Evaluation of Experimental Transection and Partial Excision of the Caudal Cruciate Ligament in Dogs

The caudal cruciate ligament (CaCL) of one stifle joint in seven dogs was transected and a 2 to 4 mm section was removed. Six months after surgery, none of the dogs were lame. Thigh muscle circumference, stifle range of motion, and internal tibial rotation in the operated limb were not significantly different from the preoperative measurements or the contralateral, unoperated limb. A caudal drawer motion was consistently present in the stifle joints with a transected CaCL. A radiographic evaluation of the operated stifle joints did not reveal osteoarthritic changes; four of seven stifle joints had an irregular fat pad 6 months after surgery. Results of a joint fluid analysis revealed a slight increase in synovial cells within treated stifle joints; inflammatory cells were not observed. The only gross morphologic change in stifle joints with a severed ligament was enlarged knobby remnants of the CaCL. Articular cartilage defects or osteophytes were not observed. Results of a histologic examination of the CaCL remnants revealed synovial cellular capping and intraligamentous fibroplasia. Based on a limited number of dogs, it was concluded that isolated transection of the CaCL produced minimal clinical and pathologic changes in the stifle joint during a 6 month period.     

Prevalence of fragmented medial coronoid process of the ulna in lame adult dogs

Over a period of three years, a diagnosis of fragmented medial coronoid process of the ulna was confirmed by arthroscopy in 263 dogs, in 69 of which both elbow joints were affected, giving a total of 332 affected joints; 39 of the joints were also affected by osteochondrosis dissecans of the trochlea of the humerus. More than half of the dogs (51.7 per cent) were over one year old when first examined. In 259 (78 per cent) of the joints there were radiographic changes of secondary osteoarthrosis of different severity, but the other 73 (22 per cent) had no signs of osteophytosis except for a mild sclerosis. Among these 73 there were 14 joints in 13 dogs between 19 and 36 months old and 11 joints in 10 dogs over three years old. A further 12 joints in 11 dogs over three years old showed only mild arthrosis. In five of the 11 joints of the dogs over three years old which had no radiological signs of arthrosis, the fragment was already dislocated. Among the dogs over 18 months old with no arthrosis and the dogs over three years old with mild arthrosis, the most commonly affected breeds were the Bernese mountain dog, rottweiler and boxer.     

Radiological Evaluation of Juvenile osteochondral Conditions in Brazilian Warmblood Horse

The term juvenile osteochondral condition (JOCC) has been used to identify developmental changes in the growth plates. The condition is characterized by a set of changes with similar pathogenesis that affect the immature skeleton and joints of growing foals. The aim of the current study is to investigate the prevalence and degree of severity of osteochondral changes in Brazilian warmblood (BW) foals in two farms in the south of Brazil. Radiological evaluation was applied to the metacarpophalangeal (MCP), carpal (C), metatarsophalangeal (MTP), tarsal (T), and femorotibiopatellar (FTP) joints of 90 foals (47 females and 43 males) in the age group 16–36 months. The evaluation was made before the animals started their athlete performance. Changes were classified as a degree of severity 0 to 4. Changes were diagnosed in 56 foals (58%) that had 105 affected joints. Thirty-three (59%) out of the 56 animals had changes in more than one joint; 57% (19/33) of them had bilateral changes. MTP and MCP were the joints with the most severe changes, respectively (severity 2 and 3), followed by FTP, T, and C. Osteochondral fragments (59%), tarsal arthropathies (48%), irregularities and radiolucency in the FTP joint (7%), and subchondral cystic lesion in the FTP joint (1%), were the most observed changes. BW foals recorded the high prevalence of osteochondral alterations; although MTP and T were the most affected joints, MTP and MCP presented the most severe changes. The present study confirmed significant JOCC prevalence in BW. Further studies should be carried out in different properties.     

Biochemical analysis of the articular cartilage and subchondral and trabecular bone of the metacarpophalangeal joint of horses with early osteoarthritis

OBJECTIVE: To assess whether site-related changes in biochemical composition are present in the cartilage and subchondral and trabecular bone of the metacarpophalangeal joint of horses with early osteoarthritis. SAMPLE POPULATION: Right metacarpophalangeal joints from 59 mature warmblood horses. PROCEDURE: Biochemical data (cross-link, amino acid, DNA, and ash contents; denatured collagen and glycosaminoglycan [GAG] concentrations; bone mineral density; and mineral composition) were obtained from 2 differently loaded sites of phalanx I cartilage and subchondral and trabecular bone samples; data were compared with previously published values from nonosteoarthritic equine joints. RESULTS: Compared with findings in nonosteoarthritic joints, GAG concentration was lower in cartilage from osteoarthritic joints and there was a loss of site differences in cellularity and lysylpyridinoline (LP) cross-link content. In subchondral bone, LP cross-link content was decreased overall and there was a loss of site differences in osteoarthritic joints; ash content was higher in the osteoarthritic joints. Hydroxyproline content in trabecular bone from osteoarthritic joints was greater than that in nonosteoarthritic trabecular bone. In all 3 layers and at both sites, the linear increase of the pentosidine cross-link content with age had diminished or was not apparent in the horses with osteoarthritic joints. CONCLUSIONS AND CLINICAL RELEVANCE: In equine metacarpophalangeal joints with early osteoarthritis, distinct biochemical changes were detected in the cartilage and subchondral and trabecular bone. The dissimilarity in response of the different tissues and differences between the sites that are affected may be related to differences in biomechanical loading and transmission and dissipation of force.     

Cross-sectional study of the prevalence and clinical features of osteoarthritis in 100 cats

To assess clinical signs and relevance of osteoarthritis (OA) in cats, the radiographic prevalence of OA in the appendicular skeleton of 100 client-owned cats (?6 years old) was assessed. Possible associations between radiographic OA, clinical locomotor system examination, and owner-perceived behavioural changes were evaluated. OA was most prevalent in the shoulders, elbows, hips and tarsal joints with 61% of cats having OA in at least one joint and 48% in more than one joint. Overall, clinical examination of the larger peripheral joints had the highest sensitivity and specificity for radiographic OA. Regression analysis showed age to be related to OA (P = 0.002), as were decreased mobility and grooming (P = 0.008), although there was a correlation with age. Finally, increased inappropriate elimination was associated with OA (P = 0.046). It was concluded that the prevalence of OA in cats is strikingly high and increases with age. OA in cats seems to be associated with behavioural changes.     

Studies on the Bacterial Flora of Condemned Portions from Arthritic Hogs

Studies were conducted on the bacterial floral of 122 excised joints and related iliac and inguinal lymph nodes, 118 whole hams and 42 shoulders from condemned arthritic hog carcasses. Erysipelothrix insidiosa was isolated from 15% of the joints and lymph nodes, 20% of the hams, and 33% of the shoulders. Beta-hemolytic streptococci were recovered from 12% of the joints and lymph nodes, 49% of the hams, and 54% of the shoulders. Staphylococcus aureus was found in 3% of the joints and lymph nodes, 16% of the hams and 14% of the shoulders. Gross tissue changes were not pathognomonic for any causative organism.     

Pathological and histopathological findings in the joints of fattening turkeys

This paper reports on pathological and histopathological findings in the joints of male turkeys (B.U.T. Big 6) reared in two different housing systems. Pathological investigations were conducted on all animals which died between the 6th week of life and the end of fattening (585 birds, 1170 hip, knee and intertarsal joints) from four fattening periods with 3000 birds each. This study included 297 birds kept in a conventional housing system (barn 2) with a stocking density of 2.8 birds/m2, and 288 birds from a barn (1) from which the animals had access to an outdoor scratching area (stocking density 2.5 birds/m2). In all, 157 (26.5%) of the 585 fallen turkeys (barn 1:93; barn 2:70) showed at least one pathological joint alteration. and there were macroscopically detectable changes in 274 (7.8%) of the 3510 investigated joints: 152 (7.8%) of the 1728 joints from barn 1, and 122 (8.8%) of the 1782 from barn 2. In both housing systems the most frequent pathological alterations were in the intertarsal joint affecting 16% (188) of these 1170 joints (barn 1:106; barn 2:82); next most frequent were changes in the knee joint with 4.5% (53) of the 1170 joints affected (barn 1:26; barn 2:27). In both barns, synovial alterations occurred predominantly in the intertarsal and the knee joints. Bacteriological investigation of altered synovial fluids (83) most frequently showed an infection with Staphylococcus spp. (44) and E. coli (15). Macroscopic investigation showed alterations in 31 (2.7%) of the 1170 hip joints (barn 1:19; barn 2:12); 2% (22) of these showed cartilage degenerations of the femoral head (barn 1:15; barn 2:7). Histological investigation of these cartilage lesions showed that they were predominantly (70%) due to osteochondrosis with complete epiphyseolysis affecting 16 femoral heads (barn 1:10; barn 2:6). Partial epiphysiolysis was found in 24% (5) of the femoral heads (barn 1:4; barn 2:1). Furthermore, 43% (9) of the 22 femoral heads with cartilage degeneration also had osteomyelitis and osteochondritis, as well (barn 1:6; barn 2:3). Histological investigation of the 104 femoral heads with no macroscopic findings (barn 1:56; barn 2:48), revealed osteochondrosis in 11 cases (10.6%) (barn 1:6; barn 2:5). Osteomyelitis and osteochondritis were found in 17 (16.3%) of these femoral heads (barn 1:9; barn 2:8). There were no significant (p < 0.05) differences between the two housing systems in the incidence and frequency of joint alterations. It is to be assumed that these joint alterations were the cause of acute, chronic pain.     

RADIOGRAPHIC AND COMPUTED TOMOGRAPHY FINDINGS IN BELGIAN SHEPHERD DOGS WITH MILD ELBOW DYSPLASIA

We compared computed tomography (CT) and radiographic findings of Belgian shepherds with grade 1 or borderline elbow dysplasia to determine whether the radiopaque area dorsal to the anconeal process and seen in mediolateral 45° flexed radiographs is formed by osteophytes, or whether it is an anatomic variation. Eighteen dogs with screening results 0/1, 1/0, or one or both elbows graded as borderline were studied. The radiographs were evaluated according to International Elbow Working Group guidelines and compared with CT images. A fragmented medial coronoid process was seen in five joints, and remaining 31 joints were considered free of dysplasia based on CT images. In radiographs, height of the radiopaque area on the anconeal process was 0–2.7 mm in dysplastic and 0–3.0 mm in other joints. Sensitivity of this sign as dysplasia indicator was 40% and specificity 29%. All dysplastic joints and three of the other joints had blurring of the cranial edge of the medial coronoid process. Subtrochlear sclerosis was seen in four dysplastic joints and in three other joints. Both changes were significant indicators of dysplasia ( P <0.001). Sensitivity and specificity of these phenomena as dysplasia indicators were 80% and 90%, respectively. We conclude that the radiopaque area on the anconeal process might not always be osteophyte formation in Belgian shepherds and should not be used as the sole criterion for dysplasia. Blurring of the medial coronoid process cranial edge and ulnar trochlear notch sclerosis are reliable signs of elbow dysplasia and may be beneficial in screening protocols.     

Detection of synovial macrophages in the joint capsule of dogs with naturally occurring rupture of the cranial cruciate ligament

OBJECTIVE: To test the hypotheses that the densities of macrophages in the synovial membranes and capsules of stifle joints in dogs with ruptured cranial cruciate ligaments are greater than those of normal joints and that those densities in affected joints are positively correlated with the chronicity and severity of the disease. ANIMALS: 17 dogs with naturally occurring rupture of the cranial cruciate ligament and 5 healthy control dogs. PROCEDURE: All dogs underwent orthopedic and radiographic evaluations. In affected dogs, duration of clinical signs was used as an indicator of disease chronicity and the severity of osteoarthritis in the stifle joint was determined radiographically. Joint capsule specimens were evaluated histologically; macrophages, interleukin-6, and tumor necrosis factor-alpha were identified by use of immunocytochemical techniques. RESULTS: Compared with unaffected joints, macrophage density was increased in all affected joints. Duration of disease was significantly associated with radiographic severity of osteoarthritis and synovial macrophage density. Synovial macrophage density was significantly associated with severity of osteoarthritis and with the presence of interleukin-6 and tumor necrosis factor-a. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that synovial macrophages may be involved in the development of pathologic changes (including osteophyte formation) in the stifle joints of dogs with osteoarthritis secondary to rupture of the cranial cruciate ligament. Determination of the importance of synovial macrophages in the development of changes in osteoarthritic joints may result in new treatment strategies that involve elimination of the deleterious effects of those cells.     

Arthroscopic Surgery for the Treatment of Osteochondritis Dissecans in the Equine Femoropatellar Joint

Forty limbs with femoropatellar osteochondritis dissecans in 24 horses were treated with arthroscopic surgery. Lesions were bilateral in 16 horses and unilateral in eight horses. Diagnostic examination and surgical treatment were performed through a single arthroscopic portal; five different instrument portal locations and six instrument approaches were used. Lesions were localized to the lateral trochlear ridge of the femur in 31 affected joints, medial trochlear ridge in two joints, lateral and medial trochlear ridges together in two joints, lateral trochlear ridge plus patella in four joints, and patella alone in one joint. The lesions consisted of subchondral defects containing chondral or osteochondral flaps or fragments, or were seen as dimpling, cracking, fibrillation, or erosion of articular cartilage, or intact cartilage over a subchondral defect. Loose bodies were found in three joints. There was a poor correlation between radiologic and arthroscopic findings. Surgical manipulations included removal of flaps, fragments, and undermined articular cartilage, and debridement of the subchondral defect. Three horses were euthanized: one electively to assess the joint grossly, one because of complications following surgery and salmonellosis, and one because of unrelated forelimb abnormalities. Immediate clinical improvement after surgery was seen in the 22 horses permitted to survive. Long-term follow-up on seven of 10 racehorses revealed that two have raced successfully, two are "ready to race," three are training sound, two are sound at pasture (still in convalescence), and one has been reoperated. Of six horses used for show or pleasure, three are being shown sound, one is sound for pleasure, and two are training sound. The remaining horses are convalescing.     

A phalangeal fusion defect and osteochondrosis dissecans with subluxation of the distal interphalangeal joints in a foal

A fusion defect of the proximal and middle phalanges of both hindlimbs, osteochondrosis dissecans of the distal interphalangeal joints of the forelimbs, and subluxation of all 4 distal interphalangeal joints occurred in a Standardbred filly. Lameness was the first abnormality noted and was observed at one week of age in the left forelimb and progressed until all 4 limbs were affected by 5 weeks of age. On radiographs of both forelimbs, the distal interphalangeal joints were subluxated with irregularity and lucency of subchondral bone. On radiographs of the distal hindlimbs, there was a subluxation of both distal interphalangeal joints and loss of the proximal interphalangeal joint spaces with fusion of the proximal and middle phalanges. The foal was euthanised. On necropsy, there were focal areas of erosion of articular cartilage in the distal interphalangeal joint of both forelimbs. The proximal and middle phalanges of both hindlimbs were fused. Histopathological examination of the distal interphalangeal joint of the right foreleg showed loss of articular cartilage and degenerative changes in the exposed subchondral bone.     

Autologous processed plasma: cytokine profile and effects upon injection into healthy equine joints

This experimental controlled study was performed to evaluate the composition of autologous processed plasma (APP), and the effects of APP intra-articular injection into healthy equine metacarpophalangeal joints. The effects on joints were analysed with a short-phase protocol and a prolonged-phase protocol using saline-injected joints as controls. For the short protocol, horses received one intra-articular APP injection. Synovial fluid samples were collected prior to the injection and 3, 6, 24, 48, and 16 h after treatment. For the prolonged protocol, the joints received three weekly injections of APP, and samples were collected at 0, 7, 14, 21, and 28 days before APP administration. IL1-ra level was found to be increased in APP compared to plasma. Upon intra-articular administration of APP, transient (up to 24 h) increases in white blood cell (WBC) counts along with elevated protein and prostaglandin E₂ (PGE₂) concentrations were observed in the treated joints. Over the 28-day observation period, APP did not elicit changes relative to baseline levels, but WBC counts, PGE₂ and chondroitin sulphate concentrations were lower than those found in the control. In conclusion, APP intra-articular injection induced a mild and transitory inflammatory response but no inflammation reaction was observed over a longer period of treatment and observation.     

The influence of corticosteroids on sequential clinical and synovial fluid parameters in joints with acute infectious arthritis in the horse

Infectious arthritis was induced experimentally in one tarsocrural joint of six horses by intra-articular injection of 1 ml Staphylococcus aureus-saline suspension with the addition of 200 mg methylprednisolone acetate. The corresponding contralateral joint was injected with 1 ml of saline with the addition of 200 mg methylprednisolone acetate, and served as a control. The purpose of the experiment was to examine the effect of corticosteroids on the acute clinical signs of infectious arthritis, and the associated changes in synovial fluid, to separate the effects of a steroid injection from those of infection alone. This should aid early diagnosis of infection. The progression of the infectious arthritis was assessed over nine days by clinical examination and sequential synovial fluid analysis. The corticosteroids masked the clinical signs in some horses for up to the third day although changes in the synovial fluid were present earlier. Cellular changes preceded biochemical changes initially. Leucocyte counts showed a significant increase in cell numbers after infection was established. Persistent neutrophilia, over 90 per cent, together with a pH under 6.9 were the most consistent findings in the infected synovia. Total protein values were lower in infected joints with, than those without, corticosteroids; although there was a progressive rise in total protein concentration throughout the experiment in both groups. Serum and synovial glucose difference and synovial lactate had very little diagnostic value because significant increases due to the corticosteroids were documented in the control joints.     

Computed tomographic evaluation of growth-related changes in the hip joints of young dogs

OBJECTIVE: To evaluate changes in canine hip joint characteristics during growth via computed tomography (CT) and compare CT features of hip joints with and without laxity in young dogs placed in 2 imaging positions. ANIMALS: 21 dogs (42 hip joints). PROCEDURES: From 2 to 12 months after birth, CT examinations of the acetabulum of each hip joint in simulated normal standing and simulated weight-bearing positions were performed monthly for all dogs. Acetabular angle, dorsal acetabular rim angle (DARA), and femoral head diameter (FHd) were analyzed as skeletal variables; the lateral center edge angle (LCEA), dorsolateral subluxation (DLS) score, and center distance (CD) index were analyzed as joint laxity variables. At 12 months, all dogs underwent the Ortolani test to as-sess hip joint laxity. RESULTS: Hip joint laxity was detected in 5 dogs (10 joints) at 12 months of age; from 2 months, the acetabular angle and FHd increased and DARA decreased significantly until 5 months and the LCEA and DLS score increased significantly until 6 months. In nonlax hip joints in both positions, the CD index decreased significantly until 4 months of age and be-came stable thereafter. In lax hip joints, the CD index increased from 4 through 12 months; between 8 and 12 months, these changes were significantly greater in the weight-bearing position than in the standing position. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that CT-detected abnormalities in the DARA and CD index during body weight loading might be useful indicators of hip dysplasia in 2- to 6-month-old dogs.     

MRI features of cervical articular process degenerative joint disease in Great Dane dogs with cervical spondylomyelopathy

Cervical spondylomyelopathy or Wobbler syndrome commonly affects the cervical vertebral column of Great Dane dogs. Degenerative changes affecting the articular process joints are a frequent finding in these patients; however, the correlation between these changes and other features of cervical spondylomyelopathy are uncertain. We described and graded the degenerative changes evident in the cervical articular process joints from 13 Great Danes dogs with cervical spondylomyelopathy using MR imaging, and evaluated the relationship between individual features of cervical articular process joint degeneration and the presence of spinal cord compression, vertebral foraminal stenosis, intramedullary spinal cord changes, and intervertebral disc degenerative changes. Degenerative changes affecting the articular process joints were common, with only 13 of 94 (14%) having no degenerative changes. The most severe changes were evident between C4-C5 and C7-T1 intervertebral spaces. Reduction or loss of the hyperintense synovial fluid signal on T2-weighted MR images was the most frequent feature associated with articular process joint degenerative changes. Degenerative changes of the articular process joints affecting the synovial fluid or articular surface, or causing lateral hypertrophic tissue, were positively correlated with lateral spinal cord compression and vertebral foraminal stenosis. Dorsal hypertrophic tissue was positively correlated with dorsal spinal cord compression. Disc-associated spinal cord compression was recognized less frequently.     

Magnetic resonance arthrography of the cubital joint in dogs affected with fragmented medial coronoid processes

OBJECTIVE: To evaluate efficacy of intra-articular injection of gadolinium tetra- azacyclododecane tetraacetic acid (gadolinium-DOTA) for delineating fragmented medial coronoid processes (FMCP) and lesions on the medial aspect of the humeral condyle (MAHC). SAMPLE POPULATION: 14 cubital joints in 9 dogs. PROCEDURE: Magnetic resonance imaging (MRI) was performed with and without intra-articular injection of a solution of 2 mmol of gadolinium-DOTA/L. Arthrographic images obtained after injection of contrast medium were compared with those obtained without contrast medium. Evidence of contrast medium around or in the medial coronoid process and infiltration of contrast medium in subchondral bone lesions was recorded. Twenty-four hours after imaging, arthroscopy was performed, and lesions detected were correlated with results of MRI. RESULTS: An abnormal coronoid process was diagnosed in 13 of 14 joints. A fragmented process (free) was seen in 7 of 14 joints; nondisplaced mineralized medial (in situ) coronoid processes were evident in 4 joints; and nondisplaced unmineralized medial coronoid processes were evident in 2 joints. Lesions on the MAHC were diagnosed in 4 of 12 joints. In 5 joints, a hyperintense signal resulted from contrast medium that infiltrated between the fragmented process and ulna. In 2 joints, contrast medium did not infiltrate completely around the process and was stopped by an isointense structure (ie, abnormal cartilage). Subchondral bone lesions were enhanced by use of contrast medium. CONCLUSION AND CLINICAL RELEVANCE: Use of arthrography enabled us to identify FMCP easily, but did not provide important additional information about changes on the medial coronoid process, compared with MRI performed without contrast medium.     

Hind limb kinematics during therapeutic exercises in dogs with osteoarthritis of the hip joints

Objective-To assess joint kinematics in dogs with osteoarthritis of the hip joints during walking up an incline or down a decline and over low obstacles and to compare findings with data for nonlame dogs. Animals-10 dogs with osteoarthritis of the hip joints (mean ± SD age, 6.95 ± 3.17 years; mean body weight, 34.33 ± 13.58 kg) and 8 nonlame dogs (3.4 ± 2.0 years; 23.6 ± 4.6 kg). Procedures-Reflective markers located on the limbs and high-speed cameras were used to record joint kinematics during walking up an incline or down a decline and over low obstacles. Maximal flexion, extension, and range of motion of the hip joints were calculated. Results-Osteoarthritis of the hip joints reduced extension of both hip joints and flexion of the contralateral hind limb, compared with flexion of the lame hind limb, during walking down a decline. Walking up an incline resulted in decreased extension of the stifle joint in both hind limbs of osteoarthritic dogs; extension was significantly decreased for the lame hind limb. During walking over low obstacles, maximal flexion of the stifle joint was increased significantly for the contralateral hind limb. Maximal flexion was increased in both tarsal joints. Conclusions and Clinical Relevance-Osteoarthritis of the hip joints led to complex changes in the gait of dogs, which involved more joints than the affected hip joint alone. Each exercise had specific effects on joint kinematics that must be considered when planning a rehabilitation program.     

Detection of feline calicivirus antigens in the joints of infected cats

Twelve specific pathogen free cats were used to investigate the role of calicivirus in causing lameness. These were divided into two groups each of six cats; one group of cats had previously been vaccinated, the other had not. Three cats in each group were given live vaccine virus (F9 related) by the subcutaneous route and two in each group were challenged intranasally with field virus (A4), either four or seven days before euthanasia. The other two cats were controls. Virus was isolated from the oropharynx of five cats and the conjunctiva of a single cat. Four of these cats had been given the field virus and two the vaccine strain; the latter two cats had been previously immunised and had high circulating neutralising antibodies to calicivirus. No virus was isolated from the joints of any cat but immunofluorescence examination revealed viral antigens within the synovial macrophages of 14 joints from five cats, three having been given the field virus and two the vaccine virus seven days before euthanasia. Immunofluorescence also demonstrated the presence of immunoglobulin and complement within synovial macrophages suggesting that the virus was in the form of an immune complex. No lameness was reported in any cat and the synovial histological changes were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)     

MAGNETIC RESONANCE IMAGING SCORING OF AN EXPERIMENTAL MODEL OF POST‐TRAUMATIC OSTEOARTHRITIS IN THE EQUINE CARPUS

Magnetic resonance imaging (MRI) is the most sensitive imaging modality to detect the early changes of osteoarthritis. Currently, there is no quantifiable method to tract these pathological changes over time in the horse. The objective of this experimental study was to characterize the progression of MRI changes in an equine model of post‐traumatic osteoarthritis using a semiquantitative scoring system for whole‐organ evaluation of the middle carpal joint. On day 0, an osteochondral fragment was created in one middle carpal joint (OCI) and the contralateral joint (CON) was sham‐operated in 10 horses. On day 14, study horses resumed exercise on a high‐speed treadmill until the completion of the study (day 98). High‐field MRI examinations were performed on days 0 (preosteochondral fragmentation), 14, and 98 and scored by three blinded observers using consensus agreement. Images were scored based on 15 independent articular features, and scores were compared between and within‐groups. On days 14 and 98, OCI joints had significantly (P ≤ 0.05) higher whole‐organ median scores (29.0 and 31.5, respectively), compared to CON joints (21.5 and 20.0, respectively). On day 14, OCI joints showed significant increases in high‐signal bone lesion scores, and osteochondral fragment number and size. On day 98, high‐signal bone lesion, low‐signal bone lesion, osteophyte formation, cartilage signal abnormality, subchondral bone irregularity, joint effusion, and synovial thickening scores were significantly increased in OCI joints. Study results suggest that the MRI whole‐organ scoring system reported here may be used to identify onset and progression of pathological changes following osteochondral injury.     

Clinical and radiographic study of bone and joint lesions in 26 dogs with leishmaniasis

Twenty-six dogs with parasitologically confirmed leishmaniasis and abnormalities of gait were studied to determine the most common radiological patterns of bone and joint lesions. The clinical findings included either lameness, joint pain and crepitation, soft tissue swelling and/or muscle atrophy. Bone lesions were observed radiographically in 12 of the 26 dogs; the radius and ulna were affected in seven, the tibia in six and the femur in six. Joint lesions were observed radiographically in 15 of the 26 dogs; the carpus and stifle were affected in all 15, and the tarsus in nine. There was a tendency for the bones and joints to be affected bilaterally. The radiographic patterns observed were different in the long bones and the joints. In the long bones, the most common pattern was periosteal and intramedullary proliferation, involving the diaphyses and related to the nutrient foramen; in the joints, two patterns, either non-erosive or erosive polyarthritis with soft-tissue swelling, were observed. The changes observed in the synovial fluid were associated in most cases with osteolytic lesions. However, Leishmania organisms were identified in the synovial fluid from joints without bony radiographic changes.