Abstract
The ulnar deviation of the fingers is a part of a developed collapse deformity of the wrist and hand. The central pillar disorder of the hand begins with ulnar translocation of the carp in the frontal plane.
According to Shapiro's theory, the carpus and metacarpal landscape behave biomechanically as one unit and the ulnar deviation and radial inclination of the wrist is followed by the radial inclination of the metacarpus and the ulnar deviation of the fingers. In the area of MCP joints, there is a tendency to ulnarly dislocate the course of the extensor tendons of the 2nd to 5th finger due to the loosening of the ligament apparatus.
Their slipping from the top of the MCP joint into the intermetacarpal spaces results in a limitation of their extension ability. Extensors in their new, pathological course become ulnar ductors of the fingers and further strengthen and fix ulnar deviation.
Surgical interventions that lead to the capture of the ulnar carpus deviation prevent the collapse deformity and thus ulnar deviation of the fingers. The basic procedure comprises early synovectomy of the dorsal portion of the carpus and peritenosynovectomy of the extensor tendons followed by tendon transposition, synovectomy of the MCP joints together with interventions that repose the physiological course of the extensor tendons.
Limited joint fusions in the proximal row of carpal bones are also used. Tonalization of radial collateral ligaments and transposition of insertions of ulnar interosseal and lumbrical muscles to the radial part of the proximal phalanx of the next finger is one of the most complicated surgical procedures in this region.
Their combination with implantation of artificial MCP joint replacements is necessary in developed cases.