Effects of upright weight bearing and the knee flexion angle on patellofemoral indices using magnetic resonance imaging in patients with patellofemoral instability

Fleischer, Benjamin; Rase, Marten; Schumacher, Thees; Ettinger, Max; Ostermeier, Sven; Smith, Tomas

doi:10.1007/s00167-015-3829-8

Cited by 35 publications

(79 citation statements)

References 39 publications

(71 reference statements)

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“…37 For instance, TTTG values were acquired at various flexion and extension degrees of the knee; however, it was shown that the TTTG distance increases significantly in the end-stage extension of the knee. 37,40,41 The mean TTTG values on MR images were 15.1 AE 3.2 mm at full extension, 10.0 AE 3.5 mm at 15 degrees flexion, and 8.1 AE 3.4 mm at 30 degrees flexion in a well-balanced study cohort of asymptomatic volunteers. 37 Using the MR body coil with the knee fully extended caused significantly higher TTTG values compared with MR examinations with a dedicated knee coil where the knee is slightly flexed.…”

Section: Tuberosity To the Trochlear Groove Distancementioning

confidence: 86%

Imaging of Individual Anatomical Risk Factors for Patellar Instability

Dietrich

Fucentese

Pfirrmann

2016

Semin Musculoskelet Radiol

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This review article presents several pitfalls and limitations of image interpretation of anatomical risk factors for patellar instability. The most important imaging examinations for the work-up of patients with patellar instability are the true lateral radiograph and transverse computed tomography (CT) or MR images of the knee. Primary anatomical risk factors are an insufficient medial patellofemoral ligament (MPFL), patella alta, trochlear dysplasia, increased distance from the tibial tuberosity to the trochlear groove (TTTG), and torsional limb parameters. Limitations of the Caton-Deschamps index are related to the clear identification of the patellar and tibial articular margin. Classification of trochlear dysplasia according to the Dejour system on radiographs and MR images revealed a weak reliability. The comparability of TTTG values obtained on CT and MR images at various flexion angles and different varus alignments of the knee is limited. Thus MRI performed with a dedicated knee coil may underestimate the TTTG distance compared with CT images. Increased lateral patellar tilt is a consequence of primary anatomical risk factors rather than an independent anatomical risk factor for patellar instability. The pretest likelihood of a torn MPFL on MR images is very high after an acute episode of lateral patellar dislocation. Surgical restoration of the patellofemoral joint stability addresses the complex multifactorial biomechanics by a custom-made management such as MPFL reconstruction, sulcus-deepening trochleoplasty, as well as medialization and distalization of the tibial tubercle. Quantification of anatomical risk factors for patellar instability in each person is important for highly individual treatment.

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Section: Tuberosity To the Trochlear Groove Distancementioning

confidence: 86%

Imaging of Individual Anatomical Risk Factors for Patellar Instability

Dietrich

Fucentese

Pfirrmann

2016

Semin Musculoskelet Radiol

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“…32 Furthermore, it has been shown that the TT-TG distance may change with leg position as the tibia rotates internally and externally with extension and flexion, making static imaging at a set flexion angle less useful. 34 Although the TT-TG distance has been correlated with symptoms, this can be highly variable. Whereas a distance greater than 15 mm on CT may be considered positive, patients with larger distances may be fairly asymptomatic and those with smaller distances may be symptomatic.…”

Section: Discussionmentioning

confidence: 99%

Clinical Utility of Continuous Radial Magnetic Resonance Imaging Acquisition at 3 T in Real-time Patellofemoral Kinematic Assessment: A Feasibility Study

Burke

Kaplan

Block

et al. 2018

Arthroscopy: The Journal of Arthroscopic & Related Surgery

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Purpose To compare patellar instability with magnetic resonance imaging analysis using continuous real-time radial gradient-echo (GRE) imaging in the assessment of symptomatic patients and asymptomatic subjects. Methods Symptomatic patients with suspected patellofemoral maltracking and asymptomatic volunteers were scanned in real time by a radial 2-dimensional GRE sequence at 3 T in axial orientation at the patella level through a range of flexion-extension. The degree of lateral maltracking, as well as the associated tibial tubercle–trochlear groove distance and trochlea depth, was measured. Patellar lateralization was categorized as normal (≤2 mm), mild (>2 to ≤5 mm), moderate (>5 to ≤10 mm), or severe (>10 mm). The patellofemoral cartilage was also assessed according to the modified Outerbridge grading system. Results The study included 20 symptomatic patients (13 women and 7 men; mean age, 36 ± 12.8 years) and 10 asymptomatic subjects (3 women and 7 men; mean age, 33.1 years). The mean time to perform the dynamic component ranged from 3 to 7 minutes. Lateralization in the symptomatic group was normal in 10 patients, mild in 1, moderate in 8, and severe in 1. There was no lateral tracking greater than 3 mm in the volunteer group. Lateral maltracking was significantly higher in symptomatic patients than in asymptomatic subjects (4.4 ± 3.7 mm vs 1.5 ± 0.71 mm, P = .007). Lateral tracking significantly correlated with tibial tubercle–trochlear groove distance (r = 0.48, P = .006). There was excellent agreement on lateral tracking between the 2 reviewers (intraclass correlation coefficient, 0.979; 95% confidence interval, 0.956-0.990). Conclusions The inclusion of a dynamic radial 2-dimensional GRE sequence is a rapid and easily performed addition to the standard magnetic resonance imaging protocol and allows dynamic quantitative assessment of patellar instability and lateral maltracking in symptomatic patients. With a paucity of reported data using this technique confirming that these results reach clinical significance, future work is required to determine how much lateral tracking is clinically significant. Level of Evidence Level III, case control.

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“…Our findings extend those of alignment studies in other patellofemoral pathologies such as patellofemoral pain or instability, and indicate that alignment in PF OA may be similar to that seen in these other populations. 18,19,21,22 In studies of patellofemoral pain or instability, under various conditions in terms of position and loading and across different knee flexion angles, lateral translation, lateral tilt, and proximal translation were greater compared to controls, with larger differences often seen in full extension. 19,20,40,41 Our results were similar, but did not show larger between-group differences in any measure in full extension.…”

Section: Discussionmentioning

confidence: 99%

“…Thus, it is clinically important to investigate between‐group differences in upright positions to determine how alignment behaves in functional positions. In the few upright MRI studies of patellofemoral pain or instability, alignment is worse compared to controls . It is unknown if similar findings exist in upright, weightbearing positions in PF OA.…”

mentioning

confidence: 99%

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Alignment differs between patellofemoral osteoarthritis cases and matched controls: An upright 3D MRI study

Macri

d’Entremont

Crossley

et al. 2019

Journal Orthopaedic Research

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Patellofemoral (PF) osteoarthritis (OA) is a prevalent and clinically important knee OA subgroup. Malalignment may be an important risk factor for PF OA. However, little is known about alignment in PF OA, particularly in an upright, weightbearing environment. Using a vertically‐oriented open‐bore MR scanner, we evaluated 3D knee alignment in 15 PF OA cases and 15 individually matched asymptomatic controls. We imaged one knee per participant while they stood two‐legged at four flexion angles (0°, 15°, 30°, 45°), and also while they stood one‐legged at 30° knee flexion. We calculated 3D patellofemoral and tibiofemoral alignment. Using mixed effects models, four of the five patellofemoral measures differed by group. For key measures, PF OA patellae were 6.6° [95%CI 5.0, 8.2] more laterally tilted, 2.4 mm [1.3, 3.5] more laterally translated, and at least 3.7 mm [0.2, 7.2] more proximally translated compared to controls (more with knees flexed). Alignment did not differ between two‐legged stance and one‐legged stance in either group. Statement of Clinical Significance: Our study demonstrated significant and clinically relevant differences in alignment between PF OA cases and controls in upright standing and squatting positions. Our findings were similar to those in previous studies of PF OA using traditional MR scanners in supine positions, supporting the clinical usefulness of existing methods aimed at identifying individuals who may benefit from interventions designed to correct malalignment. © 2019 The Authors. Journal of Orthopaedic Research ® Published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. 9999:1–9, 2019.

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Effects of upright weight bearing and the knee flexion angle on patellofemoral indices using magnetic resonance imaging in patients with patellofemoral instability

Cited by 35 publications

References 39 publications

Imaging of Individual Anatomical Risk Factors for Patellar Instability

Imaging of Individual Anatomical Risk Factors for Patellar Instability

Clinical Utility of Continuous Radial Magnetic Resonance Imaging Acquisition at 3 T in Real-time Patellofemoral Kinematic Assessment: A Feasibility Study

Alignment differs between patellofemoral osteoarthritis cases and matched controls: An upright 3D MRI study

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