Fusion of the first metacarpophalangeal joint for post-traumatic conditions.

Fusion of the metarcarpophalangeal joint of the thumb is an accepted treatment in the management of instability or osteoarthritis following trauma to this joint. A review was made of the literature and 30 of the senior author's (RH) patients who had had this operation, in order to determine what effect the operation had on the pain in their thumb, any symptoms of instability, interference with work and daily activities, and strength in the hand. All of the patients achieved bony union and the average angle of fusion was 7.6 degrees of flexion. All of the patients were either satisfied or very satisfied with the results of the operation, and had an average increase of 6.3 points on a 12 point rating scale. However, 48% of patients had some mild intermittent pain and 43% complained of some difficulty with fine motor tasks. Twelve patients were able to attend for formal evaluation including the Jebson and Crawford Hand Function Tests which revealed some decrease in hand function in all of those tested. It was concluded that this method of arthrodesis of the metacarpophalangeal joint of the thumb gives reliable results, with high patient acceptance, but does not result in an entirely normal thumb or hand function.

Silastic replacement of the trapezium.

A retrospective study has been made of the long-term results of silastic replacement of the trapezium, including functional, clinical and radiological assessment of 43 hands, one to 13 years postoperatively. The results showed good function and relief of pain in 88% of hands. Radiolucent bone lesions, presumably due to silastic particle reaction, occurred in 53% of hands, but their presence did not correlate well with symptoms. Four patients (9%) developed significant synovitis which was improved by removal of the prosthesis. In this series, clinical silastic synovitis occurred in the first four years, and its incidence did not increase with further follow-up to 13 years.

Sensory effects of pulling or vibrating exposed tendons in man.

The role of muscle receptors in proprioception has been demonstrated in a variety of ways (for review see McCloskey, 1978) but is still doubted by some. One simple but critical experiment has produced conflicting results: when a tendon of a conscious subject is exposed at operation under local anaesthesia, and pulled so as to stretch its muscle while the joint at which the muscle acts is held still, the subject is claimed by some to perceive nothing (Gelfan and Carter, 1967; Moberg, 1972), while others claim that the subject feels that the joint seems to move (Matthews and Simmonds, 1974). In the present study 4 patients were studied while undergoing surgery at the wrist or hand under local anaesthesia, and a more extensive study was carried out in the laboratory on the exposed, transected tendon of extensor hallucis longus of one of the authors (D.I.McC.). All 4 patients and the experimental subject detected stretches imposed on their muscles, and reported them as rotations of the joint or joints to which those muscles attach. In all cases the movements reported were in the direction of joint rotation that would normally stretch the muscle tested. In the experimental subject it was shown that stretches were detected with comparable acuity to that demonstrable for the detection of movements imposed on the intact toe. Also, the subject was able to detect, as joint movements, sinusoidal stretches of less than 1 mm imposed on the tendon at 1 or 5 Hz. The experimental subject experienced illusory movements of plantar flexion of the big toe when longitudinal vibration at 100 Hz, 20 to 100 microns amplitude was applied. These were sometimes partly masked by spread of the vibration through the foot. These vibration-induced illusions correspond to those reported by Goodwin et al. (1972) for transverse vibration applied through the skin. The subject could maintain a constant tension through the tendon in a contraction in which his effort was held constant. If, during such an effort, a downward movement was imposed on the toe to which the tendon normally connects, or the skin on the bottom of the toe was scratched, achieved tension fell.

A review of 100 flexor tendon reconstructions with prosthesis.

A series of one hundred cases where silicone rods were used to prepare a bed for flexor tendon grafting is examined, the main indication for this technique being circumstances where one stage tendon grafting was likely to have a poor result. The main complications noted were a synovitis around the silastic rods, infection, and loss of the distal attachment of the silastic rod. The overall results were satisfactory.