The Normal Value of Tibial Tubercle Trochlear Groove Distance in Patients With Normal Knee Examinations Using MRI


Patellar instability is a multifactorial common knee pathology that has a high recurrence rate, and the symptoms continue and ultimately predispose the patient to chondromalacia and osteoarthritis. Tibial tuberosity-trochlear groove distance (TTTG) is very important in the assessment of patellofemoral joint instability. The purpose of this study was to report the normal value of TTTG in males and females in different age groups and to assess the reliability of MRI in measuring TTTG. All patients presenting with knee pain and normal examinations of the knee joint, with a normal MRI report, referring to Shahid Sadoughi hospital of Yazd, Iran, from April 2014 to September 2014, were included in the study. MR images were studied once by two radiologists and for the second time by one radiologist. Mean value of TTTG was reported for males and females and in three age groups. Intra- and inter-observer reliability was calculated. A total of 98 patients were eligible to evaluate during 6 months (68 male and 30 female). Mean TTTG was 10.9±2.5 mm in total, which was 10.8±2.8 mm and 11.3±2.3 mm in males and females, respectively (P>0.05). Mean TTTG in males ≤30 years, 30-50 years and, ≥51-year-old were 10.8±2.6 mm, 10.8±2.7 mm, and 10.8±2.6 mm, respectively; that was 12.1±3.4 mm, 11.4±1.9 mm, and 10.5±1.7 mm in females ≤30 years, 31-50 years and, ≥51-year-old, respectively (95% CI). The coefficient of variation was <10% for both intra- and interobserver analysis. The results of the present study showed no significant difference in TTTG value between males and females in different age groups. In addition, it demonstrated that MRI is a reliable method in assessment of TTTG and identified normal value for TTTG at 10.9±2.5 mm.

Goldblatt JP, Richmond JC. Anatomy and biomechanics of the knee. Oper Tech Sports Med 2003;11:172-86.

Tecklenburg K, Dejour D, Hoser C, Fink C. Bony and cartilaginous anatomy of the patellofemoral joint. Knee Surg Sports Traumatol Arthrosc 2006;14:235-40.

Fithian DC, Paxton EW, Stone ML, Silva P, Davis DK, Elias DA, et al. Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 2004;32:1114-21.

Atkin DM, Fithian DC, Marangi KS, Stone ML, Dobson BE, Mendelsohn C. Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. Am J Sports Med 2000;28:472-9.

Sobhan MR, Mehdinejad M, Jamaladini MH, Mazaheri M, Masoud Zare-Shehneh M, Neamatzadeh H. Association between aspartic acid repeat polymorphism of the asporin gene and risk of knee osteoarthritis: A systematic review and meta-analysis, Acta Orthop Traumatol Turc 2017. pii: S1017-995X(17)30278-X.

Colvin AC, West RV. Patellar instability. J Bone Joint Surg Am 2008;90:2751-62.

Wittstein JR, O’Brien SD, Vinson EN, Garrett Jr WE. MRI evaluation of anterior knee pain: predicting response to nonoperative treatment. Skeletal Radiol 2009;38:895-901.

Spritzer C, Courneya D, Burk Jr D, Garrett W, Strong J. Medial retinacular complex injury in acute patellar dislocation: MR findings and surgical implications. AJR Am J Roentgenol 1997;168:117-22.

Nomura E, Horiuchi Y, Inoue M. Correlation of MR imaging findings and open exploration of medial patellofemoral ligament injuries in acute patellar dislocations. Knee 2002;9:139-43.

Balcarek P, Jung K, Frosch K-H, Stürmer MK. Value of the tibial tuberosity–trochlear groove distance in patellar instability in the young athlete. Am J Sports Med 2011;39:1756-61.

Smith TO, Davies L, Toms AP, Hing CB, Donell ST. The reliability and validity of radiological assessment for patellar instability. A systematic review and meta-analysis. Skeletal Radiol 2011;40:399-414.

Saudan M, Fritschy D. [AT-TG (anterior tuberosity-trochlear groove): interobserver variability in CT measurements in subjects with patellar instability]. Rev Chir Orthop Reparatrice Appar Mot 2000;86:250-5.

Lustig S, Servien E, Selmi TAS, Neyret P. Factors affecting reliability of TT-TG measurements before and after medialization: a CT scan study. Rev Chir Orthop Reparatrice Appar Mot 2006;92:429-36.

Schoettle PB, Zanetti M, Seifert B, Pfirrmann CW, Fucentese SF, Romero J. The tibial tuberosity–trochlear groove distance; a comparative study between CT and MRI scanning. Knee 2006;13:26-31.

Thakkar RS, Del Grande F, Wadhwa V, Chalian M, Andreisek G, Carrino JA, et al. Patellar instability: CT and MRI measurements and their correlation with internal derangement findings. Knee Surg Sports TraumatolArthrosc 2016;24:3021-8.

Pandit S, Frampton C, Stoddart J, Lynskey T. Magnetic resonance imaging assessment of tibial tuberosity–trochlear groove distance: normal values for males and females. Int Orthop 2011;35:1799-803.

Wilcox JJ, Snow BJ, Aoki SK, Hung M, Burks RT. Does landmark selection affect the reliability of tibial tubercle–trochlear groove measurements using MRI? Clin Orthop Relat Res 2012;470:2253-60.

Wittstein JR, Bartlett EC, Easterbrook J, Byrd JC. Magnetic resonance imaging evaluation of patellofemoral malalignment. Arthroscopy 2006;22:643-9.

Hingelbaum S, Best R, Huth J, Wagner D, Bauer G, Mauch F. The TT-TG Index: a new knee size adjusted measure method to determine the TT-TG distance. Knee Surg Sports Traumatol Arthrosc 2014;22:2388-95.

Izadpanah K, Weitzel E, Vicari M, Hennig J, Weigel M, Südkamp NP, et al. Influence of knee flexion angle and weight bearing on the Tibial Tuberosity-Trochlear Groove (TTTG) distance for evaluation of patellofemoral alignment. Knee Surg Sports Traumatol Arthrosc 2014;22:2655-61.

Shakespeare D, Fick D. Patellar instabilitycan the TTTG distance be measured clinically? Knee 2005;12;201-4.

IssueVol 55, No 9 (2017) QRcode
Knee Anatomy Magnetic resonance imaging TTTG

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Sobhanardekani M, Sobhan MR, Nafisi Moghadam R, Nabavinejad S, Razavi Ratki SK. The Normal Value of Tibial Tubercle Trochlear Groove Distance in Patients With Normal Knee Examinations Using MRI. Acta Med Iran. 55(9):573-577.