Arthrodesis Frequently Reduces Pain and Function in Trapeziometacarpal Arthritis
Trapeziometacarpal arthritis (arthritis below the base of the thumb), the second most common site for arthritis in the hand and is not only painful, but can cause great disability, impacting on quality of life. Usually, once the damage to the joint is severe enough that pain can't be managed without surgery, the options are arthroplasty (replacement) or arthrodesis (fusing the bones).

The choice of which procedure depends on several factors, one of which is age. Patients under 50 years old or who need to have a strong grip are usually candidates for fusion and older patients or those who don't place a lot of demand on the joint are usually given a replacement. That being said, the study findings about how successful fusion is are confusing. Some studies report fusion rates as high as 100 percent, while others only report half that. Some studies report patients with fusions being very pleased with the results, but others report a greater increase of arthritis in surrounding joints after fusion surgery.

The authors of this article evaluated the outcomes of patients over 33 years of the procedure in their particular institution. Researchers found eligible records of 241 TM fusions on a total of 126 thumbs on 114 patients. The average age of the 79 women and 35 men was 57 at the time of the surgery; the youngest was 32, the oldest 77. The surgical techniques included fixing with or without wires, using supplemental bone grafts, and compression screws.

Before surgery, the patients were tested on their strengths for tip-to-tip pinch (called oppositional pinch). and grip strength, compared to their unaffected hand. The patients rated their pain scores on a scale from zero to 10, with zero being no pain and 10 being the worst possible. The average pain score was 6.6 before surgery. Range of motion, how many degrees, of the thumbs were measured as well.

After surgery, the patients were tested again and more x-rays were taken to check for fusion and if any arthritis had appeared in neighboring joints. The patients were also asked to rate how satisfied they were with the outcome. The researchers also evaluated complications, both during and after surgery.

The results of the study showed that 17 of the thumbs were "nonunions," which meant that the fusion didn't take. Eleven of the nonunion thumbs had bone grafting, six didn't. Nine of the patients with nonunions had another surgery - six for redo of the fusion and three for correction. In measuring the oppositional pinch and grip strengths, the researchers found improvement in both, as did the patients' report of pain. X-rays showed that arthritis did progress in neighboring joints in 39 cases (the scaphotrapeziotrapezoid), but only eight had symptoms of the arthritis. The remaining were detected by x-ray. As well, 16 thumbs developed arthritis in the metacarpophalangeal joint, but the patients didn't have symptoms.

Complications included 11 patients who had infections with the wires, or loosing or movement of the hardware. Six thumbs had irritation along the nerve or inflammation of the nerve (neuritis). Three of the thumbs had to have surgery to remove the hardware because of the increased pain. As well, two patients who had increased pain after surgery were diagnosed with complex regional pain syndrome or a similar syndrome.

The authors pointed out that fusion limits use and function of the joint, although it is usually a preferred treatment for the chosen patient groups. The complication rate was low as was the nonunion rate. Considering that the majority of patients appeared to be satisfied following the fusion surgery, pain was reduced, and function was improved, fusion for this type of arthritis does improve the long-term patient outcome.
Marco Rizzo, MD, Steven L. Moran, MD, and Alexander Y. Shin, MD. Long-Term Outcomes of Trapeziometacarpal Arthrodesis in the Management of Trapeziometacarpal Arthritis. In Journal of Hand Surgery. January 2009. Vol. 34A. Pp. 20 to 26.