Better short-term function after unicompartmental compared to total knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an established treatment option for patients with unicompartmental osteoarthritis (OA). However, strict patient selection is crucial for its success. The proposed advantages include nearly natural knee kinematics, faster rehabilitation and better functional outcomes. Despite the aforementioned facts and it's proven cost-effectiveness, there are still hesitations for the use of UKA as an alternative to total knee arthroplasty (TKA). Key objectives of this study were therefore to assess clinical and patient-reported outcome (PRO) as well as patient's satisfaction after medial UKA in comparison to TKA. METHODS: To assess the outcome after UKA we conducted a prospective multi-center study. 116 patients with unicompartmental OA and indication for UKA were included. Overall 54 females and 62 males with an average age of 62.7 years (±9.8) and an average body mass index (BMI) of 29.2 (± 3.7) were recruited. Clinical results and PRO were assessed using the Knee Society Score (KSS). Follow-ups took place 3 months, 1 and 2 years after surgery including clinical examination, radiographs, assessment of PRO and adverse events. Pain and satisfaction was evaluated using a visual analog scale (VAS, 0 (worst) to 10 (best)). For comparison with TKA a propensity score matched-pair analysis was performed to eliminate confounders. Matching criteria were gender, patient's age, BMI and comorbidities. A total of 116 matched-pairs were analysed. RESULTS: There was no revision in the UKA group until 2 years after surgery. Revision rates were higher in the TKA group (0.6%). Preoperative KSS-Scores were higher within the UKA cohort (p <  0.001). After surgical treatment, PROMs displayed a significant improvement (p <  0,001) in both cohorts. Regarding the Knee-Score (Pain, Alignment, ROM) we observed no differences between cohorts after 12 months. The Function-Score demonstrated significantly better results in the UKA cohort (UKA vs. TKA 95 vs 80, p <  0.001). Patient satisfaction was also higher in UKA patients (UKA vs TKA 9.0 vs 8.8, p = 0.019). CONCLUSION: Patients of both cohorts showed high satisfaction after knee arthroplasty. UKA resulted in higher function scores compared to TKA without increased revision rate during short-term follow-up. Therefore, UKA is a good treatment option for unicompartmental OA. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04598568 . Registered 22 October 2020 - Retrospectively registered.

Combined unicompartmental knee arthroplasty and anterior cruciate ligament reconstruction.

PURPOSE: Patients presenting anterior cruciate ligament (ACL) deficiency and isolated osteoarthritis of the medial compartment are treated either with biplanar osteotomy or with total knee arthroplasty (TKA). However, these patients between the forties and fifties are often very active in daily life and feel limited due to their knee. In order to follow the idea of preserving as much as possible from the joint, the concept of unicondylar joint replacement in conjunction with ACL reconstruction has been followed. There seems to be a limited experience with this concept. The purpose of the follow-up study was to evaluate the midterm clinical and functional outcome. METHODS: Twenty-seven patients were followed up for 53 months. The mean age of the 11 men and 16 women was 44 years. All patients were treated by combined unicompartmental knee arthroplasty and anterior cruciate ligament reconstruction. RESULTS: The Knee Society Score improved significantly from 77.1 ± 11.6 points to 166.0 ± 12.1 points (P ≤ 0.01). No revision surgery was required and no radiolucent lines were observed on the radiographs at the time of follow-up. The anterior translation showed less than 5 mm in 24 patients and 5 mm in the remaining 3 patients. CONCLUSIONS: The midterm clinical data have shown that combined surgery of UKA and anterior cruciate ligament reconstruction has revealed promising results. The restored knee stability seems to prevent the failure of UKA. However, long-term follow-up studies are required in these patients who received partial joint replacement fairly early in their life. LEVEL OF EVIDENCE: IV.