Logical diagnostic approach to canine orthopedics (Proceedings)


Logical diagnostic approach to canine orthopedics (Proceedings)

Aug 01, 2011

Canine Orthopedic Diagnostic Flow Chart
Orthopedic diseases in dogs account for ~22% of all small animal diagnoses, based on the Veterinary Medical Data Base. The canine orthopedic diagnostic flow chart presented here (Figure) is a useful tool for diagnosing orthopaedic diseases in dogs by guiding the clinician to the most likely and logical group of diagnoses. This diagnostic flow chart is designed for the examination room setting by being based on practical, readily available, and mostly objective parameters of history and signalment (has major trauma occurred?, age?, size?), along with observing which leg(s) exhibit lameness or deformity. When combined with a good orthopaedic examination, the subsequent "rule out" list of diagnoses should be very reasonable in both length and reliability. In many cases, a definitive diagnosis can be made. Ancillary examinations of radiographs and arthrocentesis, if needed, complete the necessary diagnostics for most cases and are readily available to practitioners. This diagnostic flow chart's reliability and usefulness has been validated by over 20 years of use by the author, and review of 177,435 orthopaedic cases out of 812,785 total dogs in the VMDB over a 20 year period. The number of cases, in the VMDB over this 20 years, for a disease are listed next to the disease in the flow chart. The VMDB data comes only from colleges and schools of Veterinary Medicine, so may not accurately indicate frequency of some orthopedic diseases in private practice, especially those that would not typically be referred (e.g. panosteitis).

Trauma is at the top of the algorithm because trauma happens to all dogs, regardless of signalment.

Trauma is an obvious etiology/diagnosis for most, but not all, cases. Major trauma is necessarily acute, and is accompanied by most or all of the cardinal signs of inflammation. If a dog has acute onset of orthopedic clinical signs and/or any of the cardinal signs of acute inflammation, then careful history should be taken to evaluate the potential for trauma. Examples are specifics of the dog's confinement; the dog's exposure to other dogs, livestock or children; work or athletic activities, etc..

If trauma has been eliminated as a likely etiology for the lameness (or other orthopedic signs), then the next question is age, which can be objectively answered for most dogs. Orthopedic diseases of dogs are readily separated into those of young dogs (< 18 months old), and those of mature dogs (> 18 months old). Age at onset of clinical signs is most appropriate, but not required.

Of the Mature and Geriatric diseases, all except degenerative joint disease (DJD) occur in dogs at a mean age of > 4 years old in > 80% of the cases. DJD has a mean age of > 4 years old in 75% of the cases. DJD is the most significant disease to be in more than one category with substantial frequency.

The Juvenile Bone and Joint Diseases (JBJD) category is named to include congenital, inherited, and developmental diseases. Many of these diseases are included because their etiology dictates the disease initiated in dogs < 18 months of age (e.g. osteochondritis, asynchronous growth of the radius and ulna, ectrodactyly). Others are well known to occur (at least initially) in juvenile dogs (hypertrophic osteodystrophy, panosteitis, fragmented coronoid process). The disease may be diagnosed well after 18 months of age, especially for lower morbidity conditions (e.g. patella luxation). JBJD's can be further divided into diseases of large breed or small breed dogs, another objective assessment with ~ 30 lbs being the dividing point. Hip dysplasia and patella luxations commonly occur in both large and small breed dogs, and are included in both categories. JBJD's can be further divided into conditions of the front leg or rear leg based on anatomy and correlated to the leg(s) which are lame or have other orthopedic signs.

Application Of This Orthopedic Diagnostic Flow Chart Should Result In A Very Logical And Short "Rule Out" List. If Orthopedic Examination Localizes The Pathology To One Anatomic Location, The Longest "Rule Out" List Is For The Elbow (Uap, Fcp, Ocd, Elbow Dysplasia). The Clinician Is Cautioned To Examine Every Leg On Every Dog, Every Time Because More Than One Orthopedic Condition In The Same Dog Is Common.