De Quervain's tenosynovitis is a common cause of radial sided wrist pain and is described as an entrapment tendinitis of the tendons in the first extensor compartment. Physiotherapy and splinting are initial conservative treatment. Steroid injections are an effective treatment modality but may fail due to the anatomical variation in the first dorsal compartment of the wrist. We present a 39-year-old female who failed conservative treatment. She received a steroid injection, but symptoms resolved for 6 months only. We proceeded to surgery and noted three subcompartments consisting of one for the extensor pollicis brevis and two for the abductor pollicis longusas opposed to one extensor compartment. The steroid injection may have failed to infiltrate all the subcompartments resulting in treatment failure. General practitioners and surgeons must be aware of this variation if there are to provide effective treatment. Ultrasonographic guidance may be required for steroid injections in recalcitrant de Quervain's disease.