J Korean Orthop Assoc.  2022 Oct;57(5):392-399. 10.4055/jkoa.2022.57.5.392.

Comparison of Survivorship between Unicompartmental and Total Knee Arthroplasty in the Same Patient

• Kim KT
• Lee S
• Kim JH
• Jung J
• Choi WJ

• KMID: 2534393
• DOI: http://doi.org/10.4055/jkoa.2022.57.5.392

Abstract

Purpose
To investigate and compare the survivorship of each surgery in patients with osteoarthritis of knees after performing unicompartmental knee arthroplasty (UKA) on one knee and total knee arthroplasty (TKA) on the other.
Materials and Methods
From January 2002 to December 2004, 51 patients with osteoarthritis of knees who underwent UKA on one knee and TKA on the contralateral knee were investigated for the cause of postoperative failure if any, and the survival rate using the Kaplan–Meier method. The Stratified Cox proportional hazard regression for matched-pair analysis was used to verify mutual significance and compare risks. Surgery was performed at intervals of one week during the same hospitalization period. The mean age at surgery was 64.2 years and the mean follow-up period was 12.7 years.
Results
Failures following the UKA occurred in 13 cases (25.5%). The causes of the failure included 4 cases of aseptic loosening, 3 cases of dislocation of mobile-bearing, 3 cases of lateral compartment osteoarthritis, 1 case of infection, and 2 cases of unknown cause. Failures following the TKA occurred in 3 cases (5.9%) including 2 cases of polyethylene wear and 1 case of infection. The cumulative survival rate of the UKA was 84.7% at 10 years and 69.6% at 15 years. The cumulative survival rate of the TKA was 97.9% at 10 years and 94.2% at 15 years. As a result of a comparative analysis of the survivorship between the two groups, it was observed that the risk of failure was 3.7 times higher in the UKA than in TKA, and there was a statistically significant difference in the survivorship (p=0.046).
Conclusion
When UKA and TKA were performed on both knees in patients with osteoarthritis of knees, the risk of failure of UKA was higher than that of TKA, and the survivorship was also significantly lower. Therefore, it is desirable to select an appropriate surgical method taking into consideration the degree of arthritis, the age of the patient, and other similar factors.

Keyword

knee joint; osteoarthritis; unicompartmental knee arthroplasty; total knee arthroplasty; survivorship