Skip to main content
Log in

The contribution of the tibial tubercle to patellar instability: analysis of tibial tubercle–trochlear groove (TT-TG) and tibial tubercle–posterior cruciate ligament (TT-PCL) distances

Knee Surgery, Sports Traumatology, Arthroscopy Aims and scope

Abstract

Purpose

The purpose of this study is to assess the reliability of measuring the tibial tubercle to posterior cruciate (TT-PCL) distance compared to the tibial tubercle to trochlear groove (TT-TG) distance on magnetic resonance imaging (MRI), establish baseline TT-PCL values in patellar instability patients, and determine the predictive value of an excessive TT-PCL distance (≥24 mm) for recurrent patellar instability compared to a TT-TG distance ≥20 mm.

Methods

TT-TG and TT-PCL distances were calculated on MRI in a randomized and blinded fashion by two reviewers on 54 patients (59 knees) with patellar instability. Interobserver reliability was assessed using interclass correlation coefficients (ICC). TT-PCL distances were also assessed to establish mean values in patellar instability patients. The ability of excessive TT-PCL and TT-TG distances to predict recurrent instability was assessed by comparing odds ratios, sensitivities, and specificities.

Results

Interobserver reliability was excellent for both TT-TG (ICC = 0.978) and TT-PCL (ICC = 0.932). The mean TT-PCL in these 59 knees was 21.7 mm (standard deviation 4.1 mm). Twelve (20 %) of 59 knees had a single dislocation, and 47 (80 %) exhibited 2 or more dislocations. The odds ratios, sensitivities, and specificities of a TT-TG distance ≥20 mm for identifying patients with recurrent dislocation were 5.38, 0.213, and 1.0, respectively, while those of a TT-PCL distance ≥24 mm were 1.46, 0.298, and 0.583, respectively. Of the 10 knees with a TT-TG distance ≥20 mm, all 10 (100 %) had recurrent instability, while 14 (73.7 %) of the 19 knees with a TT-PCL ≥24 mm experienced multiple dislocations (n.s.).

Conclusion

Both TT-PCL and TT-TG can be measured on MRI with excellent interobserver reliability. In this series, the mean TT-PCL value in patients with patellar instability was 21.8 mm, but the range was broad. A TT-PCL distance ≥24 mm was found to be less predictive of recurrent instability in this series. For patients experiencing multiple episodes of patellar instability in the setting of a normal TT-TG distance, obtaining the TT-PCL measurement may provide a more focused assessment of the tibial contribution to tubercle lateralization.

Level of evidence

III.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2

References

  1. Arendt EA, Fithian DC, Cohen E (2002) Current concepts of lateral patella dislocation. Clin Sports Med 21(3):499–519

    Article  PubMed  Google Scholar 

  2. Balcarek P, Jung K, Ammon J, Walde TA, Frosch S, Schuttrumpf JP, Sturmer KM, Frosch KH (2010) Anatomy of lateral patellar instability: trochlear dysplasia and tibial tubercle-trochlear groove distance is more pronounced in women who dislocate the patella. Am J Sports Med 38(11):2320–2327

    Article  PubMed  Google Scholar 

  3. Balcarek P, Jung K, Frosch KH, Sturmer KM (2011) Value of the tibial tuberosity-trochlear groove distance in patellar instability in the young athlete. Am J Sports Med 39(8):1756–1761

    Article  PubMed  Google Scholar 

  4. Beaconsfield T, Pintore E, Maffulli N, Petri GJ (1994) Radiological measurements in patellofemoral disorders. A review. Clin Orthop Relat Res 308:18–28

    Google Scholar 

  5. Camp CL, Heidenreich MJ, Dahm DL, Bond JR, Collins MS, Krych AJ (2014) A simple method of measuring tibial tubercle to trochlear groove distance on MRI: description of a novel and reliable technique. Knee Surg Sports Traumatol Arthrosc. doi:10.1007/s00167-014-3405-7

    PubMed  Google Scholar 

  6. Camp CL, Stuart MJ, Krych AJ, Levy BA, Bond JR, Collins MS, Dahm DL (2013) CT and MRI measurements of tibial tubercle-trochlear groove distances are not equivalent in patients with patellar instability. Am J Sports Med 41(8):1835–1840

    Article  PubMed  Google Scholar 

  7. Caplan N, Lees D, Newby M, Ewen A, Jackson R, St Clair Gibson A, Kader D (2014) Is tibial tuberosity-trochlear groove distance an appropriate measure for the identification of knees with patellar instability? Knee Surg Sports Traumatol Arthrosc 22(10):2377–2381

    Article  CAS  PubMed  Google Scholar 

  8. Caton JH, Dejour D (2010) Tibial tubercle osteotomy in patello-femoral instability and in patellar height abnormality. Int Orthop 34(2):305–309

    Article  PubMed  PubMed Central  Google Scholar 

  9. Colvin AC, West RV (2008) Patellar instability. J Bone Joint Surg Am 90(12):2751–2762

    Article  PubMed  Google Scholar 

  10. Dejour D, Le Coultre B (2007) Osteotomies in patello-femoral instabilities. Sports Med Arthrosc 15(1):39–46

    Article  PubMed  Google Scholar 

  11. Dejour H, Walch G, Nove-Josserand L, Guier C (1994) Factors of patellar instability: an anatomic radiographic study. Knee Surg Traumatol Arthrosc 2(1):19–26

    Article  CAS  Google Scholar 

  12. Fithian DC, Paxton EW, Stone ML, Silva P, Davis DK, Elias DA, White LM (2004) Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 32(5):1114–1121

    Article  PubMed  Google Scholar 

  13. Hingelbaum S, Best R, Huth J, Wagner D, Bauer G, Mauch F (2014) The TT-TG Index: a new knee size adjusted measure method to determine the TT-TG distance. Knee Surg Sports Traumatol Arthrosc 22(10):2388–2395

    Article  PubMed  Google Scholar 

  14. Matsushita T, Kuroda R, Oka S, Matsumoto T, Takayama K, Kurosaka M (2014) Clinical outcomes of medial patellofemoral ligament reconstruction in patients with an increased tibial tuberosity-trochlear groove distance. Knee Surg Sports Traumatol Arthrosc 22(10):2438–2444

    Article  PubMed  Google Scholar 

  15. Nietosvaara Y, Aalto K, Kallio PE (1994) Acute patellar dislocation in children: incidence and associated osteochondral fractures. J Pediatr Orthop 14(4):513–515

    Article  CAS  PubMed  Google Scholar 

  16. Pandit S, Frampton C, Stoddart J, Lynskey T (2011) Magnetic resonance imaging assessment of tibial tuberosity-trochlear groove distance: normal values for males and females. Int Orthop 35(12):1799–1803

    Article  PubMed  PubMed Central  Google Scholar 

  17. Seitlinger G, Scheurecker G, Hogler R, Labey L, Innocenti B, Hofmann S (2012) Tibial tubercle-posterior cruciate ligament distance: a new measurement to define the position of the tibial tubercle in patients with patellar dislocation. Am J Sports Med 40(5):1119–1125

    Article  PubMed  Google Scholar 

  18. Shrout PE, Fleiss JL (1979) Intraclass correlations: uses in assessing rater reliability. Psychol Bull 86(2):420–428

    Article  CAS  PubMed  Google Scholar 

  19. Smith TO, McNamara I, Donell ST (2013) The contemporary management of anterior knee pain and patellofemoral instability. Knee 20(suppl 1):S3–S15

    Article  PubMed  Google Scholar 

  20. Wilcox JJ, Snow BJ, Aoki SK, Hung M, Burks RT (2012) Does landmark selection affect the reliability of tibial tubercle-trochlear groove measurements using MRI? Clin Orthop Relat Res 470(8):2253–2260

    Article  PubMed  PubMed Central  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Aaron J. Krych.

Ethics declarations

Conflict of interest

Each author certifies that he or she has no commercial associations (e.g. consultancies, stock ownership, equity interest, patent/licensing arrangements) that might pose a conflict of interest in connection with the submitted article.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Heidenreich, M.J., Camp, C.L., Dahm, D.L. et al. The contribution of the tibial tubercle to patellar instability: analysis of tibial tubercle–trochlear groove (TT-TG) and tibial tubercle–posterior cruciate ligament (TT-PCL) distances. Knee Surg Sports Traumatol Arthrosc 25, 2347–2351 (2017). https://doi.org/10.1007/s00167-015-3715-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00167-015-3715-4

Keywords

Navigation