Fixed-bearing medial UKA is shown not to compromise outcomes for those with PF arthritis and ACL deficiency

Unicompartmental Knee Arthroplasty (UKA) is a less invasive alternative to total knee arthroplasty (TKA) for the treatment of end-stage arthritis^1-4.

The UKA is designed to preserve the bone and cruciate ligaments while providing better knee function, fewer complications and a shorter hospital stay. However, there is limited published data available to surgeons assessing knee function and patient satisfaction following UKA in patients with patellofemoral (PF) arthritis or anterior cruciate ligament (ACL) deﬁciency.

A study has been undertaken to determine whether medial/central PF arthritis or functionally stable ACL deﬁciency compromised the results of ﬁxed-bearing medial UKA at a minimum follow-up period of around 2 years. The possibility was that equivalent successful outcomes could be achieved in patients with or without substantial medial/central PF arthritis or functionally stable ACL deﬁciency. If this is proven to be the case, it will enable surgeons to make more informed decisions about which procedure is most appropriate for individual cases.

The authors studied a consecutive series of 229 patients (240 knees) after receiving ﬁxed-bearing medial UKA. Of the 240 knees, 125 (54%) had substantial medial/central PF arthritis and 21 (9%) functionally stable ACL deﬁciency. Various analyses of the patients involved revealed no association between outcomes and medial/central PF arthritis, and knees with functionally stable ACL deﬁciency were even associated with an improved physical function.

The study concluded that fixed-bearing medial UKA provides very successful outcomes for end-stage medial tibiofemoral arthritis, even in knees with substantial medial/central PF arthritis or functionally stable ACL deﬁciency. 97% of the patients in the study were satisﬁed or very satisﬁed with the result of their procedure at their 2-year follow-up. Longer-term prospective studies with larger sample groups are needed to conﬁrm these promising ﬁndings relating to outcomes in patients who may have previously been traditionally contraindicated for medial UKA.

¹Berger Y, Ftaita S, Thienpont E. Does medial patellofemoral osteoarthritis inﬂuence outcome scores and risk of revision after ﬁxed-bearing unicompartmental knee arthroplasty? Clin Orthop Relat Res 2019;477(9):2041–7.

²Lim J-A, Chen JY, Chong HC, Pang HN, Tay DKJ, Chia S-L, et al. Pre-existing patellofemoral disease does not affect 10-year survivorship in ﬁxed bearing unicompartmental knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2019;27(6):2030–6. doi: https://doi.org/10.1007/s00167-018-5169-y.

³Song E-K, Park J-K, Park C-H, Kim M-C, Agrawal PR, Seon JK. No difference in anterior knee pain after medial unicompartmental knee arthroplasty in patients with or without patellofemoral osteoarthritis. Knee Surg Sports Traumatol Arthrosc 2016;24(1):208–13. doi: https://doi.org/10.1007/s00167-014-3367-9.

⁴Deckard ER, Jansen K, Ziemba-Davis M, Sonn KA, Meneghini RM. Does patellofemoral disease affect outcomes in contemporary medial ﬁxed-bearing unicompartmental knee arthroplasty? J Arthroplasty 2020;35(8):2009–15. doi: https://doi.org/10.1016/j.arth.2020.03.007.

Report title

Medial/central PF arthritis and functionally stable ACL deﬁciency do not compromise outcomes of ﬁxed-bearing medial UKA

Report authors

Bull D, Mannan A, Ansari J, Mason K, London E, Müller J H, London N, The Harrogate Knee Study Group.