Congenital Dislocation Of Shoulder
It is one of the congenital anomalies of the shoulder where the dislocation of shoulder present at birth. It is of three types
- True congenital dislocation, developing in utero [Extremely rare]
- Dislocation caused directly by trauma at birth
- Acquired dislocation developing secondary to a brachial plexus injury. It is the most common type
Etiology of Congenital Dislocation of Shoulder
In utero maldevelopment is the major cause for true congenital dislocations of the shoulder. This usually occurs due to bony abnormalities of the shoulder girdle.
The bony abnormality can be hypoplasia of the scapula or glenoid dysplasia.
Xrays can detect and differentiate congenital dislocation of the shoulder from upper humeral fractures.
CT and MRI are much more sensitive in the diagnosis than radiographs and should be used when in doubt.
When functional impairment is minimal, no treatment is indicated because there is a possibility of further decreasing functional use of the limb.
Operative procedures employed depend on the individual case.
Where indicated, early reduction and containment of the humeral head in the glenoid socket might help achieve a satisfactory long-term outcome. Open reduction may be required for release of contractures.
In severe aplastic malformations, surgical measures are often futile because the function cannot be improved.
Congenital Glenoid Hypoplasia
This malformation is due to failure of formation of the lower and upper glenoid epiphysis. It is characterized in the radiogram by flattening, shallowness, and an underdeveloped appearance of the glenoid cavity.
The lower aspect of the clavicle may be hypertrophied into a bony prominence, and there may be spina bifida in the cervical region.
Often, the abnormality is bilateral and is encountered as an isolated malformation. It may be hereditary. Samilson reported congenital glenoid hypoplasia in three successive generations of the same family.
Occasionally, it is seen in association with other congenital malformations such as Apert’s syndrome, Hurler’s syndrome, aglossia-adactylia, oculodento-osseous dysplasia, Holt-Oram syndrome, and Cornelia De Lange’s syndrome.
Clinically, in the young child, the anomaly is usually asymptomatic and may be found incidentally in the radiogram. In the older patients, however, the glenohumeral joint may be unstable and may become dislocated posteriorly.
The range of abduction of the shoulder will be restricted, and occasionally it may cause neurovascular embarrassment. In the differential diagnosis, one should consider glenoid hypoplasia secondary to obstetrical brachial plexus palsy or multiple epiphyseal dysplasias.
Management should be individualized. Often no treatment is indicated.
In symptomatic posterior dislocation of the shoulder, glenoidplasty with a bone graft may help.
Aplasia of Scapula
Congenital absence of the scapula is extremely rare. It is usually associated with ipsilateral Amelia. Treatment consists of fitting with an upper limb prosthesis.
Torsional Deformity of Glenoid Cavity
This deformity will cause posterior or anterior dislocation of the shoulder and can be demonstrated on an axillary radiogram or a computed tomographic torsion study of the glenoid cavity.
Treatment consists of osteotomy of the neck of the scapula and insertion of a wedge bone graft to correct the abnormal glenoid torsion.
Congenital Varus Deformity of Proximal Humerus
This malformation may be developmental or secondary to neurofibromatosis or rachitic syndromes.
Torsional Deformity of Humeral Neck
Excessive retroversion will cause posterior dislocation of the glenohumeral joint, and excessive anteversion will cause anterior dislocation. Computed axial tomography will show the degree of humeral torsion. When torsion deformity is severe and is causing shoulder joint instability, it is treated by derotation osteotomy.