Oral Presentation ANZBMS-MEPSA-ANZORS 2022

Histological characterisation of different tendons of the human hand (#60)

Samantha A Hefferan 1 2 , Dylan M Ashton 1 2 , Carina L Blaker 1 2 , David Chang 3 , Richard Lawson 3 , Christopher B Little 2 4 , Elizabeth C Clarke 1 2
  1. Murray Maxwell Biomechanics Laboratory, Kolling Institute, Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW, Australia
  2. Faculty of Medicine and Health, The University of Sydney , Sydney, NSW, Australia
  3. Department of Hand Surgery, Royal North Shore Hospital, Northern Sydney Local Health District, Sydney, NSW, Australia
  4. Raymond Purves Bone and Joint Research Laboratories, Kolling Institute, Institute of Bone and Joint Research, Royal North Shore Hospital, Sydney, NSW, Australia

Tendons play an important role in the musculoskeletal system, however, they are prone to injury, pathology or disease which can impede normal functioning. Hand tendons are no exception, and highly prevalent in soft-tissue injuries1-2. Currently there is little known about structural variations between different tendons and what implications such variability has on clinical outcomes. This study aims to histologically characterise and compare a range of different human hand/wrist tendons.

Formalin-fixed paraffin-embedded samples from 17 different hand/wrist tendons (Figure 1a) (6 human cadavers; fresh-frozen; 3 males, 3 females; 49-62 years; no history of musculoskeletal disease or injury) were sectioned and stained with either Haematoxylin and Eosin (HE), Toluidine Blue (TB) or Picrosirius Red (PSR). Scores assessed cellularity and cell-morphology (H&E), proteoglycan content (TB), and collagen alignment and crimp wavelength (PSR). Outcomes between functionally pooled tendon groups (Figure 1a) were analysed using a Kruskal-Wallis test with Dunn’s correction for multiple comparisons.

A total of n=102 specimens were included for analysis. There were significantly more rounded cell nuclei (Figure 1b) in Deep Digital Flexors versus Wrist Flexors (p=0.0016) and Digital Extensors (p=0.0003); and Superficial Digital Flexors versus Wrist Flexors (p<0.0001) and Digital Extensors (p<0.0001). Proteoglycan staining in Wrist Flexors was significantly less than Deep Digital Flexors (p=0.0059) and Superficial Digital Flexors (p=0.0340). Collagen structure was less aligned in Deep Digital Flexors versus Wrist Flexors (p=0.0333) and Digital Extensors (p=0.0002); and Superficial Digital Flexors versus Digital Extensors (p=0.0268).

These results highlight important previously unidentified differences between human hand/wrist tendons. Future investigations will seek to identify further cellular, molecular and biomechanical variations and facilitate research on tendon structure-function relationships. With injury of the hand a serious and prevalent health condition, better characterisation of tendon similarities/differences could aid understanding of tendon injury and healing, and provide design targets for engineered tissues.

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  1. Clayton R. and Court-Brown C., Injury, 2008. 39(12), 1338-1344
  2. Colzani G. et al., J Hand Microsurg, 2016. 8(1), 2-12