Function is better with fixed-bearing vs mobile-bearing UKA
Oxford Knee Score improvements after fixed-bearing unicompartmental knee arthroplasty were associated with more meaningful patient outcomes vs. those for mobile-bearing unicompartmental knee arthroplasty, study results showed.
“Our study suggests the registry results of lower revision rate are also coupled with an improvement in patients’ outcomes” with fixed-bearing unicompartmental knee arthroplasty, Jonathan Coward said at the Virtual EFORT Congress.
Coward, an orthopaedic registrar at Joondalup Health Campus in Joondalup, Australia, presented results of a study that compared function and satisfaction at 3 months and 1 year postoperatively for 90 patients treated with the cementless Oxford Unicompartmental Knee System (Zimmer Biomet) implant and 90 patients treated with the newer modular, cemented balanSys UNI (Mathys) implant at a single center. Two experienced surgeons performed the implantations, and patients were matched for age, gender and BMI. Some bilateral cases were included in the study population.
“Currently, the Oxford is the most widely used implant around the world, but balanSys does seem to have a lower revision rate and our question was whether or not this related into better patient outcomes,” Coward said, noting both prostheses are used for medial unicompartmental arthroplasty to treat isolated medial compartment osteoarthritis, however the Oxford implant has a mobile bearing and the balanSys has a fixed bearing.
For the preoperative and follow-up outcome measures, researchers used the Oxford Knee Score (OKS), pain rated on a scale of 1 to 10, knee range of motion and patient satisfaction on a five-point Likert scale.
Results showed patient satisfaction at 3 months and 12 months postoperatively was greater with the balanSys implant at 92% and 88.5%, respectively, than with the Oxford system at 84.6% and 79.2%, respectively. “Although, this is not statistically significant at this point,” Coward said.
“Our most pertinent finding was that the change in OKS between the balanSys was significantly improved vs. patients with the Oxford, by five points, which was shown to have a meaningful difference in outcomes for patients,” he said.