Frontal plane fractures of the accessory carpal bone and implications for the carpal sheath of the digital flexor tendons.

Authors: Minshall G J, Wright I M

Journal: Equine veterinary journal

DOI: 10.1111/evj.12203 PubMed: 24164449Log in to save

Summary

# Editorial Summary: Frontal Plane Fractures of the Accessory Carpal Bone Frontal plane fractures of the accessory carpal bone (ACB) have been poorly characterised in the literature, particularly regarding their relationship with the carpal sheath and the deep digital flexor tendon (DDFT) housed within it. Minshall and Wright's retrospective analysis of nine cases referred to a specialist hospital between 2006 and 2012 used radiographic, ultrasonographic, and tenoscopic imaging to document the anatomical features and clinical consequences of these fractures. All eight displaced fractures communicated directly with the carpal sheath, with comminuted fragments and protruding fracture margins causing characteristic lacerations to the lateral margin of the DDFT—findings readily identifiable on ultrasound and confirmed at tenoscopy in seven cases. Remarkably, aggressive surgical management involving removal of torn tendon tissue and debridement of fracture debris resulted in return to work in all seven surgically treated horses, whilst the single non-displaced fracture healed uneventfully with immobilisation alone. These findings fundamentally alter how frontal plane ACB fractures should be approached clinically; ultrasonographic examination to assess DDFT integrity is essential for prognosis, and referral for tenoscopic debridement appears justified given the excellent functional outcomes reported, even in cases with significant tendon trauma.

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Practical Takeaways

•Displaced ACB fractures in the frontal plane should be assumed to have caused DDFT trauma and require tenoscopic evaluation and debridement for optimal outcomes
•Ultrasonography can identify DDFT lesions before tenoscopy, helping confirm the diagnosis and plan treatment
•Surgical removal of comminuted bone fragments and protruding fracture edges from the carpal sheath offers good prognosis (7/8 cases returned to work), whereas nondisplaced fractures may be managed conservatively

Key Findings

•All 8 displaced ACB fractures communicated with the carpal sheath and lacerated the DDFT, while 1 nondisplaced fracture did not
•Comminuted fragments displaced distally within the carpal sheath to mid-metacarpal level or abaxially extrathecally
•7 of 7 horses treated with debridement and fracture fragment removal returned to work; 1 nondisplaced fracture healed with immobilization and returned to work

Conditions Studied

frontal plane fractures of the accessory carpal bonedeep digital flexor tendon lacerationcarpal sheath injury

Related References

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