Abstract
Ligament balancing is an integral part of total knee arthroplasty and is highly dependent on correct alignment of the knee in flexion and extension. The technique proposed begins with correct alignment of the articular surfaces of the femur both in flexion and extension so that the joint surfaces are perpendicular to the anteroposterior plane of the lower extremity. This is done separately on the femur and tibia in extension and flexion, irrespective of ligament contracture or stretching. Once alignment, sizing, and positioning of the implants are correct, the ligaments can be assessed. Only ligaments that are tight need to be released, thus minimising trauma and maximising stability of the knee.
Varus Knee: Knees that are tight medially only in flexion should first have the anterior portion of the medial collateral ligament (MCL) released, leaving the posterior oblique portion intact to provide stability in flexion and extension. Knees that are tight only in extension first should have release of the posterior oblique fibres of the MCL, and release of the posterior capsule if medial contracture persists in extension. This leaves the anterior portion of the MCL intact to stabilise the knee. Major destabilisation of the knee may occur if the posterior cruciate ligament (PCL) is released after full release of the MCL, release of posterior oblique fibres of the MCL, and posterior capsule release.
Valgus Knee: Knees that are tight laterally in flexion and extension first have release of the lateral collateral ligament (LCL) and popliteus tendon for tightness in flexion, then the iliotibial (IT) band and the lateral posterior capsule for any tightness in extension. For knees that are tight laterally only in extension, only the IT band and the lateral posterior capsule should be released. For knees that are tight laterally only in flexion, the LCL is released first, then the popliteus tendon. If all static lateral stability structures require release, the biceps femoris muscle, gastrocnemius muscle, and deep fascia can support the knee until capsular healing occurs.
The abstracts were prepared by Mrs Dorothy L. Granchi, Course Coordinator. Correspondence should be addressed to her at PMB 295, 8000 Plaza Boulevard, Mentor, Ohio 44060, USA.
