Connective Tissue Disorders

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

Down syndrome

  • Musculoskeletal manifestations of Trisomy 21 include short stature and joint laxity with possible recurrent dislocation (especially patella) which may require stabilization
  • Atlanto‐axial instability in the c‐spine can also occur