Wrist Instability (Scapholunate Ligament Injuries): Salvage Procedure (Fusion)

Wrist Instability (Scapholunate Ligament Injuries): Salvage Procedure (Fusion)

This video will demonstrate a four-corner fusion for an advanced scapholunate ligament injury known as scapholunate advanced collapse or SLAC wrist. SLAC wrist is a progressed outcome of an untreated scapholunate ligament injury that results in arthritis and instability in the wrist that may lead to significant pain, decreased range of motion, and weakness.

The surgeon will be demonstrating a procedure called a four-corner fusion, in which 4 of the wrist bones will be realigned and fused together. The surgeon will be using bone staples to achieve the desired result. In a four-corner fusion, the lunate and the capitate will be fused together to form one-half of the four-corner shape. The other half will include fusion of the triquetrum and the hamate. The scaphoid is removed to provide more motion after surgery and to decrease the development of arthritis after the fusion.

This procedure will be demonstrated on a cadaveric specimen. Here is a right hand. The surgeon has already made an incision on the top of the wrist and is identifying the relevant wrist bones for the procedure: the scaphoid, the lunate, the triquetrum, the capitate, and the hamate. Here, the scaphoid bone has already been removed.

To prepare the bones for fusion, the surgeon has removed the damaged arthritic ends of the bones so they can eventually heal and fuse together. To ensure the position of the fusion is optimal, x-rays will be done prior to placing the staples. This x-ray shows the scaphoid bone removed and temporary wires holding the bones in proper position.

The surgeon will prepare a hole for the staple using a drill and drill guide. The surgeon is drilling the lunate bone first. A temporary pin will be used to hold this spot after the drill is removed. The surgeon will then drill the capitate bone, and another temporary alignment pin will be used.

The surgeon is now preparing the staple that will be used to hold the bones together. The staple is open slightly to fit the distance between the 2 recently drilled bones. Before inserting the staple, the temporary pins are removed. The drill guide will be tilted back to expose the 2 drill holes and removed as the staple and the positioner are dropped into place. The staple will be partially inserted, and the positioner will be removed. From here, the surgeon will use an instrument called a bone tamp to place the remaining staple in place.

Here is an x-ray of the staple holding the lunate and capitate in place. These steps will then occur for the triquetrum and hamate bone staple. Here is an x-ray showing the 2 final staples in place. With live x-ray, the wrist shows its retained range of motion, and again when looking directly at the fusion, the wrist moves smoothly without the staples interfering. The incision will be closed, and the surgery is complete.