TENDONS DR.ABHINAV.S.KESARKAR

FIRST YEAR JUNIOR RESIDENT

PDMMC

AMRAVATI

TENDONS

Tendons are anatomic structures interposed between muscles and bones transmitting the force created in the muscle to bone, and, in this way, making joint movement possible.

They are one of the strongest connective tissue in human body withstanding numerous mechanical forces.

They are viscoelastic structures exhibiting both elastic and viscous behaviour.

Paratenon covered tendons e.g., patellar, achilles tendons have rich vascular supply and thus heal better often injured due to trauma and most often fail

at the musculotendinous junction tendon-bone junction

Sheathed tendons e.g., hand flexor tendons less vascularized and have avascular areas that

receive nutrition by diffusion often injured due to laceration and at risk

for adhesions

Tendon composition Water Collagen ( type I and type III ) -> 90% 1-5% proteoglycan (decorin & aggrecan) 0.2% inorganic components copper,manganese

and calcium

Tendons are basically group of collagen bundles Separated by endotenon and covered by epitenon.

STRUCTURE

collagen(protocollagen)

Microfibrils

subfibrils

Fibrils

Fascicles

Tendon unit

Tendon cells or Tenocytes Tenocytes are fibroblast-like differentiated

cells that form the mature tendon. Tenocytes synthesize the extracellular matrix, inducing assembly of early collagen fibers, which are the basic units of the tendon

TENOCYTES PROPERTIES

Are spindle shaped cells arranged in direction of muscle loading in arrays

Secrete collagen type I predominantly (95 %) but also secretes type III collagen in small

amounts

Help in healing of tendons

BIOMECHANICAL EFFECTS

Exercise strengthens tendons Immobilisation has detrimental effects. Tensile strength decreases with age. Heat decreases tensility/strength . Strength varies with

hydration,pH,tempreature. Tendons can bear 5-10% more tension as

compared to bone.

STAGES OF TENDON HEALING

Hemostasis Platelets initiate coagulation cascadeFibrin clot and fibronectin interaction leading to chemotaxis to stabilize torn tendon edges

5-15 min

Inflammation Fibroblasts produce type III collagenmacrophages help initiate healing and remodeling

1-7 days

Organogenesis Tissue modeling via large amounts of disorganized collagen and angiogenesis

7-21 days

Remodeling Tissue remodeling replacing type III collagen to type I collagen

Upto 18 mths

STRESS – STRAIN CURVE

THANK YOU