Physiotherapy or corticosteroid injection for shoulder pain?

1 report the results of a randomised clinical trial evaluating the effectiveness of physiotherapy and corticosteroid injection for patients with unilateral shoulder pain. Shoulder pain is a common complaint; estimates of the annual incidence in general practice vary from 6.6 to 25 cases per 1000 patients. 2–4 Most patients are treated in primary care. If treatment with analgesics or non-steroidal anti-inflammatory drugs (NSAIDs) is not successful, patients with persistent symptoms are often referred for physiotherapy or treated with local infiltration of a corticosteroid. 4 Until recently, evidence on the effectiveness of these interventions was scarce, particularly for primary care patients. Over the past few years two randomised trials have been published that directly compared the effects of physiotherapy with cortico-steroid injections. 5 6 Both trials were carried out in Dutch general practice. The trial by Hay et al adds important and relevant information to this existing evidence. The trial is characterised by a thorough design, enrolled a relatively large number of patients, used relevant outcome measures, and achieved a nearly complete six months' follow up of participants. When examining the results of these three primary care trials, three issues arise for discussion. Firstly, the short term findings are rather different , with the Dutch trials clearly showing better effects of corticosteroid injections , whereas the English trial reports similar outcomes for the two interventions. Secondly, all three trials show minor and non-significant differences at long term follow up. 1 6 7 Thirdly, the somewhat ambiguous overall evidence may leave substantial room for considering patient preferences and expectations when applying the results in clinical practice. Inconsistent short term results: differences in study group, content of treatment, or outcome measures? Figure 1a shows the self reported change of symptoms at 5–7 weeks of follow up for the three trials. As mentioned above, the short term differences strongly favour injections in the Dutch trials, whereas small, non-significant differences in the opposite direction are reported for the English trial. This heterogeneity in findings clearly exceeds random variation, which is confirmed by statistically testing for homogeneity (χ 2 = 32.4, p<0.00001). It is of interest to assess whether this heterogeneity can be explained by differences in clinically relevant factors, such as characteristics of the patient group or content of treatment. 8 9 The trial by van der Windt et al specifically selected patients with restricted range of motion (painful and stiff shoulder), and reported slightly …