THE RELATIONSHIP BETWEEN SURGERY and osteoarthritis management has always been an interesting one. On one hand, surgery is an important tool in the modification and management of OA; on the other, surgery to a joint is likely to be followed by the development of OA, as a direct consequence of the damage already initiated by the condition that indicated the surgery.
Often this important link is forgotten, with the notion that surgical management of the primary problem is completely curative. Degenerative joint disease is then seen as a failure rather than an inevitable consequence of the problem.
A chance is missed to produce a better end-result by addressing and attempting to control the development of OA management during the surgical recovery period and beyond. But we need to know the real likelihood of this problem after joint surgeries to dismiss or address it.
Surgical intervention can play an important role in the management of osteoarthritis in dogs and cats. Surgery has most benefit in the early stage of the disease to try and modify development of the disease or in the late joint disease as an attempt to salvage and restore some pain-free function when non-surgical management is failing to control pain or the joint is mechanically non- functional.
We are probably much more familiar with salvage procedures in relation to OA while the long-term effect on the development of OA in early disease interventions is much more poorly appreciated.
Surgical intervention in early joint disease
Surgery can be used in the early stages of osteoarthritis to correct the problem that is damaging the joint and initiating degenerative disease. Used in this way it can limit the rate of development of degeneration by improving anatomy, reducing pain and helping to restore more normal joint function. Examples of this would include surgical stabilisation in cruciate disease or other traumatic ligament failures. It can also be used to influence or alter disease progression by altering the anatomy and/or weight-bearing focus in young growing dogs affected by dysplastic changes in one or more joints (Table 1).
The manner in which improvement is achieved in each of these techniques varies, with anatomical modification to either alter the stability or the weightbearing focus of the joint (Table 2).
Juvenile Pubic Symphysiodesis (JPS) achieves its effect by altering the way the pelvis develops through growth and changes the relationship between the acetabulum and the femoral head in a positive fashion to reduce instability and improve joint congruence.
We will now review some of these procedures, commenting on the key objectives of the surgery and the evidence available for long-term impact on joint disease.
1. Triple or Double Pelvic Osteotomy in hip dysplasia
The main objective in this surgery is to isolate the acetabular segment of the pelvis by using two or three strategic osteotomies in the ileal body, the ischium and the pubis (TPO). This allows the pelvic segment to be rotated laterally to increase the dorsal coverage of the femoral head by the dorsal rim of the acetabulum (Figure 1).
The osteotomised portion of bone is then stabilised using a special plate to allow early joint function while the bone is healing. The surgery is indicated when a risk is perceived by detecting excessive instability and early remodelling of the joint but must be performed before the structural changes become too advanced to achieve the desired results.
Follow-up studies have indicated that osteoarthritis continues to develop in surgically treated joints but that this development is not linear or time-related (DeLuke et al, 2012; Boyd et al, 2007; Hurley et al, 2007). Additional slowing of degenerative disease may be gained by instituting a good rehab programme post-surgery. Clinical results post-surgery are often reported to be good.
2. Juvenile Pubic Symphysiodesis (JPS) in hip dysplasia
This is a novel idea which involves surgically fusing the pubis using cautery in young puppies. This has the effect of altering the shape of the pelvis as the bone develops and results in a slightly different shaped pelvis which has increased acetabular coverage of the femoral heads.
One of the challenges of the surgery is that it depends on very early detection of instability and a decision about whether the instability is likely to produce clinical problems later in life.
For best results surgery must be performed early, before the puppies are 22 weeks old. Puppies are most successfully identified as candidates for this intervention by using the Penn Hip assessment technique.
Puppies treated with JPS were demonstrated to have a much-reduced incidence of OA compared to nontreated animals when followed through to two years of age (Dueland et al, 2010).
3. TPLO and TTA in cruciate disease
Both of these techniques are commonly used to treat cruciate deficient joints. They act to alter the forces passing through the joint when the animal is weight-bearing. The joint is stabilised by reducing or eliminating disruptive cranial tibial thrust.
Dynamically stabilising the joint during weight-bearing in this way restores clinical function; however, there is evidence that it does not entirely preclude osteoarthritis, which develops and progresses in postsurgical joints (Dembour and Chancrin, 2006; DeLuke et al, 2012; Molsa et al, 2014).
Following the principles of multimodal OA management and instituting rigorous post-operative rehabilitation has been demonstrated to improve both outcome and function post-surgery (Marsolais et al, 2002); as has instituting a weight reduction or management programme to control body weight and avoid obesity (Wuchererer et al, 2013).
Osteoarthritis progresses rapidly in the non-treated cruciate deficient joint (Figure 2) and surgery plays a large role in limiting this. Once again it is an error to think that OA will not develop post cruciate stabilisation and this fact should be communicated to owners of animals having this surgery. Instituting early OA management strategies with the pet owner will maximise long-term success.
4. Osteotomy techniques in elbow dysplasia
Dysplasia of the elbow is usually the cause of a rapidly progressive and debilitating osteoarthritis of the elbow joint. This joint tolerates any damage very poorly and pain and lameness are present in very young dogs with the disease.
The main site of pathology is in the medial compartment of the joint with coronoid damage and focal loss of cartilage on both the ulna and adjacent humeral articular surface (Figure 3).
There are a number of surgical strategies aimed at either or both eliminating any incongruity existing in the joint and reducing the focal load on the medial joint surfaces. Techniques include:
- Osteotomy of the ulna – Proximal Ulna Osteotomy (PUO) – Proximal Abducting Ulna Osteotomy (PAUL) – (Pfiel, 2012)
- Osteotomy of the humerus – Closing Wedge Osteotomy (Fujita et al, 2003) – Sliding Humeral Osteotomy (SHO) (Mason et al, 2008)
SHO has been demonstrated to reduce the load on the medial compartment by 25-28% depending on the amount of translation (Mason, 2008). Cartilage “healing” by fibrocartilage covering the full thickness defects in the medial compartment 12 months post SHO has been described (Fitzpatrick et al, 2009) in addition to good clinical recovery in most cases at 26 weeks post-surgery.
5. Canine Unicompartmental Elbow Prosthesis (CUE)
An alternative approach to medial compartment disease is afforded by the use of a uni-compartmental joint prosthesis.
Clinical recovery is slow after this procedure, taking six months. Final outcomes have been published by Cook (2015) with 49% of treated dogs achieving full function and a further 49% described as having only acceptable function.
Surgery in late stage osteoarthritis
Surgery has been used to salvage joints with end stage disease which are no longer functional. Salvage can be accomplished using a variety of surgical techniques, but most fall into one of three general groups:
1. Excision Arthroplasty
2. Arthrodesis
3. Total Joint Replacement
The procedure selected is largely dictated by the joint involved.
1. Excision Arthroplasty
Mainly performed in cases with hip arthritis but can be used in the TM joint, the shoulder and the elbow with varying results. In the hip a good outcome can be obtained due to the formation of a functional pseudoarthrosis. This is largely dependent on surgical technique with the most common fault being incomplete removal of the femoral head, resulting in pain and failure to form a false joint.
Early mobilisation of the joint post-surgery (from week two) is also essential in establishing a mobile pseudoarthrosis. The chance of a good outcome is less likely in large or giant breeds.
2. Arthrodesis
Fusion of a joint achieves success by eliminating joint movement which is the source of pain and lack of function. The success of the procedure is totally dependent on the joint selected.
Joints like the carpus and hock can be fused in a functional position and produce good results as immobility of these joints carries little consequence mechanically for good ambulation. In contrast, the elbow and stifle pose challenges as movement of both of these joints during ambulation is key to normal gait. Therefore, other solutions are often looked for rather than arthrodesis.
Arthrodesis of the stifle can yield good functional results, particularly in smaller dogs and cats. The angle of fusion is critical to this success, the main problem being in setting the joint in too high a degree of extension. The elbow joint can also be arthrodesed, but it is more challenging to get a good functional result.
The shoulder joint, interestingly, is a very good prospect for arthrodesis in all breeds. Immobility of the shoulder joint is compensated for by movement of the scapula against the body wall and increased dependence on elbow flexion and extension.
3. Total Joint Replacement
Total joint replacement is the common solution to end stage arthritis in humans and is becoming increasingly popular as different prostheses are developed in animals. Prostheses are now available for hips, elbows, stifles, hocks and shoulders.
Limitations are introduced by the skill and hardware required and the resultant costs. At best, single or pairs of joints are treated. Results vary depending on the joint involved and the prosthesis.
- Hip – expect excellent functional outcome with few complications (Figure 4).
- Stifle – good results.
- Elbow – variable results with all prostheses/salvage option rather than expect full function.
- Shoulder/hock – too early to say how functional the results from these are.
Summary
There are many ways where the correct and timely use of surgery can make a big impact on immediate function and the prognosis of an animal destined to develop OA or suffering from advanced disease. Surgery, however, should not be regarded as the main option in the management of OA joints, rather as one of the key tools available among many others to produce a good outcome in the population of patients with osteoarthritis.
We can modify, help and improve but until we can prevent OA or have a joint replacement option which is as good as the original, OA should not be regarded as a surgical disease.
References and further reading
DeLuke, A. M. et al (2012) Comparison of radiographic osteoarthritis scores in dogs less than 24 months or greater than 24 months following tibial plateau levelling osteotomy. Can Vet J 53: 1,095.
Boyd, D. J. et al (2007) Radiographic and functional evaluation of dogs at least a year after tibial plateau levelling osteotomy. Can Vet J 48: 392.
Hurley, C. R. et al (2007) Progression of radiographic evidence of osteoarthritis following tibial plateau levelling osteotomy in dogs with CCL rupture; 295 cases. JAVMA 230: 1,674.
Dueland, R. T. et al (2010) Canine Hip Dysplasia treated by juvenile symphysiodesis. VCOT 5.
Dembour, Th. and Chancrin, J.-L. (2006) Long term analysis of the progression of hip arthrosis after triple pelvic osteotomy. EJCAP 16: 161.
Molsa, S. H., Hyytiainen, H. K., HielmBjorkman, A. K., Laitinen-Vapaavuori, O. M. (2014) Long term functional outcomes after surgical repair of cranial cruciate disease in dogs. BMC Vet Res 10: 266.
Marsolais, G. S., Dvorak, G. and Conzemius, M. G. (2002) Effects of postoperative rehabilitation on limb function after CCL repair in dogs. JAVMA 220: 1,325-1,330.
Wucherer, K. L., Conzemius, M. G., Evans, R. et al (2013) Short and long term outcomes for overweight dogs with cranial cruciate ligament rupture treated surgically or non-surgically. JAVMA 242: 1,364-1,372.
Pfeil, I., Böttcher, P. and Starke, A. (2012) Proximal abduction ulna osteotomy (PAUL) for medial compartment diseases in dogs with ED. Proceedings of the 16th European Society of Veterinary Orthopaedics and Traumatology Congress. Bologna, Italy: pp314-318.
Fujita, Y., Schulz, K. S., Mason, D. R. et al (2003) Effect of humeral osteotomy on joint surface contact in canine elbow joints. AJVR 64: 506-511.
Mason, D. R., Schulz, K. S., Fujita, Y. et al (2008) Measurement of humeroradial and humeroulnar transarticular joint forces in the canine elbow joint after humeral wedge and humeral slide osteotomies. Vet Surg 37 (1): 63-70.
Fitzpatrick, N., Yeadon, R., Smith, T. et al (2009) Techniques of application and initial clinical experience with sliding humeral osteotomy for treatment of medial compartment disease of the canine elbow. Vet Surg 38: 261-278.
Cook, J. et al (2015) Clinical outcomes associated with the initial use of the Canine Uni-compartmental Elbow(CUE) Arthroplasty System. Can Vet J 56: 971.
