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Upper Limb: H. E. Henkus, P. B. de Witte, R. G. H. H. Nelissen, R. Brand, and E. R. A. van Arkel Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome: A PROSPECTIVE RANDOMISED STUDY J Bone Joint Surg Br 2009; 91-B: 504-510 [Abstract] [Full text] [PDF]

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Author's reply

Hans-Erik Henkus   (9 June 2009)

Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome

Tom M Lawrence, Shantanu Shahane   (6 May 2009)

Author's reply 9 June 2009
Hans-Erik Henkus, Orth.surgeon Haga Hospital The Hague, The Netherlands Send letter to journal: Re: Author's reply h.henkus{at}hagaziekenhuis.nl Hans-Erik Henkus	Sir, I would like to thank Drs Lawrence and Shahane for their letter in response to our paper. In this study, unfortunately, no formal power analysis was performed in advance and this is a concern when interpreting the results. However, although a priori power analysis is obviously required to assess the feasibility of any study, the post-hoc 'power' of the study is completely and correctly reflected in the confidence interval widths. We have formulated the statements in the paper in such a way that all reasoning has been built upon the confidence limits rather than on the statistical significance, avoiding the erroneous reasoning that might infer absence-of-effect from statistical insignificance. If the confidence intervals had encompassed both clinically relevant and clinically irrelevant effect sizes, the study would clearly have been underpowered. However, we believe this is not the case in this study. In both groups a complete debridement of the subacromial bursa was performed using a motorised shaver and an electrocautery probe. When randomised for a bursectomy no further treatment was performed. The bony spur and the coraco-acromial ligament was left intact since this may alter the coraco-acromial arch. In patients randomised for acromioplasty, a flat undersurface of the acromion was created using a motorised burr through a lateral and posterior portal. To achieve this the coraco-acromial ligament was partly resected in most of the cases. Two patients having a bursectomy were not improved in their clinical scores after one year of follow-up. Since a bursectomy is not the standard operative procedure for patients with the impingement syndrome a formal acromioplasty was performed. One patient did not improve after the second operation in all clinical scores. The second patient showed no improvement in range of motion and strength, as recorded in the Constant score, but described less pain and a better function in the VAS scores. Unfortunately we did not look at the recovery pathways of the two groups. We did, however, see a faster recovery in patients with a bursectomy in the immediate post-operative phase. H.E. Henkus, Orthopaedic Surgeon, Haga Hospital, The Hague, The Netherlands.
Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome 6 May 2009
Tom M Lawrence, SpR Trauma and Orthopaedics Chersterfield Royal Hospital, Shantanu Shahane Send letter to journal: Re: Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome tomlawrence75{at}hotmail.com Tom M Lawrence, et al.	Sir, We read with interest the article by Henkus et al in the April 2009 issue entitled “Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome: a prospective randomised study”1. The aetiology of impingement remains controversial, as does the concept of performing acromioplasty. For the most part acromioplasty continues to be an integral step in subacromial decompression surgery. This study attempts to address these important issues and the authors conclude that there are no significant differences in clinical outcome between bursectomy alone and acromioplasty. On this basis they suggest that subacromial impingement is an intrinsic degenerative condition rather than an extrinsic mechanical disorder. The reader would logically conclude that when operating on patients suffering from subacromial impingement, bursectomy alone will suffice and that acromioplasty is unnecessary. If we were to accept this conclusion then the healthcare implications could be massive: reduced surgical time, fewer complications, faster post-operative recovery and earlier return to work. However, we have major concerns regarding the small size and lack of power in the study. Are the authors certain that they have correctly accepted the null hypothesis and not made a type II statistical error? The acromioplasty group are seen to perform better in all outcome measures, suggesting that if the study were sufficiently powered, clinical outcome would favour this group. We feel that the authors do not adequately describe the surgical procedures. It is imperative to know whether the bursectomy procedure involved any form of resection of the coraco-acromial ligament, which in itself would decompress the subacromial space. The acromioplasty group also were treated with debridement of the subacromial bursa – did this differ from the bursectomy alone? Furthermore, we note that two patients treated by bursectomy alone needed a second procedure, which was an acromioplasty – did these patients improve as a result of the acromioplasty and if so, how do the authors account for this? Finally, clinical assessments were made at three monthly intervals although the data presented relates only to final follow-up. It would be interesting to know whether the bursectomy group recovered faster than those undergoing acromioplasty. T.M. Lawrence, SpR Trauma and Orthopaedics, S. Shahane, Chesterfield Royal Hospital, Chesterfield, Derbyshire, UK. 1. Henkus HE, de Witte PB, Nelissen RGHH, Brand R, van Arkel ERA. Bursectomy compared with acromioplasty in the management of subacromial impingement syndrome: a prospective randomised study. J Bone Joint Surg [Br] 2009;91-B:504-510.