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Using a Joint Spacer in a Pinch

Surgeons are trying new ways to restore the trapeziometacarpal (TMC) joint at the base of the thumb in patients with osteoarthritis (OA). Pain and weakness from pain reduces pinch strength from this problem. Without a strong pinch, patients are limited in how they can use that hand.

In this pilot study, surgeons compared two ways to treat TMC OA. The first was a standard removal of the trapezium bone with a nearby tendon used to stabilize the joint. The operation is called a tendon arthroplasty. The tendon is actually rolled up into a ball and tucked into the space left by the missing bone. The second was the removal of the trapezium bone with a special T-shaped device put in the open space.

The joint spacer used in the second group was biodegradable. It works by giving the local tissue a place to lay down new healing tissue. This is called a scaffold for tissue ingrowth. The spacer slowly disintegrates as the new tissue is formed. Over time any pressure or load through the joint is transferred from the device to the newly forming joint capsule.

Results were measured by pain, strength, motion, and stability. All but one patient was followed for three years. Everyone was pain free and had equal motion after the operation. The main difference between the two groups was pinch strength. Patients with the biodegradable spacer had increased pinch strength compared to the tendon arthroplasty group.

The authors conclude that the use of a TMC spacer gives equal, if not better, results than tendon arthroplasty for TMC OA. It may be the treatment of choice for anyone with TMC joint pain and damage who needs good grip function and pinch strength.

References: Anders Nilsson, MD, PhD, et al. Results From a Degradable TMC Joint Spacer (Artelon) Compared with Tendon Arthroplasty. In Journal of Hand Surgery. March 2005. Vol. 30A. No. 2. Pp. 380-389.

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