Being commonly missed in the clinical practice, Lisfranc injuries can lead to arthritis and long-term complications. There are controversial opinions about the contribution of the main stabilizers of the joint. Moreover, the role of the ligament that connects the medial cuneiform (MC) and the third metatarsal (MT3) is not well investigated. The aim of this study was to investigate the influence of different Lisfranc ligament injuries on CT findings under two specified loads.

Sixteen fresh-frozen human cadaveric lower limbs were embedded in PMMA at mid-shaft of the tibia and placed in a weight-bearing radiolucent frame for CT scanning. All intact specimens were initially scanned under 7.5 kg and 70 kg loads in neutral foot position. A dorsal approach was then used for sequential ligaments cutting: first – the dorsal and the (Lisfranc) interosseous ligaments; second – the plantar ligament between the MC and MT3; third – the plantar Lisfranc ligament between the MC and the MT2. All feet were rescanned after each cutting step under the two loads.

The average distances between MT1 and MT2 in the intact feet under 7.5 kg and 70 kg loads were 0.77 mm and 0.82 mm, whereas between MC and MT2 they were 0.61 mm and 0.80 mm, without any signs of misalignment or dorsal displacement of MT2. A slight increase in the distances MT1-MT2 (0.89 mm; 0.97 mm) and MC-MT2 (0.97 mm; 1.13 mm) was observed after the first disruption of the dorsal and the interosseous ligaments under 7.5 kg and 70 kg loads. A further increase in MT1-MT2 and MC-MT2 distances was registered after the second disruption of the ligament between MC and MT3. The largest distances MT1-MT2 (1.5 mm; 1.95 mm) and MC-MT2 (1.74 mm; 2.35 mm) were measured after the final plantar Lisfranc ligament cut under the two loads. In contrast to the previous two the previous two cuts, misalignment and dorsal displacement of 1.25 mm were seen at this final disrupted stage.

The minimal pathological increase in the distances MT1-MT2 and MC-MT2 is an important indicator for ligamentous Lisfranc injury. Dorsal displacement and misalignment of the second metatarsal in the CT scans identify severe ligamentous Lisfranc injury. The plantar Lisfranc ligament between the medial cuneiform and the second metatarsal seems to be the strongest stabilizer of the Lisfranc joint. Partial lesion of the Lisfranc ligaments requires high clinical suspicion as it can be easily missed.

We retrospectively reviewed 223 cases of supracondylar fractures of elbow treated in our hospital between the years 1996 and 2000. In 30 patients we found some degree of under-reduction of the extension element of the fracture. Twenty-two of them were evaluated close to skeletal maturity. The mean age at fracture was 5.4 years and mean follow-up was 8.2 years. The radiographic remodeling, range of elbow motion and awareness of the patients of functional limitation were evaluated. At the final follow-up17 (77%) of patients have had radiographic loss of humero-condylar angle (5 or more degrees of difference compared to an uninjured side). Eleven (50%) of the patients had limited elbow flexion, and seven (31%) of them were aware of this deficit. Most of under-reductions happened when reduction was attempted in the emergency room, or when displacement was not appreciated and a cast was applied without a reduction attempt.

The conclusions are that the patients that were left to heal with some degree of extension, have had limited end-elbow flexion and may be aware of it. Although only 3 patients felt a minor functional disability at the last follow-up the 10 patients have unsatisfactory results according the Flinn’s criteria for motion restriction. The treating surgeon must be aware of this possible outcome and be more demanding in the reduction of the extension component of a fracture. Otherwise one may expect limited elbow flexion that may be clinically significant. Although the reduction of moderately displaced fractures may seem easy, it is better done in the operating room and not in the emergency room, under general anesthesia and with radiographic control.

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.

Background: Surgical approaches to the acetabular fracture present a challenge for most surgeons. The ilioinguinal approach by Letournel has fundamentally contributed to the successful treatment of such fractures. The current tendency is to minimize the approach while maintaining a proper visual field that allows inspection of fracture fragments and the ability to reduce them. The Stoppa approach is a less invasive anterior intra-pelvic approach that could be combined with a lateral window of the ilioinguinal approach, especially helpful in facilitating the approach to the quadrilateral plate.

Aim: To evaluate the efficacy and safety of the Stoppa approach for the treatment of different types of acetabular fractures.

Patients: Between the years 2004 and 2006, 45 patients with acetabular fractures were operated on using the Stoppa approach. Their age ranged between 14 and 73 (average 42). There were 33 males and 12 females whose fractures were classified as anterior column fractures (21) associated both columns (11) transverse (6), T-shape and other various types. They were consecutively operated in two level 1 trauma centers; in 13 the Stoppa approach was used solely and in the others a combination of the Stoppa approach with an iliac window was employed. Patients were followed for an average of 11.4 months (range 2–36 months), and assessed using the Merle d’Aubigné score.

Results: Visualization of the fracture, reduction and fixation were all feasible through the Stoppa approach. The average length of surgery was 4 hours and an average of intraoperative bleeding was 1086 cc. We were able to achieve excellent reduction in 37 patients and a good reduction in the rest of the cases. Clinical outcomes were good to excellent in 90% of the patients. 3 patients underwent hip arthroplasty due to post traumatic osteoarthritis.

Conclusions: The Stoppa approach in combination with an iliac window offers superb visualization of the quadrilateral plate, anterior column and in some cases the posterior column as well and enables excellent reduction. It is a reasonable replacement for the iliuinguinal approach offering less tissue dissection.

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.

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.

Bone regeneration is a complicate biological process of the skeletal system leading to restoration of the limb function. This process becomes more challenging in a case of critical size defect (CSD) which defined as the smallest defect caused by infection, tumor or trauma that will not heal spontaneously.

A previous study in our lab tested the usage of encapsulating Ethyl Cellulose (Hercules Inc, Wilmington, Del) membrane in CSD as compared to control (no-membrane). The study demonstrated that bone healing was more sufficient in limbs coated with the membrane than the control limbs. Additional approach to the treatment of bone deficiency is the use of multi-potent mesenchymal stem cells (MSC) that are brought into the bone defect in order to induce bone formation.

The objective of this study was to investigate a new polymer formulation in order to produce the best environmental support for adhesion, proliferation and differentiation of MSC.

In this study we found out that with the usage of Polyvinylacetate, PMMC R and PMMC L in PMMC RL PEG 400 [15%], MSC had similar characters to the polystyrene ( a well known ideal platform for MSC). This positive result permitted apparently thanks to creation abilities of:

Hydrogen-bonds between MSC and the partial negative charge on the carboxyl group as well as on the oxygens of the plasticizer that is intertwined within the membrane monomers.

In summary, we have only started to reveal the remarkable potential of using MSC, and there are still many obstacles to overcome. However, applying the findings from this study, namely inserting a membrane coated with MSC into a CSD may become a true biological treatment option.

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: 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: 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.

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: 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: 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.

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.