Evaluation of the ability of a person to move his or her shoulder with an upward arm movement could help demonstrate joint hypermobility associated with Ehlers-Danlos syndrome (EDS), a study suggests.
The study, “Gleno-humeral abduction measurement in patients with ehlers-danlos syndrome,” was published in the journal Orthopaedics & Traumatology: Surgery & Research.
EDS is a genetic condition that affects connective tissues such as bones, cartilage, and skin. Symptoms of EDS include abnormal walking or gait and posture, easy bruising, stretch marks, atrophic scars in the skin, and joint hypermobility.
In fact, “loose” joints — assessed by the Beighton hypermobility score — is one of the most informative aspects of a physical exam. However, this evaluation can be affected by many external factors, namely the current pain level, patient cooperation, and joint stiffening due to age.
There is a need to find a joint-mobility parameter that is not affected by age, and that is reliable and easy to use.
David Cypel, from the Hôtel-Dieu Teaching Hospital in Paris, believes that evaluating the shoulder joint during arm movement, called gleno-humeral abduction, might help more accurately diagnose joint hypermobility in EDS.
To explore this hypothesis, he conducted a retrospective case-control study with 110 patients diagnosed with EDS, and 100 individuals used as controls. The EDS patient group included 87 women (mean age of 32.5 years) and 23 males (mean age of 22 years). The control group included 50 females, with a mean age of 50, and 50 males, with a mean age of 45.
Standard tests were performed systematically to measure the abduction range.
Overall, the 110 EDS patients had a mean Beighton score of five out of a maximum of nine points. Only four patients showed a normal range of gleno-humeral abduction, considered to be about 90 degrees; the remaining 106 patients had higher registered angles, with a mean of 116 degrees. The proposed test was found to have a sensitivity of 96.4% for EDS detection.
“The mean value in the [EDS] cases was 29% higher than the normal value,” Cypel wrote.
In particular, average gleno-humeral abduction measure for patients between the ages of 6 and 40 years was 118.6 degrees, while for patients older than 40, this mean value was 110.6 degrees. Respectively, mean Beighton scores for these two age groups were 6.6 and 4.55.
Compared with the control group, where 15 of 200 tests had an unexpectedly higher range of gleno-humeral abduction, Cypel estimates that this test has a 92.5% specificity for detecting EDS cases.
Four abduction measurements were performed by five students besides the principal researcher, and they found only a small difference of 1.4 degrees, which indicates good inter-examiner reproducibility.
“In patients whose medical history suggests EDS, gleno-humeral abduction measurement may thus provide proof of joint hypermobility, even when the Beighton score is less than 5, as was the case in 45 (41%) of our patients,” Cypel concluded.