Improved Pain and Function, Low Complication Rates, and 95% Patient Satisfaction at 2 Years After Medially Stabilized Total Knee Arthroplasty: A Prospective Multicenter Cohort Study.

BACKGROUND: The medially stabilized (MS) knee concept has gained wider acceptance in recent years. However, to date, there is inconsistent evidence for its merits over traditional total knee arthroplasty (TKA) designs. The aim of this study was to assess the clinical performance of a second-generation medially stabilized knee obtainable by multiple, independent surgeons in a general TKA population. METHODS: Fifteen surgeons (16 hospitals) participated in this prospective nonrandomized cohort study of 568 patients (608 knees). Demographics represented a standard primary TKA population. Data were collected for baseline characteristics and outcome measures at 6, 12, and 24 months postoperatively for range of motion, the Knee injury and Osteoarthritis Outcome Score, Oxford Knee Score, EuroQol 5-Dimension visual analog scale, University of California Los Angeles activity score, Forgotten Joint Score, patient satisfaction scores, and complications. RESULTS: Overall, 548 TKAs were included in the final 2-year follow-up (90.8% follow-up). The revision rate at 2 years was 0.99% (6 knees revised). All measures reported significant improvement from preoperative to 24 months (P < .0001), with good range of motion (119°) and high mean scores, including Oxford Knee Score 42 and Forgotten Joint Score 70. At 2 years, the median satisfaction score was 9.3, 95.7% of patients reported that their problems were better and 94.5% of patients responding that the results of their operation were good, very good, or excellent. CONCLUSIONS: We found that use of a second-generation MS knee design by multiple surgeons can produce excellent outcomes, with low complication rates and higher levels of patient satisfaction, than those reported in the literature for traditional TKAs. This study represents the largest cohort, multisurgeon, prospective study reported in the literature for the introduction of a new generation MS TKA and supports its wider adoption.