New Versus Old-How Reliable Is the New OTA/AO Classification for Trochanteric Hip Fractures?

OBJECTIVE: To evaluate the intraobserver and interobserver reliability of the 2018 OTA/AO trochanteric hip fracture (THF) classification compared with the 1983 OTA/AO Muller classification system. To further delineate the reliability of classifying stable and unstable THF using the 2 classification systems. DESIGN: Radiographic observational study. SETTING: Multicenter, one Level 1 and one Level 2 trauma centers. PARTICIPANTS/PATIENTS: Seventy-three radiographic series of patients treated operatively for THF were evaluated by 6 orthopaedic surgeons. INTERVENTION: The OTA/AO THF classification system was applied by each surgeon to 73 cases in 2 independent assessments performed 4 weeks apart: once by the old classification followed by the new 2018 OTA/AO classification. Each radiographic series included lateral hip and anteroposterior initial radiographs. Eight random cases were duplicated in each of the surveys to evaluate the intraobserver reliability. MAIN OUTCOME MEASUREMENTS: Intraobserver and interobserver of the group, subgroup and fracture stability classification determined by the interclass coefficient (ICC) and Cohen kappa values. RESULTS: The interobserver reliability for the group classification (31A1/A2/A3) was moderate using the new classification, whereas substantial agreement was shown using the old classification (0.49 and 0.69, respectively). The reliability of the fracture stability classification was higher using the old classification (0.70 vs. 0.52). Subgroup classifications interobserver agreement was fair for both classification systems, although lower reliability was shown in the old classification (0.34 vs. 0.31). CONCLUSIONS: The new OTA/AO classification has a lower interobserver reliability for THF classification when compared with the old one.

Computer-Generated Radiographic Measurements of Distal Radius Fractures: Does It Help With Decision Making?

PURPOSE: Operative management of distal radius fractures (DRFs) has become increasingly common. Age, activity levels, and comorbid conditions are major factors influencing the treatment decision, although operative indications are still controversial. Radiographic parameters (RPs), such as radial inclination, dorsal tilt, and articular step-off, can provide objective support for effective decision making. However, manual measurement of RPs may be imprecise and subject to inconsistency. To address this problem, we developed custom software of an algorithm to automatically detect and compute 6 common RPs associated with DRF in anteroposterior and lateral radiographs. The aim in this study was to assess the effect of this software on radiographic interobserver variability among orthopedic surgeons. Our hypothesis was that precise and consistent measurement of RPs will improve radiographic interpretation variability among surgeons and, consequently, may aid in clinical decision making. METHODS: Thirty-five radiograph series of DRFs were presented to 9 fellowship-trained hand and orthopedic trauma surgeons. Each case was presented with basic clinical information, together with plain anteroposterior and lateral radiographs. One of the 2 possible treatment options was selected: casting or open reduction with a locking plate. The survey was repeated 3 weeks later, this time with computer-generated RP measurements. Data were analyzed for interobserver and intraobserver variability for both surveys, and the interclass coefficient, kappa value, was calculated. RESULTS: The interobserver reliability (interclass coefficient value) improved from poor to moderate, 0.35 to 0.50, with the provided RP. The average intraobserver interclass coefficient was 0.68. When participants were assessed separately according to their subspecialties (trauma and hand), improved interobserver variability was found as well. CONCLUSIONS: Providing computed RPs to orthopedic surgeons may improve the consistency of the radiographic judgment and influence their clinical decision for the treatment of DRFs. CLINICAL RELEVANCE: Orthopedic surgeons' consistency in the radiographic judgment of DRFs slightly improved by providing automatically calculated radiographic measurements to them.

Initial definitive treatment of open femoral shaft fractures with retrograde nailing - is it safe? A retrospective analysis comparing antegrade to retrograde nailing.

INTRODUCTION: Treatment of severe open femoral fractures with retrograde intramedullary nailing, raises concerns of septic arthritis of the knee due to its intra-articular entrance point. There is little evidence concerning the safety of retrograde femoral nailing (RFN) usage in these cases, and what evidence there is does not necessarily include severe open fractures. Furthermore, the outcome of ballistic injuries treated in this manner and a comparison with antegrade femoral nailing (AFN), is yet to be established. The aim of this study was to examine the outcome of primary retrograde femoral nailing in high-grade open fractures and compare our results with similar fractures treated with AFN. PATIENTS AND METHODS: A retrospective analysis of treated high-grade open femoral fractures, was performed at an academic level one trauma centre between 2006 and 2016. Included were all open femur shaft fractures treated with either RFN or AFN as primary fixation. We analysed both patient groups and compared outcomes including the infection rate, non-union rate and secondary interventions. Presence of knee pain and long-term function, was evaluated using the Short-Form 12 (SF-12) questionnaire. RESULTS: Forty-nine patients with open femoral shaft fractures whose primary treatment was intramedullary nailing (IMN), were included in the cohort. Thirty patients were treated with RFN and 19 with AFN. No septic arthritis of the knee was detected in either group. One patient in the RFN group and two in the AFN had a deep surgical wound infection. Excluding reoperations for locking screw removal due to local irritation, the reoperation rate was 22% with two patients treated for non-union in the RFN group and two in the AFN. When comparing outcome measures, including SF-12 scores and the reported knee pain rates of AFN and RFN groups, no significant differences were observed. CONCLUSION: Our study showed that retrograde femoral nailing as initial definitive treatment in high-grade open femoral shaft fractures, resulted neither in septic arthritis of the knee nor in an unacceptable infection rate. General outcomes regarding complications and reoperations, was similar to antegrade femoral nailing performed in our centre for similar injuries.

Meniscal Entrapment After Tibial Plateau Fracture and Fixation: A Case Report.

CASE: A 40-year-old man presented with limited in range of motion, pain, and tenderness over the medial joint line after an open reduction and internal fixation (ORIF) because of a bicondylar tibial plateau fracture (TPF). The cause of his pain was inconclusive on Magnetic Resonance Image (MRI), so arthroscopy was performed and identified an incarcerated medial meniscus at the fracture site. An osteotomy with medial joint elevation was performed followed by a meniscus release, with excellent results at the 1-year follow-up. CONCLUSION: To our knowledge, this is the first case reporting a trapped/incarcerated meniscus in a healed TPF after ORIF.

Ligamentous Lisfranc injuries: analysis of CT findings under weightbearing.

PURPOSE: The aim of this study was to investigate the influence of different ligamentous Lisfranc injuries on computed tomography (CT) findings under weight-bearing and to emphasize the indications for surgical treatment of their various types. METHODS: Sixteen human cadaveric lower limbs were placed in weight-bearing radiolucent frame for CT scanning. All intact specimens were initially scanned, and then, dorsal approach was used for sequential ligaments cutting of: (1) the dorsal and the interosseous (Lisfranc) ligaments between medical cuneiform (MC) and metatarsal 2 (MT2); (2) the plantar ligament between the MC and MT3; (3) the plantar ligament between MC and MT2. Based on sequential CT scans, the distances MT1-MT2, MC-T2, as well as the alignment and dorsal displacement of MT2 were measured. RESULTS: Slight increase in the distances MT1-MT2 and MC-MT2 was observed after the disruption of the dorsal and the interosseous ligaments. Further increase in MT1-MT2 and MC-MT2 distances was registered after the disruption of the ligament between MC and MT3. The largest distances MT1-MT2 and MC-MT2 were measured after the final plantar ligament cut between MC and MT2. CONCLUSIONS: Unequivocal instability is observed with simultaneous transection of the Lisfranc ligament with both plantar ligaments. On CT used as diagnostic tool, plantar injuries at the basis of the second and the third metatarsal are indirect signs of violation of the ligaments and represent an indication for surgical treatment. When using magnetic resonance imaging as diagnostic tool, a ruptured Lisfranc ligament alone without dislocation does not necessarily need surgical intervention.

Combined approach for intrapelvic abscess drainage among adults.

Obturator internus muscle (OIM) and adductor brevis (AB) abscess occurs rarely in adults. This condition mainly affects children experiencing trauma. This paper presents and discusses a unique case of OIM and AB abscess in an adult male that was treated operatively with a combined surgical approach (modified Stoppa and Smith-Peterson) after multiple failed drainage procedures. CASE: A 23-year-old male underwent reduction and fixation of his right tibiae shaft fracture with an intramedullary nail. After several referrals to the emergency room due to recurrent symptoms of fever and groin pain, he was finally admitted and diagnosed with OIM and AB abscess and fulminant MRSA sepsis. The operative treatment was performed by addressing the abscess with an unusual combined surgical approach (Smith-Peterson and modified Stoppa) for abscess drainage. METHODS: Using PubMed, Google scholar and Hadassah Hebrew University search engines, we conducted a literature search using the following keywords: 'pyomyositis', 'obturator abscess', 'pelvic abscess', and 'pelvic osteomyelitis among children and adults'. Twenty case studies were found (14 children and 6 adults). No cases of combined OIM and AB abscess were found and only one OIM case was reported with methicillin-resistant Staphylococcus (MRSA).

Guided Bone Regeneration with Ammoniomethacrylate-Based Barrier Membranes in a Radial Defect Model.

Large bone defects pose an unsolved challenge for orthopedic surgeons. Our group has previously reported the construction of a barrier membrane made of ammoniomethacrylate copolymer USP (AMCA), which supports the adhesion, proliferation, and osteoblastic differentiation of human mesenchymal stem cells (hMSCs). In this study, we report the use of AMCA membranes to seclude critical segmental defect (~1.0 cm) created in the middle third of rabbit radius and test the efficiency of bone regeneration. Bone regeneration was assessed by radiography, biweekly for 8 weeks. The results were verified by histology and micro-CT at the end of the follow-up. The AMCA membranes were found superior to no treatment in terms of new bone formation in the defect, bone volume, callus surface area normalized to total volume, and the number of bone trabeculae, after eight weeks. Additional factors were then assessed, and these included the addition of simvastatin to the membrane, coating the membrane with human MSC, and a combination of those. The addition of simvastatin to the membranes demonstrated a stronger effect at a similar radiological follow-up. We conclude that AMCA barrier membranes per se and simvastatin delivered in a controlled manner improve bone regeneration outcome.

Suprapatellar nailing of fractures of the tibia.

OBJECTIVE: Intramedullary nailing of tibia fractures via a suprapatellar, transarticular approach with the knee joint in 20-30° of flexion and the use of specific protection tubes to preserve intra-articular structures. INDICATIONS: Extra-articular fractures of the proximal tibia; simple and comminuted fractures of the tibia diaphysis; segmental diaphyseal fractures of the tibia; extra-articular fractures of the distal tibia and fractures with simple intra-articular distal extension; floating knee injuries. CONTRAINDICATIONS: Gustilo grade 3C open fractures of the tibia; severe soft tissue laceration, contamination or infection in the suprapatellar area; ipsilateral knee joint prosthesis; knee arthrodesis; implants blocking the nail entry point. SURGICAL TECHNIQUE: Via a suprapatellar, transarticular approach an intramedullary tibia nail is inserted after anatomical reposition of the tibial fracture with the knee joint in 20-30° of flexion. Use of specific protection tubes to preserve intra-articular structures. The proximal and distal locking configuration depends upon the specific fracture characteristics. RESULTS: In all, 61 patients underwent suprapatellar tibia nailing and were under follow-up at least until fracture union. Twelve patients suffered from an open fracture. A total of 17 patients had a distal third fracture, 8 sustained a proximal third fracture and 36 had a shaft fracture. Follow-up focused on patients with distal fractures; 6/17 patients sustained open fractures. Average time to union was 9 weeks. One fracture did not heal and required exchange nailing. Two patients complained about anterior knee pain. Functionally, full range of motion was regained in all patients.

Outcome of femoral fractures in poliomyelitis patients.

BACKGROUND AND PURPOSE: As patients who were afflicted with poliomyelitis during the outbreaks in the past are aging, lower extremity osteoporotic fractures are becoming more frequent. Fixation in deformed, porotic bone, coupled with muscle weakness and imbalance creates a unique challenge when treating these fractures as does their reduced rehabilitation potential. The aim of this study was to investigate the outcome of femoral fractures in surviving poliomyelitis patients. PATIENTS AND METHODS: Sixty-five patients with 74 femoral fractures were treated between 1990 and 2014. Clinical outcome was assessed using the Parkland and Palmer mobility score, and quality-of-life was assessed using the SF-12® score. RESULTS: Some 84% of the fractures were a result of low-energy mechanisms and occurred in the polio-affected limbs, but nonaffected limbs were also injured owing to low-energy mechanisms in all cases. Fifty-seven fractures were treated operatively. There were nine re-operations (16%), including implant removals, nonunion, peri-implant fractures, and malunion. Some 60% of the patients did not regain their previous ambulatory capacity. Post-operative weight-bearing status did not correlate with the final functional outcome. CONCLUSIONS: Polio patients with femoral fractures have a guarded prognosis for regaining their pre-injury ambulatory capacity. A higher re-operation rate than that with "normal" osteoporotic fractures is expected.

Robotic assisted fixation of sacral fractures: A pilot study.

OBJECTIVES: Sacral fractures that require fixation are a challenge for the orthopaedic surgeon. Due to anatomical consideration, implant insertion is not risk free, and requires a steep learning curve. A robotic system has been successfully used in pedicle screws insertion and can be also used for iliosacral screws. The aim of the study was to demonstrate the use of the robot in the treatment of unstable sacral fractures. DESIGN: Retrospective case series. SETTING: An academic level I trauma center. PATIENTS: Fourteen patients with sacral fractures were eligible for robotic assisted treatment. These included 9 high-energy fractures, 4 osteoporotic fractures, and 1 pathological fracture. INTERVENTION: Fixation constructs included iliosacral screws, transiliac screws, lumbopelvic fixation, sacroplasty, or a combination of the above techniques. A Renaissance robot was mounted on a multidirectional bridge that was attached to the patients spine and implant trajectories were planned either on preoperative or intraoperative 3D scans. Guide wires were inserted percutaneously and screws were placed subsequently. MAIN OUTCOME MEASUREMENTS: Accuracy of implant placement, operating room and fluoroscopy time. RESULTS: Mean patient age was 36 (17-84), and number of screws, including iliosacral and pedicular ranged 1-14 per patient (average 4.25). Mean operative time was 150 minutes (range 90-300). Average fluoroscopic time was 18 seconds (7-42) for 2D and 40 seconds (12-72) for 3D imaging. All fractures healed, no hardware failure was observed. All hardware was always within bony confines, and no procedure-related neurological deficits were observed. CONCLUSION: Robotic assisted fixation of sacral fracture is a safe and reproduceable method, allowing precise and accurate implant placement.

[FLUOROSCOPIC BASED NAVIGATION IN ORTHOPAEDIC TRAUMA - A REVIEW OF A LARGE CENTER'S EXPERIENCE].

INTRODUCTION: Computer Assisted Orthopaedic Surgery (CAOS) was introduced in the late 1990's and early 2000's. Since then its application in orthopaedic trauma has been utilized mainly as augmented fluoroscopy for intraoperative navigation. From 2010 our center implemented an advanced system allowing further expansion of this technology. AIMS: The aim of this study was to describe the experience with an advanced fluoroscopic based CAOS system in our center. METHODS: The BrainLabTM Trauma 3.0 utilizes a handheld fluoroscope tracker, enables tracking of two anatomical objects and intraoperative planning. We implemented this system for the performance of 126 navigated procedures between the years 2011-2014. The procedures included 58 cases of navigated hip fracture pinning, 9 plate navigation for distal femoral fractures, 19 iliosacral screw insertions, 20 femoral fracture reductions, and 12 other procedures (acetabular screws, osteotomies etc). RESULTS: The mean age of patients was 52 years (range 16-82 years); 46 male and 80 female patients. The mean operating room time was 157 minutes (range 70 to 470 minutes). The average radiation required was 550 rad cm2 (~30 sec fluoroscopic time). Overall estimated additional OR time was estimated as 10-15 minutes for hip pinning, 15-20 minutes for pelvic iliosacral screws and 30-45 minutes of additional OR time for femur fracture reduction for length and rotation. In 5% of cases (6 patients), navigation was aborted due to technical reasons. No misplaced hardware due to the use of navigation was documented. CONCLUSIONS: CAOS is a powerful tool in trauma surgery with 95% success rate, with a reasonable added burden time. Although 3D navigation may be more useful in the pelvis, even two-dimensional navigation increases precision and implant placement. Femoral fracture reduction for accurate length and rotation control is solely enabled by CAOS. In the future, more time efficient and user-friendly systems will enable widespread use of these technologies in orthopaedic trauma.

Use of fully threaded cannulated screws decreases femoral neck shortening after fixation of femoral neck fractures.

BACKGROUND: Femoral neck fractures (FNF) are becoming increasingly common as population ages. Nondisplaced fractures are commonly treated by cancellous, parallel placed, partially threaded cannulated screws (PTS). This allows controlled fracture impaction. However, sliding implants can lead to femoral neck shortening (FNS) that has been shown to be correlated with reduced quality of life and impaired gait pattern. Recently, in our institution we have changed the fixation of FNF to fully threaded screws (FTS) with or without an additional partially threaded screw in order to minimize this phenomenon. The aim of this study was to compare the FNS in patients treated with FTS as compared with our historical controls treated with PTS. PATIENTS AND METHODS: Between 2014 and 2016, 38 patients with FNF were treated with FTS. Out of the 38, 24 were available for radiographic follow-up. 41 patients treated previously with PTS were available as a control group. Radiographic analysis was performed to assess the FNF in three vectors: Horizontal (X), Vertical (Y) and overall (Z) according to the neck-shaft angle. RESULTS: Time for admission to surgery was longer in the PTS group (p = 0.04). Patient demographics and major complication rates were similar in the two patient groups. Average FNS in the X axis was significantly smaller in the FTS group than in the PTS group (2.8 ± 3.6 vs 7.6 ± 4.2 mm, p < 0.01) as well as the Y axis (1.2 ± 2.6 vs 4.9 ± 4.2 mm, p < 0.01) and thus also decreased overall Z shortening (2.3 ± 3.5 vs 6.23 ± 4.5 mm, p < 0.01). There was a tendency towards a more valgus reduction in the PTS (137° vs 134°, p = 0.08). There was a significantly smaller number of FTS patients with moderate (5-10 mm) or severe (> 10 mm) FNS. Screw pull-out > 5 mm occurred in 17/41 patients in the PTS but none in the FTS group (p < 0.01). CONCLUSION: This study proves that use of FTS improves the radiographic results following FNF fixation using cannulated screws.

Radiographic markers for measuring tibial rotation based on CT-reconstructed radiographs: an accuracy and feasibility study.

OBJECTIVES: Malreduction in the axial plane (malrotation) following tibial fracture surgery is often undiagnosed. A few clinical and radiographic methods have been proposed for measuring tibial rotation intraoperatively, yet have failed to match the accuracy of computed tomography (CT). The aim of this study was to develop radiographic tools for future intraoperative assessment of the tibial shaft rotation profile. METHODS: The setting was a laboratory computerized analysis. Twenty lower limb CT scans were used to construct a three-dimensional (3D) model using AMIRA© software. A virtual 3D cylinder was implanted in the posterior condylar line and in the transmalleolar axis. The 3D models were used to simulate four standard knee and ankle plain radiographs. On each radiograph, four landmarks were depicted by two observers and their relation with the cylinder was measured and analyzed for accuracy and reproducibility. A cadaveric lower leg was implanted with two Kirschner wires. A CT scan was performed in addition to 2D fluoroscopy. The simulated radiographs and the fluoroscopy were compared for accuracy. RESULTS: Measurement of the landmarks showed reliability in most of the knee anteroposterior and ankle mortise radiographs (coefficients of variation < 0.01 and = 0.01) respectively. Cadaveric measurement of the landmarks using real fluoroscopy and simulated radiographs were similar. CONCLUSIONS: To date, no reliable and common methods have been reported for the evaluation of tibial axial rotation. We propose a model in which simple radiographic landmarks can be used to calculate a 3D coordinate system that accurately assesses the axial rotation angle of the tibial shaft.

Cigarette Smoking Is Associated with a Lower Concentration of CD105(+) Bone Marrow Progenitor Cells.

Cigarette smoking is associated with musculoskeletal degenerative disorders, delayed fracture healing, and nonunion. Bone marrow progenitor cells (BMPCs), known to express CD105, are important in local trophic and immunomodulatory activity and central to musculoskeletal healing/regeneration. We hypothesized that smoking is associated with lower levels of BMPC. Iliac bone marrow samples were collected from individuals aged 18-65 years during the first steps of pelvic surgery, under IRB approval with informed consent. Patients with active infectious or neoplastic disease, a history of cytotoxic or radiation therapy, primary or secondary metabolic bone disease, or bone marrow dysfunction were excluded. Separation process purity and the number of BMPCs recovered were assessed with FACS. BMPC populations in self-reported smokers and nonsmokers were compared using the two-tailed t-test. 13 smokers and 13 nonsmokers of comparable age and gender were included. The average concentration of BMPCs was 3.52 × 10(5)/mL ± 2.45 × 10(5)/mL for nonsmokers versus 1.31 × 10(5)/mL ± 1.61 × 10(5)/mL for smokers (t = 3.2, P = 0.004). This suggests that cigarette smoking is linked to a significant decrease in the concentration of BMPCs, which may contribute to the reduced regenerative capacity of smokers, with implications for musculoskeletal maintenance and repair.

Outcome of proximal femoral fractures caused by cycling in the young and mid-aged.

BACKGROUND: Cycling is gaining more popularity both as a sport, on and off-road and also as a means of commute. Cycling accidents harbour significant injury risks including fractures. Proximal femoral fractures are uncommonly associated with cycling in the young adult population. The purpose of this study is to describe this unique pattern of injury as well as the outcome of proximal femoral fractures caused by cycling in the young to mid age population. STUDY DESIGN: retrospective cohort study. 23 fractures in 22 patients were available for analysis. 11 were femoral neck fractures, with six displaced ones, and the rest trochanteric fractures. 21 patients were male patients, and the average age was 42 (range 27-60). All patients but two were operated within 24 h from admission. Radiographic analysis included reduction quality, fracture classification and arthritic changes. Clinical outcome was measured using SF-12 and Oxford hip scores. RESULTS: All fractures healed. Two patients with displaced femoral neck fractures developed avascular necrosis requiring arthroplasty. One patient developed an AVN 2 years after a stable trochanteric fracture but did not require an arthroplasty as of yet. Eight patients required hardware removal due to symptoms. 77% of patients had resumed cycling at the pre-injury level. Mean SF-12 score was 47.1 ± 11.7 for the physical component and 53.7 ± 6.3 for the mental component. Mean oxford hip score as was 40.1 ± 12.2. Radiographic analysis revealed good to acceptable reduction quality. Fracture type, age, cycling type and reduction were not significantly associated with outcome. CONCLUSION: Proximal femoral fractures caused by cycling in young to mid-aged adults are an emerging pattern of injury. Overall favourable result can be expected in the majority of cases, with displaced femoral neck fractures having a risk for AVN. Further delineation of the exact cause for this phenomenon is required with possible intervention for injury prevention.

Outcome of delayed primary internal fixation of distal radius fractures: a comparative study.

INTRODUCTION AND AIM: Operative fixation of distal radius fractures using fixed-angle devices has become increasingly common. Although good to excellent results have been reported in acute fractures, little is currently known regarding the fixation of healing displaced distal radius fractures that were presented late. The aim of this study was to evaluate the results of internal fixation of distal radius fractures presented late (>21 days) as compared with an acute-care control group. METHODS: Forty patients operated on for displaced distal radius fractures, presenting more than 21 days after injury (delayed treatment (DT) group), were compared with 75 age-matched controls with acute fracture repair (≤21 days). The same surgical approach was used in both groups, together with dorsal soft-tissue and brachioradialis release. No osteotomy was required. Direct and indirect reduction aids were used. A fixed-angle device (DVR; Biomet Inc., Warsaw, IN, USA) was used in both groups. Mean follow-up was 3.4 years. Quick DASH (Disabilities of the Arm, Shoulder and Hand) and Short Form 12 scores were used to evaluate outcome, as well as radiographic analysis for Arbeitsgemeinschaft für Osteosynthesefragen(AO)/Orthopaedic Trauma Association(OTA) classification, volar tilt, radial inclination and radial length. RESULTS: Average age was 53 years in both groups and male to female (M/F) ratio was similar in the study groups. Mean time to surgery was 30 days in the DT group and 8 days in the control group. There were significantly more type C (91.5% vs. 67.5%) fractures in the control group. The average quick DASH score was 27.1 in the DT group as compared with 6.3 in the control group (p<0.03); however, when controlling for two outlier cases with complications (hardware irritation and a sensory neuropathy) there was no significant difference. Volar tilt, radial inclination and length were similar in both groups and were within normal anatomical values. CONCLUSIONS: Delayed primary operative fixation of displaced unstable distal radial fractures is a viable option for cases that were presented late, with predictable, favourable results. Neither extensile approaches nor formal osteotomies are required.

Can a partial volume edge effect reduction algorithm improve the repeatability of subject-specific finite element models of femurs obtained from CT data?

The reliability of patient-specific finite element (FE) modelling is dependent on the ability to provide repeatable analyses. Differences of inter-operator generated grids can produce variability in strain and stress readings at a desired location, which are magnified at the surface of the model as a result of the partial volume edge effects (PVEEs). In this study, a new approach is introduced based on an in-house developed algorithm which adjusts the location of the model's surface nodes to a consistent predefined threshold Hounsfield unit value. Three cadaveric human femora specimens were CT scanned, and surface models were created after a semi-automatic segmentation by three different experienced operators. A FE analysis was conducted for each model, with and without applying the surface-adjustment algorithm (a total of 18 models), implementing identical boundary conditions. Maximum principal strain and stress and spatial coordinates were probed at six equivalent surface nodes from the six generated models for each of the three specimens at locations commonly utilised for experimental strain guage measurement validation. A Wilcoxon signed-ranks test was conducted to determine inter-operator variability and the impact of the PVEE-adjustment algorithm. The average inter-operator difference in stress values was significantly reduced after applying the adjustment algorithm (before: 3.32 ± 4.35 MPa, after: 1.47 ± 1.77 MPa, p = 0.025). Strain values were found to be less sensitive to inter-operative variability (p = 0.286). In summary, the new approach as presented in this study may provide a means to improve the repeatability of subject-specific FE models of bone obtained from CT data.

Computerized navigation for length and rotation control in femoral fractures: a preliminary clinical study.

OBJECTIVE: Operative treatment of femoral fractures yields a predictably high union rate, but residual malrotation and leg length discrepancy remain a clinically significant problem. The aim of this study was to determine the safety and efficacy of using computerized navigation in controlling the length and rotation in femoral fracture surgery. DESIGN: Prospective consecutive case series of 16 skeletally mature patients with femoral fractures undergoing surgical fixation; 14 were fixed with intramedullary nails and 2 with plates. SETTING: An Academic Level I trauma center. INTERVENTION: Computerized navigation was used to determine the length and rotation of the operated extremity as compared with the intact healthy contralateral side. MAIN OUTCOME MEASURE: All patients underwent postoperative computed tomography scanogram for determining the length and rotation. RESULTS: All fractures healed. Mean rotational difference between the treated and nontreated sides was 3.45 degrees (range, 0-7.7 degrees). Mean length difference between the 2 extremities as calculated by the computed tomography scan was 5.83 mm (range, 0-13 mm). Additional operative time required for computerized navigation was measured in 2 of the cases and totaled ∼30-35 min/case. CONCLUSION: Computerized navigation was accurate and precise at restoring femoral length and rotation during femoral fracture fixation when the intact contralateral femur was used for reference. Further, large-scale randomized studies are required. Additionally, improvements aimed at decreasing operative time and improving user interface of these systems are recommended. LEVEL OF EVIDENCE: Therapeutic level IV. See instructions for authors for a complete description of the levels of evidence.

Stem cell-based therapy for prevention of delayed fracture union: a randomized and prospective preliminary study.

Distal tibial fractures tend towards delayed- or nonunion. The purpose of this study was to evaluate the safety and efficacy of early minimally invasive intervention (MII) in the treatment of these fractures. A total 24 consecutive patients who underwent operative treatment for distal tibial fractures were randomized into a control and an intervention group. MII entailed aspirating iliac crest bone marrow and peripheral blood, yielding mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) respectively, that were mixed with demineralized bone matrix (DBM) and injected under fluoroscopic control into the fracture site. No complications occurred in either group. The median time to union was 1.5 months in the MII group and 3 months in the control group. MII was found to be a safe and efficient procedure.

Outcome of angiographic embolisation for unstable pelvic ring injuries: Factors predicting success.

INTRODUCTION: Angiographic embolisation (AE) is a successful treatment for haemodynamically unstable pelvic ring injuries. However, recent evidence has shown a significant complication rate following AE together with a lower success rate than previously reported. The aim of the current study was to review and indentify the factors predicting success or failure of AE. PATIENTS AND METHODS: 651 patients with high energy (ISS>16) pelvic ring injuries were treated in our institution between the years 1997 and 2009. Mean patient age was 37 (range 5-89) years, and the average ISS 33.4 (range 16-66). Patients' information was collected from the institution's trauma registry as well as from the patient's medical chart and radiographs. Data included age, ISS, length of stay, ICU stay, initial blood pressure and pulse, blood products consumption, blood creatinine levels, fracture type and treatment, embolisation details, complications and mortality. 61 patients (9.3%) underwent urgent angiography due to haemodynamic instability. Angiography was positive (PA) in 38 patients (62.3%) and was negative for haemorrhage (NA) in the remaining 23 (37.7%). RESULTS: Ten patients required a branch vessel embolisation while 17 patients required major vessel embolisation, 11 required bilateral internal iliac embolisation and three patients underwent multiple vessel embolisation. Overall mortality rate was 26%. 32 patients required surgical intervention for pelvic ring stabilisation. Significant reduction in blood transfusion was seen in patients with an APC fracture type following AE. No significant correlation was found between fracture type and mortality. Multiple vessel embolisations were associated with increased surgical complications and mortality. DISCUSSION: Angiographic embolisation provides a reasonable option for haemodynamically unstable pelvic ring injured patients with an acceptable outcome, supporting previously reported literature. Patients with unstable APC type pelvic fracture may benefit the most from early angiographic embolisation. Patients requiring multiple vessel embolisation have a guarded outcome.