Predisposing factors contributing to the development of first carpometacarpal (CMC) osteoarthritis include an inherent laxity or incongruency of this joint, a shallow trapezium saddle, and heavy stresses placed on the joint with pinching and grasping. Splinting is a common mode of conservative treatment for CMC osteoarthritis. This study assessed the objective and subjective responses of patients with CMC osteoarthritis who wore short and long opponens splints, as well as radiographic changes associated with wearing of the splints. The study evaluated 26 hands. Each patient was assigned at random to wear the long or the short splint first. Patients wore the splints for one week. They then documented function in their splints (on 22 activities of daily living) and rated splint satisfaction and pain levels on visual analog scales. One week after application of the first splint, the second splint was applied and worn for one week, and all measures were repeated. On the final visit, tip pinches were evaluated and x-rays were taken to assess subluxation. One-way repeated-measure analysis and paired comparison were used to analyze the pinch, pain, radiographic, and splint-rating measures. Descriptive statistics were used to assess activity-of-daily-living function and splint preference. Both splints appear to reduce subluxation at the first CMC joint in patients with grades 1 and 2 osteoarthritis. The majority of the patients picked the short splint when asked at the end of the study which splint they preferred. The splints do not appear to increase pinch strength or affect pain levels associated with the performance of pinch strength measurements. This study supports anecdotal evidence that patients with CMC osteoarthritis get pain relief with splinting.