Large Animal Sx - Musculoskeletal Sx & Conditions 2

drraythe's version from 2015-11-24 20:13

Foot rot + Corns

Question Answer
what is Interdigital necrobacillosis /"Foot Rot"/"Foul Foot"?An infection of the soft tissue of the foot that can progress to involvement of bones and joints
what causes Interdigital necrobacillosis /"Foot Rot"/"Foul Foot"?Caused by Fusobacterium necrophorum, which is Common in the environment.. Requires an injury in the interdigital space to gain access to deeper structures.
what are the clinical signs of Interdigital necrobacillosis /"Foot Rot"/"Foul Foot"?Sudden onset of very painful lameness (Usually animals only touch the ground with the toe). Skin and soft tissue in the interdigital area becomes red and swollen (Top of hoof to dewclaws will be swollen!!). *Dewclaws will be farther apart that those of a normal foot. In early cases (those that respond well to parenteral antibiotics) the swelling will be symmetrical
how do you tx/ manage Interdigital necrobacillosis /"Foot Rot"/"Foul Foot"?Early antibiotic treatment usually effective (Oxytetracycline/Penicillin/Nuflor(Florfenicol)/Excenel(Ceftiofur) ).
If you see swelling like this, what do you suspect? Interdigital necrobacillosis /"Foot Rot"/"Foul Foot" causes swelling between the dewclaws
When is surgery to tx foot rot NOT indicated?Not Indicated If Fetlock Jt Is Infected
when IS surgery to rx foot rot indicated?Severe cases might involve deeper tissue and require amputation of claw or extensive surgical drainage with removal of involved tendons and or arthrodesis of involved joints
what are two kinds of sx procedures to consider for tx severe cases of foot rot where the deeper tissues are involved? Implications/results of each sx?(1) Debride/Joint Ankylosis--> Animal can remain in the herd. (2) Claw Amputation--> Salvage Procedure (can't stay in herd, once healed, culled)
explain how to do a claw amputation in the case of severe foot rot in which the fetlock joint is not involved(claw amputation= salvage procedure) Lateral recumbency with the involved digit up. Most commonly performed with local intravenous anesthesia--> A tourniquet is placed on the limb in the proximal metacarpal/tarsal area a vein is identified, catheterized and local anesthetic is injected (ring block can be used) . Then two options for amptuation: Crude and more sophisticated (sophisticated on diff card) (1) crude method: Place a wire saw in the interdigital space, Position the ends of the saw proximal to the foot so that the wire is at approximately 45 degrees to the limb. Pull alternately on the ends of the saw to cut through bone connective tissue and skin so that the cut is made through the middle of the 1st phalanx. Ligate if needed, apply padding and snug bandage, redress in 2-3d.
What is a more sophisticated way to perform a claw amputation in the case of severe foot rot which doesnt involved the fetlock joint?Make incision on the dorsal and caudal aspect of the digit from the coronary band to just distal to the fetlock--> Make an incisions just proximal to the coronary band on the medial and lateral aspects of the digit joining the dorsal and caudal incisions. Dissect the skin and subcutaneous tissue free from the underlying bone to produce a lateral flap of skin. Position a wire saw in the interdigital space, Position the ends of the saw proximal to the foot so that the wire is at approximately 45 degrees to the limb and make a cut through the middle of the 2nd phalanx. ligate as necessary, Suture the skin flap to the dorsal and caudal incisions and, if possible, to the skin on what was the axial side of the claw (Most times it is not possible to close the ventral aspect of the wound completely!) Then apply padding and snug bandage, redress in 2-3d
Removal of diseased tissue and facilitated ankylosis of the digit when there is foot rot (interdigital necrobacillosis)--> when is this method indicated? what is the aim of this technique?This method is indicated if the owner wants to keep the animal in the herd. Usually indicated with coffin joint infection, infection that involves the flexor tendons and navicular bursa *The aim is to have an animal with 2 intact claws that can stay in the herd
describe the technique for Facilitated Ankylosis in cases of foot rotLateral restraint (involved limb up) - xylazine sedation. Local intravenous anesthesia (Bair regional block). Clean and trim the foot+ remove all necrotic tissue. Give 2 G Ampicillin through the same catheter that was used for the Bair block. Make an extensive longitudinal incision through the bulb of the heel extending from the sole to the proximal aspect of the bulb of the heel (just distal to the dewclaw) Remove the deep digital flexor tendon from the navicular bone and amputate it at the most proximal aspect of the incision. Use a bone chisel to cut the navicular bone in half and bone rongeurs to remove the navicular bone. Use a curette to remove the cartilage from the coffin joint. Massage the flexor tendon sheath proximal to the fetlock--> If there is pus, Identify the branch that supplies the affected digit and cut down to it proximal to the flexor retinaculum--> Pull the tendon proximally through the flexor retinaculum without incising the flexor retinaculum--> Amputate the tendon at the bifurcation--> Remove all the infected tendon sheath that is possible (proximal to the flexor retinaculum). THEN, Make Methyl methacrylate - naxel beads approx 1" in diameter and stick them to heavy vetafil suture: Insert the beads in the joint--> Remove the tourniquet, ligate significant bleeders, apply a heavy wrap and cast to just distal to the carpus or hock. Abx 2wk.Sedate & restrain the animal and remove the cast and methyl methacrylate beads at 3 weeks--> Rebandage and apply a 2nd cast. Remove the 2nd cast after 5 weeks
3 main ways you can help prevent foot rot?Attention to areas of lots or pastures in which animals can damage their feet. Foot baths containing dilute formalin or copper sulfate have been used. Give Zinc Supplement. Vaccine= Fusoguard (Novartis.) Some value in foot rot & liver abscesses
Interdigital fibroma "corns"--> what is this? Etiology?Don’t Confuse With Equine Corns!! not the same thing! it is a Hyperplasia of skin in the interdigital space (Pseudotumerous Fibrous Mass),which Becomes Painful in Time (etiology: A greater problem in large heavy cows and beef bulls, More frequent in some family lines)
how do you surgically remove the Interdigital fibroma/"corns"?Intravenous anesthesia or regional anesthesia... Remove an inverted V shaped segment of skin on the dorsal surface of the foot including the entire mass of involved tissue. Continue the incision on the axial side of each claw taking special care not to remove the coronary band. (Removal of the fat pad in the interdigital space is optional, it Delays healing, but Zebu cattle - respond better if the fat pad is removed even though healing is delayed) Suture the skin on the dorsal surface (proximal incision) - area between the claws is left to heal by second intention. Then bandage foot, wire claws together, Change bandage in 3 to 5 days. Leave the claws wired together until the wire wears and breaks

Hoof cracks and P3 fx

Question Answer
(not in powerpoint!!) there are type I through V hoof wall cracks-- briefly describe themtype I - confined to the coronary band and are usually associated with trauma. Type II - run from the coronary band to the center of the dorsal hoof wall. type III - run the entire length of the dorsal hoof wall. type IV - rare - run from the center of the wall to the bearing surface. type V - only involve the central region of the claw
with Vertical Hoof Cracks, sometimes they are not lame. but if they ARE lame, what should you do to tx?Trim out Crack (dremmel tool)--> Lace With Wire--> Stabalize with Acrylic. Don’t Put Acrylic Over Diseased Tissue (might have to put drain tube (fenestrated) deep to epoxy closure (base of crack) if soft tissue involved-- flushed periodically. )
what are horizontal hoof cracks usually associated with?Usually associated with drastic changes in feeding or a high fever (ie Laminitis or High Temperature).
is it vertical or horizontal hoof cracks which can involve several or all claws, and why?horizontal, because these are often due to more systemic problems (laminitis, fever)
how does a horizontal hoof crack affect the hoof?A horizontal crack that starts at the coronary band and over time progresses to the bearing surface of the hoof wall---> When the crack gets close to the bearing surface it sometimes becomes somewhat loose and pinches the lamina causing significant pain
how do you tx a horizontal hoof crack?Allow the crack to progress to the bearing surface. If there is pain then the segment below the crack should be removed
If you see a cow standing like this, what do you think is going on? prolly has fx 3rd medial phalanx if standing like this- crosses legs to put pressure on lateral 3rd phalanx instead of medial so it doesnt hurt as much (commonly occurs, not only reason for cows to stand this way tho)
clinical signs of a P3 fracture?Acute lameness, severe pain, No significant swelling, Animals with a fracture involving the medial claw will sometimes stand with crossed legs
should you take rads to confirm P3 fx?Radiographic confirmation is usually not necessary (however, Best done with a lateral or medial radiograph using mammography film placed between the digits)
how do you tx a P3 fx?Application of a wood block to the sound claw with hoof acrylic. Wire the fractured claw to the wooden block with the fractured digit slightly flexed. Keep the animal in a stall (if possible) for 8 weeks

not foot

Question Answer
etiology of long bone fx?Usually a result of external trauma... Bulls suffer from stifle problems and tibial fractures as a result of fighting during breeding (One bull mounts a cow and another competing bull runs into him from the side)
what determines whether or not you want to tx a long bone fx?animal must be able to stand on three legs! Don't attempt anything but salvage or euthanasia if the animal can't stand!! Furthermore, Salvage can only be done by home slaughter or at a location where they package game (deer, elk etc.), not at an inspected plant
is it easier to have a horse or a cow as a fx pt?Cattle are much better fracture patients than are horses--> They don't tend to panic and self destruct, They produce extensive callus, They protect the involved limb. Because of their thicker skin extensive cast sores are a lesser problem
how do you tx fractures of the lower leg (below carpus and tarsus)?Suggested routine is to cast fractures of the lower leg (below carpus and tarsus) with a full limb cast
how do you tx Fractures of the radius and tibia?splint immobilization
how do you tx Fractures of the femur and humerus?stall rest
what is a Walker Splint? when do you use it?usu used for Distal Femur, Stifle or Proximal Tibia (rear limbs). Usu considered if an expensive animal. There is A ring in the inguinal region, 2 adjustable bars on the medial side of the limb, and A distal foot plate to which the hoof wall is attached
if there are stifle injuries, what can you do to tx?Rest, Modified Schroder-Thomas splint (aka WALKER splint)
If you see a cow doing this, what do you suspect the problem is? UPWARD FIXATION OF THE PATELLA
why would you maybe see this weird wearing pattern on the claws? upward fixation of patella causes them to drag the toe on the ground--> odd wearing pattern
(long notes) breed disposition of upward fixation of the patella?Bos indicus breeds thought to be at greater risk
how does upward fixation of the patella present?Straight rear limb-- Catching in the gait just after full extension of the rear leg. Sometimes complete locking of the patella dorsal to the medial femoral condyle--> Animal will drag the involved limb and wear the toe excessively
how do you want the animal to be positioned to ID the ligament which is the problem in upward fixation of the patella?Weight Bearing
how do you sx tx upward fixation of the patella? (what procedure is very successful? how do you perform it? unilateral or bilateral sx?)Medial patellar desmotomy is 95% effective! Procedure performed as in the horse with the animal either restrained in a squeeze chute or in lateral recumbency with the involved leg down. Locate junction of medial and middle patellar ligaments! Best to perform the procedure on both rear legs!! This is bc If one leg is done quite frequently the animal develops the problem in the other in a short time.