Soft tissue balance measurement in anterior cruciate ligament-resected knee joint: cadaveric study as a model for cruciate-retaining total knee arthroplasty

Abstract

BackgroundThe soft tissue balancing procedure remains a difficult issue during total knee arthroplasty, as much depends on the surgeon’s “feel.” Although computer-assisted navigation technology has been attempting to evaluate the joint stability, we have no definitive answer to an ideal soft tissue balance of the knee joint. The purpose of the present study was to determine the soft tissue balance in an anterior cruciate ligament (ACL)-resected normal knee joint throughout the range of knee flexion, which may provide reference data for cruciate-retaining total knee arthroplasty (TKA). MethodsWe investigated joint stability in 10 ACL-resected normal cadaver knees throughout the range of flexion under consistent joint distraction force using a specially developed tensioning device for TKA. We measured both medial and lateral joint gaps as the separation distance between the articular surfaces with 40lb (18.7kg) of joint distraction force. ResultsBoth medial and lateral joint gaps at 0° of flexion were significantly smaller than those at other flexion angles. The medial joint gap was almost consistent during knee flexion; however, the lateral joint gap increased with knee flexion and showed a significantly larger value at 60°–120° of flexion than the medial joint gap. ConclusionsThese characteristics of joint stability in the ACL-resected normal knee need to be taken into consideration in soft tissue balancing during cruciate-retaining TKA.