Cranial cruciate ligament (CrCL) disease is a leading cause of hindlimb lameness in dogs. Stifle radiographs are often taken as part of the routine workup of CrCL cases, but most general practitioners do not measure the tibial plateau angle.<\/p>\n
This article describes how to perform this measurement and its usefulness in determining suitability of certain CrCL treatments.<\/p>\n
Take-Home Points<\/strong><\/p>\n <\/p>\n Cranial cruciate ligament (CrCL) disease continues to be a leading cause of hindlimb lameness in dogs. Multiple biomechanical and biological factors are thought to contribute to CrCL injury.1-4<\/sup> <\/span><\/p>\n Stifle radiographs are often taken as part of the routine workup of CrCL cases, but most general practitioners do not measure the tibial plateau angle (TPA). This additional step can be performed with only slight modification of the radiographic procedure. Many conservative and surgical treatment options exist for CrCL disease, and knowledge of a patient\u2019s TPA can help determine the most suitable treatment and aid clients in making the best decision for their pet.<\/span><\/p>\n While a direct association between the TPA as an isolated risk factor in CrCL injury is not established,5,6<\/sup> studies have shown higher mean TPAs in dogs with CrCL disease compared with healthy dogs7,8<\/sup> and an increased risk of contralateral CrCL injury.9<\/sup> Mechanically, cranial tibial thrust during loading of the stifle joint increases in magnitude with increasing TPA and can result in repetitive CrCL microtrauma.10-15<\/sup> Associated inflammatory changes lead to progressive CrCL injury, pain, and osteoarthritis in affected joints.1,2<\/sup> Overall, an increased TPA is considered a contributing predisposing factor in CrCL disease, along with other conformational abnormalities such as straight stifle angle and narrowed intercondylar notch.1,2<\/sup><\/span><\/p>\n The lateral stifle projection is most useful in diagnosing CrCL injury, although caudocranial radiographs should also be performed for assessment of osteoarthritis and other abnormalities. For the lateral projection, the patient is positioned in lateral recumbency with the contralateral limb pulled forward (<\/span>BOX 1<\/b><\/span>). <\/span><\/p>\n Figure 1. Lateral stifle patient positioning. Limb positioners or tape and sandbags can be used to stabilize the limbs. The opposite limb should be pulled cranially rather than caudally to avoid rotation of the limb of interest.<\/p><\/div><\/li>\n Conventionally, the stifle and tarsus are positioned at 90\u00b0 of flexion, although this angle has been found to be less important than achieving a straight, well-centered view.16<\/sup> A true lateral position is achieved when the femoral and tibial condyles are superimposed (<\/span>FIGURES 2 AND 3<\/b><\/span>).17<\/sup> <\/span><\/p>\n\n
Role of the TPA in the Pathogenesis of CrCL Disease<\/h2>\n
Stifle Radiographs<\/h2>\n
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