Does Recalibration Response Shift Alter Perceived Treatment Effects in Patient-Reported Outcomes After Anterior...

Patient-reported outcome measures (PROMs) are used longitudinally after anterior cruciate ligament reconstruction (ACLR). However, PROM scores depend on patients' perspectives, which are likely to change over time, particularly after a health-related event. This phenomenon, known as recalibration or "response shift," may limit our ability to accurately interpret PROMs.

To identify whether recalibration response shift effects are present in PROM scores after ACLR and to investigate the influence of coping styles and life events on outcomes and recalibration response shift after ACLR.

Cohort study; Level of evidence, 2.

Patients having primary ACLR were recruited to complete the Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee Form (IKDC SKF) preoperatively and 1 and 2 years postoperatively. At both postoperative time points, patients completed a second KOOS and IKDC SKF based on their recollection of preoperative status, as well as brief COPE (Coping Orientation to Problems Experienced) and life event questionnaires. Unadjusted change (traditionally measured change), adjusted change (accounting for the patient perspective), and the magnitude of the recalibration response shift (the difference in change scores) were calculated for all outcomes, along with the proportion of patients exhibiting meaningful positive recalibration, meaningful negative recalibration, or no meaningful recalibration. Linear regression analyses evaluated the influence of coping strategies and life events on postoperative PROM scores and the magnitude of recalibration response shift.

Of 171 participants (mean age, 24 years, 56% male), 158 (92%) and 146 (85%) completed 1 and 2 years follow-up, respectively. Adjusted change was significantly greater than unadjusted change (P < .05) for all PROM scores except KOOS Sport at 1 year postoperatively (P = .17), with the magnitude of recalibration response shift ranging from 3 to 18 points. Three-quarters of participants' scores indicated a meaningful shift in response in at least 1 PROM. Coping and life event variables predicted follow-up PROM scores but not the magnitude of recalibration response shift.

A meaningful recalibration response shift was clearly identified in IKDC SKF and KOOS scores 1 and 2 years after ACLR. Traditional within-patient change scores do not reflect participants' perceived change in constructs after ACLR, and recalibration response shifts may alter perceived treatment effects (both over- and underestimation).