Muscle-sparing dorsal approach for Bennett fracture osteosynthesis

Fractures of the first metacarpal base with partial involvement of the joint surface, known as Bennett fractures, are unstable due to static and dynamic forces. If closed reduction remains unsuccessful, an open procedure is indicated. The fracture is usually exposed via a radiopalmar approach according to Wagner to the trapeziometacarpal (TMC) joint with detachment of the thenar muscles. An alternative,muscle-sparing dorsal approach to the TMC joint and its long-term results in the treatment of Bennett fractures are described.

Over a period of 15 years, a total of 53 patients with Bennett fractures were reduced via a dorsal approach and fixed with screw osteosynthesis. In a follow-up examination, the mobility and the strength development of the hand were compared with the healthy contralateral side. Subjective symptoms were assessed using the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and the German Thumb Disability Examination (TDX-G) questionnaire.

8.2 years (±4.6; 2.2-16.7) after the accident, 33 patients (35.6 years ±16.5) were available for follow-up examination. Radial and palmar abduction were significantly reduced by 5% and 6%, respectively. No other significant measurable differences were found. The DASH score and TDX-G score were 4.6 and 5.7, respectively. A total of 4 complications occurred.

The dorsal, muscle-sparing approach to the TMC joint is an alternative to the radiopalmar approach for the treatment of Bennett fractures. In the long term, patients are little restricted in their everyday lives despite significant measurable restrictions in movement.