Comparing early functional outcomes between the midvastus and medial parapatellar approach for total knee...

The medial parapatellar approach is the most prevalent approach for total knee arthroplasty. However, recent studies have suggested that the midvastus approach may confer benefits of better functional outcomes in the early post-operative period. This study aims to explore the differences in early functional outcomes between the two approaches.

This is a prospective cohort study of 72 total knee arthroplasties performed in a single tertiary institution. Baseline demographics and functional status were collected. Patients were followed up at the following time points - post-operative day 0, 1, 2, day of discharge and at first follow up 4-6 weeks post-surgery. The primary outcomes were range of motion, ambulatory distance, use of mobility aids, ability to straight leg raise and quadriceps strength - adjuncts to approximate functional recovery. Secondary outcomes include pain scores, operative time, length of stay, presence of any peri-operative complications, and patient discharge destination.

Patients in the midvastus group achieved a greater ambulatory distance on post-operative day 1 compared to those in the medial parapatellar group (median ambulation distance 30m versus 18m, p < 0.001). The time to straight leg raise was also shorter in the midvastus group (median duration 0 days vs 1 day, p = 0.016). There was no significant difference in length of stay, operative time or incidence of peri-operative complications.

The midvastus approach showed non inferior outcomes when compared to the classic medial parapatellar approach and may confer additional functional benefits in the form of shorter time to straight leg raise and longer ambulatory distances on post-operative day 1. Clinicians need to balance the purported benefits of the midvastus approach with the intraoperative technicalities of the midvastus approach, before deciding if it is suitable to be a standard approach to the knee in total knee arthroplasties.