Extra-articular subcutaneous "inverted king post-truss" ligament reconstruction for severe swan neck deformity (snapping finger).

A swan neck deformity (SND) can be well tolerated for a long time, until the appearance of a disabling "snapping finger". In its most advanced condition, the other hand is needed to initiate finger flexion. We propose a technique of extra-articular, subcutaneous ligament reconstruction with an "inverted king post-truss" configuration use in roofs and to reinforce railway bridges. An artificial ligament (MaxBraid™ polyethylene surgical suture, 5 metric, Biomet) makes a figure of eight between transosseous tunnels in the proximal and middle phalanges, crossing over top of the A3 pulley. We limited our series to severe SND cases with "snapping finger". We excluded isolated SNDs without functional disability. Eleven patients were followed for 3.4 years on average. The cause was an acute injury 8 times (7 balloon accidents), rheumatoid arthritis 2 times and overuse once (saxophone). Only one case was a poor outcome of mallet finger. The 11 patients were reassessed by a telephone survey. Two patients underwent reoperation: one for a ligament rupture, the other one for a knot that became untied. One patient had a suspected late rupture but without recurrence of the disabling snapping finger. The 11 patients considered themselves improved by the intervention. Nine patients did not notice any difference between their operated finger and the contralateral side. Return to manual activity was possible once the skin had healed. The technique is simpler than the spiral oblique retinacular ligament (SORL) reconstruction technique described by Thomson-Littler and also less demanding because it does not involve the distal interphalangeal joint. It requires only a short incision in the volar crease of the proximal interphalangeal joint. No tendon or ligament is sacrificed. Neither postoperative immobilization nor lengthy physical therapy is needed. Complications can be avoided by selecting the appropriate artificial ligament material and careful knot tying.

CT scan method accurately assesses humeral head retroversion.

Humeral head retroversion is not well described with the literature controversial regarding accuracy of measurement methods and ranges of normal values. We therefore determined normal humeral head retroversion and assessed the measurement methods. We measured retroversion in 65 cadaveric humeri, including 52 paired specimens, using four methods: radiographic, computed tomography (CT) scan, computer-assisted, and direct methods. We also assessed the distance between the humeral head central axis and the bicipital groove. CT scan methods accurately measure humeral head retroversion, while radiographic methods do not. The retroversion with respect to the transepicondylar axis was 17.9 degrees and 21.5 degrees with respect to the trochlear tangent axis. The difference between the right and left humeri was 8.9 degrees. The distance between the central axis of the humeral head and the bicipital groove was 7.0 mm and was consistent between right and left humeri. Humeral head retroversion may be most accurately obtained using the patient's own anatomic landmarks or, if not, identifiable retroversion as measured by those landmarks on contralateral side or the bicipital groove.

Potential excursion and relative tension of muscles in the shoulder girdle: relevance to tendon transfers.

Muscles used for transfer ought to have adequate structural properties. The purpose of this study was to provide a database of potential excursion (muscle excursion without reference to connective tissue restraints) and relative tension (muscle physiologic cross-sectional area in percentage among a group) in shoulder girdle muscles. Thirteen muscles in 13 human cadavers aged 17 to 89 years at death were studied. Potential excursion ranged from 6.7 cm (supraspinatus) to 33. 9 cm (latissimus dorsi). Relative tension ranged from 1.7% (levator scapulae) to 20.9% (deltoid). Significant discrepancies were found between the properties of some of the muscles used as transfers around the shoulder and the properties of the muscles for which they are commonly used as substitutes. Despite the limitations of cadaveric studies and the fact that many other factors are involved in muscle transfers, this database of structural properties of shoulder girdle muscles may help when planning tendon transfers around the shoulder.