Session IX - Femur
Sat, 10/9/04 Femur, Paper #55, 4:47 pm
Functional Outcome and Time Course of Recovery after Femur Fracture: Does Knee Pain Matter?
Purpose: Previous studies have demonstrated that recovery after femur fractures can be slow. A high incidence of hip and knee pain has been reported. This study was performed to assess the time course of functional recovery and to compare pain at the knee, thigh, buttock, and groin with functional outcome scores 6 months after isolated femur fractures.
Methods: Forty skeletally mature patients with isolated diaphyseal femoral fractures (OTA 42 A, B and C) treated with locked antegrade intramedullary nails were prospectively enrolled. Exclusion criteria included polytrauma, ipsilateral injuries, metaphyseal extension, and pathologic fractures. All femoral nails were inserted by using a percutaneous technique. Open reduction was performed in two patients.
Functional outcomes were assessed with use of the Western Ontario-McMaster University Osteoarthritis Index (WOMAC) and the Short Musculoskeletal Function Assessment (SMFA). At the 6-month follow-up appointment, all patients were examined by a physician for range of motion and evidence of joint instability. Standing 3-foot hip-to-ankle anterior-posterior and lateral radiographs were obtained to assess alignment. Patients were instructed to record pain in the groin, buttock, thigh, or knee of the fractured extremity on a 10-point visual analog scale. The examiner specifically pointed to the areas of question to ensure patient understanding.
Results: Joint-related and musculoskeletal outcome scores improved gradually from the baseline assessment until the 6-month review. The WOMAC scores for pain, function, and stiffness improved gradually (P <0.001); SMFA scores improved from 64 ± 13 to 25 ± 20 (P = 2.422E-16). No further improvement was noted in any functional outcome measure at the 12-month interval compared with the 6-month assessment (P >0.2) Patients reported more pain at the knee (3.7 ± 3.1), compared with the thigh (2.5 ± 2.7), buttock (1.7 ± 2.7), and groin (1.0 ± 1.7) (P = 0.003). Pain and functional outcomes were plotted on scatter graphs, and correlations were performed with use of the Spearman rank test. Strongest correlations were noted between knee pain and WOMAC pain (0.748, P <0.001), function (0.701, P <0.001), and SMFA (0.733, P <0.001). Weaker correlations were noted between thigh, groin, and buttock pain and functional outcomes, with scores ranging from 0.2 to 0.55.
Conclusions: Recovery after femur fracture occurs most rapidly in the first 6 months following injury. Although residual deficits in functional outcome were still measurable 12 months after injury, improvements in functional outcome occurred predominantly in the first 6 months. Knee pain was the most common and most severe source of patient discomfort 6 months after isolated femur fracture. Knee pain demonstrated moderate-to-good correlation with general and joint-specific functional outcome measures. Pain around the hip was less significant in this study.
Significance: Disability is a known problem following femoral fractures. This study demonstrates that patients achieve most recovery in the first 6 months after injury. Furthermore, knee pain was the most common and severe source of patient discomfort and correlated with functional outcome. Knee pain is a major cause of prolonged disability after femoral shaft fractures and requires further investigation.