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Gamekeeper’s Thumb

- See:
      - Pediatric Game Keeper's Thumb
      - Thumb Deformities in RA
      - Rheumatoid Gamekeeper's Thumb
      - Thumb MP Joint Dislocation

- Discussion:
    - involves injury to ulnar collateral ligament of thumb MCP joint, causing instability at that joint;
    - the orignal description refered to a chronic injury brought on by chronic stretch of the ulnar collateral ligament;
    - ulnar collateral ligament nearly always separates from the base of first phalanx of the thumb;
              - it frequently becomes lodged between adductor pollicis aponeurosis and its its normal position (Stener Lesion);
    - a spectrum of ulnar instability may exist, depending on whether there is additional injury to the adductor aponeurosis, and volar plate;
    - Stener Lesion:
              - occurs when torn distal edge of collateral ligament displaces superficial and proximal to the to adductor aponeurosis;
                     - proximal margin of aponeurosis slides distal to insertion of ligament;
              - creation of Stener lesion requires significant radial deviation of phalanx (? up to 60 deg) along w/ combined tears of the proper and
                     accessory collateral ligaments inorder for the ligament to be displaced above the adductor aponeurosis;
              - ruptured end of ligament is no longer in contact w/ its area of insertion of the phalanx, & therefore healing can not occur;
              - reference:
                     Displacement of the ruptured ulnar collateral ligament of the metacarpo-phalangeal joint of the thumb
    - Gamekeeper's Fracture:
         - even slightly displaced Gamekeeper's fractures tend to do well with immobilization;
         - in the study by Kuz JE, et al (1999), 30 patients w/ gamekeeper's fracture were treated nonoperatively;
               - none of these 30 patients were dissatisfied with the outcome;
               - 3 patients showed instability on stress testing;
               - there was a 25% nonunion rate;
               - patients with residual symptoms tended to have larger bone fragments with greater initial rotation;
         - conservative indications for surgery include: frxs with more than 30% of the joint surface, and significant displacement/malrotation;
         - avoid stress testing of these fractures since it can lead to fracture displacement;
         - references:
               - Outcome of avulsion fractures of the ulnar base of the proximal phalanx of the thumb treated nonsurgically.
               - Bony skier's thumb injuries.   
               - Grade III avulsion fracture repair on the UCL of the proximal joint of the thumb
               - Skier's thumb - the significance of bony injuries.  


    - anatomy and function:
          - MP joint is capable of adduction and abduction as well as flexion and extension;
          - ulnar stability is provided by static and dynamic restraits:
                 - static restraints: proper collateral ligament, accessory collateral ligament, volar plate, and dorsal capsule;
                 - dynamic restraints: adductor pollicis;
          - proper collateral ligament:
                 - runs from metacarpal head to volar aspect of proximal phalanx;
                 - proper collateral ligament tightens in flexion and relaxes in extension;
          - accessory collateral ligament:
                 - accessory ligament lies palmar to the proper ligament and insets inserts onto the volar plate (it is contiguous w/ the proper ligament);
                 - accessory ligament tightens in extension and loosens in flexion;
          - adductor mechanism:
                 - adductor pollicis has superficial insertion into the the extensor mechanism of the thumb (which cover the dorsal capsule and ulnar collateral ligament), and a deep insertion into the proximal phalanx;
          - ref: Ligamentous structures of the metacarpophalangeal joint: a quantitative anatomic study.
    - associatted lesions:
          - in addition to injury of the proper collateral ligament, there may be injury to the accessory collateral ligament, dorsal capsule, volar plate, occassionally adductor insertion, proximal phalanx fractures;

- Exam:
    - exam should begin w/ normal uninjured thumb;
          - note the stability of the uninjured MPJ joint as well as its ROM;
    - look for a supination deformity of the joint (which may be associated w/ palmar subluxation of the joint);
    - stability:
          - this is generally performed in conjunction w/ x-rays;
          - local anesthetic block is required for patient comfort;
          - gamekeeper's frx is a contra-indication to stress testing (but stress testing can procede with non displaced avulsion fractures);
          - stability is documented w/ stress radiographs;
    - palpation:
          - determine point of maximum tenderness, noting that generally the ligament tears distally off the proximal phalanx;
          - palpation of torn ligament ends may identify displaced collateral rupture (ie, Stener lesion);
    - ref: Injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint. Biomechanical and prospective clinical studies on the usefulness of valgus stress testing.

- Radiographs: for Game Keeper's Thumb
    - instability is indicated w/ radial deviation greater than 40 deg in extension and deviation greater than 20 deg in flexion;
    - instability in both flexion and extension may indicate tears of both the proper and accessory collateral ligaments (often associated w/ Stener lesion);
    - more than 3 mm of volar subluxation of the proximal phalanx also indicates gross instability;

- Non Operative Rx:
    - treat with a short arm cast with a thumb spica;
    - complications of non operative treatment:
             - main complication is failure of ligament to heal & resulting in instability of joint;
             - gross instability is usually caused by Stener's lesion;
    - references:
             - Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament of the thumb. A prospective randomized study of 63 cases.
             - Gamekeepers thumb: a prospective study of functional bracing.

- Surgical Treatment:
    - indications for surgery:
         - gross radiographic instability (which usually represents tears of both the proper and the accessory collateral ligaments);
         - presence of palpable torn ligament ends (Stener lesion);
                - note: w/ excessive swelling the Stener's may not be palpable;
         - occassionally, significant ligamentous injury may occur w/o immediate gross instability due to swelling and muscle spasm;
                - consider re-examing patients at 5-7 days, and if motion has not been regained and if swelling has not improved consider surgical fixation;
    - Surgical Treatment (for injuries less than 2-3 weeks old);

- Chronic Game Keepers:
    - proximal phalanx tends to volarly subluxate and rotate;
    - deformity develops as a result of damage to ulnar collateral ligament and dorsal capsule;
            - in addition to dorsal joint support provided by capsule & EPB, EPL tendon also contributes to the dorsal stability of MP joint;
    - when ulnar collateral ligament ruptures, ulnar side of phalanx tends to displace volarly & rotate into supination;
    - w/ repeated radial stress, dorsal expansion may attenuate & allow EPL to shift ulnarly, compromising its extension effect on the joint;
    - mangement:
            - an MP joint w/ chronic instability and a small flexion arc should be considered for MP joint arthrodesis;
    - refs:
            - Ligament replacement for chronic instability of the ulnar collateral ligament of the metacarpophalangeal joint of the thumb. 
            - Grade III radial collateral ligament injuries of the thumb metacarpophalangeal joint: treatment by soft tissue advancement and bony reattachment.

Diagnosis of displaced ulnar collateral ligament of the metacarpophalangeal joint of the thumb.

Post-traumatic instability of the metacarpophalangeal joint of the thumb.

Instability of the metacarpophalangeal joint of the thumb.

Gamekeeper's thumb.

Acute and late radial collateral ligament injuries of the thumb

Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament of the thumb. A prospective randomized study of 63 cases.

Gamekeepers thumb: a prospective study of functional bracing.