Skier’s thumb is the same injury, but it occurs acutely when a skier falls on his or her ski pole. The damage is also seen acutely in volleyball and football players.

ANATOMY

The first metacarpophalangeal (MCP) joint is at the base of the thumb. The joint consists of the first metacarpal of the hand and the proximal phalanx of the thumb.The ulnar collateral ligament (UCL) provides stabilization of the first MCP joint. The UCL connects the metacarpal to the proximal phalanx of the thumb. There is a proper ligament of the UCL and an accessory ligament.

The adductor pollicis muscle also contributes to the stability of the MCP or thumb joint. The muscle expands to form the adductor aponeurosis, which lies superficial to the UCL. An aponeurosis is a sheet of fibrous connective tissue that extends from a muscle.

INJURY

A gamekeeper’s or skier’s thumb consists of a partial or complete tear of the UCL. Such disruption can occur over time (gamekeepers) or suddenly (skiers).An acute injury happens from a sudden abduction (lateral) stress of the thumb happens as when falling on an outstretched hand. The UCL may be partial torn or completely ruptured.2 An avulsion fracture of the proximal phalanx or, less commonly, the metacarpal bone may be present.

A Stener injury happens when there is a complete rupture of the UCL, and the ends of the ligament retract. The adductor aponeurosis separates the two ends of the torn UCL, so healing of the UCL is not possible. A Stener injury is frequently associated with an avulsion fracture of the proximal phalanx.3

DIAGNOSIS

The diagnosis is made by the history and physical exam. There is pain, swelling, and bruising at the base of the thumb. Weakness and worsening pain occur when the patient tries to grasp an object.4On exam, a mass palpated on the little finger side of the MCP joint may represent a ruptured UCL. X-rays will first be performed looking for a displaced avulsion fracture. If a displaced avulsion fracture exists, stress testing is not done for fear of worsening the displacement of the avulsed bone fragment.5

If there is not a displaced fracture, stress testing will be done. The thumb, metacarpal area is stabilized with one hand. Lateral stress is applied in both thumb flexion and extension positions. If there is laxity of more than 35 degrees or if there are 15 degrees more laxity compared to the unaffected thumb, there is probable UCL rupture. Lateral laxity of the MCP joint in both flexion and extension positions is strongly correlated with UCL tearing and Stener injury.6

An avulsion fracture that is displaced one-fourth or more of the MCP surface requires surgery, and no stress testing will be done. An MRI can be obtained revealing soft-tissue  damage.7

CLASSIFICATION

Type I, type III, and type V can be treated without surgery by placing the

hand in a short arm thumb spica cast or splint for 4 to 6 weeks.

Type II, type IV, and type VI needs surgical intervention.

Basically, partial tears of the UCL and non-displaced avulsion fractures can be successfully treated with a cast or splint.8Complete tears of the UCL, with or without a Stener injury, and displaced fractures require surgery.

SURGERY

A one-inch  incisionis made along the little finger side of the thumb-MCP joint. A displaced fracture may require a pin to be fixed. The UCL is repaired with a suture anchor. If the UCL is irreversibly damaged, a tendon graft may be used to replace it.9After surgery, the patient will wear a short arm thumb spica cast for 4 weeks. The cast and any pins placed during surgery are removed after 4 weeks. A splint is applied that immobilizes the MCP-thumb joint for 2 more weeks. The splint can be removed to allow range of motion exercises of the MCP-thumb joint by the physical therapist. In 3 to 4 months, unrestricted use of the thumb is possible, and the patient may return to their sport.10

COMPLICATIONS

If the gamekeeper’s thumb is not repaired, there will be chronic instability of the thumb. Grasping objects will be weak, and there will be decreased dexterity of fine pincher-type movements. Pincher-type movements are when the thumb moves to touch the ring finger (4th finger), so holding a key would be difficult. Most likely, arthritis will form in the joint further causing disability of the thumb.Most complications occur when treatment is not obtained, or a missed diagnosis happens. When properly treated, 95 percent of patients will regain normal use of their thumb.11

REFERENCES

1. Campbell C. “Gamekeeper’s Thumb.” J Bone Joint Surg Br, 37-B (1):148-149, 1955.
2. Peterson J, Bancroft L. “Injuries of the Fingers and Thumb in the Athlete.” Clin Sports Med, 25(3):527-542, 2006.
3. Stener B. “Displacement of the Ruptured Ulna Collateral Ligament of the Metacarpophalangeal Joint.” J Bone Joint Surg Am, 44B (4):869-879, 1962.
4. Newland C. “Gamekeeper’s Thumb.” Clin Sports Med, 25(3): 41-48, 1992.
5. Ibid.
6. Fricker R, Hintermann B. “Skier’s Thumb: Treatment, Prevention, and Recommendations.” Sports Med, 19(1): 73-79, 1995.
7. Plancher K, et al. “Role of MR Imaging in the Management of “Skier’s Thumb” Injuries.” MagnReson Imaging Clin N Am, 7(1): 73-84, 1999.
8. Chuter G, Muwanda C. “Ulnar Collateral Ligament Injuries of the Thumb: 10 Years of Surgical Experience.” Injury, 40(6): 652-656, 2009.
9. Demirel M, Turhan E, Dereboy F, et al. “Surgical Treatment of Skier’s Thumb Injuries: Case Report and Review of the Literature.”Mt Sinai J Med, 73(5): 818-821, 2006.
10. Ibid.
11. Ibid.