Sulphur colloid bone scan assessment of femoral head vascularity following subcapital fracture of the hip.

The study was done to determine femoral head vascularity in the immediate postfracture stage as assessed by 99m Tc-sulphur colloid bone scanning and tetracycline uptake in the excised femoral heads of 30 patients with subcapital fractures treated by primary hemiarthroplasty. Twenty-four cases were diagnosed avascular by the scan, and this was confirmed by the absence of tetracycline labelling in all 24. Two cases were vascular by the scan, and this was confirmed by tetracycline labelling. The scan was inaccurate in only four cases, where the head appeared vascular by the scan, but avascular by tetracycline labelling. Sulphur colloid is helpful in predicting femoral head vascularity in the immediate postfracture phase.

Distal humeral fractures in the adult.

Distal humeral fractures in the adult often are complicated by pseudarthrosis, pain, and limitation of motion. Of 29 adult patients with distal humeral fractures treated in teaching hospitals, 22 obtained acceptable results. Twenty-two percent of those treated by open methods and 36% of those treated by closed methods had unacceptable results. Ninety percent of the patients starting physiotherapy within six weeks of injury recovered well, while over half of those starting physiotherapy after six weeks had unsatisfactory results. Even comminuted fractures healed when treated by internal fixation and started early on exercises. The most important indicator of end result was the starting time of physiotherapy. Rigid internal fixation is recommended for this fracture, but if stability is not likely to be accomplished by open reduction, nonoperative measures are preferable.

Indentation stiffness of the cancellous bone in the distal human tibia.

Total ankle arthroplasties tend to fail mainly on the tibial side. Fifteen fresh amputation specimens were used for assessment of the stiffness of the cancellous bone in the distal tibia. Because all current ankle replacements sacrifice the subchondral bone plate, the change in stiffness of cancellous bone was studied in transverse sections taken proximal to the subchondral plate of the ankle. The articular cartilage was removed from the tibial plafond, and serial 1-cm sections were taken, radiographed, and tested in compression on an Instron 1125 Universal Testing machine with the use of a 4-mm-diameter indentor. In the distal tibia, it was found that subchondral bone has an elastic modulus on the order of 300-450 MPa; removal of the subchondral bone plate reveals bone with a compressive resistance that is 30%-50% lower than with the bone plate intact; there is virtually no resistance to compression in the trabecular bone at a distance of more than 3 cm proximal to the subchondral bone plate; and stiffness characteristics in the distal tibia parallel the radiographic appearance of the trabeculae. The strongest cancellous bone in the region of the distal tibia is that near the subchondral bone plate. This material should be preserved, if possible, in the surgery for total ankle implants.