Hallux saltans due to stenosing tenosynovitis of flexor hallucis longus: dynamic sonography and arthroscopic findings

Abstract

Triggering of the toes is rare, with isolated cases reported in the literature involving predominantly the flexor hallucis longus (FHL) tendon, a condition known as "hallux saltans" (HS). We report the dynamic sonographic findings of a 42-year-old female with a 2-month history of ankle pain and triggering of right hallux, consistent with HS. Sonography demonstrated tenosynovitis and focal thickening of FHL at the level of hindfoot, with a fibrous band adjacent to the tendon. Dynamic ultrasound showed triggering and snapping of FHL tendon during hallux flexion and extension, respectively. We present comprehensive documentation of this rare entity, including sonographic still images and cine clips, as well as correlation with arthroscopic surgical findings.

Posterior Ankle Arthroscopy for Flexor Hallucis Longus Entrapment: A Case Report

“…Stenosing tenosynovitis is a chronic disorder frequently observed in finger triggering of a digit during flexion and subsequent snapping at extension [ 6 ]. Trigger finger is mainly caused by the inflammation in the flexor tendon sheath and thickening of the pulleys [ 6 , 7 ]. Regarding the toes, although stenosing tenosynovitis of the FHL has already been reported in a few cases, the clinical condition is rare [ 7 , 8 ].…”

“…Trigger finger is mainly caused by the inflammation in the flexor tendon sheath and thickening of the pulleys [ 6 , 7 ]. Regarding the toes, although stenosing tenosynovitis of the FHL has already been reported in a few cases, the clinical condition is rare [ 7 , 8 ]. It is recognized as hallux saltans, and most cases are observed among sports players, especially ballet dancers [ 4 , 9 ].…”

“…They concluded that ultrasonography was a better diagnostic method than radiographs to visualize the plantar capsular accessory ossicle due to its lack of ossification. Martinez-Salazar et al also demonstrated the FHL entrapment by using dynamic sonography, indicating the thickening of the FHL adjacent to the fibrous band at the medial ankle [ 7 ]. Although we did not perform dynamic sonography in this study, we agree with these authors that this evaluation will provide valuable information like real-time inspection of tendon motion and visual confirmation of the entrapment [ 7 , 15 ].…”

“…Martinez-Salazar et al also demonstrated the FHL entrapment by using dynamic sonography, indicating the thickening of the FHL adjacent to the fibrous band at the medial ankle [ 7 ]. Although we did not perform dynamic sonography in this study, we agree with these authors that this evaluation will provide valuable information like real-time inspection of tendon motion and visual confirmation of the entrapment [ 7 , 15 ]. Therefore, the diagnostic efficacy should be enhanced by combining imaging modalities, such as ultrasonography, radiographs, CT, and MRI.…”

Endoscopic treatment of trigger toe

“…O hallux saltans é um tipo raro de tenossinovite estenosante do ten dão FLH (9) , sendo mais encontrado em dançarinos de balé clássico (3) . Em um estudo recente de 2018, um caso de hallux saltans é liberado endoscopicamente, utilizandose técnica semelhante, enfatizando os achados ultrassonográficos (10) .…”