The natural history of suspected scaphoid fractures.

Clinically suspected scaphoid fractures are common injuries. The authors prospectively followed up, by serial radiography and bone scanning, 23 patients who had a history of trauma to the carpus and associated localized tenderness to the anatomic "snuff box": in 15 patients the radiographs and bone scans were negative; in 5 the radiograph was equivocal and the bone scan positive. The authors concluded that patients with clinically suspected scaphoid fractures and negative radiographs can be treated symptomatically without immobilization in a cast. Patients with equivocal radiographs should be assumed to have a fractured scaphoid and treated accordingly.

The effect of continuous passive motion on knee ligament reconstruction with carbon fibre. An experimental investigation.

Our purpose was to determine whether continuous passive motion enhanced the quality of knee ligament reconstruction using carbon fibre. In 46 rabbits the medial collateral ligaments were excised and replaced with carbon fibre prostheses. The animals were treated postoperatively by either continuous passive motion, cast immobilisation or cage activity, termed intermittent active motion. At six weeks, the ligaments were compared histologically and biomechanically with normal (control) medial collateral ligaments and with sham-operated controls. The ligaments treated with continuous passive motion were superior to those in the other two treatment groups. There were no ligament failures in any of the groups. This study suggests that continuous passive motion, initiated immediately postoperatively, enhances the biomechanical properties of carbon fibre ligament replacement of the medial collateral ligament while preventing the harmful effects of joint immobilisation.

Periosteal neochondrogenesis for biologically resurfacing joints: its cellular origin.

The purpose of this study was to determine if the hyaline-like cartilage produced in major full-thickness defects of a joint surface, treated by a free periosteal graft and subjected to continuous passive motion (CPM), originated exclusively from the progenitor cells of the cambium of the graft. Free periosteal grafts were raised from the tibia of both hind legs of eight male New Zealand rabbits and transplanted into full-thickness defects across the entire width of the patellar groove of 15 female rabbits. Postoperatively, CPM was instituted and the animals were sacrificed after 3 weeks. Cells from the regenerated tissue were grown from tissue explants and their karyotypes determined. In 33% of the rabbits, all cells contained a Y (male) chromosome, indicating that regenerated tissue originated exclusively from the progenitor cell of the periosteal graft. Karyotypes of the cells from the other 67% were mosaics (both female and male); thus, their cellular origin was from both the periosteal allograft and the pluripotential mesenchymal cells in the subchondral tissues.

Cellular origin and evolution of neochondrogenesis in major full-thickness defects of a joint surface treated by free autogenous periosteal grafts and subjected to continuous passive motion in rabbits.

A graft of periosteum from the tibia of 27 rabbits was incubated in vitro with tritiated thymidine for 24 hours and then transplanted into a full-thickness defect in the patellar groove. The rabbits were managed after the operation on continuous passive motion (CPM), and the joints excised at intervals of two to 21 days. After one week the cells had begun to synthesize glycosaminoglycan and by two weeks the tissue resembled immature hyaline cartilage. Thymidine-labeled cells were seen throughout the entire regenerated tissue. The cellular origin of the hyaline-like tissue that filled the defects was the progenitor cells of the periosteal graft.