Thumb Arthritis: Ligament Reconstruction Tendon Interposition (LRTI)

Thumb Arthritis: Ligament Reconstruction Tendon Interposition (LRTI)

This video will demonstrate a ligament reconstruction tendon interposition procedure, also known as an LRTI, on a patient with thumb arthritis. Arthritis in the base of the thumb occurs at the carpometacarpal joint, also known as the CMC joint. This joint is where the thumb's metacarpal bone meets the trapezium, a bone in the wrist.

The procedure aims to relieve pain by removing the trapezium bone and relocating a nearby tendon in its place to provide a cushion to the arthritic joint. This tendon is called the flexor carpi radialis, or FCR. An indwelling screw will be used to attach the tendon to the bone in its new position.

To begin, the surgeon will make an incision overlying the CMC joint of the thumb on the patient's left hand. Careful attention will be made to avoid nerves, tendons, and vessels when approaching the surgical site. All structures will be protected with surgical retractors during the procedure. The capsule of tissue around the CMC joint will be opened. Here is the CMC joint.

The surgeon will remove soft tissue around the trapezium in preparation for its removal. A small bone saw is used to cut the trapezium into smaller pieces for easier removal. The bone will then be removed. Here is the newly created open space. The FCR tendon is then identified. This tendon will be released higher in the forearm.

Once the tendon is identified and freed, it will be cut by the surgeon in preparation for relocation at the base of the thumb. This is then pulled gently into the base of the thumb through the forearm. It will then be split into 2 halves. A wire will then be placed in the thumb metacarpal bone in preparation for the incoming screw.

A drill will be placed over the wire, and a hole will be made in the bone to create a tunnel. A mesh-like straw and flexible wire instrument will be used to shuttle the tendon through the recently drilled tunnel. The end of the tendon will be placed into the mesh-like straw end of the instrument, which is then fed through the base of the tunnel and out the top. Here is the tendon now tunneled through the bone.

The screw will then be placed in the top of the hole to hold the tendon in place. The remaining half of the tendon will be sewn so it can be bundled and placed into the base of the open joint. The other tendon half will be sewn in a similar fashion and also placed into the open joint. The new cushion will be sewn into place and the capsule of tissue will be repaired over the new cushion.

X-rays showed the location of the removed trapezium and although not visible on x-rays, the tendon graft now lies in this spot as a cushion for the base of the thumb. The incision will be closed, and the surgery will be complete.