Bennett's Fx ICD-9
- 815.01 (closed fracture base of thumb metacarpal)
- 815.11 (open fracture base of thumb metacarpal)
- 815.00 (closed metacarpal fracture; unspecified)
Bennett's Fx Etiology / Epidemiology / Natural History
- Intra-articular avulsion fracture of the volar-oblique ligament of the the thumb CMC joint.
Bennett's Fx Anatomy
- Abductor pollicis longus and adductor pollicis displace the metacarpal radially and proximally.
- Anterior oblique ligament remains attached to fracture fragment.
- Bennett fragment is the volar-ulnar aspect of the metacarpal base.
Bennett's Fx Clinical Evaluation
- Pain, swelling, ecchymosis at the thumb MC base.
- Document neurovascular exam.
Bennett's Fx Xray / Diagnositc Tests
- P/A, lateral and oblique views of the thumb.
- True lateral view: palmar surface of the hand is placed flat on cassette; hand and wrist are pronated 15°-35° . Tube directed obliquely 15°distal-to-proximal, centered over the trapeziometacarpal joint (Billing L, Acta Radiol1952; 38:471).
Bennett's Fx Classification / Treatment
- Bennett fragment < 20% of the articular surface: CRPP. Drill K-wire obliquely across the thumb the trapeziometacarpal joint while the the fracture is reduced by extending and pronating the metacarpal while longitudinal traction and downward pressure are applied to the metacarpal base.
- Bennett fragment>20% of the articular surface:ORIF. Wagner incision between the abductor pollicis longus and the thenar muscles, extended proximally and radially to the radial border of the flexor carpi radialis. Reflect thenar muscles subperiosteally, incise joint capsule. Debride hematoma from fx site. Reduce fx. Fix with 2.0- or 2.7-mm lag screw.
- >1mm malunion=arthritis
Bennett's Fx Associated Injuries / Differential Diagnosis
Bennett's Fx Complications
- Stiffness / Contracture
- Painful hardware
Bennett's Fx Follow-up Care
- Post-op: Thumb spica splint, elevation, NWB
- 7-10 Days: Wound check, Thumb spica cast
- 6 Weeks: K-wire removal, begin ROM exercises provided union is evident on xray.
- 3 Months: Evaluated ROM. Sport specific rehab.
- 6 Months:
- 1Yr: f/u xrays, Assess outcome.
Bennett's Fx Review References