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Review
. 2018 Jun;11(2):261-265.
doi: 10.1007/s12178-018-9481-4.

Use of TT-PCL versus TT-TG

Jacqueline M Brady  1 , Adam S Rosencrans  2 , Beth E Shubin Stein  3
Affiliations
Review

Use of TT-PCL versus TT-TG

Jacqueline M Brady et al. Curr Rev Musculoskelet Med. 2018 Jun.

Abstract

Purpose of review: The tibial tubercle-to-trochlear groove (TT-TG) distance and tibial tubercle-to-posterior cruciate ligament (TT-PCL) distance have both been proposed for use in the evaluation of patients with patellofemoral instability.

Recent findings: While the TT-TG value may be confounded by several factors, including age, gender, body mass index, and varying degrees of knee flexion on cross-sectional imaging, recent literature supports its utility for differentiation of patients with and without patellofemoral instability, and stratification of patients with and without coronal malalignment. The TT-PCL describes pure lateralization of the tibial tubercle, and may be used in conjunction with the TT-TG to better understand the path taken by the extensor mechanism of the knee joint. The TT-TG measurement is superior to the TT-PCL measurement for differentiating patients with patellofemoral instability from their stable counterparts, though TT-PCL may be useful in conjunction with TT-TG for better understanding the path of the extensor mechanism across the knee joint.

Keywords: Instability; Patellofemoral; TT-PCL; TT-TG; Tibial tubercle osteotomy.

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Conflict of interest statement

Conflict of Interest

Beth E. Shubin Stein is a consultant for Arthrex. Other authors have no conflicts of interest.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.

Figures

Fig. 1
Fig. 1
Tibial tubercle-to-trochlear groove distance, as measured on MRI. In this case, the tibial tubercle (TT) is measured at the most distal aspect of the patellar tendon insertion, and the trochlear groove (TG) is measured at the most proximal axial image with a complete cartilaginous trochlea. The value is measured in parallel fashion to the posterior condylar line of the femur
Fig. 2
Fig. 2
Tibial tubercle-to-PCL distance, as measured on MRI. a The medial border of the PCL is noted on the most distal axial image in which the ligament can be clearly identified. b The posterior condylar line of the tibia is defined more distally on the tibia, just below the articular surface but proximal to the fibular head. c The posterior tibial condylar line is transposed to the axial image with the clearest depiction of the knee joint, and a perpendicular line is drawn through the PCL point from the intercondylar line. d The TT-PCL is measured from the center of the tibial tubercle to the perpendicular line shown in c
See this image and copyright information in PMC

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