Trapeziometacarpal joint pain is often associated with a dynamic adduction deformity of the thumb metacarpal, combined with radial subluxation at the base of the thumb metacarpal, due to trapeziometacarpal dysplasia. Addition-subtraction osteotomy is a surgical option to correct the bony deformity when conservative treatment fails. Eight patients who underwent surgery with this technique were prospectively evaluated. All patients were female and mean age was 42 (range 27-59) years. Mean follow-up period was 23 (range 10-42) months postoperatively. Seven patients (87.5%) were very satisfied. Joint mobility and strength of the operated thumb was restored to a degree comparable to the contralateral thumb. Overall function according to the Quick-DASH score improved by 75.5% and pain according to the Visual Analogue Scale decreased by 65%. Radiological evaluation showed a decrease of the trapezial slope. Mean angle between the articular surface of the trapezium and the long axis of the second metacarpal measured 1420 preoperatively 1290 and postoperatively. In the present study results of addition-subtraction osteotomy without ligamentoplasty were promising, especially for function and pain. The technique may be a valuable treatment option for trapeziometacarpal dysplasia with metacarpal instability.