Computed tomographic imaging and surgical management of distal insertional avulsion fragments of the caudal cruciate ligament in four horses.

OBJECTIVE: To describe cases with caudal cruciate ligament (CdCL) avulsion fragments diagnosed based on computed tomography (CT) examination and report on arthroscopic fragment removal. ANIMALS: Four Warmblood horses with hindlimb lameness and osseous fragments located in the caudal medial femorotibial joint (mFTJ). STUDY DESIGN: Short case series. METHODS: CT and arthroscopic evaluation of the caudal mFTJ were performed. The caudal mFTJ and the insertion of the CdCL on the tibia were assessed and removal of the avulsion fragments was attempted in three horses using a cranial intercondylar approach. RESULTS: The fragment was not accessible via caudomedial approaches in one horse. A cranial intercondylar approach was used in three horses, allowing removal of the intra-articular fragment in two horses, and removal of two-thirds of the proximal fragment in the last horse. Acute, profuse, arterial bleeding occurred in this horse during surgery with transient postoperative soft tissue swelling. Comorbidities included medial femoral condyle cartilage defects (3), cranial cruciate ligament lesions (2), and medial collateral ligament lesions (2). Horses were followed up for 16 months (median, range 11-28 months), at which point all were back in ridden exercise; owners' satisfaction was good. CONCLUSION: CT examination confirmed the diagnosis and allowed evaluation of the stifle joint for comorbidities. A cranial intercondylar arthroscopic approach facilitated the removal of CdCL insertional avulsion fragments, although not always complete. CLINICAL SIGNIFICANCE: A cranial intercondylar approach can allow access to CdCL avulsion fragments, but complications and incomplete removal remain possible.

Dynamic three-dimensional computed tomographic imaging facilitates evaluation of the equine cervical articular process joint in motion.

BACKGROUND: Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. OBJECTIVES: To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. STUDY DESIGN: Descriptive cadaver imaging. METHODS: Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck specimens and perform dynamic 2D and 3D CT imaging. Images were obtained with a 320-detector-row CT scanner with a 160 mm wide-area (2D) solid-state detector design that allows image acquisition of a volumetric axial length of 160 mm without moving the CT couch. Dynamic videos were acquired and divided into four phases of movement. Three blinded observers used a subjective scale of 1 (excellent) to 4 (poor) to grade the overall image quality in each phases of motion cycle. RESULTS: With an overall median score of 1 the image quality, a significantly lower score was observed in the dynamic 3D videos over the four phases by the three observers compared with the 2D videos for both flexion (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P = .007) and extension movement (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P = .008). Median Translational displacement of the APJ surface was significantly greater in flexion than in extension movement (P = .002). MAIN LIMITATIONS: The small number of specimens included. Excision of spines and removal of musculature. CONCLUSIONS: The study is a first step in the investigation of the potential of dynamic 3D CT in veterinary medicine, a technique that has only begun to be explored and leaves much room for refinement prior to its introduction in routine practice. CT with a detector coverage of 16 cm and a rotation speed of 0.32 seconds provides high-quality images of moving objects and gives new insight into the movement pattern of equine cervical APJs.

Objective evaluation for analgesia of the distal interphalangeal joint, the navicular bursa and perineural analgesia in horses with naturally occurring forelimb lameness localised to the foot.

BACKGROUND: The outcome and interpretation of intra-synovial diagnostic analgesia of the distal interphalangeal joint (DIPJ) and the navicular bursa (NB) remain in dispute, and no objective studies have been carried out to establish the percentage of improvement over time from these two analgesia techniques. OBJECTIVES: To investigate the qualitative and time-dependent outcome of DIPJ-A and NB-A in naturally occurring forelimb lameness. STUDY DESIGN: Case series. METHODS: Twenty-three clinical cases with forelimb lameness were evaluated objectively using a body mounted inertial sensor system (BMIS). Lameness was localised to the foot with a palmar digital nerve block and/or an abaxial sesamoidean nerve block on day 1, and analgesia of the DIPJ (DIPJ-A) and NB (NB-A) were performed on days 2 and 3. Improvement following perineural analgesia was measured after 10 min and intra-synovial blocks after 2-, 5- and 10-min. Horses with at least 70% improvement measured objectively after diagnostic analgesia were included in the study. RESULTS: There was no significant association between improvement following perineural analgesia and the DIPJ-A and NB-A. The mean improvement in the lameness differed between DIPJ-A and NB-A at 2 min (p < 0.001) and at 5 min (p = 0.04), and it was no longer observed after 10 min (p = 0.06). A positive NB-A produced a high degree of improvement that remained stable, whereas the DIPJ-A improved over time. MAIN LIMITATIONS: Perineural and intra-synovial analgesia were performed without contrast medium to assess the diffusion of mepivacaine. CONCLUSIONS: Our results suggest that perineural analgesia is not reliable enough to differentiate pain originating from DIPJ and NB. Early evaluation of the DIPJ-A and NB-A can determine the origin of the pain. An improvement following NB-A was constant over time, but an improvement following DIPJ-A varied by up to 10 min.

Application of locking compression plates as type 1 external fixators to treat unilateral mandibular fractures in four equids and one dromedary.

OBJECTIVES: To describe a novel fixation of open, unstable, unilateral mandibular fractures applying a locking compression plate as an external skeletal fixator (ESF-LCP). ANIMALS: Four horses and one dromedary. STUDY DESIGN: Short case series. METHODS: Animals presented with unstable, open, unilateral fractures of the mandible. Fracture fixation was performed under general anesthesia. A 4.5/5.5 narrow LCP was applied externally above the level of the skin and combined with intraoral tension band wiring. RESULTS: Fracture fixation was achieved successfully using an ESF-LCP. Minimal tissue manipulation was required during application and removal of the construct. The ESF-LCPs provided adequate access to the wounds at the fracture site, were well tolerated, and did not interfere with any objects in the animals' environment. Mild drainage at the screw-skin interface developed in all cases, requiring early implant removal due to surgical site infection in one case. The use of longer plates was associated with superficial pressure necrosis of the skin in the masseter area in two cases. Implants were removed after 3 to 12 weeks, and the long-term functional outcome after 11 to 41 (median 13) months was good in all cases. CONCLUSION: Stabilization of mandibular fractures with ESF-LCP led to good outcomes in this case series. The use of longer plates positioned more caudally and in a ventrolateral position seemed associated with surgical site infection and pressure necrosis of the skin. CLINICAL SIGNIFICANCE: Use of a locking compression plate as an external skeletal fixator seems to offer a viable alternative to treat unilateral mandibular fractures, especially when these are open and/or infected.