Mini-incision total knee arthroplasty can increase risk of component malalignment.

UNLABELLED: Interest in minimal-incision total knee arthroplasty has increased in recent years. We compared a group of 30 patients who had total knee arthroplasty with a mini-incision to a similar group of 30 patients who had total knee arthroplasty with a standard length incision. The minimal-incision group had some minor early advantages (less pain medication use, earlier improvement in range of motion), but these advantages dissipated by 3 months followup. Radiographic evaluations showed that four of the 30 patients with minimal incisions had tibial component varus malalignment (< 87 degrees ), whereas no patients with the standard length incision had malalignment. Although total knee arthroplasty performed using a minimal incision may provide some early advantages, minimal incisions can impede a surgeon's vision and may influence component alignment and possibly compromise long-term outcome. LEVEL OF EVIDENCE: Therapeutic study, Level III-1 (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.