Do different bearing designs of Unicompartmental knee arthroplasty make differences in long term survival rate, failure mode and clinical outcomes?
Author(s):
Seo S. (South Korea (ROK))
,
Seo S. (South Korea (ROK))
Affiliations:
Kim O.
Kim O.
Affiliations:
ESSKA Academy. Seo S. 05/09/18; 209626; P10-1446 Topic: Joint Replacement
Seung-Suk Seo
Seung-Suk Seo
Login now to access Regular content available to all registered users.

You can access free regular educational content on the ESSKA Academy by registering as an 'ESSKA Academy User’ here

Access to Premium content is currently a membership benefit.

Click here to join ESSKA or renew your membership.
Abstract
Discussion Forum (0)
Rate & Comment (0)
Objectives: Unicompartmental knee arthroplasty(UKA) has been more widely used for medial gonoarthritis. Recently used UKA implants include both fixed bearing (FB) and mobile-bearing (MB) designs. However, there has been little known regarding to which design provides superior long-term outcomes. The purpose of this study is to whether different bearing designs of UKAs induce differences in a long-term survival rate, failure mode and clinical outcomes.

Methods: We had performed 111 UKAs for medial gonoarthritis between 2002 and 2009, of which 44 knees had a MB design and 67 knees a FB design. 8 knees from MB design and 5 knees from FB design were lost during follow-up period. 2 patients from FB design expired. Patients with mobile-bearing UKA had a mean follow up of 8.3 year (range, 1-14.2 years); those with fixed-bearing UKA a mean follow up of 8.9 year (range, 1-14.1 years). Basic demographics between both groups did not show any differences. Patients were evaluated with clinical outcome scores using KOOS, revision rate and cause of revision.

Results: 5 of 36 (13.8%) MB knees were revised due to aseptic loosening, dislocation, and wear at a mean of 4.3 years, and 8 of 60 (13.3%) FB knees were revised due to aseptic loosening, infection, wear and arthritis progression at a mean of 7 years. Regarding to revision surgery as endpoint, the 7-year cumulative survival rates of the MB and FB designs were 0.917 (SE ± 0.0461) and 0.935 (SE ± 0.0312) and the 14-year cumulative survival rates 0.778 (SE ± 0.114) and 0.682 (SE ± 0.112), respectively. The differences in survival rates between MB and FB designs was not significant (log rank test p-value = 0.7287 at 7-years and p-value = 0.7886 at 14-years). The postoperative mean KOOS were comparable in the two groups.

Conclusions: This study showed that differences in survivorship and clinical outcomes between fixed and mobile bearing UKA did not demonstrate in a midterm and long-term follow up period. However, some causes of revision were different.

Keywords:
unicompartmental knee arthroplasty, survival rate, mode of failure, outcomes
Objectives: Unicompartmental knee arthroplasty(UKA) has been more widely used for medial gonoarthritis. Recently used UKA implants include both fixed bearing (FB) and mobile-bearing (MB) designs. However, there has been little known regarding to which design provides superior long-term outcomes. The purpose of this study is to whether different bearing designs of UKAs induce differences in a long-term survival rate, failure mode and clinical outcomes.

Methods: We had performed 111 UKAs for medial gonoarthritis between 2002 and 2009, of which 44 knees had a MB design and 67 knees a FB design. 8 knees from MB design and 5 knees from FB design were lost during follow-up period. 2 patients from FB design expired. Patients with mobile-bearing UKA had a mean follow up of 8.3 year (range, 1-14.2 years); those with fixed-bearing UKA a mean follow up of 8.9 year (range, 1-14.1 years). Basic demographics between both groups did not show any differences. Patients were evaluated with clinical outcome scores using KOOS, revision rate and cause of revision.

Results: 5 of 36 (13.8%) MB knees were revised due to aseptic loosening, dislocation, and wear at a mean of 4.3 years, and 8 of 60 (13.3%) FB knees were revised due to aseptic loosening, infection, wear and arthritis progression at a mean of 7 years. Regarding to revision surgery as endpoint, the 7-year cumulative survival rates of the MB and FB designs were 0.917 (SE ± 0.0461) and 0.935 (SE ± 0.0312) and the 14-year cumulative survival rates 0.778 (SE ± 0.114) and 0.682 (SE ± 0.112), respectively. The differences in survival rates between MB and FB designs was not significant (log rank test p-value = 0.7287 at 7-years and p-value = 0.7886 at 14-years). The postoperative mean KOOS were comparable in the two groups.

Conclusions: This study showed that differences in survivorship and clinical outcomes between fixed and mobile bearing UKA did not demonstrate in a midterm and long-term follow up period. However, some causes of revision were different.

Keywords:
unicompartmental knee arthroplasty, survival rate, mode of failure, outcomes
Code of conduct/disclaimer available in General Terms & Conditions

By clicking “Accept Terms & all Cookies” or by continuing to browse, you agree to the storing of third-party cookies on your device to enhance your user experience and agree to the user terms and conditions of this learning management system (LMS).

Cookie Settings
Accept Terms & all Cookies