OCS: soft tissue injury and repair

Question 1

What is the body’s initial response to soft tissue injury?

Answer 1

Erythema (rubor), swelling (tumor), elevated tissue temperature (calor), and pain (dolor); the first three are caused by local vasodilation, fluid leakage into extracellular and extravascular spaces, and impaired lymphatic drainage. Pain is the result of mechanical distention and pressure of the soft tissue and chemical irritation

Question 2

What is the body’s initial response to soft tissue injury?

Answer 2

Erythema (rubor), swelling (tumor), elevated tissue temperature (calor), and pain (dolor); the first three are caused by local vasodilation, fluid leakage into extracellular and extravascular spaces, and impaired lymphatic drainage. Pain is the result of mechanical distention and pressure of the soft tissue and chemical irritation

Question 3

Describe basic vascular and cellular activities associated with the inflammatory reaction:

Answer 3

Initial vasoconstriciton regulated by norepinephrine, serotonin released by mast cells will extend the vasoconstriction. Migration of leukocytes adhere to the wall and chemotaxis (white blood cells enter) starts phagocytosis to remove debris

Question 4

Key chemical mediators in inflammatory process:

Answer 4

Histamine: increases permeability Seratonine: vasoconstrictor Kinins: increases permeability Prostaglandins: pro-inflammatory, sensitize pain receptors, attract leukocytes, antagonize vasocontricts to increase permeability

Question 5

What is the primary mode of action for aspirin, NSAIDS, and steroids?

Answer 5

inhibition of prostaglandin synthesis by deactivation of a key enzyme (cyclooxygenase)

Question 6

Which cell type is prominent in the proliferative and matrix formation of connective tissue healing?

Answer 6

Fibroblasts - responsible for synthesizing and secreting most of the fibers and ground substance of connective tissue

Question 7

Describe the elements that comprise the connective tissue matrix:

Answer 7

Fibrous elements: collagen, elastin, and reticulin Ground substance: water salts, and glycosaminoglycans

Question 8

Purpose of the tissue matrix:

Answer 8

provides strength and support to the soft tissue, serves as the mans for diffusion of tissue fluid and nutrients

Question 9

What general factors affect connective tissue repair after tissue injury?

Answer 9

Availability of: blood, proteins, minerals, and amino acids Enzymes and hormones, mecahnical stress, infection, presence of medications, and disease also effect repair.

Question 10

How do steroids and anti-inflammtories affect the healing process:

Answer 10

Steroids: suppress fibroblasts resulting in diminshed deposition of collagen fibers and reduce tensile strength Anti-inflammatories: inhibit protein syntehsis affecting wound healing and scar formation

Question 11

Influence of nutrition on soft tissue repair?

Answer 11

Collagen synthesis needs proper nutrients, especially Vitamins A & C. Glucosimine is critical compound in connective tissue repair and production.

Question 12

What role does aging play in altering the soft tissue injury healing process?

Answer 12

Attenuated metabolic activity, decrease vascular supply, diminished cellular biosynthesis, delayed collagen remodeling, and decreased wound strength; regardless of this clinical studies indicate that older patients who undergo surgical Tx had adverse effects to healing related to aging.

Question 13

Tendinitis vs Tendinosis?

Answer 13

Tendinitis: microscopic tear at muscle tendon junction, attended by localized swelling and tenderness Tendinosis: degenerative process and manifests as chronic irritation or inflammation at the tendon-bone junction

Question 14

What is paratenonitis?

Answer 14

Thickening and inflammation of the paratenon, a double layered sheath of loose areolar tissue is attached to the outer connective tissue.

Question 15

How does Tx differ for tendinitis and tendinosis?

Answer 15

Tendinitis: conservative to reduce inflammation and tissue stresses Tendinosis: focuses on controlled eccentric training program often 10-12 wks and may require surgical intervention to eliminate the diseased area of the bone-tendon interface

Question 16

What changes occur with immobilization?

Answer 16

Tissue becomes thicker and weaker: 9 wks of immobilization results in 50% reduction in normal breaking strength of MCL, contracture formation secondary to increase in collagen crosslinks

Question 17

How does stress and motion affect connective tissue repair after injury?

Answer 17

Scar tissue forms earlier, improve orientation, prevents adhesions, stronger tendon and ligament healing,

Question 18

What is the effect of ultrasound and electrical stimulation have on the early stage of healing?

Answer 18

some evidence to suggest that they improve tensile strength by limiting inflammation while encouraging protein synthesis or fibroplasia

Question 19

Define myositis ossificans:

Answer 19

formation of heterotopic bone in soft tissue after contusion or trauma involving muscle

Question 20

Myositis ossificans occurs in what population and areas most frequently?

Answer 20

Males ages 15-30, thigh contusions or fractures/dislocations of the elbow

Question 21

what time frame does myositis ossificans appear on x-ray?

Answer 21

3-4wks after initial injury

Question 22

After ligament and tendon repair, when is the soft tissue the strongest and the weakest? Clinical implications:

Answer 22

strongest during initial implant or repair, but during the first few months strength decreases before it regains most of the strength by 1 yr post op. Clinically: protect the graft early, encourage closed chain to avoid shear forces, and emphasize maximal motor unit activation.

Question 23

Does the location of a ligament or tendon repair influence the rate of healing? Why?

Answer 23

Insertion sites tend to heal faster than mid-substance repairs, primarily because of availability of blood supply. Presence of a synovial lining and fluid would also increase the healing rate.

Question 24

What is the response of articular cartliage to chondroplasty (microfracture tech, abrasion, drilling) of the undersurface of the patella?

Answer 24

Micro fx process: tiny holes are drilled into the subchondral bone to produce a “super clot”, over a period of 8 wks or more it heals with a hybrid mixture of fibrocartilage and collagen (type II hyaline-like), which functions like articular cartilage.

Question 25

Describe the scientific evidence supporting articular cartilage repair:

Answer 25

Research supports femoral lesions and is encouraging for focal chondral defects. Patellar lesions do poorly secondar to shear forces, and generalized OA also does not do well.

Question 26

How does electromagnetic and electric fields effect articular cartilage repairs?

Answer 26

can lead to a sustained upregulation of growth factors, enhancing viability

Question 27

What growth factors are involved with soft tissue healing?

Answer 27

Chemotactic factors: prostaglandins, complement, platelet-derived growth factor (PDGF), angiokines Competence factors: activate quite cells, PDGF, prostaglandins Progression factors: stimulate cell groth such as IL-1 and somatomedins Enhancing factors: fibronectin, osteonectin

Question 28

Effect of NSAIDs on muscle recovery?

Answer 28

short term use <1 wk after muscle strain may improve recovery, but long term use >1 month may result in decreased recovery

Question 29

What factors affect allograft strength?

Answer 29

Freeze drying and radiation decrease strength. Allografts have a slower less predictable recovery than autografts.

Question 30

What growth factors may aid in soft tissue repair?

Answer 30

Platelet-rich plasma (PRP) in animal trials improve collagen abundance and organization Macrophage-secreted myogenic factors: effect muscle repair Chondrocyte and bone morphogenetic proteins (BMP) have promise with improving cartilage repair.