Background/Purpose: To determine whether frailty is associated with clinical outcomes 1-year after total hip or total knee replacement, (TKR and THR).

Methods: Community-dwelling patients ≥65yo scheduled for elective TKR or THR were recruited from a musculoskeletal specialty hospital. Frailty was measured using validated criteria. A variety of instruments including Hip/Knee Injury and Osteoarthritis Outcome Score (HOOS/KOOS) and PROMIS-29 were administered pre-operatively and at 1-year. Preoperative dependence was measured with Katz ADL scores. Regression models were created by considering all variables which were significant at the 0.05 level in univariate models, and then performing backward selection to retain variables with 0.05 significance. Age and gender were forced in to all models.

Results: 740 subjects enrolled, 303 THR/437 TKR. Median age 72 years (range 65-94), 95.1% Caucasian, 63.5% female, 7.5% frail. 327 cases with 1 year data, (93% of eligible). There were no differences in percentage of frail and non-frail patients meeting OMERACT-OARSI responder criteria at 1-year, (p=0.09). In univariate analyses being frail was associated with worse HOOS/KOOS outcomes at 1-year in all subscales except HOOS pain; however, these relationships were no longer significant in multivariate analyses. Controlling for age, gender, and which joint was replaced, only pre-operative PROMIS-29 pain intensity predicted being an OMERACT-OARSI responder at 1-year, (OR 1.6; 95%CI 1.3-2.0). There were no predictors of being an OMERACT-OARSI responder in TKR. Interestingly, among THR, stronger baseline grip strength- a component of the frailty phenotype- was associated with decreased odds of being an OMERACT-OARSI responder, (OR 0.46; 0.23-0.93) and an increased likelihood of having worse HOOS pain at one year (p=0.02). Having fewer Katz ADL dependencies pre-operative strongly predicted better HOOS ADL scores at 1-year (p<0.001). No frailly components were associated with functional outcomes in TKR.

Conclusion: Frailty does not appear to be independently associated with 1-year outcomes in THR and TKR patients, although currently only a small absolute number of frail patients have completed 1-year follow-up. The finding that stronger grip strength is associated with worse outcomes is intriguing. Whether this reflects a ceiling effect of the OMERACT-OARSI responder criteria or is a clinically meaningful difference will be explored as the study progresses.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/is-frailty-associated-with-worse-outcomes-after-total-joint-replacements/