Title Anterior Prominence of the Femoral Condyle Varies among Prosthesis Designs and Surgical Techniques in Total Knee Arthroplasty

BackgroundPatellofemoral overstuffing after total knee arthroplasty can cause limited range of motion and anterior knee pain. This study compared anterior prominence of femoral components among different prothesis designs in surgical simulation models utilizing the anterior reference (AR) and posterior reference (PR) techniques.MethodsSurgical simulations were performed using preoperative computed tomography data of 30 patients on a three-dimensional planning system. Four implant models were used: Attune, Persona, Journey II, and Legion. Rotational alignment was set parallel to the transepicondylar axis and size selection was based on absence of notch formation in the femoral anterior cortex and best fit to the shape of the medial posterior femoral condyle. For each combination of surgical technique (AR or PR method) and implant model, measurements were taken of the maximum medial, central, and lateral prominence of the implant from the anterior femoral cortex (mm).ResultsUsing either the AR or PR method, the medial and central prominences were significantly lower with Journey II than with other models. The lateral prominence was the lowest with Attune in the AR method. The AR method was associated with significantly less prominence than the PR method, regardless of implant model.ConclusionsDegree of anterior prominence of the femoral implant is affected by implant design when the AR method is used. The PR method is associated with greater anterior prominence compared with the AR method, with size pitch an additional influencing factor. Journey II is associated with the least anterior prominence when using either method.