Tendon Healing and Grafting Flashcards Preview

Upper Extremity > Tendon Healing and Grafting > Flashcards

Flashcards in Tendon Healing and Grafting Deck (10):
1

Describe the strustural composition of a tendon

  • Cellular
    • tenoblasts- immature tenocytes
    • tenocytes - spindle fibroblasts (90%)
    • synovial cells
    • chondrocytes (at insertion pts)
  • Collagen type 1
    • 3 troprocollagen fibrils ->fiber -> fiber bundle -> fascicles
  • Ground substance
    • HA, PG, LP GAG

2

Describe the blood supply of a tendon

STARRED FOR REVIEW?

Extrinsic (outside of synovial sheath)

  • Paratenon 
  • Mesotenon - via vincula (Longus & brevis)
  • Epitenon - sourrounded by paratenon

Intrinsic (wihtin synovial sheath of within tendon

  • myotendinous and osteotedinous jxs
  • Endotenon

(a different source says intrinsic supply is osseo- and myotendinous jxn, and extrinsic is paratenon [for extra-synovial] and vincula [for intra-synovial]????)

3

Describe tendon healing

INFLAMMATORY PHASE (1ST WEEK)

  • Hematoma, recruitment of macrophage and PMN
  • Epitendon cells proliferatie
  • Fibroblasts invade and produce collage 3

PROLIFERATIVE PHASE (WK 1- WK3)

  • fibroblasts deposit collage 3, ECM
  • epitendon >endotenon key for collagen deposition

REMODELLING PHASE (>6WKS)

  • drop in cellularity and collagen 3 production -> rise in collagen 1 production and reorientation

4

What factors promote extrinsic versus intrinsic healing?

Extrinsic healing (invasion of cells from surrounding and formation of adhesions)

  • poor tendon apposition
  • immobilization
  • crush
  • bacterial contamination
  • damage of surrunding structures (devasculaized, fracture)

Intrinsic healing (I,P,R stages)

  • mobilization
  • good tendon apposition
  • early repair
  • tendon sheath preservation
  • limited dissection

5

What are potential sites for tendon harvest and technique

  • Palmaris longus
    • 3mm, 15cm, 15% of population doesnt have one
    • ulnar to FCR
  • Plantaris
    • 2mm, 25cm, 5% of population doesnt have one
    • medial and anterior to achilles, 5cm vertical incision
  • Long toe extensor
    • of D2,3,4

6

WHAT IS THE CELLULAR STRUCTURE OF TENDON

  • Tenoblasts and tenocytes - 90%
  • Synovial cells, chrondrocytes, capillary endothelial cells - 10%

7

8

what structure detects changes in tendon tension / pressure ?

  • golgi tendon organ

9

describe extrinsic vs intrinsic tendon healing

  • extrinsic - tendon relies on immobilization and adhesions for repair (original thought was that tendons had no intrinsic capacity to heal)
    • fibroblast ingrowth, neovascularization, fibrosis, adhesion
  • intrinsic - tendon responsible for its own repair
    • 3 stages of tendon healing
    • inflammatory
    • proliferative
    • remodelling
  • likely tendon healing is a combination of extrinsic and intrinsic methods; but knowledge that tendon can revascularize from paratenon (extra-synovial) or vincula/synovial diffusion (intra-synovial)

10