Mini-Subvastus versus Medial Parapatellar Approach in Total Knee Arthroplasty

Abstract

UNLABELLED: We compared short-term clinical results of the mini-subvastus approach with the standard parapatellar approach for total knee arthroplasty. Can one gain adequate access through the mini-subvastus approach without exceeding operating time, incurring additional complications, and maintaining correct implant geometry? In a prospective, observer-blinded study, 120 consecutive patients having total knee arthroplasty were operated on by one surgeon using either the mini-subvastus approach without patella eversion or the standard parapatellar approach with patella eversion. Patients were matched according to age, gender, body mass index, knee flexion, deformity, and pre-existing high tibial osteotomy. The mini-subvastus approach was technically more demanding. Reduced access and visibility prolonged the tourniquet time by an average of 15 minutes and led to two intraoperative complications. Patients in the mini-subvastus group lost on average 100 mL less blood and had better pain scores on day one [visual analogue scale (VAS): mean 2.4 versus 3.89]. They reached 90 degrees knee flexion earlier (2.8 versus 4.5 days), and an active straight-leg raise earlier (3.2 versus 4.1 days). Their average flexion at 30, 60 and 90 days was slightly better (100 degrees , 110 degrees , and 112 degrees versus 94 degrees , 106 degrees , and 109 degrees ). All patients including those with complications had good results with good component geometry and leg alignment. The mini-subvastus approach offers early but short-lived benefits for patients at the expense of a longer operation and a higher risk of complications. LEVEL OF EVIDENCE: Therapeutic study, Level II-1 (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.