Comparison of radiography and ultrasonography to detect osteochondrosis lesions in the tarsocrural joint: A prospective study

Reasons for performing study: Lesions located on the medial malleolus of the tarsocrural joint can be difficult to image radiographically. Ultrasonography allows evaluation of articular cartilage and subchondral bone. Objectives: To compare dorso30° lateral‐plantaromedial‐oblique (DL‐PlMO) and dorso45° views to detect lesions on the medial malleolus, to validate the use of ultrasonography to show lesions in the tarsocrural joint and to compare its sensitivity to radiography. Methods: Tarsocrural joints (n = 111) with osteochondrosis were evaluated ultrasonographically and radiographically prior to arthroscopic lesion debridement. A complete radiographic examination was made and the best view to detect each lesion recorded. Longitudinal and transverse ultrasonography of the dorsal aspect of the joint was performed and the best scan plane to image each lesion recorded. Results: There were 94 joints with lesions on the distal intermediate ridge of tibia, 24 with lesions on the medial malleolus, and 4 with lesions on the lateral trochlear ridge. The sensitivity of radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 71 and 96%, respectively. Eighty‐two percent of lesions on the medial malleolus were better imaged on dorso30° view. The sensitivity of ultrasonography to detect lesions on the medial malleolus and distal intermediate ridge of tibia was 83 and 98%, respectively. Ultrasonography was significantly more sensitive than radiography to detect lesions on the medial malleolus and distal intermediate ridge of tibia. Conclusion: Dorso30° lateral‐plantaromedial‐oblique view was the best to image lesions on the medial malleolus. Ultrasonography was a valuable diagnostic tool to diagnose lesions in the tarsocrural joint and was more sensitive than radiography for lesions located on the medial malleolus and distal intermediate ridge of tibia. Clinical relevance: Radiographic examination should include a dorso30° view for detection of lesions on the medial malleolus and ultrasonography should be considered to diagnose osteochondrosis in the tarsocrural joints.     

Osteochondrosis lesions of the lateral trochlear ridge of the distal femur in four ponies

Lesions of the lateral trochlear ridge (LTR) of the distal femur were investigated in four pony or pony cross horses. The animals were all geldings and were six to 15 months of age. Lesions were bilateral in three ponies and unilateral in one. Femoropatellar joint effusion and lameness were present in two ponies; clinical signs were absent in the others. The proximal LTR was affected in all four animals. The radiographic appearance of the lesions was a subchondral defect containing mineralised bodies. Arthroscopic and postmortem examination findings included an osteochondral flap, a fissured or irregular articular surface and a smooth surface overlying focally thickened cartilage that extended into subchondral bone. Thickened articular cartilage was a histological feature of all the lesions. Among the other histological features, the most common were chondronecrosis, chondrocyte clusters, phenotypically abnormal chondrocytes, horizontal fissures at the osteochondral junction and retained blood vessels. The signalment of the four ponies, their clinical signs and the pathological features of their lesions were consistent with osteochondrosis of the LTR in horses. The use of multiple criteria was considered to be important in making a specific diagnosis.     

Use of a flexed dorsoplantar radiographic view of the talocrural joint to evaluate lameness in two dogs.

A flexed dorsoplantar radiographic view of the talocrural joint was a useful additional view to diagnose abnormalities of the lateral trochlear ridge of the talus of 2 dogs. This view outlined the subchondral bone of both trochlear ridges of the talus and the apposing cochlea tibiae of the distal portion of the tibia. The tarsus was flexed at the level of the talocrural joint, and an x-ray beam was centered on the joint. With this additional view, fractures of the lateral trochlear ridge were readily diagnosed. This view would help to demonstrate osteochondral lesions of the lateral trochlear ridge.     

DIAGNOSTIC SENSITIVITY AND INTEROBSERVER AGREEMENT OF RADIOGRAPHY AND ULTRASONOGRAPHY FOR DETECTING TROCHLEAR RIDGE OSTEOCHONDROSIS LESIONS IN THE EQUINE STIFLE

Osteochondrosis lesions commonly occur on the femoral trochlear ridges in horses and radiography and ultrasonography are routinely used to diagnose these lesions. However, poor correlation has been found between radiographic and arthroscopic findings of affected trochlear ridges. Interobserver agreement for ultrasonographic diagnoses and correlation between ultrasonographic and arthroscopic findings have not been previously described. Objectives of this study were to describe diagnostic sensitivity and interobserver agreement of radiography and ultrasonography for detecting and grading osteochondrosis lesions of the equine trochlear ridges, using arthroscopy as the reference standard. Twenty‐two horses were sampled. Two observers independently recorded radiographic and ultrasonographic findings without knowledge of arthroscopic findings. Imaging findings were compared between observers and with arthroscopic findings. Agreement between observers was moderate to excellent (κ 0.48–0.86) for detecting lesions using radiography and good to excellent (κ 0.74–0.87) for grading lesions using radiography. Agreement between observers was good to excellent (κ 0.78–0.94) for detecting lesions using ultrasonography and very good to excellent (κ 0.86–0.93) for grading lesions using ultrasonography. Diagnostic sensitivity was 84–88% for radiography and 100% for ultrasonography. Diagnostic specificity was 89–100% for radiography and 60–82% for ultrasonography. Agreement between radiography and arthroscopy was good (κ 0.64–0.78). Agreement between ultrasonography and arthroscopy was very good to excellent (κ 0.81–0.87). Findings from this study support ultrasound as a preferred method for predicting presence and severity of osteochondrosis lesions involving the femoral trochlear ridges in horses.     

Multiple Osteochondral Autografts for Treatment of a Medial Trochlear Ridge Subchondral Cystic Lesion in the Equine Tarsus

Objective— To adapt the multiple osteochondral autograft technique for treatment of a subchondral cystic lesion (SCL) of the proximal medial trochlear ridge (MTR) of the equine talus and assess long term outcome.
Study Design— Case report.
Animals— Quarter horse stallion with SCL of the proximal MTR of the talus.
Methods— Osteochondral autograft techniques used in dogs and humans were adapted and optimized in equine cadavers. A horse with a SCL of the MTR of the talus was treated by osteochondral autografting. Three osteochondral autografts were harvested from the distal lateral trochlear ridge of the talus in the affected tarsus. No curettage or debridement of the osteochondral lesion was performed. Three recipient beds were predrilled and osteochondral autografts were press-fit into the proximal MTR of the talus. Outcome was assessed by radiography, telephone interview of the owner, and direct observation during training.
Results— Postoperative radiographs indicated excellent filling of the osteochondral defect and graft-articular surface congruency. No complications were encountered after surgery. At 10 months after surgery, the horse successfully re-entered reining training, and continued to be sound and performing athletically 2 years after surgery.
Conclusion— Osteochondral autografting deserves consideration and further evaluation as a primary treatment option for SCL of the proximal MTR of the talus in horses.
Clinical Relevance— Based on the outcome of this case, osteochondral autografting appears to be a safe, valuable and realistic option for treating SCL of the proximal MTR of the talus in equine athletes.     

Osteochondritis dessicans and subchondral cystic lesions in draft horses: a retrospective study.

The clinical features, radiographic findings, treatment, and outcome in 51 draft horses with osteochondritis dessicans (OCD) or subchondral cystic lesions (SC) are reported. Clydesdale and Percheron were the most commonly affected breeds, and affected animals represented only 5% of the hospital population of draft horses. Horses were most frequently affected in the tibiotarsal joints and 73% (24 of 33 cases) of the horses with tibiotarsal effusion were affected bilaterally. Osteochondritis dessicans of the distal intermediate ridge was the most common lesion found in the tibiotarsal joint. The stifle was also frequently affected; 87% (13 of 15 cases) of horses with femoropatellar OCD only were lame, and lesions were most commonly located on the lateral trochlear ridge. Sixteen cases were managed conservatively, 30 received surgery, and 5 were euthanized. Lameness, effusion, or both clinical signs resolved in more than 50% of surgically treated cases, but clinical signs improved in 30% of conservatively-managed cases.     

COMPARISONS AMONG RADIOGRAPHY,ULTRASONOGRAPHY AND COMPUTED TOMOGRAPHY FOR EX VIVO CHARACTERIZATION OF STIFLE OSTEOARTHRITIS IN THE HORSE

A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US evaluations were performed on 23 equine cadaver stifles and compared with ME. Significant associations were found between osteophyte global scores for all imaging modalities (CT, P ? 0.0001; XR, P = 0.005; US, P = 0.04) vs. ME osteophyte global scores. Osteophytes were detected most frequently in the medial femorotibial (MFT) joint. A specific pattern of osteophytes was observed, with a long ridge of new bone at the insertion of the MFT joint capsule cranially on the medial femoral condyle. A novel caudo‐10°proximo‐5°lateral‐cranio‐disto‐medial oblique radiographic projection was helpful for detection of intercondylar osteophytes. Multiplanar CT reformatted images were helpful for characterizing all osteophytes. Osteophyte grades at most sites did not differ among modalities. Low sensitivity/specificity for subchondral bone sclerosis and flattening of femoral condyles suggested that these signs may not be reliable radiographic and CT indicators of equine stifle OA. Equine stifle OA was associated with a decrease in BMD and specific sites of focal subchondral bone resorption/cyst formation were found in some specimens.     

Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint

REASONS FOR PERFORMING STUDY: To improve osteochondral graft reconstruction of subchondral cystic lesions in the medial and lateral femoral condyles by matching the material properties of donor and recipient sites. OBJECTIVES: To measure biomechanical and biochemical parameters that influence the function and healing of osteochondral grafts used to reconstruct subchondral cystic lesions. HYPOTHESIS: Suitable donor sites are available within the stifle joint for reconstructing the femoral condyles, despite considerable regional property variation. METHODS: Fifty-six osteochondral cores were harvested from 6 distal femurs for initial studies that determined subchondral bone modulus of elasticity and ultimate stress. In a second study, 28 osteochondral cores were harvested from 6 distal femurs to measure cartilage aggregate modulus, thickness and sulphated glycosaminoglycan (sGAG) content. Using micro-CT imaging, subchondral bone mineral density and bone volume fraction were also measured. In both studies 2-dimensional contour plots using a bicubic interpolation method and normalised data were generated to allow visual comparison of joint surface characteristics. Statistical comparisons between donor and recipient site raw data were made using an ANOVA for repeated measures with a post hoc Tukey test. RESULTS: Material properties of cartilage and bone vary considerably over the surface of the stifle joint but the central region of the medial condyle, where subchondral cystic lesions freqdently occur, typically demonstrated bone strength and modulus values of the highest observed. Cartilage thickness and aggregate modulus were highest in the medial femoral condyle and axial aspect of the lateral condyle. CONCLUSIONS: Material properties of the grafts from the trochlear groove and axial aspect of the lateral trochlear ridge were the closest match for those found in the medial condyle, whereas properties of the lateral condyle were most similar to those found in the trochlear groove and axial aspect of the medial trochlear ridge.     

Osteochondrosis of the Lateral Trochlear Ridge of the Talus in Seven Rottweiler Dogs

Eleven lesions of osteochondrosis in the lateral trochlear ridge of the talus were diagnosed in seven young Rottweiler dogs. Diagnosis was based on clinical and radiographic evaluations. Defects in the lateral trochlear ridge and osteochondral fragments arising from the dorsal and proximal margins of the ridge were visible radiographically. The dorsal 45 degrees lateral-plantaromedial oblique (D45 degrees L-P1MO) projection was the most useful in identifying the lesions. Exploratory arthrotomies were performed in six affected tarsi. In three cases, histologic examination revealed mineralized osteochondral fragments consistent with a diagnosis of osteochondrosis.     

COMPARISON OF RADIOGRAPHIC SUBCHONDRAL BONE CHANGES WITH ARTHROSCOPIC FINDINGS IN THE EQUINE FEMOROPATELLAR AND FEMOROTIBIAL JOINTS: A RETROSPECTIVE STUDY OF 72 JOINTS (50 HORSES)

Radiographs of 72 femoropatellar and femorotibial joints from 50 horses were evaluated. Ninety four arthroscopically evaluated areas were graded according to a predetermined system. The radiographic grade was then compared to arthroscopic findings in the same location. Statistical analysis was performed to determine the association between the radiographic subchondral bone changes and arthroscopic findings. Radiographically normal areas in the femoropatellar joint were arthroscopically positive for cartilaginous changes in 40% of the femoropatellar joints. Areas of mild subchondral bone flattening (grade I) in the lateral trochlear ridge were arthroscopically positive for cartilage changes 78% of the time. Ninety six percent of moderate to severe subchondral bone changes (grades II-V) were arthroscopically positive for cartilage damage. This research demonstrates that (1) a significant number of radiographically normal joints will have cartilage changes, (2) areas of mild subchondral bone flattening have cartilage changes present in the majority of cases and (3) areas of moderate to severe subchondral bone changes have arthroscopically detectable cartilage changes present.     

Computed tomography assisted diagnosis and treatment of a comminuted fracture of the plantar aspect of the medial trochlear ridge and the proximal tubercle of the talus in a foal

Isolated fractures of the proximal tubercle of the talus and the medial trochlear ridge of the talus have been reported in the equine literature. A comminuted, intra-articular fracture of the plantar medial trochlear ridge and proximal tubercle of the talus has not been previously reported. The current case report describes this unique comminuted fracture in a 6-week-old Thoroughbred foal with acute onset lameness. The diagnosis was achieved by a combination of radiography, ultrasonography and computed tomography (CT) followed by CT arthrography. Surgical removal of the fracture fragments was recommended; the intra-articular fracture fragments were removed under arthroscopic visualisation of the plantar pouch of the tarsocrural joint; due to ligamentous attachments and partial extra-articular nature, the fracture fragment of the proximal tubercle of the talus was removed via an arthrotomy extension of the medial arthroscopy portal. On follow-up examination 12 months post-operatively, the yearling showed no clinical evidence of lameness or radiographic evidence of secondary degenerative joint disease.     

Osteochondrosis and osteochondral fragments in Standardbred trotters: prevalence and relationships

Reasons for performing study: Developmental orthopaedic diseases (DOD) such as osteochondrosis (OC)/osteochondrosis dissecans (OCD), palmar/plantar osteochondral fragments (POF), ununited palmar/plantar eminences (UPE) and dorsoproximal first phalanx fragments are well recognised in the horse. Aetiopathogeneses are controversial and molecular genetic screening of DNA has recently been employed for their elucidation. Precise phenotypic definition and knowledge of breed‐specific prevalence and interrelations are essential for the interpretation of following genomic studies in Standardbred trotters. Objectives: To assess the prevalence, trend of development and interrelation of DOD in tarsocrural, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in Standardbred trotters. Methods: The tarsocrural and MCP/MTP joints of 464 Norwegian Standardbred yearlings were radiographed and the prevalence and interrelation of osteochondral lesions calculated. Results: Osteochondral lesions were diagnosed in 50.7% of the horses. The prevalence of tarsocrural OC/OCD at the distal intermediate ridge of the tibia (DIT) and the lateral trochlear ridge of the talus (LTT) was 19.3%. The prevalence of OC/OCD in MCP joints was 3.6%, whereas those of POF and UPE in MCP/MTP joints were 23.1 and 3.9%, respectively. Interrelation was evident for 1) most equivalent lesions in joint homologues, 2) OCD DIT and OCD LTT and 3) POF and UPE. Lesions in hock and fetlock joints were generally not significantly associated. Conclusions: The prevalence of tarsocrural OC/OCD in Norwegian Standardbreds is apparently increasing, whereas that of other articular DOD appears stable. Association analyses verify bilateralism for most equivalent lesions and suggest aetiological resemblance also between other lesions. The absence of a significant association between tarsocrural OCD and POF implies that the lesions must be considered statistically different disorders. Potential relevance: The prevalence results emphasise that DOD should be considered in Standardbred breeding regimens (e.g. by sire selection subsequent to progeny testing). Also, improved phenotypic definitions will help elucidate the true causal genes in following genomic studies.     

Unusual osteochondral lesions of the talus in a horse

A 2-year-old Thoroughbred gelding was evaluated for a grade 3 out of 5 unilateral hind limb lameness. Flexion of the right hock and stifle joints (spavin test) exacerbated the lameness. Response to intra-articular and perineural anaesthesia isolated the source of lameness to the tarsocrural area, despite an absence of tarsocrural joint effusion. Routine radiographic examination of the hock did not reveal any significant abnormalities. Skeletal nuclear scintigraphic evaluation revealed a focal region of increased bone activity in the proximal medial trochlear ridge of the talus. Flexed lateromedial radiographic views identified three discrete semicircular lytic lesions at the proximal articular margin of the medial trochlear ridge of the talus. Conservative management of the lesions was associated with a successful return to racing. The location and appearance of the osteochondral lesions of this report have not been previously reported and may be a manifestation of developmental orthopaedic disease and abnormal endochondral ossification. Nuclear scintigraphy and flexed lateromedial radiographic views facilitated identification of the lesions. This radiographic view is recommended when lameness is isolated to the tarsocrural joint and standard radio-graphic projections fail to identify a cause.     

Osteochondral Defects of the Lateral Trochlear Ridge of the Distal Femur of the Horse Clinical, Radiographic, and Pathological Examination and Results of Surgical Treatment

Osteochondral defects of the lateral trochlear ridge of the distal femur were identified in 15 joints of 10 horses. Lesions were bilateral in five horses and unilateral in five horses. Thirteen of these 15 defects were treated by curettage through a craniolateral femoropatellar arthrotomy. Subcutaneous seroma formation and partial skin dehiscence occurred in nine stifles. Lameness attributable to the stifle joint was no longer apparent at 6 and 12 months after surgery. The normal subchondral bony contour of the lateral trochlear ridge was altered in all joints after surgery. The subchondral bone was uniformly increased in density in all joints, and six lateral trochlear ridges had small focal radiolucent regions within the subchondral bone, which suggested that complete removal of the original lesion had not been achieved. Healing of the surgical site between 2 weeks and 14 months was evaluated in four joints. Granulation tissue from mesenchymal elements in subchondral marrow spaces gradually filled the defects with fibrocartilage.     

Diagnostic procedures and surgical treatment of craniodorsal coxofemoral luxation in calves

OBJECTIVE: To report use of ultrasonographic examination of the coxofemoral joint, a surgical technique for repair of craniodorsal coxofemoral dislocation, and outcome. STUDY DESIGN: Clinical case reports. ANIMALS: Calves (n=4) with coxofemoral luxation. METHODS: Craniodorsal coxofemoral luxation was diagnosed by physical examination, radiographic, and ultrasonographic findings. Open surgical reduction of the femoral head was performed using a modified caudal approach. RESULTS: Craniodorsal luxation of the femoral head and the presence of an intact femoral neck were confirmed by ultrasonography. All luxations were successfully reduced and reluxation did not occur. At follow-up, 1 heifer had calved and 1 was 5 months pregnant. One calf died of bronchopneumonia 6 days after surgery. One calf had severe coxofemoral degenerative joint disease diagnosed (ultrasonography, radiography, and arthrocentesis) 3 months after surgery and confirmed by necropsy. CONCLUSION: Ultrasonography proved to be a simple and effective non-invasive technique for diagnosis of coxofemoral luxation. Immediate surgical intervention in hip dislocation in calves is necessary to avoid unnecessary trauma to subchondral structures. In calves, open instead of closed surgical reduction appears preferable because it allows access to the acetabular cavity for removal of debris. CLINICAL RELEVANCE: Ultrasonography should be considered a supplementary but not an alternative to radiographic examination for diagnosis of coxofemoral luxation and for follow-up examinations after reduction.     

THREE-DIMENSIONAL ULTRASONOGRAPHIC IN VITRO IMAGING OF LESIONS OF THE MENISCUS AND FEMORAL TROCHLEA IN THE EQUINE STIFLE

The purpose of this in vitro study was to evaluate the value of three-dimensional (3D) ultrasonography for the diagnosis of equine meniscal and trochlear ridge lesions under in vitro conditions. Lesions were created in the isolated meniscus and femoral trochlea of 25 cadaver stifle joints. Cylindric, conic, and cuboid lesions were created on the trochlear ridge. Five different meniscal tear configurations were created. A total of 107 lesions of the trochlear ridge and 103 lesions of the meniscus were created. 3D ultrasonography was performed in a waterbath, using a 7.5 MHz 3D scanner. Trochlear ridge lesions were seen as either hypoechoic or anechoic breaks in continuity or as irregular notches. One-hundred and one out of the 107 trochlear lesions were visible using 2D ultrasonography whereas 104 out of the 107 lesions could be seen using the 3D Cine mode. Three lesions could not be detected by either technique. Eighty-five out of the 103 meniscal lesions were seen with 2D ultrasonography and 90 with 3D Cine mode. Radial tears and horizontal tears were the least commonly visualized 3D. The 3D Cine mode led to a small improvement in lesion detection. 3D ultrasound could be considered as an extension and refinement of the ultrasound techniques already in use and can increase the diagnostic capabilities. However, technical improvements have to be achieved before 3D ultrasound can be used in the daily practice for diagnosis of equine stifle joint disorders.     

Progression of Femoropatellar Osteochondrosis in Nine Young Horses Clinical, Radiographic and Arthroscopic Findings

The clinical and radiographic progression, and arthroscopic findings for nine young horses (<1 year of age) with femoropatellar osteochondrosis (OCD) are presented. Horses had a 2 to 12 week history of bilateral (8 horses) or unilateral (1 horse) hindlimb lameness. The most consistent clinical signs included femoropatellar joint distention and bilateral hindlimb lameness. At the onset of clinical signs, radiographic lesions were not present (4 horses) or subtle (5 horses), but were easily identified on radiographs taken 4 to 24 weeks later. Arthroscopic surgery was delayed until radiographic changes became obvious. Surgical findings in 20 femoropatellar joints were most commonly osteochondral "flaps" located on the proximal lateral trochlear ridge of the femur and were larger than had been indicated by the radiographs. Eight horses were being used for their intended purpose, which was racing (3 horses were racing and 3 were in race training), dressage (1 horse) or pleasure riding (1 horse). One horse required a second surgery when similar lesions developed in the opposite stifle, and was euthanatized 2 months later because of persistent lameness. Once clinical signs are observed, osteochondrosis lesions of the distal femur can progress in foals younger than 9 months of age and the full extent of the radiographic lesion may take several weeks to develop.     

Oral hyaluronan gel reduces post operative tarsocrural effusion in the yearling Thoroughbred

REASONS FOR PERFORMING STUDY: Hyaluronan (HA) has been used to treat joint disease via intra-articular, i.v. and oral administration. The efficacy of intra-articular and i.v. use has been evaluated but the oral route has yet to be examined. OBJECTIVES: To determine the effect of oral hyaluronan gel on joint effusion following arthroscopic surgery for osteochondritis dissecans (OCD) of the tarsocrural joint of yearling Thoroughbreds. METHODS: Forty-eight yearlings diagnosed with unilateral or bilateral osteochondritis dessicans (OCD) of the tarsus were arbitrarily chosen prior to arthroscopic surgery. The yearlings were included only if they had mild or no synovial effusion pre-surgery. Twenty-four of the yearlings (27 joints) were treated with 100 mg of HA orally for 30 days post operatively and 24 (30 joints) with a placebo orally for 30 days. At 30 days post operation, a blinded examiner scored the effusion of the dorsomedial tarsocrural joint individually using a scale of 0 to 5 (0 = no effusion, 1 = barely palpable effusion, 2 = palpable effusion [without plantar effusion], 3 = golf ball sized effusion with plantar effusion, 4 = tennis ball sized effusion with plantar effusion, 5 = > tennis ball sized effusion with plantar effusion). Half grades were allowed and OCD lesion sizes and locations were compared. RESULTS: A total of 57 joints were examined, of which 33 had OCD of the distal intermediate ridge of the tibia, 19 OCD of the distal lateral trochlear ridge of the talus and 5 OCD of the medial malleolus. The mean 30 day effusion score of the HA treated group (27 joints) was 0.67 while the mean of the 30 day placebo group (30 joints) was 2.05 (P < or = 0.0001). Similar results were noted when comparing treated vs. placebo for each lesion location as well as for lesion sizes. CONCLUSIONS AND POTENTIAL RELEVANCE: Oral preparations of hyaluronan are being used to treat joint disease in horse. Anecdotal reports supporting the efficacy of these preparations already exist. This study provides objective evidence that oral HA reduces joint effusion post operatively following the arthroscopic removal of an OCD lesion in the tarsocrural joint.     

Radiographic, computed tomographic and arthroscopic findings in 23 dogs with osteochondrosis of the tarsocrural joint

Twenty-three dogs with osteochondrosis of the tarsocrural joint were evaluated by radiography, computed tomography (CT) and arthroscopy. The radiographic examination included an extended and flexed mediolateral, a plantarodorsal, a flexed dorsoplantar skyline view, and a plantaromedial-dorsolateral and a plantarolateral-dorsomedial view (two oblique views). The CT examination was carried out in ventral recumbency and 1 mm slices were taken with a bone window setting; 31 lesions were identified in the 46 joints examined. The arthroscopic exploration used either a plantar or a dorsal puncture, depending on the site of the lesion. In six cases the lateral, and in 17 cases the medial trochlear ridge was involved. Although the survey radiographs were sufficient to make a diagnosis, the CT examination helped to determine the exact site, and the number and size of the fragments of bone. A four-stage classification system comparable to the one used in man was established. Arthroscopy provided information about synovial inflammation and damage to the joint cartilage, and made it possible to remove fragments of bone from one-third of the cases.