Small Animal Muscle, Tendon, Ligament Injury Flashcards
how does the muscle tendon units activate joint motion
contraction
injuries to the muscle-tendon unit
strains
What are tendons made of
dense, parallel colalgen fibers (85% Type I)
proteoglycan matrix and fibroblasts
injuries to the ligaments are called
sprains
How do vascular tendons differ from vascular ones
Vascular: short and large, have paratenon (loose connective tissue with blood vessels)
Avascular: long, fine tendons, vessels penetrate tendon sheath (hypovascular)
What are examples of vascular tendons
short and large tendons like the triceps and achilles
What are examples of avascular tendons
long and fine tendons like the digital flexors and biceps
Paratenon
loose connective tissue with blood vessels present in vascular tendons
Are vascualar or vascular tendons sheathed
avascular- vessels penetrate the tendon sheath
What do ligaments do
support and stabilize joints
incapable of contracting
tolerate minimal elongation <10%
Relatively avascular = less healing capacities
Why do ligaments have less healing capacities
they. are relatively avascular
Most joints have collateral ligaments except
the hip joint
How do muscle and tendons heal
very similar to skin
tensile forces create a gap
gap healing results in scar tissue
scar tissue = poor function
How do vascular tendons heal
Tendon and paratenon (blood supply) laceration
-Collagen synthesis within days
-Collagen fibers realign (3-4 weeks)
80% normal within 1 year
How do avascular tendons heal
tendon and sheath (avascular) laceration
tendons distract in sheath = gap
Failure to do surgery = nonunion of tendon ends
complete rupture or avulsion of attachments
Complete dysfunction with strain or joint instability with sprain (luxation)
Third degree MT injury
Different classifications of MT injuries
First degree (Bruise) : hemorrhage but intact fibers (contusion- bruise)
Acute pain, inflammation + swelling, should resolve over 7-14d
Second degree (Partial Tear) : Hemorrhage + partial fiber disruption (variable elongation)
Acute pain, inflammation, swelling
Doesnt improve or worsen
Third degree (Complete) : complete rupture or avulsion of attachments
Complete dysfunction with strain or joint instability with sprain (luxation)
Hemorrhage + partial fiber disruption (variable elongation)
Acute pain, inflammation, swelling
Doesnt improve or worsen
Second degree MT injury
hemorrhage but intact fibers (contusion- bruise)
Acute pain, inflammation + swelling, should resolve over 7-14d
First degree MT injury
How do you diagnose ligament injury
-Visible instability/injury/stance abnormality
-Palpation (pain or swelling)
-Ultrasound/MRI
-Stress radiographs: standing, manual lateral/ medial force
Where can muscle tendon injuries occur
1) Origin and Insertion (avulsions)
2) Muscle belly
3) Tendon
but tend to occur most commonly at musculotendinous junction
Most common place for muscle tendon injuries to occur
commonly at musculotendinous junction
occurs when a piece of bone is pulled off at the origin/insertion of a tendon
avulsion fracture
How do you diagnose low grade MT injuries
Passive Range of Motion: oppsotive of function to elastic end feel
Biceps brachii does elbow flexion and shoulder extension, which means the passive range of motion is stretch on
Elbow extension
Shoulder flexion
If you have elbow dysplasia, would elbow flexion or extension cause pain
Elbow extension
You flex a dog’s shoulder and extend their elbow. If this elicits pain, what 4 things could be occuring
Supraspinatus myotendinopathy (Flexing Shoulder)
Shoulder OCD
Biceps myotendinopathy (flexed shoulder and extending elbow)
Elbow dysplasia (extending elbow)
In the regeneration of muscle, new muscle cells develop from
undifferentiated satellite cells
Scar tissue, the proliferation of fibrous tissue is likely to occur when
the endomysium is damaged
the less vascular supply available, the more scar tissue will form
Muscle fibre regeneration will occur when
endomysium is intact
What are surgical goals for MT injury healing
minimal gap formation = anatomic apposition and maintain that position
preserve blood supply = minimal trauma/implants
Preserve gliding function?
How do you preserve the blood supply to enhance MT injury healing
-Atraumatic tissue/tendon handling
-Mobilization of healthy tendon ends
-Skin incision not over the injury
-If feasible, close the paratenon
If you gap is _____ then this significantly impairs tendon healing *
> 3mm
need to choose a suture pattern that avoids gaps >3mm
Why do gaps >3mm impair tendon healing *
decreased rigidity and ultimate tensile strength (10-42 days post operatively)
No significant increase in ultimate tensile strength and rigidity until 42 days after repair
repairs with gap >3mm have significantly weaker for at least 6 weeks after repair (compared to tnedons without gap)
What suture should you ensure to your tendon repair has gaps that are <3mm
easy passing
good knot security
non-irritant
adequate strength
usually Nylon/ polypropylene 2-0/3-0
pattern: 3-loop pulley, baseball/locking loop (if 3-loop pulley not available)
3-loop pulley suture pattern is prefered for
larger tendon repairs
For flat tendons (ie gluteal), what suture patterns do you not want to do?
Ford-interlocking or Bunnell-Mayer (not good for 3mm gap)
Use: Baseball suture pattern
For large tendons, what suture pattern do you want to use
3-loop pulley suture
For flat tendons (ie gluteal), what suture patterns do you want to use
Baseball or continuous cruciate pattern
For small tendons, what suture pattern do you want to use
Locking Loop (modified Kessler)
-Requires precise suture passage (otherwise becomes a mattress)
-Useful for flat tendons
-Close paratenon with simple pattern using fine suture
Locking Loop (modified Kessler) is used for
Small tendon repair
-Requires precise suture passage (otherwise becomes a mattress)
-Useful for flat tendons
-Close paratenon with simple pattern using fine suture
T/F: Tendon suture construct can withhold normal forces during walking
False- you need tendon immobilization
-gradually increase tension across tendon repair like walking bar cast/ex-fix
combine with early PT
How do you gradually increase tension across a tendon repair in dogs
-gradually increase tension across tendon repair like walking bar cast/ex-fix
combine with early PT
What commonly cause SDF/DDF injury in dogs
lawn edge sharp edges
How do you fix SDF/DDF injury in dogs
1) Make sure the wound is clean: wet-dry bandages if needed (tendon retraction/identification can be problem if left too long)
2) Identify, repair each of the tendons separately
DDF/SDF= most important digit 3+4
If possible 3-loop pulley or small tendons (locking loop)
3) Post-op: walking bar for 6 weeks (change weekly) followed by soft padded for 2 weeks afterafter
4) Rehab exercises in walking cast, carpal flexion bandage, orthosis and during post-splint recovery (week 6-14 weeks)
With DDF/SDF injury in dogs, why should you start with the repair of digits 3 and 4
because those are the weight bearing digits
For DDF/SDF injury in dogs, what should you do for post-operative care
walking bar for 6 weeks (change weekly) followed by soft padded for 2 weeks thereafter
-if you go longer than 6 weeks, permanent damage to the joint = permanent immobilization
For a complete traumatic disruption of major tendons, what general statement is correct?
Group of answer choices
A) These injuries are unlikely to cause a lasting lameness if treated with external coaptation
B) They generally should be treated surgically (to appose disrupted tendon ends) and supported for approximately 6 weeks thereafter with splints/casts.
C) These injuries can be treated with orthotics instead of surgery
D) Surgical repair with a locking loop is indicated
B) They generally should be treated surgically (to appose disrupted tendon ends) and supported for approximately 6 weeks thereafter with splints/casts.
The 3-loop pulley suture pattern is reserved for
surgical repair of large, round tendons
everything that attaches at the tuber calcus
-Gastrocnemius (lateral)
-SDFT (cap)
-Conjoined tendons of (medial): biceps femoris, gracilis, semitendinosus
Common calcanean tendon
Common calcanean tendon is made of
-Gastrocnemius (lateral)
-SDFT (cap)
-Conjoined tendons of (medial): biceps femoris, gracilis, semitendinosus
Does the DDFT or SDFT attach to the tuber calcis
SDFT
What are the dwo different kinds of achilles tendinopathy
1) Acute, traumatic injury = true laceration, treat like any other tendon laceration
2) Chronic degenerative injury: hunting dogs, frequently bilateral, check for underlying disease (endocrine, coagulopathy)
Apposition of healthy tendon is difficult
How might Achilles tendinopathy be bilateral
chronic degenerative injury seen in hinting dogs
check for underlying disease (endocrine, coagulopathy)
How is surgical treatment of chronic degenerative Achilles tendinopathy
apposition of healthy tendon is difficult because it is chronic and degenerative
Plantigrade stance AND flat paw with stifle in extension means that
there is a complete rupture of all components of the common calcaneal tendon
Plantigrade stance (dropped hock) and crab-claw-like stance means
that the SF is intact
-tarsus flexes more (dropped) because gastronemius is main extender of the hock
-toes are flexes because SDFT is still intact
How do you repair traumatic Achilles tendinopathy
-repair each tendon individually if possible
-3 loop pulley pattern w prolene suture (2-0)
-Additional epitenon/paratenon sutures (usually 3-0//4-0 PDS)
-Hock maintained in extension postop
Cast vs Ex-fix for 6 weeks max
At CSU: orhtosis and gradually increase ROM
alternative options: Orthoses, stem cell treatment, shockwave, laser, PRP
Orthoses for Achilles tendinopathies
for early Type 2c- sole treatment
supportive post-op for surgical repair
downstage to sorts brace long term
avoid external coaptation and Ex-fix which cant introduce ROM over time
