Abstract
BACKGROUND: Minimally invasive knee arthroplasty seeks to diminish the problems of traditional extensile exposures aiming for more rapid rehabilitation of patients after surgery. QUESTIONS/PURPOSES: To determine if the subvastus approach results in less perioperative pain and blood loss, shorter hospital stay, and improved function at both early and long-term followup. METHODS: One hundred patients were enrolled in a prospective, randomized trial. Fifty were operated on using a minimally invasive subvastus approach and the other 50 by a conventional, peripatellar approach. Minimum followup was 3 years. A repeated-measures analysis of variance was used to compare the Knee Society score and range of motion during followup. RESULTS: The minimally invasive approach resulted in greater perioperative bleeding but no increase in transfusions. No differences were found in postoperative pain between groups nor did hospital stay show any differences. The range of motion on the third day after surgery was greater in the minimally invasive group. No differences were found in surgical time, femoral or tibial component orientation or outliers, or complication rates. Both Knee Society score and range of motion were superior using the minimally invasive subvastus approach during followup out to 36 months. CONCLUSIONS: The minimally invasive subvastus approach can result in improved long-term Knee Society scores and range of motion of total knee arthroplasty without increased risk of component malalignment, surgical time, or complication rate. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.