Unicompartmental knee arthroplasty in patients aged less than 65

Area of Science:

• Orthopedic surgery
• Arthroplasty research
• Biostatistics in healthcare

Background:

• Renewed interest in unicompartmental knee arthroplasty (UKA) for osteoarthritis.
• Increasing UKA use in patients under 65 reported, with initially low revision rates.
• Need to compare UKA usage and outcomes in younger patient demographics.

Purpose of the Study:

• To describe and compare the utilization and outcomes of UKA in patients younger than 65 years.
• To analyze combined data from Australian and Swedish knee registries for this demographic.
• To identify differences in revision rates based on age and sex within this cohort.

Main Methods:

• Analysis of over 34,000 UKA procedures (1998-2007), focusing on >16,000 patients under 65.
• Utilized survival analysis to determine revision outcomes.
• Endpoint defined as any reason for revision, stratified by age and sex.

Main Results:

• Both Australia and Sweden demonstrated a decline in UKA's proportion and absolute numbers per year.
• Seven-year cumulative revision risk for UKA in patients <65 was comparable between the two countries.
• Patients <55 years had a significantly higher 7-year revision risk (19%) than those aged 55-64 (12%); revision risk was similar between sexes.

Conclusions:

• Combined registry data indicate consistent UKA outcomes between Australia and Sweden for patients <65.
• Patients under 65 experience a higher revision rate compared to those 65 and older.
• Surgeons and patients must consider the elevated revision risk associated with UKA in younger individuals.