70.Muscle_tendon_Dz

Question 1

what is the most common type of muscle-tendon injury

Answer 1

STRAIN or overstretchingusually occurs at the myotendinous unit/junctionoccurs when active contraction and passive extension occur simultaneouslymuscles that cross >2 joints are more prone to injury

Question 2

three stages of muscle strain

Answer 2

1. myositis and bruising2. myositis with mild tearing3. tearing of the fascial sheath with muscle fiber disruption

Question 3

two ways muscles heal

Answer 3

1. direct regeneration of myofibril (as long as sarcolemma survived insult and if endomysium is intact)2. fibrous scar tissue production

Question 4

surgery management of muscle stage 2 or 3 damage with tearing

Answer 4

–recommended for more severe injuries to appose the muscle and limit scar formation–surgery should take place once initial inflammation has receded (2-3 days)–evacuate/debride hematoma–long lasting monofilament absorbable suture–horizontal mattresses to oppose (use FASCIA and buttons/stents); can augment with additional sutures in apposition

Question 5

excessive scar tissue in muscle can reduce its function by how much

Answer 5

50%

Question 6

muscle tendon injury common in greyhound

Answer 6

avulsions/rupture of long head of triceps—can feel depression caudal and distal to scapulaalso see rupture of gracilius muscle

Question 7

what muscle must be damaged when a scapular displacement is seen

Answer 7

serratus ventralis muscle

Question 8

ruptured gracilus muscle

Answer 8

Greyhound, German shepherd, Foxhound

Question 9

most common muscles presenting with strain injury

Answer 9

iliopsoas (attaches to lesser trochanter)pain on direct palpation and hip extension/internal rotation25% iliopsoas and pectineus involved

Question 10

define muscle contracture

Answer 10

abnormal shortening of tissue rendering the muscle highly resistant to stretch–infraspinatus–quadriceps–gracilis/semitendinosus-flexor carpi ulnaris

Question 11

characteristic of infraspinatus muscle contracture

Answer 11

elbow adducted, forelimb abduction and externally rotatedcircumduction of limb during walkatrophy over the shoulderunilateral; biphasic lamenesstendinectomy along with release from fibrotic tissue

Question 12

quadriceps femoris muscle contracture

Answer 12

devastating consequence of femora fx in young dogs without rehab (stifle flexion)with contracture flexion is loss, stifle and tarsus is extendedprevention is key bc surgical correction has limited success

Question 13

gracilus and semitendinosus muscle contracture

Answer 13

German Shepherd dogjerk like raised affect leg with hyper flexion of tarsocrucal joint and internal rotation of metatarsusNOT painful

Question 14

flexor carpi ulnaris contracture

Answer 14

flexure deformity of puppies (or carpal hypo extension)bilateraltendon is palpably tightreversible with time +/- splints

Question 15

tendon healing

Answer 15

SLOW depends on influx of new fibroblasts to produce new collagen

Question 16

difference btwn sheathed and unsheathed or paratenon tendons and healing

Answer 16

paratenon (unsheathed) obtain vascular supply and source of cells from surrounding tissues; heal more rapidly; also termed vascular tendons: GASTROCNEMIUS, TRICEPSsheathed tendons are avascular; depend mush more on intrinsic blood supply for healing; also want minimal gap to minimize scar: DIGITAL FLEXOR TENDONS

Question 17

how much strength does a tendon have after suture repair (6 weeks post op)

Answer 17

at 6 weeks post op tendon only has 56% original strengthwill slowly increase to about 80% at a year post opnormal muscle contraction puts only 25-33% strain on tendons therefore strength at 6 weeks is sufficient for activity

Question 18

principles of tendon repair

Answer 18

1. restore Fx (tensile strength) and gliding function2. minimize gap/scar formation potential3. minimize debridement to maintain normal working length of tendon4. do NOT place incision onto of tendon (scar may form near tendon); keep incision parallel to tendon5. minimize crush handling of tendon (use small pins, needles to manipulate)6. monofilament nonabsorbable or long lasting absorbable7. minimize tension on tendon by extending/flexing nearby joints8. tendon suture patterns for approximation of tendon ends9. +/- augmentation with appositional suture around tendon with smaller size10. immobilization at least 3 weeks (bandage-cast,splint, transarticular screw, transarticular ESF)

Question 19

tendon suture patterns

Answer 19

1. locking loop (Kessler)-flat2. Bunnel3. F-N-N-F4. three loop pulley—round (increased resistance to pullout)5. continuous cruciate pattern–flat6. Krackow –flat

Question 20

common mistake for repair of severed digital flexor tendons

Answer 20

mistake is to only repair to superficial part of the tendon and missing the deep part of the digital flexor tendonsanimal wear bear weight on metatarsal/carpal pad –chronically lame with soresthere should be 4 deep and 4 superficial requiring repairflexion bandage (NWB and rids tension on tendons) 3 weeks; Normal bandage additional 3 weeks

Question 21

injuries to the tendon of origin of the biceps brachii muscle

Answer 21

O: supraglenoid tubercle avulsion or ruptureor medial displacement of tendon because of transverse humeral ligament rupturesurgery: tenodesis and/or repair of transverse humeral ligament

Question 22

injury to the long digital extensor tendon

Answer 22

avulsion off of the lateral aspect of the distal femur in immature large breed dogsor displacement from extensor groovetenodesis, reattachment of avulsed piece, or suture across the extensor groove to keep from displacement