Transcript Bone Response to Disease VM855 Orthopedics Lecture 1
Small Animal Orthopedic Radiology
Lecture 4 – Fracture Complications Diseases Affecting the Joints VCA 341 Fall 2011 Andrea Matthews, DVM, Dip ACVR Assistant Professor of Radiology
Complications of Fracture Healing Malunion Delayed union Nonunion Viable Nonviable http://www.boingboing.net/images/_i_pix_2007_11_03_CatXrayES2311_800x521.jpg
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Complications of Fracture Healing Malunion Healed but in an abnormal anatomic position Malunion involving joints will lead to osteoarthrosis Many malunions in immature dogs are difficult to recognize after 6-12 months due to extensive remodeling 3
Complications of Fracture Healing Malunion 4
Complications of Fracture Healing Delayed union Fracture is healing but not as quickly as expected Duration compared to similar fractures and fixation Subjective assessment – healing is dependant on many factors 5
Complications of Fracture Healing Delayed union 6
Complications of Fracture Healing Causes of delayed union Severe soft tissue damage (poor blood supply) Distracted or over-riding fragments Improper or inadequate reduction or fixation Significant periosteal stripping Removal of large bone fragments Obstruction or destruction of blood supply by implant 7
Complications of Fracture Healing Nonunion Fracture that has not healed with no evidence of progression to bony union Different from delayed union in that healing will not proceed without intervention Often muscle atrophy and lameness Fragment motion may be present pseudoarthrosis Distal radius and ulna of small breed dogs one of most common sites 8
Complications of Fracture Healing Nonunion Viable • • Hypertrophic Oligotrophic Nonviable (uncommon) • • • • Dystrophic Necrotic Defect Atrophic 9
Complications of Fracture Healing Viable (reactive or vascular) nonunion 1.
2.
• • • • Hypertrophic Excessive lysis at fracture site Excessive, nonbridging callus formation (“elephant” or “horse foot”) Sclerosis of bone fragments Can have angular limb deformity • • Oligotrophic Little to no callus - Bridging of fracture fragments with fibrous tissue Difficult to differentiate from nonviable nonunions 10
Hypertophic Nonunion
Note the widening of the fracture gap 11
Hypertophic Nonunion
Note the excessive, non bridging callus 12
Hypertophic Nonunion
Note the sclerotic fracture ends 13
Oligotrophic Nonunion
Note the rounded fracture ends, sealed medullary cavity of the distal fragment and minimal callus formation Clin Tech Small Anim Pract 2004; 19:168-179 14
Complications of Fracture Healing Nonviable nonunion 1.
2.
3.
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Dystrophic Poor vascular supply to at least one fracture fragment Little to no callus; lucent fracture gap Necrotic Lack of blood supply causes sequestrum formation Bone fragment retains sharp edges and is sclerotic Defect Large fracture gap cannot be bridged by callus Atrophic Usually progression from one of the other types of nonunions Little to no callus, loss of vascularity, rounding of bone margins 15
Defect Nonunion
Note the lack of callus formation , resorption and sclerosis of the fracture margins as well as the widening of the fracture gap 16
Atrophic Nonunion
Note the large fracture gap, no callus, and varying degrees of sealing of the medullary cavities Clin Tech Small Anim Pract 2004; 19:168-179 17
Diseases Affecting the Joints
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Osteoarthrosis
Also known as Degenerative Joint Disease A non-inflammatory disorder of synovial joints = osteoarthrosis Osteoarthritis implies inflammation Slowly progressive degenerative condition Occurrence Most frequent in the weight bearing joints 19
Osteoarthrosis
Roentgen signs Intracapsular soft tissue swelling due to joint effusion and/or synovial proliferation Usually first pathologic change 20
Osteoarthrosis
Roentgen signs Periarticular osteophytes result from articular cartilage proliferation in the non-weight bearing areas of the joint Excessive cartilage proliferation outgrows its nutrient supply the cartilage dies it is invaded by vessels and replaced by bone seen radiographically 21
Osteoarthrosis
Roentgen signs Joint space alteration • Decreased size of joint space due to destruction of the articular cartilage • Alteration in joint space width is best demonstrated on weight bearing views Artificial narrowing of joint spaces • • Obliquity of joints Joints that are not in the center of the film 22
Osteoarthrosis
Apparent joint space narrowing Could be real…may be an artifact See of dogs leg is straight relative to plate to know if real… 23
Osteoarthrosis
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Osteoarthrosis
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Osteoarthrosis
Roentgen signs • Subchondral sclerosis results from trabecular hypertrophy, compression and collapse of weakened subchondral bone Also called eburnation Subchondral osteolysis caused by necrosis of the bone following loss of articular cartilage Subchondral bone cysts are formed by proliferation of synovium invading the subchondral bone 26
Osteoarthrosis
Subchondral osteosclerosis Subchondral osteolysis 27
Osteoarthrosis
Roentgen signs “Joint mice” or “joint bodies” are pieces of articular cartilage that detach and are free within the joint. They are visible radiographically when mineralized 28
Cranial Cruciate Ligament Rupture Anatomy and Function Medial aspect of lateral femoral condyle to intercondylar area of tibia Cranial cruciate ligament (CCL) prevents cranial displacement of the tibia, limits internal rotation of the tibia and prevents hyperextension of the stifle 29
Cranial Cruciate Ligament Rupture Occurrence Females > males Young athletic dogs and middle age, over-weight dogs Acute, non weight-bearing lameness Roentgen signs Tibia may be displaced cranially 30
Cranial Cruciate Ligament Rupture CCL rupture Normal 31
Cranial Cruciate Ligament Rupture Roentgen signs Intracapsular swelling • Effusion and/or synovial proliferation A – displacement of infrapatellar fat pad B – displacement of fascial planes caudal to joint 32
Cranial Cruciate Ligament Rupture Roentgen signs Secondary osteoarthrosis • Osteophytes on patella, adjacent to trochlear groove of femur, margins of tibial plateau and fabellae 33
Cranial Cruciate Ligament Rupture Roentgen signs May seen an avulsion fracture in the cranial joint space Avulsion fragment 34
Septic Arthritis
Occurrence Direct inoculation, extension from soft tissue or bone infections or hematogenous in origin Can also occur in conjunction with other systemic diseases (Mycoplasma, Leishmania, etc) Roentgen signs Early infection may show only soft tissue swelling Once bony changes are apparent, the degree of damage is significant 35
Septic Arthritis
Roentgen signs Osteolysis is often seen early in the disease process, resulting in rough or irregular articular margins Usually multiple joint surfaces involved Degree of subchondral erosion is much more severe than with osteoarthrosis In chronic cases, may see periosteal reaction and osteophytes 36
Septic Arthritis
Osteolysis of subchondral bone Columnar periosteal reaction Intracapsular swelling 37
Septic Arthritis
Osteolysis of subchondral bone and ulna Intracapsular swelling 38
Erosive Polyarthritis
Etiologies Rheumatoid arthritis • • Most common type in dogs Small breeds, especially Shetland sheepdog and poodle Polyarthritis of greyhounds Periosteal proliferative polyarthropathy (cats) • Older cats 39 http://www.gentlegiantsrescue.com/images/sheltie%202%20800.jpg
Erosive Polyarthritis
Roentgen signs Intracapsular soft tissue swelling only radiographic changes for first few weeks Cyst-like lucencies in the subchondral bone at the joint capsule attachments and later at the articular margins Destruction of joint surfaces 40
Erosive Polyarthritis
Roentgen signs Narrow joints spaces due to loss of articular cartilage Subluxation and luxation of the joints due to destruction of the ligaments Suspect rheumatoid arthritis radiograph both carpal and tarsal joints as well as any joint that is swollen and painful 41
Erosive Polyarthritis
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Non-Erosive Polyarthritis
Etiologies Systemic lupus erythematosus (SLE) Idiopathic polyarthritis Feline nonerosive polyarthritis Arthritis associated with chronic infection Polyarthritis/polymyositis syndrome Polyarthritis/meningitis syndrome Plasmacytic-lymphocytic synovitis 43 http://www.vetmed.wsu.edu/courses_vm551_crd/images/dle.JPG
Non-Erosive Polyarthritis
Roentgen signs Intracapsular swelling (joint effusion and/or increased synovial mass) No osteolysis is noted Multiple joints involved Common sites include carpus, tarsus and stifle joints 44
Non-Erosive Polyarthritis
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Neoplasia of the Joints
Occurrence Middle aged to older medium to large breed dogs Rare in the cat From undifferentiated mesenchymal cells of synovium Stifle and elbow are most commonly affected joints Roentgen signs • Early Intracapsular and/or extracapsular swelling • Later Can affect both sides of the joint due to secondary bone involvement Metastasis to regional lymph nodes and lungs 46
Neoplasia of the Joints
Synovial cell sarcoma 47
Neoplasia of the Joints
Most common joint neoplasia Histiocytic sarcoma Synovial myxoma Synovial cell sarcoma • • • • • • Other neoplastic conditions that can affect the joints Rhabdomyosarcoma Fibrosarcoma Chondrosarcoma Malignant fibrous histiocytoma Liposarcoma Undifferentiated sarcoma… 48
The End!
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