PRCT: Ligament Reconstruction & Tendon Interposition With a Joint Spacer for Trapeziometacarpal OA (TMC/PyroDisk)

A Randomized Prospective Study Comparing Ligament Reconstruction and Tendon Interposition (LRTI) With a Joint Spacer (Ascension PyroDisk) for Trapeziometacarpal Osteoarthritis.

The purpose of this study is to compare the effectiveness of two types of operative treatment in terms of resolving symptoms, improving function and also with respect to x-ray outcomes. The hypothesis is that insertion of a spacer will provide similar symptomatic relief, but improved long term gains in key and tripod pinch strength when compared to LRTI.

Trapeziometacarpal (TMC) arthritis is a common condition, which occurs when the cartilage (tissue) covering the bones at the joint at the base of the thumb wear away. This condition occurs in 10% of women and 1% of men. There is controversy regarding the best treatment of this condition and many surgical techniques are in common use. One of these involves removing the wrist bone (trapezium) at the base of the thumb and, using a tendon from the forearm, reconstructing an important ligament, which contributes to the stability of the thumb. This is known as a Ligament Reconstruction and Tendon Interposition (LRTI). A newer type of operation involves the insertion of a Ascension PyroDisk which is made from a thick pyrocarbon layer encasing a graphite core with a small amount of tungsten. These materials have been shown to be safe when implanted in the body. The PyroDisk is a disk shaped design which has a curved surface designed to fit between the bony surfaces of the trapezium and the metacarpal, reducing pain and allowing for full movement of the joint. It contains a hole in the center through which a strip of tendon can be passed and helps hold the disk in place. This research study is designed to determine the effectiveness of the Ascension PyroDisk spacer when compared to the LRTI procedure described above. The effectiveness of both of these procedures will be determined by comparing range of motion, grip and pinch strength, x-rays, function and return to work. It is important to compare both procedures, as it is not known which procedure is the most effective.

Dorsal radial incision, capsulotomy between EPB and APL protecting the radial artery, trapeziectomy using a cruciate osteotomy and rongeurs, creation of a metacarpal base bone tunnel using a high speed burr, harvesting of entire FCR tendon through two transverse volar incisions, ligament reconstruction and tendon interposition using "Fibre Wire" suture. Closure of capsule with Vicryl. Closure of skin with running Prolene suture.

Dorsal radial incision, capsulotomy between EPB and APL protecting the radial artery, distal 2 mm of trapezium and dorsal cortex of both trapezium and metacarpal removed using osteotomes/rongeurs. A hole is drilled through the trapezium from dorsal to resected distal surface, and a second hole is drilled through the first metacarpal from the resected base to the dorsal surface. A slip of FCR is harvested. The tendon is woven through the trapezium, the central hole in the device, and the metacarpal tunnel then sutured back onto itself. Closure of capsule with Vicryl. Closure of skin with running Prolene suture.

Inclusion Criteria: isolated trapeziometacarpal osteoarthritis duration of symptoms of at least six months failure to respond to non-operative management age 50 or older less than 30 degrees of ipsilateral MCP hyperextension British Columbian resident living in the Lower Mainland and available for protocol follow-up Exclusion Criteria: previous surgery for TMC arthritis other significant ipsilateral wrist or hand pathology a history of inflammatory arthropathy a requirement for concommitant surgery for another condition any previous hand or wrist fracture

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