Mandibular condylectomy in a standing horse for treatment for osteoarthritis of the temporomandibular joint

An Irish Sport Horse mare presented for evaluation and treatment of inability to masticate effectively with subsequent severe weight loss. A slowly expanding, firm, nonpainful mass was noted at the left temporomandibular joint. Radiographic examination revealed extensive osteoarthritic changes of this joint. Due to the age and debilitated condition of the horse, along with financial constraints on the owner's behalf, the decision was made to perform a mandibular condylectomy as a standing procedure using sedation and local and regional anaesthesia techniques. The mare tolerated the procedure very well and post operatively improved significantly.     

Fusobacterium necrophorum septic arthritis of the temporomandibular joint in an Australian Stockhorse mare

Septic osteomyelitis of the temporomandibular joint (TMJ) is rarely seen in equine medicine with few reported cases, and none reported involving Fusobacterium necrophorum. This report describes the diagnosis and successful treatment of septic osteomyelitis of the temporomandibular joint (TMJ) in an 11-year-old Australian Stockhorse mare in Queensland, Australia.     

Computed tomographic anatomy of the temporomandibular joint in the young horse

Reasons for performing study: The equine temporomandibular joint (TMJ) and its surrounding structures can be difficult to investigate in cases with a clinical problem related to the region. Little previous attention has been given either to a computed tomographic (CT) imaging protocol for the joint or an interpretation of the structures displayed in CT images of the normal joint. Objectives: To provide a CT atlas of the normal cross‐sectional anatomy of the equine TMJ using frozen and plastinated sections as anatomical reference. Methods: Eight TMJs from 4 immature pure‐bred Spanish horses were examined by helical CT. Scans were processed with a detailed algorithm to enhance bony and soft tissue. Transverse CT images were reformatted into sagittal and dorsal planes. Transverse, sagittal and dorsal cryosections were then obtained, photographed and plastinated. Relevant anatomic structures were identified in the CT images and corresponding anatomical sections. Results: In the CT images, a bone window provided excellent bone detail, however, the soft tissue components of the TMJ were not as well visualised using a soft tissue window. The articular cartilage was observed as a hyperattenuating stripe over the low attenuated subchondral bone and good delineation was obtained between cortex and medulla. The tympanic and petrous part of the temporal bone (middle and inner ear) and the temporohyoid joint were seen in close proximity to the TMJ. Conclusions: Helical CT provided excellent images of the TMJ bone components to characterise the CT anatomy of the normal joint. Potential relevance: Detailed information is provided that may be used as a reference by equine veterinarians for the CT investigation of the equine TMJ and serve to assist them in the diagnosis of disorders of the TMJ and related structures (middle and inner ear). The study was performed at an immature stage and further studies of mature individuals are required in order to confirm that the clinical interpretation is not affected by changes occurring with age.     

Clinically significant,nontraumatic, degenerative joint disease of the temporomandibular joints in a horse

Horses with degenerative joint disease (DJD) of the temporomandibular joint (TMJ) have been reported infrequently, with the majority of cases describing the disease as a consequence of an earlier traumatic event. A case of clinically significant TMJ‐DJD due to a nontraumatic event has not been published. This retrospective case report describes a case of bilateral, DJD of the TMJ. Case management, subsequent review and interpretation of the clinical records, tangential radiographic views of each TMJ, computed tomography and magnetic resonance imaging of the head, and post mortem histological examination of the TMJs were performed. The horse exhibited both quidding and a ‘clicking’ sound during mastication; episodes of intermittent colic were also prevalent in the horse's history. Computed tomography illustrated bilateral mineralisation of the rostral aspect of both intra‐articular discs. Treatment, by intra‐articular injection of corticosteroid, resulted in temporary resolution of both the quidding and the ‘clicking’ sound, as well as the recurrent episodes of colic. Repeated treatment over time was required. Ultimately the horse was subjected to euthanasia for reasons other than disease of the TMJ. The development of TMJ‐DJD may not be confined to traumatic events. Age‐related degeneration of this joint may occur and manifest through quidding and abnormal sounds noted during mastication.     

Mandibular condylectomy and meniscectomy for the treatment of septic temporomandibular joint arthritis in a horse

OBJECTIVE: To report use of mandibular condylectomy for treatment of advanced degenerative joint disease of the temporomandibular joint (TMJ) caused by sepsis. DESIGN: Clinical case report. ANIMALS: Two-year-old Noriker filly. METHODS: Computed tomography (CT) was used to confirm advanced degenerative joint disease of the left TMJ and for follow-up after mandibular condylectomy and removal of necrotic meniscus. RESULTS: Painful swelling (3 weeks duration) with drainage located just caudal to the left lateral canthus of the eye was associated with atrophy of the left masseter muscle, masticatory problems, and inappetence. There was incisor malocclusion with a 1.4 cm resting lateral mandibular deviation to the right and inability to open the mouth more than a few centimeters. Left mandibular condylectomy combined with meniscectomy and thorough debridement of the septic left TMJ resulted in resolution of clinical signs and complete return of function. Streptococcus zooepidemicus, intermediately resistant to penicillin and subsequently to enrofloxacin, was isolated from the wound. Regeneration of a mandibular "pseudocondyle" was evident on CT at 4 months. At 4 months and 1 year the filly had maximal mouth opening >10 cm and no malocclusion. CONCLUSION: Mandibular condylectomy can be used to facilitate management of septic TMJ arthritis. There was no radiologic or clinical evidence of TMJ ankylosis >1 year after meniscal removal. CLINICAL RELEVANCE: Mandibular condylectomy, including meniscectomy, is an acceptable treatment option for advanced TMJ septic arthritis and allowed return of normal masticatory function.     

Arthroscopic treatment of temporomandibular joint sepsis in a horse

OBJECTIVE: To report arthroscopic debridement and lavage of a septic temporomandibular joint (TMJ) in a horse. DESIGN: Clinical case report. ANIMALS: A 12-year-old Thoroughbred mare. METHODS: Arthroscopic investigation of the dorsal joint pouch of the right TMJ was made through a stab incision into the dorsocaudal compartment. Mechanized resection of synovium and fibrinous debris combined with copious lavage, and intra-articular and systemic antibiotic administration was used to treat the septic TMJ. RESULTS: Arthroscopic debridement and lavage of the TMJ, in combination with intra-articular and systemic antimicrobials resulted in resolution of sepsis. Eight months post-operatively, there was no clinical evidence of degenerative joint disease or ankylosis of the TMJ. CONCLUSION: TMJ sepsis is rare in horses, however, standard arthroscopic equipment can be used in the management of this condition with minimal complications. CLINICAL RELEVANCE: Arthroscopic debridement and lavage should be considered for evaluation and initial treatment of TMJ sepsis in horses.     

Arthroscopic treatment of bilateral mandibular condylar cysts and associated osteoarthritis of the temporomandibular joints in a horse

A horse was presented with a history of unpredictable behaviour under saddle to the point that the owner deemed the horse dangerous to ride. In addition, at rest the horse frequently protruded his tongue and during mastication a “clunking” sound could be heard. Radiographic examination at a previous clinic had revealed a normal left temporomandibular joint (TMJ) and a radiopaque mass in the right TMJ. However, despite arthroscopic surgery of the abnormal joint, the clinical signs had not resolved. Diagnostic investigation at the referral clinic revealed that TMJ analgaesia altered both a baseline hindlimb lameness and a behavioural component to the movement of the horse. Computed tomography (CT) illustrated the presence of bone cysts within the mandibular condyles and marginal osteophytosis of the discomandibular joints consistent with osteoarthritis. Arthroscopic examination, debridement of the affected joints and post-operative intra-articular injection of autologous protein solution resulted in temporary resolution of both the behavioural changes and the “clunking” sound. Ultimately, the horse was euthanised for continued dangerous behaviour, which treatment had failed to resolve in the longer term. In conclusion, the presence of cysts in the mandibular condyle and osteoarthritis can be a cause of abnormal behaviour, which may render a horse dangerous to ride. The case report illustrates the complex interaction between the TMJ, behaviour and movement.     

Arthrotomy,curettage and medical management of septic arthritis and osteomyelitis of the temporomandibular joint in a horse

Osteomyelitis and/or bone sequestra are commonly reported in equids following traumatic wounds. This report describes the clinical management and outcome following an arthrotomy of the temporomandibular joint of a 1-year-old Quarter Horse gelding with septic osteomyelitis and arthritis. Computed tomography was used for further assessment of the lesions within the temporomandibular joint and helped guide surgical planning.     

Fracture, luxation, and chronic septic arthritis of the temporomandibular joint in a juvenile horse

This case report describes chronic sepsis of the right temporomandibular joint in a juvenile horse. Diagnostic work-up included physical examination, radiography, and computed tomography. Humane euthanasia was indicated due to the chronicity of the condition, prognosis, and financial constraints.     

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.     

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.     

Idiopathic infectious arthritis of the coxofemoral joint in a mature horse

The authors are aware of only one previously described case of idiopathic infectious arthritis of the coxofemoral joint in a mature horse. The case described herein presented with clinical signs that localised pain to the proximal limb, subtle increased radiopharmaceutical uptake at the coxofemoral joint and an increase of the major acute phase protein, serum amyloid A in the horse's blood biochemistry. The latter finding led the authors to search initially for an infective process. Ultrasound guided aspiration of the coxofemoral joint yielded infected synovial fluid. Despite the duration of the condition, nonsurgical treatment allowed the horse to return to its previous, relatively modest, level of activity. This case is presented to supplement the single previously published case report of idiopathic adult coxofemoral infectious arthritis in the horse.     

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).     

Surgical repair of a chronic,oronasal fistula in a horse using an alveolar bone flap

An 8‐year‐old Andalusian stallion was presented to the Equine Hospital with a 1.5 year history of an oronasal fistula measuring approximately 2 cm long (caudal to rostral) by 1.5 cm wide following an oral extraction of the right second maxillary premolar (106). An alveolar bone flap was created adjacent to the oronasal fistula and rotated axially and ventrally to close the oral aspect of the fistula. At 3 days after surgery, clinical signs of the fistula, such as green‐tinged purulent nasal discharge and malodorous breath, were no longer evident. At 10 days after surgery, the oral opening of the fistula filled with granulation tissue and mucosa and decreased in size to less than 2 ml. The horse was fed a pelleted mash and grass diet and the small fistula was flushed orally twice daily until it completely healed. At 6 months following surgery, the fistula had completely healed. Few options are available for repairing an oroantral or an oronasal fistula in horses. This case report suggests that a large, chronic oronasal fistula involving the alveolus of a maxillary second premolar can be repaired successfully with an alveolar bone flap.     

Differences in the morphology of distal border synovial invaginations of the distal sesamoid bone in the horse as evaluated by computed tomography compared with radiography

Reasons for performing study: Distal border synovial invaginations of the distal sesamoid bone are radiographically assessed during the selection process of horses admitted as breeding stallions or in purchase examinations. Nowadays, many moderately or some deeply penetrating proximally enlarged synovial invaginations are considered as moderate or severe radiographic findings. Objective: To measure the difference between and agreement of the morphology of distal border synovial invaginations on radiography vs. computed tomography (CT). It was hypothesised that the morphology of distal border synovial invaginations would be better evaluable on CT compared with radiography. Methods: Computed tomography scans and 3 dorsoproximal–palmarodistal oblique (DPr‐PaDiO) radiographs were obtained on 50 cadaver forefeet from 25 Warmblood horses. Computed tomography was assumed to be the gold standard. The number, shape and depth of penetration of distal border synovial invaginations into the distal sesamoid bone were evaluated with both methods, and the comparison of their measurements was statistically described. Results: A statistically significant mean difference for number of distal synovial invaginations between CT and all 3 DPr‐PaDiO projections was found and was approximately equal to 2, meaning that CT permits visualisation of an average of 2 more invaginations than radiography. In none of the cases did radiography have a higher number observed than CT. A large variation in the difference of measurements for depth of penetration against their mean difference between CT and the 3 radiographic projections was seen. Radiography underestimated the depth of invaginations, and more so when these were deeper. There was no statistically significant mean difference found between the techniques for depth. A moderate to good agreement between measurements on CT and the three DPr‐PaDiO projections for shape was seen, in which the D55°Pr‐PaDiO projection showed the best agreement. A high specificity (90–99%) and low sensitivity (65%) for all projections for shape were found. Conclusions and potential relevance: Radiography differs considerably from CT concerning the morphology of distal navicular border synovial invaginations. For the evaluation of the number, depth and shape of distal synovial invaginations in the distal sesamoid bone, radiography shows only partially the morphology seen on CT.     

Computed tomographic features of the temporomandibular joint in 10 Jeju horses

BackgroundThe equine temporomandibular joint (TMJ) has a complex anatomical structure that makes diagnosis of TMJ disorders difficult. Computed tomography (CT) is now available in equine medicine; hence, TMJ evaluation has become more convenient.ObjectivesThe objectives of this study were to describe the CT features of the TMJ in Jeju horses and to compare these features with those of Thoroughbreds.MethodsIn this report, the TMJs of 10 Jeju horses (mean age: 4.5 ± 1.9 yr; mean body weight: 282.6 ± 40.3 kg) and 6 Thoroughbreds (mean age: 7.3 ± 1.6 yr; mean body weight: 479.7 ± 44.0 kg) were examined using CT. After CT scanning, the Hounsfield units (HU) and height to width ratio (H:W) of the mandibular condyle were measured.ResultsThe mean H:W in Jeju horses was significantly lower than that in Thoroughbreds. The mean HU in Jeju horses was lower than that in Thoroughbreds; however, the difference was not significant. The most frequent CT finding was an irregular medial margin of the mandibular condyle in both breeds.ConclusionsIn this study, the shape of the mandibular condyle in Jeju horses was flatter than that in Thoroughbreds. This report could be useful in evaluating the TMJ in Jeju horses. Moreover, CT could be a pragmatic choice for the examination of the TMJ in horses.     

Advanced imaging of a histologically confirmed bone infarction of the distal tibia in a Warmblood mare

An 8-year-old Warmblood-cross mare presented for investigation of acute onset left hindlimb lameness. Nuclear scintigraphy identified a marked, focal, increase in radiopharmaceutical uptake in the distal aspect of the left tibia. Radiography revealed a large, oval, multi-loculated radiolucent area within the medulla of the distal metaphysis of the left tibia. The mare was treated conservatively for 6 months but showed little improvement in the lameness so the owner elected for euthanasia. Post-mortem computed tomographic imaging revealed a large, oval, hypoattenuating area within the distal tibia, surrounded by a thick, irregular, sclerotic border. The lesion occupied the majority of the medullary cavity but the cortical bone was unaffected. Gross and histopathological examination confirmed a diagnosis of a bone infarction in the medullary cavity of the distal tibia.     

Treatment of a second carpal bone fracture by removal under ultrasonographic guidance in a horse

OBJECTIVE: To report an unusual 2nd carpal bone (C2) slab fracture and its treatment, using an ultrasonographically assisted, minimally invasive arthrotomy technique, for fragment removal. STUDY DESIGN: Case report. ANIMALS: An 11-year-old crossbred Warmblood gelding. METHODS: A bone fragment, spanning the height of C2, identified on the palmaromedial aspect of C2 was demarcated intraoperatively using ultrasonographically guided needles and removed by arthrotomy. RESULTS: Fracture fragment removal was achieved using a small, ultrasonographically guided arthrotomy. The horse has become sound after treatment and returned to the previous level of pleasure riding activity. CONCLUSIONS: Perioperative ultrasonography was used to delineate and facilitate removal of an unusual slab fragment of C2, through a minimally sized arthrotomy. Despite the presence of pancarpal osteoarthritis and partial involvement of the medial collateral ligament, the prognosis appeared to be satisfactory for this pleasure riding horse. CLINICAL RELEVANCE: Ultrasonographic guidance may be used to optimize the approach to C2 articular bony fragments that may not be observed using arthroscopy.