The supination effect of tendon transfer of the flexor carpi ulnaris to the extensor carpi radialis brevis or longus: a cadaveric study.

Flexor carpi ulnaris (FCU) transfer to the extensor carpi radialis brevis (ECRB) and/or the extensor carpi radialis longus (ECRL) has been commonly used to provide wrist extension. The ability of this wrist extension transfer to also provide forearm supination has been inferred but not formally investigated. This laboratory study investigated the forearm supination effect of FCU transfer to the ECRB and to the ECRL in a cadaveric model. Two vectors of pull were investigated: freeing either the distal one third or the distal two thirds of the FCU ulnar origin. Five fresh-frozen, above-elbow, non-matched cadaveric specimens placed in a mounting device that allowed the arm to rotate about its ulnar axis starting from a full pronated position were measured for resultant supination after tendon transfer and loading. This study showed that the transfer of the FCU into either the ECRB or the ECRL resulted in no significant difference in maximum supination. The vector of origin, however, did significantly affect the maximum supination obtained. Releasing the distal two thirds of the FCU ulnar origin resulted in a mean supination that was significantly greater than the mean supination achieved with releasing the distal one third of the FCU ulnar origin. We concluded that in the cadaveric model, transfer of the FCU into either the ECRB or ECRL provided similar resultant supination and that freeing the distal two thirds of the FCU ulnar origin provided significantly more supination than freeing only the distal one third. For the hand surgeon treating wrist flexion in combination with forearm pronation deformity, transfer of the FCU into the ECRB and/or the ECRL can be used to concomitantly provide wrist extension and forearm supination.

In vivo kinematics of the rabbit knee in unstable models of osteoarthrosis.

The effects of osteoarthrosis inducing surgery on the kinematics of the rabbit knee were evaluated in vivo. A video motion analysis system was used to track reflective markers attached to two pins fixed in both femur and tibia, and from these data knee kinematics were computed. The control for all measurements was the gait after pins were implanted, but the knee was unaltered. Both a release of the anterior cruciate ligament and a partial medial meniscectomy were then performed, and the animals' gait was recorded at 4, 8 and 12 weeks after knee surgery. Knee kinematics were described by three translations and three rotations and were analyzed in terms of maximum and minimum values and range of motion. Statistical comparisons of these data between control and operated knees were made using Wilcoxon's signed rank test. Results showed an initial increase in maximum anterior displacement which returned to normal after 12 weeks. In addition there was a persistent increase in knee adduction and an increase in the minimum value of external rotation over the 12 week period. At 12 weeks after surgery there was no change in range of any measurable kinematic parameter. Overall, the changes in joint kinematics following partial medial meniscectomy and release of the anterior cruciate ligament were small, suggesting that altered joint kinematics might not be a critical factor in the development of osteoarthrosis in this animal model.