Purpose: To quantify the magnitude of rotational correction possible when comparing a single forearm bone osteotomy and fixation with stepwise osteotomy and fixation of both bones in a cadaver model and to determine if the order in which the stepwise osteotomies are performed influences the amount of correction. Methods: Ten fresh-frozen cadaveric forearms were fixed to a frame positioned in the field of view of a motion-capture system. An experimental supination contracture was induced in full supination. Cadaver forearms were assigned randomly to group I (ulna osteotomy, rotation, plating) or group II (radius osteotomy, rotation, plating). Cadavers in group I were used later in group III (ulna + radius) by completing a radial osteotomy, rotation, and fixation in the forearms with the plated ulna. Similarly the specimens assigned to group II were used later in group IV (radius + ulna) by completing an ulna osteotomy, rotation, and fixation in the forearms with the plated radiuses. Measurements of forearm pronation were made after single-bone (groups I, II) and stepwise both-bone (groups III, IV) rotational osteotomies. Results: Stepwise rotational osteotomy and fixation of the ulna followed by the radius produced significantly more corrective pronation (101°) than rotating the radius followed by the ulna (65°). Rotating the radius gave only moderate correction (58°) and minimal correction was produced by ulna osteotomy alone (15°). Conclusions: Rotational osteotomy of both forearm bones can create approximately 100° of correction when performed at the proximal ulna followed by the distal radius. If less rotation is needed then the distal radius osteotomy alone can provide approximately 60° of correction.