Isolated A1 Pulley Rupture of Left Fourth Finger in Kendo Players: Two Case Reports

Abstract

Annular pulley injury of fingers is usually observed in rock climbers who support their entire body weight with flexed fingers during climbing. But these lesions can also follow trivial trauma, such as lifting heavy objects with the fingertips, or during sports and recreational activities. The A2 and A4 pulleys are most usually involved and reported most frequently. However, traumatic A1 pulley rupture has not been reported yet, to the best of our knowledge. Kendo is a very vigorous martial art with frequent physical contact. Therefore, we reported two cases of repetitive microtraumatic left fourth finger A1 pulley rupture in Kendo players with results from physical examination and imaging studies, such as ultrasonography and magnetic resonance imaging, together with related literature.

Keywords: Athletic injuries; Finger injuries; Ultrasonography.

Fig. 1. Physical examination of both hands during finger motions. There is no difference between both palms during finger extension, but the protrusion of left fourth finger flexor tendon from palm is demonstrated during resistive finger flexion, as compared to the right side.

Fig. 2. Ultrasonography of first patient's fourth fingers at metacarpophalangeal joint area during active forced flexion position. The A1 pulley (arrow) is observed in right side (A), but it (arrow) is not observed in left side (B) and flexor tendon is separated from volar plate (arrow head) (B). Left fourth A1 pulley is not observed and the flexor tendon is in contact (asterisks) with subcutaneous tissue directly (D), as compared to right fourth A1 pulley (C). PP, proximal phalanx; MeT, metacarpal head; F, flexor tendon.

Fig. 3. Proton density MR images of both fourth finger flexor tendons. The flexor tendon of left fourth finger (A) is not anchored to metacarpal head and detached (arrow), as compared to flexor tendon of right fourth finger (B). A2 pulley is located at proximal region of proximal finger (C), which is intact in left finger (A). Axial MR images also show A1 pulley injury (arrowhead) on left fourth finger (D), as compared to right fourth finger (E) [9]. PP, proximal phalanx; MeT, metacarpal head; F, flexor tendon; MR, magnetic resonance.

Fig. 4. Ultrasonographic findings of the second patient's fourth fingers at metacarpophalangeal joint area (bilateral) during active forced flexion position. The A1 pulley (arrow) is observed at the right side (A), but not observed at the left side (B), and the 3rd A1 pulley (arrow head) is observed (C). However, the left fourth A1 pulley is not observed and the flexor tendon is in contact with subcutaneous tissue directly (C). PP, proximal phalanx; MeT, metacarpal head; F, flexor tendon.

Fig. 5. Bamboo sword grip method. The Kendo player usually grips the bamboo sword anteriorly with his/her right hand and posteriorly with his/her left hand. (A, B) The tip of the bamboo sword is located at the left palm.