[Midcarpal fusion with the spider plate].

OBJECTIVE: Pain relief while preserving wrist motion in advanced carpal collapse.

INDICATIONS: Advanced carpal collapse stage II/III due to scaphoid non-union, scapholunate ligament tear, idiopathic radiocarpal osteoarthritis, aseptic osteonecrosis of the scaphoid (Preisser's disease). A relative indication is chronic midcarpal instability.

CONTRAINDICATIONS: Osteoarthrisis of the lunate. Radiocarpal instability with ulnar translation of the wrist.

SURGICAL TECHNIQUE: Dorsal curved incision between the 3rd and 4th dorsal extensor compartment. Partial wrist denervation (posterior interosseous nerve). Raising of a radial pedicled capsule flap. Complete extirpation of the scaphoid without fragmentation. Cartilage removal of all the joint facets for arthrodesis. Reduction of the lunate and temporary fixation with K wires between the triquetrum and capitate and the triquetrum and lunate. Milling the plate hole exactly in central position of the four carpal bones. The plate should not protrude from the bone to avoid impingement with the dorsal limb of the radius. Transferring of spongiosa harvested from the removed scaphoid into the arthrodesis gap. Fixation of the 8-hole plate with 2 screws in each of the four carpal bones. Fluoroscopy of the screw fitting. Control of the correct wrist articulation (motion test). Lavage of the wrist. Suture of the capsule flap. Redon drain, wound closure, dorsal splinting.

POSTOPERATIVE MANAGEMENT: Dorsal splint for 3 weeks; finger mobilization up to complete fist closure starting on postoperative day 1. From week 4-6, active wrist motion, from week 7-10 with increasing load. Return to work after 11-12 weeks. CT scan in cases of delayed union, abnormal function, or persistence of pain.

RESULTS: Between 2002 and 2008, 36 four-corner fusions (32 male, 4 female) with the spider plate were performed in 24 right and 12 left wrists. The mean age of the patients at surgery was 48 years (range 32-71 years). Follow-up examinations were performed in 11 patients. The Krimmer and Rudolf scores were determined: 1 excellent, 7 good, 2 satisfactory, and 1 poor result were found. The mean grip strength was 51% relative to the opposite wrist. The mean range of motion (ROM) for wrist extension/flexion was 56% of the opposite side. Wrist extension/flexion averaged 24/0/32° and ulnar/radial deviation was on average 20/0/19°. Pain during activity was on average 2.2 based on the visual analogue scale (0-10). One delayed bony union due to a screw breakage, which required total wrist fusion, was observed.