INTRODUCTION TO ORTHOPAEDICS

WHAT DOES IT MEAN

ORTHO=> STRAIGHT PAEDICS=> CHILD

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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 Terms

Valgus: part of body distal to joint directed away from midline Varus: Part of body distal to joint 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 Neurapr axia Axonot mesis Neurot mesis

Degr ee 1st 2nd 3rd

Myelin Intact No No No

Axon Intact Yes No No

Epineurim Intact Yes Yes No

Wallerian Degen. No Yes Yes

Reversible reversible reversible 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 joint

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 joints weight loss has the strongest supporting evidence as an effective nonoperative treatment for osteoarthritis of the knee corticosteroid joint injections indications no strong evidence supports viscoelastic joint injections indications no strong evidence to support 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 joint replacement total joint 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, MCP 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 Birth to 5 years Benign Osteomyelitis Osteofibrous dysplasia Characteristic NOF Osteoid osteoma Giant cell tumor ABC UBC Osteochondroma & MHE Chondroblastoma Fibrous dysplasia 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) Malignant Metastatic rhabdomyosarcoma Metastatic rneuroblastoma Leukemia Osteosarcoma Ewing's Desmoplastic fibroma Leukemia Lymphoma

Lesion in young patient (10-40 years)

oncology
ORIGIN Osteogenic BENIGN LOW GRADE HIGH GRADE Periosteal osteosarcoma Intramedullary osteosarcoma Dedifferentiated chondrosarcoma Bone tumors Osteoid osteoma Parosteal osteosarcoma Osteoblastoma

Chondrogenic

Enchondroma Osteochondroma Chondroblastoma Chondromyoid fibroma Giant cell tumor Histiocytoma Nonossifying fibroma

Chondrosarcoma

Unknown origin Fibrogenic Hematopoietic

Adamantinoma Desmoplastic fibroma

Ewing's tumor Fibrosarcoma Multiple myeloma Lymphoma Leukemia Hemangioendothelio ma Chordoma

Vascular Notochordal Lipogenic

Hemangioma

Lipoma

Synovial

Soft tissue tumors Giant cell tumor of tendon sheath

Fibrogenic & Fibrohistiocytic

Fibroma Fasciitis (nodular or proliferative) Fibrous histiocytoma

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

Lipogenic
Muscle tissue

Lipoma
Leiomyoma Rhabdomyoma Hemangioma Lymphangioma Glomus tumor Neuroma (traumatic or Morton's) Neurilemoma (benign schwannoma) Neurofibroma (neurofibromatosis)

Myxoid liposarcoma
x

Pleomorphic liposarcoma Leiomyosarcoma Rhabdomyosarcoma

Lymphangiosarcoma Hemangiosarcoma Malignant schwanoma PNET tumors

Vascular

Neurogenic

Histology Bone marrow aspiration and biospy required for diagnosis and staging Small round cell tumor

Lymphoma Ewings

Lymphoma Leukemia Ewing's sarcoma Metastatic carcinoma (small cell lung) Rhabdomyosarcoma Neuroblastoma Synovial sarcoma (biphasic) Metastatic carcinoma Glomus tumor Dedifferentiated chondrosarcoma Synovial sarcoma Osteosarcoma with chondroblastic features Giant cell tumor Chondroblastoma Aneurysmal bone cyst NOF PVNS UBC

Epithelial Glands seen on histology

Bimorphic histology

Multi-nucleated Giant cells present

Hemosiderin pigmentation

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) Elastofibroma Metastatic bone disease Synovial sarcoma Chordoma Epitheloid sarcoma Adamantinoma Angiosarcoma Leiomyosarcoma Rhabdomyosarcoma Rhabdomyosarcoma Breast CA Lung CA Ovarian CA Colon CA Lung CA synovial sarcoma, rhabodymosarcoma, and leiomyosarcoma Synovial sarcoma

Elastin Keratin

Factor VIII Smooth muscle actin Desmin Myoglobin CK7 CK125 CK20 TTF1 Vimentin EMA

Radiographs "Bubbly" lesion on xray NOF ABC UBC Multiple myeloma Melanoma Eosinophillic granuloma GiantCellTumor Multiple myeloma

Bone scan is cold Well defined "punched out" lesion

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 Newborns (younger than 4 mo) Children (aged 4 mo to 4 y) Most common organisms S. aureus, Enterobacter species, and group A and B Streptococcusspecies 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 S. aureus is typically most common, but Salmonella species is pathognomonic

Sickle Cell AnemiaPatients

Septic Arthritis
Most commonly affected joints in descending order include
knee > hip > elbow > ankle >stenoclavicular joint (see below)

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

septic arthritis causes irreversible cartilage destruction in an involved joint

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) Joint Septic Arthritis

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