Although the skin may present most problems in patients with Ehlers-Danlos Syndrome, symptoms may also result from the musculoskeletal system. The abnormal protein that contributes to the structure of the skin and blood vessels also contributes to the structure of the joints. Patients may find that joints dislocate spontaneously. Only a minority of patients have dislocations of the hips. The joints may dislocate following the most minor of trauma or even in the apparent absence of trauma, for example, on rolling over in bed.
Reduction is usually easy and often patients learn to reduce the joints themselves.
The degree of hyperlaxity and frequency of dislocation usually diminish as the patient gets older though, probably because of circulating maternal hormones, joints may be more susceptible to dislocation during pregnancy. Repeated minor trauma to unstable joints can cause effusions to form in the joints. Joints are normally lubricated by a small amount of synovial fluid. In an effusion this increases, probably as a protective reaction. As a result the joint may feel tense and become swollen.