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  • Study: Popular Shoulder Procedure Provides No Relevant Clinical Benefit Over 'Placebo Surgery'

    Researchers in Finland have once again conducted a study that used "placebo surgery" to conclude that another frequently used arthroscopic procedure likely has little to no benefit: this time around, it was subacromial decompression surgery for shoulder impingement that was found to be no better than diagnostic arthroscopy alone. The procedure was also compared with physical therapy alone, but researchers are uncertain about the reliability of the results.

    The study, published in BMJ, compared shoulder pain at rest and with arm activity among 122 participants, aged 35 to 65, who presented with shoulder impingement occurring for at least 3 months and unresponsive to "conventional treatment." Participants agreed to undergo arthroscopic surgery and understood that they may be receiving either simple diagnostic arthroscopy with no other surgical procedure, or arthroscopic subacromial decompression surgery (ASD), a procedure that involves smoothing the undersurface of the acromion in hopes of easing the passage of the rotator cuff tendon through the subacromial space. Authors characterize ASD as "one of the most frequently performed orthopaedic procedures in the world."

    Researchers were careful to avoid introducing any hints as to who received which procedure, even going so far as seeing to it that the surgeons themselves didn't know which procedure they were doing until after the initial diagnostic arthroscopy and a nurse opened a sealed envelope telling the surgeon whether to proceed with ASD or end the procedure. Additionally, patients who did not receive ASD were kept in the surgical room for the time it would've taken to conduct the procedure, and no other facility staff were told which patients received which kind of surgery.

    Both groups received the same postoperative care—a single visit to a physical therapist (PT) "for guidance and instructions for home exercises." The PT was also in the dark about whether the participant had received ASD or placebo surgery.

    After 24 months, the researchers measured participants' shoulder pain at rest and during arm activity by use of a 0-100 visual analogue pain scale. Secondary outcomes were related to shoulder function, assessed through a Constant-Murley score and the 15D, a health-related quality of life measure. All 24-month assessments were compared with those captured at baseline and 3-months, 6-months, and 12-months postsurgery.

    Researchers noted "marked improvement" among all the participants, but that's what was so revealing: it didn't seem to matter whether the patient had received ASD or the placebo. The results were true for both pain and function assessments.

    Authors of the study believe the findings are made stronger by what they describe as the "stringent eligibility criteria" they used to select only participants "most likely to benefit from ASD."

    "Classically, stringent eligibility criteria are considered to decrease the validity of a study," authors write. "Although our patient population was indeed highly selected…we think that the use of stringent eligibility criteria paradoxically increases the generalizability of our findings. When ASD was proven futile under this best case scenario, there is no reason to assume that it would work better under less optimal circumstances or in a more heterogeneous population."

    Researchers also compared the surgery groups with a third group of participants who participated in 15 sessions of physical therapy. While they found no significant differences in outcomes at 24 months, authors caution against reading too much into those results, primarily because participants in the exercise group weren't weeded out as thoroughly as those in the surgery group beforehand. "Thus the ASD versus exercise therapy comparison is likely to be biased in favor of ASD owing to systematic removal of patients with likely poorer prognosis [in the ASD group]," authors write.

    The study's approach is similar to a 2014 research project, also from Finland, that looked into arthroscopic surgery for meniscal tears. Like the shoulder study, the meniscal study involved the use of placebo surgery and found a similar lack of difference in outcomes between those who received the sham meniscal surgery and those who received the real thing. Four of the authors of the shoulder study are listed as coauthors of the meniscus research paper.

    As for the shoulder study, authors were nothing if not direct in their assessment of the results.

    "The results of this study…show that [ASD] provides no clinically relevant benefit over diagnostic arthroscopy in patients with shoulder impingement syndrome," authors write. "The findings do not support the current practice of performing subacromial decompression in patients with shoulder impingement syndrome."

    Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.