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.