AO-wrist arthrodesis: with and without arthrodesis of the third carpometacarpal joint.

The incorporation of the third carpometacarpal joint (CMCJ-3) during wrist arthrodesis is controversial. This retrospective study of 146 consecutive wrist arthrodeses with AO plate fixation specifically addresses this question. In 79 wrist arthrodeses the CMCJ-3 was also arthrodesed, and in 67 the CMCJ-3 was simply bridged. Problems relating specifically to the CMCJ-3 could not be analyzed clearly with the plate in situ. Therefore after plate removal only 81 wrists were evaluated with respect to the CMCJ-3. Of 47 wrists that had CMCJ-3 arthrodesis and plate removal, 20 developed a nonunion. Eleven of these were painful and further surgical treatment was required. In contrast, of 34 wrists with the CMCJ-3 bridged all but one remained free of symptoms after the plate had been removed. We conclude that the CMCJ-3 must not be included in the arthrodesis when performing an AO-wrist arthrodesis.

Heterotopic ossification of peripheral nerve ("neuritis ossificans"): report of two cases.

OBJECTIVE AND IMPORTANCE: Heterotopic ossification ("neuritis ossificans") is among the least frequently encountered reactive lesions in peripheral nerves. Only two cases have been described previously, one in the median nerve of a 34-year-old man, and the other in the ulnar nerve of an adult woman. The architecture of this lesion is distinctly zonal. Consisting of a central fibroblastic core, an intervening zone of osteoid production, and a peripheral layer of ossification, the pattern is remarkably similar to that of myositis ossificans. This similarity and the occurrence of the process in superficial nerves have led to speculation that trauma plays a role in its pathogenesis; this hypothesis remains unproved. We describe two additional cases of neuritis ossificans. CLINICAL PRESENTATION: One patient, a 41-year-old man, experienced pain and numbness in the left leg for several months but had no history of local trauma. A mass was detected in the saphenous nerve. The second patient, a 16-year-old boy, noted subacute onset of pain in the popliteal fossa and decreased sensation in the distribution of the lateral sural cutaneous nerve. A mass was found within the tibial nerve at the knee level. INTERVENTION: In each patient, resection of the mass required sacrifice of a segment of the nerve. CONCLUSION: In each patient, the mass was composed of fibrovascular tissue with osteoid and bone deposition arranged in a zonal pattern. The ossifying process was intraneural but encased rather than directly involving nerve fascicles. These exceptionally intact examples of neuritis ossificans underscore its resemblance to myositis ossificans. Nerve-sparing resection of such masses is not always possible.