MCQs – Congenital 1

Modern Study Review (AI-Generated)

High-Yield Summary

This topic is a staple of the Royal College exam, focusing heavily on congenital upper limb deformities, skeletal dysplasias, and collagen disorders. The single most important clinical decision often hinges on the presence or absence of key anatomical structures (e.g., radius in radial club hand) or the timing of intervention (e.g., excision of radial head dislocation after skeletal maturity). While classic teaching emphasizes non-resection of congenital radioulnar synostosis due to irreversible loss of motion, modern practice increasingly favors osteotomy for functional positioning. Understanding inheritance patterns and associated systemic features is critical for comprehensive management and genetic counseling.

High-Yield Decision Matrix

Active Recall Q&A

Radial Club Hand

Q: What percentage of radial club hand cases are bilateral?
A: At least 50% of radial club hand cases are bilateral.
Related Pearl: Bilaterality suggests a systemic developmental defect, important for genetic counseling and screening for associated syndromes.

Q: What thumb abnormality is associated with complete absence of the radius in radial club hand?
A: Thumb deficiency is associated if the entire radius is absent.
Related Pearl: Severity of thumb hypoplasia correlates with radial deficiency, influencing reconstructive options and functional prognosis.

Q: Which nerve is most endangered during surgical approach to radial club hand?
A: The median nerve is the most endangered structure.
Related Pearl: Meticulous dissection is essential to avoid median nerve injury, which can severely impair hand function.

Q: Is radial club hand associated with proximal intercalary defects of the arm?
A: No, the humerus may be short but there is no proximal intercalary defect.
Related Pearl: Differentiates radial club hand from other limb deficiencies involving segmental bone loss, guiding diagnosis.

Q: What is the most common type of radial club hand?
A: Type IV, characterized by absent radius.
Related Pearl: Classification guides prognosis and surgical planning; Type IV is the most severe form.

Congenital Radioulnar Synostosis

Q: Where does congenital radioulnar synostosis usually occur?
A: In the proximal forearm, usually the proximal third.
Related Pearl: Proximal location severely limits forearm rotation, impacting functional positioning.

Q: Does resection of the synostosis restore forearm motion in congenital radioulnar synostosis?
A: No, resection never restores motion and is not recommended.
Related Pearl: Osteotomy to improve forearm position is preferred; resection risks complications without functional gain.

Q: What is the gender predilection for congenital radioulnar synostosis?
A: Males are more commonly affected than females.
Related Pearl: Awareness of male predominance aids clinical suspicion and diagnosis.

Q: What is the typical forearm position in congenital radioulnar synostosis?
A: The forearm is usually pronated.
Related Pearl: Fixed pronation deformity affects activities of daily living and may require corrective osteotomy.

Q: Is congenital radioulnar synostosis usually unilateral or bilateral?
A: It is often bilateral.
Related Pearl: Bilaterality supports a developmental anomaly rather than isolated trauma.

Congenital Radial Head Dislocation

Q: How does congenital radial head dislocation typically present?
A: It may be asymptomatic and discovered incidentally after trauma.
Related Pearl: Asymptomatic cases do not require intervention; misdiagnosis can lead to unnecessary surgery.

Q: Should congenital radial head dislocation be reduced?
A: No, it should not be reduced; excision is reserved for symptomatic cases after skeletal maturity.
Related Pearl: Early reduction attempts can damage growth plates and worsen outcomes.

Thumb Deformity

Q: What does a thumb deformity passively correctable with MCP flexion and IP extension suggest?
A: Possible congenital deficiency of the extensor pollicis brevis (EPB).
Related Pearl: EPB deficiency alters thumb extension mechanics, influencing reconstructive strategy.

Nail-Patella Syndrome

Q: What is nail-patella syndrome?
A: Onycho-osteodystrophy with absent/hypoplastic patellas, elbow abnormalities, iliac horns, and dysplastic nails.
Related Pearl: Multisystem involvement requires interdisciplinary management including orthopaedics and genetics.

Q: What is the inheritance pattern of nail-patella syndrome?
A: Autosomal dominant.
Related Pearl: Family screening is important due to dominant transmission.

Q: What are the key clinical features of nail-patella syndrome?
A: Hypoplastic or absent patella (often subluxed), knee valgus and flexion deformity, iliac horns, hypoplastic or absent nails, and radial head abnormalities.
Related Pearl: Radiographic iliac horns are pathognomonic and aid diagnosis.

Tibial Hemimelia

Q: What determines the choice between Symes amputation and knee disarticulation in tibial hemimelia?
A: Symes amputation is considered if the tibia is adequate; knee disarticulation if the tibia is atrophic.
Related Pearl: Preserving the knee joint improves prosthetic function and mobility.

Fibular Hemimelia

Q: What are the associated deformities in fibular hemimelia?
A: Femur may be short; tibia is shortened and anteromedially bowed; foot is in valgus.
Related Pearl: Severity of fibular deficiency correlates with tibial shortening and foot deformity.

Arthrogryposis

Q: What are the causes of arthrogryposis?
A: Neuropathic problems, myopathic problems, and decreased intrauterine space.
Related Pearl: Early diagnosis and therapy improve joint mobility and function.

Klippel Feil Syndrome

Q: Which neck fusion pattern in Klippel Feil syndrome most likely requires surgery?
A: Occipitalization of C1 plus C2-3 fusion, or two long cervical fusions with a normal segment in between.
Related Pearl: These patterns cause significant instability or neurological compromise.

Q: What are common clinical features of Klippel Feil syndrome?
A: Shoulder stiffness (with Sprengel’s deformity), decreased neck range of motion, synkinesis, and facial nerve palsies without gaze palsy.
Related Pearl: Synkinesis is a unique movement disorder important for clinical recognition.

Achondroplasia

Q: Why is the foramen magnum small and compressed in achondroplasia?
A: Because the foramen magnum is formed by endochondral ossification, which is affected in achondroplasia.
Related Pearl: Foramen magnum stenosis can cause neurological symptoms requiring decompression.

Q: What is the pathophysiology of achondroplasia?
A: Failure of calcification of the chondroid matrix and failure of cartilage cell proliferation in the physis.
Related Pearl: This leads to characteristic short-limb dwarfism and skeletal abnormalities.

Q: What is the inheritance pattern of achondroplasia?
A: Autosomal dominant.
Related Pearl: Most cases are sporadic mutations, but familial cases follow dominant inheritance.

Q: Which limb bones are more involved in achondroplasia, and what deformity results?
A: Radial and tibial involvement is greater than ulnar and fibular; fibular overgrowth causes genu varum.
Related Pearl: Asymmetric growth plate involvement explains characteristic limb deformities.

Osteogenesis Imperfecta

Q: What is the best surgical treatment for large angular tibial deformities in osteogenesis imperfecta?
A: Multiple osteotomies with intramedullary fixation after bracing fails.
Related Pearl: Early surgical intervention prevents fractures and improves limb alignment.

Q: What is the main defect in osteogenesis imperfecta?
A: Defect in collagen maturation.
Related Pearl: Collagen defects lead to bone fragility and recurrent fractures.

Collagen Disorders

Q: Which diseases are related to collagen disorders?
A: Ehlers-Danlos syndrome, osteogenesis imperfecta, Marfan’s syndrome, and Peyronie’s disease.
Related Pearl: Collagen abnormalities affect connective tissue integrity across multiple systems.

Q: Is osteopetrosis a collagen disorder?
A: No, osteopetrosis is not related to collagen disorders.
Related Pearl: Osteopetrosis is a bone remodeling disorder caused by osteoclast dysfunction, distinct from collagenopathies.

Classic Clinical Notes

• Radial club hand is associated with thrombocytopenia, bilaterality in at least 50%, associated thumb deficiency if the entire radius is absent, a short humerus.

• The most endangered structure when doing a surgical approach to the radial clubhand is the median nerve – BEWARE!

• Radial club hand is not associated with a proximal intercalary arm defect – the humerus may be short, but it is not an intercalary defect.

• The most common type of radial clubhand is the type IV – absent radius.

• Congenital radioulnar synostosis usually occurs in the proximal forearm.

• For the congenital radioulnar synostosis, resection of the synostosis never restores motion – do not do this operation. If anything, you can osteotomize them to position their hand in better position, but you will not restore motion. Basically, they are stuck with a one bone forearm.

• For congenital radioulnar synostosis, males are more affected than females, the synostosis is usually in the proximal third, the forearm is usually pronated, and the disorder is often bilateral.

• For congenital radial head dislocation, it may be asymptomatic and be brought to your attention by some other incidental trauma. Look at the shape of the head to give you an idea of if it has been out for some time. It should NOT be reduced – it should be excised if symptomatic but one should wait until the patient is skeletally mature.

• Thumb deformity that is passively correctable with MCP flexion, IP extension – ??? congenital deficiency of EPB?

• Nail-patella syndrome – onycho-osteodystrophy.

• Includes absent or hypoplastic patellas, elbow abnormalities, iliac horns, and dysplastic nails.

• Transmitted as a dominant trait.

• Get hypoplastic or absent patella that is subluxed, knee valgus and flexion deformity, iliac horns, nails hypoplastic or absent, radial head abnormalities.

• For tibial hemimelia, if the tibia is pretty good, you can consider Symes. If it is atrophic, better off with knee disarticulation.

• For fibular hemimelia, the femur may be abit short as well. The tibia is shortened (the greater the fibular deficiency, the greater the shortening of the tibia) and anteromedially bowed. The foot is in valgus.

• Arthrogryposis is caused by many things: neuropathic problem, myopathic problem, and decreased interuterine space.

• For Klippel Feil, the combination of neck fusion most likely to require surgery is occipitalization of C1 and C2-3 fusion, or two long cervical fusions with a normal segment in between.

• Klippel Feil patients get shoulder stiffness (associated Sprengel’s deformity), decreased range of motion of the neck, synkinesis (an associated movement disorder) where an involuntary movement accompanies a voluntary movement. They also get facial nerve palsies, but not gaze palsy.

• The foramen magnum in achondroplastics is compressed and small – although the head is formed by intramembranous bone formation, the foramen is endochondral, and thus affected.

• The pathology behind achondroplasia is failure of calcification of the chondroid matrix and failure of cartilage cell proliferation in the physis.

• The main inheritance pattern of achondroplasia is autosomal dominant.

• In achondroplastics, the ulnar and fibular involvement is less than the radial (radial head) and tibial (genu varum) involvement. The fact that the ulnar and fibular growth plates are less involved leads to the genu varum secondary to fibular overgrowth.

• For the osteogenesis imperfecta kid with huge angular deformities of the tibia, best to do multiple osteotomies with IM fixation. Initially, you would like to brace, but when the deformity gets to be too big to brace, then you might as well do the osteotomies before the thing breaks.

• Ehlers Danlos, osteogenesis imperfecta, Marfan’s syndrome, and peyronies disease are all related to collagen disorders. Osteopetrosis is not.

• In osteogenesis imperfecta, the main defect is in collagen maturation.

Last Updated on January 25, 2026 by Christian Veillette