Dealing with Canine Cruciate Ligament Disease (incl. TPLO)

Although cranial cruciate ligament deficiency (CCLD) is, as is often stated, the commonest cause of pelvic limb lameness in the dog, relatively little progress has been made in understanding the aetiopathogenesis of the condition and its management. A plethora of surgical procedures has been designed to prevent cranial translation of the tibia relative to the femur and these surgical procedures yield a wide range of outcomes. It is inappropriate to extrapolate meaningful data from the human condition as it is almost always traumatic in origin. Therefore it is not surprising that surgical techniques that are successfully employed in the human field are not nearly as effective in the canine patient. 

A number of hypotheses have been suggested as potential underlying cause: chronic overstrain, immunemediated arthritis, conformational deformities, anticollagen antibodies, narrow intercondylar notch width, inactivity in puppyhood and repetitive chronic trauma.

Diagnostically CCLD joints are palpably unstable (cranial draw and/or cranial tibial thrust). However, joints where only a partial CCL rupture is present may have no or only a mild instability. Other palpable abnormalities such as a firm thickening on the medial side of the joint and synovial effusion may suggest that a partial cruciate injury is present. Further investigations that have been employed include arthroscopy, magnetic resonance imaging, “dynamic” radiography (radiography while performing a tibial compression test) and ultrasonography.

The most commonly performed procedures in the UK have been for many years the lateral retinacular suture (LRS) and the “over the top” (OTT). Published studies suggest that the OTT procedure may not yield as good functional results as the LRS. Both procedures have well recognised deficiencies. These stabilisation procedures often result in stretching and/or failure of the graft (synthetic or autogenous) and a return of tibial translation. The long term benefits of these surgeries are thought to be due to the postoperative development of periarticular fibrosis. Arguably the most important aspect of both surgeries is joint inspection with particular regard to meniscal injuries.

There has been little modification of the original overthe-top procedure described by Paatsama. The decision to use fascia lata plus or minus a portion of the patellar ligament is surgeon preference and has no effect on outcome. Also the graft may be fashioned into a tube, doubled, twisted or passed as a straight strip. Similarly, none of these options have demonstrated a significant effect on outcome. The graft can be drawn under the cranial inter-meniscal ligament and this may more accurately mimic the normal position of the cranial cruciate ligament (CCL). Arthroscopic positioning of the under and over graft has been described in the dog. [...]