Induced Membrane Technique Is Effective for the Management of Acute Traumatic Bone Loss in Both Diaphyseal and Metaphyseal Lower Extremity Fractures.

OBJECTIVE: To compare outcomes of Masquelet-induced membrane technique (IMT) in metaphyseal and diaphyseal fractures with acute bone loss. DESIGN: Retrospective cohort study. SETTING: Four Level 1 Academic Trauma Centers. PATIENTS/PARTICIPANTS: Patients acutely treated with IMT for traumatic lower extremity bone loss at 4 Level 1 trauma centers between 2010 and 2020. INTERVENTION: Operative treatment with placement of cement spacer within 3 weeks of initial injury followed by staged removal and bone grafting to the defect. MAIN OUTCOME MEASUREMENTS: Fracture union, infection, revision grafting, time to union, and amputation. RESULTS: One hundred twenty fractures met inclusion criteria, including 43 diaphyseal fractures (DIM) and 77 metaphyseal fractures (MIM). Demographic characteristics were not significantly different, except for age (DIM 34 years vs. MIM 43 years, P < 0.001). Union after treatment with IMT was 89.2% overall. After controlling for age, this was not significantly different between DIM (41/43, 95.3%) and MIM (66/77, 85.7%) ( P = 0.13) nor was the rate of infection between groups. There was no difference in any secondary outcomes. CONCLUSIONS: The overall union rate in the current series of acute lower extremity fractures treated with the induced membrane technique was 89%. There was no difference in successful union between patients with diaphyseal bone loss or metaphyseal bone loss treated with IMT. Similarly, there was no difference in patients with tibial or femoral bone loss treated with induced membrane. Defect size after debridement may be more prognostic for secondary operations rather than the limb segment involved or the degree of soft-tissue injury. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Risk Factors for Nonunion of Distal Femur Fractures.

OBJECTIVES: To determine patient, fracture, and construct related risk factors associated with nonunion of distal femur fractures. DESIGN: Retrospective cohort study. SETTING: Academic Level I trauma center. PARTICIPANTS: Patients 18 years and older presenting with OTA/AO 33A and 33C distal femur fractures from 2004 to 2020. A minimum follow-up of 6 months was required for inclusion. OTA/AO 33B and periprosthetic fractures were excluded, 438 patients met inclusion criteria for the study. MAIN OUTCOMES: The primary outcome of the study was fracture nonunion defined as a return to the OR for management of inadequate bony healing. Patient demographics, comorbidities, injury characteristics, fixation type, and construct variables were assessed for association with distal femur fracture nonunion. Secondary outcomes include conversion to total knee arthroplasty, surgical site infection, and other reoperation. RESULTS: The overall nonunion rate was 13.8% (61/438). The nonunion group was compared directly with the fracture union group for statistical analysis. There were no differences in age, sex, mechanism of injury, Injury Severity Score, and time to surgery between the groups. Lateral locked plating characteristics including length of plate, plate metallurgy, screw density, and working length were not significantly different between groups. Increased body mass index [odds ratio (OR), 1.05], chronic anemia (OR, 5.4), open fracture (OR, 3.74), and segmental bone loss (OR, 2.99) were independently associated with nonunion. Conversion to total knee arthroplasty (TKA) ( P = 0.005) and surgical site infection ( P < 0001) were significantly more common in the nonunion group. CONCLUSION: Segmental bone loss, open fractures, chronic anemia, and increasing body mass index are significant risk factors in the occurrence of distal femoral nonunion. Lateral locked plating characteristics did not seem to affect nonunion rates. Further investigation into the prevention of nonunion should focus on fracture fixation constructs and infection prevention. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.