The smallest worthwhile effect on pain and function for rotator cuff repair surgery: a benefit-harm trade-off study

Background: The smallest worthwhile effect (SWE) is the minimum benefit required in addition to that from a comparator, for an intervention to be considered worthwhile by patients. We aimed to estimate the SWE for rotator cuff repair (with decompression and debridement) compared to either decompression and debridement alone or to non-surgical treatment for people with atraumatic shoulder pain. Methods: Benefit-harm trade-off study. We recruited English speaking adults aged 45-75 years with shoulder pain of intensity ≥4 (on a 0-10 scale) for ≥6 months to our online survey through paid advertising on Facebook. Participants must have sought care in the past 6-months and could not have had recent shoulder surgery or significant recent shoulder trauma. Participants were explained three treatments: rotator cuff repair (with subacromial decompression and debridement), subacromial decompression and debridement alone and non-surgical treatment. Participants completed the benefit-harm trade-off survey to determine the SWE of improvements in pain and function for rotator cuff repair compared to the other treatments and again after one week to assess reliability. We used univariable linear regression to estimate associations between baseline characteristics and SWE. Results: We recruited 56 participants. The mean (standard deviation) age was 58.4 (6.7) years and 39 (70%) were female. For rotator cuff repair to be worthwhile compared to decompression and debridement alone participants needed to see at least a median 40% (interquartile range (IQR) 20-62.5) between-group improvement in pain and function. Compared to non-surgical treatment, the SWE was a median 40% (IQR 30-60). On the Western Ontario Rotator Cuff (WORC) Index the SWE values equate to a between-group improvement of 28/100 points (533/2100 on the raw WORC score). Female sex was associated with larger SWEs for both comparisons. Reliability analyses were underpowered, 25/56(45%) provided follow-up data; the intraclass correlation coefficient estimates ranged from 0.60-0.77. Conclusions: This SWE indicates the benefit required by people with shoulder pain to consider the costs and risks of surgical rotator cuff repair worthwhile is larger than previously estimated minimum clinically important differences (13.5-28/100 on the WORC Index). This SWE may be used to inform the design or interpret the findings of trials of these comparisons.