Chapter 70: Muscle and Tendon Disorders

Question 1

Where do muscle strains most commonly occur?

Answer 1

At the musculoskeletal junction

Question 2

Name the 3 stages of muscle strain (overstretching)?

Answer 2

• Stage 1: Myositis and bruising but architecture intact
• Stage 2: Myositis and some tearing of fascial sheath
• Stage 3: Tearing of fascial sheath, muscle fiber disruption and hematoma formation

Question 3

What are the two types of tendons?

Answer 3

Paratenon lined (vascular) (gastroc, triceps insertions)
sheathed tendons (avascular) (digital flexor tendons)

Question 4

At 6 weeks post repair, a tendon has what % of it’s original strength?

Answer 4

56%

Question 5

At one year post repair a tendon has what % of its original strength?

Answer 5

79%

Question 6

Name three patterns of sutures for repairing tendons?

Answer 6

3 loop pulley
Locking loop
Krackow

3LP has increased resistance to pull-out
3LP better for round tendon, others for flat tendons

Question 7

Muscle injuries are common but rarely cause clinical issues, what are two exceptions?

Answer 7

Specific injuries in athletic dogs
Injuries that lead to muscle contracture

Question 8

What is different between muscle injuries and tendon injuries?

Answer 8

Tendon injuries commonly present with serious clinical signs.

Question 9

What are the three classifications of muscle injury?

Answer 9

Contusion (blunt injury)
Strain (overstretching, most common)
Lacerations (sharp injuries - trauma from cuts, sharp fractures or iatrogenic)

Question 10

How does muscle healing occur?

Answer 10

Direct regeneration of myofibrils and formation of scar tissue
The fastest healing is through day 14, then it slows

Question 11

Any gap in tendon reapposition heals as what?

Answer 11

scar tissue

Question 12

How does healing differ between paratenon-lined and sheathed tendons?

Answer 12

Paratenons are vascular and can send in vascular buds to tendon - better chance for rapids healing
Sheathed need to depend on inrinsic blood supply

Question 13

What occurs during the first 4-5 days after tendon repair?

What needs to happen in the first 3 weeks, after 3 weeks?

Answer 13

The tendon ends lose holding power, then gradually increase over the next 2 weeks

Sutures must entirely resist any gap formation for 3 weeks
After 3 weeks, need normal loading for correct alignment of collagen as heals ***normal daily forces only require 25-33% of tendon capacity

Question 14

The pictured tendon suture that looks like a shamrock is which pattern?

Answer 14

Kessler or locking loop
This is the most versatile suture
The transverse part must pass superficial to the longitudinal to grab bundles of tendon fibers

Question 15

The pictured tendon suture with the knot off to the side is which pattern?

Answer 15

Three loop pulley.
It is best suited for round tendons.
The diagram is numbered for the order of needle passage (there are 6)

Question 16

All tendon sutures are what type of pattern and why is this important?

Answer 16

They are HOLDING, not for pulling tendon together. Tendon should be held apposed while these are placed.

Question 17

What can be placed to help manipulate tendon?

Answer 17

Needles or K-wires through the normal bodies.

Question 18

Locking loop (Kessler) and Krackow patterns allow tendon bundles to be grabbed. How does three loop pulley work to hold tendon?

Answer 18

It has increased resistance to pull-out.

Question 19

What should you do before apposing tendon?

After placing your holding sutures, what do you do?

Answer 19

Debride the ends.

Place epitendinous sutures to help appose - horizontal mattress around the circumference.