Evolution of Technology

Scaphoidectomy and Four Corner Fusion

The scaphoidectomy and four corner fusion was developed to limit the painful motion between the carpal bones in the hand by removing some of the articulations and replacing them with fused joints. Early techniques involved holding the bones in place with Kirschner wires (K-wires), however compression was difficult to maintain, and so screws fired across the individual joints was trialed, along with compression staples, both with better fusion rates.

The development and implantation of a circular dorsal plate has grown in favor for its ease of use and rigidness to allow for early active range of motion exercises.

Evolution of Procedure

Scaphoid Lunate Advanced Collapse Surgery

Operative treatment for SLAC wrist is dependent on how far the osteoarthritis has progressed. In early cases, the damaged ligament between the scaphoid and lunate can be recreated and the end of the radius can be resected to allow for less contact pressures, hopefully slowing of the arthritic process. Sometimes the nerves suppling the pain sensation, such as the anterior and posterior interosseous nerves (AIN and PIN), can be resected to decrease the pain in the wrist from the osteoarthritis.

If the osteoarthritis does not involve the articulation between the lunate and capitate bones and the ligament between the radius, scaphoid and capitate is still intact, then a proximal row carpectomy can be performed. This procedure involves removing scaphoid, lunate and triquetrum, enabling the more distal row of bones in the hand to articulate at the wrist.

When the SLAC wrist has progressed to involve the cartilage between the lunate and capitate, then a scaphoidectomy and four corner fusion is indicated. This procedure removes the scaphoid and then forms a fused conglomeration between the lunate, triquetrum, capitate and hamate bones in the hand. This new fused bone can move as a single unit at the wrist and the previous pain caused by osteoarthritis between these bones is eliminated.

Evolution of Diagnosis

Scaphoid Lunate Advanced Collapse

Scaphoid Lunate Advanced Collapse (SLAC wrist) is a progressive osteoarthritis caused by instability between the scaphoid and lunate carpal bones. When the ligament between those two carpal bones tears, either though trauma or degeneration, the scaphoid naturally flexes forward and the lunate extends backwards resulting in a Dorsal Intercalated Segment Instability (DISI deformity). The unnatural position of these bones wears the cartilage off the bones with which they articulate, creating progressive pain and osteoarthritis in the hand and wrist.