Canine elbow dysplasia- Part 2
Synovial fluid analysis
In patients where CED is suspected clinically but the available diagnostic imaging does not allow a definitive diagnosis, analysis of the synovial fluid via arthrocentesis is often consistent with low to moderate osteoarthritis and may be helpful to confirm clinical suspicions (2).
Advanced diagnostic imaging
Diagnostic use of CT for skeletal pathologies has recently become more accessible and popular (8). For CED, the multi-slice cross-sectional imaging of CT alleviates problems of superimposition, improving examination of tissue anatomy and architecture. CT has previously been used to help diagnose elbow dysplasia when radiographs did not provide a definitive diagnosis (19) and eliminated the false positive results obtained with survey radiographs in the detection of FCP. In fact CT has been reported to achieve the highest accuracy (86.7%) and sensitivity (88.3%) when compared to radiography, xeroradiography, linear tomography and positive contrast arthrography for FCP diagnosis (20). CT provides complete imaging of articular subchondral bone but not articular cartilage and therefore many subchondral bone changes associated with MCD and OCD, including sclerosis, fissures, necrosis, cysts, and fragmentations, are detectable (Figure 10). Furthermore, medial coronoid process abnormalities identified by CT include abnormal shape, distinct or separate fragments, fissures, or insitu fragments, and associated radial incisures irregularities or lucencies (8). This knowledge is invaluable when it comes to surgery. CT is the most widely used diagnostic technique to assess elbow incongruity but assessment is reportedly affected by positioning (8,11).
Definitive diagnosis of the type and severity of CED is obtained through arthroscopy. This technique enables observation of all articular structures of the joint and positive diagnosis of UAP, OCD, MCD and particularly cartilage disease (Figure 11). Note that cartilage lesions are not identified by CT, but are detected using probing on arthroscopic assessment (8). Cartilage disease may be graded using a modified Outterbridge scale (1,2). Arthroscopy has been compared with CT and radiology for assessment of EI and is reported to be superior to both techniques for diagnosis of this condition (21).
Treatment of elbow dysplasia is often a combination of medical and surgical management, and simple algorithms for both young dogs with CED and older dogs with OA secondary to CED are shown in Tables 1 and 2. The objectives of therapy are to relieve pain, maintain limb function, and slow the progression of OA. The specifics of surgical management are dependent upon diagnosis. Regardless of surgical technique, later development of osteoarthritis with varying degrees of functional impairment may be expected, and should be treated with a multi-modal approach including physical therapy, medications such as non-steroidal anti-inflammatory drugs (NSAIDs) and joint supplements, weight and exercise control, intraarticular injections and surgery.
The following will consider the surgical management of specific elbow conditions.
Based upon a combination of radiographic and intra-operative findings, a 3-stage classification of UAP in growing dogs has been proposed. This classification allows selection for the best surgical treatment (22) as follows:
• In group 1, where the AP is still firmly attached to the ulna with fibrocartilaginous tissue, oblique osteotomy of the proximal ulna is sufficient to restore joint alignment, relieve pressure on the AP and allow bony fusion with the proximal ulna (Figure 12); lag screw fixation of the AP should not be necessary but can be useful, particularly in active dogs.
• In group 2, where the AP is still attached to the ulna with some fibrocartilaginous tissue but is somewhat loose, proximal ulnar osteotomy is necessary to restore joint alignment and relieve pressure on the AP; lag screw fixation is mandatory to allow the AP to attain bony fusion with the proximal ulna (Figure 13).
• In group 3, where the AP is very loose, attached to the ulna only by the caudal ligament, the AP cannot be reduced to its original position because of the flattening of the ulnar bed, and proximal ulnar osteotomy is necessary to restore joint alignment. The AP is usually removed because the chance of achieving anatomically accurate apposition with bony fusion is unlikely (Figure 14).
In chronic cases removal of the AP may be indicated, although clinical improvement is often not achieved because of the severe osteoarthritic changes within the joint.
Young patients affected by medial compartment disease are suitable candidates for surgical treatment. Surgical removal of bony fragments (via arthroscopy or arthrotomy) is always recommended before severe arthritis develops, although older patients may also be treated surgically if a coronoid fracture is detected. Both techniques achieve a similar clinical outcome, but arthroscopy appears superior because a full joint examination can be performed. Unfortunately this disease is progressive and the prognosis is guarded: improvement is expected after surgery, but not a fully functional recovery. In order to improve the patient outcome other surgical techniques such as biceps ulnar release, subtotal coronoid osteotomy, ulnar osteotomy, sliding humeral osteotomy and osteochondral autograft transfer have all been suggested (3).
In patients affected by EI the aim of the surgery is to restore joint congruency by means of corrective osteotomies. Ulnar osteotomy or radial lengthening is particularly indicated in dogs affected by severe radio-ulnar incongruency (5).
Medical therapy for a patient affected by osteoarthritis consists mainly of NSAID’s use. At least two weeks’ therapy is recommended; treatment should be discontinued if the patient develops side effects. The authors recommend a week of rest followed by gradually increased physical activity. Systemic corticosteroids are avoided because of their potentially dangerous side effects. Administration of diet and dietary supplements, such as glucosamine and chondroitin sulphate may also play a role.
If response to the above is poor, an intra-articular treatment may be considered. The authors’ preferred procedure is based on joint flushing with sterile saline solution followed by intraarticular injection with hyaluronic acid; this is repeated three times with a 3-4 week period between each procedure. If the clinical outcome is still unsatisfactory intra-articular injections of methylprednisolone acetate or triamcinolone may be used. Side effects are usually minimal, although in some patients both local and systemic side effects have been reported.
In cases where medical therapy fails and both the medial and lateral compartments are severely diseased, with extensive loss of cartilage and subchondral bone eburnation, salvage procedures such as total elbow replacement or elbow arthrodesis may represent the only viable options for restoration of acceptable limb function. Whereas elbow arthrodesis may provide marked improvement for dogs with severe degenerative joint disease, substantial functional lameness inevitably persists with limb circumduction and potential associated disability. Total elbow replacement is widely considered to be preferable to arthrodesis; however, the high incidence of morbidity and prolonged convalescence associated with currently available implant and instrumentation systems are of concern. Novel implant systems may lessen these concerns but long-term clinical outcome data is not yet available (3).
CED is a complex condition of major importance in many medium and large breed dogs; careful assessment of an affected animal and identification of individual components of the syndrome will enable optimal selection of treatment techniques, but owners should be alerted to the likelihood of secondary osteoarthritis and the need for possible long-term therapy.
This article was kindly provided by Royal Canin, makers of Mobility diet for dogs and cats. For the full range please visit www.RoyalCanin.co.uk or speak to your Veterinary Business Manager:
1. Robins G, Innes J. The elbow. In: Houlton JE, et al. eds. Manual of Canine and Feline Musculoskeletal Disorders. 1st ed. Gloucester: BSAVA, 2006;249-261.
2. Schulz KS, Krotscheck U. Canine Elbow Dysplasia. In: Slatter D, ed. Textbook of Small Animal Surgery. 3rd Ed. Philadelphia: PA, Saunders Elsevier, 2003;1927-1952.
3. Fitzpatrick N, Yeadon R. Working algorithm for treatment decision making for developmental disease of the medial compartment of the elbow in dogs. Vet Surg 2009; 38:285-300.
4. Danielson KC, Fitzpatrick N, Muir P, et al. Histomorphometry of fragmented medial coronoid process in dogs: a comparison of affected and normal coronoid processes. Vet Surg 2006;35:501-509.
5. Samoy Y, Van Ryssen B, Gielen I, et al. Review of the literature: elbow incongruity in the dog. Vet Comp Ortho Trauma 2006;19:1-8.
6. Guthrie S. Some radiographic and clinical aspects of ununited anconeal process. Vet Rec 1989;124:661-662.
7. Reichle JK, Park RD, Bahr AM. Computed tomographic findings of dogs with cubital joint lameness. Vet Rad Ultra 2000;41:125-130.
8. Cook CR, Cook JL. Diagnostic imaging of canine elbow dysplasia: a review. Vet Surg 2009;38:144-153.
9. De Rycke LM, Gielen IM, Van Bree H, et al. Computed tomography of the elbow joint in clinically normal dogs. Am J Vet Res 2002;63:1400-1407.
10. Mason DR, Schulz KS, Samii VF, et al. Sensitivity of radiographic evaluation of radio-ulnar incongruence in the dog in vitro. Vet Surg 2002;31:125-132.
11. Holsworth IG, Wisner ER, Scherrer WE, et al. Accuracy of computed tomographic evaluation of canine radio-ulnar incongruence in vitro. Vet Surg 2005;34:108-113.
12. Kramer A, Holsworth IG, Wisner ER, et al. Computed tomographic evaluation of canine radioulnar incongruence in vivo. Vet Surg 2006;35:24-9.
13. Hornof WJ, Wind AP, Wallack ST, et al. Canine elbow dysplasia: the early radiographic detection of fragmentation of the coronoid process. Vet Clin North Am Small Anim Pract 2000;30:257-266.
14. Wosar MA, et al. Radiographic evaluation of elbow joints before and after surgery in dogs with possible fragmented medial coronoid process. J Am Vet Med Assoc 1999;214:52-58.
15. Meyer-Lindenberg A, Fehr M, Nolte I. Co-existence of ununited anconeal process and fragmented medial coronoid process of the ulna in the dog. J Small Anim Pract 2006;47:61-65.
16. Blond L, Dupuis J, Beauregard G, et al. Sensitivity and specificity of radiographic detection of canine elbow incongruence in an in vitro model. Vet Rad Ultra 2005;46:210-216.
17. Gemmill TJ, Clements DN. Fragmented coronoid process in the dog: is there a role for incongruency? J Small Anim Pract 2007;48:361-368.
18. Wisner ER, Pollard RE. Orthopedic diseases of young and growing dogs and cats. In: Thrall DE, ed. Textbook of Veterinary Diagnostic Radiology. 5th ed. St. Louis: Saunders Elsevier, 2007;268-283.
19. Rovesti GL, Biasibetti M, Schumacher A, et al. The use of computed tomography in the diagnostic protocol of the elbow in the dog: 24 joints. Vet Comp Ortho Trauma 2002;15:35-43.
20. Carpenter L, Schwarz P, Lowry J, et al. Comparison of radiologic imaging techniques for diagnosis of fragmented medial coronoid process of the cubital joint in dogs. J Am Vet Med Assoc 1993;203:78-83.
21. Wagner K, Griffon DJ, Thomas MW, et al. Radiographic, computed tomographic, and arthroscopic evaluation of experimental radio-ulnar incongruence in the dog. Vet Surg 2007;36:691-698.
22. Vezzoni A: Dynamic ulna osteotomies in canine elbow dysplasia, in Proceedings. 27th WSAVA 2002. Available at: www.vin.com/proceedings/Proceedings.plx?CID=WSAVA2002&PID=2668
This article was previously published in 2012.