Surgical Technique: Lateral Retinaculum Release in Knee Arthroplasty Using a Stepwise, Outside-in Technique

Abstract

Lateral release of a tight lateral retinaculum in a TKA is intended to correct patellar maltracking but the widely used inside-out technique has associated risks. We describe an alternate stepwise outside-in technique, with titrated release intended to maximize the chance of preserving the superior lateral genicular artery (SLGA). Patellar maltracking was judged by a no-thumb technique and graded as I and Ia: normal and near normal tracking; II: patella tilted; III: patella subluxed; or IV: patella dislocated. Outside-in release was performed in three progressive steps. Step-1 release was from the midpatella to the upper tibial border, Step-2 release was from the midpatella to the proximal pole of the patella, and Step-3 release was proximal to the superior pole of the patella with sectioning of the SLGA. We retrospectively reviewed records of 1884 patients operated on between 2002 to 2008. Two hundred five patients (11%) had lateral release performed, and 177 of those 205 patients (86%) were reviewed. Patellofemoral function was assessed clinically by The Knee Society score. Radiographs were examined for patellar tilt, shift, and avascular necrosis. The minimum followup was 22months (median 48months; range, 22-105months). The SLGA was preserved in 155 (76%) patients. At last followup, no patient had patellar maltracking, patellar fracture, or avascular necrosis. Six of 177 (3%) patients had anterior knee pain. Female patients and high-flex components had a higher incidence of release and midvastus arthrotomy had a lower incidence of release. Stepwise release of the lateral retinaculum by an outside-in technique allowed minimum necessary retinacular release, preserving the SLGA in 76% of patients. No complications were seen at followup with functional and radiographic examinations. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.