Basal joint osteoarthritis of the thumb: a prospective trial of steroid injection and splinting.

PURPOSE There have been few prospective studies evaluating the results of nonsurgical treatment of a well-defined patient cohort with symptomatic basal joint osteoarthritis of the thumb. This prospective study uses a validated outcome instrument to examine the effectiveness of a single steroid injection and 3 weeks of splinting in patients with osteoarthritis in Eaton stages 1 to 4 with a minimum of 18 months of follow-up evaluation. METHODS Thirty consecutive patients (30 thumbs) were studied prospectively to evaluate the efficacy of a single injection of corticosteroid into the trapeziometacarpal joint, followed by immobilization in a thumb spica splint for 3 weeks. All patients answered an outcome-based questionnaire (Disabilities of the Arm, Shoulder, and Hand) and were examined before injection, 6 weeks after injection, and at final follow-up examination (minimum, 18 months). Eaton radiographic stage was recorded by 3 independent observers. RESULTS At 6 weeks 13 patients had improvement in pain intensity and 17 patients reported no symptomatic improvement. Twelve of those with relief at 6 weeks continued to have relief at long term follow-up evaluation (mean, 25 months). Of patients with long-term relief average grip strength of the affected thumb was 95% of contralateral side, whereas those without relief had grip strength values that were 60% of contralateral side. For those patients without relief at 6 weeks there was no improvement seen at later follow-up evaluation. Five patients with Eaton stage 1 disease had an average of 23 months of relief with nonsurgical treatment. In stage 2 and stage 3 disease 7 thumbs improved at 6 weeks after injection and 6 thumbs had long-term relief. In stage 4 disease, 6 thumbs had neither short-term nor long-term relief with the injection. Disease side, handedness, and smoking did not affect outcomes. At final follow-up evaluation 12 thumbs had had surgical treatment. CONCLUSIONS Steroid injection with splinting for the treatment of basal joint arthritis of the thumb provided reliable long-term relief in thumbs with Eaton stage 1 disease but provided long-term relief in only 7 of 17 thumbs with Eaton stage 2 and stage 3 basal joint arthritis.