1. Referral. Kevin Haynes, DVM, DACVS Ketaki Karnik, DVM, MS, DACVR

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1 VCAWLAspecialty.com Kevin Haynes, DVM, DACVS Ketaki Karnik, DVM, MS, DACVR Bully, a 5-year-old American bulldog/pitbull mix presented to for evaluation of lameness in the left thoracic limb Referral Bully is a 5-year-old male neutered American bulldog/pitbull mix that presented to the emergency service at for a recent bite wound on the lip and a history of limping on the left thoracic limb for 2 to 3 months in duration. The lameness appeared worse to the owners in the last 2 to 3 weeks. He was bright and alert on presentation. He has a history of skin allergies and current medication included Benadryl 150mg BID and Tramadol 100mg as needed for pain. 1

2 His general physical exam was unremarkable separate from the bite wound and abrasions to the face. His orthopedic exam revealed a grade 2/4, weight bearing left thoracic limb lameness. He had significant pain on flexion of the left elbow and reduced range of motion of the left elbow. There was crepitus and marked periarticular thickening of the left elbow. There was mild discomfort on extension of both coxofemoral joints but otherwise the remainder of the orthopedic exam was unremarkable. 2. Radiography A craniocaudal, lateral, and flexed lateral radiographs were procured for interpretation. The patient was diagnosed with an ununited anconeal process and medial coronoid disease, possibly with a fragmented medial coronoid process. (Figures 1 and 2) Figure 1 Figure 1: Flexed lateral projection. There is a 3.0 mm gap between the anconeal process of the ulna and the olecranon (arrow). An ill-defined angular mineral opacity measuring 4.0 mm is superimposed over the region of medial coronoid process of the ulna (arrowhead). The medial coronoid process is ill-defined. Osteophytes are on the margins of the elbow joint. 2

3 Figure 2 Figure 2: Craniocaudal projection. Osteophytes are on the margins of the medial coronoid process of the ulna (arrow). 3. Computed Tomography (CT) CT was recommended to better evaluate and characterize the presence of fragmented medial coronoid process of the left ulna and to better evaluate elbow joint congruity. Since fragmented medial coronoid processes and ununited anconeal processes are often bilateral, the right elbow could also be imaged simultaneously. CT revealed either a fused left medial coronoid process fragment or a large osteophyte along the medial coronoid process. In addition, there was elbow joint incongruity (Figure 3). The right anconeal process was united and there was also evidence of medial coronoid disease. 3

4 Figure 3 Figure 3: Sagittal reformatted image. There is incomplete fusion of the anconeal process to the olecranon (white arrow). There is a fused medial coronoid fragment or a large osteophyte along the margin (arrowhead). There is elliptical narrowing of the humeroulnar joint (black arrow). 4. Diagnosis Ununited anconeal process of the left elbow Bilateral elbow degenerative joint disease Bilateral fragmented medial coronoid processes vs osteophyte formation Bilateral elbow joint incongruity 4

5 5. Treatment: Proposed Surgery (procedures pending) Arthroscopy of the left elbow to evaluate remaining cartilage health, remove medial coronoid process or fused osteophyte, and evaluate ununited anconeal process. A caudolateral arthrotomy is performed and the anconeal process is excised. Expected recovery is unremarkable and a custom support brace is placed post-operatively. 6. Discussion Ununited anconeal process is a subset of the larger disease known as canine Elbow Dysplasia. The cause of elbow dysplasia remains unknown but several theories have been discussed, including; defects in cartilage growth, trauma, genetics, exercise, diet and so on. Elbow dysplasia is most likely a combination of these theories leading to a growth disturbance between the radius and ulna. When the ulna grows too slowly in comparison to the radius, it leads to increased pressure on the anconeal process from the humeral condyle. This increased pressure leads to failure of the anconeal process to attach at its normal growth plate at maturity. Ununited anconeal process is a disease most commonly seen in German Shepherd Dogs but can be seen in any dog suffering from elbow dysplasia. The anconeal process normal growth plate closure is around 10 to 14 weeks in the average dog but 14 to 20 weeks in the German Shepherd Dog. This delayed closure may be one reason there is an increased incidence of this condition noted in German Shepherd Dogs. Many of these dogs present for lameness at 5 to 9 months of age, but some do not present until 4 to 6 years of age due to signs of lameness from osteoarthritis. Often elbow dysplasia is bilateral and can make lameness difficult to identify by owners due to both front legs being affected. 5

6 Unfortunately once the growth mismatch leads to cartilage damage a continuous cycle of inflammation and joint damage begins leading to pain, lameness, and progressive osteoarthritis. The goal of surgery depends on the severity of the disease. If the signs and changes are mild or the extent of disease is so severe that surgery may not provide much benefit, medical management may be recommended. Surgical options also depend on the severity of the disease. Arthroscopy is performed to assess the level of cartilage damage and joint incongruency. Surgical options that may be performed include procedures that correct the growth disturbance and removal or fixation of ununited anconeal process. Fixation with a lag screw or anti-rotational pins should only be attempted when the condition is caught early and minimal to no cartilage damage or osteoarthritis is present. Delayed fixation after osteoarthritis is present or sclerosis of the subchondral bone may lead to non-union and inflammation and joint damage. In the most severe cases, total elbow arthroplasty may be recommended. Outcome varies depending on the level of cartilage damage that has occurred at the time of treatment. Many dogs will improve with surgery but often arthritis present will continue to progress despite therapy. CT can be helpful to look for other abnormalities that occur with elbow dysplasia such as joint incongruity, degenerative changes, and medial coronoid disease. These additional abnormalities may change prognosis or surgical planning for the patient. References: Tobias K. Veterinary Surgery: Small Animal. Vol. One. Elsevier 2012;

7 Surgery Kevin Haynes, DVM Associate Veterinarian Dr. Kevin Haynes, DVM (Practice limited to Surgery) Dr. Kevin Haynes obtained his doctorate of veterinary medicine from Kansas State University in He completed a one year rotating internship at VCA South Shore Animal Hospital in South Weymouth, Massachusetts and then followed that year with working as an associate emergency clinician at a Specialty and Emergency hospital on Cape Cod, Massachusetts. Dr. Haynes decided to pursue a career as a specialtytrained small animal surgeon and completed specialty internships in Florida and at VCA Alameda East Animal Hospital in Denver, CO. He completed his residency at the University of Minnesota in July, Dr. Haynes specializes in soft tissue, orthopedics and neurosurgery. He has a special interest in orthopedic surgeries and the management and alleviation of pain caused by osteoarthritis and orthopedic diseases. 7

8 Diagnostic Imaging Ketaki Karnik, DVM, MS, DACVR Veterinary Specialist Dr. Ketaki Karnik received her DVM degree from the University of California Davis and went on to complete a small animal medicine and surgery internship at the. She then completed a three year residency in radiology at The Ohio State University where she also received her Master s degree. During her residency, she received the American College of Veterinary Radiology resident research award and was also awarded the OSU Hospital Service Award. 8