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 Table of Contents  
ORIGINAL ARTICLE
Year : 2022  |  Volume : 7  |  Issue : 2  |  Page : 232-240

Role of magnetic resonance imaging in assessment of extensor compartment abnormalities of knee joint – A cross-sectional study


1 Department of Radiodiagnosis, JNMC, KAHER University, Belagavi, India
2 Department of Orthopeadics, SDM University, Dharawd, India
3 Department of Radiodiagnosis, Gadag Institute of Medical Sciences, Gadag, Karnataka, India

Date of Submission30-May-2021
Date of Acceptance30-Aug-2022
Date of Web Publication06-Dec-2022

Correspondence Address:
Pradeep Siddappa Goudar
Department of Radiodiagnosis, JNMC, KAHER University, Belagavi, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/bjhs.bjhs_52_21

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  Abstract 


INTRODUCTION: The patellofemoral joint (PFJ) is a complex joint structure with high functional and biomechanical requirements. The magnetic resonance imaging (MRI) is an effective tool for definition and characterization of knee pathology as it can accurately detect, localize, and characterize various pathologies of the knee joint.
OBJECTIVES: (1) Evaluate MR images to identify different pathologies that are seen in the extensor compartment of the knee joint. (2) Quantitative assessment of patellofemoral measurements to determine predisposing risk factors that contribute to patellofemoral joint instability.
METHODOLOGY: A cross-sectional study was conducted from January 2017 to December 2017 with a sample size of 30 in the Department of Radiodiagnosis at The KLE's Dr. Prabhakar Kore Hospital and MRC, Belagavi. The data were collected using a pretested semi-structured questionnaire. The pro forma included sociodemographic profile of the study subjects, clinical presentation MRI to identify different pathologies that are seen in extensor compartment of the knee joint and quantitative assessment of patellofemoral measurements to determine predisposing risk factors that contribute to patellofemoral joint instability.
RESULTS: Among the study population majority of people had normal synovium, laterally subluxated/dislocated patella. Among the study population, the majority had normal lateral trochlear inclination angle, normal trochlear facet asymmetry, normal trochlear depth, normal sulcus angle, and trochlear dysplasia. Twenty-four (80%) people had normal Insall–Salvati index, 27 (90%) people had normal lateral patella femoral angle, 25 (83.30%) people had normal lateralization of the patella, 28 (93.30%) people had normal tibial tubercle to trochlear groove distance, majority, i.e., 11 (36.70%) had Hoffa's fat pad edema followed by chondromalacia patella, trochlear dysplasia, medial patellofemoral ligament tear, patella alta, synovial plicae, subluxated/dislocated patella, transient dislocated patella, Osgood–Schlatter disease, and patellar tendonitis.
CONCLUSION: MRI has also been useful in identifying extensor compartment pathologies that lead to anterior knee pain.

Keywords: Extensor compartment of knee, magnetic resonance imaging, patellofemoral joint


How to cite this article:
Patil SD, Raman V, Goudar PS, Patil AD, Patil P. Role of magnetic resonance imaging in assessment of extensor compartment abnormalities of knee joint – A cross-sectional study. BLDE Univ J Health Sci 2022;7:232-40

How to cite this URL:
Patil SD, Raman V, Goudar PS, Patil AD, Patil P. Role of magnetic resonance imaging in assessment of extensor compartment abnormalities of knee joint – A cross-sectional study. BLDE Univ J Health Sci [serial online] 2022 [cited 2023 Jan 28];7:232-40. Available from: https://www.bldeujournalhs.in/text.asp?2022/7/2/232/362836



The knee joint is the largest joint of the human body. It is a modified hinge joint made up of two individual components – tibiofemoral and patellofemoral joints (PFJs).[1],[2] Knee pain is one of the most common problems faced by people.[3],[4] Anterior knee pain is a common complaint in physically active individuals. The reason for this is multifactorial with patellar abnormalities or extensor mechanism disorders being the cause for patellar malalignment during joint movement.

The PFJ is a complex joint structure with high functional and biomechanical requirements.[5] The normal functioning of this joint (extension of the knee) is dependent on the congruent relationship of the patella with the trochlear groove. Pathologic conditions involving the extensor compartment of the knee are challenging in clinical practice and can result in significant morbidity if not treated in time. Traumatic injuries, inflammatory processes, congenital abnormalities, and rarely neoplastic conditions may be seen in this area.

Acute or chronic osteochondritis may affect the patella in a disease such as Sinding-Larsen-Johansson or the tibial tuberosity in Osgood–Schlatter. Although radiography may be used in the initial evaluation of these conditions, magnetic resonance imaging (MRI) is an important tool for a precise diagnosis.[6],[7] Patellofemoral pain syndrome is the leading cause of knee pain in patients younger than 45 years.[3]

It may be related to an underlying patellar tracking abnormality or patellofemoral impingement. The role of MRI has steadily increased and has been shown to be an effective tool for definition and characterization of knee pathology as it can accurately detect, localize, and characterize various pathologies of the knee joint and help in arriving at a correct anatomical diagnosis thereby grading further management of the patient.[8],[9],[10],[11]

The need of the study arises because the literature in India with respect to MRI imaging of extensor compartment injuries and correlating it with the associated factors are very limited and still, several doubts persist regarding the anatomical variations and function of some structures in the joint dynamics of the knee extensor mechanism[12],[13],[14] and the factors contributing to it. Hence, this study was undertaken to study the different extensor compartment pathologies and identify the risk factors along with different patellofemoral measurements that contribute to it.

Objectives

  1. Evaluate MRI to identify different pathologies that are seen in the extensor compartment of the knee joint
  2. Quantitative assessment of patellofemoral measurements to determine predisposing risk factors that contribute to patellofemoral joint instability.



  Methodology Top


Study site

This study was conducted in the Department of Radiodiagnosis at KLE's Dr. Prabhakar Kore Hospital and MRC, Belagavi.

Study population

Patients who were referred to the Department of Radiodiagnosis at The KLE's Dr. Prabhakar Kore Hospital and MRC, Belagavi, with suspicion of or clinically diagnosed with extensor compartment abnormality of the knee joint were considered as the study population.

Study design

The current study was a cross-sectional study.

Sample size

The prevalence of extensor compartment abnormalities of the knee joint in the Indian population in most of the studies done is very less. Therefore, all cases fitting into the inclusion criteria during the study period were included in the study. The study had included a total of 30 subjects in the final analysis.

Sampling method

All eligible subjects were recruited into the study consecutively by convenient sampling till the sample size was reached.

Study duration

The data collection for the study was done between January 2017 and December 2017 over a period of 1 year.

Inclusion criteria

All patients, of different age groups presenting primarily with anterior knee joint pain not responding to conservative treatment, were sent for MRI of the knee.

Exclusion criteria

  1. Patients with proven knee arthropathies, infective, and inflammatory etiology
  2. Traumatic cases
  3. Postoperative cases
  4. Patients with ferromagnetic implants, pacemakers, and aneurysm clips.


Ethical considerations

Study was approved by the institutional human ethics committee. Informed written consent was obtained from all the study participants, and only those participants willing to sign the informed consent were included in the study. The risks and benefits involved in the study and voluntary nature of participation were explained to the participants before obtaining consent. The confidentiality of the study participants was maintained.

Data collection tools

All the relevant parameters were documented in a structured study pro forma.

Method of data collection

MRI knee of all the patients was done using 1.5 Tesla Symphony Maestro class-MRI with help of a dedicated knee coil.

Scan protocol

MRI T2 PD Coronal/sagittal; T2 Axial; T2 IRM Coronal; T1 SE Coronal/Sagittal; STIR Coronal; STIR Axial; MEDIC FAT SAT Sagittal PD FAT coronal/sagittal/transverse.

The following parameters were assessed: patellar height ratio, lateral trochlear inclination angle, sulcus angle, trochlear facet asymmetry, trochlear depth, lateral patellofemoral angle, lateralization of patella, and tibial tubercle (TT) to trochlear groove (TG) distance [Table 1].
Table 1: Technique with cut off values of magnetic resonance imaging parameters for determining patellofemoral instability in my study

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Statistical methods

Descriptive analysis was carried out by the mean and standard deviation for quantitative variables, frequency, and proportion for categorical variables.

IBM SPSS version 22 (IBM Corp. IBM SPSS Statistics for Windows. Ver. 22.0. Armonk, 48 NY: IBM Corp; 2013) was used for statistical analysis.[15]


  Results Top


A total of 30 subjects were included in the final analysis. The mean age was 34.87 years ± 15.96. The minimum age was 11 years, and the maximum age was 70 years in the study population. Among the study population, 18 (60%) people were male and remaining 12 (40%) people were female [Table 2].
Table 2: Demographic profile of the study population (n=30)

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Among the study population, 17 (56.70%) people had right-side involvement and 13 (42.30%) people had left-side involvement. The mean duration of pain was 4.8 ± 5.09 months. Minimum duration was 1 month, and maximum duration was 24 months in the study population. Among the study population, 22 (73.30%) people had pain in anterior location, 5 (16.70%) people had in anterior and medial location, and remaining 3 (10%) people had diffuse pain. Majority of the population, 15 (50%) people had pain and tenderness, 13 (43.30%) people had stiffness, 12 (40%) people had a similar history in the past and 11 (36.70%) people had the restriction on movements [Table 3].
Table 3: Clinical presentation of the study population (n=30)

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Among the study population, 2 (6.70%) people had patellar tendonitis and 2 (6.70%) people had heterotopic ossification of patellar tendon at tibial insertion/Osgood–Schlatter disease. Among the study population, 5 (16.70%) people had complete medial patellofemoral ligament (MPFL) tear, 1 (3.30%) person had a partial tear, and 1 (3.30%) person had reconstructed MPFL. Majority of the population, 5 (16.70%) people had osteochondral defect at lateral patella and 4 (13.30%) people had an osteochondral defect at medial patella. Among the study population, 14 (46.70%) people had edema in Hoffa's fat pad.

Among the study population, 2 (6.70%) people had marrow edema/contusion present subchondral lateral patella, 2 (6.70%) people had it present on the subchondral medial patella, 2 (6.70%) people had it present on lateral tibial and femoral condyle and 3 (10%) people had kissing contusions. Among the study population, 22 (73.30%) people had normal synovium, 2 (6.70%) people had synovial hypertrophy and 6 (20%) people had synovial plicae. Among the study population, 4 (13.30%) people had laterally subluxated/dislocated patella, and 3 (10%) people had prior/transient subluxated patella. The mean of joint effusion was 0.82 ± 0.61. The minimum level was 0 and maximum level was 2 in the study population (95% confidence interval [CI] 0.58–1.06). Among the study population, 9 (30%) people had mild joint effusion, 8 (26.70%) people had moderate joint effusion and 2 (6.70%) people had severe joint effusion [Table 4].
Table 4: Clinical and magnetic resonance imaging findings of the study population (n=30)

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The mean of lateral trochlear inclination angle was 20.1 ± 5.03. The minimum level was 10 and maximum level was 32 in the study population (95% CI 18.22–21.98). The mean of trochlear facet asymmetry was 68.5 ± 12.02. The minimum level was 50 and maximum level was 90 in the study population (95% CI 64.01–72.99). The mean of trochlear depth was 4.77 ± 1.58. The minimum level was 2 and maximum level was 7 in the study population (95% CI 4.18–5.36). The mean of sulcus angle was 142.07 ± 8.96. The minimum level was 127 and maximum level was 162 in the study population (95% CI 138.72–145.41). The mean of Insall–Salvati index was 1.14 ± 0.17. The minimum level was 0.90 and the maximum level was 1.44 in the study population (95% CI 1.07–1.20). The mean of TT to TG distance was 10.36 ± 3.6. The minimum level was 1 and the maximum level was 19 in the study population (95% CI 9.00–11.53) [Table 5].
Table 5: Trochlear measurements, Insall-Salvati index, and tibial tubercle to trochlear groove distance in the study population (n=30)

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Among the study population, 27 (90%) people had normal lateral trochlear inclination angle and remaining 3 (10%) people had abnormal or decreased lateral trochlear inclination angle. Among the study population, all 30 (100%) people had normal trochlear facet asymmetry. Among the study population, 21 (70%) people had normal trochlear depth and 9 (30%) people had decreased trochlear depth. Among the study population, 21 (70%) people had a normal sulcus angle and 9 (30%) people had increased sulcus angle. Trochlear dysplasia was confirmed in 9 (30%) people out of the 30 in the study population [Table 6]. Among the study population, 24 (80%) people had normal Insall–Salvati index and 6 (20%) people had increased index (i.e., they were diagnosed to have patella alta) [Table 7].
Table 6: Trochlear measurements in the study population (n=30)

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Table 7: Insall-Salvati index in the study population (n=30)

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Among the study population, 27 (90%) people had normal lateral patella femoral angle and 3 (10%) people had abnormal lateral patella femoral angle (i.e., they were diagnosed to have patellar tilt) [Table 8].
Table 8: Lateral patellofemoral angle in the study population (n=30)

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Among the study population, 25 (83.30%) people had normal lateralization of the patella and 5 (16.70%) people had abnormal lateralization of the patella [Table 9].
Table 9: Lateralization of the patella in the study population (n=30)

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Among the study population, 28 (93.30%) people had normal TT to TG distance and 2 (6.70%) people had increased/abnormal TT to TG distance [Table 10].
Table 10: Tibialtubercle to trochlear groove distance in the study population (n=30)

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Majority of the population 15 (57.70%) people had no other associated findings, 3 (11.50%) people had a medial meniscal tear (posterior horn), and 2 (7.70%) people had varicose veins [Table 11].
Table 11: Descriptive analysis of other findings in the study population (n=30)

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Among the study population majority of people, 11 (36.70%) had Hoffa's fat pad edema, 9 (30%) people had chondromalacia patella, 9 (30%) people had trochlear dysplasia, 6 (20%) people had MPFL tear, 6 (20% people) had patella alta, 6 (20%) people had synovial plicae, 7 (23.30%) people were diagnosed with subluxated/dislocated patella, 3 (10%) people had transient dislocated patella, 2 (6.70%) people were diagnosed with Osgood–Schlatter disease, 2 (6.70%) people had patellar tendonitis, 3 (10%) people had no abnormal findings, and 1 (3.30%) person presented with the asymmetrical patella [Table 12].
Table 12: Final diagnosis in the study population (n=30)

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  Discussion Top


Baseline demographic characteristics and clinical features

Our study population included 30 subjects out of which 60% were male and 40% were female and the mean age was 34.87 years. 56.7% had right-sided knee pain while 42.3% had left-side involvement. Osman and Ebrahim[16] enrolled knee MRI scans of 38 patients with lateral patellar dislocation in their study with a mean age of 32 years, similar to subjects in our study who had a mean age of 35 years. Similar to our study, most of the previous studies had enrolled more males than females in their study. Majority of the study population (50%) people had Pain and Tenderness while 43.3% also reported joint stiffness and 36.7% had restriction of movements. In our study, subjects suffered from knee pain for a mean duration of 4.8 months. 73.3% of subjects had pain in the anterior location and 16.7% had pain in the anterior and medial location, while 10% had diffuse pain.

Patellar dislocation and correlation with medial patellofemoral ligament tear

In our study, 23.3% had subluxated or dislocated patella as confirmed by MRI. 13.3% had laterally subluxated/dislocated patella and 10% had signs of prior/transient patellar subluxation. Fahmy et al.[17] observed disruption of the MPFL in 31% of subjects while in our study 20% had MPFL tear. In our study, 16.7% had complete MPFL tear, 3.3% had a partial tear of MPFL, and 3.3% had reconstructed MPFL. 76.7% had no MPFL injury. Balcarek et al.[18] in their study observed that injury to the MPFL was found in 98.6% of the patients after the acute lymphoproliferative disorder, with a complete tear in 51.4%, most commonly seen at the femoral attachment site, and a partial tear in 48.6%. Their study showed that patterns of MPFL injury depend on trochlear dysplasia, patellar height, and TT-TG distance. In our study, the correlation between MPFL injury and patellar dislocation was strong. MPFL injury was absent in 76.7% of subjects and patellar dislocation was also absent in 76.7% of the subjects. Out of the remaining 23.3% with MPFL injury, there was prior/transient subluxation in 10% of subjects and acute lateral subluxation in 13.3% of subjects. In our study population, 90% had the normal lateral trochlear inclination angle and the remaining 10% had abnormal or decreased lateral trochlear inclination.

Patellar tendon and fat pad injuries

In our study population, 6.7% of subjects had Patellar Tendonitis and those with heterotopic ossification of the patellar tendon at tibial insertion/Osgood–Schlatter disease was 6.7%. In our study, 36.7% had Hoffa's fat pad edema or impingement, and similarly, Fahmy et al.[17] observed that in the 55 knees they analyzed for patellofemoral instability, there was Hoffa's fat pad edema in 55% of their study subjects. Immunohistochemical studies have shown that in comparison to a normal individual, patients with anterior knee pain have more nerve fibers in their anterior fat pads.[19] It has also been implied that suprapatellar pouch impingement, which manifests as quadriceps fat pad edema or enlargement, also contributes to pain in some patients.[20]

Trochlear dysplasia and patellar malalignment

Trochlear dysplasia was observed in 9 (30.0%) subjects. Of the 9 (30.0%) subjects who presented with dysplasia, all 9 had shallow trochlear depth and increased sulcus angle and 3 subjects had abnormal or decreased lateral trochlear inclination. Fahmy et al.[17] observed trochlear dysplasia in a very higher proportion of subjects at about 63%. Similarly, Kurtul Yildiz et al.[9] observed that in their study, the frequencies of patellar malalignment and trochlear dysplasia were 34.7 and 63.7%, respectively. Souza et al.[21] also reported that trochlear dysplasia was present in 51% of the cases who presented with patellar instability and were easily identified using MRI. In our study, subluxated or dislocated patella was found in 23.3% of subjects out of which 13.3% had an acute history of laterally subluxated/dislocated patella and 10% had prior/transient subluxated patella.

In our study, high riding patella/patella alta was found in 20% of subjects. Fahmy et al.[17] observed that in the 55 knees they analyzed for patellofemoral instability, high patella was found in 56% of subjects, a laterally inclined patella in 31% of subjects, cartilaginous injuries were found in 58%, joint morphology abnormalities in 74.5% of patients, and bone edema in 27% of patients.

In our study, 30% of subjects were diagnosed with chondromalacia patella out of which 16.7% had an osteochondral defect at the lateral patella and 13.3% had an osteochondral defect at the medial patella. Chondromalacia patellae were detected in 44 knees and were absent in 54 knees at arthroscopy in a study done by Endo et al.[22]

Bone contusion and kissing contusion

Seventy percent of our subjects had no visible edema or contusion on MRI. In our study, single contusion/marrow edema was present in 20.0% of the subjects out of which 6.7% had it on the subchondral medial patella, 6.7% had it on the subchondral lateral patella and 6.7% had it on either lateral tibial or femoral condyles.

In our study, kissing contusion was seen in 10% of subjects that signified prior subluxation/dislocation. Terzidis et al.[23] reported that in their study bone contusions were diagnosed in 27.8% of subjects that is almost similar to our study (30%). In their study, 22.5% had single contusions and 6.3% had kissing contusions. In our study, kissing contusions was reported in a slightly higher proportion (10%) of subjects.

Joint effusion, synovial plicae, hypertrophy, and other findings

In our study, 6.7% had synovial hypertrophy while 20% had synovial plicae. In our study, 63.3% of the subjects had joint effusion out of which 30% had mild joint effusion, 26.7% had moderate joint effusion, and 6.7% had severe joint effusion. Osman and Ebrahim[16] in their study on subjects with patellofemoral instability observed that a total of 60.5% of the study group had joint effusion similar to our study. In our study, the majority of the population (57.7%) had no other associated findings with 11.5% having medial meniscal tear (Posterior horn).

In our study, there was wide variability in the comparison of our results to relevant studies. This could be due to variabilities in the sample sizes when dealing with prevalences/percentages. The other attributable factor while comparing the numerical values of the measured MR parameters could be racial/population differences.

Indices of measurements at trochlea and patella

In our study, all subjects had normal trochlear facet asymmetry. 70% of the subjects had normal trochlear depth and 30% presented with decreased trochlear depth. Osman and Ebrahim[16] observed abnormal trochlear depth in 57.9% of subjects. The sulcus angle was normal in 70% of subjects and was increased in 30% of the subjects in our study. Osman and Ebrahim[16] observed normal sulcus angle in 42.1% of subjects while 57.9% had abnormal sulcus angle.

The patellar height ratio known as the Insall–Salvati index is a measure for patella alta. In our study, 80% had normal Insall-Salvati index and 20% had increased index (Patella Alta) while Osman and Ebrahim[16] observed abnormal Insall–Salvati index in 52.6% of subjects.

Grelsamer et al.[24] in their study reported that the mean tilt angle in a group of patients suspected to have patellofemoral malalignment was 12° ± 6°. In our study, 10% of subjects in our study had abnormal patellofemoral angle/patellar tilt. Abnormal lateralization of a patella of more than 6 mm was observed in 16.7% of subjects in our study. Osman and Ebrahim[16] observed a greater proportion of subjects with abnormal patellar tilt compared to our study. In their study, 26.3% of subjects had abnormal patellar tilt. Similarly, Steensen et al.[25] also reported abnormal patellar tilt in 26.7% of their study subjects.

In our study, the TT to TG distance was increased or abnormal only in 6.7% of subjects compared to 13.1% in a study by Osman and Ebrahim[16] and 42% in a study done by Steensen et al.[25]

Insall–Salvati index had the highest positive predictive value of 90.9% with 52.6% sensitivity and 94.7% specificity in the study by Osman and Ebrahim[16] In our study, the mean Insall–Salvati index was1.14 ± 0.17 while Osman and Ebrahim[16] observed a slightly higher index of 1.34 ± 0.09 in their study. Ali et al.[26] in their study on subjects, <40 years old observed Insall–Salvati index of 1.08 ± 0.17 in subjects with no cartilage defect while it was 1.3 ± 0.3 in subjects with mild cartilage defects and 1.17 ± 0.11 in subjects with severe cartilage defects. They also observed an association between abnormal trochlear morphology and patellofemoral cartilage defects in patients younger than 40 years.

In our study, the mean trochlear depth was 4.77 ± 1.58, and the mean sulcus angle was142.07 ± 8.96 degrees while Osman and Ebrahim[16] observed a lower trochlear depth of 2.4 ± 0.4 in their study and a higher sulcus angle of 152.7 ± 7.4 in their study. In our study, the mean TT to TG distance was 10.36 ± 3.6 mm while Osman and Ebrahim[16] observed a very higher TT to TG distance of 27.3 ± 5.1 mm in their study. In our study, the mean lateral trochlear inclination angle was 20.1 ± 5.03 degrees while it was only 6.9° ± 2.6° in the study bone by Osman and Ebrahim.[16]

In conclusion, MRI knee confirmed extensor compartment abnormalities in 90% of the subjects in our study. Trochlear dysplasia was seen in 30% of the subjects, patella alta in 20%, patellar tilt in 10%, and increased TT-TG distance in 6.7%. MR imaging has emerged as the first modality of choice in young patients who present with anterior knee pain or in whom patellofemoral instability is clinically suspected. MR imaging not only helps in diagnosing different anatomic variants, ligamentous injuries, and chondral lesions that lead to instability but also guide surgeons in selecting the most optimal treatment.


  Conclusion Top


In our study, 23.3% of the subjects had acute or prior/transient subluxated patella. 16.7% of them showed complete MPFL tear, 3.3% showed a partial tear, and 3.3% had reconstructed MPFL. Of the PFJ abnormalities, 30% of the subjects had trochlear dysplasia, 20% had patella alta, 10% had patellar tilt, and 6.7% had increased TT-TG distance. Of the 9 (30%) subjects who were diagnosed with trochlear dysplasia, all 9 (30%) had shallow/decreased trochlear depth and increased sulcus angle and 3 (10%) subjects had abnormal or decreased lateral trochlear inclination angle. All subjects had normal trochlear facet asymmetry. The mean Insall–Salvati index was 1.14 ± 0.17. The mean trochlear depth was 4.77 ± 1.58, the mean sulcus angle was 142.07° ± 8.96° and the mean lateral trochlear inclination angle was 20.1 ± 5.03. The mean TT to TG distance was 10.36 ± 3.6 mm. 6.7% of the subjects had patellar tendonitis and Osgood–Schlatter disease/heterotopic ossification of the patellar tendon at tibial insertion was seen in 6.7%. 30% of subjects had chondromalacia patella. 16.7% had osteochondral defect at the lateral patella and 13.3% had osteochondral defect at the medial patella. 20% of the subjects had Synovial plicae. 30% had mild joint effusion, while 26.7% had moderate joint effusion and 6.7% had severe joint effusion. 36.7% of subjects had edema involving Hoffa's fat pad. Our study has important diagnostic implications as quantitative measurements on MRI provide valuable information regarding the predisposing factors that contribute to PFJ instability. MRI has also been useful in identifying extensor compartment pathologies that lead to anterior knee pain.

Limitations

In our study, only symptomatic knee patients were analyzed and the study sample size was smaller. One limiting factor of MRI imaging is the extended knee that causes physiological lateralization and inclination of the patella. Hence, the evaluation of these parameters should be done in flexed knee position, which is not routinely done during MR imaging of the knee joint.

Recommendations

The capacity to combinedly evaluate bone, cartilage and soft-tissue structures has made MRI the preferred imaging modality in assessing patellofemoral joint pathologies. A broader spectrum prospective study is the need of the hour in the assessment of the predisposing factors of patellofemoral derangements.

Acknowledgment

The authors would like to thank the Professor and Head Department of Radiodiagnosis and Department of Radiodiagnosis, JNMC, Belagavi for their kind support. The authors are also grateful to authors/editors/publishers of all those articles, journals and books from where the literature for this article has been reviewed and discussed. The authors also thank all the study subjects for their kind support.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12]



 

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