Upright weight-bearing CT of the knee during flexion: changes of the patellofemoral and tibiofemoral articulations between 0° and 120°
- 413 Downloads
To prospectively compare patellofemoral and tibiofemoral articulations in the upright weight-bearing position with different degrees of flexion using CT in order to gain a more thorough understanding of the development of diseases of the knee joint in a physiological position.
Materials and methods
CT scans of the knee in 0°, 30°, 60° flexion in the upright weight-bearing position and in 120° flexion upright without weight-bearing were obtained of 10 volunteers (mean age 33.7 ± 6.1 years; range 24–41) using a cone-beam extremity-CT. Two independent readers quantified tibiofemoral and patellofemoral rotation, tibial tuberosity–trochlear groove distance (TTTG) and patellofemoral distance. Tibiofemoral contact points were assessed in relation to the anteroposterior distance of the tibial plateau. Significant differences between degrees of flexion were sought using Wilcoxon signed-rank test (P < 0.05).
With higher degrees of flexion, internal tibiofemoral rotation increased (0°/120° flexion; mean, 0.5° ± 4.5/22.4° ± 7.6); external patellofemoral rotation decreased (10.6° ± 7.6/1.6° ± 4.2); TTTG decreased (11.1 mm ±3.7/−2.4 mm ±6.4) and patellofemoral distance decreased (38.7 mm ±3.0/21.0 mm ±7.0). The CP shifted posterior, more pronounced laterally. Significant differences were found for all measurements at all degrees of flexion (P = 0.005–0.037), except between 30° and 60°. ICC was almost perfect (0.80–0.99), except for the assessment of the CP (0.20–0.96).
Knee joint articulations change significantly during flexion using upright weight-bearing CT. Progressive internal tibiofemoral rotation leads to a decrease in the TTTG and a posterior shift of the contact points in higher degrees of flexion. This elucidates patellar malalignment predominantly close to extension and meniscal tears commonly affecting the posterior horns.
KeywordsUpright weight-bearing CT Weight-bearing knee joint alignment Patellofemoral Tibiofemoral Contact point
Compliance with ethical standards
Conflict of interest
No potential conflicts of interest to disclose.
- 3.Dejour H (1972) Posttraumatic laxity of the knee. Long-standing laxity. Physiopathology of chronic laxity of the knee. Rev Chir Orthop Reparatrice Appar Mot 58(Suppl 1):61–70Google Scholar
- 10.Hamai S, Moro-oka TA, Dunbar NJ, Miura H, Iwamoto Y, Banks SA (2013) In vivo healthy knee kinematics during dynamic full flexion. Biomed Res Int 2013:717546Google Scholar
- 15.Izadpanah K, Weitzel E, Vicari M, Hennig J, Weigel M, Sudkamp NP, Niemeyer P (2014) 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 22(11):2655–2661CrossRefPubMedGoogle Scholar
- 27.Rosner B (2011) The intraclass correlation coefficient. In: Rosner B (ed) Fundamentals of biostatistics, 7th edn. Brooks/Cole, Cengage Learning, Boston, pp 568–571Google Scholar
- 31.Tanaka MJ, Elias JJ, Williams AA, Carrino JA, Cosgarea AJ (2015) Correlation between changes in tibial tuberosity-trochlear groove distance and patellar position during active knee extension on dynamic kinematic computed tomographic imaging. Arthroscopy. doi: 10.1016/j.arthro.2015.03.015 Google Scholar
- 34.Tennant S, Williams A, Vedi V, Kinmont C, Gedroyc W, Hunt DM (2001) Patello-femoral tracking in the weight-bearing knee: a study of asymptomatic volunteers utilising dynamic magnetic resonance imaging: a preliminary report. Knee Surg Sports Traumatol Arthrosc 9(3):155–162CrossRefPubMedGoogle Scholar
- 38.Wunschel M, Leichtle U, Obloh C, Wulker N, Muller O (2011) The effect of different quadriceps loading patterns on tibiofemoral joint kinematics and patellofemoral contact pressure during simulated partial weight-bearing knee flexion. Knee Surg Sports Traumatol Arthrosc 19(7):1099–1106CrossRefPubMedGoogle Scholar