MRI Evaluation of Trochlear Dysplasia as a Cause of Patellar Instability

Objectives: In this study, we have attempted to evaluate the predisposing factors of patellar instability on magnetic resonance imaging (MRI) and to compare the significance of measurement at the level of trochlear bone versus cartilage for trochlear dysplasia. Material and Methods: Thirty patients of patellar instability were assessed on MRI for risk factors of patellar instability including trochlear dysplasia, tibial tuberosity to trochlear groove (TT-TG) distance, and patellar height ratio. Results: Twenty-one (70%) and 27 (90%) cases were positive for decreased trochlear depth when measured at the level of trochlear bone and cartilage, respectively. Eighteen (60%) and 25 (83.33%) cases were positive for trochlear facet asymmetry when measured at trochlear bone and cartilage, respectively. Twelve cases (40 %) were positive for patella alta. Ten cases (33.33%) were positive for decreased lateral trochlear inclination. Seven cases (23.3%) had increased TT to TG distance. Twenty-four cases (80%) were of age equal to or <25 years. Conclusion: According to our study, trochlear dysplasia is the most common predisposing factor of patellar instability (100%) followed by patella alta (40%) and TT-TG distance (23.3%). Trochlear depth and facet asymmetry produce better results as a predisposing factor for instability of patella when measured at the level of trochlear cartilage as compared to trochlear bone with P = 0.001.

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Relationship between Anatomical Risk Factors, Articular Cartilage Lesions, and Patient Outcomes Following Medial Patellofemoral Ligament Reconstruction

Cartilage ◽

10.1177/1947603519894728 ◽

2019 ◽

pp. 194760351989472 ◽

Cited By ~ 4

Author(s):

Charles L. Holliday ◽

Laurie A. Hiemstra ◽

Sarah Kerslake ◽

John A. Grant

Keyword(s):

Risk Factors ◽

Odds Ratio ◽

Patellar Instability ◽

Ligament Reconstruction ◽

Medial Patellofemoral Ligament ◽

Trochlear Dysplasia ◽

Cartilage Lesion ◽

Low Grade ◽

Medial Patellofemoral Ligament Reconstruction ◽

Cartilage Lesions

Objective The purpose of this study was (1) to determine which risk factors for patellar instability were associated with the presence of patellofemoral cartilage lesions and (2) to determine how cartilage lesion presence, size, and grade affect postoperative disease-specific quality of life. Design Preoperative, intraoperative, and postoperative demographic, anthropometric (body mass index, Beighton score, hip rotation), radiographic (crossover sign, trochlear bump), cartilage lesion morphology (presence, size, location, grade), and outcomes data (Banff Patella Instability Instrument 2.0 [BPII 2.0]) were prospectively collected from patients undergoing isolated medial patellofemoral ligament reconstruction. For all knees ( n = 264), single and multivariable logistic regression was used to determine if any patellar instability risk factors affected the odds of having a cartilage lesion. In patients with unilateral symptoms ( n = 121), single variable linear regression was used to determine if the presence, size, or ICRS (International Cartilage Regeneration & Joint Preservation Society) grade of cartilage lesions could predict the 12 or 24+ month postoperative BPII 2.0 score. Results A total of 84.5% of knees had patellofemoral cartilage lesions (88.3% involved the distal-medial patella). Trochlear dysplasia (high grade: odds ratio = 15.7, P < 0.001; low grade: odds ratio = 2.9, P = 0.015) was associated with the presence of a cartilage lesion. The presence, size, and grade of cartilage lesions were not associated with 12 or 24+ month postoperative BPII 2.0 scores. Conclusions Trochlear dysplasia was a risk factor for the development of patellofemoral cartilage lesions in this patient population. Cartilage lesions most commonly involve the distal-medial patella. There was no significant relationship between patellofemoral cartilage lesion presence, size, or grade and postoperative BPII 2.0 scores in short-term follow-up.

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Trochleaplasty for patellar instability due to trochlear dysplasia

Acta Orthopaedica ◽

10.1080/17453670510041781 ◽

2005 ◽

Vol 76 (5) ◽

pp. 693-698 ◽

Cited By ~ 130

Author(s):

Philip B Schöttle ◽

Sandro F Fucentese ◽

Christian Pfirrmann ◽

Heinz Bereiter ◽

Jose Romero

Keyword(s):

Patellar Instability ◽

Trochlear Dysplasia

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Recession wedge trochleoplasty as an additional procedure in the surgical treatment of patellar instability with major trochlear dysplasia: Early results

Orthopaedics & Traumatology Surgery & Research ◽

10.1016/j.otsr.2011.07.013 ◽

2011 ◽

Vol 97 (8) ◽

pp. 833-845 ◽

Cited By ~ 53

Author(s):

M. Thaunat ◽

C. Bessiere ◽

N. Pujol ◽

P. Boisrenoult ◽

P. Beaufils

Keyword(s):

Surgical Treatment ◽

Patellar Instability ◽

Trochlear Dysplasia ◽

Early Results ◽

Additional Procedure

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Clinical validation of the Oswestry-Bristol Classification as part of a decision algorithm for trochlear dysplasia surgery

The Bone & Joint Journal ◽

10.1302/0301-620x.103b10.bjj-2020-1984.r1 ◽

2021 ◽

Vol 103-B (10) ◽

pp. 1586-1594

Author(s):

Nikhil Sharma ◽

Nader Rehmatullah ◽

Jan Herman Kuiper ◽

Peter Gallacher ◽

Andrew J. Barnett

Keyword(s):

Treatment Group ◽

Complication Rate ◽

Patellar Instability ◽

Assessment Tool ◽

Trochlear Dysplasia ◽

International Knee Documentation Committee ◽

Tibial Tubercle ◽

Decision Algorithm ◽

Additional Surgery ◽

Five Dimension

Aims The Oswestry-Bristol Classification (OBC) is an MRI-specific assessment tool to grade trochlear dysplasia. The aim of this study is to validate clinically the OBC by demonstrating its use in selecting treatments that are safe and effective. Methods The OBC and the patellotrochlear index were used as part of the Oswestry Patellotrochlear Algorithm (OPTA) to guide the surgical treatment of patients with patellar instability. Patients were assigned to one of four treatment groups: medial patellofemoral ligament reconstruction (MPFLr); MPFLr + tibial tubercle distalization (TTD); trochleoplasty; or trochleoplasty + TTD. A prospective analysis of a longitudinal patellofemoral database was performed. Between 2012 and 2018, 202 patients (233 knees) with a mean age of 24.2 years (SD 8.1), with recurrent patellar instability were treated by two fellowship-trained consultant sports/knee surgeons at The Robert Jones and Agnes Hunt Orthopaedic Hospital. Clinical efficacy of each treatment group was assessed by Kujala, International Knee Documentation Committee (IKDC), and EuroQol five-dimension questionnaire (EQ-5D) scores at baseline, and up to 60 months postoperatively. Their safety was assessed by complication rate and requirement for further surgery. The pattern of clinical outcome over time was analyzed using mixed regression modelling. Results In all, 135 knees (mean age 24.9 years (SD 9.4)) were treated using a MPFLr. Ten knees (7.4%) required additional surgery. A total of 50 knees (mean age 24.4 years (SD 6.3)) were treated using MPFLr + TTD. Ten (20%) required additional surgery. A total of 20 knees (mean age 19.5 years (SD 3.0)) were treated using trochleoplasty + TTD. Three patients (15%) required additional surgery. In each treatment group, there was a significant improvement in Kujala, IKDC, and EQ-5D at one year postoperatively (p < 0.001) with a recognized level of overall complication rate. Conclusion The OBC is a valid assessment tool to grade patients with trochlear dysplasia and, when used as part of the OPTA, helps to determine treatments that are safe and effective. This fulfils the requirements for its application in mainstream clinical practice. Cite this article: Bone Joint J 2021;103-B(10):1586–1594.

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Combined patellofemoral arthroplasty and medial patellofemoral ligament reconstruction for chronic patellar instability with trochlear dysplasia: a report of two cases

Modern Rheumatology Case Reports ◽

10.1080/24725625.2019.1638048 ◽

2019 ◽

Vol 4 (1) ◽

pp. 135-140

Author(s):

Ryota Yamagami ◽

Hiroshi Inui ◽

Shuji Taketomi ◽

Sakae Tanaka

Keyword(s):

Patellar Instability ◽

Ligament Reconstruction ◽

Medial Patellofemoral Ligament ◽

Trochlear Dysplasia ◽

Medial Patellofemoral Ligament Reconstruction ◽

Patellofemoral Arthroplasty

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RISK FACTORS FOR PATELLAR INSTABILITY USING A QUANTITATIVE ANALYSIS OF TROCHLEAR DYSPLASIA

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00344 ◽

2020 ◽

Vol 8 (7_suppl6) ◽

pp. 2325967120S0034

Author(s):

Jon Hedgecock ◽

Christopher Cheng ◽

Matthew Solomito ◽

James Pace

Keyword(s):

Risk Factors ◽

Risk Factor ◽

Roc Curve ◽

Patellar Instability ◽

Trochlear Dysplasia ◽

Roc Curves ◽

Patellar Height ◽

Sulcus Angle ◽

Demographic Risk ◽

Demographic Risk Factors

Objectives: Multiple studies have described several anatomic and demographic risk factors of patellar instability (PI). Trochlear dysplasia (TD) has been shown to be a dominant risk factor for patellar instability but most prediction models have used the qualitative Dejour system to evaluate the influence of TD on PI. The lateral trochlear inclincation (LTI) angle is a described quantitative method to evaluate TD and a recent measurement technique has near perfect inter and intra rater reliability. Our hypothesis is that, in combination with other known radiographic and demographic risk factors of PI, that using a quantitative and numeric evaluation for TD, a highly reliable prediction model for PI can be created. Methods: 98 patients in a pediatric and adolescent sports medicine practice were identified with documented PI that had magnetic resonance imaging (MRI) studies available for review. A matched cohort of 100 patients with no history of PI but with MRI’s were identified as a control group. Anatomic risk factors evaluated included the LTI, sulcus angle, lateral condyle index (LCI), lateral patellar inclination angle (LPI), proximal and distal tibial tubercle-trochlear groove distance (pTTTG and dTTTG), Caton-Deschamps ratio (CD ratio), and patellotrochlear index (PTI). Demographic data included age and sex. Receiver operator characteristic (ROC) curves were constructed for each variable to identify which variables were the best predictors of PI (ROC value >0.7). Using the ROC curves with a Youden’s J statistic and setting specificity at 0.9, cutoff values for each variable were created. Each radiographic and demographic variable was analyzed for significance and those that were found to be significant were analyzed. Area under the curve (AUC) was determined for each variable. Two predictive models were created. One was developed from the ROC curve results while the other evaluated all measured variables. The models were designed to produce the best possible fit while trying to limit the total number of predictors. These models were tested on a second cohort of 45 patients with PI and 42 control patients. Results: ROC curve data is in Table 1. Of the two models, the superior model was the model that evaluated all variables, regardless of ROC cutoff value. The model takes on the form of a general logistic regression (Eq 1, Eq 2). Model accuracy on the validation set showed 84% accuracy with 78% sensitivity and 88% specificity. These values are based on a probability of >90%. Patellar height measures had significant AUC’s but were not prime drivers of the final model. Age was not significant in the ROC analysis. Conclusion: This study establishes a highly reliable and predictive model for PI that is driven by various direct (LTI, sulcus angle, LCI) or indirect (dTT-TG, LPI) quantitative measurements of TD. Patellar height did correlate with PI but was not a prime driver of the model which suggests that patella alta is a less common risk factor for PI.

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Classification of dysplasia of the femoral trochlea in patients with patellar instability depends on the evaluation plane

Journal of ISAKOS Joint Disorders & Orthopaedic Sports Medicine ◽

10.1136/jisakos-2019-000291 ◽

2019 ◽

Vol 4 (6) ◽

pp. 290-295

Author(s):

Yuzo Yamada ◽

Yukiyoshi Toritsuka ◽

Shuji Horibe ◽

Norimasa Nakamura ◽

Kazuomi Sugamoto ◽

...

Keyword(s):

Patellar Instability ◽

Articular Surface ◽

Trochlear Dysplasia ◽

Three Dimensional ◽

Reference Plane ◽

Transepicondylar Axis ◽

Predisposing Factor ◽

Femoral Trochlea ◽

Dejour Classification ◽

Axial View

ObjectiveTrochlear dysplasia is a major predisposing factor of patellar instability (PI). Dysplasia types are generally evaluated using the Dejour classification, but it is unclear whether this classification covers the entire spectrum. The objective of this study was to confirm whether the trochlear types on an axial view categorised according to the classification represent the entire trochlear shape.MethodsNinety knees from 81 patients with PI and 15 knees from 10 healthy volunteers (HVs) were evaluated. Three-dimensional knee models were created by MRIs. The femoral trochlear planes (FTPs) were defined as virtual cross sections including the transepicondylar axis, closer to the perpendicular plane of the articular surface. FTP 0 was defined as the reference plane including the proximal edge of the femoral trochlea and FTP θ as the plane making optional angle θ to FTP 0. Trochlear dysplasia types according to the classification were evaluated at every 10 degrees of FTPs up to 60 degrees (FTP 10, 20, 30, 40, 50 and 60). A trochlea with a sulcus angle <145° was defined as normal. Changes in the trochlear type according to FTPs, and agreement with clinical classification were evaluated.ResultsEighty-six knees (96%) in patients with PI and 12 (80%) in HVs showed changing trochlear types in different FTPs. Patterns of change varied among patients with PI and HVs. This suggests morphological variation of dysplastic trochleae. Agreement of trochlear type on each FTP with the clinically used Dejour classification was 42% on FTP 10, 49% on FTP 20, 33% on FTP 30, 22% on FTP 40, 22% on FTP 50% and 22% on FTP 60 in patients with PI, and 20% at FTP 10, 80% at FTP 20 and 100% on FTP 30 through FTP 60 in HVs. This suggests that the trochlear types in the clinically used plane do not always match the ones on the planes describing the contact surface to the patella.ConclusionThe trochlear types on an axial view provided by the Dejour classification do not represent the entire trochlear geometry. Multiple axial planes should be clinically used to more precisely describe the entire trochlear shape.

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