The boutonniere deformity.

Understanding the pathophysiology of the boutonniere deformity requires a complete understanding of the anatomy of the dorsal tendon apparatus. This unique tendon mechanism often becomes unbalanced, requiring correction of its components. Splinting is the cornerstone of treatment for the boutonniere deformity. In the acute stage, splinting ensures that the continuity of the central tendon to its insertion into the middle phalanx is maintained, and in the chronic stage, its function is to correct the flexion contracture of the PIP joint and stretch the retinacular ligaments. Splinting is also important postoperatively because it permits healing of the central tendon and lateral bands in their correct anatomic positions. Without proper splinting, the patient with the boutonniere deformity could not be successfully treated. Frequently, surgery is necessary, and the choice of procedure depends on the stage of the condition and the extent of the defect in the extensor tendon mechanism. The procedure also depends on the success of the splinting program and stretching of the tight retinacular structures. If passive joint mobility can be restored and if tendon imbalance and retinacular tightness persist, rebalancing is necessary. This rebalancing can be accomplished by a tenotomy of the terminal extensor tendon, a lysis or release of the retinacular structures, or release of the insertion of the extensor tendon at the base of the proximal phalanx. Reconstituting the defect in the central tendon over the PIP joint is accomplished by using a variety of procedures, including mobilization and advancement of the more proximal portion of the central tendon, shifting the lateral bands, or a tendon graft.

Treatment of skin loss in the hand.

In treating skin loss of the hand, the surgeon must be aware of the placement of skin and scars, the unique quality of palmar skin, the tendency of skin grafts to hyperpigment, the need for pain-free and well-padded amputation stumps that are free of painful neuromata and poorly padded phalangeal remnants. Skin grafts, palmar skin loss, regional flaps, distant flaps and local flaps are discussed. The histology and function characteristics of normal skin of the hand are reviewed.

A phalangeal fracture model--quantitative analysis of rigidity and failure.

Nine types of internal fixation techniques were tested in 4-point bending using a pig metacarpal model for phalangeal fractures. Levels of bending rigidity and bending moments at failure were determined, and the modes of failure are described. Plate and screw fixation afforded the greatest rigidity, and epiphyseal fractures occurred, leaving intact the test section. Flexible wire loop fixation failed by wire cutting into bone when a square knot was used. Twisted wire unraveled when placed in tension. Depending on the fracture type and the wire placement. Kirschner wires failed either by slipping in the bone, twisting in the bone cortex, or bending at the bone cortex interface. Rigidity varied widely depending on the way in which the wires were employed.

Pitfalls in management of fingertip injuries and hand lacerations.

Fingertip injuries and lacerations of the hand are often dismissed as inconsequential, although this attitude can lead to more serious problems. Appropriate and timely treatment of these injuries prevents loss of function, preserves digital sensibility, and lessens the need for reconstructive surgery.

Mechanical analysis of Kirschner wire fixation in a phalangeal model.

Transverse divisions of the mid-shaft of freshly frozen pig metacarpals were fixed with Kirschner wires of two sizes and using four different configurations. Compared to the usual cross-pin fixation using wires of 0.889 mm. four wires (0.712 mm) eccentrically placed and with their ends hooked provided a 300% improvement in bending rigidity and 170% in bending movement.