Impact of modified subvastus approach versus limited medial parapatellar approach on early recovery after minimally invasive total knee arthroplasty: a retrospective comparative study

This study compared early clinical outcomes between a modified subvastus approach and a limited medial parapatellar approach in minimally invasive total knee arthroplasty. This retrospective comparative study included 90 patients who underwent primary minimally invasive total knee arthroplasty (TKA) between June 2019 and June 2020. Patients were divided into the modified subvastus group ( n = 45) and the limited medial parapatellar group ( n = 45) according to surgical approach they had actually received. Clinical outcomes included quadriceps functional recovery time, visual analog scale (VAS) pain scores, range of motion (ROM), Hospital for Special Surgery (HSS) knee scores, perioperative parameters, and postoperative complications. Baseline characteristics were comparable between the two groups. Operative time, incision length, drainage volume, postoperative hemoglobin level, transfusion rate, and functional outcomes at 6 months did not differ significantly between groups. Compared with the limited medial parapatellar group, the modified subvastus group had a shorter quadriceps functional recovery time (1.56 ± 0.92 vs. 2.07 ± 1.05 days, P = 0.01), lower VAS score at 24 h postoperatively (2.68 ± 0.83 vs. 3.26 ± 0.95, P < 0.01), and lower lateral retinacular release rate (0% vs. 17.8%, P < 0.01). ROM and HSS scores were significantly better in the modified subvastus group on postoperative day 6, but these differences were no longer significant at later follow-up assessments. No major complications were observed in either group. These findings suggest that both approaches can achieve satisfactory outcomes, but the modified subvastus approach may facilitate early postoperative rehabilitation after minimally invasive total knee arthroplasty. Further prospective studies with larger sample sizes and longer follow-up are needed to confirm these results.