Faculty Bibliography

Trapeziectomy, ligament reconstruction and tendon interposition arthroplasty is one of the most commonly performed procedures to address pain and instability due to osteoarthritis at the basal joint of the thumb. To determine the effect of stress on first metacarpal subsidence, 15 ligament reconstruction and tendon interposition basal joint arthroplasties were evaluated after a mean follow-up of 32 months. Radiographs were obtained of the arthroplasty at rest and then with maximal effort key pinch stress, which is known to subject the first carpometacarpal joint to considerable axial compression stress. Compared with the preoperative x-rays, the first metacarpal had subsided 21% of the arthroplasty space at rest. Under stress, the first metacarpal was found to subside another 10.5% in height. No subluxation of the metacarpal base could be detected. Key pinch strength improved 17% from the preoperative strength. Tip-to-tip pinch strength improved 17% from the preoperative measurement. Grip strength improved 17% from the preoperative measurement. Grip strength was 9% greater than the preoperative grip strength. There was no statistical association between the amount of first metacarpal subsidence and follow-up key pinch, tip pinch, or grip strength. With axial compressive loading of the arthroplasty, such as in lateral pinch, there is some further proximal migration of the first metacarpal, but this is minimal and does not correlate with functional outcome

Custom-designed miniature load-cells were inserted into the distal end of the ulna and the proximal end of the radius in ten fresh-frozen forearms from cadavera. The forces transmitted through the bones at these sites were measured under 134 newtons of constant axial load that was applied through the metacarpals as the forearm was rotated from 60 degrees of supination to 60 degrees of pronation. The simultaneous measurements of these forces allowed the calculation of radioulnar load-sharing at the wrist and the elbow as well as the calculation of the amount of force that was transferred from the radius to the ulna through the interosseous membrane. With the elbow in valgus alignment (that is, with contact between the radial head and the capitellum), the main pathway for load transmission through the forearm was direct axial loading of the radius; measurements from both load-cells were unaffected by the angle of elbow flexion. When the forearm was in neutral rotation, the mean force in the distal end of the ulna averaged 2.8 per cent of the load applied to the wrist and the mean force in the proximal end of the ulna averaged 11.8 per cent; this indicated that only a small amount of tension developed in the interosseous membrane. With the elbow in varus alignment (that is, with no contact between the radial head and the capitellum), load was transmitted through the forearm by a transfer of force from the radius to the ulna through the interosseous membrane. When the forearm was in neutral rotation, the force in the distal end of the ulna averaged 7.0 per cent of the load applied to the wrist and the force in the proximal end of the ulna averaged 93.0 per cent; the force through the interosseous membrane decreased with supination of the forearm. Testing with the elbow in valgus alignment and shortening of the distal end of the radius in two-millimeter increments produced corresponding increases in force in the distal end of the ulna and decreases in force in the radial head. The forces through the interosseous membrane remained low after each amount of radial shortening

Mirror hand is one of the rarest congenital differences of the upper extremity. Typically, there is absence of the radius, duplication of the ulna, and 7 digits in mirrored symmetry about the middle finger. We report a case of a rarer subset of hand duplication in which there is a normal radius and ulna and a hand with 8 digits. The patient underwent surgery to excise the radial 3 digits and to reconstruct the remaining radial digit to function as an opposable, 2 phalanx thumb. Wrist extension was augmented by transferring the digital extensors from the excised fingers to the radial wrist extensors

Carpometacarpal dislocations of the ulnar four joints are rare injuries that are usually associated with high-energy trauma. Given the small number of cases reported, there exists some controversy regarding their optimal management. The case of a 27-year-old man who sustained a dorsal dislocation (without associated fractures) of the ulnar four carpometacarpal joints as a result of a fall from a height is presented. The literature regarding these hand injuries is reviewed, and the need for anatomic reduction and stabilization is discussed

Delayed rupture of a flexor tendon in the hand due to the presence of a retained foreign body is rare. We present the case of a late flexor pollicis longus rupture 30 years after traumatic implantation of a glass fragment. The foreign body had migrated distally a distance of 4.5 cm from the site of the original injury and eroded into the flexor tendon sheath. Thumb function was restored with a flexor digitorum superficialis tendon transfer from the ring finger with excellent results