Sport pre-participation screening for asymptomatic atlanto-axial instability (AAI) in Down Syndrome (DS) patients

Down Syndrome (DS) is a clinical syndrome comprising of typical facial features and various physical and intellectual disabilities due to extra genetic material on chromosome 21, with one in every 1,000 babies born in the UK affected (1). DS patients are at risk of atlanto-axial instability (AAI) although AAI can occur in other conditions, such as rheumatoid arthritis, but this position statement deals specifically with DS patients and asymptomatic AAI.

AAI, also referred to as atlanto-axial subluxation, is defined as increased movement between the 1st (atlas) and 2nd (axial) cervical vertebra joint articulation, the atlantoaxial joint (2). AAI in DS patients is due to a combination of ligament laxity and bony abnormalities of the atlantoaxial joint. AAI is reported to occur in 6.8 – 27% of the DS population (3) (4) although this varies depending on the age of the patients which you are screening. Less than 1-2% (3) (5) of these patients are then thought to later develop symptomatic AAI although the natural history and progression of AAI is not well understood (2).

The risks associated with AAI are neurological injury from excessive movement of the cervical vertebra impinging on and then damaging the spinal cord although the risk of this during sporting activities is extremely rare (2) (6). Clearly physical activity and sports participation for DS patients has many biological, psychological and social benefits (7) and the Faculty of Sport and Exercise Medicine (FSEM), United Kingdom (UK) wish to promote safe physical activity and sport for all. The FSEM, UK has therefore produced a statement regarding sport pre-participation screening for asymptomatic AAI in DS patients.