Q: My 8 year old Sheltie suddenly became lame on one of her rear legs. My vet took x-rays but said there was no arthritis or fractures. What else could be wrong?
A: Most lameness conditions, other than fractures, cannot be diagnosed through an x-ray. A lameness of the leg could indicate a problem stemming anywhere from the back to the paw. Slipped discs or other spinal conditions can impinge on the nerve that innervates the leg and create a lameness. Other conditions can include diseases of the joints such as Lyme disease, torn or slipped ligaments and medial or lateral patellar luxation (i.e. trick knee). Simple things such as splinters, lacerations, sap or small stones in the paw can also create lamenesses. Other times, it may be a sprain or sore muscle that require time and rest to heal. Overall a thorough examination of the leg is required to best determine the condition and the appropriate treatment.