PCL balancing, an example of the need to couple detailed biomechanical parameters with clinical functional outcome

Excerpt

Although the results of a total knee replacement (TKR) are described as being good, many patients are not satisfied after the operation with certain limitations such as the inability to perform sports or other vigorous activities [10, 15]. This motivates engineers and surgeons in their search for superior implant materials and designs, leading to innovations such as surgical navigation and patient-specific cutting blocks, as well as high flex and anatomically formed knee designs. There is even a revival of interest for the bi-cruciate retaining knee implant. Besides these technical topics, the discussion about some more fundamental issues still continues. Still no consensus whether the posterior cruciate ligament (PCL) should be retained or substituted in TKR has been reached. Advocates for both PCL substitution and PCL retention can point to excellent clinical and radiographic results in the literature. Furthermore, findings in the area of biomechanics, histology, and gait analysis do not show convincing evidence for one technique above the other [11]. However, PCL balancing seems to be a factor of major importance. To function properly, the PCL must be accurately tensioned during TKR. This may seem evident, but clinical papers reporting on cruciate-retaining TKRs scarcely report on the functional status of the PCL or the contact point in the operated patients, even though several authors did discuss their finding that PCL insufficiency might be an explanation for some inferior results found for PCL-retaining implants [4, 14]. Thus far, little scientific data have been published regarding balancing issues related to the PCL, a topic generally considered to be complex. …