Preoperative percutaneous arthrography provides detailed information for treatment of Wassel type IV thumb...

We aimed to detect whether percutaneous arthrography can provide detailed information for surgery for Wassel type IV thumb duplication prior to skin incision.

Percutaneous arthrography of the metacarpophalangeal (MP) joints was performed in eight infants. Of these, three patients had interphalangeal (IP) joints, in which thumb duplication at the MP joint (Wassel type IV) was detected on radiography. Based on the arthrographic findings, we designed the skin incision and determined whether and where osteotomies were required to correct the angular deformities before surgery.

Arthrography revealed the cartilaginous position and shape, shown as a black area on radiographs. Two patients demonstrated fibrous attachment between the proximal phalanx of the radial thumb and the capsule of the ulnar thumb. One patient had two completely separated MP joints. Cartilaginous connection between the two proximal phalanges was present in another two cases. The remaining three patients demonstrated a common joint between the duplicated proximal phalanges, sharing a common articular space with the MP joint, with the metacarpal head's surface forming two facets separated by a crease in the middle. IP joint arthrography was performed in three patients who presented with angular deformity.

Percutaneous arthrography can provide detailed information prior to skin incision. Furthermore, our arthrographic findings coincided with the practical situations we observed intraoperatively. Our experience indicates that preoperative percutaneous arthrography should be performed routinely in more cases and classified based on articular configuration to aid in the selection of surgical treatment.