Criteria for Implant Fit Assessment in Total Knee Arthroplasty – A Review

Abstract

Patient satisfaction in total knee arthroplasty is still limited and lower compared to patient satisfaction in total hip arthroplasty. While there are multiple influence factors for patient satisfaction, implant design is one aspect to consider. In clinical practice, the patient-specific assessment of implant fit is limited to a matching of the anteroposterior and mediolateral size, based on X-rays. Hence, the goal of this review was to identify other potential criteria for a patientspecific implant fit evaluation. A literature review was performed in PubMed. Inclusion criteria were a patientspecific assessment of knee implant components, a comprehensible motivation or a statistically proven relationship with an outcome measure, and a clear method description. Implant fit was considered not only as a matching of size, shape and interface, but also to include the implant’s (rotational) alignment, as proposed by Dai et al. (2014). Several studies reported a statistically significant relationship of implant fit criteria with outcome measures. Many more studies proposed fit criteria, motivated by a potential relationship with outcome measures. Most criteria assessed the bone-implant interface, second the morphology of the articulating surfaces and third the component and resulting bony alignment. Obstacles for the assessment of the criteria identified is the limited availability of 3D surface models in TKA. However, with new imaging technologies this availability is likely to increase. The decision process regarding the implant in TKA could be supported by a comprehensive automated fit analysis of several designs and/or sizes. An adequate matching of the implant to the respective patient may improve patient satisfaction.

Keywords

• implant fit
• bone-implant mismatch
• total knee arthroplasty