-arm fluoroscopy and hence eliminates the need for re-do procedures. Iso- C-3D adds little operative time and may preclude the need for preoperative and postoperative CT-scans in selected cases.

Limited access surgery is thought to reduce post-operative morbidity and provide faster recovery of function. The percutaneous compression plate (PCCP) is a recently introduced device for the fixation of intertrochanteric fractures with minimal exposure. It has several potential mechanical advantages over the conventional compression hip screw (CHS). Our aim in this prospective, randomised, controlled study was to compare the outcome of patients operated on using these two devices.

We randomised 104 patients with intertrochanteric fractures (AO/OTA 31.A1–A2) to surgical treatment with either the PCCP or CHS and followed them for one year postoperatively.

The mean operating blood loss was 161.0 ml (8 to 450) in the PCCP group and 374.0 ml (11 to 980) in the CHS group (Student’s t-test, p < 0.0001). The pain score and ability to bear weight were significantly better in the PCCP group at six weeks post-operatively. Analysis of the radiographs in a proportion of the patients revealed a reduced amount of medial displacement in the PCCP group (two patients, 4%) compared with the CHS group (10 patients, 18.9%); Fisher’s exact test, p < 0.02.

The PCCP device was associated with reduced intra-operative blood loss, less postoperative pain and a reduced incidence of collapse of the fracture.

Introduction: Cell-based strategies for regeneration and reconstitution of musculoskeletal tissues are gaining interest. The difficulty in obtaining the required amount of mesenchymal stem cells (MSC) stems from their scarcity and the time needed to grow them in culture. We developed a rapid and efficient method to isolate MSC from bone marrow aspirate based on their surface markers, as a platform for future cell based therapy.

Methods: Bone marrow was aspirated from the iliac crest of fifteen adult subjects undergoing surgeries involving this bone. 15 ml samples were obtained, fractionated for mononuclear cells and then subjected to immunomagnetic isolation using microbeads of directly conjugated mouse anti–human CD105 antibodies. Recovered cell fraction was analyzed for phenotype and functional parameters.

Results: The samples yielded an average of 14.6±2.5x10⁶ mononuclear cells per ml. Of these, fraction of CD105 positive cells consisted of 2.3±0.45%, which accounts for 0.25±0.06x10⁶ cells per ml. Post isolation analysis shows that 79±3.2% were positively stained for CD105 and 36±5.8% stained positive for CD45. These cells generated 6.3±1.4 Colony Forming Units (CFU) per 10⁵ cells. MSC concentration is higher in males and lower in smokers. Processing time is approximately 3 hours.

Discussion and Conclusion: Regeneration of mesenchymal tissues using progenitor cells with appropriate matrix and signals was shown feasible, however large numbers of these rare cells are needed. An effective and safe method for purification of autologous MSC enables us to avoid the risks and the time span associated with culture expansion. We conclude that this method is both effective and rapid.

Introduction: Fluoroscopy-based navigation systems enables surgeons to place implants with a simultaneous multi-planar monitoring. Percutaneous fixation of femoral neck fractures is an example of the growing usage of these systems in orthopedic trauma surgery. Growing evidence suggests that the accuracy of screw placement might affect the fracture outcome.

Methods: Between 2/2001 and 8/2005, 80 patients underwent internal fixation of femoral neck fractures using computerized navigation system. Three cannulated screws were implanted in an inverted triangle formation. The average patient’s age was 62±20 years (range 11–88), and 12 patients were under the age of 40 years. 53 patients were female, 27 male. 68 patients sustained the fracture due to a simple fall, 4 fell from high ground, 3-bicycle injuries, 2 due to motor vehicle accidents, and 3 patients suffered from insufficiency fractures with no trauma. The data includes results for both undisplaced fractures and fully displaced fractures which underwent closed reduction.

Results: The average length of hospital stay was 6.3±4 days (range 1–19). The average operating room time was 82±22 minutes (range 30–135), this including the preparation of the patient and instrumentation. Complications included one case of infection which necessitated long term antibiotic treatment, four patients requiring hip arthroplasty due to avascular necrosis of the femoral head, and one patient who underwent hip arthroplasty due to osteoarthritis. The total failure rate is 6%.

Conclusions: Computerized navigation for the internal fixation of subcapital femoral neck fractures allows improved screw positioning, which may reduce fracture complications, and provides reduced radiation to both the surgeon and the patient.

Introduction: Spinal fusion has become a popular surgical technique. Problems of fusion failure or pseudo-arthrosis as well as bone graft donor site complications are common. Ex vivo gene therapy using mesenchymal stem cells (MSCs) and bone morphogenetic protein (BMP) genes can provide a local supply of precursor cells and a supra-physiological dose of osteoinductive molecules that may promote bone formation and lead to spinal fusion.

Methods: Thirty 6–7 weeks old C3H/HeN immune-competent female mice received an injection of 2x10⁶ genetically engineered MSCs to the para-vertebral muscle of the lumbar spine (L2-L6) under manual palpation. Ten animals served as negative control group and 20 animals constituted the experimental group.

Bone formation in the para spinal region of the injected animals was evaluated by histology staining. Quantitative analysis of the fusion mass was monitored by micro computerized tomography (μCT).

Results: At 1, 2, 4 and 8 weeks post injection. Bone formation was extensive, as soon as the 1^st week post injection, in the area adjacent to and adhering to the posterior elements of the spine in all the study animals. None of the control animals, in which hBMP-2 was inhibited, showed any new bone formation.

Discussion: Exogenously regulated expression of the hBMP-2 enabled us to regulate bone formation in vivo, using genetically engineered MSC system. The effect of hBMP-2 in inducing bone formation was monitored in real time, non-invasive and quantitative system that enabled us to better understand the biological process during bone regeneration and repair. Our data demonstrate a regulated and monitored system for inducing bone for spinal fusion. We conclude that controlled gene therapy for spinal fusion can be achieved using Tet-regulated hBMP-2 gene and MCSs.

Introduction: To enable navigated-assisted orthopedic surgery, a reference frame must be rigidly fixed to a stable bony structure. This may create technical obstacles and wound complications. Instead, we propose to attach the reference frame to the fracture table.

Methods: The study population consisted of 10 patients who underwent fixation of subcapital femoral neck fracture with three cannulated screws, using fluoroscopy-based navigation. Step 1 – the patient was positioned on a fracture table and the reference frame was attached to the iliac crest. Three guide wires were inserted under fluoroscopy-based navigation. 2 – New fluoroscopic images were acquired. 3 – Navigated drill guide placed over each guide wire to record final navigated drill guide position – these images include actual guide wire positions and the trajectories of the navigated drill guide. Navigation accuracy was validated, measuring translational and angular deviations of the virtual trajectory from the implant on the same fluoroscopic image in anteroposterior and lateral views. 4 – The reference frame was removed from the iliac crest and attached to the fracture table. Step 3 was then repeated.

Results: The translational deviation of the virtual trajectory from the inserted guide wire when the reference frame was attached to the iliac crest was not statistically significant from the deviation when it was attached to the fracture table. Angular differences were also not statistically significant.

Conclusions: In our experience, attaching the reference frame to the fracture table instead of to the iliac crest allows for similar accuracy of the navigation process with the possible benefit of reducing patient morbidity.

Introduction Musculoskeletal injuries, especially fractures, cause reduced limb mobilization. The diminished limb activity promotes muscular atrophy, leading to a slower return to function. Attempts to prevent this atrophy using electrical stimulation have been described after knee reconstruction.

The Myospare percutaneous electrical stimulator has been developed to prevent immobilization related atrophy. We undertook this pilot study to assess feasibility, safety, and efficacy of applying electrical stimulation under a cast after ankle fractures.

Patients and Methods Between May and December 2004, patients who sustained closed ankle fractures requiring surgery, were recruited to participate in this study. 24 patients took part in the study, sixteen male and eight female. Age range was 18 to 62 years (average 40). All patients underwent open reduction and internal fixation using standard AO technique. A short walking cast was applied after surgery. Patients were randomized into a treatment and a control group. The experimental device was applied in the treatment group for 6 weeks. Patients were examined at 2, 6 and 12 weeks.

Evaluation included measurement of calf and ankle circumference, dorsiflexion and plantiflexion, and calculation of the ratio between the injured and uninjured side. At each visit pain intensity was assessed using a visual analog score, and patients filled out a function assessment questionnaire. Analysis was performed using chi square, t-test and repeated measures analysis.

Results All patients tolerated the stimulator well. No adverse effects were encountered. There is a trend toward improvement in calf diameter, dorsiflexion and plantarflexion. However, with the small number of patients in this study, no significant difference was apparent. Functional recovery and VAS scores were borderline higher in the treatment group at 12 weeks (p=0.043 and p=.049) when compared to baseline.

Discussion The use of the Myospare device under a cast in patients after surgical fixation of ankle fractures has been demonstrated as feasible and safe. In this pilot study a trend toward enhanced recovery was apparent in the treatment group.

Background: The purpose of this study is to evaluate the applicability and advantages of the intraoperative use of a mobile isocentric C-arm with 3-dimensional imaging (SIREMOBIL ISO-C-3D) in trauma surgery.

Patients & Methods: Between November, 2004 and September, 2005, the ISO-C-3D was used at our institution for intraoperative CT-quality visualization of 33 trauma cases with the fractures of calcaneus (13), tibial plateau (7), tibial plafond (6), acetabulum (4), distal radius (2) and talus (1). The mean patient age was 42 and male to female ratio 25 to 8. In 30 cases ISO-C-3D was used during the surgery after the reduction and fixation of the fracture to assess the accuracy of reduction and implant position prior to wound closure and in 3 cases the device was used before starting the operation to obtain real-time CT images which were transferred to a navigation system to perform computer navigated procedures.

Results: This novel technique was highly beneficial from 4 aspects; intraoperative diagnosis, proper reduction, correct implant placement and feasibility in combining the CT images to computer navigation. In 40% of the cases (13/33) who had no regular CT scan before the surgery, intraoperative three dimensional imaging with ISO-C-3D has been a superior modality in diagnosis. In one case the reduction and implant position was corrected during the surgery after the ISO-C-3D scan. In all the procedures with ISO-C-3D navigation, satisfactory reconstruction of the articular surfaces with precise fixation was achieved.

Conclusion: Intraoperative 3-dimensional visualization with ISO-C-3D provides useful information in trauma surgery which enables the surgeon to re-evaluate the injury diagnostically and to judge the reduction and implant position before wound closure. Combining the ISO-C-3D images with computer navigation makes the reduction and implant placement highly accurate.

Introduction: Several factors render plain X-ray radiographs of the hip unsuitable for bone mineral density measurements, mainly variability in X-ray exposure levels and soft tissue surrounding the bone. We present modification of proximal femur digital radiographs to compensate for these interfering factors.

Methods: The study population consisted of 99 women, in three groups: 1 – elderly, sustaining a fracture of the neck of the femur. 2 – elderly, without a fracture. 3 – young. Each patient’s hip was radiographed with a brass step-wedge for standard reference. Dual-Energy X-ray Absorptiometry (DEXA) of the same hip was performed. On each radiograph, Regions Of Interest (ROIs) of the proximal femur were determined in concordance with ROI of the DEXA, together with three soft tissue regions surrounding the bone. Mean gray level was measured for each ROI.

Results: The difference in gray level of the ROI within the proximal femur was not statistically significant between the groups. Correction of bone gray level to exposure level by dividing the gray level of the ROI to that of the step wedge, resulted in statistically significant difference between group 1 and either group 2 or group 3. Similar results were obtained by correction of bone gray level to soft tissue gray level. Using this method, multiple R² of 0.62 was found predicting the DEXA value from the gray level of each ROI.

Conclusions: After correction to the exposure level and to the soft tissue surrounding the bone, a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur. These preliminary results warrant further research aimed at exploring the potential value of this fast, accessible and relatively inexpensive technique to diagnose osteoporosis and the prediction of future fractures.

Introduction: Non union of the humerus in the ostoeportic bone is a great challenge for the orthopedic surgeon. The non weight bearing nature of this bone together with extreme osteoporosis seen in the elderly had rendered a high degree of failure in different modes of internal fixation of established humeral non union. Tantalum is a trabecullar metal with biomechanical properties similar to bone with a high modulus of elasticity and low rigidity. It is proved both in vitro and in vivo to induce excellent bone and vascular in growth and have been used successfully treating other application in orthopedics. We have introduced the tantalum rod for the treatment of humeral non union in the elderly.

Patients and Methods: Six patients with humeral non-union were selected for tantalum rod implantations. All were above 60 years old. All patients had established non and 4 had failures after previous osteosynthesis. The surgical technique was exploration of the fracture site via a posterior or an anterolateral approach, debridement of the fracture site and intramedullary insertion of a 100 mm x 10 mm tantalum rod. No bone grafting was used. Ancillary fixation included a 4.5 broad DCP plate with screws drilled into both bone and rod or screws alone drilled into the bone and tantalum construct. Follow up period was up to one year.

Results: All fractures united clinically and radiographicaly up to 3 months. All patients achieved satisfactory shoulder and elbow range of motion and regained functional activity. No infection or foreign body reaction was noted.

Conclusion: Intramedullary tantalum rodding is a viable treatment option for the cases in both primary and secondary non union of the humeral shaft in osteoporotic bone.

Introduction: The most widely accepted method for measuring bone mineral density (BMD) is Dual-energy X-ray Absorptionmetry (DXA). However, the need for relatively expensive equipment and trained personnel lower the accessibility of DXA as a routine screening tool. Plain pelvic X-ray radiography is a simple and inexpensive examination. In principal, the gray level of the bone in the X-ray radiograph is related to BMD. However, several factors render plain X-ray radiographs of the hip unsuitable for BMD measurements, mainly the variability in X-ray exposure levels and the soft tissue surrounding the bone. In this study, we aimed to develop new modifications of plain X-ray radiography of the proximal femur.

Patients and methods: The study population consisted of 18 women with an average age of 77 years (range 57–96 years) who were hospitalized due to a low-energy fracture of the neck of the femur. Each patient’s contralateral hip was radiographed with an aluminium step-wedge positioned near the hip as a standard reference, using a computerized radiography system. A DXA examination of the same hip followed the plain radiograph. On each radiograph, regions of interest (ROI) were determined in concordance with the ROI of the DXA examination. The mean gray level was measured for each ROI. The neck-shaft angle and the femoral head diameter were also measured.

Results: Comparing the gray levels of the plain radiograph with the BMD levels obtained by the DXA revealed a coefficient ratio of R=0.499. Correction of the gray levels using the step wedge as a standard reference revealed a ratio of R=0.576. If further correction was made with measurement of the soft tissue gray levels, a ratio of R=0.708 was obtained. Using the anatomical measurements (neck-shaft angle and femoral head diameter), a ratio of R=0.948 was obtained.

Conclusion: This study shows that a plain digital radiograph of the pelvis can provide valuable information concerning the bone mineral content of the proximal femur, which is comparable to the results of the DXA examination. Ultimately, the research can lead to the development of a fast, available and relatively inexpensive technique to diagnose osteoporosis.

Introduction: Osteolysis is a significant problem associated with hip replacement. In the early stages of osteolysis, when the implant is still stable, formal revision is technically demanding and may result in signififant bone loss. A recently described technique for acetabular component revision addresses osteolysis, retaining the acetabular cup and cementing a new polyethylene liner.

Materials and Methods: Between January 2000 and December 2003, 29 liner cementation revisions in 27 patients were performed. The mean age was 61 years (range 37–77), the mean time elapsed after the original surgery was 6.7 years (3–14). 23 of the hips (79%) were ABG (Howmedica). Only 20 (69%) of the patients were clinically symptomatic. At surgery the polyethylene was removed and osteolytic cysts were debrided. Then, the metal acetabular component was tested for stability. Obviously, only stable metal implants were not revised. The cysts were filled with bone graft or bone substitute and a new polyethylene liner was cemented in with methylmetacrilate augmented gentamicin. The patients were evaluated by modified Harris Hip Score (HHS) and by SF-12 score. The mean follow up was 25 months (10–45).

Results: The average HHS was 86/4 and its pain component was 38.8. The average physical component of SF-12 was 45.9 (19.5–57.2) and the average metal component was 54.6 (29–66.9). The post-operative HHS and the SF-12 scores were high (good or excellent) in all patients reflecting good clinical outcome. In patients who were asymptomatic prior to surgery, both the HHS and the pain score were significantly higher compared to the symptomatic patients (p< 0.01). One patient with extensive bone loss needed revision surgery due to early postoperative fracture of the acetabulum, and another patient had recurrent dislocations that required revision.

Summary: We conclude that revision of the polyethylene liner and cementation of a new one is a safe and useful technique in patients with stable acetabular shell. This is especially true for asymptomatic patients with osteolysis.

Introduction: Necrotizing Fasciitis (NF) is a potentially lethal deep soft tissue infection. Correlation between prompt diagnosis and adequate surgical treatment and favorable outcome is well documented, however scarcity of specific cutaneous signs and the potential of evolution from otherwise simple infections may contribute to delay in diagnosis and treatment. Few clues may assist the physician to avoid overlooking this surgical emergency.

Patients and Methods: Sixty-eight patients were treated in our hospital for necrotizing fasciitis since 1990. In twenty-five of them the major involvement was peripheral, sparing the head, neck and torso. We reviewed these 25 cases for patterns of presentation and alarming signs for the first encountered physician, as well as for kinetics of treatment and outcome.

Results: Eight female and seventeen male patients aged 1–83 (average 53.6) years were treated. Only eight of them (32%) were free of comorbidities associated with reduced immunity. Majority of patients referred to the emergency department complaining of local pain/tenderness and erythema for few days accompanied by excruciating pain. Vital signs were often within normal limits, although leucocytosis on admission was common and gas was evident in the soft tissue by imaging. Surgical debridement was usually carried out on the day of diagnosis that was established immediately on admission in 10 cases (40%) but was delayed beyond 72 hours in seven patients (28%). CT scans showed severe edema and muscle liquefaction when taken. Thighs and gluteal region was the most common site of infection (56%) and cultures grew gram positive cocci (64%) and enteral flora (68%) in mono- and poly-microbial cultures. Only three cultures grew unaerobes, of which only one was clostridium. Accordingly, imaging studies showing gas in the soft tissue were uncommon. Eight patients (32%) have expired, and the average hospitalization period was over 38 days for the survivors.

Conclusions: NF is one of the surgical emergencies encountered by orthopedic surgeons. It is there, knocking at our door and will not go away… even a minor delay in diagnosis may be catastrophic to the patient, who often present with common signs and symptoms of mild to moderate skin infection. It should therefore be noted that pain inadequate for a minor infection was characteristic to most patients diagnosed with NF, and that CT findings may establish the diagnosis. Although considered pathognomonic, both crepitus and imaging finding of gas in the soft tissue are uncommon. Special attention to patients at risk and careful physical examination may lead to rapid diagnosis and treatment, and eventually lower the significant morbidity and mortality associated with this condition.

Introduction. Osteolysis is a periprosthetic bone loss associated with both cemented and noncemented arthroplasties. It is believed to be caused by cellular reaction to wear particles, especially from polyethylene, and is considered to be a major source of morbidity following total hip replacement. Roentgenographycally it appears as a diffuse cortical thinning or focal cystic lesion, but major bone loss may precede this finding. In advanced osteolysis, implant stability is impaired, and component revision is mandatory. Thus early detection of osteolysis is crucial to allow minor procedure of curettage and insert revision.

Three dimensional imaging tool for early detection and follow up of the osteolytic cysts is needed. The conventional CT incorporates streak artifacts around metallic implants that make the interpretation of the images extremely unreliable. We report our preliminary experience with new 16-slice CT techniques that improve the diagnosis of osteolysis.

Materials and methods. Twenty one patients with suspected osteolysis underwent CT examination of the involved region with a new 16-slice GE Lightspeed scanner. 16 patients had a hip arthroplasty and 5 patients a knee arthroplasty. Different slice thickness was examined. Standard, soft and boneplus filters were tested for the axial images and reconstructions. MPR with 0.625mm, 1.25 and 2.5mm slice thickness, 3D-MIP and VR reconstruction methods were performed for each patient and the best technique for minimizing streak artifacts and evaluation of periprosthetic bone was determined by two radiologists and an orthopedic surgeon.

Results. The axial images in various slice thickness showed massive streak artifacts but the thinner slices of 0.625mm showed better demonstration of fine bony details around the prosthesis. Standard filter was superior compared to the soft and boneplus filters for bony changes. MPR and MIP reconstructions reduced markedly the impact of the metal artifacts but MPR using 1.25mm slice thickness was superior to MIP for appreciation of the texture of the periprosthetic bone.

Conclusions. In our study, a proper technique of 16-slice computerized tomography allows early detection and follow up of osteolytic lesions, that may significantly help in the decision making process, and may enable avoiding major surgery.

Introduction: Numerous studies had been published concerning the classification, biomechanics and the management of penetrating extremity trauma involving long-bone fractures. Significant controversy exists in protocols of the management and outcomes of these serious injuries. Bullets and multiple shrapnel injuries due to terror attacks may differ in injury pattern and severity. The role of immediate internal fixation still remains questionable. During a period of four years 92 patients suffering from 103 long bone fracture due to penetrating gunshot and shrapnel injuries were treated in our level I trauma center. The aim of this retrospective study is to evaluate the outcome of these patients regarding our treatment protocol.

Patients and Methods: 92 patients suffering from 113 long bone fractures caused by firearms and shrapnel injuries were treated in a level I trauma centre between 1/2000 and 12/2003. There were 36 femoral fractures, 50 tibial fractures, 5 humeral fractures and 24 forearm fractures. 43% of the patients suffered from associated injuries. Fifty eight percent of the patients had an Injury severity score (ISS) of 9–14 and 21% had an ISS greater than 25. 30% of the patients suffered form an associated vascular injury and 32% from an associated nerve injury of the fractured extremity. 36% of patients had multiple fractures. Overall mortality rate was 4%.

Results: 77% of the fractures were fixated primarily and 23% were splinted or put in a cast. 3% of limbs were amputated. Out of the primary fixation group, 45% of the fractures were fixed with intramedullary nails, 44% with an external fixator and 11% with plates. 28% of the fractures required arterial repair, 18% required nerve repair and soft tissue coverage procedures were needed in 14% of the fractures.

The infection rate for the entire group was 12%. Non-union occurred in 8%. Secondary amputation rate was 4%

Discussion: The surge of violence in our region had produced penetrating long bone injuries with increased severity, often associated with polytrauma, differing from other published series. Our management of these serious injuries was aggressive with the increased use of primary intramedullary nailing and internal fixation with comparable results of other published series. We conclude that aggressive primary surgical approach using multidisciplinary teams can result in favourable results in these unique patients subset.

Introduction: Decreasing the length of the side plate of the dynamic hip screw (DHS) would theoretically allow a smaller surgical incision, a shorter surgical time, decreased operative blood loss and minimal periosteal stripping. A new design of a very short plate (VSP) dynamic hip screw based on two diagonal screws has been developed. The new design was compared with the four hole side plate regarding its mechanical properties and bio-mechanical outcomes.

Methods: Four pairs of fresh frozen cadaveric femora were extracted from male corpses aged 25–43 (mean 34.8), mechanical loading was applied to four pairs of cadaveric femora which were fixated using the new system on one side and the conventional design on the other. The decline during the periodical loading and the breakage load of the fixated bones were measured. In addition, mechanical performance and probability for failure was assessed by conducting a mathematical analysis using the finite element method.

Results: The average deflection under excessive cyclic loading was 33% higher in bones with the VSP-DHS device than those with regular DHS. The average load failure during the collapse loading test was 312 kg for the VSP-DHS compared to 416 kg for the regular device. The mathematical analysis performed indicated that the maximal stress in the VSP-DHS reached values 3–4 fold higher than in the regular DHS.

Conclusions: Bio-mechanical evaluation was performed both by mechanical testing and theoretically. Although the new design offers a minimally invasive approach to subtrochanteric femur fracture fixation, it was found to have insufficient biomechanical performance resulting in high probability for mechanical failure.

Introduction: Minimally invasive surgery (MIS) is associated with reduced postoperative morbidity and faster recovery of function. The PerCutaneous Compression Plate (PCCP) device was recently developed by Got-fried as a MIS technique for the fixation of osteoporotic hip fractures. PCCP provides rotational stability by means of two hip screws, and lateral cortical support by a proximal extension of the plate and by the relatively small diameter (9.3 mm) of the hip screws. The purpose of this prospective study is to compare the outcome of PCCP to the “gold standard” Compression Hip Screw (CHS) device.

Methods: 104 Patients with intertrochanteric fractures were randomized to be treated by PCCP (50 patients) or CHS (53 patients). One patient was switched from PCCP to CHS during surgery. Inclusion criteria were age above 60, close fracture reduction, no pathological fracture, and no surgical procedure in the same leg in the last year.

Results: The groups were comparable in patient age, gender, ASA, length of surgery and hospital stay. Operative blood loss was 177.8 ml in the PCCP group and 371.3 ml in the CHS group (p< 0.0001). At the 6^th week clinic visit, patients in the PCCP group were able to bear more weight on the injured leg than patients in the CHS group (p< 0.03). Mortality during the first year follow-up period was 10% in the PCCP group and 24.5% in the CHS group (p~0.05). Analysis of X-ray radiographs revealed collapse in 4% of the patients in PCCP group and 19% in CHS group (p< 0.01).

Conclusions: Our results suggest that PCCP provides some of the advantages of MIS: reduced blood loss, as well as improves the stability of fracture fixation, demonstrated by improved early weight bearing and less fracture collapse. We found a trend for decreased first year mortality rate.

Introduction: When subjected to strain or strain rates are higher than usual, the bone remodels to repair microdamage and to strengthen itself. During the initial resorption phase of remodeling, the bone is transitorily weakened and microdamage can accumulate leading to stress fracture.

Methods: To determine whether short –term suppression of bone turnover using bisphosphonates can prevent the initial loss of bone during the remodeling response to high bone strain and strain rates and potentially prevent stress fractures, we conducted a randomized, double blind, placebo-controlled trial of 324 new infantry recruits known to be at high risk for stress fracture. Recruits were given a loading dose of 30 mg of residronate or placebo daily for 10 doses during the first two weeks of basic training and then a once a week maintenance dose for following 12 weeks. Recruits were monitored by biweekly orthopedic examinations during 15 weeks of basic training for stress fractures. Bone scans for suspected tibial and femoral stress fractures and radiographs for suspected metatarsal stress fractures were used to verify stress fracture occurrence.

Results: By the intension to treat analysis and per protocol analysis, there was no statistically significant difference in the tibial, femoral, metatarsal, or total stress fracture incidence between the treatment group and the placebo.

Discussion: We conclude that prophylactic treatment with residronate in a training population at high risk for stress fracture using a maintenance dosage for the treatment of osteoporosis does not lower stress fracture risk.

With obesity on the rise in Israel, most of the medical staff will probably encounter the unique challenges that result from the pathophysiological changes in this population. Morbid obesity is a chronic disease manifesting itself in a steady and slow-progressive increase in body weight. Currently, BMI is considered the best score for morbid obesity definition and it is calculated by dividing the body weight (kgs) in body surface area (m2). The score for morbid obesity is above 40 kg/m2 and has many systemic implications such as hypertension, diabetes, cardiovascular changes, especially it effects the musculoskeletal system. Complex multiple trauma in morbid obesity patients present a challenge throughout all stages of treatment: assessment of injury, preliminary care, and definitive surgical approach.

In the last two years five morbid obese patients (all weighted more than 150 kgs) sustained various degrees of high-energy multiple-trauma and were operated on in our institution. The patient presented with the following injuries:

Femoral fracture.

The preoperative, operative and post-operative care presented special curative dilemma and pitfalls which required modifications in regular treatment modalities such as improvisation in special equipment and surgical techniques. The operating tables had to be changed so they could sustain the increased patient’s weight and allow, in the same time, modified percutaneous surgical approaches to overcome the anatomical problems. In all patients we were able to achieve the main goal of trauma treatment, i.e. stable fixation of fractures and mobilization.

The experience we have gained in managing and overcoming these obstacles may serve as a basis for devising guidelines for the comprehensive treatment of these patients.

Introduction: Fluoroscopy is routinely used for real-time intra-operative localization of patient anatomy and surgical instrument positioning. Using this radiographic information the orthopedic surgeon inserts different implants into bone. Despite its utility, however, fluoroscopy does have disadvantages. The most notable is potential occupational radiation exposure. Conventional fluoroscopy usually provides only one plane at a time, whereas at least two planes are needed for optimal placement of an implant. By combining a standard C-arm fluoroscopy with computer aided surgical technology, radiation exposure can be eliminated and four different planes can be visualized simultaneously. This study presents data of preliminary clinical experience using this new technology.

Material and methods: The Stealth Station Treatment Guidance Platform System by Medtronic was used. The calibration target was attached to a C-arm fluoroscope. The static reference arc which was attached to the patient and various surgical tools. All with affixed light emitting diodes (LEDs) which were seen by the Infra Red camera. After a short registration process in which the relevant anatomy images were acquired, the C-arm was withdrawn and the entry point to the operated anatomy was determined using the navigation capabilities of the system.

During a period of six months, 31 patients underwent different surgical procedures in which a guided wire was used for: percutaneous fixation of unstable pelvis and hip fractures (13 patients), inserting and locking of an intrameduallry nail (12 patients), inserting pedicular screws (2 patients), or removing foreign-bodies or internal fixations (4 patients). In all cases the placement of the hardware was approved by conventional fluoroscopy as well.

Results: Excellent correlation between the virtual fluoroscopic imaging and live fluoroscopy was observed, thus the placement of the wire in all cases was satisfactory and there was no need to change the position of the wire following the live fluoroscopic confirmation. The number of fluoroscopic buttoning was smaller than the average number in similar surgery using conventional fluoroscopy.

Discussion: According to our preliminary clinical experience it seems that virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. Our impression is that its saves fluoroscopic radiation exposure and improves exactness of the procedure. However, since currently only one reference arc can be detected at a time by the guidance system it can be used only in a stable anatomical situations (such as non-displaced fractures or pedicular screw placements). The use of better-oriented surgical instrumentation and more than one reference point detection will significantly improve the clinical potential of this method.

Severe bone loss in weight bearing bones is one of the main causes for morbidity in trauma victims. The use of guided bone regeneration in the treatment of such large defects has not yet been studied extensively. The aim of this study was to establish an accurate evaluation system, which will enable quantifying the compatibility of membranes to provide bone regeneration in a large middiaphyseal bone defect. In our longitudinal study on 16 rabbits we examined the new bone formation obtained in the vicinity of critical segmental defects (2.5 times the diameter of the bone) covered with tubular ethyl cellulose membranes. The contralateral limbs with the same bone defect served as the control group which was not treated by membranes. The healing process was followed up for eight weeks.

Bone analysis of the implanted and non-implanted bone defects and adjacent tissues was performed in order to evaluate the total area and the density of the regenerated new bone at the gap area. Computerized X-ray study showed newly formed bone as early as 14 days after membrane implantation within and around the radial defect compared with a typical creation of non-union in the contra-lateral non-implanted defects. The bone formation across the gap progressed until reconstruction of the defect occurred after 6–8 weeks. A slowdown in new bone formation was evident after 6 weeks according to the measurements of area size and density of the formed bone.

A parallel longitudinal histomorphological assessment of the process in the treated and non-treated bone defects was conducted. A characteristic process of osteogenic activity and new bone formation takes place inside the confined space and within the tissues around it. A typical modeling process with lytic changes in the different osteogenic fronts takes place from the second week post-implantation. These histological findings, corresponding with the radiological assessment, were summarized according to a scoring system which was constructed by the authors. The scoring was related to eight different zones which were defined within and around the osteotomy site.

This rabbit model clarifies the mechanism and provides quantification of guided bone regeneration. It can serve as a means to study the accelerated bone formation using different membranes in large segmental weight bearing bone defects.

Introduction: Bone strength is determined by several factors including bone mineral density and the geometrical structure of bone tissue. Plain X-ray is not used regularly for bone mineral density measurements due to different x-ray exposure used for each patient. The different radiation energies have major effects on the optical density of the obtained films. Therefore dual energy X-ray absorptiometry (DEXA) is the golden standard for bone density estimation. However it is relatively expensive and relatively inaccessible.

Objective: To evaluate a new computerized analysis of digitized plain radiographs of the proximal femur to allow the evaluation of bone mineral density in human subjects.

Material and Methods: 14 people hospitalized for proximal femoral fracture had their uninvolved proximal femur BMD estimated with a DEXA in the 5 typical regions defined by the DEXA test. Plain proximal femur radiographs of these patients were taken with a standard wedge and digitized into the computer to generate a digital image. The gray levels in the digital image were analyzed and normalized to yield the mineral content at the 5 regions defined by DEXA. The data obtained were correlated with the DEXA results.

Results: The correlation between BMD (DEXA) and gray level measurement of the proximal femur (R=0.261) was not significant. This correlation was significantly improved after modification of the gray levels to 0.549 (P< 0.032).

Conclusion: This computerized analysis and modification of gray levels in digitized radiographs improved significantly the possibility to evaluate bone mineral density of the proximal femur from plain X-rays.

Objective: The objective of this study was to compare the influence of different hyperthemic processes (autoclave and microwave oven) on the morphologic and thermodynamic properties of collagen.

Summary and Background Data: The current thinking regarding the treatment of human bone tumors is a radical excision, attempting to preserve the function of the limb. An acceptable method for limb preservation is reimplantation of the affected bone after the debridement of gross tumor tissue and sterilization by means of autoclave. This hyperthermic processing technique provides a perfectly sized graft, but it is associated with a decline in the mechanical and biological properties of the bone. A previous study demonstrated that sterilization using a microwave kills all viable cells with a minimal decrease in the mechanical and biological properties of the bone. Possible explanation of this phenomenon is preservation of matrix protein such as collagen. The current study’s goal was to investigate the effect of different hyperthermic treatments on native collagen.

Materials and Methods: In this study we used Heilistat-absorbable collagen sponge (American biomaterials corporation, Plainsboro, NJ 08536). This collagen was divided into three study groups. The first group was processed in the autoclave, the second in a microwave oven and the third which served as the control group received no thermal treatment. The thermodynamic properties of these three groups were checked by Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA). The morphological structure was examined by Scanning Electron Microscope (SEM), Phillips. Accelerating Voltage 30 KV.

Results: Thermodynamic properties: The peak temperature and the amount of energy invested showed similar results in the control group and in the microwave group, and differed from the results of the group treated by autoclave. The graphs of TGA, which represent the weight decrease as a function of heating, were also similar in the microwave group and the control group.

The morphological structure of the collagen, namely, the architectural structure of the material and single fibers, as shown by the SEM in various magnifications (100, 1200, 2500 and 5000), was much more similar when comparing between the control group and the microwave group than in the autoclave processed group.

Conclusion: Hyperthermic treatment using a microwave oven has minimal effect, if any, on the native collagen of bone, causing only minimal damage to the morphological and thermodynamic properties of bone. This observation may explain the biological superiority of the microwave treatment over autoclave treatment of bone.

Background: The Achilles tendon is the strongest and thickest tendon in the human body, it is very commonly injured with significant clinical implications. The treatment of Achilles tendon rupture is a matter of controversy in orthopedics and sports medicine. Surgical repair compared with conservative treatment is debated constantly in the literature, without a conclusive decision. The diagnosis of Achilles tendon rupture is based usually on clinical examination, and may be reinforced by ultrasound or magnetic resonance imaging. The present study has been conducted in order to determine whether an ultrasound examination performed at the time of injury could be useful in deciding how to treat the patient.

Patients: Over a period of 5 years we treated 26 patients who had a clinical presentation of ruptured Achilles tendon with ultrasound diagnosis of either a partial tear or a full tear. Patients who were diagnosed by ultrasound as having a full tendon tear were operated on, and were not included in this study. Eight patients had partial tear of the tendon, six had a tear of the musculotendinous region, and twelve had a proximal tear. All patients were treated by means of a cast or a dressing, with limitation of weight bearing. The follow-up period ranged between six months to three years after the injury, and included up-to-date functional evaluation.

Results: Eighteen patients were available for evaluation. Excellent functional results were reported by five patients, twelve patients reported good results, and one patient complained of a bad result. None of our patients needed delayed surgery, and only one suffered from re-rupture of the tendon during his rehabilitation, and was treated conservatively with good results. No correlation was found between the location of the tear and the functional results.

Conclusions: 1. Ultrasound is an important and accurate tool in the diagnosis of Achilles tendon tear and is helpful in choosing the appropriate treatment. 2. Partial tear of Achilles tendon is not an indication for operative treatment, even when the clinical examination (Thompson test) is positive. The outcome of conservative treatment in this situation is as good or even better than surgical treatment.

Introduction: Cementless hydroxyapatite coated prosthesis are mainly selected for a relatively young and active patient population. Most clinical studies demonstrate excellent osseous integration of the HA coating and good outcome. The clinical follow-up reports of the ABG group suggest excellent results, however we observed an alarming rate of acetabular osteolysis and polyethylene wear which required revision surgery. Thus a comprehensive retrospective evaluation of all operated patients had been conducted.

Patients and Methods: 162 ABG hips were replaced in 148 patients, of them 75 patients were studied and followed-up. Mean age was 56 (range 33–71). 48 patients were women and 27 were men. 8 patients had bilateral hip replacement. Etiology of hip disease varied and included primary osteoarthritis (27 patients – 36%), congenital hip dysplasia (24 patients – 32%), osteonecrosis (12 patients – 16%), ankylosing spondylitis (5 patients – 6.6%), post traumatic arthritis (5 patients – 6.6%) and post-infectious arthrosis (2 patients – 2.6%). Postoperative follow-up period averaged 4 years (range 15–80 months).

Results: The mean postoperative Harris hip score was 89 (range 52–100). 23 patients (30%) reported of modified life activity after surgery, and the majority had resumed their previous occupations.

Complications included 3 early and one late dislocations – one patient required an early cup revision, one patient suffered a fracture of the femur during stem insertion, and 3 patients (4%) had deep vein thrombosis. There was one case of a femoral vein injury and one resolving superficial infection. No deep infections were noted.

13 patients had undergone cup revision due to severe polyethylene wear and periacetabular osteolysis. Of them 5 were diagnosed during this retrospective study and 8 were referred for revision due to clinical symptoms. Thus the revision rate of the entire operated population is 13/162 = 8.0% and 13/75 = 17.3% of the studied patients. The true loosening rate should be between these 2 figures.

In 2 patients the entire cups were removed and revised due to loosening. In 11 patients following the removal of the polyethylene inserts the metal back proved to be stable. In these cases the bone defects were filled-up with bone graft substitute, and a highly cross-linked polyethylene (22 mm head) were cemented into the metal shell. No stems needed revision.

Conclusion: In spite of a relatively high Harris Hip Score and generally good long-term follow-up a high rate of acetbular lysis and polyethylene wear were observed. This observation warrants avoiding the use of the ABG cups until further investigation is performed. A continued clinical and radiographic analysis is required for the entire operated patients. In all cases of polyethylene wear or significant osteolysis revision is indicated.

Mesenchymal Stem Cells (MSCs) are key regulators in senile osteoporosis and in bone formation and regeneration. MSCs are therefore suitable candidates for stem cells mediated gene therapy of bone. Recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) is a highly osteoinductive cytokine, promoting osteogenic differentiation of MSCs.

We hypothesized that genetically engineered MSCs, expressing rhBMP2, can be utilized for targeted cell mediated gene therapy for local and systemic bone disorders and for bone/cartilage tissue engineering. Engineered MSCs expressing rhBMP-2 have both autocrine and paracrine effects enabling the engineered cells to actively participate in bone formation.

We conditionally expressed rhBMP2 (tet-controlled gene expression, tet-off system) in mouse and human mesenchymal stem cells. RhBMP2 expressing clones (tet-off and adeno-BMP2 infected MSCs), spontaneously differentiated into osteogenic cells in vitro and in vivo.

Engineered MSCs were transplanted locally and tracked in vivo in radial segmental defects (regenerating site) and in ectopic muscular and subcutaneous sites (non-regenerating sites). In vitro and in vivo analysis revealed rhBMP2 expression and function, confirmed by RT-PCR, ELISA, western blot, immunohistochemistry and bioassays. Secretion of rhBMP2 in vitro was controlled by tetracycline and resulted in secretion of 1231 ng/24 hours/106 cells.

Quantitative Micro-CT 3-Dimentional reconstruction revealed complete bone regeneration regulated by tetracycline in vivo, indicating the potential of this platform for bone and cartilage tissue engineering. Angiogenesis, a crucial element in tissue engineering, was increased by 10-folds in transplants of rhBMP2 expressing MSCs (tet-off), shown by histomorphometry and MRI analysis (p< 0.05). In order to establish a gene therapy platform for systemic bone disorders, MSCs with tet-controlled rhBMP-2 expression, were injected systemically (iv).

These engineered MSCs were genetically modified in order to achieve homing to the bone marrow. Systemic non invasive tracking of engineered MSCs was achieved by recording topographical bioluminescence derived from luciferase expression detected by a coupled charged CCD imaging camera. For clinical situations that require immuno-isolation of transplanted cells, we developed an additional platform utilizing cell encapsulation technique. Immuno-isolated engineered MSCs, with tet-controlled rhBMP-2 expression, encapsulated with sodium alginate induced bone formation by paracrine effect of secreted rhBMP-2. Finally, we have characterized a novel tissue-engineering platform composed of engineered MSCs and biodegradable polymeric scaffolds, creating a 3D bone tissue in rotating Bioreactors. Our results indicate that engineered MSCs and polymeric scaffolds can be utilized for ex vivo bone tissue engineering. We therefore conclude that genetically engineered MSCs expressing rhBMP-2 under tetracycline control are applicable for: a) local and systemic gene therapy to bone, and b) bone tissue engineering. Our studies should lead to the creation of gene therapy platforms for systemic and local bone diseases in humans and bone/cartilage tissue engineering.

Introduction: Fluoroscopy is routinely used for real-time intra-operative localization of patient anatomy and surgical instrument positioning. Using this radiographic information the orthopedic surgeon inserts different implants into bone. Despite its utility, however, fluoroscopy does have disadvantages. The most notable is potential occupational radiation exposure. Conventional fluoroscopy usually provides only one plane at a time, whereas at least two planes are needed for optimal placement of an implant. By combining a standard C-arm fluoroscopy with computer aided surgical technology, radiation exposure can be eliminated and four different planes can be visualized simultaneously. This study presents data of preliminary clinical experience using this new technology.

Material and methods: The Stealth Station Treatment Guidance Platform System by Medtronic was used. The calibration target was attached to a C-arm fluoroscope. The static reference arc which was attached to the patient and various surgical tools. All with affixed light emitting diodes (LEDs) which were seen by the Infra Red camera. After a short registration process in which the relevant anatomy images were acquired, the C-arm was withdrawn and the entry point to the operated anatomy was determined using the navigation capabilities of the system.

During a period of six months, 31 patients underwent different surgical procedures in which a guided wire was used for: percutaneous fixation of unstable pelvis and hip fractures (13 patients), inserting and locking of an intrameduallry nail (12 patients), inserting pedicular screws (2 patients), or removing foreign-bodies or internal fixations (4 patients). In all cases the placement of the hardware was approved by conventional fluoroscopy as well.

Results: Excellent correlation between the virtual fluoroscopic imaging and live fluoroscopy was observed, thus the placement of the wire in all cases was satisfactory and there was no need to change the position of the wire following the live fluoroscopic confirmation. The number of fluoroscopic buttoning was smaller than the average number in similar surgery using conventional fluoroscopy.

Discussion: According to our preliminary clinical experience it seems that virtual fluoroscopy offers several advantages over conventional fluoroscopy while providing acceptable targeting accuracy. Our impression is that its saves fluoroscopic radiation exposure and improves exactness of the procedure. However, since currently only one reference arc can be detected at a time by the guidance system it can be used only in a stable anatomical situations (such as non-displaced fractures or pedicular screw placements). The use of better-oriented surgical instrumentation and more than one reference point detection will significantly improve the clinical potential of this method.

Background: Osteoarticular disease is the most common complication of brucellosis and has been described in 10–85% of patients. Spondylitis is the most prevalent clinical form, also arthritis, bursitis, tenosynovitis, sacroileitis and osteomyelitis have been also described.

Method: We describe our experience concerning three patients with brucellar prosthetic joint infection in Israel.

Results

Case 1: A 38 year old artist was admitted for revision of total hip replacement due to increased pain accompanied by loosening of the prosthesis. Four years prior admission total hip arthroplasty was performed due to psoriatic arthritis treated by methotrexate. Revision surgery demonstrated necrotic tissue which grew Brucella melitensis. Doxycycline and rifampicin were administered for 12 weeks. Second stage revision was performed on the 6th week of antibiotic therapy with favorable results.

Case 2: A 62 year old Arab male underwent right total knee arthroplasty 4 years prior admission due to osteoarthritis. Past medical history included hip arthritis. A second TKA was performed due to septic arthritis caused by Staphylococcus epidermidis and Acinetobacter baumanii. The first stage of the arthroplasty grew Brucella melitensis.

Antibiotic treatment and second stage revision surgery were followed successfully.

Case 3: A 67 year old Arab male was admitted due to fever, right pelvic and back pain lasting for 6 weeks. Five years prior admission the patient underwent left total knee arthroplasty. Computerized tomography was normal. Following admission severe left knee pain developed. Joint aspirate grew Brucella melitensis. Antibiotic treatment and two stages revision surgery were performed successfully.

In all three cases consumption of unpasteurized dairy products was documented. All three patients had serum brucella antibody titer of 1:1600.

Conclusion: Brucella melitensis should be added to the differential diagnosis of prosthetic joint infection, mainly in the Mediterranean basin and the Arabian Gulf. Only two other cases of brucella prosthetic joint infections were reported involving prosthetic knees.

Background: Osteoporotic tibial fractures may be a challenge both in diagnosis and treatment. The aim of treatment is obtaining joint congruity and normal alignment, joint stability, adequate soft tissue healing and functional range of motion. The goal is prevention of degenerative osteoarthritis. In the majority of cases the treatment of tibial plateau fractures consists of open reduction and internal fixation.

Objectives: The presentation of two aspects of the osteoporotic fracture – the insufficiency fracture and fixation of the fractures by a more appropriate method.

Patients: We present our experience with 7 cases treated during the past 2 years. Two of these cases presented with no story of trauma, normal X-rays and were diagnosed clinically and on CT and bone scanning. The other 5 cases resulted of minor trauma and operative treatment was in order, using a modified fixation technique – a small fragment plate.

Results: The patients suffering from fractures with normal X-rays suffered from insufficiency fractures and were treated conservatively. The patients suffering from depressed, split or comminuted fractures were treated by open reduction and internal fixation with a small fragment plate.

Discussion and Conclusion: Insufficiency fractures often are misdiagnosed as exacerbation of chronic metabolic or inflammatory diseases and a fracture is not suspected until intense augmentation of radionuclide is seen on bone scan. Screening of patients presenting wit non-traumatic knee pain has shown a prevalence insufficiency fractures of the tibial plateau between 3 to 8% of the cases. These cases may be much more common than we commonly presume.

The fractures in need of reduction and fixation of the plateau fracture involve raising the depressed articular fragment, the possible addition of bone graft augmentation and buttressing of the osteochondral fragment with a plate. These buttress plates may hold the cortical rim of the plateau but many times fail in maintaining the reduction of the intra-articular surface of the plateau. This again results in degenerative changes in the joint and pain.

Internal fixation of these fractures with small fragment plates may be a solution to this problem, as demonstrated by the 5 presented cases treated operatively. The plates are smaller in size and are held by more screws, which are more proximal to the articular surface. This way they allow better control and maintenance of the anatomic reduction and in combination with an a-traumatic dissection and less stress shielding effect, result in a low rate of local complications.

We report four patients with unilateral postpartum sacroiliitis presenting with agonising unilateral pain, an elevated ESR, elevated alkaline phosphatase levels, leucocytosis and positive bone scans. The diagnosis of a non-infectious inflammatory cause was supported by the postpartum onset, the response to non-steroidal anti-inflammatory drugs, negative aspiration cultures in two cases and the lack of changes in the sacroiliac joints on long-term follow-up radiographs.

Four cases of osteomyelitis of the pelvis are reported to demonstrate the several clinical syndromes to which this disease can give rise. Extensive surgical drainage and antibiotic treatment led to recovery in all cases.

A consecutive series is reported of 17 patients who underwent early surgical treatment for acetabular or unstable pelvic fractures associated with ipsilateral fractures of the femur. Treatment included external and internal fixation, and required careful consideration of the surgical approach and the positioning of the patient. The multiple injuries sustained by these patients required simultaneous procedures by several surgical teams. All the femoral fractures were internally fixed at the initial operation and eight patients had primary definitive treatment of all their other fractures as well. In nine patients the definitive treatment of their other fractures was delayed for an average of 11 days. There were no deaths, and no serious infections. The long-term morbidity resulted from the associated injuries and not from the pelvic or femoral fractures.

We report two cases of Serratia marcescens infection at the sites of spinal fractures and emphasise the fact that neurological deterioration soon after spinal fracture may be due to acute vertebral osteomyelitis.