Definition of Joint Hypermobility
Joint hypermobility is defined as a range of joint movement that exceeds normal limits, taking into account the individual's age, gender, and ethnic background. 1
Clinical Assessment and Diagnostic Thresholds
Joint hypermobility is objectively measured using the Beighton scoring system, a standardized 9-point scale that evaluates five specific body areas: 2, 3
- Fifth finger passive dorsiflexion >90 degrees (1 point per side) 4
- Thumb passive apposition to flexor surface of forearm (1 point per side) 4
- Elbow hyperextension >10 degrees (1 point per side) 4
- Knee hyperextension >10 degrees (1 point per side) 4
- Forward bend with palms flat on floor while keeping knees extended (1 point) 4
Age-Specific Diagnostic Criteria
The threshold for diagnosing generalized joint hypermobility varies by age group: 2, 3
- Prepubertal children: Beighton score ≥6/9 points 2
- Adults under 50 years: Beighton score ≥5/9 points 2
- Adults over 50 years: Beighton score ≥4/9 points 2
Distinction Between Hypermobility and Hypermobility Syndrome
Joint hypermobility alone is not a disease—it represents the extreme end of normal joint range of motion and can even confer benefits in terms of mobility and agility. 1, 5 However, when joint hypermobility is accompanied by musculoskeletal symptoms (such as pain, dislocations, or subluxations), it is termed joint hypermobility syndrome (JHS) or hypermobility syndrome. 1, 5
Key Clinical Distinction
The critical difference is symptomatology: 1
- Asymptomatic joint hypermobility = benign finding, often familial (termed "familial benign joint hypermobility") 6
- Symptomatic joint hypermobility = joint hypermobility syndrome or hypermobility spectrum disorder requiring clinical management 1, 5
Relationship to Connective Tissue Disorders
Joint hypermobility is a cardinal feature of several heritable connective tissue disorders, most notably hypermobile Ehlers-Danlos syndrome (hEDS), where it serves as a major diagnostic criterion. 2, 3 However, joint hypermobility also occurs in: 6
Important caveat: Many features associated with these syndromes, including joint hypermobility, occur commonly in the general population for both genetic and non-genetic reasons, making isolated hypermobility insufficient for diagnosing a specific connective tissue disorder. 6
Clinical Significance Beyond the Musculoskeletal System
While joint hypermobility primarily affects joint range of motion, it frequently associates with multisystem manifestations when part of a syndrome: 2, 5
- Cardiovascular: Aortic root dilation occurs in 25-33% of hypermobile EDS cases 2
- Gastrointestinal: Up to 98% of hEDS patients experience GI symptoms 2, 3
- Autonomic: Postural orthostatic tachycardia syndrome (POTS) affects many patients 2
- Dermatologic: Easy bruising and skin hyperextensibility 2
Critical pitfall to avoid: Do not dismiss joint hypermobility as merely a benign finding without assessing for associated symptoms or systemic features that might indicate an underlying connective tissue disorder requiring specialized management. 1, 5