Comparison of Subvastus and Medial Parapatellar Approaches in Primary Total Knee Arthroplasty in Term of Clinical Outcome

Abstract

Background & objectives: The purpose of this study was to determine differences in clinical outcomes between subvastus and medial parapatellar approach in primary total knee arthroplasty.

Methods: This is a prospective randomized study; we compared the clinical results of primary total knee arthroplasty using Subvastus and medial Parapatellar approaches in 34 patients. The standard medial Parapatellar approach was used in 19 patients and Subvastus approach was used in 15 patients. The clinical outcome was assessed using a knee society score, time to return quadriceps function, and visual analog scale for pain. Results: The mean follow-up time was 3 months. Pain improved significantly over time in both groups. However, when comparing groups together, patients in subvastus group had better numerical visual analogue scale scores at 3^rd day postoperatively, nevertheless, no significant differences were found at other follow up times (8.11, 6.05, 4.26, 2.32, 1.47 for medial parapatellar group and 8.20, 4.47, 4.0, 1.67, 1.07 for subvastus group at preoperative, 3^rd day, 2, 6 and 12 weeks postoperative respectively for both groups). Subvastus roup had earlier return of quadriceps function by 1.9 days which was significant statistically. Knee society score improved significantly over time without any significant differences when comparing both groups together at any time of the follow-up periods (, 66.42, 105.21, 137.63, 155.53 for the medial parapatellar group and, 62.53, 107.53, 137.6, 155.81 for subvastus group at preoperative, 2, 6 and 12 weeks postoperative respectively for both groups). Conclusions: Subvastus approach allowed the earlier return of quadriceps function and less pain in the early postoperative day. In terms of physical and functional outcomes, none of the two surgical approaches showed an advantage over the other.