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.     

Apophyseal avulsion fracture of the greater trochanter of the femur in a Thoroughbred filly

The case report of a 14-month-old Thoroughbred filly with acute onset of severe right hindlimb lameness is presented. The horse had a severe and sudden abduction of the hindlimbs due to a side effect of an overdose of lidocaine, which had been administered in a constant rate infusion after a colic surgery. Transcutaneous ultrasonography and standing radiography of the pelvis revealed proximal and cranial displacement of the greater trochanter and free bone fragments consistent with an apophyseal avulsion fracture of the greater trochanter. The complete diagnosis was obtained with the horse in a standing position. The filly was euthanatized because of deterioration resulting from the colic condition and of the poor prognosis of the fracture of the greater trochanter. Postmortem evaluation confirmed an apophyseal avulsion fracture of the right greater trochanter. To the authors' knowledge, ultrasonographic and radiographic findings of this fracture have not been described in the standing horse. The diagnosis was reached quite easily with the horse in a normal standing position when the characteristic ultrasonographic and radiographic findings were detected.     

Autologous Platelet Concentrates as a Treatment for Shoulder Injury in a Horse

Shoulder injury is an uncommon cause of lameness in horses. Trauma to the shoulder region may produce bone and soft-tissue damage. The present study describes the case of a severe left shoulder injury caused by blunt trauma in a 6-year-old gelding. Clinical and ultrasonographic examination revealed fracture of the supraglenoid tuberosity of the scapula and of the lesser tubercle of the humerus with fiber disruption and hematoma of the biceps brachii, bicipital bursitis, and suprascapular nerve damage. The gelding was successfully treated with three intralesional injections of autologous platelet concentrates administered at 2-week intervals. Although all these combined injuries took a minimum of 18 to 24 months for full recovery, the gelding reached full recuperation of the affected limb in 10 months. These results suggest that injections of autologous platelet concentrate could provide a therapeutic benefit in the treatment of shoulder bone fractures and soft-tissue injuries in horses.     

Osteosarcoma of the middle phalanx in a horse

An 11‐year‐old Thoroughbred gelding was presented for lameness investigation following acute onset hindlimb lameness, which developed during a period of paddock turnout. Clinical examination revealed a swelling over the dorsolateral aspect of the pastern that was painful on digital palpation. Radiography of this area was consistent with an aggressive bone lesion involving both joint surfaces of the middle phalanx with pathological fracture and distal collapse of this bone. On this basis, the horse was subjected to euthanasia. Post mortem histopathological examination revealed presence of an osteosarcoma without involvement of the articular cartilage. This bone tumour is extremely rare in horses and has not been reported in this anatomical location.     

Fracture repair of the distal portion of the radius by use of a condylar screw implant in an adult horse.

An 8-year-old American Quarter Horse gelding was evaluated because of an open fracture involving the left radius. The horse had fallen during training and became immediately non-weight-bearing in the left forelimb. On initial evaluation, the horse was unable to bear weight on that limb; radiography revealed a long oblique fracture of the distal metaphysis of the radius with minimal displacement of the fracture fragments. Because of the configuration of the fracture, we recommended surgical intervention with internal fixation. A condylar screw implant and 4.5-mm broad dynamic compression plate were applied to the medial and dorsolateral aspects of the radius, respectively. The horse recovered in a sling and full-limb bandage. Six months after discharge, the horse was reevaluated because of a grade 4/5 lameness in the same limb. Palpation revealed signs of severe pain over the distomedial aspect of the radius. Radiography of the left radius revealed severe osteolysis beneath the distal aspect of the condylar screw implant. Surgical removal of the medial plate was performed. Sixteen months after the initial fracture repair, the horse had returned to light training without signs of lameness. Removal of the dorsal plate may be indicated if this horse is to return to aggressive training or becomes lame in the left forelimb.     

Computed tomography assisted repair of a central tarsal bone slab fracture in a horse

A 13‐year‐old Quarter Horse gelding was presented for repair of a central tarsal bone fracture. Radiographs showed a single large nondisplaced sagittal slab fracture; however, computed tomography (CT) revealed an additional small, displaced central tarsal bone fragment. The complex fracture was repaired, under the same anaesthetic period as the CT examination, using the CT hard copies images, intraoperative fluoroscopy and radiographs. The horse recovered well and after rehabilitation showed no residual lameness at work. Computed tomography was instrumental in achieving precise screw placement and successful fracture repair.     

A large cyst in the distal femur of a horse

A 10-year-old Warmblood gelding presented with a left hindlimb lameness. Diagnostic analgesia located the lameness to the stifle. Radiography showed an unusually large cyst in the distal femur. Diagnostic arthroscopy of the stifle did not reveal any significant abnormalities. An extra-articular transcortical approach to the cyst was performed for drainage, curettage, and provision of an autologous, cancellous bone graft, gentamicin-impregnated collagen fleeces and injectable steroid. The horse returned to a higher level of competitive dressage than prior to surgery. This report describes a large cyst in the distal femur of a horse.     

Internal fixation of a greater tubercle fracture in an adolescent horse: A case report

This report describes the diagnosis of a fracture of the greater tubercle of the humerus and successful repair with 2 cancellous bone screws in a 420 kg adolescent horse.     

Vascular hamartoma as the cause of hind limb lameness in a horse

We report a 5-year-old gelding with a rare benign tumour of 2-month duration in the subcutis of the hind limb that presented with lameness. Physical examination revealed normal vital signs. Laboratory findings were within normal ranges. No bone abnormalities were detected on radiographic examination of the affected area. Bloody fluid was obtained by aspiration. Through an I-shape skin incision the tumour was excised en-block. Microscopic study showed a vascular hamartoma characterized by cavernous haemangiomatous tissue and proliferation of multiple vessels of variable diameter. This report highlights the importance of limb vascular hamartoma, as an infrequent lesion, in the differential diagnosis of lameness in the horse.     

Third tarsal bone osteonecrosis associated with chronic recurrent cellulitis in an adult horse

A 17-year-old Irish Draught cross gelding with a history of chronic recurrent right hindlimb cellulitis was evaluated due to acute onset of severe lameness affecting this limb. Scintigraphic examination identified marked radiopharmaceutical uptake within the central and third tarsal bones and the lameness improved following tibial and peroneal nerve blocks. Distal intertarsal joint collapse was observed but the radiographic changes were considered insufficient to explain the lameness severity. Magnetic resonance imaging revealed marked bone pathology affecting both the central and third tarsal bones. A subcutaneous abscess developed on the dorsolateral aspect of the limb, but clear evidence of joint infection was not established. Computed tomography showed lytic lesions affecting mainly the third tarsal bone, so the animal was treated surgically for suspected osteomyelitis involving this bone by implantation of gentamicin impregnated polymethylmethacrylate. Shortly following surgery the horse developed gastric rupture and was euthanased. Osteonecrosis of the third tarsal bone was identified, but sepsis was not demonstrated to be the cause. It is hypothesised that osteonecrosis developed as a sequel to chronic osteomyelitis which may have responded to previous antimicrobial treatment. The report also highlights the importance of gastric disorders as a differential for discomfort in animals undergoing treatment for orthopaedic disease.     

Comminuted fracture of the accessory carpal bone removed via an arthroscopic-assisted arthrotomy

A 16-year-old American paint horse gelding was presented for evaluation of a left forelimb lameness grade III/V. Radiographs and computed tomography revealed a comminuted fracture of the accessory carpal bone involving the entire articulation with the distal radius and the proximal aspect of the articulation with the ulnar carpal bone. Multiple fragments were present in the palmar pouch of the antebrachiocarpal joint. An arthroscopic-assisted open approach was necessary to remove all fractured fragments. Subsequently the horse was re-admitted for lameness and was treated successfully with antibiotics and long-term supportive bandaging.     

Arthroscopically assisted arthrodesis of the distal interphalangeal joint with transarticular screws inserted through a dorsal hoof wall approach in a horse

CASE DESCRIPTION: A 16-year-old Thoroughbred gelding was examined because of chronic right forelimb lameness. CLINICAL FINDINGS: On radiographs of the right front foot, the distal interphalangeal (DIP) joint space was narrow, and osteophytes and periarticular bony proliferation indicative of severe osteoarthritis were seen. Arthrodesis of the right DIP joint was recommended to improve the horse's comfort on the limb. TREATMENT AND OUTCOME: The horse was anesthetized, and palmar and dorsal arthroscopic approaches were used to remove as much of the articular cartilage as was accessible. Holes were then drilled through the dorsal aspect of the hoof wall, and 3 transarticular, 5.5-mm cortical screws were placed in lag fashion through these holes across the distal phalanx and into the middle phalanx. Defects in the hoof wall were filled with gentamicin-impregnated polymethyl methacrylate plugs and sealed with cyanoacrylate. Eight months after surgery, fusion of the DIP joint was evident radiographically and the horse was sound at a walk. CLINICAL RELEVANCE: Transarticular placement of cortical screws through a dorsal hoof wall approach combined with arthroscopically guided cartilage removal can result in fusion of the DIP joint in horses.     

Osseous cyst‐like lesions of the lateral intertubercular groove of the proximal humerus: A report of 5 cases

This report documents the case presentation, evaluation, treatment and outcome of 5 horses with an osseous cystlike lesion (OCLL) of the intertubercular groove of the proximal aspect of the humerus. In 3 of the 5 cases, delayed phase gamma scintigraphic findings demonstrated increased radiopharmaceutical uptake in the region of the intermediate tubercle of the proximal humerus of the affected limb, demonstrating increased bone remodelling in this region. In 4 of the 5 horses, an OCLL was identified in the intermediate tubercle of the proximal humerus, and in one horse the OCLL was identified in the greater tubercle. Medial‐lateral and craniomedial‐caudolateral oblique radiographic views were helpful to see the lesions in all cases. Ultrasonography confirmed the location of the subchondral and fibrocartilage defect associated with the OCLL and confirmed communication of the cyst with the lateral intertubercular groove of the humerus in 3 of the 5 cases. Ultrasonography also confirmed a variable degree of bicipital tendonitis in 3 of the horses. OCLL of the lateral intertubercular groove of the proximal humerus should be considered in the evaluation of any mature horse with lameness isolated to the bicipital bursa. Development of these OCLL may be a result of trauma or altered limb biomechanics as a result of shoulder osteoarthritis or concurrent chronic lameness, which leads to disruption or thinning of the fibrocartilage, remodelling of the subchondral bone and subsequent cyst development.     

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.     

Excision of the distal sesamoid bone for treatment of infection of the digit in a heifer.

An 8-month-old Holstein heifer was evaluated for right hind limb lameness of 3 weeks' duration. Diagnoses were osteomyelitis and fracture of the distal sesamoid bone, septic arthritis of the distal interphalangeal joint, and osteomyelitis of the third phalanx. After excision of a section of tissue from the plantar aspect of the digit and partial section of the deep digital flexor tendon, the distal sesamoid bone was excised. The third phalanx was curetted, and the surgical wound was lavaged. Twenty months after surgery, the heifer was fully weightbearing on the affected digit. Surgical exploration of the digit should be considered an alternative to claw amputation in cattle that have severe digital infections.     

Alternative surgical treatment for synovial ganglion cyst of the digital tendon sheath in one horse

A 6-year-old Highland pony gelding was presented with severe left fore (LF) limb lameness of acute onset. The lameness occurred concomitantly with mild digital flexor tendon sheath (DFTS) effusion and focal painful swelling on the lateral aspect of the LF fetlock region. Clinical examination and diagnostic analgesia localised the lameness to the fetlock region and on ultrasound, a cyst-like structure filled with anaechoic fluid was detected just proximal to the lateral sesamoid bone, at the proximo-lateral aspect of the DFTS and adjacent to the lateral neurovascular bundle. Communication between the cyst-like structure and the DFTS was suspected ultrasonographically and then confirmed with contrast tenography. Tenoscopic examination of the LF DFTS was performed and the communication between the fluid-filled structure and the synovial cavity was detected. The defect in the DFTS wall was enlarged tenoscopically and the lining of the cyst-like structure was debrided. The horse recovered well post-operatively and was back in work with no evident lameness 8 months after surgery. This alternative minimally invasive surgical treatment had an excellent outcome and has the advantage of reducing the risk associated with en bloc resection.     

Skeletal metastasis from a squamous cell carcinoma of the nictitating membrane in a Haflinger horse

A 12-year-old Haflinger gelding with a history of a persistent cough was referred for evaluation of a severe lameness of the left forelimb. An excision of the right nictitans had been performed 2 years prior to presentation, and a squamous cell carcinoma (SCC) with embolic neoplastic cells in several blood vessels had been confirmed by histopathology. The origin of the lameness could not be localised with regional analgesia; therefore, a nuclear scintigraphic examination was performed. This revealed an area of marked increased radiopharmaceutical uptake at the level of the caudodorsal border of the left scapula. Further examination, including ultrasound-guided biopsy of the suspect region, confirmed the presence of SCC invading the scapula. Due to poor a prognosis, the horse was subjected to euthanasia. Prior to euthanasia, the gelding was tested homozygous for the missense variant in the damage-specific DNA-binding protein 2 (DDB2) gene, which is reported as a risk factor for the development of nictitans SCC in Haflinger horses. Post-mortem evaluation revealed multiple SCC metastasis, affecting the scapula, the liver and the lungs. To the authors' knowledge, this is the first reported case of bone metastasis following a primary periocular SCC in a horse.     

Collateral ligament reconstruction in two horses following traumatic avulsion fracture using a knotless suture anchor construct

This case report describes a technique for repair of medial collateral ligament avulsions in two horses. Both horses sustained traumatic injuries resulting in avulsion fractures at the origin of their medial tarsal and carpal collateral ligaments. This report describes the use of a knotless suture anchor to mechanically reconstruct medial collateral ligament avulsion injuries in two horses. The first horse, a 9‐year‐old Hannovarian Warmblood gelding presented for an acute nonweightbearing lameness in the right hindlimb. The injury was localised to the medial malleolus of the tibia and an avulsion fracture of the origin of the short medial collateral ligament of the tibiotarsal joint with disruption of the ligament was found on radiographs and ultrasound. The horse was taken to surgery and a reconstruction of the short medial collateral ligament was performed with a modified single row construct using a biocompatible, multistrand, long chain ultra‐high molecular weight polyethylene braided composite suture tape (2 mm Fibertape) and a single knotless suture anchor (5.5 × 19.1 mm PEEK SwivelLock C). The second horse, a 5‐year‐old Thoroughbred gelding presented for an acute nonweightbearing lameness in the left forelimb. The injury was localised to the medial styloid process of the radius and an avulsion fracture of the origin of the medial collateral ligament of the antebrachial carpal joint was found on radiographs and ultrasound. The horse was taken to surgery and a similar reconstruction procedure was performed to the collateral ligament. Both horses were recovered in a Robert Jones bandage without the use of casts or splints and recovered without incident. Both horses are sound and returned to previous level of athletic performance at 18 months and 8 months, respectively.     

PREVALENCE OF COMPUTED TOMOGRAPHIC SUBCHONDRAL BONE LESIONS IN THE SCAPULOHUMERAL JOINT OF 32 IMMATURE DOGS WITH THORACIC LIMB LAMENESS

Osteochondrosis is a common developmental abnormality affecting the subchondral bone of immature, large breed dogs. The purpose of this retrospective study was to describe CT lesions detected in scapulohumeral joints of 32 immature dogs undergoing CT for thoracic limb lameness. Eight dogs (14 scapulohumeral joints) had arthroscopy following imaging. Thirteen dogs (19 scapulohumeral joints) were found to have CT lesions, including 10 dogs (16 scapulohumeral joints) with subchondral bone lesions and 3 dogs with enthesopathy of the supraspinatus tendon. In one dog, subchondral bone lesions appeared as large oval defects within the mid‐aspect of the glenoid cavities, bilaterally. These lesions resembled osseous cyst‐like lesions commonly identified in the horse. This is the first report of such a presentation of a subchondral bone lesion in the glenoid cavity of a dog. In all dogs, small, focal, round or linear lucent defects were visible within the cortical bone at the junction of the greater tubercle and intertubercular groove. These structures were thought to represent vascular channels. Findings from this study support the use of CT as an adjunct modality for the identification and characterization of scapulohumeral subchondral bone lesions in immature dogs with thoracic limb lameness.     

Proximal interphalangeal joint arthrodesis in 34 horses using two parallel 5.5-mm cortical bone screws

OBJECTIVE: To report clinical experience with arthrodesis of the proximal interphalangeal joint in horses using two parallel 5.5-mm cortical bone screws placed in lag fashion. STUDY DESIGN: Retrospective, clinical study. ANIMALS: Thirty-four horses, aged 1 to 19 years. METHODS: Medical records for all horses admitted (1991-1997) for pastern arthrodesis using two 5.5-mm ASIF cortical bone screws, in parallel orientation, and placed in lag fashion by use of a combined aiming device to facilitate accuracy were reviewed. Signalment, lameness diagnosis, duration of lameness, limb(s) involved, and outcome were recorded. Criteria for successful outcome were determined as return to previous level of function or future intended athletic use. RESULTS: Thirty-nine proximal interphalangeal joint arthrodeses were performed on 34 horses. One horse was euthanatized in the recovery room and was excluded from data analysis. Successful outcome occurred in 85% of frontlimbs and 89% of hindlimbs. Failure occurred in 5 joints; 1 horse had lameness directly associated with surgery, whereas 4 horses had unrelated lameness. CONCLUSION AND CLINICAL RELEVANCE: Age, breed, and initial disease did not affect outcome. Arthrodesis of the proximal interphalangeal joint by use of two 5.5-mm ASIF cortical bone screws, in parallel orientation, placed in lag fashion by use of a combined aiming device, resulted in sound use of the limb in >85% of the joints with shortened postoperative coaptation.