Assessment of the reliability and validity of imaging measurements for patellofemoral instability: an updated systematic review

Geraghty, Liam; Humphries, David; Fitzpatrick, Jane

doi:10.1007/s00256-022-04110-9

Cited by 9 publications

(9 citation statements)

References 95 publications

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“…Along with magnetic resonance imaging (MRI) and X‐ray, computed tomography (CT) scans remain a standardized radiographic tool to assess and quantify patellofemoral alignment, showing good reliability [1, 11, 27, 48]. However, insufficient data for cutoff values or thresholds of anatomic factors based on CT images have been reported [18, 42]. Although demographic risk factors (e.g., age and sex) contribute to patellofemoral instability [5, 42], few previous studies have assessed patellofemoral morphology and anatomic risk factors within pair‐matched groups based on age and sex.…”

Section: Introductionmentioning

confidence: 99%

Sulcus depth, congruence angle, Wiberg index, TT-TG distance, and CDI are strong predictors of recurrent patellar dislocation

Chen

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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PurposeTo characterize patellofemoral morphology, determine radiological cutoff values based on computed tomography (CT) images, and clarify predominant anatomic risk factors in young patients with recurrent patellar dislocation (RPD). MethodsA total of 212 knees (age 23.0 ± 5.3 years, female: male = 110:102) with CT‐confirmed RPD were enrolled for analysis. The control group was matched by age and sex (2:1). Patellofemoral and trochlear morphology, patellofemoral alignment, and other parameters were assessed by CT. Standardized methods were used for measurements. Receiver operating characteristic (ROC) curves and the areas under the ROC curve (AUCs) were used to assess accuracy in diagnosing RPD. The index of union (IU) was employed to identify a cutoff value for risk. A binary logistic regression model (Forward, LR) was constructed, and standardized coefficients were calculated to compare the relative strength of different predictors. Factors included in the model were employed to calculate distributions in the studied population. ResultsThe majority of measurements showed a significant difference between the RPD and control groups when comparing mean values. The AUC value was favorable for sulcus depth and significantly better than that for other trochlear morphology parameters (P < 0.0001). Cutoff values were 0.58 for the Wiberg index, 153.3° for the sulcus angle, 3.6 mm for the sulcus depth, 1.94 for the trochlear width ratio, 16.2° for the lateral trochlear inclination, 17.2° for the patellar lateral tilt, 25.5° for the congruence angle, 1.2 for the patellar height [Caton–Deschamps index (CDI)], 6.1° for the knee rotation, and 16.4 mm for the tibial tubercle–trochlear groove (TT‐TG) distance. A binary logistic regression model (χ2 = 20.826, P = 0.008) including the Wiberg index, sulcus depth, congruence angle, patellar height (CDI), and TT‐TG distance was constructed for RPD (P ≤ 0.015), which showed excellent diagnostic performance, as indicated by an AUC of 0.989 (95% CI, 0.979 to 0.998). Sulcus depth showed the strongest relationship with RPD, followed by the congruence angle and Wiberg index, as indicated by the standardized coefficients − 1.43, 1.02, and 0.97, respectively. Eighty‐seven percent of the RPD population had sulcus depth ≤ 3.6 mm. ConclusionsThis study provides a systematic reference of cutoff values based on CT data. The combination of five anatomic risk factors (sulcus depth, congruence angle, Wiberg index, TT‐TG distance, and CDI) may be an excellent predictor of RPD as initial risk assessment. Sulcus depth, as the most frequently observed anatomic risk factor, showed the best diagnostic performance among trochlear morphological parameters and the strongest relationship with RPD, followed by the congruence angle and Wiberg index. In clinical practice, the sulcus depth, congruence angle, Wiberg index, TT‐TG distance, and CDI with the proposed cutoff values can be used in combination to evaluate RPD. When assessing trochlear morphology, sulcus depth is recommended as the best radi...

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Section: Introductionmentioning

confidence: 99%

Sulcus depth, congruence angle, Wiberg index, TT-TG distance, and CDI are strong predictors of recurrent patellar dislocation

Chen

et al. 2022

Knee Surg Sports Traumatol Arthrosc

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“…Lateral trochlear inclination, trochlear depth, and sulcus angle show good intra- and interobserver agreement. 20 Trochlear facet asymmetry, in contrast, shows poor to good intraobserver agreement. 20…”

Section: Anatomical Factors Predisposing To Patellar Instabilitymentioning

confidence: 99%

Patellar Instability: Imaging Findings

De Leeuw,

Abidi,

Scarciolla

et al. 2024

Semin Musculoskelet Radiol

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Patellofemoral instability results from impaired engagement of the patella in the trochlear groove at the start of flexion and may lead to pain and lateral patellar dislocation. It occurs most frequently in adolescents and young adults during sporting activities. Trochlear dysplasia, patella alta, and excessive lateralization of the tibial tuberosity are the most common risk factors for patellar instability. The main role of imaging is to depict and assess these anatomical factors and highlight features indicating previous lateral dislocation of the patella.

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“…31 The ideal imaging modality for each measurement is unknown, and the utility of originally described cutoff values across imaging modalities has not been validated. 13,36 On MRI scans, measurements utilizing bony versus cartilaginous landmarks are often performed interchangeably, despite evidence that they may differ in the evaluation of trochlear dysplasia. 33 Trochlear dysplasia has been more commonly reported in female patients, suggesting that increased anatomic risk factors may account for sex-specific differences in patellar instability.…”

Section: -In-5mentioning

confidence: 99%

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confidence: 99%

Redefining Trochlear Dysplasia: Normal Thresholds Vary by Measurement Technique, Landmarks, and Sex

et al. 2023

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Background: Trochlear dysplasia is a known risk factor for patellar instability. Multiple radiographic measurements exist to assess trochlear morphology, but the optimal measurement technique and threshold for instability are unknown. Purpose: To describe the optimal measurements and thresholds for trochlear dysplasia on magnetic resonance imaging (MRI) that can identify knees with patellar instability in male and female patients. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: Knee MRI scans of patients with patellar instability were compared with those of age- and sex-matched controls. Measurements of the sulcus angle, lateral trochlear inclination (LTI), and trochlear depth were performed on axial images using bony and cartilaginous landmarks. Receiver operating characteristic curve analysis was performed, with the area under the curve (AUC) describing the accuracy of each diagnostic test. Optimal cutoff values were calculated to distinguish between knees with and without patellar instability. AUC and cutoff values were reported for each measurement as well as for male and female subgroups. Results: A total of 238 knee MRI scans were included in this study (138 female, 100 male; age range, 18-39 years). Trochlear depth measurements had the greatest diagnostic value, with AUCs of 0.79 and 0.82 on bone and cartilage, respectively. All measurements (sulcus angle, LTI, trochlear depth) on bone and cartilage had an AUC ≥0.7 (range, 0.70-0.86), with optimal cutoff values of 145° (bone) and 154° (cartilage) for the sulcus angle, 17° (bone) and 13° (cartilage) for LTI, and 4 mm (bone) and 3 mm (cartilage) for trochlear depth. Optimal cutoff values in female patients varied from those in male patients for all measurements except for cartilaginous trochlear depth. Conclusion: Normal thresholds for trochlear dysplasia varied based on the use of bony versus cartilaginous landmarks. Cartilaginous trochlear depth measurements had the greatest ability to identify knees with patellar instability. Furthermore, optimal cutoff values for all measurements except for cartilaginous trochlear depth differed between female and male patients. These findings suggest that sex-specific parameters of normal values may be needed in the assessment of risk factors for patellofemoral instability.

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Assessment of the reliability and validity of imaging measurements for patellofemoral instability: an updated systematic review

Cited by 9 publications

References 95 publications

Sulcus depth, congruence angle, Wiberg index, TT-TG distance, and CDI are strong predictors of recurrent patellar dislocation

Sulcus depth, congruence angle, Wiberg index, TT-TG distance, and CDI are strong predictors of recurrent patellar dislocation

Patellar Instability: Imaging Findings

Redefining Trochlear Dysplasia: Normal Thresholds Vary by Measurement Technique, Landmarks, and Sex

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