Electronic Thesis and Dissertation Repository

Thesis Format

Integrated Article

Degree

Doctor of Philosophy

Program

Health and Rehabilitation Sciences

Collaborative Specialization

Musculoskeletal Health Research

Supervisor

Bryant, Dianne M.

2nd Supervisor

Getgood, Alan M.J.

Co-Supervisor

Abstract

Purpose: The overall purpose of this thesis was to investigate response shift effects in patient reported outcome measures (PROMs) of symptoms, function, and quality of life after anterior cruciate ligament (ACL) injury and reconstruction.

Methods: This thesis includes three studies. Study 1 was a prospective cohort study designed with then-test methodology (using recalled and actual pre-operative scores) to detect the recalibration mechanism of response shift in the reporting of the two most common PROMs used with patients after ACL reconstruction. Study 2 was a qualitative study meant to elucidate young athletes’ definitions and perceptions of quality of life following an ACL injury, prior to surgical intervention. Study 3 was a one-year follow-up of Study 2 which allowed for detailed exploration of young athletes’ definition of quality of life and priorities one year after ACLR using qualitative methods and incorporating the then-test for self-reported quality of life ratings.

Results: Significant response shift effects were detected in patient reported outcomes after ACL reconstruction. Change in patient reported outcomes (treatment effects) were larger when recalled pre-operative scores were used in place of actual pre-operative scores (i.e., when both pieces of the change score were completed at the same time), suggesting that pre-post treatment effects may be commonly underestimated for PROMs. Patient perspectives on quality of life changed from pre- to post-operative through processes of recalibration, reframing, reprioritization, reconceptualization, and self-reflection.

Conclusions: Response shift was detected in PROMs from pre-operative to one year post-operative following ACLR, at both a group and individual level. Mechanisms of recalibration, reprioritization, and reconceptualization were identified as contributing to response shift. Overall, this work calls into question the utility of traditional pre-post intervention change scores for PROMs following ACLR, highlighting the need for novel approaches to subjective outcome assessment and rigorous studies that can accurately evaluate both patient reported outcomes and patient-important event outcomes.

Summary for Lay Audience

Anterior cruciate ligament (ACL) ruptures are one of the most common knee injuries, especially in young active individuals. Following ACL injury, ACL reconstruction (ACLR) procedures are commonly performed with the goal of minimizing symptoms and improving function, sport participation, and quality of life. These outcomes are measured before and after surgery using questionnaires called patient reported outcome measures (PROMs). However, individuals may change how they think about the outcomes being measured, a phenomenon labelled response shift. If response shift effects are present, we cannot confidently compare scores over time. This thesis is composed of three studies designed to identify and investigate response shift effects in PROMs after ACL reconstruction.

Study 1 compared the improvement in PROM scores after ACLR from pre- to one year post-operative when change was calculated using actual pre-operative scores versus when using recalled pre-operative scores (completed one year post-operatively).We found that change scores were larger when recalled pre-operative scores were used, suggesting traditional change scores may underestimate patient perceived improvement after ACLR.

Study 2 asked young athletes with ACL injuries about their definitions of quality of life (QOL) and their self-reported QOL following injury while waiting for ACLR. We identified four common components that defined young athletes’ QOL: social support, sport, health, and independence. Athletes who focused on QOL components relatively unaffected by injury had higher QOL scores than those who focused on losses associated with the injury.

Study 3 was a follow-up of study 2, in which the same young athletes were interviewed one year post-operatively to investigate if their perspective on QOL had changed. The athletes also complete post-operative and recalled pre-operative QOL scores. We identified that athletes reconceptualized QOL based on how they prioritized sport within their global quality of life one year after surgery. On average, improvements in QOL were larger when using the recalled pre-operative scores instead of actual pre-operative scores.

Response shift effects were identified in PROM scores one year after ACLR. This means that traditional ways of measuring change may not be an accurate reflection of how symptoms, function and quality of life are improving after ACLR.

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

Available for download on Thursday, July 23, 2026

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