The Orthopedic Strategy for Patients with Larsen syndrome
Authors: KAISSI ALI , Gubin Alexander , Ryabykh Sergey , Dougalis Vasileios , Al Kaissi Hamza , Kircher Susanne Gerit , Grill Franz 
Published: August 2024

.Background: Facial features are the first basic spring of medical knowledge in children and adults with congenital malformation. Children born with multiple contractures almost always receive the misdiagnosis of arthrogryposis multiplex. Larsen syndrome can easily be diagnosed at birth via the proper interpretations of its characteristic facial features and multiple dislocations. Instant diagnosis can facilitate the orthopaedic strategy for early treatment and follow-ups.

Material and Methods: Six children (four boys and two girls, age range from a few months to 7 year-old) have been referred to our departments for diagnosis and treatment. All children received their first misdiagnosis by the paediatricians as having arthrogryposis multiplex congenita . The clinical phenotype was our first decisive tool for diagnosis. All children exhibited the classical phenotype of Larsen syndrome, dish-like facies associated with multiple joint dislocations. Radiological phenotypic characteristics confirmed our clinical diagnosis. three children out of six showed unpleasant cervical spine deformities. The first child of a-2- year old became tetraplegic after minor trauma. One child presented with rigid cervical kyphosis . The third child wasa product of first related marriage and was born congenital tetraplegia . genotype has been carried out for confirmation .

Results: Three children underwent open reduction for congenital hip and knee dislocations. one child underwent spinal fusion CO-C7 because of tetraplegia. 3D reformatted and reconstruction CT scan of the craniocervical junction in two children showed unusual male segmentations along C2-3 causing effectively the development of rigid cervical kyphosis and one child with congenital tetraplegia showed serious malsegmentation of C1/C2 associated with hypoplasia of the anterior and the posterior rings of the atlas. These findings in the last two children made any surgical intervention quite sophisticated. Four of these children were compatible with the autosomal dominant type of Larsen syndrome and manifested heterozygous mutation in FLNB mapped 3p14.3, encoding and actin-binding protein, filamin B. One child showed no mutations in the FLNB, though his clinical and radiological phenotype and his family history of first related marriage were totally compatible within the diagnosis of autosomal recessive type of Larsen syndrome.

Conclusion: The orthopaedic strategy in patients with Larsen syndrome can not be achieved unless a precise diagnosis is has to be established as early as possible. Arthrogryposis multiplex congenita has been the first false diagnosis which was the reason for improper management.The most diagnostic confusion /error occurs to the paediatricians is the multiple contractures which are akin to arthrogryposis multiplex congenita. In practice, arthrogryposis multiplex congenita is a symptom complex rather than a precise diagnostic entity. The second diagnostic misconception is the generalized ligamentous hyperlaxity which can mimic hypotonia. Hypotonia in a newborn can be falsely categorized within the floppy infant syndrome. We used 3D reformatted CT scan to further understand the craniocervical junction pathology in three children with cervical spine kyphosis. Strikingly, mal segmentation and defective ossifications of the atlanto-axial spine segments in a child with Larsen syndrome and congenital tetraplegia