Patellar instability

Case contributed by Bahman Rasuli
Diagnosis certain

Presentation

Recurrent patellar dislocation on the right side.

Patient Data

Age: 20 years
Gender: Female
ct

The tibial tuberosity (TT) to trochlear groove (TG)  distance of the right knee is measuring about 21.1 mm.

Case Discussion

Distance from tibial tuberosity to trochlear groove (TT-TG) is one of the best measures for patellar instability.

Range:

  • normal : <15 mm
  • borderline : 15-20 mm
  • abnormal : >20 mm

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