Use of preoperative computed tomography (CT) to plan repair of comminuted fractures of the middle phalanx in six Warmblood horses: Configuration, treatment and long-term outcome.

Overview

• This study evaluated how preoperative computed tomography (CT) scans aid in planning surgery for complex middle phalanx fractures in Warmblood horses, focusing on fracture details, concurrent injuries, surgical technique, and long-term outcomes.

Study Objective

• To determine the additional benefits of CT imaging over traditional radiography in surgical planning and repair of comminuted middle phalanx fractures in Warmblood horses.

Subjects and Methods

• Six adult Warmblood horses with comminuted fractures of the middle phalanx involved in the study.
• All horses underwent both standard radiographic and preoperative CT examinations.
• A standardized fast protocol (SFP) was applied for assessing CT images to enhance evaluation efficiency and consistency.
• Surgical intervention included repair of the fracture plus proximal interphalangeal joint arthrodesis, stabilized using two dorsally located plates under general anesthesia.
• Long-term follow-up data (>6 months) were collected from clinical records and referring veterinarians to assess patient outcomes post-surgery.

Key Findings from CT Imaging

• CT provided critical diagnostic information unavailable through radiography in all cases, highlighting its superior imaging capability for complex fractures.
• In two horses, CT identified small navicular bone fractures at the dorsal cortex within the distal interphalangeal joint that radiographs missed.
• In one horse, CT revealed a rupture of the deep digital flexor tendon (DDFT), a crucial concurrent injury that could affect surgical planning and prognosis.
• CT imaging allowed for accurate planning of screw placement — specifically, positioning two or more independent 4.5/5.5 mm cortical lag screws — to maximize construct stability during repair.

Surgical Treatment and Outcomes

• The approach combined fracture fixation with joint arthrodesis, using dual dorsal plating to stabilize the middle phalanx and proximal interphalangeal joint.
• All surgeries were performed under general anesthesia following CT-assisted planning.
• At long-term follow-up, four horses were alive and exhibited only mild lameness (graded 3/5 on the American Association of Equine Practitioners (AAEP) scale), indicating relatively good functional recovery.

Conclusions and Clinical Implications

• Preoperative CT using a standardized fast protocol significantly enhanced visualization of fracture complexity and concurrent pathologies beyond what was possible with radiographs alone.
• The ability to detect small fractures and tendon injuries preoperatively improved surgical planning and implant positioning, contributing to better biomechanical stability of the repair construct.
• CT imaging is therefore recommended for complex middle phalanx fractures to optimize surgical outcomes and potentially improve long-term limb function in horses.