Mini-subvastus versus medial parapatellar approach in total knee arthroplasty

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.