The pathogenesis of the late post-traumatic rupture of the extensor pollicis longus tendon has never been satisfactorily explained. In the present series of fifty-nine ruptures two were partial, making possible an exact localization of the rupture. Microangiographic studies performed on amputated arms showed that this part of the tendon was poorly vascularized. Our study confirms earlier observations that ruptures most commonly occur after undisplaced fractures. It is suggested that increased pressure within the non-ruptured tendon sheath jeopardizes the blood flow in the already poorly vascularized parts of the tendon, leading to degeneration and rupture, usually within eight weeks. An haematoma inside the sheath interfering with the production of synovial fluid, could deprive the tendon of an alternative nutrition via diffusional pathways.

Polyglactin 910, a resorbable synthetic material, was used as a mesh-tube to bridge defects (7 to 9 mm in length) in a sectioned rabbit tibial nerve. After absorption of the mesh a new nerve sheath was formed which enclosed numerous minute fascicles of regenerating axons. The polyglactin tube influenced the direction taken by the regenerating axons and guided them into the distal segment. The tube also reduced the formation of neuromas and the growth of scar tissue from surrounding structures.

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In an experimental study the cartilaginous protential of the rabbit ear perichondrium has been compared with that of the rib in vivo and in vitro. Perichondrium was transferred as free autologous grafts to the subcutaneous tissue on the scalp and as loose bodies into the knee joint. The presence of cartilage in the grafts was examined after six weeks. In vitro explants of rabbit perichondrium from the ear and the rib were maintained in an organ culture system. The presence of cartilage was analyzed after one to three weeks. Rabbit perichondrium from the rib appeared to have a greater cartilaginous potential than that from the ear both in vivo and in vitro. Chondrogenesis in perichondrium was demonstrated in vitro.

An experimental study in adult rabbits has been performed to find out whether the cartilage forming capacity of the perichondrium could be utilized in reconstruction of articular cartilage. The normal articular cartilage of the glenoid surface of the humero-scapular joint was completely removed. Auricular perichondrium was grafted to cover the exposed bony surface with the active chondrogenic layer of the perichondrial graft facing the joint cavity. The joint was not immobilized but the operated limb was amputated at wrist level to avoid weight bearing. The animals were sacrificed at different time intervals ranging from 1 to 17 weeks. In 12 out of 14 grafted rabbits regeneration of cartilage occurred. In 6 of 10 control cases where no perichondrium was grafted to cover the resected surface no cartilage was found. In the other 4, only small areas of mature cartilage were seen, probably remnants of the original articular cartilage.

In twenty-four patients with intolerance to cold after partial or complete finger amputations, lower skin temperature together with cold and vibration allodynia (allodynia = pain due to a non-noxious stimulus to neural skin) were found in the cold intolerant area compared with the corresponding area in the uninjured hand. When treated with regional intravenous guanethidine block nine patients became free from symptoms for up to twelve weeks, which is longer than would be expected from the duration of the known pharmacological effects of guanethidine. The patients had several features in common with reflex sympathetic dystrophies, and we suggest that neurogenic rather than vascular disturbances are mainly involved in the post-traumatic cold intolerance syndrome.

Pain, impaired mobility and weakness in the wrist are common complications after fractures of the lower end of the radius. When these symptoms persist, resection of the distal end of the ulna has been the surgical treatment of choice. 24 patients who had undergone this procedure were reviewed. 50% stated they were not improved by the operation. Of 11 patients with degenerative changes in the distal radio-ulnar joint on preoperative X-ray, 8 stated they were helped by the operation, while of 13 patients without any signs of arthrosis in the distal radio-ulnar joint, only 4 experienced relief of their discomfort. A more discriminating approach to the treatment of the sequelae of fractures to the lower end of the radius is required. Resection of the distal end of the ulna is probably only indicated when the distal radio-ulnar joint shows sings of arthrosis.

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