Comparison of knee function after antegrade and retrograde intramedullary nailing for diaphyseal femoral fractures: results of isokinetic evaluation.

OBJECTIVE: To evaluate knee function in patients having femoral diaphyseal fractures treated with antegrade or retrograde intramedullary nail insertion. DESIGN: Prospective. SETTING: Level I referral center. PATIENTS AND METHODS: Seventy patients having 71 OTA 32 fractures were randomly allocated into 2 groups to be treated with either antegrade or retrograde intramedullary nails inserted with reaming. INTERVENTION: Antegrade nail in 41 fractures and retrograde femoral intramedullary nails in 30 fractures. MAIN OUTCOME MEASURES: Postoperative knee range of motion, Lysholm Knee Score, and isokinetic knee muscle function testing at least 6 months after documented fracture healing, minimum 1 year postoperatively. RESULTS: Groups had similar data with regard to demographics and injury patterns. Mean follow-up time was 44 (range: 25-80) months. Mean knee flexion angle was 132 and 134 degrees, and mean Lysholm Score was 84 and 83.1 in antegrade and retrograde groups, respectively (P = 0.893 and P = 0.701). Isokinetic evaluation revealed similar results for peak torque deficiencies at 30 and 180 degrees per second and total work deficiencies at 180 degrees per second (P > 0.05). Age affected the knee functioning as the higher the age of the patient is, the lower the Lysholm Score and knee flexion angle (r = -0.449, P = 0.0321 and r = -0.568, P = 0.001, respectively). CONCLUSIONS: Knee function seems to have similar clinical results after either antegrade or retrograde nail insertion for femoral diaphyseal fractures when knee range of motion, Lysholm Scores, and isokinetic knee evaluation are considered as outcome measures. With increasing patient age, a decrease in knee functioning should be anticipated in patients with femoral fractures treated with intramedullary nails regardless of technique.