Ultrasonographic Stress Test of the Metacarpophalangeal Joint of the Thumb

Abstract

The purpose of this study was to evaluate functional ultrasound as a tool for detecting an ulnar collateral ligament injury of the thumb. The feasability of using ultrasound for imaging the thumb joint space was tested in a pilot study, using ultrasound and dissection in 14 cadaveric hand specimens. To test this method clinically, both metacarpophalangeal joints of the thumb in 461 healthy volunteers were examined using ultrasound (11 MHz) under radial stress. The distance between the innominate tubercle of the first metacarpal head to the proximal phalanx was measured. The mean distance between the first metacarpal head and the proximal phalanx (n = 461) was 4.5 mm (standard deviation, 0.65 mm) on the right side and 4.6 mm (standard deviation, 0.61 mm) on the left side. These data were compared with data of 25 patients with an operative diagnosis of rupture of the ulnar collateral ligament of the thumb. The difference in joint space between the injured and uninjured sides was 2.25 mm (standard deviation, 0.46 mm). The metacarpophalangeal joint space can be reproducibly detected on highfrequency ultrasound. An increased gap seen on ultrasound is indicative of a rupture of the ulnar collateral ligament of the thumb.Radial abduction forces to the extended thumb often result in a rupture of the ulnar collateral ligament (UCL) of the first metacarpophalangeal (MCP) joint. 2,12 This lesion is commonly called gamekeeper's thumb or skier's thumb. Whereas the term gamekeeper's thumb originates from the occupational injury observed in Scottish gamekeepers, 5 the term skier's thumb orginated from the German literature, because downhill skiers may experience sudden abduction of the thumb when the ski pole strap wraps around their thumb during a fall.In 1962 Stener was the first to describe the displacement of the completely ruptured UCL proximal to the aponeurosis of the adductor pollicis muscle. 25 In Stener's lesion, the displaced ligament cannot fall back spontaneously to its original position and operative treatment is necessary to prevent chronic joint instability and subsequent arthritic changes. For this reason a conclusive diagnosis of the pathologic features of the UCL is crucial to determine treatment.Evaluation of UCL injuries of the MCP joint of the thumb is difficult and relies on good clinical assessment and experience. 1,21 Traditionally, diagnosis is obtained by clinical examination supported by conventional radiography, arthrography, MRI, and ultrasound studies. 6,8,9,26 Numerous authors reported good results with ultrasonographic examination of the integrity of the UCL in gamekeeper's thumb, although substantial experience of the examiner and proper hardware to distinguish the soft tissue structures seen during examination are crucial. 5,19,20,23,24 The aim of the study was to search for an easy to learn and highly reproducible ultrasound technique in the diagnosis of an UCL injury. We focused on the distance of the joint space between the innominate tubercle of the first metacarpal and the base of the pro...

Injury to the Ulnar Collateral Ligament of the Thumb

“…Ultrasound has been successfully used in differentiating Stener lesions from simple avulsions of the ulnar collateral ligament [8,22,28], but it may be misleading [36]. Magnetic resonance imaging (MRI) is more accurate (Figs.…”

Efficiency of magnetic resonance imaging for diagnosing unstable ligament injuries around the thumb metacarpophalangeal joint: A comparison to arthroscopy

“…According to early reports, the assessment of ligament injuries around the MCPJ of the thumb using MRI is highly accurate. 11, 22– 24 The sensitivity and specificity of MRI for diagnosing UCL tears of the thumb MCPJ approach 90 to 100% 2,25 Ahn et al 11 examined 18 cadaveric thumbs using MRI and reported 90% accuracy for detecting the presence of UCL tears. Plancher et al 12 reported 96% sensitivity and 95% specificity for MRI, which correlated with the surgical findings for identifying UCL rupture of the MCPJ of the thumb.…”

Injury at the Thumb UCL: Is There a Stener Lesion?

“…5 The average diagnostic characteristics in these Level I studies are as follows: sensitivity, 76%; specificity, 81%; accuracy, 81%; positive predictive value, 74%; and negative predictive value, 87%. The remaining studies are Level III clinical studies 9 -15 and cadaveric studies, 8,15 and all conclude that ultrasound is useful in evaluating injury to the UCL to the thumb.…”