- 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.
Acute and late radial collateral ligament injuries of the thumb
Gamekeepers thumb: a prospective study of functional bracing.