J Vet Sci.  2020 Sep;21(5):e69. 10.4142/jvs.2020.21.e69.

Effects of quadriceps angle on patellofemoral contact pressure

• Yoo YH
• Lee SJ
• Jeong Sw

• KMID: 2507285
• DOI: http://doi.org/10.4142/jvs.2020.21.e69

Abstract

Background
An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint.
Objectives
The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs.
Methods
Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared.
Results
Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001).
Conclusions
Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided

Keyword

Patellofemoral pressure; patellar luxation; quadriceps angle; dogs