Comparison of subvastus and medial parapatellar approaches in primary total knee arthroplasty in term of clinical outcome

Background & objectives: The purpose of this study was to determine differences in clinical outcome 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 used in 19 patients and Subvastus approach used in 15 patients. Clinical outcome assessed using knee society score, time to return quadriceps function and visual analogue scale for pain. Results: The mean follow-up time was 3 months. Pain improved significantly overtime in both groups. However, when comparing groups together, patients in subvastus group had better numerical visual analogue scale score at 3rd day postoperatively, nevertheless, no significant differences 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, 3rd day, 2, 6 and 12 weeks postoperative respectively for both groups). Subvastus group had earlier return of quadriceps function by 1.9 days which was significant statistically. Knee society score improved significantly overtime 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 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 earlier return of quadriceps function and less pain in the early postoperative day. In term of physical and functional outcome, none of two surgical approaches showed advantage over the other