Several studies have described the relationship between the joint line and bony landmarks around the knee. However, high inter-patient variation makes these absolute values difficult in use. This study was set up to validate the previously described distances and ratios on calibrated full limb standing X-rays and to investigate the accuracy and reliability of these ratios as a tool for joint line reconstruction One hundred calibrated full-leg standing radiographs obtained from healthy volunteers were reviewed (fig 1). Distances from the medial epicondyle, the lateral epicondyle, the adductor tubercle, the fibular head and the proximal center of the knee (CJD) to the virtual prosthetic joint line were determined (fig 3). This prosthetic joint line was created by introducing a virtual distal femoral cutting block with a valgus angle of 6° on the full-leg radiographs. The adductor ratio was defined as the distance from adductor tubercle to the joint line divided by the femoral width. The correlation with the femoral width, the CJD and the limb alignment was analysed using linear regression analysis. The accuracy and reliability of the use of the ratio of the distance of the adductor tubercle, the medial epicondyle and the CJD relative to the femoral width to reconstruct the joint line was calculated.Introduction
Methods:
IN THE PAST success of TKA has been measured by ROM with maximum flexion as a bench mark, along with good stability of the knee joint MAINLY IN EXTENSION. Due to changing demographics our TKA population has shifted to more active and demanding patients which want to return to normal daily living, including professional and recreational sports activities. With the patella in place, we define a ligament “balanced resection” technique using the elibra device, and are able to optimize our results and meet younger, more active patient's expectations. Our workflow consists of a flexion gap first technique, maximizing posterior condylar offset, hence maximizing flexion with optimal ligament balance. This flexion gap is then transmitted to the extension gap, initially using custom made spacer blocks either neutral or angled in 1°, 2° or 3° applied to the elibra sensing device and more recently by using a specific designed extension gap balancer. The immediate and short term postoperative observations concerning femoral component rotation, patellar tracking, influence of patella in place versus subluxed on flexion gap balance, varus-valgus alignment and complete mitigation of ligament releases will be discussed.
