Total knee arthroplasty performed with either a mini-subvastus or a standard approach: a prospective randomized controlled study with a minimum follow-up of 2 years.

Background: There is currently a trend toward minimally invasive total knee arthroplasty (TKA) to decrease the morbidity related to the standard approach. The aim of our study was to clarify whether the mini-subvastus surgical had an advantage over the standard in term of pain level, blood loss, and postoperative recovery, whether the mini-subvastus surgical was prone to radiographic malalignment, prolonged operative time, and increased complications.

Methods: In a prospective randomized study, we compared the clinical and radiological results of primary TKA using a mini-subvastus approach or a standard approach in 68 patients. The mini-subvastus approach was used on 35 patients (group I) and the standard approach on 33 patients (group II).

Results: The mean follow-up was 28 months (range 24-36 months). Patients in group I had less blood loss and better visual analogue scale score at 1 day postoperatively. They achieved active straight leg raise earlier and underwent less lateral retinacular releases. The mean Knee Society function score, Oxford knee score, and range of movement were significantly better in group I up to 9 months after surgery (all, p < 0.05). However, there were no significant differences in these parameters between the groups at final follow-up. Reduced access and visibility in group I prolonged tourniquet time by an average of 22 min and resulted in five technical errors on radiographic evaluation.

Conclusions: Patients can receive marked but temporary benefits from the mini-subvastus technique, with a definite cost: that of component malposition and prolongation of operative time.