Functionality and Safety of an Ultra-Congruent Rotating Platform Knee Prosthesis at 5.6 Years: More than 5- Year Follow-Up of the e.motion® UC-TKA

Abstract

Background:Mobile bearing TKA prostheses were designed to minimize polyethylene wear by increasing implant conformity and reducing stresses between the articulating prosthesis components. It is the purpose of this study to assess the mid-term functionality and clinical outcome associated with a highly congruent mobile platform design, the e.motion® UC total knee prosthesis.Material and Methods:Functional and clinical outcomes were assessed after an average of 5.6 years (5.1 – 6.0 years) after total knee arthroplasty in 28 patients (24 women), aged 77.8±7.5 years. The Knee injury and Osteoarthritis Outcome Score (KOOS) was assessed. Secondary outcomes included the Knee Society Score (KSS), radiological evaluation of radiolucent lines and recording of adverse events.Results:The average KOOS subscore for the activities of daily life was 77.8 points after 5.6 years. Both the clinical and functional KSS improved at 2.4 and 5.6 years. Two patients showed radiolucent lines at 5.6 years. Adverse events over 5.6 years included 3 subluxations, 1 tilting and 1 misalignment of the patella. None of the prostheses were revised.Conclusion:This pilot study shows promising outcomes for the e.motion® UC prosthesis. In the small sample, the implant performed comparably to the LCS prosthesis (the gold standard). There were no loosenings or revisions observed at 5.6 years.

Functional Outcomes of a New Mobile-Bearing Ultra-Congruent TKA System: Comparison With the Posterior Stabilized System

“…Nonetheless, no notable differences were found for any type of adverse events between the two groups. Our finding is in accordance with previous studies reporting no increased incidence of adverse events with the e.motion-UC [38][39][40]. Our findings lead us to believe that the mobile-bearing UC prosthesis is a reasonably safe alternative to the mobile-bearing PS prosthesis when precise and meticulous surgical techniques are exercised.…”

“…This interesting finding is in agreement with previous studies reporting only a weak correlation between the postoperative maximum flexion and the clinical parameters for pain relief, joint function, and quality of life [41,42]. This study, along with previous midterm studies of TKAs performed with the e.motion-UC [38][39][40], indicates that the mobile-bearing UC prosthesis provides satisfactory functional outcomes.…”

“…As both prostheses were produced with identical design features by the same company, many confounding issues were reasonably dealt with in this study, allowing us to make a more valid comparison. A few studies have attempted to compare the clinical performance of the mobile-bearing UC prosthesis with the mobile-bearing PS prosthesis; however, the latter prosthesis was manufactured by a different company [38] or was considered for comparison from a previous study [39]. To the best of our knowledge, only one study has compared the clinical performance of the e.motion-UC and e.motion-PS prostheses from the same company.…”

Ultracongruent insert design is a safe alternative to posterior cruciate-substituting total knee arthroplasty: 5-year results of a randomized controlled trial

“…Despite the regular use of these UC inserts, there is only limited evidence about mid- or long-term outcome. Only few studies report 5- or 10-year results, none with an appropriate control group [ 3 , 10 , 18 ].…”

Comparison of ultra-congruent mobile- and fixed-bearing navigation-assisted total knee arthroplasty with minimum 5-year follow-up

“…Unlike fixed‐bearing systems, mobile‐bearing systems can theoretically reduce bearing wear by decreasing the stresses between the component and the polyethylene and decrease implant loosening by spreading the load to the soft tissue [5, 11]. However, few clinical studies to date have looked at this higher‐conformity design regardless of bearing type [16, 18], and only a few comparison studies of mobile and fixed UC designs have been reported [6, 15]. The purpose of this study was to retrospectively compare clinical and radiological outcomes as well as survival rates of the Columbus ® and e.motion UC knee systems after a minimum follow‐up period of 5 years.…”