Surgery for Shoulder Impingement

Is surgery for shoulder impingement of help to patients? I have no doubt that it helps some patients, but what is the evidence in regards to surgery versus conservative rehabilitation?

The following literature caught my eye recently:

Ketola et al (2013)

• A five-year randomised controlled trial examining the effectiveness of arthroscopic acromioplasty in the treatment of stage II shoulder impingement syndrome.
• A total of 140 patients were randomly divided into two groups: 1) supervised exercise programme (n = 70, exercise group); and 2) arthroscopic acromioplasty followed by a similar exercise programme (n = 70, combined treatment group).
• Results:
• At the five-year assessment a total of 109 patients were examined (52 in the exercise group and 57 in the combined treatment group). There was a significant decrease in mean self-reported pain on the VAS between baseline and the five-year follow-up in both the exercise group (from 6.5 (1 to 10) to 2.2 (0 to 8); p < 0.001) and the combined treatment group (from 6.4 (2 to 10) to 1.9 (0 to 8); p < 0.001). The same trend was seen in the secondary outcome measures (disability, working ability, pain at night, Shoulder Disability Questionnaire and reported painful days).
• An intention-to-treat analysis showed statistically significant improvements in both groups at five years compared with baseline. Further, improvement continued between the two and five-year timepoints.
• No statistically significant differences were found in the patient-centred primary and secondary parameters between the two treatment groups.
• Conclusions: 
• Differences in the patient-centred primary and secondary parameters between the two treatment groups were not statistically significant, suggesting that acromioplasty is not cost-effective.
• Structured exercise treatment seems to be the treatment of choice for shoulder impingement syndrome.

So the conclusions I reach from the above are:

1. Surgery for shoulder impingement can be of assistance, but;

2. Given that there is no great difference in outcomes between surgical versus exercise therapy for patients then surely an extensive period of conservative treatment should be trialled before acromioplasty is undertaken.

Even if we were to be contemplating sending them off to surgery it is important to be mindful for the presence of central sensitisation:

Gwilym et al (2011):

• Investigated the evidence for augmented pain transmission (central sensitisation) in patients with impingement, and the relationship between pre-operative central sensitisation and the outcomes following arthroscopic subacromial decompression.
• 17 patients with unilateral impingement of the shoulder and 17 age and gender matched controls, all of whom underwent quantitative sensory testing to detect thresholds for mechanical stimuli, distinctions between sharp and blunt punctate stimuli, and heat pain.
• Additionally Oxford shoulder scores to assess pain and function, and PainDETECT questionnaires to identify ‘neuropathic’ and referred symptoms were completed. Patients completed these questionnaires pre-operatively and three months post-operatively.
• A significant proportion of patients awaiting subacromial decompression had referred pain radiating down the arm and had significant hyperalgesia to punctate stimulus of the skin compared with controls (unpaired t-test, p < 0.0001). These are felt to represent peripheral manifestations of augmented central pain processing (central sensitisation).
• Results:
• The presence of either hyperalgesia or referred pain pre-operatively resulted in a significantly worse outcome from decompression three months after surgery (unpaired t-test, p = 0.04 and p = 0.005, respectively).
• These observations confirm the presence of central sensitisation in a proportion of patients with shoulder pain associated with impingement.
• If patients had relatively high levels of central sensitisation pre-operatively, as indicated by higher levels of punctate hyperalgesia and/or referred pain, the outcome three months after subacromial decompression was significantly worse.

This finding doesn’t really surprise me given that I would suggest that patients generally that have neuropathic pain and/or central sensitisation don’t seem to do well with most treatments. So once again, central sensitisation and/or neuropathic pain would appear to be a negative prognostic indicator for surgery. That doesn’t mean that you would avoid surgery with a patient demonstrating that type of presentation, but I certainly think it shouldn’t be high on the list of treatment priorities. Treatment to attempt to improve the neuropathic/central sensitisation symptoms first should be the first option. Surgery should once again be the last resort, as it probably isn’t going to help, but we shouldn’t also rule a line through it and never have patients undertake it.

My take home message:

Acromioplasty for shoulder impingement should most likely be used as a last resort option in shoulder impingement, regardless of the presence, or not, of central sensitisation/neuropathic pain.

But we also shouldn’t take the above as a message to “rule a line” through surgery for shoulder impingement and completely disregard it as an option.

I hope you have enjoyed reading this.

References:

Gwilym SE, Oag HC, Tracey I, Carr AJ. Evidence that central sensitisation is present in patients with shoulder impingement syndrome and influences the outcome after surgery. J Bone Joint Surg Br. 2011 Apr;93(4):498-502.

Ketola S, Lehtinen J, Rousi T, Nissinen M, Huhtala H, Konttinen YT, Arnala I. No evidence of long-term benefits of arthroscopicacromioplasty in the treatment of shoulder impingement syndrome: Five-year results of a randomised controlled trial. Bone Joint Res. 2013 Jul 1;2(7):132-9.