Full Question & Answer Text (for Search Engines)
Question 1:
The Ponseti method of clubfoot cast treatment starts with which of the following steps:
Options:
- Pronation of the forefoot
- Dorsiflexion of the first ray
- Dorsiflexion of the ankle
- External rotation of the foot
- Internal rotation of the foot
Correct Answer: Dorsiflexion of the first ray
Explanation:
Dorsiflexion of the first ray is the first step in the Ponseti method of cast treatment. Dorsiflexion decreases the cavus component. Pronation of the forefoot is the opposite of dorsiflexion and produces the opposite desired motion. Dorsiflexion of the ankle should be performed after the Achilles tenotomy. External rotation of the foot is performed later. Internal rotation of the clubfoot is never done.
Question 2:
When correcting a clubfoot by the Ponseti method, the lateral mold on the foot must be placed against which of the following structures:
Options:
- The head of the talus
- The calcaneus
- The cuboid
- The fifth metatarsal
- The tibia
Correct Answer: The head of the talus
Explanation:
Ponseti describes rotating the clubfoot against the head of the talus to allow the lateral side of the foot (calcaneus and cuboid) to rotate laterally.
Question 3:
Which of the following molecules is defective in osteogenesis imperfecta:
Options:
- Type I collagen
- Type II collagen
- C alcium transport channels
- Vitamin D 1,25-dihydroxylase
- Renal tubular reabsorption of phosphate
Correct Answer: Type I collagen
Explanation:
Osteogenesis imperfecta (OI) is a disorder of type I collagen. Numerous different mutations in the genes for this molecule have been described, accounting for the variable clinical phenotypes. Type II collagen is important for articular cartilage, but it is not implicated in the pathogenesis of OI. The other factors are not abnormal in OI.
Question 4:
Regulation of proximal-to-distal development of the limbs is determined by which of the following:
Options:
- Fibroblast growth factor gene
- Homeobox genes
- Platelet-derived growth factor gene
- Leptin gene
- Sulfate transport gene
Correct Answer: Homeobox genes
Explanation:
Proximal-to-distal development of the limbs in utero is determined by the homeobox genes. These genes are located on a number of different chromosomes (2, 7, 12, and 17), and they guide the proximal-to-distal organization of limb and digital development.
Question 5:
Meryon sign refers to which of the following physical phenomena in patients with muscular dystrophies:
Options:
- Wide-based gait
- Use of upper extremities in coming to stand
- Tendency to â slip throughâ when patient is suspended under the axillae
- Absence of facial expression
- Inability to fully flex the neck
Correct Answer: Tendency to â slip throughâ when patient is suspended under the axillae
Explanation:
Meryon sign is the weakness of shoulder adduction when a child is lifted or suspended under the axillae. The examiner will feel that the child is slipping through his or her hands. It is due to weakness of the shoulder girdle muscles. Meryon sign is present in limb-girdle dystrophies and fascioscapulohumeral dystrophy.
Question 6:
Spinal muscular atrophy is best characterized as which of the following:
Options:
- An upper motor neuropathy
- A lower motor neuropathy
- A sensory neuropathy
- A peripheral neuropathy
- A generalized myopathy
Correct Answer: A lower motor neuropathy
Explanation:
Spinal muscular atrophy is a degeneration of the anterior horn cells of the spinal cord. It results in a nonprogressive lower motor neuron disease with preservation of sensation and intelligence. There is no spasticity or hyperreflexia.
Question 7:
Which of the following is the gene that is abnormal in spinal muscular atrophy:
Options:
- Survival motor neuron genes 1 and 2
- Gene for dystrophin
- Gene for frataxin
- Gene for peripheral myelin protein
- Gene for emerin
Correct Answer: Survival motor neuron genes 1 and 2
Explanation:
Spinal muscular atrophy is a disorder of survival motor neuron genes 1 and 2; its product is not yet known. Dystrophin is abnormal in Duchenne and Becker muscular dystrophy. Frataxin is abnormal in Friedreich ataxia. Peripheral myelin protein is defective in C harcot-Marie-Tooth disease. Emerin is abnormal in Emery-Dreifuss syndrome.
Question 8:
Emery-Dreifuss syndrome is manifest by all of the following except:
Options:
- Heel cord contractures
- Elbow contractures
- Limited cervical flexion
- Scoliosis
- C ardiomyopathy
Correct Answer: Scoliosis
Explanation:
Emery-Dreifuss syndrome is due to an encoding error in emerin, which may be a stabilizer of the nuclear membrane. Emery- Dreifuss syndrome is characterized by a triad of contractures of the heel cord, elbow, and cervical spine. Cardiomyopathy may cause heart block or other arrhytmias. Scoliosis is not commonly found in this condition.
Question 9:
Which of the following bones of the foot is normally ossified at birth:
Options:
- C uboid
- First cuneiform
- Third cuneiform
- Navicular
- First metatarsal
Correct Answer: First metatarsal
Explanation:
The metatarsals are ossified at birth, along with the talus and the calcaneus. The cuboid ossifies at 1 month, followed by the third, second, and first cuneiforms. The navicular does not ossify until age 2 or 3 years. These facts are useful when interpreting radiographs for congenital foot deformities such as clubfoot. The location of the navicular must often be inferred from the position of the first metatarsal.
Question 10:
C hronic recurrent multifocal osteomyelitis is caused by which of the following:
Options:
- Staphylococcus epidermidis
- Corynebacterium
- Spirochetal infection
- Viral infection
- No organism has been isolated
Correct Answer: No organism has been isolated
Explanation:
Chronic recurrent multifocal osteomyelitis presents as chronic joint pain at multiple locations and at different times. No organism has been isolated from patients presenting with chronic recurrent multifocal osteomyelitis. There is no role for surgery or antibiotics because symptoms generally resolve over a period of time.
Question 11:
A 5-year-old boy has midfoot pain and limps at the end of long walks. Radiographs show sclerosis and fragmentation of the navicular on the involved side. Recommended treatment is:
Options:
- C ore decompression
- Activity modification
- Electrical stimulation
- Bone grafting of the ossific nucleus of the navicular
- Talonaviculocuneiform fusion
Correct Answer: Activity modification
Explanation:
Kohler s disease, or avascular necrosis of the tarsal navicular, occurs spontaneously. It is more common in boys than girls, and it frequently presents before the age of 8 years. C onservative treatment consisting of counseling and activity modification is usually sufficient, with reossification ensuing. Occasionally cast immobilization seems helpful in allaying symptoms.
Question 12:
An 11-year-old girl presents with pain in the area of the second metatarsophalangeal joint. Pain is increased with joint motion. Radiographs show increased density and flattening of the metatarsal head. Recommended treatment is:
Options:
- Core decompression
- Decreased activity and use of orthotics
- Bone graft of the epiphysis of the second metatarsal
- Fusion of the metatarsophalangeal joint in a functional position
- Osteotomy of the second metatarsal neck
Correct Answer: Decreased activity and use of orthotics
Explanation:
Freibergs disorder, or osteochondrosis of the second metatarsal head, is most common in teenage girls, especially dancers. The length of this metatarsal may be a factor in the pathogenesis. Treatment must be conservative in most cases, although a mild degree of symptoms may persist if epiphyseal flattening does not remodel.
Question 13:
Which of the following complications is not a recognized risk of the Salter osteotomy:
Options:
- Recurrent subluxation
- Pin migration
- Pin infection
- Avascular necrosis
- Migration of the bone graft
Correct Answer: Avascular necrosis
Explanation:
Avascular necrosis is not a risk of the osteotomy, but rather of an open or closed reduction that may sometimes accompany it. All of the other complications are accepted as possible, although rare, sequelae of the procedure.
Question 14:
The result of treatment of developmental dysplasia of the hip with Salter osteotomy is is worse with which of the following:
Options:
- A higher degree of the dislocation before treatment (Tonnis grade)
- Bilaterality
- Higher preoperative acetabular index
- Increased age at surgery
- Performing open reduction at a separate surgery than the osteotomy
Correct Answer: A higher degree of the dislocation before treatment (Tonnis grade)
Explanation:
Salter osteotomy is effective in treating developmental dysplasia of the hip in young children. The result is worse with higher degrees of dislocation as assessed by the Tonnis system. It is better if the open reduction (if needed) is performed as a separate step than the osteotomy. The other factors have not been shown to be predictive.
Question 15:
A 4-year-old girl with developmental hip dysplasia is advised to have a Salter innominate osteotomy. When the family asks about the long-term survivorship of the reconstruction, the surgeon tells them that good 30-year follow-up results are likely in at least what percentage of patients:
Options:
Correct Answer: 85%
Explanation:
Thirty-year survivorship analysis shows good to excellent results in at least 85% of patients.
Question 16:
Which of the following statements best describes the effect of leptin on the skeleton:
Options:
- Leptin increases bone formation.
- Leptin increases muscle mass.
- Leptin decreases bone formation.
- Leptin decreases muscle mass.
- Leptin increases longitudinal growth.
Correct Answer: Leptin decreases bone formation.
Explanation:
Leptin is a polypeptide secreted by adipocytes and acts upon the hypothalamus as a powerful inhibitor of bone mass.
Question 17:
Which of the following organisms is the most common cause of obturator internus muscle abscess in children:
Options:
- Streptococcus A
- Staphylococcus aureus
- Salmonella
- Escherichia coli
- Pseudomonas aeruginosa
Correct Answer: Staphylococcus aureus
Explanation:
Abscess of the obturator internus muscle may mimic septic arthritis. It is best diagnosed by magnetic resonance image. <1>Staphylococcus aureus is the most common causative organism, accounting for 75% of cases of obturator internus muscle abscess. Antibiotic treatment should be tried first and is successful in most cases.
Question 18:
Which of the following studies is likely to help in distinguishing osteomyelitis from infarct in a patient with sickle cell anemia:
Options:
- Magnetic resonance imaging
- C omputed tomography
- Bone and bone marrow scans
- Ultrasound
- Plain radiographs
Correct Answer: Bone and bone marrow scans
Explanation:
The combination of bone and bone marrow scan is the only imaging method that is useful in distinguishing osteomyelitis from infarct in patients with sickle cell anemia. The bone marrow scan is normal, but the bone scan shows increased uptake in a patient with osteomyelitis.
Question 19:
A 10-year-old boy with diplegic cerebral palsy walks with his knees turned in significantly. He has the appearance of severe valgus when walking. When examined in a supine position, there is no excessive valgus of the knees. His popliteal angle is 45°. An Ely test is negative. His hip internal rotation in the prone position is 80°, while his external rotation is 15°. The surgeon wishes to improve the patientâ s knee position during gait. The intervention most likely to accomplish this is:
Options:
- Botulinum toxin injection to the hamstrings
- Hamstring lengthening, medially
- Hamstring lengthening, medially and laterally
- Rectus transfer into the biceps
- Femoral derotation osteotomy
Correct Answer: Femoral derotation osteotomy
Explanation:
The findings highlighted here are those of severe anteversion. Anteversion causes the appearance of valgus of the knees, and it does not resolve spontaneously in cerebral palsy. The procedure most likely to make a lasting improvement in the patient is derotational osteotomy of the femur.
Question 20:
Which of the following procedures is most likely to increase recurvatum of the knee in patients with diplegic cerebral palsy:
Options:
- Medial hamstring lengthening
- Medial and lateral hamstring lengthening
- Rectus transfer to the hamstrings
- Tendoachilles lengthening
- Adductor lengthening
Correct Answer: Medial and lateral hamstring lengthening
Explanation:
Lengthening of the medial and lateral hamstrings is more likely to overlengthen the posterior knee checkrein. Therefore, it should only be performed in selected cases with severe spasticity and no cospasticity of the rectus femoris. Lengthening of only the medial hamstrings carries less risk. The other procedures listed do not carry this risk.
