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. 2023 Jun 1;43(6):e220177. doi: 10.1148/rg.220177

Figure 21.

Sonographic assessment of patellar instability. Transverse US images of the patellar tendon can be used to quantify lateral translation at various degrees of flexion without (A) and with (B) quadriceps contraction. The distance from the lateral edge of the patellar tendon (arrow) in relation to the lateral margin of the trochlea (arrowhead) can be readily measured and indicates an increase in patellar tendon overriding with quadriceps contraction that is characteristic of maltracking.

Sonographic assessment of patellar instability. Transverse US images of the patellar tendon can be used to quantify lateral translation at various degrees of flexion without (A) and with (B) quadriceps contraction. The distance from the lateral edge of the patellar tendon (arrow) in relation to the lateral margin of the trochlea (arrowhead) can be readily measured and indicates an increase in patellar tendon overriding with quadriceps contraction that is characteristic of maltracking.