Inter-rater reliability of TT-TG distance is good and does not vary based on preselected versus independent slice selection on MRI

2019 ◽  
Vol 4 (6) ◽  
pp. 302-305
Author(s):  
Corey Beals ◽  
David C Flanigan ◽  
Nicholas Peters ◽  
Walter Kim ◽  
Nicholas Early ◽  
...  
Keyword(s):  
Patellar Instability ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Level Of Evidence ◽  
Rater Reliability ◽  
Sulcus Angle ◽  
Intraclass Correlations ◽  
Good For ◽  
Active Patients ◽  
Axial Slice

ObjectivesPatellar instability is a frequent cause of knee dysfunction in young, active patients. Tibial tubercle–trochlear groove (TT-TG) distance, trochlear morphology (trochlear depth and sulcus angle) and patellar height are felt to contribute to patellar instability and may influence treatment. These measurements are frequently performed on MRI images. We hypothesised that inter-rater reliability of measures would be good and that inter-rater variation is driven primarily by slice selection.MethodsTwenty-six patients with at least one documented episode of patellar instability confirmed by MRI were identified. Six raters reviewed MRI images from each patient. Each rater measured and recorded TT-TG distance, trochlear depth and sulcus angle, and patellotrochlear index (PTI) for each patient and the slices used for the measurements. Each rater repeated the measurement using preselected slices. Inter-rater reliability was calculated by intraclass correlations (ICCs) for slice selection and for TT-TG distance, trochlear morphology measures and PTI with both independently selected and preselected slices. Statistically significant differences (p<0.05) in ICC based on slice selection were defined as values without overlap of their 95% CIs.ResultsInter-rater reliability was excellent for tibial (ICC=0.93) axial slice selection and sagittal slice selection (ICC=0.94), and good for femoral (ICC=0.88) axial slice selection. Using independent slice selection, inter-rater reliability was good for TT-TG distance (ICC=0.79) and fair for trochlear depth (ICC=0.57), sulcus angle (ICC=0.57) and PTI (ICC=0.71). When preselected slices were used, inter-rater reliability was good for TT-TG distance (ICC=0.85), sulcus angle (ICC=0.83) and PTI (ICC=0.77) and fair for trochlear depth (ICC=0.68). Only sulcus angle demonstrated a significant (p<0.05) improvement in inter-rater reliability with the use of preselected slices.Discussion and conclusionInter-rater reliability of TT-TG distance is good and does not vary based on preselected versus independent slice selection on MRI. Inter-rater reliability of trochlear morphology measures based on axial MRI slices and PTI is fair. Inter-rater variation can be reduced (particularly in the case of sulcus angle) through agreement on slice selection.Level of evidenceLevel III, diagnostic.

scholarly journals Identifying Patients With Patella Alta and/or Severe Trochlear Dysplasia Through the Presence of Patellar Apprehension in Higher Degrees of Flexion

2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092548
Author(s):  
Matthew Colatruglio ◽  
David C. Flanigan ◽  
Sarah Harangody ◽  
Robert A. Duerr ◽  
Christopher C. Kaeding ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Type B ◽  
Level Of Evidence ◽  
Sulcus Angle ◽  
Recurrent Patellar Instability

Background: Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle–trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as tibial tubercle osteotomy or trochleoplasty. The indications to perform such procedures are traditionally based on imaging criteria but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. Hypothesis: The persistence of patellar apprehension at greater than 60° of knee flexion is associated with patella alta, an increased TT-TG distance, and trochlear dysplasia. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 76 patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeatedly assessed as the knee was flexed in 10° intervals, as measured using a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain radiographs and magnetic resonance imaging (MRI) scans were obtained for all patients. Patellar height was assessed with the Caton-Deschamps (CD) index, and trochlear morphology was assessed through measurements of the sulcus angle and depth on MRI and classified using the Dejour classification system. Imaging measurements of patients in whom apprehension resolved by 60° of knee flexion were compared with measurements for those with apprehension that persisted deeper into flexion. Results: Apprehension resolved by 60° of flexion in 56 patients and persisted into deeper flexion in 20 patients. The patients with a delayed resolution of apprehension demonstrated a higher CD index; elevated TT-TG distance; increased sulcus angle; decreased sulcus depth; and higher incidence of Dejour type B, C, or D dysplasia (all P < .05). Of the 20 patients with a delayed resolution of apprehension, 18 had either Dejour type B, C, or D dysplasia or a CD index of at least 1.30. A delayed resolution of apprehension was present in 11 of the 16 patients with Dejour type B, C, or D dysplasia. Conclusion: Overall, 90% of patients with significant patella alta and the majority of patients with high-grade trochlear dysplasia demonstrated patellar apprehension that persisted beyond 60° of knee flexion. Additionally, 90% of patients with persistent apprehension had significant patella alta and/or trochlear dysplasia. Further work is needed to evaluate the utility of these findings to inform surgical decision-making in this population.

scholarly journals Increased tibial tubercle-trochlear groove and patellar height indicate a higher risk of recurrent patellar dislocation following medial reefing

2021 ◽  
Author(s):  
Marc-Daniel Ahrend ◽  
Tobias Eisenmann ◽  
Moritz Herbst ◽  
Boyko Gueorguiev ◽  
Gabriel Keller ◽  
...  
Keyword(s):  
Patellar Dislocation ◽  
Recurrent Dislocation ◽  
Patellar Height ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Recurrent Patellar Dislocation ◽  
Patellar Tilt ◽  
Level Of Evidence ◽  
Sulcus Angle ◽  
Patellar Shift

Abstract Purpose Identifying anatomical risk factors on recurrent dislocation after medial reefing is important for deciding surgical treatment. The present study aimed to retrospectively analyze the preoperative magnetic resonance imaging (MRI)-based parameters of patients treated with medial reefing and whether these parameters lead to a higher risk of recurrent dislocation. Methods Fifty-five patients (18.6 ± 6.6 years) who underwent medial reefing after primary traumatic patellar dislocation (84% with medial patellofemoral ligament [MPFL] rupture) were included. Patients were followed up for at least 24 months postoperatively (3.8 ± 1.2 years) to assess the incidence of recurrent patellar dislocation. In patients without recurrent dislocation, the Kujala and subjective IKDC scores were assessed. Moreover, the tibial tubercle-trochlear groove (TT-TG), sulcus angle, patellar tilt, patellar shift, and lateral trochlea index (LTI) were measured. The patellar height was measured using the Caton-Dechamps (CDI), Blackburne-Peel (BPI), and Insall-Salvati index (ISI). The cohort was subclassified into two groups with and without recurrent dislocation. Differences between groups were analyzed with respect to the MRI parameters. Results Forty percent had a pathological sulcus angle of > 145°, 7.2% had an LTI of < 11°, 47.3% had a patellar tilt of > 20°, and 36.4% had a TT-TG of ≥ 16 mm. Increased patellar height was observed in 34.5, 65.5, and 34.5% of the patients as per CDI, BPI, and ISI, respectively. Nineteen (34.5%) patients suffered from recurrent dislocation. Compared with patients without recurrent dislocation, those with recurrent dislocation had a significantly lower LTI (p = 0.0467). All other parameters were not significantly different between the groups. Risk factor analysis showed higher odds ratios (OR > 2), although not statistically significant, for MPFL rupture (OR 2.05 [95% confidence interval 0.38–11.03], LTI (6.6 [0.6–68.1]), TT-TG (2.9 [0.9–9.2]), and patellar height according to ISI (2.3 [0.7–7.5]) and CDI (2.3 [0.7–7.5])). Patients without recurrent dislocation had a Kujala score of 93.7 ± 12.1 (42–100) points and an IKDC score of 90.6 ± 11.7 (55.2–100) points. Conclusion Anatomical, MRI-based parameters should be considered before indicating medial reefing. A ruptured MPFL, an LTI < 11°, a TT-TG ≥ 16 mm, a patellar tilt > 20 mm, and an increased patellar height according to ISI and CDI were found to be associated, although not significantly, with a higher risk (OR > 2) of recurrent patellar dislocation after medial reefing. Thorough preoperative analysis is crucial to reduce the risk of recurrent dislocation in young patient cohorts. Level of evidence Level IV

scholarly journals ASSOCIATION BETWEEN RADIOGRAPHIC PARAMETERS AND OSTEOCHONDRAL DAMAGE IN PATIENTS WITH PATELLAR INSTABILITY

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0048
Author(s):  
Lilah Fones ◽  
Regina Kostyun ◽  
James Pace
Keyword(s):  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Odds Ratios ◽  
Sulcus Angle ◽  
Radiographic Parameters ◽  
Radiographic Measurements ◽  
Patient Reported ◽  
Adolescent Patients

Objectives: Osteochondral damage is a potential consequence of patellar instability that is associated with an increased risk of arthritis and lower patient reported outcomes. Currently, there is little evidence of risk factors associated with osteochondral damage in the setting of patellar instability. The purpose of this study was to identify the association of patient demographics, chronicity of patellar instability, and radiographic measurements with osteochondral damage in adolescent patients with patellar instability. Methods: Upon obtaining Institutional Review Board approval, a chart review was conducted to identify patients 18 years of age and younger treated for patellar instability between 2013 and 2018 at a tertiary referral center. Patients with both acute traumatic and chronic recurrent dislocations with magnetic resonance imaging (MRI) results available were included. Patients were excluded if they had a previous ipsilateral patellar instability surgical intervention. MRI exams were reviewed, and measurements were conducted for Caton-Deschamps (CD) ratio, proximal tibial tubercle to trochlear groove (pTT-TG), distal tibial tubercle to trochlear groove (dTT-TG), lateral trochlear inclination (LTI), lateral patellar inclination (LPI), and sulcus angle. Logistical regression was conducted using binary outcome of presence or absence of osteochondral damage (Statistical Analysis Software, Cary, NC). Odds ratios were calculated for parameters that were statistically significant (p<0.05). Results: A total of 129 knees and 122 patients (average age at first visit 14.4±3.0, 51% female) were identified with patellar instability, of which 53% had osteochondral damage. Approximately one third of patients (67%) were treated with surgical management. There was no association identified between osteochondral damage and sex, age, BMI, symptom duration, physeal status, or number of dislocation (acute vs chronic). Of the radiographic measurements evaluated, LTI, LPI, sulcus angle and dTT-TG all had a statistically significant association with the presence of osteochondral damage (Table 1). Every 1-unit decrease in LTI (more trochlear dysplasia) was associated with a 6% increased chance of osteochondral damage. Every 1-unit increase in LPI, sulcus angle, and dTT-TG is associated with an increased chance of osteochondral damage of 5.5%, 5.8%, and 11.3%, respectively. The CD ratio and pTT-TG had no association with osteochondral damage. Confidence intervals, p-values, and odds ratios are presented in Table 1. Conclusions: There is an association between radiographic parameters, particularly those that correlate with higher levels of trochlear dysplasia, and osteochondral damage in adolescent patients with patellar instability, but no association with being either an acute or chronic dislocator. Clinically, this may impact the management of patients presenting with patellar instability and no radiographic evidence of osteochondral damage. In these patients, clinicians may have a lower threshold for surgical interventions in those with higher levels of trochlear dysplasia as evidenced by decreased LTI and an increased LPI, sulcus angle, and dTT-TG.

Bisect offset ratio and cartilaginous sulcus angle are good combined predictors of recurrent patellar dislocation in children and adolescents

2021 ◽  
pp. jisakos-2020-000461
Author(s):  
Sheanna Maine ◽  
Christina Ngo-Nguyen ◽  
Martina Barzan ◽  
Chris Stockton ◽  
Luca Modenese ◽  
...  
Keyword(s):  
Patellar Dislocation ◽  
Trochlear Dysplasia ◽  
Pediatric Population ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Recurrent Patellar Dislocation ◽  
Patellar Tilt ◽  
Level Of Evidence ◽  
Femoral Torsion ◽  
Sulcus Angle

ObjectivesRecurrent patellar dislocation (RPD) is found most commonly in the juvenile population. While risk factors have been well-established in adults, there remains a paucity in radiographical data to define normal and pathoanatomical juvenile cohorts. The objectives of this paper were to elucidate the differences in the patellofemoral joint between RPD and typically developed (TD) juvenile populations, using MRI measurements, and determine the best independent and combined predictors of RPD.MethodsA prospective, cross-sectional study was conducted with 25 RPD and 24 TD participants aged between 8 and 19 years. MR images were obtained to assess common measures of lower limb alignment, patellofemoral alignment, and trochlear dysplasia.ResultsSignificant differences were evident for acetabular inclination, tibial-femoral torsion, tibial tubercle-to-trochlear groove (TT-TG) distance, lateral patellar tilt (LPT), cartilaginous sulcus angle (CSA) and bisect offset ratio (BOR). CSA and BOR were included in the final predictive model, which correctly classified 89.4% of RPD cases.ConclusionRadiographical parameters that stratify risk of RPD in adults are also able to predict RPD in the pediatric population (TT-TG, LPT, CSA and BOR). Together, CSA and BOR accurately identified 89.4% of RPD. These measures should be included in the evaluation of pediatric patients who present with patellar dislocation.Level of evidenceLevel II.

scholarly journals The Presence of Patellar Apprehension in Higher Degrees of Flexion Identifies Patients with Patella Alta and or Severe Trochlear Dysplasia

2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0034
Author(s):  
Matthew Colatruglio ◽  
David Flanigan ◽  
Sarah Harangody Robert Magnussen
Keyword(s):  
Sports Medicine ◽  
Knee Flexion ◽  
Patellar Instability ◽  
Trochlear Dysplasia ◽  
Patella Alta ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Sulcus Angle ◽  
Plain Films ◽  
Recurrent Patellar Instability

Objectives: Recurrent patellar instability is frequently treated surgically with reconstruction of the medial patellofemoral ligament (MPFL). Patients with significant patella alta, trochlear dysplasia, and/or an elevated tibial tubercle-trochlear groove (TT-TG) distance may benefit from a concurrent bony procedure such as a tibial tubercle osteotomy or trochleoplasty. The indications to include such procedures are traditionally based on imaging criteria, but remain controversial. Patellar apprehension is common in patients with patellar instability but typically resolves in higher degrees of knee flexion. We hypothesis that the persistence of patellar apprehension at greater than 60 degrees of knee flexion is associated with patella alta, increased TT-TG distance, and trochlear dysplasia. Methods: Seventy-six patients with recurrent patellar instability were prospectively identified in a sports medicine clinic. Patellar apprehension was evaluated in each patient. Apprehension was defined as the patient reporting that the patella felt unstable to lateral patellar translation. Apprehension was first assessed at full knee extension and repeated assessed as the knee was flexed in 10 degrees intervals as measured with a goniometer. The degree of flexion at which patellar apprehension disappeared was recorded. Plain films and MRI were obtained in all patients. Patellar height was assessed with the Caton-Deschamps (CD) index and trochlear morphology was assessed through measurement of the sulcus angle and depth on MRI and classification with the Dejour classification system. Imaging measurements of patients in which apprehension resolved by 60 degrees of knee flexion were compared with measures for those with apprehension that persisted deeper into flexion. Results: Apprehension resolved by 60 degrees of flexion in 55 patients and persisted into deeper flexion in 21 patients. The patients with delayed resolution of apprehension demonstrated a higher CD Index, elevated TT-TG distance, increased higher sulcus angle, decreased trochlear depth, and a higher incidence of Dejour B, C, or D dysplasia (all p < 0.05, Table 1). Of the 21 patients with delayed resolution of apprehension, 18 had either Dejour B, C, or D dysplasia or a Caton-Deschamps Index of at least 1.3. Delayed resolution of apprehension was present in 11 of the 16 patients with Dejour B, C, or D dysplasia. Conclusion: The presence of patellar apprehension in higher degrees of knee flexion is associated with patella alta, increased TT-TG distance, and more severe trochlear dysplasia. Further work is needed to evaluate utility of this exam finding to inform surgical decision-making in this population.

scholarly journals Comparing the Tibial Tuberosity–Trochlear Groove Distance Between CT and MRI in Skeletally Immature Patients With and Without Patellar Instability

2021 ◽  
Vol 9 (1) ◽  
pp. 232596712097366
Author(s):  
Zhen-Zhen Dai ◽  
Lin Sha ◽  
Zi-Ming Zhang ◽  
Zhen-Peng Liang ◽  
Hao Li ◽  
...  
Keyword(s):  
Patellar Instability ◽  
Intraclass Correlation ◽  
Mean Difference ◽  
Tibial Tubercle ◽  
Control Group ◽  
Trochlear Groove ◽  
Skeletally Immature ◽  
Bony Landmarks ◽  
The Difference ◽  
Ct And Mri

Background: The tibial tubercle–trochlear groove (TT-TG) distance was originally described for computed tomography (CT), but it has been measured on magnetic resonance imaging (MRI) in patients with patellar instability (PI). Whether the TT-TG measured on CT versus MRI can be considered equivalent in skeletally immature children remains unclear. Purpose: To investigate in skeletally immature patients (1) the effects of CT versus MRI imaging modality and cartilage versus bony landmarks on consistency of TT-TG measurement, (2) the difference between CT and MRI measurements of the TT-TG, and (3) the difference in TT-TG between patients with and without PI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We retrospectively identified 24 skeletally immature patients with PI and 24 patients with other knee disorders or injury but without PI. The bony and cartilaginous TT-TG distances on CT and MRI were measured by 2 researchers, and related clinical data were collected. The interrater, interperiod (bony vs cartilaginous), and intermethod (CT vs MRI) reliabilities of TT-TG measurement were assessed with intraclass correlation coefficients. Results: The 48 study patients (19 boys, 29 girls) had a mean age of 11.3 years (range, 7-14 years). TT-TG measurements had excellent interrater reliability and good or excellent interperiod reliability but fair or poor intermethod reliability. TT-TG distance was greater on CT versus MRI (mean difference, 4.07 mm; 95% CI, 2.6-5.5 mm), and cartilaginous distance was greater than bony distance (mean difference, 2.3 mm; 95% CI, 0.79-3.8 mm). The TT-TG measured on CT was found to increase with the femoral width. Patients in the PI group had increased TT-TG distance compared with those in the control group, regardless of landmarks or modality used ( P > .05 for all). Conclusion: For skeletally immature patients, the TT-TG distance could be evaluated on MRI, regardless of whether cartilage or bony landmarks were used. Its value could not be interchanged with CT according to our results; however, further research on this topic is needed.

scholarly journals SPONTANEOUS CORRECTION OF EXTERNAL TIBIOFEMORAL ROTATION AND TIBIAL TUBEROSITY-TROCHLEAR GROOVE DISTANCE OCCURS AFTER MEDIAL PATELLOFEMORAL LIGAMENT RECONSTRUCTION IN FIXED OR OBLIGATORY DISLOCATORS

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0013
Author(s):  
Alexandra H. Aitchison ◽  
Kenneth M. Lin ◽  
Daniel W. Green
Keyword(s):  
Patellar Instability ◽  
Ligament Reconstruction ◽  
Medial Patellofemoral Ligament ◽  
Extensor Mechanism ◽  
Tibial Tubercle ◽  
Trochlear Groove ◽  
Medial Patellofemoral Ligament Reconstruction ◽  
Force Vector ◽  
Tibiofemoral Rotation ◽  
The Mean

Background: Tibial tubercle to trochlear groove distance (TT-TG) and external tibiofemoral rotation (TFR) through the knee joint have been identified potential contributing factors to patellar instability. In patients with a fixed or obligatory lateral patella dislocation (FOD), the normal force vector of the extensor mechanism is altered, so instead of a direct axial pull to cause extension, it exerts a lateralizing and external rotatory force on the tibia via the tibial tubercle. Hypothesis/Purpose: The purpose of this study is to investigate postoperative changes in TT-TG and TFR after medial patellofemoral ligament reconstruction (MPFLR) in two clinical cohorts: standard traumatic patellar instability (SPI) patients and FOD patients. We hypothesized that by surgically relocating the patella in the trochlea, and re-establishing medial sided soft tissue tension, the increased medializing force vector on the patella may exert enough force to alter resting rotation of the tibia in relation to the femur in the FOD group. Methods: A retrospective study was performed from April 2009 to February 2019. FOD and SPI patients under 18 years with available magnetic resonance imaging (MRI) of the knee before and after MPFLR were eligible. All FOD patients in the time frame were analyzed and SPI patients were randomly selected. Exclusion criteria were outside institution MRI, concomitant alignment procedures done at the time of MPFLR, and prior MPFLR or tibial tubercle osteotomy. TT-TG and TFR (using the posterior femoral and tibial condylar lines) were measured blindly on initial axial MRI. Statistical analysis using a paired sample t-test was performed with significance set at p<0.05. Results: A total of 30 patients were included, 14 in the FOD group and 16 in the SPI group. The mean age at time of surgery was 13.9 years (range 10-17 years), 53% of the cohort was female, and the mean time from surgery to follow-up MRI was 2.0 years. Demographics by group are shown in Table 1. TT-TG and TFR were not significantly different preoperatively versus postoperatively in the SPI group (Table 2). In the FOD group, both TT-TG (17.7 vs 13.7, P=.019) and TFR (8.6 vs 3.1, P=.025) decreased significantly on postoperative MRI. Conclusion: The postoperative decrease in TT-TG and TFR in the FOD group suggests that MPFLR in fixed or obligatory dislocators can improve the external rotation deformity through the level of the joint, and thus may help normalize the forces acting through the extensor mechanism. Tables/ Figures [Table: see text][Table: see text]

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