Propagation of a dorsal cortical fracture of the third metacarpal bone in two horses

Seemingly, propagation of a dorsal cortical fracture in the third metacarpal bone developed after continued race performance in 2 horses. Historically, both horses had intermittent lameness that had responded to nonsteroidal anti-inflammatory drugs and brief rest periods. However, lameness in both horses had increased in severity. Radiography revealed a dorsal cortical fracture of the third metacarpal bone, with propagation of the fracture plane proximally. Fractures were incomplete and healed with stall rest in both horses.     

Advanced imaging of an incomplete fracture and exostosis of the third metacarpal bone in a young Warmblood horse

A 5-year-old Hanoverian gelding with acute moderate right forelimb lameness underwent nuclear scintigraphy, which identified marked increase in radiopharmaceutical uptake of the proximomedial aspect of the right metacarpus. Ultrasonography and radiography identified sclerosis and exostosis of the proximomedial aspect of the metacarpal bone III in-between the suspensory ligament and the second metacarpal bone, and presence of a suspected fracture. The owner requested euthanasia of the gelding, and post-mortem computed tomography and magnetic resonance imaging identified marked bone sclerosis and thickening of the palmar cortex of the metacarpal III (McIII), presence of an incomplete fracture in the palmar cortex of McIII and expansive exostosis from McIII extending in a palmar direction between the suspensory ligament and the second metacarpal bone. Histopathological examination confirmed the imaging findings of sclerosis and led to final diagnosis of a fracture of the palmar cortex of the McIII associated with an exostosis encroaching the medial aspect of the suspensory ligament. No abnormalities were present in the suspensory ligament or metacarpal bone II (McII).     

Repair of a longitudinal scapular fracture in a horse

Objective— To report repair of a longitudinal scapular fracture in a horse.
Study Design— Case report.
Animals— A 2-year-old Paint Horse colt.
Methods— A longitudinal scapular fracture was surgically repaired using four 4.5 mm dynamic compression plates.
Results— An acute longitudinal scapular fracture repaired surgically returned the horse to soundness within 6 months.
Conclusions— Internal fixation of longitudinal scapular fracture is possible with multiple 3–5 hole dynamic compression plates.
Clinical Relevance— Longitudinal fractures of the scapula should be considered when there is lateral instability of the shoulder after trauma. A displaced fracture can be adequately stabilized by internal fixation with a reasonable prognosis for soundness.     

Standing repair of an articular dorsal medial oblique fracture of the proximal third metacarpal bone in a racing Standardbred

The third metacarpal bone (McIII) is a common site of long bone fractures in racehorses. However, articular fractures of the dorsomedial aspect of McIII are a rare location of such injuries. This report describes the successful standing surgical repair of an articular fracture of the dorso-medial proximal McIII in a 4-year-old Standardbred racing mare using lag screw fixation.     

Lag screw fixation of dorsal cortical stress fractures of the third metacarpal bone in 116 racehorses

Reasons for performing study: The effectiveness and best method to manage dorsal cortical stress fractures is not clear. This study was performed to evaluate the success of lag screw fixation of such fractures in a population of Thoroughbred racehorses. Hypothesis: Lag screw fixation of dorsal cortical stress fractures is an effective surgical procedure allowing racehorses to return to their preoperative level of performance. Methods: The records of 116 racehorses (103 Thoroughbreds) admitted to Equine Medical Centre, California between 1986 and 2008 were assessed. Information obtained from medical records included subject details, limb(s) affected, fracture configuration, length of screw used in repair and presence of concurrent surgical procedures performed. Racing performance was evaluated relative to these factors using Fisher's exact test and nonparametric methods with a level of significance of P<0.05. Results: Of 92 Thoroughbred horses, 83% raced preoperatively and 83% raced post operatively, with 63% having ≥5 starts. There was no statistically significant association between age, gender, limb affected, fracture configuration or presence of concurrent surgery and likelihood of racing post operatively or of having 5 or more starts. The mean earnings per start and the performance index for the 3 races following surgery were lower compared to the 3 races prior to surgery; however, 29 and 45% of horses either improved or did not change their earnings per start and performance index, respectively. Conclusions and potential relevance: Data show that lag screw fixation is successful at restoring ability to race in horses suffering from dorsal cortical stress fractures.     

Diffuse osteomyelitis of the fourth metacarpal bone in a horse caused by Clostridium perfringens

Osteomyelitis in adult horses, often associated with trauma or iatrogenic infection following surgery, usually presents as a focal area of infected bone. Diffuse osteomyelitis, affecting both the cortex and medulla, along the full length of a bone is encountered less frequently and treatment of such infections is not well reported in horses. The 2-year-old Warmblood mare in this case was diagnosed with diffuse osteomyelitis affecting the 4th metacarpal bone with concurrent unicortical fracture of the third metacarpal bone following traumatic injury. Computed tomography (CT) aided diagnosis in this case, providing critical additional detail to that obtained with radiography and ultrasound. This case highlights the value of CT in the diagnosis of diffuse osteomyelitis. This is the first reported case of diffuse osteomyelitis caused by Clostridium perfringens in horses. Successful treatment in this case consisted of surgical debridement of the associated abscess, followed by systemic and locoregional antimicrobial therapies.     

Spontaneous fracture of the navicular bone in the horse

After a short review of previous literature about fractures of the navicular bone in horses, the symptoms and the pathological-anatomical changes of the condition are described. The most important clinical symptom is acute severe lameness without significant swellings, but with pronounced pain reaction to rotation of the coffin joint. After rest the lameness is reduced considerably, but without treatment it can persist for several years. Adherences between the deep flexor tendon and the site of the fracture and eventual damage to the coffin joint are considered to be the cause of the persisting lameness. Three case reports are given where the horses were shoed with full bar shoes with clips and high calks, and were given two months rest in a box. After that the rehabilitation was started with increasing load on the leg in question in spite of some initial lameness. The three horses all regained their full working capacity after ca. 6 months' treatment. There is no formation of callus at the site of the fracture, but only a firm formation of fibrous tissue which does not bother the horse unless the fragments are too much dislocated giving rise to a greater destruction of the coffin joint. Radiographically the fracture line persists for the rest of the horse's life.     

Keratoconjunctivitis sicca associated with fracture of the stylohyoid bone in a horse

Keratoconjunctivitis sicca developed in a mare with fracture of the stylohyoid bone. Treatment was directed at preserving the health of the globe while local inflammation at the fracture site was resolved.     

Repair of an open radial fracture in an adult horse

An open radial fracture in an adult horse (450 kg) was repaired by internal fixation, using two 18-hole 4.5-mm broad dynamic compression plates and 5.5- and 4.5-mm bone screws. The fracture healed completely, but when evaluated 9 months after surgery, the horse was lame on the fractured limb at a trot. Local infiltration of anesthesia along the distal half of the bone plates greatly ameliorated the lameness, suggesting that the plates were irritating the soft tissues and extensor tendons along the cranial and lateral aspects of the antebrachium. Both bone plates were removed simultaneously with no complications, and the horse became sound.     

Pathological fracture through a subchondral bone cyst in the proximal phalanx of a horse

A 12‐year‐old Morgan broodmare presented for a nonweightbearing right forelimb lameness. Radiography and computed tomography confirmed the presence of a pathological fracture of the proximal first phalanx through a large subchondral bone cyst (SBC) in the right forelimb and a large SBC in the proximal first phalanx of the left forelimb. Surgical repair of the large palmar medial eminence fracture of the proximal first phalanx fracture was performed using bone screws placed in lag fashion placed through stab incisions after debridement and bone grafting of the SBCs. Approximately 6 months after surgery the mare was ambulating comfortably at pasture. This case report describes a fracture through a large subchondral bone cyst in a horse despite chronicity and ongoing bone remodelling. Careful consideration regarding exercise or use should be considered in horses with large SBCs.     

Three dimensional structure of the distal condyles of the third metacarpal bone of the horse

This study examined the three-dimensional (3D) microarchitecture of regions of the equine third metacarpal bone (McIII) commonly involved in distal condylar fractures. Limbs were obtained from Thoroughbred horses (neonates to age 24 years) destroyed for inoperable fractures and a variety of other conditions. Beams, blocks and sections were cut in the principal axes, some embedded in PMMA and others examined unembedded. Several methods were used to study the 3D structure, including conventional and confocal optical microscopy, scanning electron microscopy (SEM) and radiography. The mineralised articular cartilage tends to cleave in the sagittal plane. Proximal to the subchondral bone, the main trabeculae are robust plates running in the sagittal direction with less significant mediolateral connections. Small blood vessel canals lie inside the sagittal plates. This structure gives maximum strength and protection in the sagittal plane in which the bone rotates, but offers minimal resistance to fracture propagation in this plane. The anatomical course of the common distal condylar fractures of the third metacarpal bones can be explained by underlying anisotropic structural features of the mineralised tissues.     

牦牛陈旧性蹠(掌)骨骨折断肢的截除

牦牛为一种供食用的高原肉牛种,在放牧过程中常因奔跑踏入鼠洞引起蹠(掌)骨骨折.发生骨折时,若是肥牛一般即时屠宰,如果是瘦弱牛,因种种原因难以接骨成功者,可果断行断肢截除术,此术难度不大也易成功.而对陈旧性骨折做肢体截除术则难度很大.笔者在牧区遇到并做过多例陈旧性蹠(掌)骨粉碎性骨折的断肢截除术,现将此类骨折治疗介绍如下.