The Biomechanical, Biochemical, and Morphological Properties of 31 Human Cadaveric Upper Limb Tendons: An Open Access...

Upper limb tendon/ligament injuries are common in sport and may require reconstruction using grafts or tendon transfers. Understanding tissue-specific properties is key to improving graft selection criteria and developing new interventions.

To characterize morphological, biomechanical, and biochemical properties of clinically important upper limb tendons, expanding available data on upper and lower limb tissues that are commonly injured or used as grafts.

Descriptive laboratory study.

A total of 31 individual upper limb tendons were each retrieved from 8 fresh-frozen human cadavers (3 female, 5 male; aged 49-65 years): supraspinatus, infraspinatus, subscapularis, long head of biceps, distal biceps, distal triceps, brachioradialis, flexor carpi radialis, flexor carpi ulnaris, palmaris longus, extensor carpi radialis longus and brevis, extensor carpi ulnaris, flexor pollicis longus, abductor pollicis longus, extensor pollicis brevis and longus, extensor indicis proprius, extensor digiti minimi, and from the second to fifth digits, flexor digitorum superficialis and profundus and extensor digitorum communis. Outcome measures included tissue length; cross-sectional area, and major/minor axes; failure load; ultimate tensile strength (UTS); failure strain; elastic modulus; sulfated glycosaminoglycan (sGAG) and hydroxyproline content. Differences were analyzed using mixed linear regression models.

Rotator cuff tendons were distinct, exhibiting large, flat cross-sections with high failure loads and sGAG, and low UTS. Supraspinatus was significantly weaker with more sGAG than infraspinatus and subscapularis. Tendon UTS and elastic modulus were largely similar between elbow, wrist, and hand tendons. Exceptions included higher and lower material properties of the extensor pollicis brevis and flexor carpi ulnaris, respectively, than other distal upper limb tendons. Extensor tendons generally had higher sGAG than flexors with significant differences at the wrist and thumb, while hydroxyproline content was significantly higher in digital flexors versus extensors in the fingers.

These findings enhance understanding of upper limb tendon properties, providing novel data to inform graft selection and tailor alternative engineered or regenerative strategies.

The combined upper/lower limb data sets include 48 unique appendicular tendons and ligaments sourced from the same donors and evaluated using consistent methodologies, providing a robust comparative database to aid selection of suitable donor tendons for the repair/reconstruction of injured tendons/ligaments and the development of graft materials.