Accuracy of injection into the basal joint of the thumb.

To investigate the accuracy of intra-articular injection of the basal joint and to determine the rate of soft-tissue extravasation of injected material in successful intra-articular injection, we injected the basal joint of 30 hands with radiopaque dye (with fluoroscopy guiding needle placement in 8 cases) and then used fluoroscopy to check injection accuracy. Results were recorded depending on the location of the injected dye on fluoroscopic examination. Rates of intra-articular accuracy and soft-tissue extravasation for successful intra-articular injections were 100% and 25% for the fluoroscopy-guided group and 81.8% and 25% for the "blind" group. This study's accuracy rate for intra-articular injection of the basal joint is comparable to the rates reported for injection of larger joints. There is a relatively high soft-tissue extravasation rate for successful intra-articular injection.