HIND LIMB LAMENESS IN DOGS: A VETERINARY SURGEON’S PERSPECTIVE Paul Freeman MA VetMB CertSAO MRCVS The Veterinary Practice Millennium Way Braintree Essex CM7 3GX Introduction The following article includes an account of how I perform an investigation into hind limb lameness in dogs; it is not intended to be a definitive guide, but should provide an insight into the examinations and methods which can be utilised to arrive at a diagnosis. Any discussion of the causes and treatments of hind limb lameness is greatly assisted by an understanding of the range of problems seen in different ages and breeds of dog. The old adage that “common things are common” should always be kept in mind, and the article provides a list of the more common conditions, although this is not intended to be exhaustive. Finally I have provided a brief overview of my current thoughts on one of the more common causes of hind limb lameness, cranial cruciate ligament disease. The Lameness Investigation In making a diagnosis of the cause of lameness, I always like to begin with a careful history taking. This need not take very long, but requires the ability to listen and extract the useful information from the dog’s owner. Owners often become side-tracked when discussing their dog’s problem, and sometimes will have decided what is wrong (or what cannot possibly be wrong), before seeking assistance. Apart from ascertaining the age and breeding history, the important things are whether the lameness is acute or chronic, whether there was a known incident that precipitated the problem, whether it is progressive or static, and whether it is improved or exacerbated by rest and/or exercise. The next step is to assess the dog moving; it is very common to be presented with a dog for lameness
examination of the wrong leg! I always like to see the dog moving outside of the surgery at trot and walk; even when the problem appears severe and obvious, other things may be observed such as the existence of bilateral disease or a neurological problem. Once it is clear which leg(s) is/are affected, a thorough physical examination should be performed. A systematic approach should always be taken in order to minimize the risk of missing an important feature. I prefer to start with the foot and move proximally, except where I am very suspicious the problem is located in the foot, in which case I will begin proximally and leave the painful region till last. During the physical examination, it is important not to over interpret signs of pain or discomfort. Some dogs can be very fidgety, especially when handling their feet, and I always try to compare response to a similar examination of the contralateral limb. Once the painful region has been established, I also like to check that the response is repeatable. The physical examination is vital, since multiple pathologies may be revealed by radiographs; it is particularly important to establish the location of the problem when surgical treatment may be proposed. As well as a pain reaction, palpation may reveal joint swelling, muscle wastage or the presence of an abnormal mass, all of which may be significant. Once the location of the lameness has been established, further investigations may be proposed, including initially radiography and perhaps arthrocentesis. Radiography is still the main-stay of orthopaedic investigation, and good quality radiographs centred on the affected area are vital. Poor radiographs may suggest non-existent pathology
or miss the presence of subtle changes, and are a frequent cause of non diagnosis. Arthrocentesis is a relatively simple and minimally invasive technique which can normally be performed under sedation, and forms part of any examination into joint pathology (1). Samples of joint fluid can be taken from almost any joint, particularly if the joint is inflamed; cytology of this fluid can be performed quickly in a practice laboratory, and can be a sensitive way of confirming the location of intra-articular pathology, as well as diagnosing inflammatory and septic arthritis. It is rare that further investigative techniques are required, but on occasions further imaging may be helpful. Computed Tomography (CT) scanning is especially useful in the diagnosis of elbow dysplasia in the fore limb; Magnetic Resonance Imaging (MRI) scanning is occasionally useful in diagnosing soft tissue tumours; and scintigraphy is a sensitive method for picking up subtle and difficult to detect lesions. More invasive techniques such as arthroscopy or even open arthrotomy are also sometimes necessary to reach a final diagnosis, particularly in cases of meniscal injury secondary to cruciate ligament disease. In cases of neurogical lameness such as lumbosacral disease and nerve tumours, MRI is probably the most accurate diagnostic method, but Electromyographic (EMG) changes may also be found which are highly suggestive of the source of the problem. Differential Diagnoses Once the source of lameness has been established, a knowledge of the differential diagnoses becomes very helpful, and will aid the application of the appropriate investigative
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