Abstract
Total knee arthroplasty (TKA) has been established as a successful procedure for relieving pain and improving function in patients suffering from severe knee osteoarthritis for several decades now. It involves removing bone from both the medial and lateral compartments of the knee and sacrificing one or both of the cruciate ligaments. This in turn is likely to have an impact on the patients' functional outcome. In subjects where only one compartment of the knee joint is affected with osteoarthritis then unicondylar knee arthroplasty (UKA) has been proposed as an alternative procedure to TKA. This operation preserves the cruciate ligaments and removes bone only from the affected side of the joint. As a result there is the possibility of an improved functional outcome post surgery. UKA has been associated with faster recovery, good functional outcome in terms of range of motion and it is bone sparing compared to TKA. However, the biggest obstacle to UKA success is the high failure rates.
The aim of this study was to compare the functional outcome of computer navigated TKA (n=60) and UKA (n=42) patients 12 month post operation using flexible electrogoniometry. Flexible electrogoniometry was used to investigate knee joint kinematics during gait, slopes walking, stair negotiation, and when using standard and low chairs. Maximum, minimum and excursion knee joint angles were calculated for each task.
The biomechanical assessment showed statistically significant improvements in the knee kinematics in terms of maximum (p<0.0004) and excursion (p<0.026) knee joint angles in the UKA patient group compared to the navigated TKA group for each of the functional tasks. There was no statistically significant difference between the minimum knee joint angles during these functional tasks (p>0.05).
Therefore, UKA patients were showed to have a significantly better functional outcome in terms of the maximum knee joint angle during daily tasks. A limitation of this study is that it compares two cohorts rather than two randomised groups. It is expected that UKA patients will have a better functional outcome. Our results suggest that for patients with less severe knee osteoarthritis, UKA may offer a better functional outcome than the more common surgical option of TKA. The recent advancements in computer assisted and robotic assisted knee arthroplasty has the possibility to improve the accuracy of UKA and therefore led to the increase in confidence and in usage in a procedure which has the potential to give patients a superior functional outcome.
