34th Annual Scientific Meeting proceedings

When dealing with cartilage defects, one must distinguish between two types of defects: (1) those resulting from osteochondritis dissecans (OCD) in juvenile dogs and (2) degenerative defects, which arise from some form of mechanical disease, inducing accelerated wear of hyaline joint cartilage over time. The latter mostly occurs in older dogs; however, excessive forms of hip or elbow dysplasia, for example, can cause wear of a joint even before the patient reaches maturity. A partial or total joint prosthesis is typically employed as a synthetic resurfacing technique for such lesions because the lesions are bipolar, necessitating bipolar resurfacing, with metal (e.g., CoCr) on one side and polyethylene as a liner on the opposing joint surface.

When addressing large OCD (osteochondritis dissecans) lesions, the typical case involves a young dog, usually between 5 and 10 months old, with OCD present in the shoulder, elbow, stifle, or tarsal joint. The standard surgical approach focuses on encouraging fibrocartilage growth at the cleaned lesion site, typically through minimally invasive arthroscopy. However, the success of these procedures can be limited, particularly for lesions in high-pressure areas of the joints, potentially leading to less than optimal functional results. The use of biological resurfacing techniques, such as transplanting autologous osteochondral plugs from the same stifle, has demonstrated effective clinical performance with minimal complications.[1-4] Particularly large, round lesions are well-suited for osteochondral resurfacing. The primary challenge in this procedure stems from the freehand technique used both in preparing the lesion bed and in harvesting the osteochondral transplant. This method can lead to inaccuracies, with an average deviation from perpendicular alignment around 7 degrees. It is well established that the long-term success of the resurfacing relies heavily on the quality of the reconstruction, which should aim to replicate the natural shape of the articular surface.[5] Therefore, surgeons should critically assess the shape of their reconstruction. Often, the curvature of the joint surface is restored in a suboptimal way. Since achieving “perfect” orientation and positioning is crucial, the use of surgical templates is recommended to significantly enhance accuracy..[6]

Unfortunately, since the initial clinical implementation of osteochondral resurfacing in dogs in the early 2000s, [4] no comprehensive long-term evaluations have been conducted. The most recent studies only follow patients up to six months post-surgery, [1] which is insufficient to assess the long-term effectiveness of the procedure. In comparison, when considering human patients with focal cartilage lesions within the knee joint, approximately 10% eventually require conversion to total knee arthroplasty (TKA) after osteochondral resurfacing. [7] However, over 90% of these patients exhibit excellent joint survival rates and report satisfactory outcomes.

An alternative to autologous resurfacing is allografting, a technique that is widely used in humans, especially in North America. In dogs, allograft resurfacing has been employed for various conditions and has shown promising clinical results. However, it is currently unknown whether allografts will perform as well as autografts in the long term.

Despite the extensive clinical history of using OATS for OCD resurfacing in dogs, there is still limited knowledge regarding its long-term effectiveness in dogs with naturally occurring OCD lesions.

References

1. Cinti, F., L. Vezzoni, and A. Vezzoni, A New Generation of Osteochondral Autograft Transfer System for the Treatment of Osteochondritis Dissecans of the Femoral Condyle: Clinical Experience in 18 Dogs. Vet Comp Orthop Traumatol, 2022.
2. Cook, J.L. and D.B. Fox, Development and implementation of osteochondral autografting in dogs. Vet Comp Orthop Traumatol, 2005. 18(3): p. A43.
3. Cook, J.L., C.C. Hudson, and K. Kuroki, Autogenous osteochondral grafting for treatment of stifle osteochondrosis in dogs. Vet Surg, 2008. 37(4): p. 311-321.
4. Frank, M., Einsatz der osteochondralen Transplantation (Mosaicplasty) in der Therapie der Osteochondrosis dissecans (OCD) des Kniegelenkes beim Hund. Beschreibung der Technik und erste Erfahrungen anhand von fünf Fällen. [Use of osteochondral grafting for therapy of osteochondrosis dissecans (OCD) in the canine knee joint. Description of the technique and preliminary results following the treatment of five cases]. Tierärztl Prax, 2003. 31 (K): p. 346-355.
5. Kunz, M., et al., Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries: An Animal Trial. Cartilage, 2013. 4(2): p. 153-64.
6. Sebastyan, S., et al., Image-guided techniques improve accuracy of mosaic arthroplasty. Int J Comput Assist Radiol Surg, 2016. 11(2): p. 261-9.
7. Rollmann, M.F., et al., Long-term results of reconstructing the joints' articular surface in the knee and ankle with the surgical diamond instrumentation (SDI). Eur J Trauma Emerg Surg, 2021. 47(5): p. 1627-1634.