Orthopedics: AIIMS NOV 2014

Q-1. Bone dysplasia is invariable seen in
a) Hyperparathyroidism
b) Osteosarcoma
c) Developmental defect
d) Osteomalacia

Answer: Developmental defect
Explanation:
The osteochondro-dysplasias, or skeletal dysplasias are a genetically heterogeneous group of distinct disorders, and many of them can present in the prenatal period as demonstrated by ultrasound.
The skeletal dysplasias can be inherited as autosomal dominant, autosomal recessive, or X-linked disorders, and some disorders that result from imprinting errors, somatic mosaicism, and teratogen exposure.
Skeletal dysplasias are characterized by abnormalities of cartilage and bone growth, resulting in abnormal shape and size of the skeleton and disproportion of the long bones, spine, and head.

Q-2. A 10 year child presented with a mid tibial swelling which on X-ray, revealed a lytic lesion with sclerotic margins. What is the most likely diagnosis?
a) Osteoid osteoma
b) Eosinophilic granuloma
c) Fibro-cortical defect
d) Fibrous dysplasia

Answer: Osteoid osteoma
Explanation:
Osteoid osteoma:
It is the commonest true benign tumor of the bone.
It consists of a nidus of tangled arrays of partially mineralized osteoid trabeculae surrounded by dense sclerotic bone.
Tumor is seen commonly between the ages of 5-25 years.
The bones of lower extremity are more commonly affected and tibia is commonest.
Tumor is located in diaphysis of the long bones.
X-Ray finding: A zone of sclerosis surrounding a radiolucent nidus

Q-3. A child is diagnosed with osteosarcoma based on Sunray appearance seen on X-ray. This is because of
a) Calcification along periosteum
b) Calcification along the blood vessels
c) Periosteal reaction
d) Soft tissue invasion

Answer: Calcification along the blood vessels
Explanation:
Osteosarcoma is the second most common and a highly malignant primary bone tumor.
All osteo-sarcomas are aggressive lesions and metastasize widely through the blood stream, usually first to the lungs.
Common sites of origin: Lower end of femur> Upper end of tibia> Upper end of humerus
Codman’s triangle: A triangular area of sub-periosteal new bone is seen at the tumor-host cortex junction at the ends of the tumor.
Sun Ray appearance: As the periosteum is unable to contain the tumor, tumor grows into the overlying soft tissues. Now bone is laid down along the blood vessels within the tumor growing centrifugally, giving rise to a sun ray appearance on the X-Ray.

Q-4. Which of the following displacement is not seen in Colles fracture?
a) Dorsal displacement
b) Supination
c) Volar tilt
d) Radial tilt

Answer: Volar tilt
Explanation:
Displacement in Colles fracture:
Impaction of fragments
Dorsal displacement
Lateral displacement
Dorsal tilt
Lateral tilt
Supination

Q-5. A person is hemiplegic and bed ridden for one year. Changes in bone mineral density are first seen in
a) Distal radius
b) Lumbar spine
c) Proximal femur
d) Proximal humerus

Answer: Proximal humerus
Explanation:
Physical inactivity contributes to accelerated bone loss after stroke, leading to heightened fracture risk
Osteoporosis leads to fracture of proximal humerus, proximal tibia, femoral neck and pelvis.
Weight-bearing exercise and avoidance of bed rest have the potential to prevent bone loss after stroke.

Q-6. A child is spinned around by his father holding his hand. Suddenly the child started crying and did not allow his father to touch his elbow. Which of the following is the likely diagnosis?
a) Supra-condylar fracture
b) Pulled elbow
c) Fracture olecranon process
d) Radial head dislocation

Answer: Pulled elbow
Explanation:
Pulled elbow:
Pulled elbow occurs in children between 2-5 years of age.
The head of radius is pulled partly out of the annular ligament when child a child lifted by the wrist.
The child starts crying and doesn’t allow touching his elbow.
Forearm lies in an attitude of pronation.

Q-7. A 40 year old female presents with multiple lytic bone lesions, fracture clavicle, periosteal resorption of 2nd and 3rd metatarsals. What is the most likely diagnosis?
a) Renal osteodystrophy
b) Osteomalacia
c) Hyperparathyroidism
d) Hyperthyroidism

Answer: Hyperparathyroidism
Explanation:
Hyperparathyroidism and bone disease:
Osteitis fibrosa cystica is skeletal manifestation of advanced primary hyperparathyroidism. Majority of hyperparathyroidism is the result of parathyroid adenoma.
Parathyroid hormone acts directly on the bone to release calcium into the extra-cellular fluid by stimulating calcium into the extra-cellular fluid by stimulating Osteoclastic resorption.
Parathyroid hormone > Activates adenyl cyclase> Formation of c-AMP> Increased synthesis of specific lysosomal enzymes> Break down the organic matrix of bone and release calcium
X-Ray findings of Osteitis fibrosa cystica:
Loss of lamina dura (The lamina dura surrounds the tooth socket and provides the attachment surface with which the Sharpey’s fibers of the periodontal ligament perforate.)
Sub-periosteal resorption of the phalanges (Tufting of phalanges) is a diagnostic feature of hyper-parathyroidism. It may be also occur at lateral end of the clavicle.
Important point:
The brown tumor is an expansile lytic lesion that arises due to excess osteoclast activity, such as hyperparathyroidism. It is generally affecting the maxilla/mandible.

Q-8. A 40 year old man presented with acute onset pain and swelling of left great toe. On X-ray, a punched out lytic lesion is seen on phalanx with sclerotic margins and overhanging bony edges. The likely diagnosis is
a) Gout
b) Rheumatoid arthritis
c) Psoriatic arthritis
d) Reiter’s syndrome

Answer: Gout
Explanation:
Gout:
Accumulation of sodium biurate crystals in some soft tissues such as cartilage, tendon and bursa
Patient usually beyond 40 years of age
MP joint of the big toe being a favorite site
Bursitis- Commonly of the olecranon bursa
Tophi formation deposit of uric acid salt in the soft tissue
X-Ray finding: A punched out lytic lesion with sclerotic margins and overhanging bony edges