Orthopedic Surgery Flashcards
What is ORIF?
Open Reduction Internal Fixation
What is ROM?
Range Of Motion
What is FROM?
Free Range Of Motion
What is ACL?
Anterior Cruciate Ligament
What is PCL?
Posterior Cruciate Ligament
What is MCL?
Medial Collateral Ligament
What is PWB?
Partial Weight Bearing
What is FWB?
Full Weight Bearing
What is WBAT?
Weight Bearing As Tolerated
What is THA?
Total Hip Arthroplasty
What is TKA?
Total Knee Arthroplasty
What is THR?
Total Hip Replacement
What is TKR?
Total Knee Replacement
What is PROM?
Passive Range Of Motion
What is AROM?
Active Range Of Motion
What is AFO?
Ankle Foot Orthotic
What is AVN?
AVascular Necrosis
What is supination?
Palm up
What is pronation?
Palm down
What is plantarflexion?
Foot down at ankle joint
What is foot dorsiflexion?
Foot up at ankle joint
What is adduction?
Movement toward the body
What is abduction?
Movement away from the body
What is inversion?
Foot sole faces midline
What is eversion?
Foot sole faces laterally
What is volarflexion?
Hand flexes at wrist joint toward flexor tendons
What is wrist dorsiflexion?
Hand flexes at wrist joint toward extensor tendons
What is allograft bone?
Bone from human donor other than patient
What is a reduction?
Maneuver to restore proper alignment to fracture or joint
What is a closed reduction?
Reduction done without surgery (e.g. casts, splints)
What is an open reduction?
Surgical reduction
What is a fixation?
Stabilization of a fracture after reduction by means of surgical placement of hardware that can be external or internal (e.g. pins, plates, screws)
What is a tibial pin?
Pin placed in the tibia for treating femur or pelvic fractures by applying skeletal traction
What is an unstable fracture or dislocation?
Fracture or dislocation in which further deformation will occur if reduction is not performed
What is varus?
Extremity abnormality with apex of defect pointed away from midline
What is valgus?
Extremity abnormality with apex of defect pointed towards midline
What is a dislocation?
Total loss of congruity and contact between articular surfaces of a joint
What is a subluxation?
Loss of congruity between articular surfaces of a joint, though articular contact still remains
What is arthroplasty?
Total joint replacement (most last 10-15 years)
What is arthrodesis?
Joint fusion with removal of articular surfaces
What is osteotomy?
Cutting bone (usually wedge resection) to help realigning of joint surfaces
What is non-union?
Failure of fractured bone ends to fuse
What is the diaphysis of a bone?
Main shaft of long bone
What is the metaphysis of a bone?
Flared end of long bone
What is the physis of a bone?
Growth plate, found only in immature bone
How should fractured extremities be examined?
- Observe entire extremity (e.g. open, angulation, joint disruption)
- Neurologic (sensation, movement)
- Vascular (e.g. pulses, cap refill)
Which x-rays should be obtained for a fractured extremity?
Two views (also joint above and below fracture)
How are fractures described?
- Skin status (open or closed)
- Bone (by thirds: proximal/middle/distal)
- Pattern of fracture (e.g. comminuted)
- Alignment (displacement, angulation, rotation)
How do you define the degree of angulation, displacement, or both?
Define lateral/medial/anterior/posterior displacement and angulation of the distal fragment(s) in relation to the proximal bone
What is a closed fracture?
Intact skin over fracture/hematoma
What is an open fracture?
Wound overlying fracture, through which fracture fragments are in continuity with outside environment.
High risk of infection.
What is a simple fracture?
One fracture line, two bone fragments
What is a comminuted fracture?
Results in more than two bone fragments, i.e. fragmentation
What is a segmental fracture?
Two complete fractures with a segment in between
What is a transverse fracture?
Fracture line perpendicular to long axis of bone
What is an oblique fracture?
Fracture line creates an oblique angle with long axis of bone
What is a spiral fracture?
Severe oblique fracture in which fracture plane rotates along the long axis of bone.
Caused by twisting injury.
What is a longitudinal fracture?
Fracture line parallel to long axis of bone
What is an impacted fracture?
Fracture resulting from compressive force.
End of bone is driven into contiguous metaphyseal region without displacement.
What is a pathologic fracture?
Fracture through abnormal bone (e.g. tumor-laden or osteoporotic bone)
What is a stress fracture?
Fracture in normal bone from cyclic loading on bone
What is a greenstick fracture?
Incomplete fracture in which cortex on only one side is disrupted.
Seen in children.
What is a torus fracture?
Impaction injury in children in which cortex is buckled but not disrupted
What is an avulsion fracture?
Fracture in which tendon is pulled from bone, carrying with it a bone chip
What is a periarticular fracture?
Fracture close to but not involving the joint
What is an intra-articular fracture?
Fracture through the articular surface of a bone
What is Colles’ fracture?
Distal radius fracture with dorsal displacement and angulation, usually from falling on an outstretched hand
What is Smith’s fracture?
Distal radius fracture with volar displacement and angulation, usually from falling on the dorsum of the hand
What is Jones’ fracture?
Fracture at the base of the 5th metatarsal diaphysis
What is Bennett’s fracture?
Fracture-dislocation of the base of the 1st metacarpal with disruption of the carpometacarpal joint
What is a boxer’s fracture?
Fracture of the metacarpal neck, classically of the 5th digit
What is a nightstick fracture?
Ulnar fracture
What is a clay shoveler’s avulsion fracture?
Fracture of spinous process of C6-C7
What is a hangman’s fracture?
Fracture of the pedicles of C2
What is a transcervical fracture?
Fracture through the neck of the femur
What is a tibial plateau fracture?
Intra-articular fracture of the proximal tibia (the plateau is the flared proximal end)
What is a Monteggia fracture?
Fracture of the proximal third of the ulna with dislocation of the radial head
What is a Galeazzi fracture?
Fracture of the radius at the junction of the middle and distal thirds accompanied by disruption of the distal radioulnar joint
What is a Pilon fracture?
Distal tibial fracture
What is Pott’s fracture?
Fracture of distal fibula
What is Pott’s disease?
Tuberculosis of the spine
What are the major orthopedic emergencies?
- Open fractures or dislocations
- Vascular injuries
- Compartment syndrome
- Neural compromise
- Osteomyelitis or septic arthritis
- Hip dislocations
- Exsanguinating pelvic fracture
What is the main risk when dealing with an open fracture?
Infection
Which fracture has the highest mortality?
Pelvic fracture (up to 50% if open)
What 3 factors determine the extent of injury of a fracture?
- Age (suggests susceptible point in MS system)
- Direction of forces
- Magnitude of forces
What are indications for open reduction of a fracture?
NO CAST: Non-union Open fracture Compromise of blood supply Articular surface malalignment Salter-Harris grade III-IV fracture Trauma patients who need early ambulation
What is a grade I open fracture?
What is a grade II open fracture?
> 1-cm laceration, minimal soft tissue damage
What is a grade IIIa open fracture?
Massive tissue devitalization or loss, contamination
What is a grade IIIb open fracture?
Massive tissue devitalization or loss and extensive periosteal stripping, contamination, inadequate tissue coverage
What is a grade IV open fracture?
Major vascular injury requiring repair
What are the 5 steps in the initial treatment of an open fracture?
- Prophylactic antibiotics to include IV gram-positive +/- anaerobic coverage (cefazolin, cefoxitin/gentamicin).
- Surgical debridement.
- Inoculation against tetanus.
- Lavage wound
What structures are at risk with a humeral fracture?
Radial nerve, brachial artery
What must be done when both forearm bones are broken?
Because precise movements are needed, open reduction and internal fixation are musts
How have femoral fractures been repaired traditionally?
Traction for 4-6 weeks
What is the newer technique to repair femoral fractures? What are its advantages?
Intramedullary rod placement.
Nearly immediate mobility with decreased morbidity/mortality.
What is the chief concern following tibial fractures?
Recognition of associated compartment syndrome
What is suggested by pain in the anatomic snuff-box?
Fracture of scaphoid bone
What is the most common cause of a pathologic fracture in adults?
Osteoporosis
What is acute compartment syndrome?
Increased pressure within a osteofacial compartment that can lead to ischemic necrosis
How is compartment syndrome diagnosed?
Clinically, using intracompartmental pressures is also helpful (> 40 mmHg requires fasciotomy)
What are the causes of compartment syndrome?
Fractures, vascular compromise, reperfusion injury, compressive dressings.
Can occur after any musculoskeletal injury.
What are common causes of forearm compartment syndrome?
Supracondylar humerus fracture, brachial artery injury, radius or ulna fracture, crush injury
What is Volkmann’s contracture?
Final sequela of forearm compartment syndrome.
Contracture of the forearm flexors from replacement of dead muscle with fibrous tissue.
What is the most common site of compartment syndrome?
Calf (4 compartments: anterior, lateral, deep posterior, superficial posterior compartments)
What 4 situations should immediately alert one to be on the lookout for a developing compartment syndrome?
- Suprcondylar elbow fracture in children
- Proximal or midshaft tibial fracture
- Electrical burn
- Arterial or venous disruption
What are the symptoms of compartment syndrome?
Pain, paresthesias, paralysis
What are the signs of compartment syndrome?
Pain on passive movement (out of proportion to injury), cyanosis or pallor, hypoesthesia (decreased sensation, decreased 2-point discrimination), firm compartment
Can a patient have a compartment syndrome with a palpable or Doppler-detectable distal pulse?
Yes
What are the possible complications of compartment syndrome?
Muscle necrosis, nerve damage, contracture, myoglobinuria
What is the initial treatment of the orthopedic patient developing compartment syndrome?
Bivalve and split casts, remove constricting clothes and dressings, place extremity at heart level
What is the definitive treatment for compartment syndrome?
Fasciotomy within 4 hours, if possible
What motor and sensation tests are used to assess the radial nerve?
Motor: wrist extension.
Sensation: dorsal web space, between thumb and index finger.
What motor and sensation tests are used to assess the ulnar nerve?
Motor: little finger abduction.
Sensation: little finger-distal ulnar aspect
What motor and sensation tests are used to assess the median nerve?
Motor: thumb opposition or thumb pinch
Sensation: index finger-distal radial aspect
What motor and sensation tests are used to assess the axillary nerve?
Motor: arm abduction
Sensation: deltoid patch on lateral aspect of upper arm
What motor and sensation tests are used to assess the musculocutaneous nerve?
Motor: elbow flexion
Sensation: lateral forearm
How is a peripheral nerve injury treated?
Controversial, although clean lacerations may be repaired primarily.
Most injuries are followed for 6-8 weeks with EMG.
What fracture is associated with a calcaneus fracture?
L-spine fracture (usually from a fall)
What are the nerves of the brachial plexus?
A.M. RUM:
Axillary, Median, Radial, Ulnar, Musculocutaneous
What are the 2 indications for operative exploration with a peripheral nerve injury?
- Loss of nerve function after reduction of fracture.
2. No EMG signs of nerve regeneration after 8 weeks (nerve graft).
What is the most common type of shoulder dislocation?
95% are anterior (posterior are associated with seizures or electrical shock)
Which 2 structures are at risk in a shoulder dislocation?
- Axillary nerve
2. Axillary artery
How is a shoulder dislocation diagnosed?
Indentation of soft tissue beneath acromion
What are the 3 treatment steps for a should dislocation?
- Reduction via gradual traction
- Immobilization for 3 weeks in internal rotation
- ROM exercises
What is the most common type of elbow dislocation?
Posterior
Which 3 structures are at risk in an elbow dislocation?
- Brachial artery
- Ulnar nerve
- Median nerve
What is the treatment for an elbow dislocation?
Reduce and splint for 7-10 days
When should hip dislocations be reduced?
Immediately, to decrease risk of avascular necrosis
What is the most common cause of a hip dislocation?
High velocity trauma
What is the most common type of hip dislocation?
Posterior (often involves fracture of posterior lip of acetabulum)
Which structures are at risk in a hip dislocation?
- Sciatic nerve
2. Blood supply to femoral head
What is the treatment for a hip dislocation?
Closed or open reduction
What are the common types of knee dislocations?
Anterior or posterior
Which structures are at risk in a knee dislocation?
- Popliteal artery and vein
- Peroneal nerve
- ACL
- PCL
What is the treatment for a knee dislocation?
Immediate attempt at relocation, arterial repair, ligamentous repair
What are the 5 ligaments of the knee?
- Anterior cruciate ligament
- Posterior cruciate ligament
- Medial collateral ligament
- Lateral collateral ligament
- Patellar ligament
What is the Lachman test for a torn ACL?
Thigh is secured with one hand while the other hand pulls the tibia anteriorly
What is the meniscus of the knee?
Cartilage surface of the tibia plateau (lateral and medial meniscus).
Tears are repaired usually by arthroscopy with removal of torn cartilage fragments.
What is McMurray’s sign?
Medial tenderness of knee with flexion and internal rotation of the knee.
Seen with a medial meniscus tear.
What is the unhappy triad?
Lateral knee injury resulting in:
- ACL tear
- MCL tear
- Medial meniscus tear
What is a locked knee?
Meniscal tear that displaces and interferes with the knee joint and prevents complete extension
What is a bucket-handle tear?
Meniscal tear longitudinally along contour of normal “C” shape of the meniscus
In collateral ligament and menisci injuries, which are more common, the medial or the lateral?
Medial
What are the signs of an Achilles tendon rupture?
Severe calf pain; bruised swollen calf; two ends of ruptured tendon may be felt; weak plantar flexion from great toe flexors that should be intact
What is the test for an intact Achilles tendon?
Thompson’s test:
Squeeze of the gastrocnemius muscle results in plantar flexion of the foot.
What is the treatment for an Achilles tendon rupture?
Young: surgical repair
Old: Many can be treated with progressive splints
What 4 muscles form the rotator cuff?
SITS:
- Supraspinatus
- Infraspinatus
- Teres minor
- Subscapularis
When do rotator cuff tears usually occur?
5th decade
What is the usual history for a rotator cuff tear?
Intermittent should pain especially with overhead activity, followed by an episode of acute pain corresponding to a tendon tear.
Weak abduction.
What is the treatment for a rotator cuff tear?
Usually symptomatic pain relief.
Later, if poor muscular function persists, surgical repair is indicated.
What is Dupuytren’s contracture?
Thickening and contracture of palmar fascia.
Incidence increases with age.
What is Charcot’s joint?
Joint arthritis from peripheral neuropathy
What is tennis elbow?
Tendonitis of the lateral epicondyle of the humerus.
Classically seen in tennis players.
What is turf toe?
Hyperextension of the great toe (tear of the tendon of the flexor hallucis brevis).
Classically seen in football players.
What are shin splints?
Exercise-induced anterior compartment hypertension (compartment syndrome).
Seen in runners.
What is a heel spur?
Plantar fasciitis with abnormal bone growth in the plantar fascia.
Classically seen in runners and walkers.
What is Kienbock’s disease?
Avascular necrosis of the lunate
What is traumatic myositis?
Abnormal bone deposit in a muscle after blunt trauma deep muscle contusion
How does a cast saw cut the cast but not the underlying skin?
It is an oscillating saw that goes back and forth cutting anything hard while moving the skin back and forth without injuring it
What is osteomyelitis?
Inflammation or infection of bone marrow and adjacent bone
What are the most likely causative organisms in osteomyelitis?
Neonates: Staph aureus, Strep Children: Staph aureus, H. flu, Strep Adults: Staph aureus Immunocompromised: Staph aureus, gram-negatives Sickle cell: Salmonella
What is the most common organism isolated in osteomyelitis in the general adult population?
Staph aureus
What is the most common organism isolated in osteomyelitis in patients with sickle cell disease?
Salmonella
What is seen with osteomyelitis on physical exam?
Tenderness, decreased movement, swelling
What are the diagnostic steps for osteomyelitis?
H&P, needle aspirate, blood cultures, CBC, ESR, bone scan
What are the treatment options for osteomyelitis?
Antibiotics +/- surgical drainage
What is a Marjolin’s ulcer?
Squamous cell carcinoma that arises in a chronic sinus from osteomyelitis
What is septic arthritis?
Inflammation of a joint beginning as synovitis and ending with destruction of articular cartilage if left untreated
What are the causative agents with septic arthritis?
Same as osteomyelitis, except that gonococcus is a common agent in the adult population
What are the findings on physical exam with septic arthritis?
Joint pain, decreased motion, joint swelling, joint warm to the touch
What are the diagnostic steps for septic arthritis?
Needle aspirate, x-ray, blood cultures, ESR
What is the treatment for septic arthritis?
Decompression of the joint via needle aspiration and IV antibiotics.
Hip, shoulder, and spine must be surgically incised, debrided, and drained.
What is the most common type of orthopedic tumor in adults?
Metastatic
What are the common sources of orthopedic tumors?
Breast, lung, prostate, kidney, thyroid, multiple myeloma
What is the usual presentation of an orthopedic tumor?
Bone pain or as a pathologic fracture
What is the most common primary malignant bone tumor?
Multiple myeloma
What is the differential diagnosis of a possible bone tumor?
Metastatic disease; primary bone tumor; metabolic disorder (hyperparathyroidism); infection
What are the 8 benign bone tumors?
Osteochondroma; enchondroma; unicameral/aneurysmal bone cyst; osteoid osteoma; chondroblastoma; fibroxanthoma; fibrous dysplasia; non-ossifying fibroma
What are the 7 malignant bone tumors?
Multiple myeloma; osteosarcoma; chondrosarcoma; Ewing’s sarcoma; giant cell tumor; malignant melanoma; metastatic
What is the difference in bone reaction from benign and malignant bone tumors?
Benign: Sclerotic bone reaction
Malignant: Little reaction
Are most pediatric bone tumors benign or malignant?
80% are benign
Are most adult bone tumors benign or malignant?
66% are malignant
What are the 4 diagnostic steps for bone tumors?
- Physical and lab tests
- Radiographs
- CT, technetium scan
- Biopsy
What are the radiographic signs of malignant bone tumors?
Large size; aggressive bone destruction; poorly defined margins; ineffective bone reaction to tumor; extension to soft tissues
What are the radiographic signs of benign bone tumors?
Small size; well-circumscribed; sharp margins; effective bone reaction to the tumor; no extension
What are specific radiographic findings with osteosarcoma?
Sunburst pattern
What are specific radiographic findings with Ewing’s sarcoma?
Onion skinning
What are specific radiographic findings with fibrous dysplasia?
Bubbly lytic lesion, ground glass
What is the mainstay of treatment for bone tumors?
Surgery (excision and debridement) for both malignant and benign tumors.
XRT and chemotherapy as adjuvant therapy for many malignant tumors.
What is the usual age of presentation with osteosarcoma?
10-20 years
What is the gender distribution for osteosarcoma?
M > F
What is the most common location for osteosarcoma?
66% in the distal femur, proximal tibia
What is the radiographic sine qua non for osteosarcoma?
Bone formation somewhere within tumor
What is the treatment for osteosarcoma?
Resection (limb sparing if possible) and chemotherapy
What is the 5-year survival for osteosarcoma?
70%
What is the most common site of metastasis for osteosarcoma?
Lungs
What is the most common benign bone tumor?
Osteochondroma
What is a chondrosarcoma?
Malignant tumor of cartilaginous origin.
Presents in middle-aged and older patients and is unresponsive to chemotherapy and XRT.
What is the usual presentation of Ewing’s sarcoma?
Pain, swelling in involved area
What is the most common location for Ewing’s sarcoma?
Around the knee (distal femur, proximal tibia)
What is the usual age of presentation with Ewing’s sarcoma?
Evenly spread among those
What are the associated radiographic findings with Ewing’s sarcoma?
Lytic lesions with periosteal reaction termed “onion skinning”, which is calcified layering.
Central areas of tumor can undergo liquefaction necrosis, which may be confused with purulent infection.
What is the 5-year survival rate for Ewing’s sarcoma?
50%
How can Ewing’s sarcoma mimic the appearance of osteomyelitis?
Bone cysts
What is a unicameral bone cyst?
Fluid-filled cyst most commonly found in the proximal humerus in children 5-15 years
What is the usual presentation of a unicameral bone cyst?
Asymptomatic until pathologic fracture
What is the treatment for a unicameral bone cyst?
Steroid injections
What is an aneurysmal bone cyst?
Hemorrhagic lesion that is locally destructive by expansile growth, but does not metastasize
What is the usual presentation of an aneurysmal bone cyst?
Pain and swelling.
Pathologic fractures are rare.
What is the treatment for an aneurysmal bone cyst?
Curettage and bone grafting
Which arthritides are classified as degenerative?
Osteoarthritis, post-traumatic arthritis
What signs characterize osteoarthritis?
Heberden’s nodes; Bouchard’s nodes; symmetric destruction; usually hip, knee, spine
What are Bouchard’s nodes?
Enlarged PIP joints of the hand from cartilage or bone growth
What are Heberden’s nodes?
Enlarged DIP joints of the hand from cartilage or bone growth
What is post-traumatic arthritis?
Usually involves one joint of past trauma
What are the treatment options for degenerative arthritis?
- NSAIDs for acute flares, not long-term
- Local corticosteroid injections
- Surgery
What are the characteristics of rheumatoid arthritis?
Autoimmune reaction in which invasive pannus attacks hyaline articular cartilage. Rheumatoid factor (anti-IgG/IgM) in 80% of patients.
What is pannus?
Inflammatory exudate overlying synovial cells inside the joint
What are the classic hand findings with rheumatoid arthritis?
Wrist: radial deviation
Fingers: ulnar deviation
What are the surgical management options for joint or bone diseases?
- Arthroplasty
- Arthrodesis
- Osteotomy
What is the major difference between gout and pseudogout?
Gout: caused by urate deposition, negative birefringent, needle crystal.
Pseudogout: caused by calcium pyrophosphate positive birefringent square crystals.
What is a Charcot’s joint?
Arthritic joint from peripheral neuropathy
What are the major differences between pediatric and adult bones?
Children: increased bone flexibility and bone healing, physis is weak point
What types of fractures are unique to children?
Greenstick fractures, torus fractures, and fracture through physis
What does the Salter-Harris classification system describe?
Fractures in children involving physis
What is a Salter I fracture?
Through physeal plate only
What is a Salter II fracture?
Involves metaphysis and physis
What is a Salter III fracture?
Involves physis and epiphysis
What is a Salter IV fracture?
Extends from metaphysics through physis into epiphysis
What is a Salter V fracture?
Axial force crushes physeal plate
What acronym can help you remember the Salter classification?
SALTR: Separated Above Lower Through Ruined
Why is the growth plate of concern in childhood fractures?
Growth plate represents the weak link in the child’s musculoskeletal system.
Fractures involving the growth plate of long bones may compromise normal growth, so special attention should be given to them.
What is the chief concern when oblique or spiral fractures of long bones are seen in children?
Child abuse is a possibility
What is usually done during reduction of a femoral fracture?
Small amounts of overlap is allowed because increased vascularity from injury may make the affected limb longer if overlap is not present.
Treatment after reduction is a spica cast.
What is unique about ligamentous injury in children?
Most ligamentous injuries are actually fractures involving the growth plate
What two fractures have a high incidence of associated compartment syndrome?
- Tibial fractures
2. Supracondylar fractures of the humerus
What is the epidemiology of congenital hip dislocation?
F > M, firstborn children, breech
What percentage of congenital hip dislocations are bilateral?
10%
How is the diagnosis of congenital hip dislocation made?
Barlow’s maneuver, Ortolani’s sign, radiographic confirmation is required
What is Barlow’s maneuver?
Detects unstable hip.
Patient is placed in the supine position and attempt is made to push femurs posteriorly with knees at 90 degrees and hip will dislocate.
What is Ortolani’s sign?
Clunk produced by relocation of a dislocated femoral head when the examiner abducts the flexed hip and lifts the greater trochanter anteriorly.
Detects a dislocated hip.
What is the treatment for congenital hip dislocation?
Pavlik harness (maintains hip reduction with hips flexed at 100-110 degrees)
What is scoliosis?
Lateral curvature of a portion of the spine.
Nonstructural: corrects with positional change
Structural: does not correct
What are 3 treatment options for scoliosis?
- Observation
- Braces (Milwaukee brace)
- Surgery
What are the indications for surgery for scoliosis?
Respiratory compromise; rapid progression; curves > 40 degrees; failure of brace
What is Legg-Calve-Perthes disease?
Idiopathic avascular necrosis of femoral head in children
What is a slipped capital femoral epiphysis?
Migration of proximal femoral epiphysis on the metaphysis in children.
The proximal femoral epiphysis externally rotates and displaces anteriorly from the capital femoral epiphysis, which stays reduced in the acetabulum.
What is Blount’s disease?
Idiopathic varus bowing of tibia
What is nursemaid’s elbow?
Dislocation of radial head (from pulling toddler’s arm)
What is Little League elbow?
Medial epicondylitis
What is Osgood-Schlatter’s disease?
Apophysitis of the tibial tubercle resulting from repeated powerful contractions of the quadriceps.
Seen in adolescents with an open physis.