Canine hip dysplasia diagnosis and treatment (Proceedings)
The diagnosis of hip dysplasia is commonly practiced but in my opinion is frequently misunderstood. First, one must determine and separate if the patient has clinical disease and or radiographic disease. Clinical disease must be determined using a physical exam and patient history and is mostly dependant upon finding pain while extending the hip joints. A positive Ortoloni sign, while useful information when establishing that a dog has abnormal hips, does not mean that the patient is clinically affected by the hip laxity. Radiographic disease can be simply summarized at the presence of hip laxity and or idiopathic hip osteoarthritis. Several radiographic techniques have been described and the merits of each will be discussed but in the speakers opinion the current science supports the use of the PennHIP method.
The treatment for dogs with canine hip dysplasia (CHD) included nonsurgical management, femoral head and neck excision (FHO), triple pelvic osteotomy (TPO), total hip replacement (THR) and pubic symphysiodesis (PS). Many other treatments have been mentioned in various reports but have not faired well when objectively evaluated. These include pectineal myectomy, BOP/Shelf arthroplasty, varus or derotational osteotomy, femoral neck lengthening, sacroiliac wedge rotation, and darthroplasty.
Prior to recommending surgical management for any condition it is important to understand and communicate to the owner the likely outcome with non-surgical management. Non-steroidal anti-inflammatory medications such as Deracoxib, Rimadyl, Etogesic and Ascriptin should provide some relief for the inflammation of the hip joint associated with CHD. Rimadyl and etogesic are FDA approved for pain and inflammation associated with arthritis in dogs. Recently, cyclooxygenase II specific inhibitors have been reported on in the dog for acute perioperative pain and chronic arthritis. Clinicians should not expect COX-II specific inhibitors to provide greater, although some publications suggest this to be true, relief but it can be expected that patients that use them will have fewer clinically relevant side effects. Finally, it should be noted that naproxen (Aleve) has a 7-day half-life in the dog and should be avoided.Glycosaminoglycans such as Adequan and Cosequin have been classified as joint modulating drugs. Lust et al. published that in skeletally immature Labradors predisposed to CHD Adequan provided some protection to the hip joint biochemically. In a clinical paper in dogs with established arthritis, however, de Haan found no treatment effect. Empirically, I have had little success using these medications.
Physical therapies such as swimming and daily leash walks are an important for maintenance of hip joint range of motion and limiting periarticular fibrosis. In a recent paper, however, it is important to note that range of motion during swimming was not greater in the hip joint when compared to range of motion during a walk or trot. This was different than other joints evaluated. Perhaps the greatest benefit to physical therapy is the caloric requirement necessary to perform the activity. Several recent papers have described that thin dogs perform better than overweight dogs and overweight dogs that lose weight (reduction in body condition score) have improved limb function. Obviously, dietary management must compliment this.
Two peer-reviewed publications address the outcome in patients with CHD that were treated with nonsurgical management. The likelihood of satisfactory pet function is reported to be between 80-85%.
Femoral head and neck excision is inexpensive and technically simple. Dogs that have FHO do have a loss of limb length that might contribute to lameness. They also have limited function, reduced ROM, and unsatisfactory results can be worse than pre-op function. The likelihood of success is not reported but when normal Greyhounds had FHO performed they had only 75% of normal limb function 4-months after surgery. Many surgeons perform muscle flaps (biceps, semitendinosis, deep gluteal) with FHO with some manuscripts reporting that they do better and some reporting that dogs do worse with muscle flaps. Finally, most surgeons are reluctant to revise a failed FHO or to perform THR after FHO. In a case series of 3 cases dogs that had THR after failed FHO did well.