Comparing the Sub-Vastus and Medial Parapatellar Approaches in Total Knee Arthroplasty: A Meta-Analysis of Short-Term Outcomes

Proponents of the Sub-Vastus (SV) approach in primary Total Knee Arthroplasty (TKA) claim superior extensor mechanism function which results in earlier recovery after surgery. We performed a meta-analysis of randomized controlled trials comparing the SV and standard Medial Parapatellar (MPP) approaches in primary TKAs. The study was performed using the Cochrane handbook for systematic reviews guidelines. A total of 28 studies with 2171 patients were included and the mean age of the SV group was 68.2 [standard deviation, ±4.4] and of the MPP group was 68.4 (±3.85). The SV approach resulted in a significant improvement in flexion at day 3 postoperatively [mean difference (MD) = 6°; 95% confidence interval (CI), 0.37–11.71; p < 0.01], but this was not sustainable at 6 weeks, 3 months, and 12 months postoperatively. Similarly, despite a significant reduction in the visual analogue scale score at day 1 postoperatively (MD = −1.19; 95% CI, −1.70 to −0.68; p < 0.01), there was not enough evidence to support its superiority after that. The SV approach led to a reduction in days to straight leg raise (MD = −1.88; 95% CI, −2.45 to −1.31; p < 0.01) and lateral releases [relative risk = 0.49; 95% CI, 0.30–0.82; p < 0.01) with no difference in complication rates ( p = 0.64) but at the expense of a prolonged operation (MD = 13 min; 95% CI, 9.41–16.69; p < 0.01). Our conclusion is that the SV approach provides an alternative to the MPP with some advantages in the first 3 days only after primary TKA surgery.