Background:Thumb function is integral to hand movement and overall hand function. Impairment, often caused by carpometacarpal (CMC) arthritis, reduces the quality of life. Here, we explored a novel approach using a mixture of the stromal vascular fraction, adipose-derived stem cells, and platelet-rich plasma to treat symptomatic trapeziometacarpal osteoarthritis.Methods:Retrospective data from 30 hands of 19 patients classified as Eaton and Littler stages 1-4 were analyzed. Platelet-rich plasma and fat were collected under sterile conditions, followed by centrifugation, stem cell extraction, and injection of the mixture into the thumb CMC joint under x-ray guidance. The measurement parameters included the visual analog scale pain score, grip strength, pinch strength, and Thumb Disability Examination (TDX) score. Statistical analysis was performed using paired t tests to evaluate the outcomes across the entire group, individual stages, and early/late stages.Results:We examined 30 hands of 19 patients with trapeziometacarpal osteoarthritis. Pain reduction was significant at 6 and 24 months for all stages, particularly stages 2 and 3. Substantial pain reduction was also observed at the early and late stages. The TDX score decreased significantly in all groups after 6 and 24 months. Hand function notably improved with significant gains in tip-to-tip pinch strength at 24 months and palmar pinch strength at 6 and 24 months. No complications were observed.Conclusions:The intra-articular injection of autologous conditioned plasma/stromal vascular fraction in patients with thumb CMC arthritis, in all stages, helps to improve pain symptoms and postpone potential resection arthroplasty with minimal surgical intervention and risks.