The Hindfoot Alignment in Total Knee Arthroplasty: A Systematic Review

Category: Hindfoot Introduction/Purpose: Patients with a hindfoot deformity pose a particular challenge when performing a total knee arthroplasty (TKA). This could be attributed to the lack of insights concerning hindfoot alignment outcome. Our objective was to perform a systematic review of the literature to investigate the influence of TKA on hindfoot alignment and vice-versa. Methods: This systematic review was performed in accordance to PRISMA guidelines; the original protocol is registered on PROSPERO (ID: 106980). The following electronic databases were searched to identify capable studies: Pubmed, EMBASE, Web of Science, Google Scholar, and Cochrane Library. To ensure the quality of the review, a quality assessment was performed according to the MINORS criteria. The mean MINORS score was 9.5 (range 7-12) and concurred with a good quality of the obtained studies. Results: Sixteen identified articles met the review criteria: six prospective cohort studies, nine retrospective studies, and one case-control study. Five articles reporting on clinical outcomes were identified; a pre-operative hindfoot deformity negatively influenced TKP outcome (N=4) or demonstrated no influence (N=1). Thirteen articles reporting on radiographic outcomes were identified. Five studies reported a significant improvement (P < 0.05) of hindfoot alignment after TKA, two studies demonstrated improvement limited to valgus hindfeet, seven studies observed a significant (P < 0.05) correlation between knee and hindfoot alignment, and two studies reported the association between hindfoot OA in patients undergoing TKA. Two studies reporting biomechanical outcomes were identified; these reported a shift of the weighbearing axis after TKA as a result of the remaining hindfoot deformity. Conclusion: TKA can improve the alignment of valgus hindfeet, but improvement was less pronounced in varus hindfeet. Furthermore, a worse clinical outcome is expected after TKA in patients with concomitant ankle OA. A remaining hindfoot deformity shifts the weightbearing axis, which could shorten the survival of the total knee prosthesis.