Flexor Hallucis Longus decompression under ultrasound guidance: A cadaver study

Area of Science:

• Orthopedic Surgery
• Musculoskeletal Imaging
• Anatomy

Background:

• The Flexor Hallucis Longus (FHL) tendon can be impinged, leading to conditions like functional Hallux Limitus, often requiring surgical tenolysis.
• Current surgical options for FHL tenolysis include arthroscopic or open surgery to release the retrotalar pulley.

Purpose of the Study:

• To evaluate the risk of neurovascular and posterior tibial tendon injuries during ultrasound-guided tenolysis of the FHL tendon.
• To test the hypothesis that FHL tenolysis can be performed safely under ultrasound guidance without causing iatrogenic lesions.

Main Methods:

• The study analyzed 13 cadaveric specimens (26 feet), performing ultrasound-guided FHL tenolysis using a 19-gauge needle after hydrodissection.
• An orthopedic specialist conducted the tenolysis, and subsequent dissection verified the integrity of the posterior tibial pedicle, FHL tendon, and retrotalar pulley opening.

Main Results:

• Complete release of the retrotalar pulley in 10 cases resulted in 5 tibial nerve lesions, 4 vascular lesions (1 venous, 3 arterial), and 6 FHL tendon lesions.
• Partial release (65.87±18% section) in 16 cases showed no neurovascular or tendinous injuries.

Conclusions:

• Ultrasound-guided FHL tenolysis at the retrotalar pulley is linked to neurovascular and tendon damage when a complete release is achieved.
• Partial release of the retrotalar pulley via ultrasound guidance appears to be a safer alternative, avoiding iatrogenic lesions.