Patellofemoral Update focuses on the causes, prevention and treatment of patellofemoral disorders. The blog is sponsored by The Patellofemoral Foundation whose mission is to improve the care of individuals with anterior knee pain through targeted education and research. The Patellofemoral Foundation offers additional online education resources on its website.

BLOG: TT-TG distance and our criteria for a tibial tubercle transfer

John P. Fulkerson
John P. Fulkerson

Carlson and colleagues recently wrote: “The static [tibial tubercle to trochlear groove] TT-TG distance cannot accurately predict dynamic lateral displacement of the patella. A large percentage of patients with patellofemoral pain and pathologically large TT-TG distances may have neutral to medial maltracking patterns.”

Those doing patellofemoral surgery should review and discuss this. Of course, this raises questions about our criteria for doing tibial tubercle transfer. Don’t we want to do a tibial tubercle transfer to correct lateral tracking? Not too sure the TT-TG in isolation is reliable enough for surgical decision-making.


Carlson VR, et al. Am J Sports Med. 2017;doi:10.1177/0363546517700119.

John P. Fulkerson, MD, is a clinical professor of orthopedic surgery at the University of Connecticut School of Medicine and practices at Orthopedic Associates of Hartford in Farmington, Connecticut. He is also president of The Patellofemoral Foundation.

Disclosure: Fulkerson reports he receives royalties from DJO Global and is a patent holder for DJO Global.

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