Postoperative ossifications of the shoulder. Incidence and clinical impact.

Periarticular ossifications of the shoulder after surgery have been described since the beginning of the century. Risk factors and the clinical impact of heterotopic bone formation have been discussed controversially. After open surgery on the shoulder, 131 patients (rotator cuff repair n = 106, acromioplasty n = 25) were included in a retrospective study if pre- and postoperative X-rays were available. The age of the 90 men and 41 women averaged 51 years (range 29-67 years). The minimum follow-up was 2 years. Also, 108 patients were interviewed by questionnaire to estimate the subjective outcome of the procedure (5 patients were reported dead). A clinical examination was carried out on 86 patients using the Constant score for evaluation of the objective outcome. Heterotopic ossifications were found in 35 cases (26.7%), 28 of them after rotator cuff reconstruction and 7 after acromioplasty. A good to excellent result was reported by 89% (n = 65) of the patients without and by 80% (n = 28) of the patients with ossifications. The Constant score averaged 69 points and 74 points (n = 60), respectively. A significant difference between the two collectives could not be calculated. As significant risk factors for the formation of heterotopic bone, the existence of osteoarthritis and the duration and complexity of the procedure could be cited. The appearance of periarticular ossifications after surgery of the shoulder seems to be of minor clinical impact. Severe cases with major functional deficits should and can be prevented by a fast and atraumatic operation technique.