The scapholunate interosseous ligament (SLIL) is the most important intrinsic carpal ligament, maintaining the proximal carpal row integrity and preventing DISI deformity. Its three components (dorsal, proximal membranous, volar) provide different contributions: the dorsal is strongest and most important for reconstruction; the proximal is weakest; the volar provides secondary stability. Chronic SLIL tears produce the SLAC (scapholunate advanced collapse) wrist arthritis pattern.
| Origin | Scaphoid proximal articular margin |
|---|---|
| Insertion | Lunate proximal articular margin |
| Actions | Maintains scapholunate articulation and prevents DISI collapse; the key intercarpal stabiliser of the proximal carpal row |
|---|
The SLIL is reconstructed using the three-ligament tenodesis (Brunelli modified) — a strip of flexor carpi radialis is passed through a scaphoid bone tunnel and attached to the dorsal radius and lunate to replicate SLIL function. The RASL (reduction and association of the scaphoid and lunate) screw provides temporary rigid stabilisation for healing. These techniques are appropriate for dynamic instability; static instability may require proximal row carpectomy.
Three-ligament tenodesis or RASL screw for chronic SLIL instability preventing SLAC wrist degeneration.
