J Vet Sci.  2014 Dec;15(4):563-568. 10.4142/jvs.2014.15.4.563.

Feasibility of utilizing the patellar ligament angle for assessing cranial cruciate ligament rupture in dogs

• Lee JH
• Jeong SW

• KMID: 2070244
• DOI: http://doi.org/10.4142/jvs.2014.15.4.563

Abstract

The patellar ligament angle (PLA) was assessed in 105 normal stifle joints of 79 dogs and 33 stifle joints of 26 dogs with a ruptured cranial cruciate ligament (CrCL). The PLA of stifles with complete CrCL rupture was significantly lower than that of normal stifles, particularly at a flexion angle of 60~80degrees in both plain and stress views. If the PLA was <90.55degrees on the stress view with a 60~80degrees flexion angle, the dog was diagnosed with a complete rupture of the CrCL with a sensitivity of 83.9% and specificity of 100%. In conclusion, measuring the PLA is a quantitative method for diagnosing complete CrCL rupture in canines.

Keyword

cranial cruciate ligament rupture; dog; patellar ligament angle

MeSH Terms

Animals
Anterior Cruciate Ligament/*injuries/radiography
Dogs/*injuries
Patellar Ligament/physiology/*radiography
Radiography/*veterinary
Retrospective Studies
Rupture/veterinary

Figure

• 

  Fig. 1 Mediolateral radiographic view of a dog with a normal stifle joint to illustrate measuring the angles α and β. Angle α was defined as the angle between the patellar ligament (pl) and tibial plateau (p). The flexion angle (β) of the stifle joint was measured between the long axis of the femur (af) and long axis of the tibia (at).

• 

  Fig. 2 Inclination of angle α at the incident stifle flexion along with angle β in dogs with complete rupture of the CrCL (triangles), after surgery (squares), and normal stifles (circles). The equation of the linear regression analysis for α vs. β before surgery was as follows: α = -0.78β + 118 (r2 = 0.602; p < 0.001; continuous line). The equation of the linear regression analysis for α vs. β after surgery was as follows: α = -0.56β + 113 (r2 = 0.314; p < 0.001; wide dashed line). The small dashed line is the regression line for normal dogs: α = -0.32β + 116 (r2 = 0.416; p < 0.001).

• 

  Fig. 3 Comparison of the patellar ligament angle (PLA) at a 40~60° (A) or 60~80° (B) flexion angle. Differences were considered to be significant at *p < 0.05, **p < 0.01, and ***p < 0.001.

• 

  Fig. 4 Receiver operating characteristic (ROC) curves for the PLA with a 40~60° flexion angle on the stress (A) and plain views (B), and with a 60~80° flexion angle on the stress (C) and plain views (D). (A) The area under the curve (AUC) was 0.949. With a 92.40° cutoff value, the PLA measurement had a sensitivity of 90.0% and specificity of 100%. (B) The AUC was 0.686. With a 94.51° cutoff value, the PLA measurement had a sensitivity of 86.0% and specificity of 61.5%. (C) The AUC was 0.945. With a 90.55° cutoff value, the PLA measurement had a sensitivity of 83.9% and specificity of 100%. (D) The AUC was 0.785. With a 90.76° cutoff value, the PLA measurement had a sensitivity of 83.9% and specificity of 75.0%.

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