Introduction:Up to 33% and 25% of patients with end-stage hip and knee osteoarthritis (OA) are
considered frail by the Groningen Frailty Indicator (GFI). This study aims to assess
whether frail patients have lower functional gains after arthroplasty and to assess GFI
as a tool to discriminate between good and adverse change score.Materials and Methods:Patients with end-stage hip/knee OA scheduled for arthroplasty were recruited from the
Longitudinal Leiden Orthopaedics Outcomes of Osteo-Arthritis Study.
Functional outcome was measured as change score on the Hip Osteoarthritis Outcome
Score/Knee Osteoarthritis Outcome Score (HOOS/KOOS), by subtracting preoperative score
from 1-year postsurgery score and then dichotomized based on a cutoff of 20 points. For
each HOOS/KOOS subscale, 3 models were estimated: GFI univariate (model 1), GFI and
baseline score (model 2), and baseline score univariate (model 3). A receiver operating
characteristic analysis was performed to assess the discriminative ability of each
model.Results:Eight hundred five patients with end-stage hip OA (31.4% frail) and 640 patients with
end-stage knee OA (25.4% frail) were included. Frail patients were older, had a higher
body mass index, had more comorbidities, and lived more often alone. Persons considered
frail by GFI had significant lower baseline score; however, except for “function in
sports and recreation” and “quality of life,” change scores were similar in frail and
nonfrail persons. The discriminatory value of GFI was negligible for all HOOS/KOOS
subscales. Baseline score, however, was adequate to discriminate between total knee
arthroplasty patients with more or less than twice the minimally clinically important
difference on KOOS symptoms subscale (area under the curve = 0.802).Discussion/Conclusion:Although frail patients with OA have lower functioning scores at baseline, the change
scores on HOOS/KOOS subscales are similar for both frail and nonfrail patients.
Exploring other heath assessements may improve patient-specific outcome prediction.