Intra- Versus Extra-Articular Corticosteroid Injections for Carpometacarpal Arthritis of the Thumb
Zachary C. Hanson, MD1; Gary M. Lourie, MD2; D. David Davis, MD1
1Wellstar Atlanta Medical Center, Atlanta, GA; 2The Hand and Upper Extremity Center of Georgia, Atlanta, GA
Introduction: Carpometacarpal (CMC) osteoarthritis (OA) of the thumb is a commonly encountered in the clinical setting. Intra-articular corticosteroid injections are frequently included as part of the initial conservative treatment and are performed in the office setting using anatomic landmarks to guide needle placement. Accurate localization within the joint is technically challenging due to the small size of the CMC joint and distorted anatomy in the setting of OA; injection accuracy rates vary from 60% to 90% depending on the experience of the provider.
The purpose of this study was to determine whether the therapeutic effects of corticosteroid injections for CMC arthritis are dependent upon intra-articular administration. We hypothesize there is no significant difference in pain relief following intra-articular versus extra-articular CMC joint injections.
Methods: Patients with bilateral thumb CMC arthritis were included. Injections were performed by a single, hand fellowship-trained surgeon with over 30 years’ experience. Injections were performed in each thumb CMC joint (left and right) and noted at time of injection as being intra- or extra-articular, depending upon manual feedback and resistance met during the injection. Subjective improvement in pain and perceived improvements in function were recorded for each side at 1 week, 6-weeks and 3 months following injections.
Results: 24 patients were included. At 1 week, 22/24 (92%) of patients reported at least 80% reduction in pain in both thumbs, with 8/24 (33.3%) patients reported complete resolution of symptoms. 22 patients (92%) reported a subjective strength increase. These patients were unable to distinguish a subjective difference in pain relief between either thumb, regardless of whether an intra- or extra-articular injection was performed. At 6 weeks, 1 patient (4.2%) reported continued complete relief of pain. 16 (66.7%) had perceived improvement in strength. By 3 months, 1 patient (4.2%) had continued pain relief and perceived improvement in strength. 1 patient had no relief at any time point in either hand.
Conclusions: Corticosteroid injections for CMC arthritis of the thumb improve pain and functional strength in the short term (weeks following injection) for most patients. Patients had the same perceived improvement in pain relief and functional strength regardless of whether the injection was intra- or extra-articular. The therapeutic benefits of corticosteroid injections do not appear to be contingent on accurate injection within the intra-articular space. The technical challenges of reliably locating the CMC joint space should not discourage practitioners from providing injections, as extra-articular injections may provide equivalent clinical benefits.
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