Developmental conditions Flashcards
What is Osteochondrosis and where does it commonly occur?
Dysfunction of the endochondral ossification and occurs in both articular epiphyseal cartilage complex and the growth plate. Articular cartilage becomes thickened because it does not mineralise.
Occurs in the shoulder (humeral head), Elbow (humeral condyle), stifle (femoral condyle), tarsus (talus). Can also occur in the physeal area, retained cartilaginous core, ununited anconeal process, ununited medial epicondyle of the humerus.
Characteristics and radiological changes of Shoulder osteochondrosis.
Humeral head. Males, 4-8mths, large giant breeds. 75% of OC cases. Varying lameness severity. Shortened forelimb stride. Pain on extension and flexion. Often bilateral.
Useful view: ML
Radiographic findings: Defect, flattening or irregularity of the caudal humeral head. Sclerosis of the subchondral bone. Mineralised flap present next to defect or mineralised joint mouse in the caudal joint pouch.
Characteristics and radiological changes of Elbow osteochondrosis.
Typically in males, 5-10mths, large breeds (often retrievers)
Seconds most common OC lesion, weight-bearing lameness exacerbated with exercise. Pain on hyperextension or flexion of the elbow. Often bilateral.
Useful views: CrCd and CrMd-CdLO
Subchondral defect on the articular surface of the medial humeral condyle. Subchondral sclerosis. Rarely has a mineralised flap or joint mouse. Don’t confuse the sesamoid on the lateral aspect with a joint mouse.
CAUSES ELBOW DYSPLASIA
Characteristics and radiological changes of Stifle osteochondrosis.
More commonly in males, 5-7 months, large breeds, especially Great Danes, Labradors, Golden retrievers, Newfoundland, and German shepherd.
Least common of the OC lesions. Insidious hind limb lameness exacerbated by exercise. Stifle joint pain, swelling, and reduced range of motion. Often bilateral.
Useful view: CrCd, ML
Medial aspect of the lateral femoral condyle is affected, sometimes both condyles affected. Radiolucent defect in the distal articular surface of the condyle, irregular margins. Subchondral sclerosis, intrascapular swelling commonly seen, may see mineralised flap/joint mouse.
Characteristics and radiological changes of Tarsus osteochondrosis.
Males and females equally affected, 6-12mths, large breed dogs, especially rottweilers and Labrador retrievers (over 70% of reported cases).
Third most common OC lesion. Progressive lameness of several months duration. Often hold affected leg in hyperextended position. Tarsal joint pain with flexion and extension, joint swelling. Bilateral in 40% of reported cases.
Flattened or misshapen Medial trochlear ridge (most commonly affected), lateral trochlear ridge may also be affected.
Useful view: DPl, extreme flexed LM.
Plantar aspect of joint appears widened and irregular, on the lateral view. Subchondral sclerosis, may see mineralised flap/joint mouse. Intracapsular swelling.
Elbow dysplasia causes and grading
Is a general terms used to identify an inherited polygenic disease in the elbow of dogs.
Manifestations:
- Fragmented medial coronoid process
- Ununited anconeal process
- Osteochondrosis of the medial humeral condyle
- Elbow incongruity
Grading
I: Minimal bone change along the anconeal process. Of the ulna (less than 2mm)
II: Additional bone proliferation along anconeal process (2-5mm) and subchondral bone changes (trochlear notch sclerosis).
III: Well developed degenerative joint disease with bone proliferation along anconeal process being greater than 5mm.
Fragmental medial coronoid process
Males, signs apparent from 4-7mths, radiographic changes 7-8mths. Medium to large breed dogs.
Change in gait characterised by inward rotation of the elbow, outward rotation of the paw, stiffness in the front legs. Decreased ROM. Often bilateral.
Rare to visualise the actual fragment, abnormally contoured or poorly defined medial coronoid process lateral view, blunted or rounded medial coronoid process on the CrCd view.
Sclerosis of the trochlear notch of the elbow, may cause kissing lesion on medial humeral condyle.
Ununited anconeal process
Males, 5-12mths, clinical signs don’t develop until later (7-8mth)
Large breed dogs. Normal alconeal process fuses to the olecranon by 20weeks, failure of fusion past 5 months is diagnositic.
Radiolucent line separating the anconeal process from the olecranon process, may be displaced. The radiolucent line is generally irregular and variable width. Fragments are often sclerotic. An extreme flexed lateral view will displace the physis of the medial humeral epicondyle.
Joint incongruity
Accurate assessment relies on optimum positioning.
Humero-ulnar joint space has radiographic assymetrical widening of the cranial or cordal part of the joint space.
Radioulnar joint typically results in a step defect between the radial head and the lateral coronoid process of the ulna.
Hip Dysplasia
No sex predilection, severe cases will often have signs by 5-12mths of age, mild cases wont be present until old age.
Large breed dogs more commonly affected as well as purebred and domestic cats. Joint laxity that leads to inappropriate development of the coxofemeral joint and subsequent development of secondary OA.
Abnormal gait, pain, reluctance to rise, climb stairs and jump.
Abnormal radiographic findings:
Shallow, flattened acetabular rim with flaring at the cranial margin, flattening of the femoral head, sublaxation or luxation of the femoral head (less than 2/3 coverage), lack of congruency of the joint (wedge shaped). Subchondral bone sclerosis.
Hip dysplasia radiographic evaluation
Norberg Angle for hip dysplasia: Normal >105°
Penn Hip for hip dysplasia
Obtains OA readings from the standard hip extended view, hip joint congruity from the compression view and quantitative measurements of hip joint laxity from the distraction view. It is accurate in puppies as young as 16 weeks of age. A dog with a DI<0.3 (femoral head comes out of the joint <30%) is unlikely to develop OA from hip dysplasia.
Aseptic necrosis of the femoral head
No sex predilection, 4-10mths, toy and small breed dogs.
Weight bearing lameness that is usually unilateral, pain on abduction of leg. Occurs as a result of primary necrosis of the capital femoral epiphysis.
Early, see linear radiolucency within subchondral bone of femoral head, areas of decreased opacity in femoral epiphysis and metaphysis. Flattening and irregularity of femoral head and neck.
Epiphyseal dysplasia
Abnoraml formation of the epiphysis in dogs with congenital hypothyroidism. Affected animals have dwarfed structure.
Rickets
Excessive growth of physeal cartilage, resulting from endochondral ossification failure on the metaphyseal side of the physis. Usually affects all physes, with widening and delayed ossification of the physis. Flaring of the metaphyses and may result in severe growth deformities.
Physeal growth plate injuries
No sex prediliction, skeletally immature (<10mths), any breed.
Trauma causing damage to the physis most common cause. Other conditions include; HOD, retained cartilagenous core, chondrodysplasias. These lead to asynchronous growth of ulna and radius causing angular limb deformities.
Trauma often leads to Salter-Harris physeal damage.
Premature closure of distal ulna bottom, radius right.
Feline capital physeal dysplasia
Males, 4-24mths, any breed. Most patients are reportedly overweight. Generally acute lameness because of secondary capital physeal fracture. Occurs as a result of disorganised growth of the physis that cannot resist shear forces of normal activity.
Radiographic features: may only see the capital physeal fracture, may see reabsorption of the femoral neck.
Osteochondroma
Small clusters of germinal physeal cells that grow away from the germinal layer can develop a secondary ossification centre. Generally located in the periphery of the physis. Consequently, a focal outgrowth of bone develops and as the bone lengthens eventually becomes located in the perimetaphyseal location. These stop growing when the physis close, as they are an aberrant growth centre.
Congenital monostotic bone cyst
Large radiolucent bone cyst, located within or adjacent to newly forming metaphyseal bone, seen in large giant breed dogs.
Panosteitis
Males, 5-12 months up to 7 years. Large and giant breed dogs, affecting long bones. Often associated with shifting leg lameness because multifocal lesions in multiple bones.
Early lesions have blurring and accentuation of trabercular bone, irregularity of endosteal surface, diminished cortico-medullary definition. Lesions often near nutrient foramina with a thumb like appearance. May coalesce to occupy most of the medullary cavity.
Hypertrophic osteodystrophy
No clear sex predilection, 2-6 months of age, large giant breeds. Self-limiting disease affecting the metaphyses of long bones. Metaphyseal regions may be swollen, warm and painful. Severe cases -> systemic illness, with fever, depression, anorexia, and reluctance to stand and walk.
Transverse radiolucent lines in the metaphyses, parallel and adjacent to physis.
Metaphyseal flaring and sclerosis may occur. Periosteal ‘cuffong’ at the metaphysis develops as disease progresses.
Retained endochondral cartilagenous core
6-12 months, large and giant breeds. Often an incidental finding with no clinical lameness. Can result in asynchronous growth of radius and ulna. Resulting in elbow subluxation and angular limb deformities.
Inverted conical shaped radiolucent zone extending from the disal ulnar physis into the distal ulnar metaphysis. Smoothly marginated and symmetrical in asymptomatic patients.
Patellar luxation/subluxation
Young immature dogs, intermittent signs make animals not present until later. Toy/small breed occasionally larger breeds.
Skipping or intermittent carrying of limb with flexed stifle. Predilection; abnormal femoral neck angles, lateral bowing of femur, hypoplastic medial femoral condyle, displacement or rotation of the tibial tuberosity and crest, shallow trochlear groove and rotation of distal femur, medial luxation (most common). Difficult to see on radiographs as it intermittently luxates. Need a skyline to assess.
