New concepts and treatment of elbow pathology in dogs (Proceedings)

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New concepts and treatment of elbow pathology in dogs (Proceedings)

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Aug 01, 2011



Management of articular cartilage lesions is based on the concept that providing blood with mesenchymal stem cell precursors access to the lesion encourages healing by formation of fibrocartilage. Several marrow stimulating techniques have been described to achieve this. Abrasion arthroplasty involves uniform removal of subchondral bone until bleeding is achieved. This can be accomplished in the canine elbow by use of either a curette or burr attachment on a small joint shaver. The shaver is usually more rapid and efficient and generally just as accurate. Another marrow stimulating technique is microfracture. In this technique numerous microcracks are created in the subchondral bone plate with a specialized micropick to allow bleeding at the lesion surface.

Indications for abrasion arthroplasty or microfracture vary with the size and degree of cartilage loss. In general, lesions small to moderate size (1-2cm in man) can be treated with resurfacing techniques. Debridement of Grade I lesions with chondromalacia is up to the discretion of the surgeon. Small areas of grade II fibrillation in the absence of other lesions also may be left undisturbed. Larger areas of Grade II cartilage disease can be treated with abrasion arthroplasty or microfracture. Grade III lesions are areas of full thickness fibrillation. Use a curette or burr to remove the diseased cartilage while being careful not to damage any of the surrounding more normal cartilage. Grade IV cartilage damage is full thickness loss of cartilage and exposure and, in some cases, eburnation of the subchondral bone. They are treated with abrasion or microfracture until adequate bleeding occurs. Producing diffuse effective bleeding varies in difficulty between joints. Combining abrasion and microfracture may help increase subchondral bleeding. In cases of eburnation it may be difficult or impossible to get significant bleeding with these techniques.

To perform abrasion arthroplasty, insert a hand burr or preferentially a power shaver burr through the instrument portal. Either method will produce significant bone debris that can clog the egress portal and impede visualization, therefore it is important to monitor and maintain the flow of fluid through the joint during this procedure. Spin the burr to remove subchondral bone over the area of the lesion. Check for resulting bleeding frequently by stopping inflow of fluid and ensuring adequate outflow to decrease the pressure in the joint. When bleeding is observed diffusely from the lesion bed, lavage the joint to remove the remaining bone debris and close routinely.

To perform microfracture, insert an appropriately angled micropick into the joint and press the tip against the subchondral bone surface. Have an assistant tap the pick handle once or twice. The pick should be held securely to avoid gouging the surface and adjacent healthy cartilage. Apply the micropick diffusely across the diseased area and check for resulting bleeding frequently by stopping inflow of fluid and ensuring adequate outflow. The penetrations should be 2-3 mm apart and 1-2mm in depth. When bleeding is observed diffusely from the lesion bed, lavage the joint to remove the remaining bone debris and close routinely.