Ulnar Collateral Ligament

Tears of the ulnar collateral ligament of the thumb, referred to as gamekeeper s or skier s thumb are frequently encountered as a result of skiing injury. The torn ligament may become interposed beneath the adductor aponeurosis resulting in the... 

Stener lesion, which requires surgery as healing hy secondary intention will not occur. On ultrasound there is disruption of the ulnar collateral ligament with the Stener lesion appearing as a hypoechoic focal mass lying above the joint line (Ebrahim et al. 2006 O Callaghan et al. 1994). 

Avulsion fractures of the medial epicondyle are seen between the ages of 9 and 15, after the apophysis becomes a separate ossification nucleus from the epiphysis of the distal humerus and before it fuses with the distal humerus. The medial epicondyle is a traction apophysis for the flexor group of forearm muscles, and also serves as an attachment for the ulnar collateral ligaments and the joint capsule. This injury accounts for up to 10% of elbow fractures. 

Fig. 19.25. Avulsion fracture of the ulnar collateral ligament at the thumb metacarpophalangeal joint...

The medial collateral ligamentous complex, also known as the ulnar collateral ligament, is composed of three bands in continuity with each other anterior, posterior and oblique (Fig. 8.3a). The anterior band is the most conspicuous and extends from the medial epicondyle to the medial aspect of the coronoid process, providing the major constraint to valgus stress. The posterior band arises from the posterior aspect of the medial epicondyle and inserts into the medial edge of the olecranon. The oblique band, commonly referred to as the ligament of Cooper , is the weakest and bridges the insertions of the anterior and posterior bands on the ulna. 

The lateral aspect of the elbow is best examined with both elbows in extension, thumbs up, palms of the hands together (Barr and Babcock 1991). When examining the radial collateral ligament and the capsule, the elbow should be extended, keeping the hand pronated. Along the lateral elbow, high-resolution US can demonstrate the common extensor tendon, the lateral ulnar collateral ligament, the radial nerve with its superficial and deep (posterior interosseous nerve) branches, and the radio-capitellar joint. 

The common extensor tendon origin is best visualized in longitudinal planes as a beak-shaped hyperechoic structure located between the subcutaneous tissue and the lateral ulnar collateral ligament (Fig. 8.18). Deep to this tendon, the lateral epicon-dyle appears as a smooth down-sloping hyperechoic structure. The individual contributions from the extensor muscles to the common extensor tendon cannot be discriminated with US because they are... 

In lateral epicondylitis, the lateral elbowligamentous complex, and especially the lateral ulnar collateral ligament, should be routinely assessed because this ligament is commonly injured in association with tears of the common extensor tendon as a result of the same forces or overuse mechanisms on adjacent structures (Bredella et al. 1999). An unsuspected tear of this ligament may be the cause of conservative therapy failure in patient with lateral epicon-... 

Fig. 8.41. Partial-thickness tear of the common extensor tendon. Long-axis 12-5 MHz US image in a manual laborer who presented with acute onset of lateral elbow pain reveals a linear hypoechoic split star) extending from the lateral epicondyle (LE) through the substance of the common extensor tendon origin. The torn deep libers arrowheads) are retracted just distal to the hypoechoic area. Note the integrity of the underlying lateral ulnar collateral ligament asterisks). RH, radial head...

Bredella MA, Tirman PF, Fritz RC et al (1999) MR imaging findings of lateral ulnar collateral ligament abnormalities in patients with lateral epicondylitis. AJR Am J Roentgenol 173 1379-1382... 

De Smet AA, Winter TC, Best TM et al (2002) Dynamic sonography with valgus stress to assess elhow ulnar collateral ligament injury in hasehall pitchers. Skeletal Radiol 31 671-676... 

Nazarian LN, McShane JM, Ciccotti MC et al (2003) Dynamic US of the anterior band of the ulnar collateral ligament of the elbow in asymptomatic major league baseball pitchers. Radiology 227 149-154... 

The metacarpophalangeal joint of the thumb plays a major role in handgrip. Similar to the other fingers, the radial and ulnar collateral ligaments of the thumb join the metacarpal head to the base of the proximal phalanx, limiting translational movements of the thumb in the coronal plane. From the functional point of view, the ulnar collateral ligament plays the most important role because it prevents exces-... 

Fig. 11.60. Gamekeeper s thumb. Schematic drawing illustrates the mechanism of ulnar collateral ligament tear. Typically, the ligament rupture is the end result of a vigorous valgus stress (curved arrow) applied on the metacarpophalangeal joint leading to excessive tension (black arrows) on the ligament. Note the relationship of the ulnar collateral ligament (in black) with the extensor poUicis longus tendon (epl) and the adductor pollicis aponeurosis (open arrows)...

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