Orthopedic Slides 4u3f9

INTRODUCTION TO ORTHOPAEDICS

WHAT DOES IT MEAN

• ORTHO=> STRAIGHT • PAEDICS=> CHILD

• photo

Types of Bone Introduction

•There are two types of bone • lamellar bone (normal bone including cortical and cancellous types) • woven bone (immature and pathologic bone)

Lamellar Bone

•Normal bone that is stress oriented. •Two types include • cortical • 80% of skeleton • characterized by slow turnover rate and high Young's modulus • made of packed osteons or Haversian systems • osteons • outer border defined by cement lines • Haversian canals (Volkmann's canals) connect osteons and haversian systems • contain arterioles, venules, capillaries, and nerves • cancellous ( spongy or trabecular bone) • lower Young's modulus and more elastic

Woven Bone

•Immature or pathologic bone that is woven and random and is not stress oriented •Compared to lamellar bone, woven bone has: • more osteocytes per unit of volume • higher rate of turnover •Weaker and more flexible than lamellar bone • not stress-oriented

Descriptive Orthopaedic • Valgus: part of body distal to t directed away from midline • Varus: Part of body distal to t directed toward midline

• • • • • •

Hallus Genu varus Genu valgus pes varus metatarus valgus metatarus varus

Which foot has a valgus deformity?

Hallus valgus

How do you describe this foot deformity?

CONGENITAL ANOMALIES

CONGENITAL ANOMALIES

CONGENITAL ANOMALIES

CONGENITAL ANOMALIES

CONGENITAL

musculoskeletal injuries • Fracture and dislocation

Stages of Fracture Healing

Inflammation

•Hematoma forms and provides source of hemopoieitic cells capable of secreting growth factors. •Fibroblasts and mesenchymal cells migrate to fracture site and granulation tissue forms around fracture ends • during fracture healing granulation tissue tolerates the greatest strain before failure •Osteoblasts and fibroblasts proliferate

Repair

•Primary callus forms within two weeks. If the bone ends are not touching, then bridging soft callus forms. •Enchondral ossification converts soft callus to hard callus (woven bone). Medullary callus also supplement the bridging soft callus •Type II collagen is produced early in fracture healing and then followed by type I collagen expression •Type X collagen types is expressed by hypertrophic chondrocytes as the extraarticular matrix undergoes calcification •Amount of callus is proportional to extent of immobilization • primary cotical healing occurs with rigid immobilization • enchondral healing with periosteal bridging occurs with closed treatment

Remodeling •

•Begins in middle of repair phase and continues long after clinical union •Shaped through • Wolff's law: bone remodels in response to mechanical stress Piezoelectic charges : bone remodels is response to electric charges: compression side is electronegative and stimulates osteoblast formation, tension side is electropostive and simulates osteoclasts

Compartment Syndrome • Pathophysiology local trauma and soft tissue destruction > bleeding and edema > increased interstitial pressure > reduced microvascular perfusion > macrovascular arterial occlusion > myoneural ischemia

Peripheral Nerves Injury

Peripheral Nerves Injury Mechanism of Nerve Injury

•Stretching injury • 8% elongation will diminish nerve's microcirculation • 15% elongation will disrupt axons • examples • "stingers" refer to neurapraxia from brachial plexus stretch injury • suprascapular nerve stretching injuries in volley ball players • correction of valgus in TKA leading to peroneal nerve palsy •Transection • sharp transections have better prognosis than crush injuries

Nerve Injury Classification (Seddon, 1943) •Neurapraxia (1st degree) • nerve contusion leading to reversible conduction block without Wallerian degeneration • histology • histopathology shows focal demyelination of the axon sheath (all structures remain intact) • usually caused by local ischemia • electrophysiologic studies • nerve conduction velocity slowing or a complete conduction block • fibrillation potentials • positive sharp waves (PSW) • high amplitude - long duration MUPS • prognosis • recovery prognosis is excellent •Axonotmesis (2nd degree) • axon and myelin sheath disruption leads to conduction block with Wallerian degeneration • epineurium remains intact •Neurotmesis • complete nerve division with disruption of epineurium • no recovery unless surgical repair performed

Peripheral Nerves Injury

Type

Degr ee

Myelin Intact

Axon Intact

Epineurim Intact

Wallerian Degen.

Reversible

Neurapr axia

1st

No

Yes

Yes

No

reversible

Axonot mesis

2nd

No

No

Yes

Yes

reversible

Neurot mesis

3rd

No

No

No

Yes

irreversible

Pediatric • Developmental Dysplasia of the Hip

TEV

SCOLIOSIS

adult Reconstruction

Osteoarthritis • A form of noninflammatory arthriits – may represent failed attempt of chondrocytes to repair damaged cartilage – most common form of arthritis – knee is most commonly affected t

• Forms – primary (intrinsic defect) – secondary (trauma, infection, congenital)

Treatment •Nonoperative • NSAIDS, lifestyle modifications, physical therapy • indications • first line of treatment • techniques • therapy to maintain strength surrounding ts • weight loss has the strongest ing evidence as an effective nonoperative treatment for osteoarthritis of the knee • corticosteroid t injections • indications • no strong evidence s • viscoelastic t injections • indications • no strong evidence to •Operative • arthroscopic debridement • indications • rarely leads to long term benefits • high tibial osteotomy • indications • in younger patients to with knee arthritis to postpone need for t replacement • total t replacement • indications • indicated for advanced disease

Adult reconstruction

Sport med Rotator Cuff Muscles • Supraspinatus: Insertion Inferior facet on greater tuberosity of humerus • Infraspinatus:Insertion Inferior facet on greater tuberosity of humerus • Teres minor: Insertion Inferior facet on greater tuberosity of humerus • Subscapularis: Insertion Lesser tuberosity of humerus

Hand

PIP Swelling

Ulnar Deviation, M Swelling, Left Wrist Swelling

Paronychia • A painful nailfold infection – most common hand infection.

• Usually caused by staphylococcus aureus. – chronic cases that do not respond to antibiotics may be caused bycandida albicans (more common in diabetics)

Ganglion Cysts • A mucin filled synovial cyst caused by either – trauma – mucoid degeneration – synovial herniation

• Epidemiology – it is the most common hand mass (60-70%)

• Location – dorsal carpal (70%) • originate from SL ligament

– volar carpal (20%) • originate from radiocarpal

Carpal Tunnel Syndrome

• Most common compressive neuropathy

spine

Lumbar Disc Herniation • Epidemiology95% involve L4/5 or L5/S1 levels – L5/S1 most common level

• • • •

peak incidence is 4th and 5th decades only ~5% become symptomatic 3:1 male:female ratio Disc composition annulus fibrosis – composed of type I collagen, water, and proteoglycans – characterized by extensibility and tensile strength • high collagen / low proteoglycan ratio (low % dry weight of proteoglycans)

nucleus pulposus – composed of type II collagen, water, and proteoglycans – characterized by compressibility • low collagen / high proteoglycan ratio (high % dry weight of proteoglycans) – proteoglycans interact with water and resist compression

•

a hydrated gel due to high polysacharide content and high water content (88%)

Adolescent Idiopathic Scoliosis • Idiopathic scoliosis in children > 10 yrs – most common type of scoliosis

• Epidemiology – incidence of 3% for curves between 10 to 20° – incidence of 0.3% for curves > 30° – 10:1 female to male ratio for curves > 30° • 1:1 male to female ratio for small curves • right thoracic curve most common

oncology Age

Benign

Malignant

Birth to 5 years

Osteomyelitis Osteofibrous dysplasia

Metastatic rhabdomyosarcoma Metastatic rneuroblastoma Leukemia

Lesion in young patient (10-40 years)

Characteristic NOF Osteoid osteoma Giant cell tumor ABC UBC Osteochondroma & MHE Chondroblastoma Fibrous dysplasia

Osteosarcoma Ewing's Desmoplastic fibroma Leukemia Lymphoma

Destructive Osteomyelitis Eosinophillic granuloma Older patient (40-80 years)

Enchondroma Bone infarct Bone island Paget's disease Hyperparathyroidism

Metastatic bone disease Myeloma Lyphoma Chondrosarcoma MFH Secondary sarcoma (Paget's, irradiation)

oncology ORIGIN Osteogenic

Chondrogenic

Unknown origin Fibrogenic

BENIGN

Bone tumors Osteoid osteoma Parosteal osteosarcoma Osteoblastoma

Notochordal Lipogenic

HIGH GRADE • Periosteal osteosarcoma • Intramedullary osteosarcoma Dedifferentiated chondrosarcoma

Enchondroma Osteochondroma Chondroblastoma Chondromyoid fibroma

Chondrosarcoma

• Giant cell tumor • Histiocytoma • Nonossifying fibroma

• Adamantinoma

• Ewing's tumor

• Desmoplastic fibroma

• Fibrosarcoma

Hematopoietic

Vascular

LOW GRADE

• Hemangioma

• Lipoma

• Multiple myeloma • Lymphoma • Leukemia • Hemangioendothelio ma • Chordoma

Synovial

Soft tissue tumors • Giant cell tumor of tendon sheath

x

• Synovial sarcoma • Malignant giant cell tumor of tendon sheath • Fibrosarcoma • Myxofibrosarcoma • Malignant fibrous histiocytoma

Fibrogenic & Fibrohistiocytic

• Fibroma • Fasciitis (nodular or proliferative) • Fibrous histiocytoma

x

Lipogenic

• Lipoma

• Myxoid liposarcoma

Muscle tissue

• Leiomyoma • Rhabdomyoma

x

Vascular

• Hemangioma • Lymphangioma • Glomus tumor

x

• Lymphangiosarcoma • Hemangiosarcoma

Neurogenic

• Neuroma (traumatic or Morton's) • Neurilemoma (benign schwannoma) • Neurofibroma (neurofibromatosis)

x

• Malignant schwanoma • PNET tumors

• Pleomorphic liposarcoma • Leiomyosarcoma • Rhabdomyosarcoma

Histology Bone marrow aspiration and biospy required for diagnosis and staging

• Lymphoma • Ewings

Small round cell tumor

• Lymphoma • Leukemia • Ewing's sarcoma • Metastatic carcinoma (small cell lung) • Rhabdomyosarcoma • Neuroblastoma

Epithelial Glands seen on histology

• Synovial sarcoma (biphasic) • Metastatic carcinoma • Glomus tumor • Dedifferentiated chondrosarcoma • Synovial sarcoma • Osteosarcoma with chondroblastic features

Bimorphic histology

Multi-nucleated Giant cells present

Hemosiderin pigmentation

• Giant cell tumor • Chondroblastoma • Aneurysmal bone cyst • NOF • PVNS • UBC

Immunostains Leukocyte common antigen CD138 CD99 CD1A CD34 CD20 and CD45 (B cell) S100

• Lymphoma • Myeloma • Ewing's • EG • DFSP • Angiosarcoma • Lymphoma • EG • Chordoma • Melanoma • Clear cell sarcoma • Nerve sheath tumors (Schwanoma)

Elastin Keratin

• Elastofibroma • Metastatic bone disease • Synovial sarcoma • Chordoma • Epitheloid sarcoma • Adamantinoma

Factor VIII Smooth muscle actin Desmin Myoglobin CK7

• Angiosarcoma • Leiomyosarcoma • Rhabdomyosarcoma • Rhabdomyosarcoma • Breast CA • Lung CA • Ovarian CA • Colon CA • Lung CA

CK125 CK20 TTF1 Vimentin

• synovial sarcoma, rhabodymosarcoma, and leiomyosarcoma

EMA

• Synovial sarcoma

Radiographs "Bubbly" lesion on xray

NOF ABC UBC

Bone scan is cold

Multiple myeloma Melanoma

Well defined "punched out" lesion

Eosinophillic granuloma GiantCellTumor Multiple myeloma

infection • Pathogenesis: • hematogenous – – – – –

originated or transported by blood etiology of 20% of osteomyelitis vertebrae most common site S. aureus is most common infection

• contiguous-focus – associated with previous surgery, trauma, wounds, or poor vascularity – can be bacterial (most common), mycobacterial, or fungal in nature

• Radiographs: • orthogonal plain radiographs should be obtained first • often shows as a lytic region surrounded by an area of sclerosis • osteomyelitis is the "great imitator" - it can radiographically mimic almost all neoplastic processes • bone loss must be 30-40% before evident on plain films • sequestrum: devitalized bone that serves as a nidus for continual infection • involucrum: formation of new bone around an area of bony necrosis

infection Age group

Most common organisms

Newborns (younger than 4 mo)

S. aureus, Enterobacter species, and group A and B Streptococcusspecies

Children (aged 4 mo to 4 y)

S. aureus, group A Streptococcus species, Kingella kingae, andEnterobacter species

Children, adolescents (aged 4 y to adult)

S. aureus (80%), group A Streptococcus species, H. influenzae, andEnterobacter species

Adult

S. aureus and occasionally Enterobacter or Streptococcus species

Sickle Cell AnemiaPatients

S. aureus is typically most common, but Salmonella species is pathognomonic

Septic Arthritis • Most commonly affected ts in descending order include – knee > hip > elbow > ankle >stenoclavicular t (see below)

• Pathoanatomy – 3 main ways of bacterial seeding of t • bacteremia • direct inoculation from trauma or surgery • contiguous spread from adjacent osteomyelitis

– septic arthritis causes irreversible cartilage destruction in an involved t • release of proteolytic enzymes from inflammatory cells (PMNs) • cartilage injury can occur by 8 hours

• Most common pathogens include – staphylococcus species • staphyloccus aureus (most common, >50% cases) • MRSA • staphylococcus epidermis

– neisseria gonorrhea • most common organism in otherwise healthy sexually active adolescents and young adults • knee most commonly involved

– streptococcus – salmonella • seen in patients with sickle cell disease

– pseudomonas aeruginosa • seen in patient with history of IV drug abuse

– pasteurella multocida • seen in patients after dog or cat bite

– eikenella corrodens • seen in patients after human bite

– organism found in immunocompromised host • can include fungal, and candida common pathogens

Sternoclavicular (SC) t Septic Arthritis

•Found in IV drug s •Pseudomonas Aeruginosa was most common pathogen in 1980's. •Staphylococcus aureus is now the most common pathogen in all patients, including IV drug s.