Failure of differentiation (Swanson type 2) in the proximal aspect of the forearm
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Inheritance of radioulnar synostoses?
Usually sporadic but Familial cases with Autosomal dominance
RARE, bilateral in 60%
Associated with syndromes - apert, arthrogryposis, klinefelter's syndrome
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Clinical features of radioulnar synostosis?
Spectrum of fixed and limited pronation/ supination
Look at other associated syndromes
Other joints for arthrogryposis,
Klinefelter syndrome (XXY) - male with extra X chromosome.
Features of female - large breasts, small penis, less hair
Apert syndrome - microcephaly
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Why is the arm commonly fixed in pronation?
Limb bud in UL starts in pronation and progress to supination
This is opposite from the LL which stays in pronation
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Classification of radioulnar synostosis?
Cleary and Omar- Based on fibrous vs bony, location
Type 1 = Fibrous
2 = Bony
3 = Bony + posterior dislocation of radius
4 = Bony + anterior dislocation of radius
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Management of radioulnar synostosis?
Usually conservative management as the shoulder is able to compensate sufficiently
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What are the 2 broad options of management?
1. Mobilization Surgery/ Excision and interposition - poor outcomes with nearly 100% recurrence
2. Corrective osteotomy at mid ulnar shaft and distal radius and fuse at 10 Β° supination
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How do you do osteotomy surgery for radioulnar synostosis?
Goal = Osteotomy to fix forearm in more functional position
Ramachandran et al. JBJS 2005 case series of 6 forearms. Mean 68 Β° pronation, corrected to 10 Β° supination
Osteotomy done at mid ulnar shaft with retrograde flexible nail inserted via olecranon (only one nail); Radial osteotomy at the distal diaphyseal-metaphyseal junction through a volar approach
Arm supinated to 10 Β°. Above elbow cast applied with elbow flexed to 90 Β°.
Cast converted to below elbow at 3 weeks and wire removed. Below elbow cast for further 3 weeks
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What angle do we correct it to?
Controversial. Ramachandran et al. JBJS 2005 advocates 10 degrees supination in all cases, whether unilateral or bilateral. All patients were pleased with position