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IN THIS NEWSLETTER:

The Ehmer
Sling

Doxycycline

Elbow Dysplasia

Open Fractures


Map of Our Location

Overview of Services

Information for Professionals

Online Resources

Home Page

Contact Us

 
Newsletter, 2001 Vol. 7, Issue 4

Open Fractures

Open fractures, previously termed compound fractures, are defined as those fractures in which bone is exposed through the skin to the external environment.  These fractures should be considered contaminated upon presentation, with a possibility of becoming infected if not handled properly.  This brief outline discusses practical management of open fractures.

There are 3 classification types of open fractures, as follows:
 

  • Type I Low energy.  The bone has penetrated the skin from the inside to the outside.  The wound is small and the bone may not be visible (retracts beneath skin surface).

  •  
  • Type II An external force penetrates the skin, communicating with the fracture from the outside to the inside.  Usually minimal loss of soft tissue and bone. Example = bite wound; low velocity gunshot.

  •  
  • Type III High energy external force communicates with the fracture from the outside to the inside.  May be extensive loss of soft tissue and bone.  Example = high-velocity gunshot.


These classifications have been simplified to a degree for clarity and to make it easier to remember when discussing with colleagues the severity of an injury.  For our purposes, they will serve to help us better manage the case involving these type fractures so that our chance of successful repair and an uncomplicated repair is enhanced.  The more severe the fracture, the greater the chance of infection and therefore the more important initial management of the fracture becomes!

When contacted by an owner who describes an open fracture, initial management instructions for the wound can be given to minimize further contamination before the animal is able to be transported.  The most important point to remember with any of the open fractures, regardless of classification, is that wound management and patient management are more important than fracture fixation in the initial period.  Contrary to some current teaching, none of these fractures (or more precisely very, very few) is a surgical emergency.  The over-all condition of the patient is the emergency.

The owner should be instructed to cover the wound and prevent further contamination while transporting the case to the veterinary hospital.  A clean cloth, disposable diaper or similar material can be utilized.

Once the animal arrives at the veterinary hospital, overall patient condition assessment is important before evaluating the fracture, as we tend to be distracted by the obvious injury and overlook potentially life-threatening internal injuries.  Particularly with gunshot wounds, the animal must be fully evaluated for the presence of internal injuries, neurological damage, and other gunshot wounds which may have been undetected.  If the animal is in shock or otherwise unstable, sedation must be used very cautiously, if at all, in the initial period when evaluating the fracture.

Many times these injuries present at night, and minimal help is available during the initial management of the fracture, which I realize.  Although all of the cases require antibiotic therapy, and intravenous antibiotic administration is preferable via IV catheter, that is sometimes not possible.  My preference is to use IV cefazolin (20 mg/kg q 8 hr) initially along with IV fluids.  Alternatively, if an IV catheter cannot be placed or IV drugs administered for whatever reason, IM amoxicillin and a fluoroquinolone may be used for broad-spectrum coverage.

Prevention of infection not only involves antibiotic therapy, but local wound management.  The first line of defense against infection is local wound management via extensive lavage of the fracture site.  I prefer to use a 1:40 solution of Nolvasan (mix 12.5 ccís Nolvasan solution in 500 mlís sterile water).  Most cases require at least one liter of flush (grade II and IIIís).  In an emergency where Nolvasan or other isotonic flush is not available, tap water can and should be used.  Grade I fractures may require minimal or no flush and probably do not require surgical debridement.  Some grade IIís and many grade IIIís may need surgical debridement upon presentation, or as soon as the animal is stable.  Common sense should be used in anesthetizing and operating on a compromised patient.  If in doubt, manage the wound with extensive lavage and a sterile bandage and wait until the animal is stable, rather than risking a life-threatening anesthetic episode to debride a wound.

Surgical fixation of the fracture is done when the animal is stable.

This brief presentation in no way covers every situation.  I have attempted to offer my experience with initial management of these wounds over several years as guidelines.  Each case presents an individual set of problems and should be handled accordingly.  Please contact me if you have any questions at any time regarding these injuries.
 
 
 
Newsletter, 2001 Vol. 7, Issue 3

Elbow Dysplasia

Elbow dysplasia: simply put, the elbow joint does not fit together properly, resulting in lameness, pain, and development of osteoarthritis.

The elbow joint consists of the humeroulnar articulation, the humeroradial articulation and the radioulnar articulation.  Elbow dysplasia results from incongruent articulation between any or several of these joint surfaces.  Also included in descriptions of elbow dysplasia are Ununited Anconeal Process (UAP), Osteochondritis Dissecans (OCD), and Fragmented Medial Coronoid Process (FCP).  In-depth descriptions of these conditions, their diagnosis and treatment can be found in numerous texts and articles in the literature.

Diagnosis of elbow dysplasia is made by physical examination and by careful radiography of the elbow joint.  Special radiographic positioning of the joint may aid in diagnosis, especially  UAP and FCP.  Accurate diagnosis can be complicated by the superimposition of one bone over another in both the lateral and craniocaudal views of this joint.

In all cases, a lateral view and a flexed lateral view of the elbow joint should be taken along with a craniocaudal projection of the joint. Fragmented coronoid may be visualized occasionally by taking a 25º craniocaudal-lateromedial oblique view of the joint.  This is obtained by rotating the elbow laterally 25º from the craniocaudal view.  Ununited anconeal process is diagnosed on the flexed lateral view of the joint; this view also allows visualization and inspection of the dorsal edge of the anconeal process - osteophyte formation here is noted as one of the earliest indications of a fragmented coronoid (FCP).

The lateral and medial humeral condyles should be closely evaluated and the cranial, medial, and lateral rim of the radial articular surfaces inspected.  On a craniocaudal projection, the lateral and medial humeral articular surfaces should be inspected closely for either primary OCD, or a wear-type or ďkissingĒ lesion secondary to chronic abrasion and abnormal articulation in the dysplastic joint.  Kissing lesions are frequently associated with concurrent FCP.

Early surgical intervention is advisable once diagnosis of elbow dysplasia is made.  Removal or reattachment of the anconeal process is done with UAP.  Fragmented medial coronoid is also handled by surgical excision of the coronoid process.  OCD of the elbow joint is a surgical condition, many times developing on the medial humeral condyle opposite a FCP.  Incongruence of the joint surfaces alone, without concurrent UAP, FCP or OCD, presents a treatment challenge.  Currently, there are ongoing studies to determine whether dynamic ulnar osteotomy is beneficial in improving the range of motion and congruence of these joints.

We are seeing with increased frequency dogs presenting as middle-aged to older with an acute onset of lameness and severe radiographic DJD in the elbow joint(s).  Many times, no prior  history of lameness, either as a juvenile or young adult, is noted.  The exact reason these dogs become suddenly lame is unknown.  Response to medical treatment may be unsatisfactory, and many respond poorly to Rimadyl and other NSAIDís.  The role of surgery in these joints is unclear.

Early diagnosis and surgery is most appropriate with elbow dysplasia.  The opposite, or unaffected, leg should always be imaged either as a normal control, or to screen for bilateral disease.  Results with surgical intervention are less than ideal once the elbow develops severe DJD.
 
 
 
Newsletter, 2001 Vol. 7, Issue 2

Doxycycline: A Potential Role in Osteoarthritis Modulation?

Osteoarthritis (OA) is a common and debilitating orthopedic disease of dogs and humans.  While all of the mechanisms of OA induction are not fully known, in general, there is loss of cartilage homeostasis and a disruption in the balance between chondrocyte anabolic and catabolic processes.  The end result is a breakdown in the structural matrix of the articular cartilage, leading to the clinical signs of arthritis. 

Some of the substances implicated in this cartilage destruction are inflammatory cytokines, of which interleukin-1 and tumor necrosis factor-alpha are involved.  Also, stimulated synthesis of matrix metalloproteinases (MMPís) is responsible for cartilage destruction.

Doxycycline is a semi-synthetic tetracycline antibiotic which has been shown in vitro to have significant inhibition of collagenases and gelatinases.  There is good experimental evidence available to support the disease-modifying and chondroprotective effects of doxycycline, independent of itís antimicrobial activity.  The use of doxycycline clinically to modulate the effect of osteoarthritis (OA), is currently the subject of numerous scientific studies.  It appears from at least the initial studies in cranial cruciate deficient stifle joints, that doxycycline can modulate the synthesis of prostaglandins and intra-articular nitiric oxide, which are produced by the inflammatory cytokines and act to sustain the progression of osteoarthritis (OA).

The optimum dose of doxycycline to use for modulation and inhibition of OA is not know.  Experimentally, one study using a dose of 3-4 mg/kg once daily was successful in modulating OA progression.  Whether the same effect can be achieved using low-dose doxycycline is not known.  Low-dose doxycycline use has been advocated as one method of preventing the development of bacterial resistance to doxycycline.  Conversely, higher doses of doxycycline may be needed to inhibit other enzymes associated with OA (i.e. stromelysin).  Also, the combination of doxycycline and one of the newer non-steroidal anti-inflammatories (NSAIDís) may have synergistic effects on OA inhibition.

Clinical studies on the use of doxycycline and other chemically modified tetracyclines are ongoing.  Do not be surprised in the future to see a recommendation for treatment of osteoarthritis with an antibiotic!

REMINDER

We are happy to provide radiographic consultation on cases.  There is a charge for this service and you should contact our office prior to sending radiographs.  If you would like the films returned via mail, a pre-paid mailer should be included.
 

 NEWS

Many of you will recognize a familiar voice answering the phone.  Melissa Dugan (Mo) has rejoined the practice and is again available to assist you and your clients.  Please join us in welcoming Mo back!
 
 
 
Newsletter, 2001 Vol. 7, Issue 1

BACK TO THE BASICS: THE EHMER SLING

The Ehmer, or figure-of-eight sling, is one of the most useful and easily applied bandages in Veterinary Medicine.  Properly applied, it maintains the pelvic limb flexed, with the hip joint abducted and internally rotated.

The primary use of this sling is to maintain the hip joint in a stable position following closed reduction of craniodorsal hip luxation.  Maintenance of the hip joint inwardly rotated and abducted provides maximal coverage of the femoral head within the acetabulum, enhancing success of closed hip reductions.  The Ehmer sling may also be of benefit in maintaining hip stability in the immediate postoperative period following certain surgical procedures such as femoral head & neck fracture repair, acetabular fracture repair, and to provide additional stability following open hip luxation correction.  A slight variation of the Ehmer sling is the 90:90 flexion bandage, useful when internal rotation and abduction is not required.

The only material necessary for application of the Ehmer sling is a roll of elastic tape such as Elastikon® or Conform®.  Absent elastic tape, white porous tape in 1", 2" or 4" width may be used depending on the size of the animal.  I do not use cast padding or gauze under the tape, as it tends to slip and be less secure than using tape alone.

To begin application of the Ehmer sling, tape is first anchored to the metatarsal region of the foot, wrapping it loosely around the metatarsals.  Taping is begun on the dorsal metatarsus, proceeds to the lateral and then the plantar surface of the metatarsus.  Two or three loose wraps should be taken.  The tape is then directed up the medial aspect of the tibia with the limb flexed, proceeding along the medial surface of the stifle and thigh musculature (A).  After the tape is passed medial to the thigh muscles, it is brought over the top, or cranial aspect of the quadriceps femoris group of muscles, to the lateral side of the thigh to continue distally caudal to the stifle joint.  The tape then passes medial to the tibia and then down the distal aspect of the tibia to the level of the medial hock (twist 180° to keep adhesive surface adjacent to metatarsus), where it is passed along the plantar surface of the metatarsals from medial to lateral (B & C).  The procedure is then repeated two to three times, attempting to place the tape as high in the groin region at the top of the wrap as possible to prevent it from slipping off the cranial aspect of the thigh.  When properly applied, the toes will point slightly inward, the hock will be rotated externally, and the stifle and coxofemoral joint will be rotated internally.  To provide maximal coverage of the femoral head within the acetabulum, abduction of the limb is achieved by passing a length of tape from the plantar metatarsus, over the lateral aspect of the flexed limb, and around attaching it to a pre-placed tape belly band (D).

A properly applied Ehmer sling is well-tolerated by most dogs.  I prefer to leave it in place for 2 to 3 weeks, depending on the condition it is used for.  I do not immobilize joints longer than 3 weeks.  Owners are advised to monitor the bandage and especially the toes for swelling - if the toes or distal limb starts to swell, the bandage must be removed immediately.  Owners are also advised that irritation of the skin in the groin region will occur, and is managed conservatively following sling removal.