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Is Arthroscopic Sub-Acromial Decompression (ASAD) More Effective Than Arthroscopy Only (AO) for Shoulder Pain

Csaw can shoulder arthroscopy work

Can Shoulder Arthroscopy Work?                                                                      

The CSAW Trial (funded by Arthritis Research UK) is a multi-centre randomised controlled trial (RCT). The primary objective of the study is to determine whether the commonly used arthroscopic sub-acromial decompression surgery is an effective treatment for patients with sub-acromial shoulder pain (impingement). The study comparisons include surgical and non-surgical approaches to treating sub-acromial shoulder pain. The Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS) coordinates the study via the Surgical Intervention Trials Unit (SITU) in collaboration with the co-chief investigators Professors David Beard and Andrew Carr.


This study aims to compare surgical treatment for sub-acromial shoulder pain (ASAD) against a non-operative arm, Active Monitoring with Specialist Reassessment (AMSR). In addition, both ASAD surgery and AMSR will be separately compared to investigational shoulder arthroscopy (AO) to delineate the mechanism for any benefit.

The Primary Outcome Measure is the Oxford Shoulder Score (OSS) at 6 months.



Painful shoulders pose a significant socio-economic burden with sub-acromial shoulder pain being the most frequent cause of shoulder problems in the general population. It is known that a high proportion of patients with sub-acromial shoulder pain will respond well to conservative treatment alone. For patients who have symptoms resistant to conservative measures arthroscopic sub-acromial decompression surgery (ASAD) is the most commonly used surgical intervention.

ASAD has been used in the treatment of sub-acromial shoulder pain for over 35 years and the number of procedures performed has significantly increased over time. A fact made remarkable by the absence of any compelling or concrete evidence in support of the procedure. Various studies have been carried out  but there has not been a randomised controlled trial (RCT) performed on patients with sub-acromial shoulder pain that shows ASAD to be more effective than simply inserting the arthroscope or doing nothing at all. The NHS Database of Uncertainties about the Effects of Treatment (DUETs) confirms this lack of evidence. They highlight the low level of evidence available and the high susceptibility of bias which exists in some publications on the topic. Therefore, we remain ignorant to the mode of action for any potential therapeutic effect. CSAW aims to test all three management options satisfactorily.


CSAW Patient Information Sheet

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