Dorsal view left hand
Thumb Gamekeepers
Thumb Gamekeepers / Skiers Injury
Volar view left hand
Thumb Metacarpal-phalangeal Joint Injury
Thumb Metacarpal-phalangeal joint injury usually result from thumb hyperextended with a forced abduction force, commonly during a skiing injury. Chronic over distension may also occur as with an occupational hazard, as classically described as Gamekeepers thumb injury.
Thumb MCP joint extended with hyperabduction
Injury Mechanism:
- Direct force to thumb metacarpal-phalangeal (MCP) joint with thumb in extension with forced abduction
- Associated injuries include: Intra-articular thumb basal fractures of proximal phalanx and Steiner lesion (the Ulnar collateral ligament is displaced dorsally over adductor aponeurosis)
- Chronic laxity may result from overstretching of the Ulnar collateral ligament (UCL) as classically describe with Gamekeepers in Britain. The occupational overstraining of the MCP results in overstretching and associated instability of the MCP joint.
Causes:
- Acute injury as seen with skiing
- Overuse injury in occupations requiring twisting abduction thumb movements as in the historic Gamekeepers injured thumb
Presentation:
- Pain in thumb at MCP joint area at the side of UCL
- Deformity
Clinically:
- Tenderness at UCL area of the MCP joint
- Deformity
- Palpable mass (UCL retracted)
- Valgus stress testing of UCL demonstrating instability
Stress testing MC-P1 joint:
> 15° compared to the contralateral uninjured side indicates instability
Thumb Metacarpal Phalanx Joint Injury Classification
| Grade I | No laxity |
| Grade II | Mild laxity with end point |
| Grade III | Laxity with no end point |
| Hinterman Classification | |
| Type I | Non-displaced, stable in flexion (< 35o stress test) |
| Type II | Displaced fracture |
| Type III | No fracture, stable in flexion (< 35o stress test) |
| Type IV | No fracture, , unstable in flexion (< 35o stress test) |
| Type V | Avulsion fracture of Volar plate, stable in flexion |
| Type VI | Fragmentation of volar ulnar portion of P1 with associated injury of the UCL |
Radiology:
X-ray
- Robert view: Thumb AP (true AP of thumb: forearm in maximum probation with thumb dorsum against cassette) and lateral views (hand pronated 30° with radiographic beam angled 15° distally)
CT
- Ideal to view intraarticular fractures and surgical planning
Management
Non operative
Indications:
- Acute, nondisplaced grade Ⅰ/Ⅱ can me managed in thumb spica
Bracing/cast immobilization until union - Union 4-6 weeks
Surgery
Indications:
- Open fractures
- Acute unstable grade Ⅲ (> 35° MCP joint angulation or >15° compared to contralateral side on stress testing)
- Steiner lesion (usually associated with grade Ⅲ tears
- Displaced avulsion tears
- >25% articular fracture
Surgical fixation options:
- Open fractures
- Acute tear: repair ± anchors
- Chronic tears: UCL reconstruction
Thumb spica POP
Repair
Surgery Technique
Surgery Approach to MCP joint
Dorsoulnar approach:
Incision: 1cm proximal to MCP joint extended in a palmar direction around the ulnar aspect of the joint.
Overlying the ulnar collateral ligament include adductor pollicis aponeurosis & dorsal sensory branch of Radial nerve. Retract nerve & divide adductor pollicis aponeurosis overlying the UCL.
Surgery Repair UCL
Repair UCL with anchor. Alternatively pass suture fixation to ligament through drill holes of P1 and tie on opposite bone end.
Rehabilitation
- Conservative management: thumb splint until union 4-6 weeks
- Post surgery: Thumb splint until soft tissue swelling reduced, then custom made splint for 4-6 weeks
- Strengthening hand exercises after union
Active wrist ROM after 2 weeks
Finger adduction strengthening
Finger abduction strengthening
Hand grip strengthening
Download ASSIC Performance Fingerprint or Strength & Conditioning apps for rehab guideline routines or create own under professional supervision
References
- Gamekeepers thumb. SJ Rhee, C Cobiella. Trauma 2007;9: 163-170.
- Gamekeepers thumb. CY Hung, M Varacallo, KV Chang. StatPearls (Internet). Treasure Island (FL): StatPearls Publishing;2021 Jan.
- Skier’s thumb-the significance of bony injuries. B Hintermann, PJ Holzach, M Schutz. Am J Sports Med 21: 800-04.
