Predictive factors of distal femoral fracture nonunion after lateral locked plating: a retrospective multicenter case-control study of 283 fractures

Comparison of 4 Methods for Dynamization of Locking Plates: Differences in the Amount and Type of Fracture Motion

BACKGROUND

Decreasing the stiffness of locked plating constructs can promote natural fracture healing by controlled dynamization of the fracture. This biomechanical study compared the effect of 4 different stiffness reduction methods on interfragmentary motion by measuring axial motion and shear motion at the fracture site.

METHODS

Distal femur locking plates were applied to bridge a metadiaphyseal fracture in femur surrogates. A locked construct with a short-bridge span served as the nondynamized control group (LOCKED). Four different methods for stiffness reduction were evaluated: replacing diaphyseal locking screws with nonlocked screws (NONLOCKED); bridge dynamization (BRIDGE) with 2 empty screw holes proximal to the fracture; screw dynamization with far cortical locking (FCL) screws; and plate dynamization with active locking plates (ACTIVE). Construct stiffness, axial motion, and shear motion at the fracture site were measured to characterize each dynamization methods.

RESULTS

Compared with LOCKED control constructs, NONLOCKED constructs had a similar stiffness (P = 0.08), axial motion (P = 0.07), and shear motion (P = 0.97). BRIDGE constructs reduced stiffness by 45% compared with LOCKED constructs (P < 0.001), but interfragmentary motion was dominated by shear. Compared with LOCKED constructs, FCL and ACTIVE constructs reduced stiffness by 62% (P < 0.001) and 75% (P < 0.001), respectively, and significantly increased axial motion, but not shear motion.

CONCLUSIONS

In a surrogate model of a distal femur fracture, replacing locked with nonlocked diaphyseal screws does not significantly decrease construct stiffness and does not enhance interfragmentary motion. A longer bridge span primarily increases shear motion, not axial motion. The use of FCL screws or active plating delivers axial dynamization without introducing shear motion.

Outcomes of Distal Femur Nonunions Treated With a Combined Nail/Plate Construct and Autogenous Bone Grafting

In this study, we sought to retrospectively evaluate union and infection rates after treatment of distal femur nonunions using a combined nail/plate construct with autogenous bone grafting obtained from the ipsilateral femur using a reamer irrigator aspirator system. Ten (10) patients treated at a Level I trauma center for nonunion of a femoral fracture using a combined nail/plate construct from 2004 to 2014 were included in the study. Union rate and postoperative infection rates were recorded. Mean interval from index surgery to nonunion repair was 12 months (range 4-36 months). Follow-up at 24 months indicated that the entire cohort of 10 patients achieved clinical union and radiographic union based on radiograph union score in tibias (RUST) criteria. Treatment of distal femur nonunions with a combined nail/plate construct and autogenous bone grafting results in a high rate of union with a low complication rate.

Implant Material, Type of Fixation at the Shaft, and Position of Plate Modify Biomechanics of Distal Femur Plate Osteosynthesis

OBJECTIVES

To investigate whether (1) the type of fixation at the shaft (hybrid vs. locking), (2) the position of the plate (offset vs. contact) and (3) the implant material has a significant effect on (a) construct stiffness and (b) fatigue life in a distal femur extraarticular comminuted fracture model using the same design of distal femur periarticular locking plate.

METHODS

An extraarticular severely comminuted distal femoral fracture pattern (OTA/AO 33-A3) was simulated using artificial bone substitutes. Ten-hole distal lateral femur locking plates were used for fixation per the recommended surgical technique. At the distal metaphyseal fragment, all possible locking screws were placed. For the proximal diaphyseal fragment, different types of screws were used to create 4 different fixation constructs: (1) stainless steel hybrid (SSH), (2) stainless steel locked (SSL), (3) titanium locked (TiL), and (4) stainless steel locked with 5-mm offset at the diaphysis (SSLO). Six specimens of each construct configuration were tested. First, each specimen was nondestructively loaded axially to determine the stiffness. Then, each specimen was cyclically loaded with increasing load levels until failure.

RESULTS

Construct Stiffness: The fixation construct with a stainless steel plate and hybrid fixation (SSH) had the highest stiffness followed by the construct with a stainless steel plate and locking screws (SSL) and were not statistically different from each other. Offset placement (SSLO) and using a titanium implant (TiL) significantly reduced construct stiffness. Fatigue Failure: The stainless steel with hybrid fixation group (SSH) withstood the most number of cycles to failure and higher loads, followed by the stainless steel plate and locking screw group (SSL), stainless steel plate with locking screws and offset group (SSLO), and the titanium plate and locking screws group (TiL) consecutively. Offset placement (SSLO) as well as using a titanium implant (TiL) reduced cycles to failure.

CONCLUSIONS

Using the same plate design, the study showed that implant material, screw type, and position of the plate affect the construct stiffness and fatigue life of the fixation construct. With this knowledge, the surgeon can decide the optimal construct based on a given fracture pattern, bone strength, and reduction quality.

Treatment of Distal Femur Nonunion Following Initial Fixation with a Lateral Locking Plate

OBJECTIVE

To report and evaluate the outcomes of patients undergoing definitive treatment for distal femur nonunion after initial treatment with a locking plate.

METHODS

Fourteen patients who had undergone definitive treatment at an academic Level 1 trauma center from May 2007 to December 2013 for distal femur nonunion were identified from a fracture database. Thirteen of them were female; the average age was 65 years (range, 50-84 years). Ten patients had sustained their injuries in falls at ground level, and four in motor vehicle accidents. Twelve patients were obese (body mass index ≥30), 10 had diabetes, none were current smokers, and one had an open fracture classified as type IIIa according to the Gustilo-Anderson classification system for open fractures. The fractures were classified according to the AO classification system for distal femur fractures; there were three type 33-A1, six 33-A2, two 33-A3 and three 33-C3 fractures. Methods of definitive treatment involved open reduction and internal fixation (ORIF) revision, medial plating, bone grafting and the use of other biologic materials.

RESULTS

Eight of the 14 patients (57%) achieved union during follow-up. Definitive treatment for nonunion involved ORIF revision in 11 cases. Three patients who did not undergo ORIF revision were treated with iliac crest stem cell autografts, bone graft substitutes or recombinant human-bone morphogenetic protein-2 (rh-BMP-2). Other treatments included rh-BMP-2 (12 cases), iliac crest bone autograft (five), iliac crest stem cell autograft (two), crushed cancellous bone allograft (three), CaSO 4 and tricalcium phosphate bone graft substitute (two) and demineralized bone matrix (one). The average time from definitive treatment to union was 19 weeks (range, 12-51 weeks). Two of the 11 cases who underwent ORIF revision had medial plates added to improve biomechanical stability and prevent varus collapse. This was also performed in one patient with a grade III open type 33-C3 fracture and one with a closed 33-A2 fracture. Five study patients had comminuted fractures. Two had type 33-A3 and three type 33-C3 fractures. Both patients with 33-A3 fractures and 2 two with 33-C3 fractures had persistent nonunion at the end of follow-up.

CONCLUSIONS

Definitive treatment of distal femur nonunion after initial treatment with a locking plate had a low rate of success in this study, suggesting that this procedure is ineffective as a definitive treatment for distal femur nonunion.

Minimally invasive internal fixation of distal femur fractures

Fractures of the distal femur remain a daunting challenge. Since 1970, operative treatment has been recommended. Unfortunately, it is fraught with complications, and techniques have been developed to limit incidence of non-union, infection and stiffness. A soft-tissue friendly approach is the key point, with minimally invasive surgery as the ultimate goal: its biological and anatomical advantages have been demonstrated, but clinical studies have been less convincing, being based on historical series. At present, retrograde nailing and minimally invasive percutaneous plate osteosynthesis (ideally by locking plate) are the two main techniques. Unfortunately, reports tend to compare implants rather than operative techniques, hindering solid conclusions. Lastly, the delineation of "distal femur fracture" is quite variable, sometimes situated well above the AO epiphyseal square. Meta-analyses find almost no difference between the two implants in minimally invasive procedures. The main advantage of the plate is its versatility, whereas nailing can be impossible in case of certain hip or knee prostheses, compound articular fracture or medullary canal obstruction by fixation material (nail, stem, screw, etc.). The role of arthroscopy is limited. Only a few case reports describe its use in reduction of epiphyseal fracture. In the last analysis, the surgeon's experience is more relevant to outcome than any particular implant.

Open Reduction vs Distal Femoral Replacement Arthroplasty for Comminuted Distal Femur Fractures in the Patients 70 Years and Older

BACKGROUND

The ideal management of distal femur fractures in the elderly is unclear. Acute arthroplasty has the theoretical advantage of earlier mobilization. We examined the outcomes of patients 70 years and older who underwent open reduction internal fixation (ORIF) vs distal femoral replacement (DFR) for comminuted, intra-articular distal femur fractures.

METHODS

A retrospective review of patients with AO/OTA classification 33C distal femur fractures treated with either ORIF or DFR was performed. Outcomes including all-cause reoperation, length of stay, fracture union, postoperative complications, use of ambulatory device and living situation at 1 year, and mortality were evaluated.

RESULTS

The study cohort included 38 patients: 10 underwent DFR and 28 ORIF. Mean patient age for both cohorts was 82 years. No difference in comorbidities or mechanism of injury was found between groups. The incidence of reoperation was 11% in the ORIF group and 10% in the DFR group. In the ORIF group, the average time to fracture union was 24 weeks, with a nonunion incidence of 18%. Twenty-three percent of ORIF group were wheelchair dependent vs none in the DFR cohort, although not statistically significant. Differences between the groups with respect to all-cause reoperation, living situation or need for ambulatory device at 1 year, and 1-year mortality did not reach statistical significance.

CONCLUSION

Nearly 1 in 5 patients older than 70 years developed a nonunion after ORIF of an intra-articular distal femur fracture. At 1-year follow-up, all patients in DFR group were ambulatory while 1 in 4 in the ORIF group were wheelchair bound.

Early prediction of tibial and femoral fracture healing: Are we reliable?

INTRODUCTION

To evaluate the ability of orthopaedic trauma subspecialists to predict early bony union in femoral and tibia shaft fractures.

MATERIALS AND METHODS

Eight orthopaedic trauma subspecialists prospectively predicted the probability of bony union at 6 and 12 weeks post-operatively for an aggregate of 48 femoral and tibial shaft fractures treated at a Level 1 trauma centre. An additional orthopaedic trauma subspecialist was blinded to treating surgeon and adjudicated healing at 18 weeks. The Squared-Error Skill Score (SESS) determined the likelihood of accurate forecasting for bony union.

RESULTS

Nine patients were lost follow-up, resulting in 39 fractures (81.25% retention) including 20 femoral and 19 tibial fractures. Fourteen fractures were open, 15 were not-yet united at final follow-up. SESS values were 0.25-0.77. The ability to predict union (sensitivity) was 1.000. The ability to predict nonunions (specificity) was 0.330-0.500. The probability of a correct predicted union was 0.727 and correct predicted nonunion at final follow-up was 1.000. AO/OTA type A fractures pattern predictions were highly accurate. As body mass index increased, predictions trended toward decreased accuracy (p=0.06). Tobacco use, age, gender, associated injuries, open fractures, and surgeons' years in clinical practice were not associated with accuracy of predictions.

CONCLUSIONS

At 12-weeks post-operatively orthopaedic trauma subspecialists can confidently predict the union state in this patient population. This data is most useful in the nonunion patient, directing early intervention, thereby decreasing patient disability and discomfort.

Stress Modulation of Fracture Fixation Implants

Stress modulation is the concept of manipulating bridge plate variables to provide a flexible fixation construct that allows callus formation through uneventful secondary bone healing. Obtaining absolute stability through the anatomic reduction of all fracture fragments comes at the expense of fracture biology, whereas intramedullary nailing, which is more advantageous for diaphyseal fractures of the lower extremity, is technically demanding and often may not be possible when stabilizing many metaphyseal fractures. Overly stiff plating constructs are associated with asymmetric callus formation, early implant failure, and fracture nonunion. Numerous surgeon-controlled variables can be manipulated to increase flexibility without sacrificing strength, including using longer plates with well-spaced screws, choosing titanium or stainless steel implants, and using locking or nonlocking screws. Axially dynamic emerging concepts, such as far cortical locking and near cortical overdrilling, provide further treatment options when bridge plating techniques are used.

Mechanical Construct Characteristics Predisposing to Non-union After Locked Lateral Plating of Distal Femur Fractures

OBJECTIVES

To identify discrete construct characteristics related to overall construct rigidity that may be independent predictors of nonunion after lateral locked plate (LLP) fixation of distal femur fractures.

DESIGN

Retrospective case-control study.

SETTING

Three level-1 urban trauma centers.

PATIENTS/PARTICIPANTS

Two hundred and seventy-one supracondylar femoral fractures treated with LLP at 3 affiliated level 1 urban trauma centers between August 2004 and December 2010.

METHODS

Nonunion was defined as a secondary procedure for poor healing. Construct variables included: (1) combined plate design and material variable, (2) Plate length, (3) # screws proximal to fracture, (4) total screw density (TSD), (5) proximal screw density (PSD), (6) presence of a screw crossing the main fracture, and (7) rigidity score multivariable analysis was performed using logistic regression to identify independent risk factors for nonunion.

INTERVENTION

LLP fixation.

MAIN OUTCOME MEASURE

Nonunion.

RESULTS

Nonunion rate was 13.3% (n = 36). There was a significant association between plate design/material and nonunion with 41% of stainless constructs and 10% of titanium constructs resulting in a nonunion (P < 0.001). Rigidity scores reached significance (P = 0.001) with constructs resulting in a nonunion having higher scores. No significant univariate differences with respect to number of proximal screws, plate length, total screw density, or proximal screw density were observed between healed fractures and those with nonunion. Results of the multivariate analysis confirmed that the primary significant independent predictor of nonunion was plate design/material (odds ratio, 6.8; 95% CI, 2.9-16.1; P < 0.001).

CONCLUSIONS

When treating distal femur fractures with LLP, combined plate design and material variable has a highly significant influence on the risk of nonunion independent of any other construct variable.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Treatment Options for Distal Femur Fractures

Despite advances in implant design, the management of distal femur fractures remains challenging. Fracture comminution and intra-articular extension can make it difficult to obtain an adequate reduction while preserving the soft tissue attachments to bone fragments to allow for bone healing. Many implant manufacturers have developed optimal anatomically contoured, distal femoral locking plates with percutaneous guides. This environment allows for the application of lateral locked plates in a biologically friendly manner. Although initial reports had high success rates, more recently a high rate of nonunion has been found, particularly in elderly patients. Limited literature is available for the treatment of patients with osteoporotic bone and associated ipsilateral total knee replacement and hip replacement. We present a patient with a distal femur fracture with significant comminution in the setting of an ipsilateral total hip replacement.

Geriatric distal femur fracture: Are we underestimating the rate of local and systemic complications?

BACKGROUND

Low energy distal femur fractures often occur in a fragile elderly population that is prone to local and systemic complications following operative treatment of extremity fractures. The nonunion rate and early complication rate following laterally based locked plating in this specific fracture are not well described.

METHODS

We conducted a retrospective cohort study conducted at three affiliated tertiary care hospitals to evaluate nonunion, early post operative complications, discharge disposition, length of stay, and mortality in patients over 60 years old undergoing laterally based locked plating of a low energy distal femur fracture.

RESULTS

Forty-four out of 176 patients were deceased at one year (25%). Predictors of one year mortality included older age, higher Charlson Comorbidity Index (CCI), and delay to surgery greater than 2days (p<0.001). Of 99 patients alive and with follow up at one year, 24 (24%) developed a nonunion and 21 of 24 required nonunion surgery. Development of a surgical site infection was statistically significantly correlated with development of nonunion. Age and CCI did not predict development of nonunion. Average length of stay was 10days and 82% of patients were discharged to a skilled nursing facility. Thirty eight percent of patients experienced at least one postoperative systemic complication.

CONCLUSIONS

Laterally based locked plating of the low energy geriatric distal femur fracture is most often followed by a tumultuous post-operative course with a high rate of local and systemic complications including death, nonunion, and extended hospital stays.

LEVEL OF EVIDENCE

Level III prognostic.

LCP Versus LISS in the Treatment of Open and Closed Distal Femur Fractures: Does it Make a Difference?

OBJECTIVES

We compared the postoperative complication rates between the less invasive stabilization system (LISS) plating and locking compression plate for open and closed distal femoral fracture fixation for superiority.

DESIGN

Retrospective Review.

SETTING

Multicenter.

PARTICIPANTS

Patients identified through a hospital database who were treated for supracondylar femur fractures using LISS or LCP techniques between January 2005 and July 2010.

INTERVENTION

Medical history, patient demographics, injury characteristics, presence of polytrauma, and surgical characteristics were collected for each patient.

MAIN OUTCOME MEASUREMENTS

χ and logistic regression analysis was performed to compare postoperative infection and nonunion/reoperation regarding both plating techniques.

RESULTS

Of 339 distal femoral fractures, 185 (54.6%) were repaired with a LISS plate and 154 (45.4%) were repaired with a LCP. Multivariate analysis revealed only open fractures to be a risk factor for nonunion (Odds ratio 2.42, P = 0.01) and infection (Odds ratio 3.47, P = 0.02), regardless of device used. No difference was seen between either plate type in infection, plate failure, or nonunion.

CONCLUSIONS

Postoperative infection and nonunion rates are comparable between LISS and LCP for both open and closed distal femoral fracture fixation. As no difference was detected between plates, either may be used to treat distal femur fractures. Nonunion rate was higher than expected based on previous reports.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Nonunion of the Femur and Tibia: An Update

Delayed union and nonunion of tibial and femoral shaft fractures are common orthopedic problems. Numerous publications address lower extremity long bone nonunions. This review presents current trends and recent literature on the evaluation and treatment of nonunions of the tibia and femur. New studies focused on tibial nonunion and femoral nonunion are reviewed. A section summarizing recent treatment of atypical femoral fractures associated with bisphosphonate therapy is also included.

Obesity is associated with increased postoperative complications after operative management of tibial shaft fractures

OBJECTIVES

To assess the association of obesity and postoperative complications after operative management of tibial shaft fractures.

METHODS

Patients who underwent operative management of a tibial shaft fracture were identified in a national database by Current Procedural Terminology (CPT) codes for: (1) open reduction and internal fixation (ORIF) and (2) intramedullary nailing (IMN) procedures in the setting of International Classification of Diseases, Ninth Revision (ICD-9) codes for tibial shaft fracture. These groups were then divided into non-obese, obese, and morbidly obese cohorts using ICD-9 codes. Each cohort was then assessed for grouped complications within 90 days, removal of implants within 6 months, and nonunion within 9 months postoperatively. Odds ratios and 95% confidence intervals were calculated.

RESULTS

From 2005 to 2012, 14,638 patients who underwent operative management of tibial shaft fractures were identified, including 4425 (30.2%) ORIF and 10,213 (69.8%) IMN. Overall, 1091 patients (7.4%) were coded as obese and 820 (5.6%) morbidly obese. In each operative group, obesity and morbid obesity was associated with a substantial increase in the rate of major and minor medical complications, venous thromboembolism, infection, procedures for implant removal, and nonunion.

CONCLUSIONS

In patients who undergo either ORIF or IMN for tibial shaft fractures, obesity and its related medical comorbidities are associated with significantly increased rates of postoperative medical complications, infection, nonunion, and implant removal compared to non-obese patients.

Comparison of Short-Term Outcomes of Geriatric Distal Femur and Femoral Neck Fractures: Results From the NSQIP Database

Purpose:

To compare and contrast postoperative complications in the geriatric population following open reduction and internal fixation (ORIF) for (DF) fractures relative to femoral neck (FN) fractures.

Methods:

Patients aged 65 years and older in the American College of Surgeons National Surgical Quality Improvement Program database who underwent ORIF for FN fractures or DF fractures from 2005 to 2012 were identified. Differences in rates of any adverse events (AAEs), serious adverse events (SAEs), infectious complications, and mortality between groups were explored using univariate and multivariate analyses.

Results:

The DF cohort had a higher proportion of females (81.95% vs 71.35%, P < .001), were younger (79.41 ± 7.93 vs 82.11 ± 7.26 years old, P < .001), and had a lower age adjusted modified Charlson comorbidity index score (4.22 ± 1.32 vs 4.49 ± 1.35, P = .02). Cases with DF and FN did not differ in AAE (20.05% vs 20.20%, P = .94), SAE (12.03% vs 13.19%, P = .51), infectious complication (4.26% vs 4.22%, P = .97), hospital length of stay (7.32 ± 6.73 days vs 7.02 ± 10.67 days, P = .59), or mortality rates (4.51% vs 5.99%, P = .23). Multivariate analyses revealed that fracture type did not impact AAE (P = .28), SAE (P = .58), infectious complications (P = .83), or mortality (P = .85) rates.

Conclusion:

Postoperative morbidity and mortality of geriatric patients who sustain DF and FN fractures treated operatively were comparable. This information can be used when risk stratifying and prognosticating for elderly patients undergoing these procedures.

Risk factors for long bone fracture non-union: a stratification approach based on the level of the existing scientific evidence

Non-union continues to be the most devastating complication after fracture fixation. Its treatment can be prolonged and often unpredictable. The burden to the patient, surgeon and health care system can be immense. Strategies to prevent it and or identify early its development are desirable in order to improve the clinical course of the affected patients and their outcomes. We undertook a systematic review of the literature in order to identify the most common and important risk factors based on the hierarchy of level of evidence. Accordingly, a stratification scale was formed which highlighted 10 risk factors including; an open method of fracture reduction, open fracture, presence of post-surgical fracture gap, smoking, infection, wedge or comminuted types of fracture, high degree of initial fracture displacement, lack of adequate mechanical stability provided by the implant used, fracture location in the poor zone of vascularity of the affected bone, and the presence of the fracture in the tibia. Clinicians should take in to account these findings when managing patients with long bone fractures, particularly the femur and tibia in order to minimise the risk of non-union.

Biomechanical Concepts for Fracture Fixation

Application of the correct fixation construct is critical for fracture healing and long-term stability; however, it is a complex issue with numerous significant factors. This review describes a number of common fracture types and evaluates their currently available fracture fixation constructs. In the setting of complex elbow instability, stable fixation or radial head replacement with an appropriately sized implant in conjunction with ligamentous repair is required to restore stability. For unstable sacral fractures with vertical or multiplanar instabilities, "standard" iliosacral screw fixation is not sufficient. Periprosthetic femur fractures, in particular Vancouver B1 fractures, have increased stability when using 90/90 fixation versus a single locking plate. Far cortical locking combines the concept of dynamization with locked plating to achieve superior healing of a distal femur fracture. Finally, there is no ideal construct for syndesmotic fracture stabilization; however, these fractures should be fixed using a device that allows for sufficient motion in the syndesmosis. In general, orthopaedic surgeons should select a fracture fixation construct that restores stability and promotes healing at the fracture site, while reducing the potential for fixation failure.

Perioperative adverse events in distal femur fractures treated with intramedullary nail versus plate and screw fixation

BACKGROUND

To compare 30-day outcomes in patients treated for a distal femur (DF) fracture with plate fixation (PF) or intramedullary nail (IMN).

METHODS

Differences in rates of any adverse events (AAE), serious adverse events (SAE), infectious complications, and mortality were explored between groups in the ACS-NSQIP database.

RESULTS

There were 511 PF and 44 IMN patients. The PF group and IMN groups had similar rates of AAEs (p = 0.35), SAEs (p = 0.46), infectious complications (p = 1.00), and mortality (p = 0.39).

CONCLUSIONS

DF fractures treated with IMN have equivalent short-term outcomes compared to those treated with PF.

The outcome of Polyax Locked Plating System for fixation distal femoral non-implant related and periprosthetic fractures

The objective of this study was to report on the safety, efficacy and clinical outcomes of the Polyax Locked Plating System (Biomet, Warsaw, IN, USA) in the management of acute (non-implant related and periprosthetic) distal femoral fractures. We retrospectively reviewed 71 patients with 73 distal femoral fractures. Thirty-three of the included fractures occurred around previously placed implants. The average patients' age was 67 years (range 18-98). There were 7 early postoperative complications (9.5%) including one deep surgical site infection, 2 pulmonary embolisms and 4 urinary or respiratory infections. At final follow-up (mean 12, range 9-55 months) all fractures progressed to clinical and radiological union. However, major revision surgery for healing problems was required in 5 cases (6.8%) and minor in 3 cases (4.1%). The average time to healing was 6 (range 3-23) months. Angulation less than 5 degrees in any plane was observed in 66 cases (89.7%), within 5-10 degrees in 5 cases (7.3%) and within 10-15 degrees in 2 cases (2.9%). The mean pre-injury and final follow-up values of Glasgow Outcome Scale were 1.5(1-3) and 1.7(1-3) respectively. Overall 61 patients (83.53%) retained their pre-injury activity status. The Polyax Locked Plating System offers a safe and efficient fixation in distal femoral fractures.

Dynamic Locked Plating of Distal Femur Fractures

OBJECTIVES

Nonunion after locked bridge plating of comminuted distal femur fractures is not uncommon. "Dynamic" locked plating may create an improved mechanical environment, thereby achieving higher union rates than standard locked plating constructs.

SETTING

Academic Level 1 Trauma Center.

PATIENTS/PARTICIPANTS

Twenty-eight patients with comminuted supracondylar femur fractures treated with either dynamic or standard locked plating.

INTERVENTION

Dynamic plating was achieved using an overdrilling technique of the near cortex to allow for a 0.5-mm "halo" around the screw shaft at the near cortex. Standard locked plating was done based on manufacturer's suggested technique. The patients treated with dynamic plating were matched 1:1 with those treated with standard locked plating based on OTA classification and working length.

MAIN OUTCOME MEASUREMENTS

Three blinded observers made callus measurements on 6-week radiographs using a 4-point ordinal scale. The results were analyzed using a 2-tailed t test and 2-way intraclass correlations.

RESULTS

The dynamic plating group had significantly greater callus (2.0; SD, 0.7) compared with the control group (1.3: SD, 0.8, P = 0.048) with substantial agreement amongst observers in both consistency (0.724) and absolute score (0.734). With dynamic plating group, 1 patient failed to unite, versus three in the control group (P = 0.59). The dynamic group had a mean change in coronal plane alignment of 0.5 degrees (SD, 2.6) compared with 0.6 (SD, 3.0) for the control group (P = 0.9) without fixation failure in either group.

CONCLUSIONS

Overdrilling the near cortex in metaphyseal bridge plating can be adapted to standard implants to create a dynamic construct and increase axial motion. This technique seems to be safe and leads to increased callus formation, which may decrease nonunion rates seen with standard locked plating.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Fibrinolysis is essential for fracture repair and prevention of heterotopic ossification

Bone formation during fracture repair inevitably initiates within or around extravascular deposits of a fibrin-rich matrix. In addition to a central role in hemostasis, fibrin is thought to enhance bone repair by supporting inflammatory and mesenchymal progenitor egress into the zone of injury. However, given that a failure of efficient fibrin clearance can impede normal wound repair, the precise contribution of fibrin to bone fracture repair, whether supportive or detrimental, is unknown. Here, we employed mice with genetically and pharmacologically imposed deficits in the fibrin precursor fibrinogen and fibrin-degrading plasminogen to explore the hypothesis that fibrin is vital to the initiation of fracture repair, but impaired fibrin clearance results in derangements in bone fracture repair. In contrast to our hypothesis, fibrin was entirely dispensable for long-bone fracture repair, as healing fractures in fibrinogen-deficient mice were indistinguishable from those in control animals. However, failure to clear fibrin from the fracture site in plasminogen-deficient mice severely impaired fracture vascularization, precluded bone union, and resulted in robust heterotopic ossification. Pharmacological fibrinogen depletion in plasminogen-deficient animals restored a normal pattern of fracture repair and substantially limited heterotopic ossification. Fibrin is therefore not essential for fracture repair, but inefficient fibrinolysis decreases endochondral angiogenesis and ossification, thereby inhibiting fracture repair.

Internal fixation of osteoporotic fractures

Osteoporosis leads to bone fragility and increased risk of fracture. Despite advances in diagnosis and treatment, the prevalence continues to rise. Osteoporotic fracture treatment has a unique set of difficulties related to poor bone quality and traditional approaches, and implants may not perform well. Fixation failure and repeat surgery are poorly tolerated and highly undesirable in this patient population. This review illustrates the most recent updates in internal fixation, implant design, and surgical theory regarding treatment of patients with osteoporotic fractures.