Occult midtarsal subluxation.

Of 14 patients with navicular tuberosity avulsion, seven had damage to the anterior process of the calcaneum at the calcaneocuboid joint--possibly the result of an occult subluxation of the midtarsal joint. These patients were all middle-aged women who had slipped or fallen a short distance. They were unable to bear full weight because of pain on the medial and lateral aspects of the foot. The associated midtarsal injury was initially missed in five of seven patients because of failure to interpret the radiographic appearance. All seven patients had prolonged symptoms, and three had persistent but not disabling pain at least three years after injury. Degenerative arthritis had developed in the calcaneocuboid joint in four of the five patients at follow-up examinations. Patients with occult subluxation of the midtarsal joint should be managed initially by a period of non-weight-bearing followed by application of a walking cast. The need for early surgical treatment is open to question.