Extra-articular fibrous ankylosis of the mandible after zygomatic fracture.

Zygomatico-coronoid fibrous ankylosis of the mandible is a complication which rarely occurs if fractures of the middle third of the facial skeleton have been adequately treated. 379 zygomatic fractures in hospitalized patients were treated at the Department of Jaw Surgery of the Surgical Hospital in Helsinki between 1969 and 1975. 36 cases were characterized by convalescence being complicated by significant restriction of jaw opening. 25 patients were successfully treated by physiotherapy and 6 other by a forced opening of the jaws under general anaesthesia. In the remaining 5 cases 91.3% of the fractures) the clinically verified fibrous extra-articular ankylosis was resistant to the above mentioned conservative methods and was treated instead by intraoral coronoidectomy, supplemented in one instance by a partial myotomy of the affected masseter muscle. The importance of prophylactic physiotherapy is stressed and applies to both the post-accident and the post-corrective-operation period.