Unicompartmental versus total knee arthroplasty database analysis: is there a winner?

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Reconstructive Surgery

Background:

• Total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) are surgical options for knee osteoarthritis.
• Surgeons often assume UKA yields superior function, but this is based on final scores, not score changes, and UKA patients often have higher pre-operative scores.

Purpose of the Study:

• To compare the change in clinical outcome scores between TKA and UKA.
• To evaluate and compare the survivorship of TKA versus UKA.

Main Methods:

• A retrospective review of 5606 TKAs and 279 UKAs performed between 1978 and 2009.
• Comparison of pre-operative, post-operative, and change in Knee Society Clinical Rating System (KSCRS), SF-12, and WOMAC scores.
• Analysis of cumulative revision rates and Kaplan-Meier survivorship.

Main Results:

• Both TKA and UKA showed similar changes in WOMAC and total KSCRS scores.
• TKA patients had higher knee scores, while UKA patients had higher function scores post-operatively.
• UKA had a higher cumulative revision rate (13%) than TKA (7%), with TKA showing better 5- and 10-year survivorship.

Conclusions:

• Despite higher pre- and post-operative scores in the UKA group, the functional improvement (change in scores) was comparable to TKA.
• TKA demonstrated superior long-term survival rates compared to UKA, suggesting a potential advantage in durability.