The thumb carpometacarpal (CMC) joint is prone to instability and arthritis. Surgical treatment options include ligament reconstruction techniques with or without trapezium excision, implant arthroplasty, and arthrodesis. CMC arthrodesis has traditionally required prolonged immobilization because of high nonunion rates. Consequently, range of motion expectations have been pessimistic due casting induced stiffness superimposed upon obligatory CMC motion loss with various fixation techniques. Conceptually, rigid internal fixation should allow early range of motion and improve functional outcome without compromising union rates.

Purpose; this study evaluates the outcome of patients treated with thumb CMC arthrodesis using minicondylar bladeplate fixation and distal radius bone grafting.

Technique; approaching dorsally, joint surfaces are contoured reciprocally to cancellous bone and supplemented with distal radius bone graft. Rigid fixation is achieved with a 2.7 mm minicondylar bladeplate (Synthes). The same surgeon followed consistent technique in all cases. Aftercare included cast immobilization for 4 - 6 weeks with progression to a removable splint for interval active range of motion exercises. Splinting is discontinued upon radiographic confirmation of union.

Materials and methods; Over 9 years 47 patients had 58 arthrodeses (11 bilateral). Five patients had less than one-year follow up. Another 5 could not be recalled. Forty patients with 48 arthrodesis were evaluated retrospectively with an average follow up of 55.4 months (4.6 years), range 12 – 109 months (1 – 9 years). The average age was 49 years (range 28-65). Subjective evaluation included pain and function, including during common activities of daily living before and after surgery. Objective data was collected including range of motion, grip and pinch strength and dexterity assessment.

Results; Postoperative grip averaged 59.8 kg. vs. 66.7, key pinch strength 12.9 kg. vs. 14.0, tip pinch 12.1 kg vs. 12.5., radial abduction 45 degrees vs. 55, palmar abduction 46 degrees vs. 56 on the opposite side respectively. Composite thumb flexion lacked an average 1.2 cm (range 0-5cm) from thumb tip to the small finger palmar digital crease. Two patients (3.8% of arthrodeses) have gone on to nonunion; one had the site regrafted with successful union and the other is functioning with a fibrous nonunion. Patients were generally satisfied with pain relief, function, return to work and avocational activities.

Conclusion; CMC arthrodesis using minicondylar bladeplate fixation and bone grafting provides rigid fixation and allows earlier range of motion exercises without compromising union rates compared to published series. Patients reported satisfactory pain relief and functional outcome.