Due to genetic disorders of collagen synthesis, mainly type I - found in bone, tendon and ligaments
Pathophysiology
Results in joint hypermobility
Affect soft tissues more than bone (vs osteogenesis imperfecta which predominantly affects type I collagen of bone)
Generalised (familial) joint laxity
Around 5% of normal people have hypermobility of the joints which usually runs in families and is inherited in a dominant manner
Patients may describe themselves as 'double‐jointed' and be able to perform tricks as a party piece (eg voluntary dislocation of the shoulder)
People with generalized ligamentous laxity are more prone to soft tissue injuries (ankle sprains) and recurrent dislocations of joints (especially shoulder and patella) which may be painful
Marfan's syndrome
Autosomal dominant or sporadic mutation resulting in tall stature with disproportionately long limbs and ligamentous laxity
Associated features include a high arched palate, scoiliosis, flattening of the chest (pectus excavatum), eye problems (lens dislocation, retinal detachment), aortic aneurysm and cardiac valve incompetence
Cardiac abnormalities may result in premature death (aneurysm, dissection, valvular disease)
Patients rarely require orthopaedic surgery and soft tissue stabilization of dislocating joints usually has disappointing results as the biological abnormality cannot be corrected
Ehlers-Danlos syndrome
Heterogeneous condition which is often autosomal dominantly inherited with abnormal elastin and collagen formation
More than 10 types have been described
Clinical features include profound joint hypermobility, vascular fragility with ease of bruising, joint instability and scoliosis
Bony surgery may be required for dislocating joints however bleeding can be a problem and skin healing can be poor with stretched scars or wound dehiscence common
Musculoskeletal manifestations of Trisomy 21 include short stature and joint laxity with possible recurrent dislocation (especially patella) which may require stabilization