Ultrasound features of a pulley strain in a sport climber: a discussion based on a case report

Abstract

Ruptures of the annular pulleys of the finger flexor tendons are not common in the general population. In sport climbing, these structures can be abnormally stressed, mainly because of the so-called crimped position, an extreme flexion of the proximal interphalangeal joint, levering an abnormal tension by flexor tendons. Complete pulley tears manifest with explicit pain and an inability, but strains or minor tears might only be perceived by individuals like professional climbers, since they can bring total disability to crucial grip positions. Complete tears of one or more pulleys have already been characterized by ultrasound and magnetic resonance, but no imaging features were described for strains or smaller partial tears. We describe the case of a climber with symptoms of an A2-pulley injury, in whom ultrasound imaging revealed reversible features of fusiform thickening and hypoechogenicity, which resemble the strains that we find in similar structures like tendons and other ligaments.

Keywords: Climbing; Pulley; Rehabilitation; Strain; Ultrasound.

Fig. 1

The crimped position, a climbing holding type that consists of grabbing a small edge with a flexed proximal interphalangeal joint

Fig. 2

Ultrasound image of the A2-pulley and finger flexor tendons of the fourth left finger in a long-axis sagittal view. Legend: arrows—A2-pulley; asterisk—finger flexor tendons; cardinal—proximal phalanx bone cortex

Fig. 3

Ultrasound images of the A2-pulleys of the fourth finger, comparing the injured left side with the uninjured right one, either in short axis view (a and b) and long axis view (c and d). Figures a and b display a short axis view of the A2-pulley at its radial and distal part, the first being the injured left side, depicting a fusiform and disproportionate thickening on the left side (1.81 mm at the left versus 1.05 mm at the right), alongside with relative hypoechogenicity. Figures c and d display a long-axis coronal view of the A2-pulley at its radial part, the first being the injured left side, both showing a thickening of the more distal part, but disproportionately bigger on the injured left side (1.50 mm at the left versus 0.98 mm at the right), with proximal segments being equally thick. Legend: arrows—A2-pulley; asterisk—finger flexor tendons; cardinal—proximal phalanx bone cortex

Fig. 4

Ultrasound images of the A2-pulley of the injured left fourth finger, six weeks after avoidance of the crimped position while maintaining remaining climbing activities, with a short-axis view of the radial and distal part (a) and long-axis coronal view of the radial part (b) showing a significant decrease of the previous pathological findings, namely a reduction in thickness of the same A2-pulley from 1.81 to 1.31 mm, in short axis view, and from 1.50 to 0.96 mm, in long axis coronal view. Legend: arrows—A2-pulley; asterisk—finger flexor tendons; cardinal—proximal phalanx bone cortex