Geometry of the femoral condyles in dogs

The stifle joint is one of the most important joints in dogs from the orthopaedic point of view. The aim of this study was to document the morphometric values of femoral condyles, given the close relationship between the shape and function of an anatomic structure. The left femora of 16 mid-sized dogs were used, and diameter and nine radii as well as cranial and caudal bow lengths from each condyle were measured. The photographs were taken of the distal femora from both sides. All measurements were obtained from these images by using software. Additionally, the rotation angle was calculated from the intercondylar distance and the difference between lateral and medial bow lengths. In addition to the rotation angle, the difference of diameter and nine radii between the lateral and medial condyles was determined. All radii except getting at 90° were significantly different between the medial and lateral condyles. The greatest values were determined in the caudal part of the medial condyle. This results the smaller contact area and a greater pressure on the underlying surface, and therefore the meniscus and articular cartilage of the caudal part of the medial side suggests the possibility of a risk of injury as the stifle joint flexes. The mean rotational angle of the femur was also calculated to be 2.18° laterally and 1.02° medially in the caudal and cranial parts of condyles, respectively. The result of this study showed that the lateral and medial condyles had different shapes in canine femur.     

Morphometrical Study of Bony Elements of the Forelimb Fetlock Joints in Horses

There are many reports describing fractures in the bony elements of the equine fetlock joint and a few of these discuss possible relationships of these fractures to the mechanical loading of these bones. The likelihood of fracture must be related to the size and shape of bones involved, but information concerning the normal range in size and shape of these bones in horses is lacking. This study aimed to identify morphometrical variations of these bones within different groups of horses. Right and left metacarpal, proximal phalangeal and proximal sesamoid bones were collected from 10 Thoroughbreds (TB), five Standardbreds (SB) and eight Ponies (P) euthanized for non‐orthopaedic reasons. All bones were boiled, cleaned and dried. Dimensional parameters were measured using a custom‐built apparatus, calliper and plastic tape. The width and depth of the medial condyles of Mc3 were greater than the lateral condyles in all groups. The length to the lateral condyle was greater than the length to the medial condyle of Mc3, and the lengths of the lateral sides of the Mc3 and P1 bones were greater than the lengths of the medial sides in both forelimbs of all groups. The lateral sesamoids were similar to, or larger than, the medial sesamoids in all dimensions. There were some morphometrical variations in the bony elements of the equine fetlock joints in all groups.     

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.     

Evaluation of the Marsh Deer Stifle Joint by Imaging Studies and Gross Anatomy

This study aimed to evaluate the stifle joint of marsh deer using imaging studies and in comparison with gross anatomy. Ten hindlimbs from 5 marsh deer (Blastocerus dichotomus) were used. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in each stifle joint. Two hindlimbs were dissected to describe stifle gross anatomy. The other limbs were sectioned in sagittal, dorsal or transverse planes. In the craniocaudal radiographic view, the lateral femoral condyle was broader than the medial femoral condyle. The femoral trochlea was asymmetrical. Subsequent multiplanar reconstruction revealed in the cranial view that the external surface of the patella was roughened, the medial trochlea ridge was larger than the lateral one, and the extensor fossa at the lateral condyle was next to the lateral ridge. The popliteal fossa was better visualized via the lateral view. Sagittal MRI images identified lateral and medial menisci, caudolateral and craniomedial bundles of cranial cruciate ligament, caudal cruciate ligament, patellar ligament and common extensor tendon. In conclusion, the marsh deer stifle presents some anatomical characteristics of the ovine stifle joint.     

Mapping of Split-Line Pattern and Cartilage Thickness of Selected Donor and Recipient Sites for Autologous Osteochondral Transplantation in the Canine Stifle Joint

Objective— To characterize donor and recipient sites for autologous osteochondral transplantation in the canine stifle joint with respect to split-line pattern and cartilage thickness.
Study Design— In vitro study.
Sample Population— Stifle joints (n=30) of dogs >20 kg.
Methods— Collagen network orientation of the hyaline cartilage coverage of the distal femur was assessed using split-line technique (n=10). Cartilage thickness was measured radiographically on osteochondral plugs harvested at the abaxial and axial surfaces of the femoropatellar joint (n=15), the most proximal abaxial aspect of the medial condyle (CO; n=5) and at both femoral condyles (n=15).
Results— Cartilage within the femoropatellar joint and both femoral condyles had mostly transversely orientated pattern of split-lines. Abaxial to the femoropatellar joint split-lines were absent. All donor sites had significantly thinner cartilage than the medial condyle (CM). Only the distal trochlea had cartilage thickness comparable to the lateral condyle (CL). The thinnest cartilage was found abaxial to the femoropatellar joint followed by CO, which was ∼2–3 times thinner than the cartilage at both condyles.
Conclusions— None of the investigated donor sites provided transplants of comparable cartilage thickness to CM. Transplants from within the femoropatellar joint should be harvested in priority as they reach cartilage morphology comparable to CL.
Clinical Relevance— Adjusting for cartilage thickness and split-line pattern may improve long-term outcome after autologous osteochondral transplantation. But surface curvature and donor-site morbidity have to be considered as well when choosing the most suitable donor site.     

Difference in the length of the medial and lateral metacarpal and metatarsal condyles in calves and cows--a post-mortem study

Measurements were taken in the metacarpal and metatarsal bones in 42 calves and 10 dairy cows post-mortem to determine whether there are anatomical differences in bone length. Manual and digital measurements of various bone length parameters were taken. There was a significant difference in the mean length of the condyles of the metacarpal and the metatarsal bones in calves and cows, the lateral condyle being longer than the medial. In all but one metatarsal bone (98.8%), the lateral condyle was longer than the medial. In the metacarpal bones, the lateral condyle was longer in only 52.4% of the bones, in 21.2%, they had the same length and in 27.4% the medial condyle was longer. These intrinsic anatomical differences can help distinguish between the left and right metacarpal and metatarsal bones, for instance, in anatomical and archaeological studies. Knowledge of these differences might be useful for studies on digit function and on the possible predisposition of cattle to claw diseases in the lateral claws of the hind limbs.     

Evaluation of analytical grade of metrizamide for canine stifle arthrography

The use of analytical grade of metrizamide as contrast material in canine stifle arthrography was evaluated in 27 stifle joints. A concentration of 280 mg of I/100 ml was prepared, and the material was injected at a rate of 0.3 ml/cm thickness of the lateral to medial measurement. Acceptable arthrograms were produced in 22 (81.5%) cases. The mediolateral radiographic view was useful in demonstrating the cranial and caudal cruciate ligaments, the infrapatellar fat pad, and the tendon of the long digital extensor muscle. The caudocranial radiographic view was useful in demonstrating the medial and lateral menisci, the articular surfaces of the femoral condyles, and the outline of the joint capsule. Radiographs made within 15 minutes after injection of the contrast medium were acceptable, thus setting this period as the limit for obtaining useful arthrograms. The double contrast technique was found to be of little value.     

GROSS AND HISTOPATHOLOGIC CORRELATION OF LOW‐FIELD MAGNETIC RESONANCE IMAGING FINDINGS IN THE STIFLE OF ASYMPTOMATIC HORSES

With the recent introduction of a 0.25T rotating MRI system, clinical evaluation of the equine stifle joint is now possible in the average equine athlete. A recent publication described common abnormalities of horses with stifle lameness detected with a low‐field MRI system; however, postmortem corroboration of the lesions detected was not possible. Therefore, our objective was to compare postmortem findings with low‐field MRI findings in equine cadaver stifle joints. Ten fresh cadaver stifle joints from horses without clinical signs of stifle disease were evaluated using low‐field MRI, gross dissection, and histopathology. In eight stifles, either the lateral or medial cranial meniscotibial ligament had an irregular shape, fiber separation, or moderate abnormal signal intensity (SI) on all sequences. In five stifles, the medial femoral condyle had articular cartilage fibrillation with or without an osteochondral defect over the weight bearing surface of the medial femoral condyle. All stifles had abnormal SI on all sequences within the patellar ligaments that corresponded with adipose tissue infiltrating between the collagen bundles. Other abnormalities identified included articular cartilage fibrillation of the tibial condyles in three stifles, and articular cartilage fibrillation with chondral defects in the patella in three stifles. All abnormalities detected with low‐field MRI were corroborated by gross dissection. Findings from the current study supported the use of low‐field MRI for detection of stifle joint lesions in horses and demonstrated that some stifle joint pathologies may be subclinical in horses.     

ULTRASONOGRAPHIC ANATOMY OF THE NORMAL CANINE STIFLE

Ultrasonographic examination of the normal canine stifle joint was performed to characterize its normal anatomy. Stifles of four normal adult dogs were imaged in sagittal and transverse planes and each anatomic structure visualized was recorded. Normal anatomic structures consistently seen included the patellar tendon, medial and lateral menisci, the cranial cruciate ligament and femoral condyle cartilage. The caudal cruciate ligament was visualized in two dogs. Collateral ligaments and meniscal ligaments were not visualized. The dogs were then euthanized and each stifle was isolated. Following removal of superficial muscles and skin, each stifle was imaged in a water bath to definitively identify the structures that had previously been visualized on the live dogs. The ultrasonographic appearance of the isolated stifle specimens was similar to that found in live dogs. The results of this study indicate that ultrasound can be used to image the normal anatomy of the canine stifle. The echogenicity of the patellar ligament, cruciate ligaments, menisci and articular cartilage was similar to that previously reported in equine stifles and human knees.     

Meniscal damage diagnosed by ultrasonography in horses: A retrospective study of 74 femorotibial joint ultrasonographic examinations (2000–2005)

This retrospective study reports diagnostic findings in 74 horses with ultrasonographic diagnosis of femorotibial joint damage; it describes the ultrasonographic features of meniscal tears and determines the prevalence of medial or lateral meniscal involvement and of associated synovial effusions. Horses were classified into four groups: with medial meniscal damage, with lateral meniscal damage, with lesions in both menisci, and with no ultrasonographic evidence of meniscal damage. After ultrasonographic appearance, meniscal lesions were described as central degeneration, horizontal tear, partial oblique tear of the distal angle, combined horizontal and oblique tears, or complex tear. Meniscal protrusion or other associated ultrasonographic or radiographic abnormalities were recorded. Of the 74 horses, 54 (73%) had medial meniscal damage, 5 (6.75%) had lateral meniscal damage, 5 (6.75%) had lesions in both menisci, and 10 (13.5%) had no meniscal lesion. Meniscal protrusion occurred in 20 cases (27%). Horizontal tears were the most frequent type of meniscal lesion (26 horses). Complex lesions were found in 6 lateral menisci and 14 medial menisci. Lesions of the cranial meniscal ligaments were seen in 10 horses. Synovial effusion of one or several joint compartments was found in 51 cases (68.9%).This study demonstrates the high prevalence of meniscal tears and synovitis in horses with ultrasonographic evidence of femorotibial derangement. Based on this series of clinical cases, horizontal tears of the medial meniscus appear to be the most frequent soft tissue injury of the equine stifle.     

Age‐related morphometric changes of the tidemark in the ovine stifle

Though the ovine stifle is commonly used to study osteoarthritis, there is limited information about the age‐related morphometric changes of the tidemark. The objective of this study was to document the number of tidemarks in the stifle of research sheep without clinical signs of osteoarthritis and of various ages (n = 80). Articular cartilage of the medial and lateral tibial condyles and of the medial and lateral femoral condyles was assessed by histology: (a) to count the number of tidemark; and (b) to assess the OARSI (Osteoarthritis Research Society International) score for structural changes of cartilage. The number of tidemarks varied between anatomical regions, respectively, from 4.2 in the medial femoral condyle to 5.0 in the lateral tibial condyle. The axial part showed a significant higher number of tidemarks than the abaxial part, for all regions except the medial tibial condyle. Whilst the tidemark count strongly correlated with age (Spearman's correlation coefficient = 0.70; 95% confidence interval (95% CI): 0.67–0.73; p < 0.0001), the OARSI score was weakly correlated with age in our cohort of sheep (Spearman's correlation coefficient = 0.25; 95% CI: 0.19–0.30; p < 0.0001). Interestingly, no tidemark was seen in the three animals aged 6 months. Our data indicate that the number of tidemarks increases with age and vary with anatomical region. The regional variation also revealed a higher number of tidemarks in the tibia than in the femur. This could be attributed to the local variation in cartilage response to strain and to the difference in chondrocyte biology and density.     

Osteology and radiology of the Maned Wolf (Chrysocyon brachyurus) pelvic limb

This study describes the osteology and radiology of the pelvic limb in maned wolves. Ten (five live and five dead) maned wolves (Chrysocyon brachyurus), five males and five females, aged from 2 to 7 years old were used. Digital radiographs were taken and recorded for both pelvic limbs in all animals. Osteology was correlated with the radiographic images. The pelvis had a rectangular shape, and the obturator foramen (foramen obturatum) was oval. The femoral neck (collum femoris) was short and thick. The greater trochanter (trochanter major) extended proximally to near the dorsum of the femoral head (caput ossis femoris). The lateral femoral condyle (condylus lateralis) was larger than the medial condyle (condylus medialis), and the intercondylar fossa (fossa intercondylaris) had a slightly oblique orientation. The proximal tibia displayed medial and lateral condyles with the medial larger. The femur was slightly shorter than the tibia. Seven tarsal bones (ossa tarsi) were present, four long metatarsal bones (ossa metatarsalia II ‐ V) and a short first metatarsal bone (os metatarsal I).     

Incomplete Ossification of the Humeral Condyle in Spaniels

An evaluation of 157 dogs with humeral fractures was performed. Cocker spaniels were more likely to have humeral condylar fractures (HCFs) than other breeds ( P < .0001). Male cocker spaniels were at increased risk ( P < .001). Cocker spaniels had more bilateral HCFs than other breeds of dogs ( P < .001). Eighteen dogs (17 purebred spaniels and 1 crossbred spaniel) with HCFs of unknown cause or occurring with normal activity were further studied, using radiography of their humeral condyle bilaterally (n = 18), computed tomography (n = 3), biopsy (n = 2), bone scintigraphy (n = 2), and genetic evaluation (n = 8). Fourteen of these 18 dogs had a nonfractured contralateral condyle. Twelve (86%) of the 14 nonfractured humeral condyles had a radiolucent line within the center of the condyle, 13 (93%) had radiographic signs of degenerative joint disease and an abnormal medial coronoid process, and six (43%) had periosteal proliferation involving the lateral epicondyle. Examination of biopsy samples from the fracture sites of two cocker spaniels showed fibrous tissue present at the fracture surfaces. The results of this study suggest an association between incomplete ossification of the humeral condyle in cocker spaniels and Brittany spaniels and a high prevalence of HCFs. Eight affected cocker spaniels with available pedigree information were found to be genetically related, suggesting that incomplete ossification of the humeral condyle may be a genetic disease with a recessive mode of inheritance.     

Osteochondritis dissecans of the canine stifle joint

In fourteen dogs with osteochondritis dissecans of the stifle joint the lesion was found in the articular cartilage of the medial condyle of the femur in six and the lateral condyle in eight. Both stifle joints were affected in eight dogs and in two of these, both Wolfhounds, the shoulder joints were also affected. Ten dogs were treated surgically and three by conservative means. The results of treatment are discussed.     

Surgical correction of congenital medial patellar luxation in a llama

Unilateral congenital medial patellar luxation in a young llama was corrected by medial joint capsule release, tibial crest transposition, trochleoplasty, and lateral joint capsule imbrication. The techniques used were the same as described in the dog. One year after surgery, the llama was not lame, but had a valgus deformity originating at the stifle, most likely caused by lateral femoral condyle hypoplasia.     

Magnetic Resonance Imaging of the Dorsal Proximal Synovial Plica of the Equine Metacarpo‐/Metatarsophalangeal Joint

A synovial plica is present at the dorsoproximal aspect of the fetlock joint. The objective of this study was to describe the location of the synovial plica during induced hyperextension using Magnetic Resonance Imaging. For this study 20 cadaver limbs from five Warmblood horses were used. Measurements were made of the dorsal; palmar/plantar length and the thickness of the plica with the joint in a normal position. During induced hyperextension of the joint, the position of the plica was described; the dorsal angle of extension and angle of contact between the proximal phalanx (P1) and the condyle were measured. The dorsal length differed between front/hind limbs and between the medial/lateral aspect of the joint. The angle of contact between P1 and condyle differed between front/hind limbs; between the lateral and medial aspect of the joint and between different positions of the plica. Four different positions of the plica were observed: shortened with the tip curved towards palmar/plantar; projecting distally; projecting towards dorsal and projecting distally with the tip interposed between P1 and the condyle. During induced hyperextension, a close relation is present between the synovial plica, P1 and the condyle with a variable position of the plica; which is suggestive for a contact interface between P1 and the metacarpal/metatarsal bone. However the plica does not seem to act consistently as a cushioning surface.     

Morphology and water and lipid contents of stifle menisci of growing swine.

Morphology and distribution of water and lipid were examined in menisci of growing swine. The broadness of menisci and the size of protruded tissue in the inner anterior portion of menisci varied among animals. Small tears of tissues were frequently observed. Both the thickness and tissue weight were greater in the lateral than in the medial meniscus. Water content and intensity of glycosaminoglycan staining with safranin-O were found to be greatest in the inner one-third of the meniscus, and greater in the middle than in the outer one-third of the meniscus. Lipid content was greater in the outer one-third than in the inner two-thirds of the meniscus.     

ULTRASONOGRAPHY OF THE EQUINE STIFLE

Ten stifles from 5 clinically sound adult horses were scanned by high-resolution ultrasound. Normal anatomic structures seen consistently included the subcutaneous tissue, the medial, middle and lateral patellar ligaments, the medial and lateral collateral ligaments, the femoral trochlear ridges, and menisci. Cruciate ligaments could not be visualized in the standing horse. Four stifle specimens obtained from 2 of these normal horses at necropsy were scanned in a water bath to create optimal technical conditions. The sonographic appearance of stifle specimens was similar to that found in live horses. Results from ultrasonographic examination of 3 horses with stifle abnormalities were described to illustrate some applications of ultrasonography in the evaluation of the equine stifle. In these horses, ultrasound was a valuable diagnostic tool to study joint effusion, synovial thickening, articular cartilaginous and subchondral defects, and soft tissue/bony injuries.     

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.