A matched comparison of long-term outcomes of total and unicompartmental knee replacements in different ages based on national databases: analysis of data from the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man

Journal article

Background
The 2 main treatment options for end-stage single compartment knee arthritis are unicompartmental (UKR) or total knee replacement (TKR). We compared the long-term outcomes in different age groups.
Methods
In total, 54,215 UKRs and 54,215 TKRs from the National Joint Registry and Hospital Episode Statistics database were propensity score matched and Kaplan-Meier and regression analysis used to compare revision, reoperation, mortality, and 3-month complications.
Results
UKR had higher 10-year revision rates (12% vs 5%, hazard ratio [HR] 2.31, P < .001) and 10-year reoperation rates (25% vs 21%, HR 1.12, P < .001). UKR had lower 10-year mortality rates (13.6% vs 15.5%, HR 0.86, P < .001). UKR had lower rates of medical (P < .001) and procedure related (P < .001) complications and deaths (HR 0.61, P = .02). If 100 patients had a UKR instead of a TKR then over 10 years, if they were <55 years old there would be 7 more reoperations and 1 less death; if they were 55-64 years old there would be 6 more reoperations and 2 more deaths; if they were 65-74 years old there would be 4 more reoperations and 2 less deaths; and if they were ≥75 years old there would be 3 more reoperations and 4 less deaths.
Conclusion
UKR has higher revision and slightly higher reoperation rates but lower mortality rates than matched TKR. The decision to do a UKR should, in part, be based on the balance of these risks, which are influenced by patient age. In the elderly group (>75 years) the data suggests that UKR compared to TKR has a greater absolute reduction in mortality than the increase in reoperation rate.

Authors: Mohammad, HR; Liddle, AD; Judge, A; Murray, DW

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Journal of Arthroplasty More from this journal
• Volume: 37
• Issue: 2
• Pages: 243-251
• Place of publication: United States
• Publication date: 2021-10-04
• Acceptance date: 2021-09-26
• DOI: 10.1016/j.arth.2021.09.018
• EISSN: 1532-8406
• ISSN: 0883-5403
• Pmid: 34619307
• Language: English
• Keywords: unicompartmental knee replacement; age; revision; reoperation; total knee replacement