Conference Coverage

Partial and Total Knee Arthroplasty Show Similar Recovery Timelines

Edited by:
Ashton L. Stahl

Key Highlights

  • Meaningful improvement rates were comparable for 2 of 3 patient-reported outcome measures.
  • Both groups reached meaningful improvement within approximately 0.8–1.6 months, with no significant differences in timing.
  • Unicompartmental knee arthroplasty had higher conversion/revision rates, whereas total knee arthroplasty had higher rates of other reoperations.

A propensity-matched retrospective cohort study being presented at the American Association of Hip and Knee Surgeons (AAHKS) 2026 Annual Meeting found that patients undergoing unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA) achieved clinically meaningful functional recovery within similar timeframes. Although improvement rates were comparable on 2 patient-reported measures, UKA patients were more likely to achieve meaningful improvement on a third measure.

The researchers examined whether differences in early recovery translated into clinically meaningful improvements, using the minimal clinically important difference (MCID). They analyzed a multi-institutional database covering 2016–2025 and included adults undergoing UKA or TKA with at least 2 years of follow-up. We matched patients using a 1:5 UKA approach based on age, sex, body mass index, Charlson Comorbidity Index, and the American Society of Anesthesiologists classification.

We calculated distribution-based MCIDs for the Knee Injury and Osteoarthritis Outcome Score Physical Function Short-form (KOOS-PS), Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical Health, and PROMIS Physical Function Short-form 10a (PF-10a). The investigators assessed time to MCID using non-interval-censored and interval-censored survival analyses and categorized reoperations at 2 and 5 years.

Study Findings

The analysis included 1,738 UKA patients and 8,206 TKA patients. MCID achievement rates were comparable for KOOS-PS (73.3% versus 70.2%, P = .111) and PROMIS Global Physical Health (65.4% versus 67.1%, P = .591). However, UKA patients were more likely to achieve MCID for PROMIS PF-10a: 77.6% versus 72.0% among TKA patients (P = .002).

Interval-censored analyses showed that both groups achieved MCID within approximately 0.8–1.6 months across all 3 measures, without significant between-group differences. For reoperations categorized at 2 and 5 years, the abstract reported higher conversion/revision rates with UKA than TKA (3.1% vs 1.3%; P < .001). Other reoperations were more frequent with TKA than UKA (4.5% vs 2.6%; P = .014), predominantly manipulation under anesthesia. Separate percentages for each follow-up time point were not provided.

Clinical Implications

According to the study authors, the findings provide useful data for perioperative counseling by describing meaningful functional recovery and differences in subsequent procedures. Their conclusion emphasized comparable recovery rates and timeframes alongside higher conversion/revision rates after UKA and higher rates of other reoperations after TKA.

Expert Commentary

“UKA and TKA patients achieve meaningful functional recovery at comparable rates and timeframes. Although UKA was more likely to be converted/revised, TKA had a greater rate of other reoperations. These findings provide useful data for perioperative counseling,” the researchers concluded.

Reference

Melnic CM, Williams DL, Bedair HS, Bono O, Singh R, Ibrahim Z. Comparing time to meaningful recovery after unicompartmental vs. total knee arthroplasty. Abstract for: American Association of Hip and Knee Surgeons Annual Meeting; November 5-8, 2026; Dallas, TX.