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Musculoskeletal Radiography. Dr. LeeAnn Pack Dipl. ACVR. Osteoarthritis. Occur when supra-physiologic /biomechanical stresses applied. Osteophytes – Intra-capsular periosteal new bone that usually begins at chondrosynovial junction (peri-articular).
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Musculoskeletal Radiography Dr. LeeAnn Pack Dipl. ACVR
Osteoarthritis • Occur when supra-physiologic /biomechanical stresses applied. • Osteophytes – Intra-capsular periosteal new bone that usually begins at chondrosynovial junction (peri-articular). • Enthesophytes – Periosteal new bone at origin or insertion of tendon, ligament or muscle. Can also occur at joint capsule attachment.
Degenerative joint disease • 1. Intra-capsular soft tissue swelling • 2. Peri-articular osteophytes • 3. Enthesophytes • 4. Subchondral erosions • 5. Mineralized joint bodies • 6. Subchondral sclerosis • 7. Subchondral “cysts” • 8. Joint space narrowing 8
Degenerative Joint Disease • Intra-capsular swelling • Seen as a result of joint effusion or soft tissue proliferation
DJD - Hips • Peri-articular osteophytes
DJD Stifle • Peri-articular osteophytes
DJD – Radiographic Signs • Subchondral sclerosis results from bone formation and hypertrophy of the trabeculae adjacent to the joint • Also called sclerosis or eburnation • Secondary to increased biomechanical forces • Wolff’s Law – bone remodeling according to the forces acting upon it
DJD • Subchondral sclerosis
Elbow DJD • Note the large osteophyte on the anconeal process – this is often times one of the earliest changes seen with DJD in the elbow
DJD • Subchondral bone cysts are formed by proliferation of the synovium invading subchondral bone • Occurs in severe cases of DJD
DJD – Joint Mice • Joint mice are pieces of articular cartilage that have become detached and are in the joint – they mineralize when they have a blood supply – must R/O avulsion fragment
Enthesopathy Enthesiopathy of origin of coxus articularis m. • Enthesis - site of attachment of muscle, tendon or ligament to bone • Enthesiopathy – proliferation of bone at enthesis due to pulling of attachment • Another form of periosteal reaction Enthesiopathy of insertion of iliopsoas m.
Enthesiopathy • Periosteal response at the site of attachment of soft tissue to bone. • Tendon • Ligament • Muscle • Contrasts with osteophyte – an osseous outgrowth at the peri-articular margin.
DJD • Joint space alteration • Decreased size of joint due to destruction of the articular cartilage • Increased size of join space may be seen in acute injury with severe synovial effusion • Abnormal joint space width is best evaluated with weight bearing views • Stressed views can also be made
DJD • Narrowed joint space • Do not confuse for positioning error
Septic Arthritis • Radiographic signs • Bony lysis is often seen early in the disease process resulting in rough or irregular articular margins • multiple joint surfaces usu involved • The degree of subchondral erosion is much more severe than with just DJD • In chronic cases, periosteal reactions and osteophytes can be seen
Non-erosive Polyarthritis • Causes: • Idiopathic polyarthritis • Systemic lupus erythematosus • Arthritis assocaited with chronic infection • Polyarthritis/polymyositis syndrome • Plasmacytic/lymphocytic synovitis
Non-erosive Polyarthritis • Joints are normal except for effusion • Multiple sites are usually involved • Carpus, tarsus, stifle
Erosive Polyarthritis • Early changes • No radiographic signs are apparent early except for maybe intra-capsular swelling
Erosive Polyarthritis • Late changes • Formation of cystic lesions which progress to irregular erosions of the subchondral bone and marked destruction of the joint surfaces
Erosive Polyarthritis • Further late changes • Joint spaces may narrow due to loss of articular cartilage • Subluxation and luxation of the joints due to the destruction of the ligaments
Synovial Cell Sarcoma • Early in the disease there is intra-capsular and/or peri articular swelling • Swelling then turns to a mass effect • Later there is bone lysis of multiple bones of the joint
Differentials- Joints • Joint associated neoplasia • Asymmetrical intra-capsular soft tissue swelling (mass) • Multiple bones within joint affected (lysis) • Erosive poly-arthritis & septic arthritis (fungal) • Intra-capsular soft tissue swelling (usually symmetrical) • Typically multiple joints (depends on reason for septic arthritis) • Multiple bones within joint affected (lysis) • Non-erosive poly-arthritis • Typically multiple joints • Intra-capsular soft tissue swelling
Hypertrophic Osteopathy • Palisading periosteal response • Usually solid • Occurs secondary to a mass somewhere • Thoracic • GU tract • Fungal disease • Heartworm disease
HO • Begins on the abaxial digit and progresses proximal and axially
HO • Radiographs of the chest and abdomen should be made • And abdominal US can be preformed if needed
Cruciate Ligament Rupture • Cranial displacement of the infra-patellar fat pad • Caudal displacement of the fascial stripe
Cruciate Ligament Rupture • DJD • Base and apex of the patella • Proximal aspect of the trochlear ridge • Medial and lateral aspects of the distal femur and proximal tibia • fabellae
OCD Shoulder Elbow Stifle tarsus Retained Cartilage Core Fragmented Medial Coronoid Process Ununited Anconeal Process Panosteitis Hypertrophic Osteodystrophy Hip Dysplasia Legg-Calve-Perthes Developmental MS Diseases
Osteochondrosis • Dysfunction of endochondral ossification (bone that forms from cartilage) • Disturbance leads to increased thickness of the cartilage • Cartilage is radiolucent compared to bone therefore, radiographically we see a radiolucent subchondral defect
Osteochondrosis • Subchondral defect – flattening • Surrounding sclerosis as time progresses • Joint mice • Secondary DJD • Locations: shoulder, elbow, stifle, tarsus
Shoulder OCD • Subchondral defect on the caudal aspect of the humeral head • May see a joint mouse • May just be flattened • Secondary DJD • May need arthrogram or explore
Elbow OCD • Subchondral defect present on the distal medial aspect of the humerus (humeral condyle) • Surrounding sclerosis
Stifle OCD • Subchondral defect on the distal aspect of the lateral femoral condyle • Mineralized flap rarely seen • Joint effusion common • DJD develops • Do not confuse the extensor fossa for OCD
Tarsus OCD • Rotts! • Medial trochlear ridge of the talus • Often seen small mouse • Joint effusion • DJD • See best on oblique view or flexed lateral