eMedicine Specialties > Orthopedic Surgery > Hand & Upper Extremity

Stener Lesion

Author: Joseph Rectenwald, MD, Staff Physician, Department of Orthopedic Surgery, Palmetto Richland Memorial Hospital
Coauthor(s): John J Walsh IV, MD, Associate Professor, Department of Orthopedic Surgery, University of South Carolina School of Medicine
Contributor Information and Disclosures

Updated: Mar 3, 2009

Introduction

In his now classic 1962 article, Bertil Stener described a distinct, surgically correctable anatomic lesion that could account for the chronic instability found in the thumbs of some gamekeepers and skiers.¹ CS Campbell first coined the term gamekeeper's thumb in 1955, when he described insufficiency in the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal (MCP) joint in many Scottish gamekeepers.²

The proposed etiology of this laxity was related to the method used by gamekeepers to kill wounded rabbits. A gamekeeper would hold the rabbit's legs in one hand and wedge the animal's neck in the cleft between the thumb and index finger of the other hand. By forcefully pulling on the rabbit's legs, the neck was stretched and extended against the ulnar side of the thumb, thus breaking the neck and killing the rabbit. The multiple repetition of this maneuver was thought to be the etiology of the ulnar collateral ligamentous laxity found in 20 of the 24 Scottish gamekeepers examined in Campbell's study.

More than a decade earlier, acute rupture of the UCL of the thumb as a result of major trauma was reported in Europe. European authors made the correlation between downhill skiing and this injury, coining the term skier's thumb. The proposed mechanism of injury was a traumatic avulsion of the UCL from forced abduction of the thumb proximal phalanx. Forced thumb abduction occurred from falling on the outstretched hand while still holding a ski pole. Any extreme valgus stress on the thumb can result in a ligamentous disruption of the UCL (see image below). The most common mechanism is a fall on the abducted thumb.

Stener observed and reported several cases in which a distal rupture of the UCL of the thumb MCP joint occurred, with interposition of the adductor aponeurosis between the distal site of attachment of the ruptured ligament and the detached ligament. The interposed adductor aponeurosis maintains separation between the ruptured ends of the ligament and thus prevents ligamentous healing and restoration of joint stability.

Problem

See Pathophysiology.

Pathophysiology

Stener described a lesion produced by forced thumb abduction in which the distal attachment of the UCL was traumatically avulsed from the proximal phalanx of the thumb.

The severed end would become caught under the adductor aponeurosis and therefore be unable to return to its anatomic position. Consequently, the severed ligament would fold on itself and thus be prevented from healing and restoring stability to the MCP joint (see image below).

Presentation

A patient with an acute injury to the ulnar collateral ligament (UCL) presents with a painful, swollen, ecchymotic thumb metacarpophalangeal (MCP) joint. The physician must differentiate between an incomplete rupture or sprain and a complete rupture of the UCL. If a complete rupture is suspected, the physician must differentiate between a complete rupture with adductor aponeurosis interposition (Stener lesion) and a complete rupture with anatomic or near-anatomic position of the severed end of the UCL.

Prior to the stress-testing part of the physical examination, plain anteroposterior (AP) and lateral radiographs are obtained. Valgus stress testing prior to radiographic evaluation may be contraindicated in the case of a nondisplaced ligamentous or avulsed bone fragment.³ Such a maneuver theoretically could turn a nondisplaced disruption into a displaced Stener-type lesion.

A protocol and classification system developed by Louis and colleagues⁴ (1986) provides for a systematic method of evaluation for the acute UCL injury. Radiographs are used to classify the ligamentous injury into 1 of 5 categories, as follows:

• Type I - This is a nondisplaced avulsion injury.
• Type II - This is a displaced fracture of the ulnar aspect of the base of the proximal phalanx. If no fracture fragment is seen on initial radiographs, assessment of MCP stability to passive radial deviation is attempted. The MCP should be in a flexed position for testing, with the examiner firmly grasping the metacarpal head with one hand and passively applying a radial force to the proximal phalanx with the other hand (see image below). If pain precludes examination, a local anesthetic may be used.
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    Stress view of ulnar collateral ligament.

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    Stress view of ulnar collateral ligament.

    
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• Type III - This is a ligament strain. If resistance is felt as the thumb is radially deviated less than 35°, the patient most likely has a type III ligament injury.
• Type IV - This is a complete UCL tear. The thumb deviates radially more than 35° as it is stressed. A type IV injury should be treated surgically, as it may reflect the presence of a Stener-type lesion.
• Type V - This is an avulsion of the volar plate, with no UCL injury. However, this type of trauma easily may be mistaken for a type II injury when it is associated with an avulsion fracture. A type V injury is stable in flexion and is treated with a thumb spica splint or cast for 4 weeks.

Palpation of a lump (the distal end of the ruptured UCL) on the ulnar aspect of the thumb MCP is highly suggestive of a Stener lesion. However, lack of a mass does not exclude a Stener lesion.

Other methods of diagnosis, such as stress radiography, magnetic resonance imaging (MRI),⁵ arthrography, and ultrasound scanning,⁶ also have been used to aid in diagnosing Stener lesions, with varying accuracy. Further research is needed to delineate the accuracy of these modalities.^7,8,9

Early diagnosis of an acute Stener lesion is important, as repair of the UCL is more difficult when treatment is delayed longer than 3 weeks. More complex ligament reconstruction procedures (eg, adductor tendon advancement, arthrodesis) may be necessary when treatment of an acute UCL injury is delayed. Long-term instability may lead to traumatic degenerative joint disease and could require arthrodesis for definitive treatment.¹⁰

Indications

Stener was able to identify a subgroup of individuals with a ulnar collateral ligament (UCL) injury who required operative intervention for the restoration of UCL integrity and, therefore, MCP joint stability. If the adductor aponeurosis is interposed between the ruptured ends of the UCL, only operative intervention will allow apposition and healing of the traumatically displaced ligament in an anatomic position. If a Stener lesion is not present, splinting of the thumb such that the torn ligament ends are reduced may lead to ligamentous healing and restoration of joint stability in select patients. The ligamentous injuries may also require surgical treatment.

Relevant Anatomy

The clearest and most eloquent anatomic depiction of the Stener lesion can be found in Stener's aforementioned article.¹ Most of the material included here is adapted from his original work.

Important structures around the metacarpophalangeal (MCP) joint include the adductor aponeurosis and tendon, the dorsal aponeurosis, the collateral ligament proper, and the accessory collateral ligament of the thumb. The adductor aponeurosis serves as an active restraint to thumb abduction but has no passive role in MCP stability. Severance of the adductor aponeurosis has no effect on lateral stability.

The ulnar collateral ligament (UCL) of the thumb is composed of 2 discernible components, the accessory and the proper. In his cadaveric dissections, Stener found that the UCL proper was taut in flexion and loose in extension, while the opposite was true for the accessory UCL. Transection of the UCL proper resulted in increased abduction with the MCP flexed but not when the MCP was held in the extended position. This instability was found to be slight and did not become severe until the accessory UCL was severed as well. The volar plate restricted abduction when the MCP was extended, even when both the UCL proper and accessory ligaments were severed.

The UCL provides lateral support and prevents volar subluxation of the MCP joint. Stability of the thumb MCP to abduction is vital for key pinch, tip pinch, and thumb opposition.

Stener described a lesion of the UCL in which the distal attachment was traumatically avulsed from the proximal phalanx of the thumb. Caught beneath the adductor aponeurosis, the severed end was unable to return to its anatomic position. The severed ligament consequently folded on itself and therefore was prevented from healing and restoring stability to the MCP joint (see image below).

With a Stener lesion, a situation exists in which the MCP joint of the thumb is rendered permanently unstable because the UCL is prevented from healing by the interposed adductor aponeurosis. The resultant chronic instability significantly impairs function in the injured hand.

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