Primary resection of the posterior cruciate ligament does not produce a gap mismatch in the navigated gap technique

Abstract

Treatment of the posterior cruciate ligament (PCL) is a matter of continued controversy in total knee arthroplasty. By using so-called cruciate ligament-substituting implant designs, retention and resection of the PCL produce equivalent clinical results. However, it remains unclear whether primary resection of the PCL leads to relevant instabilities of the flexion gap. Especially when the increasingly popular navigated gap technique is used, this would result in a nonanatomic size selection and positioning of the femoral component and thus compromise the clinical outcome. The objective of this retrospective study was therefore to determine whether the navigated gap technique leads to a mismatch of the flexion and extension gap in primary routine resection of the PCL. In 92 patients consecutively enrolled in this study (92 knees), the flexion and extension gap were determined and documented after tibial resection, using the navigated gap technique navigation system (OrthoPilot 4.0; B. Braun Aesculap, Tuttlingen, Germany). The flexion gap was 10.4 ± 2.6 (2.5-19.5) mm; the extension gap was 10.4 ± 2.4 (5.5-17.5) mm. The individual difference was normally distributed around 0.0 ± 2.9 (-7 to 7) mm. In the navigated gap technique, primary routine resection of the PCL does not lead to a mismatch of the flexion and extension gap, so that a systematic nonanatomic resection of the femur can be ruled out.