Predictors of Early Failure of Fixation in the Treatment of Displaced Subcapital Hip Fractures

Abstract
To examine predictors of fixation failure in the treatment of displaced subcapital hip fractures. Retrospective study. All patients aged sixty-five years and older discharged from a large teaching hospital after treatment for displaced subcapital fracture between April 1, 1989 and February 29, 1995 were identified (n = 344). Of these, 108 patients treated with internal fixation became the study group. Clinical information included demographics, implant, comorbidity, complications, mortality, surgeon's assessment of reduction, and need for revision. Preoperative x-ray information: Garden grade, Singh Index, Pauwel's angle, medial neck and femoral shaft cortex width, and displacement of fracture fragments. Postoperative: Quality of reduction, a visible gap or step, evidence of union, fracture collapse, and failure. The failure rate was 31 percent. The two most important predictors were varus reduction and perceived difficulty in achieving reduction. If the patient had a varus reduction or the surgeon had difficulty achieving a satisfactory reduction, fixation was 4.3 times more likely to fail (p = 0.007). If the patient had a varus reduction and reduction was difficult, fixation was 13.6 times more likely to fail (p = 0.04). Under this latter scenario, 75 percent of the fixations failed. In a fracture of the neck of the femur, if difficulty is encountered in obtaining a closed reduction or there is residual varus angulation, the chance of subsequent fixation failure is high. Hemiarthroplasty may be considered in these cases.