Partial mandibular condylectomy and temporal bone resection for chronic,destructive, septic arthritis of the temporomandibular joint in a horse

Sepsis of the temporomandibular joint (TMJ) of the horse is rare. This case report describes the use of radiography, ultrasonography and computed tomography to diagnose sepsis of the TMJ in a 2‐year‐old Thoroughbred filly. The mandibular condyle and temporal bone were partially resected to successfully remove necrotic tissue within and surrounding the TMJ. Sepsis resolved and the horse returned to race training. Follow‐up computed tomography examination showed generation of a mandibular ‘pseudocondyle’ at 8 months post operatively.     

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.     

Does temporomandibular joint pathology affect performance in an equine athlete?

Temporomandibular joint (TMJ) pathology is a rarely reported cause of decreased performance among equine athletes or at least seldom recognised. This case report describes the work‐up of a high level dressage horse with decreased performance. Temporomandibular joint pathology was suspected based on computed tomography (CT) and the horse responded very well to joint treatment.     

Is there a relationship between clinical presentation,diagnostic and radiographic findings and outcome in horses with osteoarthritis of the small tarsal joints?

Reasons for performing study: Despite the possibility that sound horses may have radiographic signs consistent with osteoarthritis of the small tarsal joints (OA‐STJ), a diagnosis of ‘bone spavin’ as a cause of lameness is often made based only on radiographic examination. Objectives: To determine whether severity of radiographic change and response to treatment are correlated with the duration and degree of lameness and the response to intra‐articular anaesthesia in horses with OA‐STJ. Methods: A retrospective study of all horses that showed a positive response to intra‐articular anaesthesia of the STJ was performed. Details of history, clinical presentation and diagnostic findings were recorded. Radiographs of affected tarsi were evaluated and scored independently by 2 observers. Follow‐up was via a telephone questionnaire with the owner. Statistical analysis was used to assess the association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings. Response to treatment was compared with the findings from the diagnostic work‐up. Results: Ninety‐one horses were included (61 unilateral and 30 bilateral lameness). Fifty‐nine percent of horses had been lame for over 2 months. There was no association between the duration and degree of lameness, or between duration or degree of lameness, intra‐articular anaesthesia and radiographic findings. Response to treatment showed a significant positive association with less severe radiographic changes within the tarsometatarsal (TMT) joint. Follow‐up was available for 48% of cases, with 52% horses returning to the same level of exercise. Conclusions: There is no association between the duration and degree of lameness, the response to intra‐articular anaesthesia and radiographic findings in horses with OA‐STJ. However, horses that improved following treatment tended to have less marked TMT joint pathology. Potential relevance: Response to intra‐articular anaesthesia should remain the gold standard for diagnosis of OA‐STJ. Predicting which cases are likely to improve following treatment remains difficult.     

Arthroscopic treatment for cervical articular process joint osteochondrosis in a Thoroughbred horse

A yearling Thoroughbred colt was presented for investigation of neck stiffness and episodes of intermittent neck pain without neurological signs. Osteochondrosis (OCD) of the cervical articular process joints (APJs) was diagnosed with the aid of radiography and computed tomography. An articular osteochondral fragment of the left fourth caudal cervical articular process was removed arthroscopically following a cut down approach to the joint capsule of the affected APJ. Surgical removal resulted in resolution of clinical signs at 4 weeks. However, subsequently the horse was markedly ataxic 6 weeks post surgery after being found cast in its stable. Cervical stenotic myelopathy was considered the most likely cause based on clinical and radiographic signs and the horse was subjected to euthanasia due to a poor prognosis for racing. Post‐mortem examination identified atypical cartilage within several cervical APJs with histological changes consistent with OCD. This case report supports OCD of the APJs as a cause of neck pain and confirms the clinical practicality and short‐term effectiveness of arthroscopic fragment removal. Surgical treatment for cervical OCD should be considered in horses without neurological signs, although case selection is important and the underlying pathology remains a risk factor for the development of subsequent neurological signs.     

Temporomandibular ankylosis in the cat: a review of seven cases

Ankylosis of the temporomandibular joint (TMJ) in the cat is an unusual complication of traumatic lesions involving articular (true ankylosis) or periarticular structures (false ankylosis). Seven cats with true ankylosis of the TMJ (four cases unilateral and three cases bilateral), of which previous trauma had been documented in five cases, were referred to the authors' clinic between September 1991 and October 1996. Radiographic assessment was performed in all cases, using dorsoventral and oblique projections. Five subjects underwent arthroplastic excision of the TMJ and, in the remaining two cases, stretching of the jaws was performed under general anaesthesia. The surgical outcome was satisfactory in all but one case, where partially decreased joint mobility was observed (follow-up time one to five years), but in the two cases where non-surgical treatment was carried out, recurrence of TMJ ankylosis was observed (follow-up time two to five months). In the authors' experience, surgery represents the treatment of choice for TMJ ankylosis in cats. Additional mandibular symphysiotomy can confirm the radiological findings in unilateral cases.     

Idiopathic haemarthrosis in eight horses

Objectives To review eight horses diagnosed with idiopathic haemarthrosis and to describe the intra‐articular use of yttrium‐90 (⁹⁰Y) and methylprednisolone acetate (MPA) in recurrent haemarthrosis cases. Design Retrospective case series. Method The medical records, diagnostic images, histopathology and outcome of all horses diagnosed with idiopathic haemarthrosis between 1998 and 2010 were reviewed. Results Four Thoroughbred racehorses with haemarthrosis of the antebrachiocarpal joint had severe acute lameness (median, grade 4) and marked joint effusion after high‐speed exercise. Another four horses (2 Thoroughbred racehorses, 1 Standardbred racehorse, 1 Warmblood) had haemarthrosis of the tarsocrural joint and presented with mild, intermittent lameness (median, grade 1) and marked, persistent joint effusion. Six of the eight horses had recurrent haemarthrosis prior to treatment. Radiographic and nuclear scintigraphic examinations did not identify bone pathology. Diagnostic arthroscopy (7 cases) identified grossly hypertrophied yellow/brown discoloured synovium. Synovial histopathology of these cases revealed chronic synovial hyperplasia with severe haemosiderosis and granulomatous inflammatory reaction of varying severity. All horses underwent rest, bandaging and phenylbutazone administration. Two horses had subtotal mechanical synovectomy, four horses had intra‐articular administration of ⁹⁰Y and MPA, and one horse underwent both treatments. Seven cases returned to their previous use (median time, 7 months). Haemarthrosis recurred in three horses, two of which had received the ⁹⁰Y and MPA treatment. Conclusion Idiopathic haemarthrosis should be considered a differential for acute and recurrent joint related lameness and effusion. Recurrence appears not uncommon and the use of intra‐articular ⁹⁰Y and MPA in conjunction with a conservative management treatment protocol warrants further evaluation.     

NAVICULAR BONE FRACTURE IN THE PELVIC LIMB IN TWO HORSES

The case history, radiographic and scintigraphic findings of two horses with pelvic limb navicular bone fractures are presented. In both cases the fractures were of traumatic origin. One horse had a bilateral fracture of the navicular bone, distal border, the other horse had a fracture of the proximal articular border in one pelvic limb navicular bone.     

Osteochondral fragmentation of the palmarolateral/plantarolateral aspect of the distal phalanx in four horses: A novel location

Four horses presenting for lameness were diagnosed with unilateral osteochondral fragmentation (OCF) of the palmarolateral/plantarolateral aspect of the distal phalanx within the distal interphalangeal joint (DIPJ). Histological evaluation of one case supported a diagnosis of osteochondritis dissecans (OCD), with patient age and history from two cases suggesting a traumatic origin. Lesion appearance on conventional radiography, computed tomography (CT), nuclear scintigraphy and magnetic resonance imaging (MRI) are described. Fragmentation was best identified on dorsal 65° proximal-palmaro/plantarodistal oblique (D65°PrPDiO/D65°PrPlDiO) and dorsal 65° proximal-palmaro/plantarodistal lateral oblique (D65°Pr45°L-PDiMO/D65°Pr45°L-PlDiMO) radiographic projections of the foot, but articular pathology appeared more severe on cross-sectional imaging modalities. In all cases, lameness was refractory to conservative management. Arthroscopic evaluation of the DIPJ was performed in three horses, although the lesion was inaccessible in two. In one horse, access to the lesion was possible due to increased joint laxity, presumably due to concurrent soft tissue injury. One horse was euthanased after failed conservative management, one was pasture sound following palmar digital neurectomy 12 months after initial presentation, one returned to racing and one was lost to follow-up. Osteochondral fragmentation at this location has not previously been described, treatment options are limited and the prognosis appears to be poor.     

Recent advances in articular cartilage evaluation using computed tomography and magnetic resonance imaging

Articular cartilage is a critical joint tissue and its evaluation remains a diagnostic challenge in horses. Coupled with a poor capacity for healing, early degenerative changes in articular cartilage are difficult to characterise using routine diagnostic imaging evaluations. Both computed tomography (CT) and magnetic resonance imaging (MRI) provide volumetric joint assessment and highlight morphological and quantitative properties of articular cartilage, improving assessment of this essential tissue. While the use of CT and MRI for joint evaluation is not new, there still remains a shortage of literature and scientific studies on the ability of these methods to evaluate articular cartilage in the horse. This review article summarises current CT and MRI techniques capable of characterising equine articular cartilage, highlights recent advances in these techniques and discusses the numerous methods studied in human subjects that have been minimally investigated in horses. Imaging techniques are presented in terms of their capabilities of offering morphological and quantitative evaluation along with a discussion of their benefits and limitations. Finally, it summarises the current state‐of‐the‐art approaches and identifies unmet clinical imaging needs to propel the advancement of articular cartilage and joint imaging in the horse.     

Absence of the Articular Disc in the Tasmanian Devil Temporomandibular Joint

The articular disc of the temporomandibular joint is a constant structure in mammals. According to Parsons' report in 1900, however, it is absent in four animals: the armadillo, two kinds of monotremes and the Tasmanian devil. Thereafter, no research was performed to confirm this observation. The aim of this study was to determine by anatomical and histological examination whether the Tasmanian devil has an articular disc in its temporomandibular joint. Six fresh frozen corpses and one dry skull of Tasmanian devils were obtained from the School of Zoology, University of Tasmania. The corpses were dissected and the morphology of the temporomandibular joint was carefully observed by gross anatomical and histological examination. The structure of the temporomandibular joint of the dry skull was examined macroscopically and by micro‐computed tomography. In all cases, absence of the articular disc in the Tasmanian devil temporomandibular joint was morphologically confirmed. The surface layer of both the condyle and the glenoid fossa comprised a thick fibrous tissue. Micro‐computed tomography revealed dense and fine trabecular bone in the condyle. The thick fibrous tissue covering the condyle and high‐density trabecular bone in the condyle might play a role in absorption against powerful mastication and heavy loading of the Tasmanian devil temporomandibular joint.     

Progression of radiographic evidence of osteoarthritis following tibial plateau leveling osteotomy in dogs with cranial cruciate ligament rupture: 295 cases (2001-2005)

OBJECTIVE: To determine whether radiographic signs of osteoarthritis became progressively worse and tibial slope angle (TSA) changed substantially following tibial plateau leveling osteotomy for treatment of cranial cruciate ligament rupture in dogs. DESIGN: Retrospective case series. ANIMALS: 295 dogs (373 stifle joints). PROCEDURES: Medical records were reviewed. Radiographs obtained before and 8 weeks after surgery were used to determine the degenerative joint disease (DJD) score, calculated as the sum of individual scores (0 through 3) assigned to 30 radiographic factors. Radiographs obtained immediately and 8 weeks after surgery were used to measureTSA. For dogs that underwent bilateral surgery, data for the first joint treated were used in analyses. Data for the second joint treated in dogs that underwent bilateral surgery were analyzed separately. RESULTS: A small, but significant, increase was found in mean DJD score 8 weeks after surgery, compared with mean preoperative score. An inverse relationship was found between preoperative DJD score and the difference between postoperative and preoperative DJD scores. Mean TSA 8 weeks after surgery was significantly higher than mean TSA immediately after surgery. Analysis of data for the second stifle joints in the 78 dogs that underwent bilateral surgery yielded similar results. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that there was a small, but measurable, increase in the severity of radiographic changes attributed to osteoarthritis in the stifle joints of dogs that underwent tibial plateau leveling osteotomy because of cranial cruciate ligament rupture.     

Osteochondral dysplasia of the coxofemoral joints in a Friesian foal: Clinical findings and methods of diagnosis

Diseases of the coxofemoral (hip) joint are infrequently diagnosed in horses. Most cases are presented as an unilateral condition and usually are of traumatic origin. This case report describes a Friesian foal with a clinically obvious thoracolumbar kyphosis, combined with a weight‐shifting stance and a shortened stride of both hindlimbs. General clinical and lameness examinations, computed tomographic examination of the pelvis, and macroscopic and histopathological examinations of the coxofemoral joints were performed. This revealed a final, phenotypical diagnosis of a primary osteochondral dysplasia of both coxofemoral joints with secondary osteoarthritis. Similar to the occurrence of this condition in other species and considering the small genetic basis of the Friesian horse breed, a genetic predisposing factor is suspected to play a key role in the developing mechanism of dysplastic coxofemoral joint disease in horses as illustrated with this case. Computed tomography scanning appears to be a useful imaging technique in the detection of coxofemoral joint disease in small horses and foals.     

Primary degenerative joint disease of the shoulder in a colony of beagles

Shoulder joints of 149 Beagles over 8 years old at the time of death (mean age, 13.8 years +/- 3.21), were examined radiographically throughout their life-times for the frequency of degenerative joint disease (DJD). Clinical histories revealed no underlying cause for DJD. The shoulder joints of a subgroup of 18 dogs were examined at necropsy, and thin sections of the joints were evaluated radiographically and histologically. Serial clinical radiographic studies indicated that normal shoulder joint development during the first year of life was followed by the appearance of subchondral bone sclerosis and bony remodeling of normal joint contour, and by the formation of periarticular osteophytes and enthesiophytes. All changes were progressive with age and typical for DJD in dogs. Bilateral involvement was common. Evaluation of specimens obtained at necropsy revealed: articular cartilage change with roughening of the surface layer, degeneration and death of superficial chondrocytes, exposure of deeper layers of chondrocytes that had proliferated with fissuring of the damaged cartilage, total cartilage loss with polishing of the exposed subchondral bone, mixed patterns of subchondral bone sclerosis and osteoporosis, change in contour of the articular surfaces, and formation of periarticular osteophytes and enthesiophytes. Joint capsule thickening, synovitis, pannus formation, and synovial chondroma formation were observed. Because of the available clinical information, in addition to the typical changes of DJD, it was thought that the changes were primary. Instability appeared to play a role in the pathogenesis of the joint disease described; however, it was not clear whether the instability caused abnormal forces on healthy cartilage or whether the primary cartilage wear caused the instability.     

Intraaticular treatment of tarsal degenerative joint disease in cattle.

Tarsal degenerative joint disease (DJD) in 12 cattle was classified as primary or secondary, based on age, evidence of hereditary or congenital joint conformation defects, faulty hindlimb alignment, duration and type of usage joints were subjected to, and history or signs of repeated trauma. Three of the cattle had bilateral primary tarsal DJD, 7 had bilateral secondary tarsal DJD, and 2 had secondary DJD of the left tarsus. Analyses of synovial fluid samples provided a means of characterizing pathologic changes of tarsal DJD, Results of blood and synovial fluid analyses were grouped in compilation of data for cattle affected with either primary or secondary tarsal DJD. Corticosteroids and a long-acting synthetic progestational agent were injected singly or in combination with aqueous antibiotics into affected tarsal joints. Tarsal joints of 5 of the cattle responded favorably to a single intraarticular treatment, as manifested by palliative relief and functionally usable joints. Seven joints of 5 cattle were subjected to repeated intraarticular treatment. Serial synovial fluid analyses in 7 of the cattle provided a means of assessing tarsal joint response to intraarticular treatment or to therapeutic arthrocentesis, exclusive of patient objective response. One cow developed a mild self-limiting bilateral postinjection synovitis that was resolved after the 2nd and final intraarticular injection. Usable function returned to tarsal joints of cattle that responded favorably to intraarticular treatment at different periods after single or repeated injections. Three cattle with advanced tarsal DJD experienced minor temporary relief and were euthanatized at their owner's request. Improvement did not occur in the tarsal joint of 1 cow subjected to therapeutic aspiration only. Intraarticular treatment in all cattle was considered supportive to the animal's well-being rather than curative.     

Dorsomedial articular fracture of the proximal aspect of the third metacarpal bone in standardbred racehorses: seven cases (1978-1990).

Seven Standardbred horses, all pacers, with a mean age of 2.9 years (range, 2 to 4 years), had dorsomedial articular fracture of the proximal aspect of the third metacarpal bone. Fracture caused acute, unilateral, severe lameness after training or racing. Lameness was abolished by midcarpal joint anesthesia in 4 horses. Six horses had a palpable bony swelling, which caused signs of pain. Radiography revealed a nondisplaced, articular, oblique fracture extending distad toward the dorsomedial cortex for a mean distance of 28 mm (range, 15 to 40 mm). In all horses, chronic periosteal proliferative changes, seen near the distal aspect of the fracture, corresponded to palpable bony exostoses and were associated with the medial attachment of the extensor carpi radialis tendon. In 1 horse, internal fixation followed by a 6-month rest resulted in a successful outcome. All other horses were given 3 months' rest without surgery and were not lame. Five horses raced successfully and lowered the lifetime race records, 1 horse was sound and trained successfully, but died of colic, and 1 horse was not lame in early training.     

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.     

Vacuum phenomenon in the metatarsophalangeal joint of a horse

Vacuum phenomenon was induced inadvertently during radiographic examination of a metatarsophalangeal joint of a lame horse. The phenomenon was recreated in a sound horse when a metacarpophalangeal joint was radiographed in a stress-flexed position. Distraction of apposing articular surfaces may induce the vacuum phenomenon, which could result in misdiagnosis of an osteochondral defect or fracture.