CASE 1984 Published on 03.03.2003

Bennett's fracture

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

E. Aldlyami , N. Taha , R. Jose

Patient

25 years, male

Clinical History
The patient presented after a fall onto his outstretched hand. Clinically he had tenderness with reduced flexion, extension, abduction and adduction of the thumb.
Imaging Findings
The patient presented after a fall onto his outstretched hand. Clinically he had swelling and tenderness in the anatomical snuffbox with reduced flexion, extension, abduction and adduction of the thumb. Radiographs of the wrist showed intraarticular fracture through the base of the first metacarpal.
Discussion
Edward H.Bennett, an Irish surgeon, described Bennett's Fracture in 1881.It is an intraarticular fracture through the base of the first metacarpal.The shaft is laterally dislocated by the unopposed pull of the abductor pollicis longus,but the medial projection remains in place or slightly rotated because of its capsular attachment.Bennett's fracture is uncommon and the injury occurs when the thumb metacarpal is axially loaded and partialy flexed.The volar lip fragment is of variable size, byramidial in shape, and consist of the volar-ulnar aspect of the metacarpal base.The anterior oblique ligament,which runs from the volar lip to the trapezium, holds the fragment in anatomic position.The remaining metacarpal base sublaxates radially, proximally, and dorsally. Accurate Radiographs are important in establishing congruity of the carpometacarpal joint, the technique necessary to get a true lateral view of the joint. The palmar surface of the forearm and hand are placed flat on the cassette, and the hand and wrist are then pronated 15 to 35 degrees with thumb remaining in contact with the cassette. The roentgen tube is directed obliquely 15 degrees distal to proximal, centering over the trapeziometacarpal joint. There are two options for management of Bennett's fracture:
  1. Conservative management through the thumb being immobilised in radial abduction in plaster of Paris for 6 weeks. However, the most usual clinical outcome in patients treated conservatively is a decreased range of movement and grip strength.
  2. Operatively, the most common method is closed reduction of the fracture dislocation with percutaneous K wire fixation or open reduction with osteosynthesis for delayed cases. Exact reduction, by either the open or closed method, should be the aim of treatment of Bennett's fracture.
The most common complications of Bennett's fracture are Malunion which may result in recurrent or persistent sublaxation of the trapeziometacarpal joint, and arthritis which is a common late complication.
Differential Diagnosis List
Bennett's fracture
Final Diagnosis
Bennett's fracture
Case information
URL: https://www.eurorad.org/case/1984
DOI: 10.1594/EURORAD/CASE.1984
ISSN: 1563-4086