Proximal Fracture Fragment Research Articles

Omega Plate Fixation of Comminuted Olecranon Fractures: Technique and Case Series.

Fixation of olecranon fractures, especially those with minimal proximal bone and those that present with significant comminution, can be technically challenging. Current open reduction and internal fixation (ORIF) methods, such as tension band wire (TBW) constructs, plate fixation (PF), and intramedullary screws (IMSF), have demonstrated high rates of reoperation and symptomatic implants. We present the omega plate technique, which utilizes a mini-fragment plate passed under the triceps tendon insertion, allowing maximal implant surface area contact with small, proximal olecranon fracture fragments. The mini-fragment plate is not placed on the dorsal subcutaneous border of the ulna, which allows it to capture medial and lateral fragments of cortical comminution and may contribute to less soft tissue irritation.

Is stability of femoral neck fractures in the inverted triangle configuration related to the angle between the fracture line and the cannulated compression screws? A finite element analysis

Purpose Currently, treating femoral neck fractures (FNFs) with the inverted triangle configuration requires alignment between the femoral neck’s long axis and the axis of cannulated compression screws (CCS). To address whether the ‘parallel’ alignment is the most effective approach for fractures with varying Pauwels angles, we employed finite element analysis (FEA) to investigate how different angles between fracture line and CCS affect stability, based on various Pauwels angles. This study aims to offer improved guidance for treating FNFs with the inverted triangle configuration. Methods FNF models with Pauwels angles of 40°, 50°, 60°, and 70° were developed. The CCS were positioned in an inverted triangle configuration based on the angle between the fracture line and CCS. Using FEA, we compared the biomechanical properties of each model to evaluate the stability by evaluating five key parameters: maximal stress in the proximal femoral fracture fragment (MPFS) and implants (MIS), maximal displacement of the bone (MBD) and implants (MID), and maximal relative displacement of the fragments (MRD). Results For Pauwels angles of 40°, 50°, 60°, and 70° across different FNF models, various parameters exhibited similar results. The MPFS showed an upward trend with a decrease in the angle, whereas the MIS, MBD, MID, and MRD all exhibited downward trends. Conclusion The FEA results suggest that decreasing the angle between the fracture line and the CCS for the treatment of FNF can increase the tension resistance of the model, thus increasing the model’s stability.

Functional Outcome of Inter-Trochanteric and Sub-Trochanteric Fracture Femur Treated with Proximal Femur Nail Antirotation-II

Intertrochanteric femoral fractures are of great interest all around the world. They are the most often performed fracture type, and the high expense of treatment required following injury has made them a critical health resource concern. A higher predisposition towards Intertrochanteric fracture is observed in females than males due to osteoporosis A substantial demand is placed on the implanted hardware, as the subtrochanteric region of the femur experiences mechanical forces several multiples of the patient’s weight.The primary objective of this study was to evaluate the functional result of inter- and sub-trochanteric femur fractures treated with Proximal Femur Nail Antirotation-II. To improve the rotational stability of the proximal fracture fragment, the trochanteric fixation nail (TFN) was designed. To lessen bone tension at the isthmus, the diameter of the distal tip of the nail was lowered. The research was carried out in the Department of Orthopaedics, Krishna Institute of Medical Sciences, Karad. The research was carried out between June 2019 and June 2021. The Department of Ethics of Krishna Institute of Medical Sciences, Deemed to be University Karad, granted the ethics committee permission. There were 60 individuals in the research who had intertrochanteric and subtrochanteric femur fractures. After receiving informed written consent in the specified way, all participants were included. In summary, PFN A-II is a stable, biomechanically acceptable implant with a clear advantage over other implants for treating stable and unstable intertrochanteric fractures, particularly those in the elderly, and linked with osteoporotic bone. The benefits of the PFN A-II are noticeable with the right surgical approach, with a bare minimum complication rate.

The Biomechanical Performance of Different Plate Fixation Configurations to Repair Vancouver Type C Periprosthetic Femur Fractures

Objectives The incidence of femoral periprosthetic fractures (PPF) is rising. Vancouver type C PPFs compromise the majority type of fracture associated with high complication rates. The complexity of Vancouver C-type PPFs lies in the presence of the femoral stem in the proximal fracture fragment. This study compares the biomechanical performance of four plate fixation configurations to repair Vancouver type C periprosthetic femur fractures. Methods Six large adult 4th generation biomechanical low-density femur Sawbones instrumented with cemented femoral stems were used to conduct this study. A comminuted Vancouver-type C PPF was simulated and fixed with a plate. Four proximal fragment construct configurations were studied with combinations of unicortical screws, bicortical screws, and cerclage cable fixation. Constructs were loaded in axial compression and four-point bending, and the stiffness was calculated. Results Constructs with bicortical screw fixation had significantly greater stiffness than those with unicortical screw and cerclage cable fixation in axial and four-point bending loads. Constructs with cerclage cable and unicortical screw fixation had greater stiffness than ones with unicortical screw fixation. Conclusion Using bicortical screws in the proximal construct of Vancouver type C PPFs increases construct stiffness in axial and bending loads. Though controversial, using cerclage cables might have a place for construct augmentation when using only unicortical screws or a combination of unicortical and bicortical screws.

Biomechanical effects of internal fixation with self-lock compression anti-rotation blade for Pauwels type III femoral neck fractures: a comparative finite element analysis

BackgroundSelf-lock compression anti-rotation blade (SCAB) is a novel internal fixation implant for femoral neck fractures (FNF). We conducted this finite element analysis study to evaluate the biomechanical performances of SCAB combined with a cannulated screw for fixation of Pauwels type III FNF.MethodsThree finite element models of Pauwels type III FNF treated with various internal fixations were established: a: the inverted triangular parallel cannulated screw (3CS) model, b: the biplane double-supported screw fixation (BDSF) model, c: the SCAB combined with a cannulated screw model. Displacement and Von Mises stress of femurs and internal fixations under increasing loads as well as the average stress on fracture surfaces and maximum displacements on the X and Z axis of proximal fracture fragments at maximum load were measured and compared.ResultThe SCAB-based internal fixation exhibited superior biomechanical performances compared with 3CS and BDSF configurations, as the former resulted in lower parameters including displacement of the femur, Von Mises stress of internal fixation, stress on fracture surfaces as well as X and Z axis displacement of fracture fragments.ConclusionInternal fixation using SCAB combined with a cannulated screw for Pauwels type III FNFs shows enough stability, with satisfied resistance to varus and shearing forces, which may provide a new option for the treatment of FNFs.

Repair of a calcaneal fracture with a combination of internal and external fixation in a calf.

A 6-day-old male Japanese Black calf presented with a transverse fracture of the left calcaneus. In calcaneal fractures, traction of the gastrocnemius muscle causes substantial displacement of the proximal fracture fragment; therefore, external fixation alone is prone to failure of fusion or deformed fusion. Furthermore, internal fixation alone may result in refracture due to the high load on the implant. Therefore, internal and external fixation were used to treat the fracture. Bone fusion was observed on postoperative day 50; the wire was removed on postoperative day 90. Radiographic examination at 4 months postoperatively revealed that the bone had fused in normal alignment. Therefore, a good prognosis can be expected for calcaneal fractures treated with combined internal and external fixation.

Finite element comparative analysis of three different internal fixation methods in the treatment of Pauwels type III femoral neck fractures

BackgroundComparison of 4 cannulated lag screws (3 inverted triangular cannulated screws + anti-rotating screws;4 CLS), dynamic hip screws + derotational screws (DHS + DS), and femoral neck fixation system (FNS) in the treatment of Biomechanical properties of middle-aged Pauwels type III femoral neck fractures.MethodsThe femur CT data of a healthy young volunteer was selected and imported into Mimics software to construct a three-dimensional model of a normal femur. Pauwels type III femoral neck fractures were simulated according to the 70° fracture line. Use Geomagic and SolidWorks software to optimize and build CLS, DHS + DS, and FNS fracture internal fixation models. Finally, Ansys software was used to analyze the stress distribution, peak value, and maximum displacement of the proximal fracture fragment and internal fixation; the displacement distribution, and peak value of the fracture surface at the fracture end.Results① The stress peaks of the proximal fracture fragments in the three groups were concentrated near the femoral calcar. The peak stress of the FNS group was the largest, and the DHS + DS group was the smallest. ②The displacement of the fracture fragments was all located at the top of the femur. The peak displacement of the FNS group was the largest, and the DHS + DS group was the smallest. ③ The internal fixation stress of the three groups is concentrated in the middle part of the device. The stress distribution of the first two groups of models is more uniform than that of FNS. The peak stress of FNS is the largest and the CLS is the smallest. ④ The internal fixed displacements are all located at the top of the model. The peak displacement of the CLS is the largest, and the DHS + DS is the smallest. ⑤ The displacement of the fracture surface is in the upper part of the fractured end. The peak displacement of the FNS group was the largest, and the DHS + DS group was the smallest.ConclusionCompared with the other two internal fixation methods, dynamic hip screw + derotational screw (DHS + DS) showed good biomechanical stability. When Pauwels type III femoral neck fracture occurs in young adults, DHS + DS can be given priority as the preferred treatment for this type of fracture.

A Case Series of Bosworth Fracture-Dislocations and Review of 129 Reported Cases.

Bosworth fracture dislocations of the ankle are rare injuries of the ankle caused by extreme external rotation of the supinated foot where the proximal fibula fracture fragment is posteriorly dislocated and entrapped behind the posterior-lateral ridge of the tibia. This case series aims to document three such cases treated in our institution over a nine year period. We also provide a review of 129 cases in the existing literature. Medical records and relevant radiographs for each patient were analysed and collected from the time of presentation till the point of latest follow-up. During each clinic visit, all physical exam findings as well as all complications were recorded. The American Foot and Ankle Society (AOFAS) Hindfoot score was also tabulated for each patient at the point of latest review. Closed reduction was unsuccessful in all three patients, and all required open reduction. One patient had an uncomplicated recovery whilst the remaining two suffered significant soft tissue complications. One patient suffered severe soft tissue swelling preventing primary closure at the time of surgery, whilst another suffered post-operative wound dehiscence and infection. Eventually all fractures healed, and all three patients obtained satisfactory AOFAS scores. The diagnosis of Bosworth fracture dislocations of the ankle is often delayed or missed, due to its rare occurrence. Closed reduction is often unsuccessful, and early open reduction is required to avoid poor clinical outcomes due to severe soft tissue damage or even compartment syndrome.

Application of anatomically contoured intramedullary interlocking nailing for fixation of femoral diaphyseal fractures in dogs

The study was conducted on 10 client-owned dogs of either sex presented for fixation of femoral diaphyseal fractures. After thorough clinical, orthopaedic and radiographic examinations, the patients were subjected to application of specially-designed anatomically contoured intramedullary interlocking nailing (ACIILN) for fixation of fractures. All the fractures were closed and involved mid (n=9) to slightly distal (n=1) diaphysis. The diameter of used ACIILN ranged from 5–7 mm and the length from 11–15 cm. All the ACIILN were applied in static fashion with at least 2 screws each in both proximal and distal fracture fragments. The duration of surgery for application of ACIILN ranged from 35–75 min. The technique was found to be moderately difficult with extent of tissue manipulation in the category of low to moderate. Pain and inflammation decreased gradually in all the cases in an anticipated manner.With gradual improvement in weight-bearing capability, the limb function was restored in all cases quiet fast in the postoperative period. More amount of the callus formed over medial and caudal surfaces indicating less amount of stability at these surfaces. Anatomically contoured intramedullary interlocking nailing technique provided clinically viable fracture fixation technique resulting into early limb function.

Risk Factors for Loss of Reduction After Open Reduction and Internal Fixation of Isolated Olecranon Fractures in Adults.

We sought to determine whether any relevant patient, fracture, surgical, or postoperative characteristics are associated with loss of reduction after plate fixation of isolated olecranon fractures in adults. Patients who underwent open reduction and internal fixation of an olecranon fracture at our institution over an 11-year period were analyzed. Electronic patient charts and radiographic images were reviewed to gather patient, fracture, surgical, and postoperative data. Statistical analysis to explore the differences between groups was performed. Seven of 96 patients experienced a loss of fracture reduction diagnosed at a median of 19 days after their initial surgery (range: 4-116 days). The radiographic mode of failure of all patients who lost reduction was proximal migration of the proximal fracture fragment with or without implant failure. The group that lost reduction had a significantly smaller proximal fragment (14.2 vs 18.6 mm), a higher incidence of malreduction with a persistent articular step-off greater than 2 mm (6/7 vs 14/89), a greater distance between the most proximal screw and the olecranon tip (19.8 vs 13.5 mm), a higher proportion of constructs with screws placed outside of the primary plate (4/7 vs 14/89), and a higher proportion of patients that were not immobilized postoperatively (3/7 vs 8/89). Our results suggest anatomical reduction at the articular surface and adequate fixation of the proximal fragment are key factors in maintenance of reduction, with smaller proximal fragments being at higher risk for failure. A period of postoperative immobilization may decrease the risk of loss of reduction.

Biomechanical analysis of two medial buttress plate fixation methods to treat Pauwels type III femoral neck fractures

BackgroundFemoral neck fractures in young people are usually Pauwels Type III fractures. The common treatment method are multiple parallel cannulated screws or dynamic hip screw sliding compression fixation. Due to the huge shear stress, the rate of complications such as femoral head necrosis and nonunion is still high after treatment. The aim of our study was to compare the stabilities of two fixation methods in fixating pauwels type III femoral neck fractures.MethodsAll biomimetic fracture samples are fixed with three cannulated screws combined with a medial buttress plate. There were two fixation groups for the buttress plate and proximal fracture fragment: Group A, long screw (40 mm); Group B, short screw (6 mm). Samples were subjected to electrical strain measurement under a load of 500 N, axial stiffness was measured, and then the samples were axially loaded until failure. More than 5 mm of displacement or synthetic bone fracture was considered as construct failure.ResultsThere were no significant differences in failure load (P = 0.669), stiffness (P = 0.842), or strain distribution (P > 0.05) between the two groups.ConclusionsUnicortical short screws can provide the same stability as long screws for Pauwels Type III Femoral Neck Fractures.

Biomechanical Comparison of Dual and Posterior Locking Plates in an Ex Vivo Comminuted Olecranon Fracture Model

Comminuted olecranon fractures are commonly fixed with posterior locking plates (PLPs). Though biomechanically validated, this method comes with risks of symptomatic implant prominence and wound breakdown. Dual locking plates (DLPs) placed on the medial and lateral surfaces of the olecranon theoretically avoid these risks and allow for fixation of proximal fracture fragments in multiple planes. A biomechanical comparison of DLP and PLP fixation would help to validate the use of DLPs in comminuted olecranon fractures. Seven matched pairs of cadaveric upper extremities were evaluated with quantitative computed tomography scans to evaluate bone mineral density (BMD). Osteotomies simulating comminuted olecranon fractures (Mayo Type IIB) were created and the specimens were fixed either with variable angle PLPs or variable angle DLPs. The specimens were then cyclically loaded and loaded to failure. The ultimate strength, fracture displacement, and mechanism of failure were recorded and compared across groups. The correlation between BMD and ultimate strength was analyzed. The mean total BMD was 0.79 g/cm2 (SD, 0.14 g/cm2). No specimen failed during cyclic testing. Five of 7 PLP specimens and 5 of 7 DLP specimens failed by fracture through the proximal screws though in different planes (sagittal vs axial splits, respectively). The mean ultimate strengths of the PLP (1077 N [SD, 462 N]) and DLP (1241 N [SD, 506 N]) groups were similar. There was a linear relationship between ultimate strength and BMD (R2= 0.33). Dual locking plates display biomechanical properties that suggest that they can be used in the fixation of comminuted olecranon fractures. Catastrophic failure of the fixation constructs occurs around stress risers at the proximal screws rather than due to displacement at the fracture itself. Dual locking plate constructs can be considered for use in the fixation of comminuted olecranon fractures.

Focus on interlocking intramedullary nailing without fluoroscopy in resource-limited settings: strategies, outcomes, and outlook.

Closed static interlocking nailing with c-arm guidance is the standard procedure for the treatment of closed diaphyseal fractures. In low-income settings, it is still very difficult to carry out such procedures because of few or absent image intensifiers (c-arm) despite the necessity. Authors provide a review of the literature on interlocking intramedullary nailing without fluoroscopy in resource-limited settings, followed by strategies, outcomes, and outlook. A comprehensive search of the PubMed, Web of Science, Embase, and Cochrane Library databases was performed with the help of a biomedical information specialist. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. We identified 15 series of interlocking intramedullary nailing without fluoroscopy in resource-limited settings. All papers focused on the care for long bones (humerus, femur, tibia). All studies discussed the quality of the nailing operative procedure. The entry point was described in five series; the nail insertion in the proximal and distal medullary canal was good in all studies. The distal locking was missed between 0 and 27%. Intraoperative strategies depend on the type of bone affected, the opening of the fracture site, the fracture line, and the availability of a functional orthopaedic table. Three techniques to insert the nail in the proximal and distal fracture fragment with reduction of the fracture site are described. Insertion of distal screws is possible by using ancillary devices. Outcomes are comparable to those of the series using c-arm guidance. In low-income countries, it can been proposed as an alternative to the gold standard in resources constraints settings. In high-income setting this technique can help to reduce exposure of X-ray. There is a need to improve equipment in low-income countries hospitals to make trauma surgery with c-arm a gold standard with a minimal exposure to radiation.

Evaluation of tibial fracture management by using dynamic compression plating with two proximal and two distal cortical screws- a case report in dog

Tibio-fibular fractures are very common in dog and cat. Such fractures are usually corrected by either internal or external fixation method. Internal fixation like dynamic compression plating with a minimum of total six to ten cortical screws is usually used for the management tibial fracture in dog. The objective of the present case study is to evaluate the efficacy of dynamic compression plating with a minimum of two cortical screws in each proximal and distal fracture fragments. The clinical case was performed in a five month old indigenous intact female dog weighing 12 kg which was suffering from mid-shaft left comminuted tibia and fibular fracture. Lameness grade, functional limb outcome and fracture healing were observed for the final outcome of dog. At 30th post-operative day, lameness grade was improved, functional limb outcome was excellent and progressive secondary bone healing was noticed without any complications.

Primary Radial Nerve Exploration Determined by Ultrasound in Pediatric Supracondylar Humerus Fracture: A Report of Two Cases

We report two pediatric cases of radial nerve palsy caused by supracondylar fracture of the humerus requiring nerve exploration. The children had comparable conditions, palsy types (complete motor and partial sensory) and radiographic findings. The fracture in the first case was managed conservatively with closed reduction and percutaneous pinning but, while the patient eventually recovered from the partial sensory palsy, her motor palsy remained unchanged. In the second case, ultrasound assessment of the nerve prior to fixation indicated that surgical exploration was needed as it revealed tethering on the edge of the proximal fracture fragment. The nerve was released during an open reduction and the patient subsequently recovered from both sensory and motor palsies. Ultrasonography proved essential in the initial clinical assessment by determining how to proceed. We recommend primary nerve exploration when ultrasound findings show entrapment or tethering of the radial nerve.

Intraoperative torsion control using the cortical step sign and diameter difference in tibial mid-shaft fractures.

Intramedullar nailing of tibial mid-shaft fractures is a common surgical treatment. Fracture reduction, however, remains challenging and maltorsion is a common discrepancy which aggravates functional impairment of gait and stability. The use of radiographic tools such as the cortical step sign (CSS) and the diameter difference sign (DDS) could improve fracture reduction. Therefore, the validity of the CSS and DDS was analyzed to facilitate detection of maltorsion in tibial mid-shaft fractures. Tibial mid-shaft fractures were induced in human cadaveric tibiae according to the AO classification type A3. Torsional discrepancies from 0° to 30° in-/external direction were enforced after intramedullary nailing. Fluoroscopic-guided fracture reduction was assessed in two planes via analysis of the medical cortical thickness (MCT), lateral cortical thickness (LCT), tibial diameter (TD), anterior cortical thickness (ACT), posterior cortical thickness (PCT) and the transverse diameter (TD) of the proximal and distal fracture fragment. The TD, LCT and ACT have shown a highly significant correlation to predict tibial maltorsion. While a model combining ACT, LCT, PCT and TD lateral was most suitable model to identify tibial maltorsion, a torsional discrepancy of 15°was most reliably detected with use of the TD and ACT. The present study has shown, that maltorsion can be reliably assessed by the CSS and DDS during fluoroscopy. Thus, torsional discrepancies in tibial mid-shaft fractures can be most reliably assessed in the lateral plane by analysis of the LCT and TD.

Predicting Syndesmotic Injury in OTA/AO 44-B2.1 (Danis-Weber B) Fractures.

To establish if preoperative radiographs could predict the rate of syndesmotic injury. Level 1 trauma center. Retrospective cohort study. There were 548 OTA/AO 44-B2.1 fractures that were reviewed, and 287 patients were included in the study. Ankle radiographs were used to determine the zone of distal extent of the proximal fracture fragment. Syndesmotic injury was defined as positive intraoperative stress examination that required syndesmotic fixation. There were 191 zone 1 (ending below the plafond) injuries, 57 zone 2 (ending between the physeal scar and the plafond) injuries, and 39 zone 3 (ending above the physeal scar) injuries. Of these, 17% (33 patients) of zone 1, 42% (24) of zone 2, and 74% (29) of zone 3 fractures had syndesmotic injuries. The relative risk of syndesmotic injury of zone 1 compared with zone 2 was 2.4 (P < 0.001), zone 1 to zone 3 was 4.3 (P < 0.001), and zone 2 to zone 3 was 1.8 (P = 0.002). The interobserver and intraobserver reliability was excellent (κ = 0.86, 0.94). OTA/AO 44-B2.1 fractures have a varying rate of syndesmotic injury. Weber B fractures that end between the level of the plafond and the physeal scar (zone 2) are 2.4 times more likely to have a syndesmotic injury compared with those that end below the plafond (zone 1). This is magnified in those injuries ending above the scar (zone 3). This simple classification of OTA/AO 44-B2.1 fractures is predictive of syndesmotic injury and may aid in preoperative counseling and planning. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Clincal observation of non-absorbable suture cerclage combined with patella claw fixation for treatment of inferior patella fractures

To investigate the effectiveness of non-absorbable suture cerclage combined with patella claw fixation for the treatment of inferior patella fractures. Between September 2016 and January 2019, 22 patients with inferior patella fractures were treated. There were 12 males and 10 females, with a mean age of 49.1 years (range, 32-67 years). The causes of injury were traffic accident in 8 cases, falling in 12 cases, and other causes in 2 cases. The interval from injury to operation was 3-7 days (mean, 4.4 days). For the operation, 3 or 4 longitudinal tunnels were drilled backward from the surface of the proximal fracture fragment with Kirschner wires; under the guidance of lumbar puncture needles and steel wires, non-absorbable suture passed through the tunnels and encircled the inferior fracture fragment, then tighten to achieve a satisfactory reduction of the fracture; finally, the patella claw was used to strengthen the fixation. During the follow-up, complications were observed, maximum motion range of the knee joint was measured, X-ray examination was performed and fracture healing time was recorded. The knee function was evaluated according to Böstman scores. All the 22 patients were followed up 12-36 months (mean, 19.4 months). No infection, joint stiffness, bone nonunion, loss of reduction, or displacement of internal fixation occurred. All fractures were clinically healed, and the bone healing time was 2-3 months (mean, 2.6 months). At last follow-up, the maxium motion range of knee joint was 130°-135°, with an average of 132.6°. The Böstman score of the affected knee was 28-30 (mean, 29.2). All cases were graded as excellent results. Non-absorbable suture cerclage combined with patella claw fixation for inferior patella fractures has the advantages of simple operation, reliable fixation, and few complications, and the clinical results are satisfactory.

Predicting Syndesmotic Injury in Weber B Ankle Fractures

Category:Trauma; AnkleIntroduction/Purpose:Accurate pre-operative diagnosis of syndesmotic injuries can be difficult in the setting of AO 44-B1 fractures. Ankle fractures with syndesmotic injuries have worse reported outcomes. No study has investigated the relative fracture height in determining potential syndesmotic injury. The goal of this study was to establish if pre-operative radiographs could accurately predict syndesmotic injury.Methods:Patients treated for an isolated AO 44-B1 fracture over a ten-year period (2007-2017) were reviewed. Anteroposterior and mortise views of the ankle were used to determine the zone of distal extent of the proximal fracture fragment (Figure 1). Syndesmotic injury was defined as positive intraoperative stress exam that required syndesmotic fixation. Relative risks were determined between zones with a statistical significance set at 0.05. Ten randomly selected radiographs were reviewed by two authors and assessed by intra-class correlation (ICC) for inter- and intra-observer reliability.Results:There were 548 AO 44-B1 fractures that were reviewed; and 287 patients were included in the study. There were 191 zone 1 injuries, 57 zone 2 injuries, and 39 zone 3 injuries. Of these, 17% (33 patients) of zone 1, 42% (24) of zone 2, and 74% (29) of zone 3 fractures had syndesmotic injuries. The relative risk of syndesmotic injury of Zone 1 compared to Zone 2 was 2.4 (p<0.001), Zone 1 to Zone 3 was 4.3 (p<0.001), Zone 2 to Zone 3 was 1.8 (p=0.002). The ICC for inter- and intra-observer reliability was perfect (ICC=1).Conclusion:AO 44-B1 fractures have a varying rate of syndesmotic injury. Weber B fractures that end between the level of the plafond and the physeal scar (Zone 2) are 2.6 times more likely to have a syndesmotic injury compared to those that end below the plafond (Zone 1). This is magnified in those injuries ending above the scar (Zone 3). This simple classification of AO 44-B1 fractures is predictive of syndesmotic injury and may aid in preoperative counseling and planning.

Radiostereometric Analysis of Stability and Inducible Micromotion After Locked Lateral Plating of Distal Femur Fractures.

To evaluate interfragmentary motion over 1 year after distal femoral fracture fixation using radiostereometric analysis (RSA). The secondary aim was to assess whether RSA data are consistent with diagnoses of nonunion. Prospective cohort study. Level I urban trauma center. Sixteen patients between 22 and 89 years of age with distal femoral fracture (OTA/AO type 33). All fractures were treated with a lateral locking plate, and tantalum markers were inserted into the main proximal and distal fracture fragments. RSA was performed at 2, 6, 12, 18, and 52 weeks postoperatively. Both unloaded and loaded RSA measurements were performed. Unloaded fracture migration over time and inducible micromotion at the fracture site in the coronal plane were determined at each follow-up interval. RSA precision in the coronal plane of interfragmentary motion over time and inducible micromotion were 1.2 and 0.9 mm in the coronal plane, respectively. Two cases required revision surgery for nonunion 1 year postoperatively. For cases of union, unloaded fracture migration stopped being detectable between 12 and 18 weeks, and inducible micromotion was no longer detectable by the 12-week visit. For cases of nonunion, both unloaded migration and inducible micromotion were detected throughout the study period. RSA may be used to reliably assess distal femoral fracture healing. RSA revealed differences in cases of union and nonunion by 3 months and more consistently than traditional x-rays. Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.