Notes

Outline

Gamekeeper’s Thumb, Mallet Finger, and Jersey Finger Dawn M. Mueller, M.S.P.A.S., PA-C Affinity Orthopaedics and Sports Medicine

Gamekeeper’s Thumb

Definition Acute instability of the ulnar collateral ligament (UCL) The most common soft tissue injury of the thumb Metacarpophalangeal (MP) joint is UCL sprain Also known as Skier’s Thumb

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Mechanism of Injury Rapid forceful abduction and extension of the MP joint Greater than 80% of complete tears occur distally After a complete tear, the adductor aponeurosis separates the proximal and distal stumps, preventing ligament healing without surgical intervention.  This is often termed a Stener lesion.

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Evaluation Radiographs **Before valgus stressing is done** Rule out/in avulsion fracture PA to help look for radial translation, dorsal capsule tears can lead to volar subluxation Swelling – specifically on ulnar aspect of MCP joint Palpation may reveal tender fullness or lump on ulnar MC head or neck (highly suggestive of Stener lesion)

Evaluation Valgus Stress Testing May need local anesthetic to get a good exam Stress in full extension (accessory ligament) and 30 degrees of flexion (UCL) Stabilize first MC to prevent rotation, apply valgus stress to MC joint 30 degrees of opening or 15 degrees more than the non-injured side is consistent with complete tear 35 degrees of opening in extension is consistent with tear of both the proper and accessory ligaments

Evaluation Check for an endpoint – if present it is highly unlikely that a complete tear has occurred Be sure to test non-injured thumb for comparison

Classification Grade I – Stretching of the ligament without instability (usually don’t seek medical attention) Grade II – Partial tear with pain and swelling but no instability (25% seek medical attention) Grade III – Compete tear with instability

Treatment If the joint is stable and UCL is at least partially intact, healing will occur without surgery Immobilize in short arm thumb spica cast or splint with IP joint free for 4 weeks Then begin flexion and extension exercises Wean splint or cast at 6 weeks Avoid stressful activities for 12 weeks For complete tears Operative Intervention If in doubt, explore the ligament

Complications Painful Pinch Turning door knobs Holding keys to start car Holding ski poles

Mallet Finger

Definition Traumatic avulsion of the DIP extensor tendon of the finger Most common extensor tendon injury Sometimes called baseball finger or drop finger Tendon may be stretched, completely torn, or associated with a bony avulsion

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Mechanism of Injury Caused by sudden flexion of the distal interphalangeal (DIP) joint while the finger is in an extended position Often occurs from a blow to the tip of an extended finger

Evaluation Dorsal DIP area is tender, painful, swollen, and red initially, but after 2 weeks the fingertip is usually no longer painful DIP joint is in flexion, and patient is unable to extend the joint.

Evaluation Radiographs-  AP and lateral views to evaluate for bony avulsion from the dorsal side of the distal phalanx, as well as volar subluxation of the distal phalanx caused by unopposed pull of the flexor tendons If avulsion fracture involves more than 25% of joint surface and/or the fracture is displaced Refer to orthopaedics immediately

Treatment For most patients, treatment consists of extension splinting of the DIP joint; full time for 6 weeks, followed by nighttime splinting for 6 more weeks Dorsal aluminum splint or stack splint Patient compliance is necessary - if the tip of the finger droops at any time after splinting begins, the splinting period starts over Weekly follow up visits to monitor progress usually lead to better outcome (especially if concerned about compliance)

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Treatment After 6 weeks of continuous splinting, may begin guarded active flexion if no extensor lag is evident Noncompliant patients, or those in occupations in which continuous splinting is difficult may be better treated surgically

Surgical Treatment Surgical evaluation should be sought for patients with an unstable joint, an avulsion fracture involving greater than 25% of the joint surface, or with compliance issues Surgical treatment consists of wire fixation Surgical reconstruction may be needed for injuries more than 6 weeks old which lead to significant functional loss to the patient.

Complications Left untreated, persistent flexion deformity or a swan-neck deformity is possible Allowing PIP flexion while splinting is important to help prevent this Even with treatment, some flexion deformity may persist.

Jersey Finger

Definition Traumatic avulsion of the flexor digitorum profundis (FDP) tendon The ring finger is most commonly affected

Mechanism of Injury DIP hyperextension (i.e. “jammed finger”) Similar to Mallet finger injury – outcome dependant on whether flexion or hyperextension injury occurred Most commonly occurs in football when grabbing the jersey of an opponent who is pulling away

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Evaluation Tenderness on the volar aspect of the DIP joint A bony avulsion may be palpable, and can be evaluated with radiographs Patient is unable to flex the DIP joint with the proximal interphalangeal (PIP) joint held in extension.  This eliminates the action of the flexor digitorum superficialis (FDS) and isolates the action of the FDP

Treatment The avulsed tendon will eventually retract proximally into its sheath; therefore treatment is surgical repair All complete tears must be fixed Early recognition is important Late injuries may require tendon-grafting procedures

Review

Review Terms Gamekeepers Thumb Skiers Thumb Mallet Finger Jersey Finger

Important Info to Remember Determine which joint is affected Is the pain/injury volar or dorsal? What causes the pain? Get X-rays

References Green, DP, MD, Hotchkiss, RN, MD, Pederson, WC, MD.  Green’s Operative Hand Surgery.  4th Edition.  Chuchill Livingstone.  1999. Heyman, Philip, MD.  Injuries to the Ulnar Collateral Ligament of the Thumb Metacarpophalangeal Joint.  JAAOS, July/Aug 1997 Mercier, LR.  Practical Orthopedics. 5th Edition.  Mosby, Inc.  2000. Miller, MD, MD.  Review of Orthopaedics.  2nd Edition.  W. B. Saunders Co.  1996.

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