Orthopedic exam and bandaging (Proceedings)

Use a systematic approach to ensure that you do not miss any problems. In general I use an eight step approach to the orthopedic examination:

1) Signalment – age, gender, breed. This information can help you narrow your differential diagnosis list, by excluding certain diagnosis that only occur in animals of a certain age range or breed. It should also help you to weight certain diagnoses, moving them higher or lower on your list of differentials.

2) History – includes when problem started, owner identification of involved limb, problem progression (is it getting worse, better or staying the same over time), efficacy of previous and/or current treatments, variations in the problem (lameness) and presence of any systemic illness. A problem like osteoarthritis is usually worse when the animal first arises and then improves with moderate activity. With a muscle, tendon or ligament problem, the animal is usually fine at the beginning of an activity and becomes progressively more lame and may eventually just quit.

Also be attuned to unusual presentations, such as the older animal that suddenly becomes non-weight bearing while walking or going down stairs. If a fracture is found, be suspicious of a pathological process, i.e. osteosarcoma, causing the fracture. A chronic disease such as coxofemoral osteoarthritis secondary to canine hip dysplasia or patellar luxation does not cause an acute non-weight bearing lameness. Think about other causes of the lameness such as an acute hip luxation, a fracture or a cranial cruciate ligament rupture.

Also, orthopedic problems will almost never cause an animal to drag its toes and cause nail wear. If you hear about this, be thinking about a neurological problem. Don't ignore other limbs just because you've been told that the presenting complaint is in a specific limb. For example, I recently saw a puppy that was brought in for a right thoracic limb problem and the dog indeed had a growth abnormality in the right antebrachium. But the dog was limping off of the left thoracic limb and I diagnosed a left fragmented coronoid process!

3) Gait Evaluation – Look at how the animal stands, sits, and rises. Look for general conformation, limb symmetry, joint alignment, weight shifting. A dog with cranial cruciate ligament disease will not sit with the affected limb flexed beneath it (positive sit test).

First the gait at a walk, looking for shortened stride length, abnormal joint movement, head bobbing, shifting of body weight and ataxia or nail scuffing. Head bobs occur with thoracic limb problems and the dog's head will go down when weight is placed on the sound limb and come back up when weight is placed on the lame limb as the dog tries to decrease the weight born on the affected leg. A swinging, circumduction of the thoracic limb is associated with infraspinatus tendon contracture. A dog with palmar laxity or carpal hyperextension injury will stand and walk with the more than normal extension in the radiocarpal joint (palmigrade).

If a joint is painful for the dog, they will usually limit the range of motion of that joint during the gait cycle. A dog with hip dysplasia or secondary arthritis is painful during hip extension and will not fully extend its legs even at faster gaits. It is painful for a dog with cranial cruiate ligament disease to flex its affected stifle and will keep it's stifle somewhat extended during the gait cycle. A dog with patellar luxation is not usually lame until the patella luxates at which time it will kick or extend its leg behind itself until the patella is reduced.

4) Standing examination – Lameness is usually present because the animal is painful somewhere. Unfortunately in order to localize the problem/source of pain, we have to inflict pain. Most dogs will vocalize or try to pull away when you get to a painful spot, but they may try to bite. Once you know an area is painful, be gentle during further assessment. I also try to start with the normal, non-painful limbs so the animal is not expecting to be hurt every time you touch it.

Usually start with a brief, screening neurologic exam, palpating along the spine, moving the neck and lifting the tail. Check for conscious proprioceptive deficits if nail scuffing or wear seen during gait evaluation. Palpate both thoracic limbs, then both pelvic limbs simultaneously to compare muscle mass, joint distension, abnormal posture/conformation. It is easier to appreciate mild muscle loss or joint effusion when the other side is normal. You can often see joint effusion in the hock of dogs with an OCD lesion by looking and palpating from behind. A dog with a chronic cruciate ligament rupture will have thickened soft tissue on the medial aspect of the stifle, called a medial buttress, that can be felt and seen during the standing exam.

I will usually lift and palpate each limb individually wil the dog is standing. The dog may be unwilling or unable to support weight on the problem limb. I also check for cranial tibial thrust with a tibial compression test while the dog is standing.

5) Recumbent examination – This is done to fully assess every part of all limbs. You want to proceed in a systematic manner, so you don't forget anything. I usually start at the toes and work my way up. If the problem is a right thoracic limb lameness, I will start with the dog in right lateral recumbency and examine both left limbs and then turn the dog over and examine the right pelvic limb and finish with the affected limb.

Palpate the digits individually, check for broken nails, nail wear, interdigital draining tracts. Apply gentle pressure to the palmar aspect of the metacarpophalangeal joints to assess for thickening and pain associated with sesamoid fractures that are common in the 2nd and 7th sesamoids, especially in rottweilers.

Each joint should be checked for range of motion (ROM), joint effusion, joint capsule thickening, crepitation and laxity or instability (subluxation/luxation). You need to know approximate normal ROM for each joint (see table below), but you can also compare right to left and look for differences (as long as the problem is not bilateral). Joint effusion is a softer, fluctuant distension that may slightly limit ROM while joint capsule thickening is more firm and non-fluctuant and may severely limit ROM. Crepitation may be due to an intra-articular fracture, loss of cartilage (osteoarthritis), or from soft tissues skipping over bone spurs. Laxity or instability means an increase in the normal ROM and may be in the craniocaudal or mediolateral plane or both. Each joint needs be checked while trying to immobilize all other joints, so you can be more certain that any pain response is arising from the joint you are trying to check at that time. This can be very difficult.

The long bones should be palpated for irregular surfaces and local areas of pain. Pain, swelling and heat from the distal antebrachium or crus in a young dog may be indicative of hypertrophic osteodystrophy (HOD). Pain with pressure over the metaphysis of a long bone in a growing dog may be indicative of panosteitis, especially with the history of a shifting limb lameness.

6) Sedated examination – Used for dogs that are too tense to palpate or too fractious to handle and palpate awake. Although you will be able to check ROM and better appreciate any joint laxity, you will be less able to elicit a pain response to aid in localization. I have used a combination of acepromazine (0.05-0.1 mg/kg, max dose 1 mg) and butorphanol (0.1-0.2 mg/kg) given intravenously. Radiographs should be taken while still under the effects of the sedative.

7) Radiographic examination – Since radiographs are a relatively inexpensive and easy method of visualizing the skeletal system, we use radiography regularly for definitive diagnoses of orthopedic problems. Two orthogonal projections (90 degrees to each other, usually craniocaudal and mediolateral) are routinely taken. Additional specialized projections are valuable for certain problems such as a skyline view for differentiating between mineralization of the supraspinatus versus bicipital tendon and stress views for assessing joint laxity/subluxation. It is important to know what is normal versus abnormal in the skeleton.

8) Additional Diagnostic Tests

a. Arthrography – radiography after a contrast agent(s) have been injected into the joint. Can use a radioopaque material with or without air to define filling defects, i.e. OCD lesions, bicipital tenosynovitis lesions

b. Myelography – for neurologic cases to visualize the spinal cord for lesions, i.e. disk protrusion/extrusion, tumors

c. Computed tomography – serial cross sectional images of a region gives a more detailed image. Excellent for FCP lesions, spinal lesions in place of myelography.

d. Magnetic resonance imaging – uses a magnet to align and then disrupt the alignment of atoms. Excellent for cartilage and soft tissue lesions.

e. Nuclear medicine scans – uses radiopharmaceuticals (technetium) to visualize bone lesions. Accumulates in regions of inflammation and new bone formation. Take a very early image using the gamma camera, called the pool phase for inflammation and a later image after 90-120 minutes, called the bone phase, to see new bone formation (may be in response to inflammation, infection, fracture or neoplasia). I find it useful for dogs with an obvious thoracic limb lameness when I cannot elicit any pain and therefore cannot localize the lesion.

f. Ultrasonography – best for imaging muscles, tendons and ligaments. Need an experienced radiologist to make this worthwhile. I use it to image tendons in the shoulder and for iliopsoas muscle/tendon problems.

g. Kinetic/kinematic analysis – uses a force platform with or without cameras to measure how much force (weight in kg x gravity) a dog is placing on each limb. Can be broken down into three different vectors, vertical, craniocaudal and mediolateral. Gives an objective measure of a lameness. With cameras videotaping reflective markers on the limbs, motion analysis can be done to measure joint angles, joint velocity, joint acceleration and deceleration throughout a gait cycle.

h. Arthroscopy/arthrotomy – direct visualization of the interior of the joint with or without magnification. Allows diagnosis and treatment. More in the September 25th lecture, Introduction to Arthroscopy.

i. Arthrocentesis – aseptic collection of synovial fluid for gross and microscopic analysis and culture. Can help in diagnosing septic and immune mediated arthritides.

j. Blood work, titers, hormone profiles – can help to definitively diagnose orthopedic problems that are caused by systemic illness, i.e. Ehrlichia, Borrelia, hypothyroidism and SLE.

The typical compressive bandage used in orthopedics is the Robert Jones. To immobilize and stabilize a splint or anterior half case is commonly used. Other bandages one should be familiar with are the spica splint, Velpeau sling, Robinson sling and Ehmer sling. Perhaps the most important aspect to applying the bandage has to do with instructing the owner how to care for it. All patients that had a bandage applied should go home with a bandage care sheet the instructs the owners to call a veterinarian if the bandage changes in position (slips or rotates), develops an odor, becomes wet, or if the patient acts depressed or will not eat. In addition, all bandages should be checked every two weeks.