Random Flashcards
PMP22: What pediatric congenital disorder is associated with a mutation of this gene?
Charcot Marie Tooth
Charcot-Marie-Tooth disease is a sensory motor demyelinating neuropathy that is autosomal dominant and is often due to a mutation of PMP22 (peripheral myelin protein 22) located at Chromosome 17p12. Orthopaedic manifestations include progressive distal muscle wasting/weakness (especially peroneal muscles), areflexia, hammertoes, hip dysplasia, and cavovarus foot deformities. Low nerve conduction velocities with prolonged distal latencies are noted in the peroneal, ulnar, and median nerves. Nerve pathology can show simultaneous demyelinization and remyelinization. There are several subtypes of the disease, but diagnosis is made commonly by DNA testing for a duplication of a portion of chromosome 17. Other pediatric congenital disorders and their associated genetic defect include Duchenne’s/Becker’s muscular dystrophies (dystrophin), Limb-girdle dystrophies (sarcoglycan and dystroglycan complex), myotonic dystrophy (myotonin), and spinal muscular atrophy (Survival motor neuron protein).
Which of the following concepts regarding pediatric hips is true?
- The proximal femoral physis and greater trochanteric apophysis develop from different cartilaginous physes
- The proximal femoral physis grows at a rate of 9 mm per year
- Normal infant femoral anteversion is between 10-20 degrees
- The ossific nucleus of the proximal femur is visible on radiographs by 6 months of age in most children
- Slipped capital femoral epiphysis (SCFE) typically occurs through the zone of proliferation
4 is correct. The ossific nucleus of the proximal femur is visible on radiographs by 6 months of age in most children.
The proximal femoral physis and greater trochanteric apophysis develop from the same cartilage physis in the infant which undergoes apoptotic division in the child. The distal femoral physis (not proximal) grows at a rate of 9 mm per year. The normal infant femoral anteversion is between 30-40 degrees. SCFE typically occurs through the zone of hypertrophy, not the zone of proliferation.
Vitale and Skaggs review the history, diagnosis, treatment, and outcome of developmental dysplasia of the hip.
Wientroub and Gill review the use of ultrasonography in the diagnosis and prognosis of developmental dysplasia of the hip. They recommend detection with ultrasound because of the delayed femoral head ossification (~5 months) and discuss the cost ineffectiveness of routine screening of all newborns.
What is the most common radiographic finding in reflex sympathetic dystrophy (RSD) or complex regional pain syndrome of the knee? 1 patella baja 2 patella alta 3 patella osteopenia 4 generalized osteopenia 5 supracondylar stress fracture
- patella osteopenia
Reflex Sympathetic Dystrophy (RSD) of the knee is different than that of the upper extremity. Pain out of proportion to the initial injury is the hallmark symptom. Other features include vasomotor disturbances, delayed functional recovery and various associated trophic changes. The JAAOS article by Cooper et al states that patellar osteopenia “is the most common radiographic finding”. However, they go on to state that the most reliable diagnostic test is symptom relief after sympathetic blockade. The JBJS article by Cooper et al treated 14 patients with RSD of the knee with epidural blocks for 4 days. Eleven patients had complete resolution of their symptoms, and pain that was out of proportion to the severity of the injury was the most consistent finding. Katz et al reviewed 36 patients with RSD primarily affecting the knee. They found that injuries or operation about the patellofemoral joint triggered its onset in 64% of patients.
Which of the following muscles provide the primary deforming forces to Bennett and Rolando fractures (base of the 1st metacarpal fractures)
Abductor pollicis longus and adductor pollicis
A 45-year-old male presents with the fracture seen in Figures A and B after a motor vehicle collision. After debridement and external fixation, he is taken to the operating room for definitive soft tissue flap coverage and intramedullary nailing. Administration of recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) at the time of fracture fixation will lead to which of the following
Administration of rhBMP-2 at the time of definitive fixation has been shown to decrease the need for subsequent bone grafting procedures in Gustilo-Anderson type IIIA and IIIB open tibia fractures.
Swiontkowski et al performed a subgroup analysis of two prospective randomized control studies regarding the use of rhBMP-2 in open tibia fractures. The authors found a significant risk reduction in the need for secondary procedures, including bone grafting, with the addition of rhBMP-2 for type IIIA and IIIB open tibia fractures.
Govender et al performed a randomized prospective RCT of 450 patients with open tibia fractures allocated to tibia nailing or nailing with one of 2 different dosages of rhBMP-2. They found a 44% reduction in the need for secondary intervention as a result of delayed union, better wound healing, and decreased infection in the higher dose rhBMP-2 group compared to controls.
Splitting between the iliotibial band and biceps tendon, then retracting the gastrocnemius posteriorly provides exposure for which of the following procedures?
The posterior-lateral capsular exposure needed to protect the neurovascular structures and allow suturing for an inside-out lateral meniscal repair is performed by developing the interval between the iliotibial band and biceps tendon. The lateral gastrocnemius is then retracted posteriorly and medially where it helps protect the neurovascular structures. Splitting below the biceps tendon puts the peroneal nerve at risk.
According to Turman & Diduch, the gold standard remains inside-out vertical mattress suture repairs. They stated that all-inside repairs are best reserved for special circumstances, such as in the setting of concurrent ACL reconstruction.
when to go anterior on cervical myelopathy
> 10 degrees kyphosis, if >3 levels then have to back up with posterior fixation
symptom of C2 compression
occipital headache
When to do surgery for ADI and PADI
ADI >10 or PADI <14
Type of collagen for annulus and nucleus pulposis
Annulus - type 1
NP - type 2
What does obturator oblique view show
anterior column, posterior wall
Spurr sign on what image and what does it mean
both column tab fx
Seen on obturator oblique xray
when to do surgery on posterior wall fx
> 40% or if smaller and unstable
most common complication after ORIF fem neck in young person
osteonecrosis
BMPs work on what proteins
SMAD
BMPs are osteoinductive or conductive
osteoinductive - generates d novo bone formation.
EXCEPT BMP 1 and 3 are not osteoinductive
Achondroplasia occurs in what zone
zone of proliferation
Ewings translocation and marker
11:22 translocation, CD99 marker (3x33)
What happens if you have excess SHH or too little
postaxial polydactyly - too much
Postaxial hypoplasia - too little
Tibial bowing (AL/AM/PM) associated with
Anterolateral - always look for NF
Anteromedial - always missing - hemimelia
Posteromedial - probably mild - resolves
what happens when bone isn’t loaded
sclerostin increases which leads to decreased bone mass, also dickhofff is made which decreases bone mass as well
what cell line do osteoclasts come from
hematopoietic
discuss important enzymes in osteoclast function
Carbonic anhydrase - makes acid
Cathepsin K - dissolves collagen type 1 (main col in bone)
