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

Author(s):  
Sheanna Maine ◽  
Christina Ngo-Nguyen ◽  
Martina Barzan ◽  
Chris Stockton ◽  
Luca Modenese ◽  
...  

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.

Author(s):  
Marc-Daniel Ahrend ◽  
Tobias Eisenmann ◽  
Moritz Herbst ◽  
Boyko Gueorguiev ◽  
Gabriel Keller ◽  
...  

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


2020 ◽  
Vol 8 (6) ◽  
pp. 232596712092548
Author(s):  
Matthew Colatruglio ◽  
David C. Flanigan ◽  
Sarah Harangody ◽  
Robert A. Duerr ◽  
Christopher C. Kaeding ◽  
...  

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.


2018 ◽  
Vol 100-B (6) ◽  
pp. 811-821 ◽  
Author(s):  
K. Fu ◽  
G. Duan ◽  
C. Liu ◽  
J. Niu ◽  
F. Wang

Aims The aim of this study was to investigate the changes in femoral trochlear morphology following surgical correction of recurrent patellar dislocation associated with trochlear dysplasia in children. Patients and Methods A total of 23 patients with a mean age of 9.6 years (7 to 11) were included All had bilateral recurrent patellar dislocation associated with femoral trochlear dysplasia. The knee with traumatic dislocation at the time of presentation or that had dislocated most frequently was treated with medial patellar retinacular plasty (Group S). The contralateral knee served as a control and was treated conservatively (Group C). All patients were treated between October 2008 and August 2013. The mean follow-up was 48.7 months (43 to 56). Axial CT scans were undertaken in all patients to assess the trochlear morphological characteristics on a particular axial image which was established at the point with the greatest epicondylar width based on measurements preoperatively and at the final follow-up. Results Preoperatively, there were no statistically significant differences between the trochlear morphology in the two groups (sulcus angle, p 0.852; trochlear groove depth, p 0.885; lateral trochlear inclination, p 0.676; lateral-to-medial facet ratio, p 0.468; lateral condylar height, p 0.899; medial condylar height, p 0.816). Many radiological parameters of trochlear morphology were significantly different between the two groups at the final follow-up, including well-known parameters, such as the mean sulcus angle (Group S, 146.27° (sd 7.18); Group C, 160.61° (sd 9.29); p < 0.001), the mean trochlear groove depth (Group S, 6.25 mm (sd 0.41); Group C, 3.48 mm (sd 0.65); p < 0.001) and the mean lateral trochlear inclination (Group S, 20.99° (sd 3.87); Group C, 12.18° (sd 1.85); p < 0.001). Lesser known parameters such as the ratio of the lateral to medial trochlear length (Group S, 1.46 (sd 0.19); Group C, 2.14 (sd 0.42); p < 0.001), which is a measurement of facet asymmetry, and the lateral and medial condylar height were also significantly different between the two groups (p < 0.001). Conclusion The femoral trochlear morphology can be improved by early (before epiphyseal closure) surgical correction in children with recurrent patellar dislocation associated with femoral trochlear dysplasia. Cite this article: Bone Joint J 2018;100-B:811–21.


2020 ◽  
Vol 8 (4) ◽  
pp. 232596712091487 ◽  
Author(s):  
Zijie Xu ◽  
Hua Zhang ◽  
Binjie Fu ◽  
Sheikh Ibrahimrashid Mohamed ◽  
Jian Zhang ◽  
...  

Background: The surgical indication for tibial tubercle osteotomy (TTO) has been based on a tibial tubercle–trochlear groove (TT-TG) distance of 20 mm or greater in patients with patellar dislocation. However, the measurement of this parameter is less reliable in patients with trochlear dysplasia. Hypothesis: The novel measurement of tibial tubercle–Roman arch (TT-RA) distance would be a reliable parameter for identifying the relative position of the tibial tubercle in patients with patellar dislocation, especially those with trochlear dysplasia. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 56 patients with a diagnosis of patellar dislocation and 60 volunteers (60 knee joints) without a history of lower extremity pain or injury were included in our study. The TT-RA distance, TT-TG distance, and some femoral anatomic parameters were assessed by use of computed tomography. The measurements were performed by a radiologist and an orthopaedic surgeon in a blinded and randomized fashion. The difference in each parameter between the study and control groups was analyzed through use of an unpaired t test. Receiver operating characteristic curve analysis was performed to evaluate the discriminatory capacity of the included parameters. The cutoff values of the included measurements with specificity and sensitivity were calculated. In addition, the TT-TG distance and TT-RA distance were analyzed using the Dejour classification to evaluate the intraclass correlation coefficient (ICC) of each parameter in different types of femoral trochlea. Result: A significant difference for TT-RA distance was found between the study group (23.24 ± 4.41 mm) and control group (19.15 ± 4.24 mm) ( P < .001). The TT-RA distance had an area under the curve of 0.757. At a value greater than 23.74 mm, TT-RA distance had 53.57% sensitivity and 88.33% specificity for patellar dislocation. The ICCs of TT-RA distance measurements were excellent in all Dejour classifications (>0.939), whereas the ICCs of TT-TG distance measurements were relatively lower than the ICCs of TT-RA distance measurements. According to the data from included healthy individuals, the pathological TT-RA distance threshold was 26 mm. Conclusion: Compared with TT-TG distance, the TT-RA distance is a more reliable parameter for identifying the relative position of the tibial tubercle in patients with trochlear dysplasia. For patients with a TT-RA distance greater than 26 mm, surgery should be considered to correct the malposition of the tibial tubercle.


2017 ◽  
Vol 31 (05) ◽  
pp. 425-432 ◽  
Author(s):  
Ran Xiong ◽  
Cheng Chen ◽  
Li Yin ◽  
Xiaoyuan Gong ◽  
Jiangming Luo ◽  
...  

AbstractThe purpose of this study was to detect the correlation between axial scan orientation discrepancy and the knee anatomical parameters associated with patellofemoral instability during computed tomography (CT) scanning. CT scan data of 16 knees from 16 healthy subjects were retrieved. The reslicing processes were performed to simulate different axial scan orientations generated due to leg adduction/abduction during CT scanning. Eight parameters (tibial tubercle to trochlear groove [TT-TG], tibial tubercle to posterior cruciate ligament [TT-PCL], patellar tilt, lateral trochlear inclination, sulcus angle, trochlear depth, trochlear facet asymmetry, and trochlear condyle asymmetry) of five angles (neutral zero, 4/8 degrees of adduction and 4/8 degrees abduction) were quantified. All eight parameters showed varying degrees of deviations to the different axial scan orientations. TT-TG, patellar tilt, lateral trochlear inclination, and trochlear condyle asymmetry were relatively sensitive to axial scan orientation changes, whereas TT-PCL, sulcus angle, trochlear depth, and trochlear facet asymmetry were relatively insensitive. Although the sensitivities are various, surgeons should be aware of this situation and make necessary corrections.


Author(s):  
Corey Beals ◽  
David C Flanigan ◽  
Nicholas Peters ◽  
Walter Kim ◽  
Nicholas Early ◽  
...  

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.


2021 ◽  
Author(s):  
Yike Dai ◽  
Heyong Yin ◽  
Chongyang Xu ◽  
Hongrui Zhang ◽  
Ai Guo ◽  
...  

Abstract Background: Risk factors for the progression of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.Methods: A retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic severity of PFOA and tibiofemoral OA (TFOA), lateral and medial trochlear inclination angle, sulcus angle and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG), patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters and the relationship between each measure and the severity of PFOA was investigated.Results: By studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P <0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle, and type I patella was 8.80 (p=0.043), 16.51 (P <0.001), 0.04(P <0.001), and 0.18 (p=0.048) respectively.Conclusions: Extreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.


2020 ◽  
Vol 8 (7_suppl6) ◽  
pp. 2325967120S0048
Author(s):  
Lilah Fones ◽  
Regina Kostyun ◽  
James Pace

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.


2019 ◽  
Vol 47 (10) ◽  
pp. 2444-2453 ◽  
Author(s):  
Luiz Felipe Ambra ◽  
Betina B. Hinckel ◽  
Elizabeth A. Arendt ◽  
Jack Farr ◽  
Andreas H. Gomoll

Background:Focal cartilage lesions in the patellofemoral (PF) joint are common. Several studies correlated PF risk factors with PF instability, anterior knee pain, and PF arthritis; however, there is a lack of evidence correlating those factors to PF focal cartilage lesions.Purpose:To evaluate the influence of the anatomic PF risk factors in patients with isolated focal PF cartilage lesions.Study Design:Cross-sectional study; Level of evidence, 3.Methods:Patients with isolated PF focal cartilage lesions were included in the cartilage lesion group, and patients with other pathologies and normal PF cartilage were included in the control group. Multiple PF risk factors were accessed on magnetic resonance imaging scans: patellar morphology (patellar width, patellar thickness, and patellar angle), trochlear morphology (trochlear sulcus angle, lateral condyle index, and trochlear sulcus depth), patellar height (Insall-Salvati ratio and Caton-Deschamps index), axial patellar positioning (patellar tilt, angle of Fulkerson), and quadriceps vector (tibial tuberosity–trochlear groove distance).Results:A total of 135 patients were included in the cartilage lesion group and 100 in the control group. As compared with the control group, the cartilage lesion group had a higher sulcus angle ( P = .0007), lower trochlear sulcus depth ( P < .0001), lower angle of Fulkerson ( P < .0001), lower patellar width ( P = .0003), and higher Insall-Salvati ratio ( P < .0001). From the patients in the cartilage lesion group, 36% had trochlear dysplasia; 27.6%, patella alta; and 24.7%, abnormal patellar tilt. These parameters were more frequent in the cartilage lesion group ( P < .0001). Trochlear lesions were more frequent in men, presented at an older age, and had fewer associated anatomic risk factors. Patellar lesions, conversely, were more frequent in women, presented at younger age, and were more closely associated with anatomic risk factors.Conclusion:PF anatomic abnormalities are significantly more common in patients with full-thickness PF cartilage lesions. Trochlear dysplasia, patella alta, and excessive lateral patellar tilt are the most common correlated factors, especially in patellar lesions.


2018 ◽  
Vol 6 (2) ◽  
pp. 29-36 ◽  
Author(s):  
Alexander A. Sautenko ◽  
Egor V. Ogarev ◽  
Alexander G. Eltsin ◽  
Vladimir N. Merkulov ◽  
Dmitry S. Mininkov

Background. Patellar instability is a common problem in pediatric patients. Up to 2%–3% of all knee injuries are associated with acute patellar dislocation. According to the data in the literature, patients aged 10–17 years are at the highest risk of patellar dislocation and subsequent instability. These patients must be evaluated according to the proposed algorithm to select the optimal treatment method. Aim. To diagnose patellar instability in children and subsequently select the optimal treatment method based on acquired data. Materials and methods. The study is based on data acquired through the examination and treatment of 147 patients at the 9th Department of Pediatric Traumatology and Orthopedics. Great emphasis was put on computed tomography (CT) data, its essential parameters, which require the most thorough analysis, and assessment methods. These parameters include patellar tilt, dysplasia of the distal metaepiphysis of the femur, the tibial tubercle–trochlear groove index, and the rotational relation of the femur and tibia. Results. A novel algorithm for patient examination using CT is proposed. Data obtained by multislice CT (MSCT) had a significant influence on the selection of the surgical method for treating patients with patellar instability. Conclusion. The examination of patients with patellar instability using MSCT in adherence to the proposed diagnostic algorithm allows the selection of the optimal treatment method, which will increase the likelihood of rapid recovery of patients and their return to the level of activity similar to that before injury.


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