[Coxarthrosis due to contusion].

Can a contusion cause coxarthrosis in the absence of both fracture and dislocation? Yes. To demonstrate this the authors report 6 cases that fulfil the following conditions: (1) Simple but violent contusion affecting the greater trochanter or the knee (dashboard accident) or a forced movement, such as in doing the splits; (2) immediate or slightly delayed pain, generally of short duration (a few weeks); (3) absence of coxarthrogenic malformations and absence of pre-existing signs of a pathological hip condition; (4) progressive coxarthrosis on the side of the contusion; (5) chronological relation between the development of the coxarthrosis images and the date of the contusion; (6) subjects less than 35 years of age, in order to eliminate cases with latent primary pre-coxarthrosis. The average age of the six patients at the start of the coxarthrosis was 24.7 years (range: 13 to 33 years); there were four men and two women. In five of the six cases a violent contusion in the trochanter region was involved as a result of a fall on a hard surface or a traffic accident. In one case a forced movement on landing from a jump was involved. Evolution in three periods is usual: the hip is painful either immediately or after a few weeks (particularly on rising after a period in bed for multiple injuries). This post-traumatic pain lasts from ten days to one month, rarely longer. It is followed by a period free of pain that may last from five months to ten years (average: five years). Subsequently there is pain every day and the onset of the limp associated with coxarthrosis. Radiographically the reduction of the joint space and/or the osteophytosis appears after three months to two years (average: one year). However, there may not be any pain associated with these lesions for a long time. The authors propose that the first five conditions enumerated above represent the essential medico-legal conditions of coxarthrosis by contusion. The restriction as regards age (No 6) was introduced only to show clearly the existence of post-contusive coxarthrosis. However, even if one or more of the medico-legal conditions are not fulfilled the imputability may still be valid. Some such cases are discussed.