European Journal of Applied Physiology

, Volume 118, Issue 7, pp 1301–1307 | Cite as

Biomechanical properties of the patellar tendon in children with heritable connective tissue disorders

  • Jacob K. Jensen
  • Rie H. Nygaard
  • Rene B. Svensson
  • Hanne D. Hove
  • S. Peter Magnusson
  • Michael Kjær
  • Christian Couppé
Original Article



Hereditary connective tissue disorders (HCTDs), such as classic Ehlers–Danlos syndrome (cEDS) and Marfan syndrome (MS) share overlapping features like hypermobility and tissue fragility. In clinical practice it remains a challenge to distinguish children and adolescents with HCTD from healthy children. The purpose of this study was to investigate the biomechanical properties of the patellar tendon and joint laxity (Beighton score) in children with HCTDs (n = 7) compared to healthy controls (n = 14).


The mechanical properties of the patellar tendon were assessed using simultaneous force and ultrasonographic measurements during isometric ramp contractions. Ultrasonography was also used to measure tendon dimensions. The HCTD children were matched with 2 healthy controls with regard to age, body mass index (BMI), sex and physical activity level.


The HCTD children had a greater degree of joint laxity (P < 0.01). Although, the patellar tendon dimensions did not differ significantly between the two groups, the HCTD children showed a tendency toward a larger patellar tendon cross-sectional area (CSA) (35%, P = 0.19). Moreover, stiffness did not differ between the two groups, but secant modulus was 27% lower in children with a HCTD (P = 0.05) at common force and 34% lower at maximum force (P = 0.02).


The present study demonstrates for the first time that children with HCTDs have lower material properties (modulus) of their patellar tendon, which may be indicative of general impairment of connective tissue mechanics related to their increased joint laxity.


Hereditary connective tissue disorders Tendon biomechanics Joint hypermobility Patellar tendon mechanics 



Hereditary connective tissue disorders


Classic Ehlers–Danlos syndrome


Marfan syndrome


Cross-sectional area


Magnetic resonance imaging


Body mass index



The present study was supported by Center for Healthy Aging (Nordea Foundation), University of Copenhagen, Lundbeck Foundation, Novo Nordisk Foundation, Danish Rheumatism Association, and the Danish Medical Research Council. RBS was supported by the Danish Council for Independent Research: Medical Sciences (DFF—1333-00052A).

Author contributions

CC conceived of the study, participated in its design and coordination and drafted the manuscript; SPM and HH participated in the design and interpretation of the data; JKJ and RN participated in the design and coordination of the study and performed the measurement; RBS participated in the design of the study and performed the statistical analysis; MK conceived of the study, and participated in its design and coordination and helped to draft the manuscript. All authors read and approved the final manuscript.

Supplementary material

421_2018_3862_MOESM1_ESM.png (13 kb)
Supplementary material 1 (PNG 13 KB)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Jacob K. Jensen
    • 1
  • Rie H. Nygaard
    • 1
  • Rene B. Svensson
    • 1
  • Hanne D. Hove
    • 3
    • 4
  • S. Peter Magnusson
    • 1
    • 2
  • Michael Kjær
    • 1
  • Christian Couppé
    • 1
    • 2
  1. 1.Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
  2. 2.Department of Occupational and Physical Therapy, Bispebjerg HospitalUniversity of CopenhagenCopenhagenDenmark
  3. 3.Section of Rare Diseases, Department of Clinical GeneticsCopenhagen University HospitalCopenhagenDenmark
  4. 4.The Raredis Database, Department of Clinical GeneticsCopenhagen University Hospital RigshospitaletCopenhagenDenmark

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