Kinematically Aligned TKA Provides Greater Functional Benefits Than Mechanical-ly Aligned TKA: A Case-Control Study

Objectives the kinematic alignment (KA) technique for total knee arthroplasty (TKA) and the medial pivot (MP) component design are two options promoting a physiologic prosthetic knee kinematics when used in combination that could improve TKA outcomes. Study aims to report about differences in functional outcome, alignment and in the risk of complications between KA and MA MP-TKAs .

Methods we performed a case-control study with prospectively collected data comparing consecutive 24 KA MP-TKA patients (13 females) with 24 matched MA MP-TKA patients. Patients were matched for sex, age (+/- 5 years), BMI (+/-5 Kg/m2), and the category of alignment. First condition of matching was varus deformity or valgus deformity and then they were matched within a deformity of plus or minus 5 degrees within the condition of being varus or valgus. Patients were treated for primary degenerative knee osteoarthritis and had no antecedent knee arthrotomy. The severity of the preoperative lower limb frontal deformity was not a criteria of inclusion/exclusion.

Results and Conclusion we found KA patients to have superior values in Forgotten Joint Score (FJS) at 2-weeks (KA 39 Vs. MA 23) and 1-year (KA 77 vs MA 51) follow-up. KA patients scored better and had higher improvements than MA patients for every section of the new Knee Society Score (KSS), and of the Knee Osteoarthritis Outcome Score (KOOS). Eleven out of 24 patients (46%) and 17/24 (70%) of KA patients, and 7/24 patients (29%) and 14/24 (58%) of MA patients had limb alignment non-neutrally aligned and orientation tibial component with more than 3° varus, respectively.

The KA of MP TKA design seems to have a good efficacy at early-term, with 1-year functional performance likely to be higher to the ones from MA MP TKAs.Further research is needed to define if those promising early results will last over time.

Stichwörter total knee replacement; kinematic alignment; medial pivot; functional outcomes

Publication History

Article published online:
15 October 2020