Patient-reported outcome measure thresholds differed by TSA type, diagnosis
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TAMPA, Fla. — Researchers who identified differences in clinically relevant results for anatomic and reverse shoulder arthroplasty said understanding these prosthesis- and diagnosis-based differences can aid clinical decision-making.
Josie A. Elwell, PhD, presented the findings at the Orthopaedic Research Society Annual Meeting, here.
Elwell and colleagues studied whether diagnosis and indications affect patient-reported outcome measures (PROMs) for primary anatomic total shoulder arthroplasty (aTSA) and reverse TSA (rTSA) when minimal clinically important difference (MCID), patient-acceptable symptom state (PASS) and substantial clinical benefit (SCB) thresholds are used.
Researchers studied patients enrolled in a database who underwent 1,581 aTSAs and 2,061 rTSAs and had 2-year minimum follow-up. Surgeries were performed by 13 surgeons using the Equinoxe (Exactech) prosthesis platform. Researchers assessed all follow-up visits for the two cohorts beyond the 2-year follow-up for MCID, PASS and SCB thresholds, as well as VAS for pain, global shoulder function, simple shoulder test, Constant score, American Shoulder and Elbow Surgeons score, University of California, Los Angeles score, shoulder pain and disability index score and shoulder arthroplasty smart score.
Range of motion, diagnosis
Researchers factored in active range of motion measures — active abduction, active forward flexion, internal rotation score and active external rotation — which were calculated for patients in both cohorts with osteoarthritis, rheumatoid arthritis, rotator cuff tear and cuff tear arthropathy using an anchor-based method.
Calculations of MCID, PASS and SCB, according to the two types of arthroplasty and various diagnoses, showed thresholds were generally higher for aTSA than for rTSA.
“The results of this study demonstrate differences in MCID, SCB and PASS thresholds for PROMs and motion measures when stratified by prosthesis type and diagnosis. This strengthens the concept that MCID, SCB and PASS values cannot be conflated within and between studies when the populations might be heterogenous in patient attributes, diagnoses or prosthesis type,” Elwell and colleagues wrote in the abstract.
Regarding trends for aTSA vs. rTSA based on diagnosis, Elwell said, “We can see the overall aTSA cohort had higher thresholds for improvement and postop scores than the overall rTSA cohort. So, this is probably a function of rTSA cohorts being less functional before surgery and not expecting that functional restoration.”
Regarding VAS pain, however, “those thresholds are similar between the cohorts, so a goal across all patients is likely alleviate the patient of pain,” she said.
Trends for aTSA vs rTSA
Elwell, who is a product development engineer for Exactech, discussed trends specific to the two cohorts.
The similar trends for aTSA were “the rotator cuff tear cohort had higher MCID and SCB thresholds for range of motion, but lower for pain improvement compared to other cohorts. Perhaps this cohort is seeking functional improvement, but not necessarily pain alleviation,” she said, noting these patients may have less pain preoperatively than the OA cohort.
Within the prosthesis cohorts, these thresholds also varied by diagnosis, according to the abstract.
For example, for aTSA, “the rheumatoid arthritis cohort had consistently lower thresholds for range of motion, but similar for the PROMs, which considered subjective range of motion, pain and strength questions,” Elwell said.
As an example of thresholds that varied by diagnosis in the rTSA results was the cuff tear arthropathy cohort, which “had lower thresholds for range of motion and PROMs vs. the OA diagnosis cohort,” she said.
Such variation could have occurred because of lower preoperative function and lower expectations for functional restoration, according to Elwell. “But this is also supported, similarly to the overall cohorts, where VAS pain had similar thresholds across all diagnoses with the exception of RA. That actually had higher thresholds for pain, and this may be because of their increased preoperative pain and less expectation for restoration of function from these patients as opposed to alleviation of pain.”
Manage patient expectation
“This is one of the first studies to determine shoulder-specific MCID, SCB and PASS thresholds based on prosthesis type and diagnoses,” Elwell said. These results can help clinicians better manage patient expectations with regard to TSA, as well as assist with evaluation of patient outcomes at various stages of care. The results may also be useful in assessing “differences in treatment options to determine if they may be clinically relevant for a patient or not,” she said.
A study limitation was the results may not be applicable to all patients who undergo primary TSA because only one prosthesis system was included, Elwell said. Furthermore, the thresholds may be sensitive to the anchor questions used to determine the questions, she said.
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Colsanti C, et al. Paper 205. Presented at: Orthopaedic Research Society Annual Meeting. Feb. 4-8, 2022; Tampa, Fla.
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