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HomeExam stuffsHigh Yields in Orthopedics |medical study notes

High Yields in Orthopedics |medical study notes

High Yields in orthopedics are the important contents for the revision for the exam point of view. orthopedics revision notes are the medical study notes, orthopedics notes for the exam study and also usmle study notes

High Yields in Orthopedics |medical study notes
High Yields in Orthopedics |medical study notes

High Yields in orthopedics

Infection in Orthopedics

Infection – Will affect the disc/joint space and both endplates/sides equally and evenly. Usually will not involve multiple levels.  discitis, osteomyelitis, or discogenic spondylitis.

Confirm infection on a lateral film 1-3 levels.
Commonly seen with the cutaneous interruption – puncture wounds, or post strep/staph infections

Sequestrum – Fragment of a necrosed bone that has become separated from surrounding bone.

Involucrum – Covering of newly formed bone enveloping the sequestrum with infection of the bone.

tuberculosis – Likes apices of the lungs, can have a calcified density in the lung field or miliary type lesions.
Can also produce lesions in the spleen. Cold abscess formation in the psoas muscle.

Pott’s = TB of the spine Gibbus formation with angular kyphosis.

Histoplasmosis – Eggshell calcification, coin-shaped lesion.

Metastasis – Bone tumor

Metastasis –>Will not enlarge bone

Blastic metastasis – An area of whitening that does not extend off the bone, disc spaces maintained, irregular borders, and trabecular bone mottled.

Prostate metastasis – Primarily blastic, likes the spine and pelvis. Midline calcification AP pelvis above pubic symphysis.

Lytic metastasis – Short zone of transition, extensive osteolysis. Look for missing pedicle w/o contralateral sclerosis. TS follow ribs to vertebral bodies looking for missing pedicles.

Multiple Myeloma – MC  malignant bone tumor. Bone scans are cold. MC sites spine, pelvis, skull, ribs, and scapula. Punched out lesions, raindrop skull, and vertebra plana.
Lab findings Bence Jones proteinuria and reversed AG ratio.

Osteosarcoma – Permeative or ivory medullary lesion in metaphysis of a long bone. Codman’s reactive triangle, sunburst response, cortical interruption with soft tissue mass formation – cumulus cloud appearance.

Chondrosarcoma – MC sites pelvis, proximal femur, and humerus.
Metaphyseal or diaphyseal lesions with ill defined margins, popcorn matrix calcification, laminated or spiculated periosteal response.

Ewings Sarcoma – MC sites long bones of the lower extremity and innominate.
The classic presentation is a permeative diaphyseal with an onion skin layering of the periosteum.
Cortical saucerization is a characteristic sign. MC 1 malignant bone tumor to metastasize to bone.

Fibrosarcoma – Highly destructive medullary lesion, lytic, and eccentrically placed in a long bone. Produces the largest soft tissue mass of all 1 malignant tumors, seldom has a periosteal response.

Giant Cell Tumor – Expansile destructive lesion, soap bubble appearance, at the end of long bones.
MC site metaphysis extending to a subarticular location, can affect the joints.

Osteochondroma – MC sites femur, humerus, tibia, pelvis ribs and scapula. Two types – sessile appear as asymmetric bumps lacking a stalk, and pedunculated appear as a lobulated cauliflower mass with a dense amorphous calcified cap.
Pedunculated also appear as coat hanger exostoses growing away from the joint space on the metaphysis. Often an asymptomatic, incidental finding

Hemangioma – Most common benign tumor of the spine, corduroy cloth vertebra. 1-2 vertebral levels.

Osteoid osteoma – Night pain relieved by aspirin. MC location in the cortex with a radiolucent nidus and surrounding reactive sclerosis. DDx: Brodie’s abscess.

Osteoblastoma -MC site neural arch of the spine, lesions radiolucent and expansile. Tubular bone lesions are metaphyseal or diaphyseal with a nidus 2cm and no reactive sclerosis.

Enchondroma – Most common benign tumor of the hand, geographic expansile lytic lesions of a phalanx.

Ollier’s disease = Multiple enchondromas.

Chondroblastoma – Most common seen in the epiphysis as an oval or round lytic lesion that can spread to metaphysis, fluffy cotton wool calcification of the matrix.

Simple bone cyst -unicameral bone cyst. An expansile geographic lesion that is pseudoloculated. The metaphyseal end is larger than the diaphyseal end creating a truncated cone appearance.
Usually Dx by spontaneous fracture.Fallen fragment sign. MC sites humerus and proximal femur.

Aneurysmal bone cyst – Expansile lesion in the long bones creating eccentric metaphyseal saccular
Cortical ballooning termed blown out appearance or finger in the balloon sign. Spinal lesions affect
the neural arch..

Non ossifying fibroma(NOF) and fibrous cortical defect(FCD) – Distal tibia
MC site for NOF, distal femur
MC site for FCD. Lesion is solitary, eccentric, radiolucent ovoid, and bubbly usually in metaphysis.
3cm = FCD, > 3cm = NOF.

Pedunculated Osteoma – Well circumscribed radiopaque lesion.
Common site – Paranasal sinuses.

Paget’s – AKA osteitis deformans. Ivory vertebra, blade of grass sign, cortical thickening, cotton wool skull, shepherd’s crook deformity, picture frame vertebra, saber shin deformity, protrusio acetabuli, bone expansion, increased hat size.
Lab Dx: Urinary hydroxyproline, alkaline phosphatase. Malignant degeneration to osteosarcoma.

Brim Sign – Thickening of the cortex at the pectineal line and the pelvic rim. Seen with Paget’s.

Fibrous dysplasia – Shepherd’s crook deformity, ground glass appearance, septations of bone giving cobweb appearance. Expansile lesions with cortical thinning. MC benign tumor of rib creating an extrapleural sign. Ring of sclerosis around a geographic lesion. AKA polyostotic fibrous dysplasia.

Skin lesion café-au-lait spots – the coast of Main appearance.
Monostotic Fibrous dysplasia – Short zone of transition, sclerotic ring often found in the neck of the femur.

DISH – Diffuse Idiopathic Skeletal Hyperostosis. Ossification of ALL with non-marginal syndesmophytes.
Disc spaces and facets are spared. Dx on lateral film, difficulty swallowing, can be associated with diabetes.
Syndesmophyte – Bony outgrowth or ossification of a ligament that attaches to bone.

Avascular Necrosis of Bones | Ortho Study Notes


AS – Ankylosing Spondylitis. Initial marginal pencil-thin syndesmophytes can cause sclerosing of posterior motor units. Syndesmophytes thicken with time, B/L SI joint obliteration, decreased chest expansion.

Anderson lesion – Fracture of pathologic calcification. Ex: Ankylosing spondylitis.
Osteopoikilosis – Widespread multiple circumscribed round or ovoid lesions of increased density.
AKA bone measles.

Osteopetrosis – Vertebra within a vertebra appearance, bone within a bone appearance.

Hyperparathyroidism – Rugger jersey sign, salt, and pepper skull, increased serum calcium. Sub-periosteal resorption on the radial side of the fingers with soft tissue calcification.

Pancreatic calcification – midline calcification frequently seen with alcoholics.

Sarcoidosis – Pulmonary signs include lymphadenopathy(1-2-3 sign, potato nodes), infiltrates and fibrosis.
Scleroderma – Acro-osteolysis, soft tissue retraction, calcification and tapered fingers.
CREST sign = Calcinosis, Raynauds phenomenon, Esophageal abnormalities, Scleroderma and telangiectasia.

Parasites – Multiple calcific densities in muscle tissue.

Gout – Increased uric acid concentration leading to deposition of crystals and tophi formation.
Overhanging edge sign, avascular necrosis, juxta- articular erosions. Grossly inflammatory condition works from outside into the joint space. AKA lumpy bumpy arthritis.

Sickle cell anemia – Endplate biconcavity of all vertebral levels.

Osteitis condensans ilii – Primarily multiparous females, bilateral dense iliac subchondral sclerosis.
Joint spaces normal. AKA hyperostosis triangularis ilii. Will often see paraglenoid sulcus.

Osteitis condensans pubis – Usually males, bilateral subchondral sclerosis of the pubic rami.

Klippel Feil Syndrome – Classic triad = Short webbed neck, low hairline, and decreased C/S ROM. Multiple congenitally blocked vertebra,

Sprengle’s Deformity – elevated scapula, and omovertebral bone.

Congenital fusion/blocked vertebra – Wasp waist deformity, remnant disc, one spinous process for levels of fusion. Usually have more than one fusion/irregularity. If disc bulges beyond anterior vertebral body line acquired condition = surgical.

Ivory vertebra – Blastic lesion, DDx:
Paget’s, Blastic mets, Hodgkin’s lymphoma.

Butterfly vertebra – AKA double hemivertebra. Figure eight.Hemivertebra – Congenital absence or
failure to develop half of a vertebra.
Commonly associated with scoliosis.

Facet tropism – Sometimes visible on AP film, evaluate with CT transverse view.

Lumbarization – First sacral segment does not fuse with the sacrum and forms a sixth lumbar vertebra.

Sacralization – Fusion of the fifth lumbar segment with sacrum.

Pedicle agenesis – Unilateral missing or small pedicle with sclerotic contralateral pedicle from increased loading.
Congenital hip dysplasia – Putti’s
Triad = small femoral head, shallow acetabulum, and superior/lateral dislocated femoral head.
Cleidocranial dysplasia – Skull = Wormian bones, hot cross bun sign, frontal bossing, and platybasia.
Thorax = anomalous clavicular development, scapula small, winged or elevated.
Knife clasp deformity – Elongated L5 spinous with spina bifuda occulta at S1 and pain with extension.
Fracture – Need to have pieces to diagnose.
Jefferson’s fracture – C1 compression fracture, unstable needs to be braced.

Hangman’s fracture – C2 decompression fracture, stable but needs bracing.

Odontoid fracture – Three types: apical, transverse at the base, and
transverse extending into the body of C2.
Chance fracture – Shear fracture of the vertebral body caused by automobile lap belt restraint.
Honda sign – Horizontal fracture through the sacrum that results in the appearance of the Honda shaped “H”.
Spondylolytic spondylolisthesis – Fracture of the pars interarticularis with anterior slippage of the
vertebral body.
Assess from posterior body line, CS with George’s line. LS Dx from oblique film with Scotty dog neck interruption.
Anterolisthesis – AKA spondylolisthes is. Anterior slippage of the vertebral body w/o fracture. Assessed with Meyerding grading scale: 0-25% = grade I, 25-50% = grade II, 50-75% = grade III, 75-99% = grade IV, 100% = spondyloptosis.
Napolean hat sign – AKA bowline of Brailsford, seen with advanced grade IV anterolisthesis or spondyloptosis.

Rib Fracture – Follow ribs two at a time checking for alteration in lines.
Primary location lateral aspect of film where ribs curve from posterior to anterior. Do not assess ribs on a lateral thoracic.
Compression fracture – Fracture of a vertebra by pressure along the long axis of the vertebral column. Can cause angular kyphosis in the thoracic spine. AP film look for hyper lateral flexion with height intact and increased width. Disc is relatively well maintained. AKA anterior wedging.
Avulsion fracture – Usually seen at anterior inferior aspect of vertebral body, not confined within outline of vertebral body.
Femur fracture – Subcapital, basocervical, intertrochanteric, or subtrochanteric. Pathological fractures usually subcapital or femoral neck.
Limbus vertebra – Located at the anterior superior vertebral margin.
Congenital anomaly containing cortical margins within confines of the vertebral body.
Anterior fat pad normally seen on an AP elbow, AKA sail sign. Posterior fat pad sign a more reliable indicator of fracture. In 90 % of adolescents posterior fat pad sign indicates fracture, MC site radial head.
Galeazzi fracture – Middle to distal 1/3 of the radius with dislocation of the distal radial/ulna joint.
Monteggia fracture – Proximal ulna with dislocation of the radius.
Colle’s fracture – Posterior distal radius.
Smith’s fracture – Anterior distal radius.
Boxer’s fracture – 2nd or 3rd metacarpal vs. Bar room fracture – 4th or 5th metacarpal.
Jones fracture – Fifth metatarsal.
March fracture – Stress fracture of metatarsal.
Diastatic fracture – Separation of a partially moveable joint. Ex: Fracture with separation of a suture.
Protrusio Acetabuli – Weakening/fracture of the acetabulum commonly seen with bone softening conditions like Paget’s, RA. BL protrusio acetabuli = Otto’s pelvis commonly seen with RA.

Terry Thomas sign – Separation of the scaphoid lunate articulation from lunate dislocation.
AKA David Letterman sign.

Pelligrini Stiedas Disease – Medial condyle injury of the knee with partial avulsion of the MCL with

Rheumatoid Arthritis – Lab: RA factor,
C-reactive protein, increased ESR.
Early radiographic signs MC seen in the hands and feet. Uniform loss of joint space. Hands all fingers affected starts in MCP joints = Haygarth’s nodes. Can also affect PIP = Bouchard’s nodes, but never DIPS.
BL and symmetrical distribution, periarticular soft tissue swelling, juxtaarticular osteoporosis,
periarticular erosions and cysts, with uniform loss of joint space. Ligament laxity predominantly in hands with ulnar deviation of the fingers. Rarely see subchondral sclerosis. Can affect SI unilaterally.
Pencil in cup deformity.
Whittled appearance to periarticular bone. DDx: SLE.

Osteoarthritis – AKA DJD. Progressive, non-inflammatory process.
Asymmetric distribution, non-uniform loss of joint space, osteophytes, subchondral sclerosis, subchondral cysts, facet arthrosis, IVF stenosis, disc height and vacuum sign.
UV arthrosis/facet arthrosis – C/S oblique, hourglass IVF = IVF encroachment.
Erosive OA – Inflammatory variant of DJD involving DIP’s and PIP’s.
Erosion’s = gull wing deformity, sclerosis, osteophytes, periostitis, ankylosis, and non-uniform loss of joint space.

Psoriatic arthritis – MC involves DIP’s, also interphalangeal and PIP’s with widened joint spaces, ray pattern, sausage digit due to increased swelling, pencil in cup deformity and rat bite erosions.

Reiter’s – Triad of conjunctivitis, urethritis and polyarthritis usually following sexual exposure. Lateral foot heel spurs, SI erosion and sclerosis often unilateral, spine nonmarginal syndesmophytes
Calcium pyrophosphate deposition disease AKA CPPD – Crystals deposited within the articular cartilage leading to thin linear cartilage calcification parallel to and separate from adjacent subchondral bone.

Osteochondritis dessicans – MC site is lateral aspect of the medial femoral condyle. Joint mouse.
Hydroxyapatite deposition disease
AKA HADD, calcific bursitis –
Calcification within a tendon, bursa,or other periarticular soft tissue. MC sites include shoulder, hip, and the cervical spine. Shoulder = clock dial positions 3 & 9 calcific bursitis, between 1 & 2 and 10 & 11 calcific tendonitis.
Synoviochondrometaplasia – Synonyms include joint mice, synovial chondromatosis, steochondromatosis,
and osteochondral loose bodies. MC
sites include knee, hip, ankle and hip. Can lead to formation of a
Baker’s cyst.
Baker’s cyst – Enlargement of the gastrocnemius-semimembranosus bursa, commonly seen in RA and synoviochondrometaplasia.
Charcot’s joint – AKA neurotrophic joint. Six D’s: Distension -from effusion, Density -subchondral sclerosis,
Debris-bony intraarticular fragments,
Dislocation,, Disorganizaton-bag of bones, and Destruction of articular bone. Lack of subjective and objective pain. Commonly seen with diabetes and syphilitic tabes.

Scheuermann’s disease – AKA juvenile kyphosis, vertebral epiphysitis. Dx
from lateral film, at least three contiguous vertebra, irregular endplates, decreased disc height, increased kyphosis. MC middle to lower T/S, primarily teenagers.
Myositis ossificans – Post traumatic calcification of muscular tissue.

Risser’s Sign – Diffusion of iliac crest apophysis, used to determine skeletal maturity. Maturation lateral to medial.

Eisenstein Sign – Canal stenosis viewed from lateral film, posterior body line to spinolaminar line.
Normal should be ½ or more than the width of the vertebral body.
Pedicogenic stenosis.

Chamberlain’s Line – Hard palate to the opisthion, > 5mm = to basilar invagination.

McGregor’s Line – Hard palate to the base of the occiput, > 7mm = to basilar invagination.
Martin’s Basilar Angle – Root of the nasion/sella turcica to the foramen magnum, 128-152. Check for platybasia.
McNabb Line – Facet imbrication, parallel to inferior endplate draw line posterior. Should not cross the superior articulating facet of the inferior vertebra. Lateral lumbar oblique view. Rostrocaudal migration.
Jackson’s cervical stress line – Flexion at C5/6, extension, and neutral at C4/5.
Ullmann’s Line – Draw a line perpendicular to the S1 endplate line, should not intersect L5 body. Indicates spondylolisthesis.

Klein’s Line – Used to Dx slipped femoral capital epiphysis.
C/S Gravity Line – Tip of odontoid to anterior C/7 vertebral body.
L/S Gravity Line – L3 body center vertical line to anterior 1/3 of sacral base. AKA Ferguson’s line.
Boehler’s angle of 35 degrees – Calcaneal compression fracture.
Eburnation – Laying down more bone.
Bony infarct – This leads to increased whitening of bone.
Aneurysm – This leads to decreased whitening of bone.
Staghorn calculi – Calcification in the renal calyces.
Silhouette Sign – Loss of the heart outline due to lung consolidation. Ex: Pneumonia with lobar consolidation.
Hahn’s venous fissure – Horizontal radiolucent cleft on lateral thoracic film.
Renal artery aneurysm – AP film lateral to the L2/3 vertebral bodies.
25% calcify a circular or ring-like pattern.
Pleural effusion – Best seen with the lateral decubitus view.
Lung Apices – Best seen on apical lordotic view.
Pneumothorax – PA chest, look at dark lung field first. The air in the pleural cavity, no vascular markings on side of the lesion.
Trachea pushed away from side of lesion
Atelectasis – Collapsed lung, trachea pulled toward side of lesion, no vascular markings on side of lesion.
Pneumoperitonium – Air in the abdomen, best seen with erect abdomen view.
Knee – Medial condyle extends distally past lateral condyle.
Y Epiphysis – Acetabulum.
Ischial pubic growth plate usually closes by age nine.
Isthmic spondyolisthesis – Greatest degree of slippage occurs during 2-10 years old.
Medial oblique – View taken to visualize the proximal talofibular joint.
AP Coccyx – Caudal tube tilt.
Dorsiplantar foot – 5 degree cephalad tube tilt.
L/S IVF – Seen on the lateral film.
ADI – Assess from lateral cervical
films. Adult up to 3mm, children up to 5mm.
Lateral flexion film – Tuck chin in and flex to chest.
Facet dislocation – AKA facet perching. Ligamentous instability of posterior motor unit.
Geographic lesion – Circumscribed and uniformly lytic lesion.
MRI – T1 weighted = fat weighted = whiter fatty structures. T2 weighted = water weighted = whiter water based structures. Cortical bone is black on MRI.
CT – Used to study bone, chest or abdomen.
LCP – Pseudo widening of the joint
space, flattening and fragmentation of the femoral head.
Legg Calve Perthes Slipped Femoral
Capital Epiphysis
3-12 YO, especially 5-7 10-15 YO
5:1 male Increased in males
Limp with vague pain especially Limp with hip pain to knee of obese with abduction and int rot.
adolescent. Femur displaces sup, ext rot,
AKA avascular necrosis of femoral head adduction of the neck on the head.
Subchondral fracture (crescent sign)
Dx with Klein’s line on AP view
1 cause obscure – hereditary, trauma, 50% have a Hx of significant trauma endocrine, inflammatory, nutritional. Also assoc with rickets & osteodistrophy
10% bilateral 20-30% bilateral
Fabella – Sesamoid bone found in the lateral head of the gastrocnemius tendon proximally.
Capitulum – Distal humerus ,articulates with the radial head.
Olecranon fossa – Posterior distal humerus, accepts olecranon process of the ulna.
Coronoid process – Located on the anterior ulna, articulates with the trochlea.
Coracoid process – Located on the scapula.
Supracondylar fossa – Located on the humerus.
Supraglenoid sulcus – Located on the humerus.
Paraglenoid sulcus – Female pelvis lateral to SI joints, usually postpartum.
Os trigonum – Accessory ossicle posterior to the tibia, superior to the calcaneus.
Os vesalianum – Sesamoid bone proximal to the fifth metatarsal.
Megenblase – Stomach gas magenblase syndrome excessive gas in the stomach, owing
to habitual taking in of air with the food.
Paraglenoid sulcus
Supraglenoid sulcus humerus
The fabella sign is displacement of the fabella that is seen in cases of synovial effusion and popliteal fossa masses. The fabella is a sesamoid bone located inside the gastrocnemius lateral head tendon on the posterior side of the knee, in about 25% of people.
Fabella sesamoid bone on lateral side of gastrocnemius joint locking is a symptom of pathology in a joint . Joint locking is a common symptom of:
Osteochondritis dissecans
Synovial osteochondromatosis
Causes of joint locking include “joint mice Myositis ossificans comprises two syndromes
characterized by heterotopic ossification (calcification) of muscle.
Fallen fragment sign – the presence of a bone fragment in the dependent portion of a lucent bone
lesion. It is said to be pathognomonic of a simple (unicameral) bone cyst finger in a balloon.”sign

aneurism bone cyst ABC
distal femur reveals a wedge- or V-shaped area of radiolucency in the diaphysis (arrows);
this lucency represents the blade of grass sign and is indicative of active Paget disease gull-wing appearance Central erosion proximally with marginal proliferation distally at both the DIP and PIP joints
Gull-wing configuration is not specific for erosive osteoarthritis


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