We present a prospective, randomised, single-centre, multi-surgeon, controlled trial comparing minimally invasive (MIS) and standard approach total knee arthroplasty (TKA).

86 patients undergoing 92 total knee replacements were recruited. 46 operations were randomised to the MIS treatment arm, 46 to the standard control arm. Data collected included postoperative blood loss, length of stay and complications. Patients underwent surgery via a quadriceps sparing or standard medial parapatella approach. All operations were performed using MIS instruments and an identical postoperative care pathway.

The MIS group had a significantly shorter length of stay (1.4 days, p=0.004) and fewer complications (p=0.003). Demographics, operative time blood loss and radiographic alignment were comparable between the groups. There were no deaths, pulmonary emboli or surgical site infections. 1 patient developed DVT and 1 required revision for pain and failure to regain flexion within 9 months of surgery, both in the control group. Nine percent of MIS patients versus 35% controls suffered a complication delaying discharge, of which 2% and 17% related to surgical site problems respectively.

MIS resulted in a shorter admission and fewer complications, whilst achieving satisfactory component alignment. We discuss the potential economic implications.