The thumb carpometacarpal joint is the most common site of osteoarthritis in the hand with post-menopausal female predominance, and it can be associated with trapezial dysplasia. For treatment of osteoarthritis the use of the Arpe TM prosthesis has proven to be a useful and reliable option with a remarkable long-term survivorship and a high patient satisfaction. However, several initially undiagnosed concomitant or secondarily occurred disorders at the thumb may have negative influence on the outcome, and it can lead to a false diagnosis "failed total thumb carpometacarpal joint replacement". In the presence of trapezial dysplasia, an exact preoperative planning is absolutely necessary to avoid postoperative dislocation of the implant.