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Abstract & Commentary
Synopsis: Thirty-seven patients with calcific tendinitis were treated successfully with shock wave therapy. Shock wave therapy is a safe, effective, and noninvasive treatment of calcific tendinitis of the shoulder.
Source: Wang CJ, et al. Shock wave therapy for calcific tendonitis of the shoulder. A prospective clinical study with 2-year follow-up. Am J Sports Med. 2003;31(3):425-430.
The inclusion criteria for this study were patients with shoulder pain attributable to calcific tendinitis who had failed to respond to nonoperative treatment. Thirty-nine shoulders were involved in the study group and 6 in the control group. Groups were not randomized; only patients who agreed to participate as control subjects were involved in this group. In the study group, the mean follow-up was 2 years, while it was only 8.6 months in the control group.
For the study group, any other treatment was stopped 2 weeks before the beginning of the shock wave treatment. Local anesthesia was injected in the subacomial space before the procedure. Repeated application at 30-60 days was provided if necessary. In the control group, sham treatment was performed with a dummy electrode. Patients were sent home the same day with an ice pack and painkiller; no anti-inflammatory drugs were prescribed.
The evaluations were performed over 2 years by an independent observer blinded to whether patients were in the study or control group. The evaluation was done using the Constant score. In the control group, all 6 patients decided to seek alternative methods of treatment including surgery after a mean of 6 months of follow-up. For the study group, the improvement was statistically significant regarding pain, activity, and motion score. Twenty shoulders were complaint-free, 10 were significantly better, 1 was slightly better, and 2 were unchanged. There were no systemic or local complications. Radiographic assessment demonstrated that the elimination of calcium deposits was complete in 19 cases, partial in 5, and unchanged in 9. Studies have shown that results of both nonoperative and surgical treatment may be inconsistent and unpredictable. When compared with surgery, shock wave therapy is safe, cost-effective, and without the risk and complications entailed by surgery.
Comment by J.P. Warner, MD, and Philippe Clavert, MD
Many treatments of calcific tendinitis of the shoulder are available. This paper shows a new treatment with good results. Both the pathogenesis and method of improvement of calcific tendinitis of the shoulder remain unclear. The hypothesis is that the calcium deposit is eliminated through a molecular mechanism of absorption, which is induced by the improvement of the local circulation at the bone-tendon junction after shock wave therapy. That is why the effects of shock wave therapy appear to be cumulative and time-dependant. The radiographic results of this study confirm that there is a poor correlation between the radiographic aspects of the calcium deposit and the clinical outcome. Some patients remain asymptomatic with persistent calcium deposits after a long period of time.
On the other hand, it is hard to state that the results of shock wave therapy for calcific tendinitis are highly significant because there is a disproportion in the number of patients in the 2 groups. Furthermore, there is no randomization to select patients for the study and the control group. Patients belonged to the control group only if they agreed to it; they may not be fully objective in their follow-up evaluation. Furthermore, Wang and colleagues highlight the fact that the patients’ review was done by a blind and independent observer. Since the patient knows in which group he belongs, he may influence the observer.
Lastly, the average time of follow-up in the 2 groups is not the same. We know that pain related to calcium deposits varies over time and is not related to the radiographic aspect of the deposit. A longer follow-up of the control group may have shown improvement with the conservative treatment. Moreover, the conservative treatment used for the control group is not clearly described in the manuscript. We may wonder if this treatment was appropriate and if the patients were compliant.
Dr. Warner, Associate Professor of Orthopaedics,Harvard Medical School, Boston, MA, is Associate Editor of Sports Medicine Reports. Dr. Clavert is a Fellow in Shoulder Surgery at Harvard University.