MAGNETIC RESONANCE IMAGING OF THE KNEE IN CHILDREN AND ADOLESCENTS: ITS ROLE IN CLINICAL DECISION-MAKING

Social deprivation index affects time to MRI after knee injury in pediatric patients and is predicted by patient demographics

OBJECTIVES

This study aims to characterize the association between the timing of MRI ordering and completion for pediatric knee injuries and Social Deprivation Index (SDI), which is a comprehensive, validated, county-level, measure of socioeconomic variation in health outcomes based upon combining geography, income, education, employment, housing, household characteristics, and access to transportation.

METHODS

A retrospective chart review was completed of patients 21 years old and younger from our institution with a history of knee sports injury (ligamentous/soft tissue injury, structural abnormality, instability, inflammation) evaluated with MRI between 5/26/2017 and 12/28/2020. Patients were from three states and attended to by physicians associated with an urban academic institution. Patients were assigned SDI scores based on their ZIP code. Excluded from the study were patients with a non-knee related diagnosis (hip, foot, or ankle), patients from ZIP codes with unknown SDI, and non-sports medicine diagnoses (tumor, infection, fracture).

RESULTS

In a multivariate regression analysis of 355 patients, increased SDI was independently associated with increased time from clinic visit to MRI order (p = 0.044) and from clinic visit to MRI completion (p = 0.047). Each 10-point increase in SDI (0-100) was associated with a delay of 7.2 days on average. SDI itself was found to be associated with a patient's race (p < 0.001), ethnicity (p < 0.001), and insurance category (p < 0.001).

CONCLUSION

Increased SDI is independently associated with longer time from clinic visit to knee MRI order and longer time from clinic visit to knee MRI completion in our pediatric population. Recognizing potential barriers to orthopedic care can help create the change necessary to provide the best possible care for all individual patients.

Physician preferences in diagnostics and treatment of juvenile osteochondritis dissecans are diverse across the knee, ankle and elbow: an ESSKA survey

PURPOSE

To investigate the current preferences regarding the work-up and treatment choices of juvenile osteochondritis dissecans (JOCD) of the knee, ankle and elbow among orthopaedic surgeons.

METHODS

An international survey was set up for all European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) members, which assessed various questions on diagnosis and treatment of JOCD of different joints. Respondents answered questions for one or more joints, based on their expertise. Proportions of answers were calculated and compared between joints. Consensus was defined as more than 75% agreement on an item; disagreement was defined as less than 25% agreement.

RESULTS

Fifty physicians responded to the survey, of whom forty-two filled out the questions on the knee, fourteen on the ankle and nine on the elbow. Plain radiography and MRI were the most used imaging modalities for the assessment and follow-up of JOCD in the knee and ankle, but not for the elbow. MRI was also the preferred method to assess the stability of a lesion in the knee and ankle. There was universal agreement on activity and/or sports restriction as the non-operative treatment of choice for JOCD. Size, stability and physeal closure were the most important prognostic factors in determining the operative technique for the elbow. For the knee, these factors were size and stability and for the ankle, these were size and location.

CONCLUSION

Activity and/or sports restriction was the non-operative treatment of choice. Furthermore, plain radiography and MRI were the preferred imaging modalities for the knee and ankle, but not for the elbow. For determining the operative technique, physicians agreed that the size of the lesion is an important prognostic factor in all joints. These findings help us understand how juvenile osteochondritis dissecans is treated in current practice and may provide opportunities for improvement.

LEVEL OF EVIDENCE

Level V.

Classification Systems for Knee Osteochondritis Dissecans: A Systematic Review

OBJECTIVE

Aim of this systematic review was to describe all classification systems for knee osteochondritis dissecans (OCD) lesions, evaluating their accuracy and reliability, as well as their use in the literature on knee OCD.

DESIGN

A systematic review of the literature was performed in July 2021 on PubMed, WebOfScience, and Cochrane Collaboration (library) to describe all published classification systems for knee OCD lesions and quantify the use of these classifications in the literature.

RESULTS

Out of 1,664 records, 30 studies on 33 OCD classifications systems were identified, describing 11 radiographic, 13 MRI, and 9 arthroscopic classifications. The search included 193 clinical studies applying at least one OCD classification, for a total of 7,299 knee OCD cases. Radiographic classifications were applied to 35.8%, MRI to 35.2%, and arthroscopic classifications to 64.2% of the included studies. Among these, in the last two decades, the International Cartilage Repair Society's (ICRS) arthroscopic classification was the most described approach in studies on knee OCD. Overall, there is a lack of data on accuracy and reliability of the available systems.

CONCLUSIONS

Several classifications are available, with ICRS being the most used system over the time period studied. Arthroscopy allows to confirm lesion stability, but noninvasive imaging approaches are the first line to guide patient management. Among these, radiographic classifications are still widely used, despite being partially superseded by MRI, because of its capability to detect the earliest disease stages and to distinguish stable from unstable lesions, and thus to define the most suitable conservative or surgical approach to manage patients affected by knee OCD.

LEVEL OF EVIDENCE

Systematic review, level IV.

Sensitivity and Specificity of MRI in Diagnosing Concomitant Meniscal Injuries With Pediatric and Adolescent Acute ACL Tears

Background:

Preoperative diagnosis of concomitant meniscal tears in pediatric and adolescent patients with acute anterior cruciate ligament (ACL) deficiency is challenging.

Purpose:

To investigate the diagnostic performance of magnetic resonance imaging (MRI) in detecting meniscal injuries for pediatric and adolescent patients with acute ACL tears.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

The authors retrospectively identified patients aged ≤18 years who underwent acute ACL reconstruction between 2006 and 2018 at 2 tertiary academic hospitals. The primary outcomes were arthroscopically confirmed medial, lateral, or any (defined as medial and/or lateral) meniscal tears. To control for chronically deficient knees, patients must have received their MRI study within 4 weeks of injury and must have undergone surgery no more than 8 weeks after their MRI study. Preoperative MRI reports were compared with the gold standard of arthroscopically confirmed tears to calculate sensitivity, specificity, positive predictive value, and negative predictive value. In a secondary analysis, patients were stratified by age into 2 groups (≤13 or ≥14 years), body mass index-for-age data from the Centers for Disease Control were used to classify patients as obese or nonobese, and differences between sensitivity and specificity proportions were analyzed using chi-square test for homogeneity.

Results:

Overall, 406 patients with a mean age of 15.4 years (range, 10-18 years) were identified. The sensitivity, specificity, positive predictive value, and negative predictive value were as follows: for lateral meniscal (LM) tears, 51.0%, 86.5%, 78.3%, and 65.0%; for medial meniscal tears, 83.2%, 80.6%, 62.3%, and 92.5%; and for any meniscal tear, 75.0%, 72.1%, 81.5%, and 63.8%, respectively. In the stratified analysis, MRI was less specific for the following diagnoses: any meniscal tear in patients aged ≤13 years (P = .048) and LM tears in obese patients (P = .020).

Conclusion:

The diagnostic ability of MRI to predict meniscal injuries present at acute ACL reconstruction was moderate. Performance was poorest at the lateral meniscus, where MRI failed to detect 97 tears that were found arthroscopically. Specificity was significantly lower in younger patients for any meniscal tear and in obese patients for LM tears.

Recurrent Patellar Instability: Implications of Preoperative Patellar Crepitation on the Status of the Patellofemoral Articular Cartilage

BACKGROUND

The purpose of the study was to quantify the frequency, severity, and location of patellofemoral (PF) articular cartilage changes recurrent patellar instability treated surgically in patients with preoperative clinical patellar crepitation.

METHODS

A single-surgeon database was queried for all knees with recurrent patellar instability between 3/2000 and 6/2012 (n=214). Only knees which underwent knee arthroscopy during the surgical treatment were included (n=148). PF articular cartilage condition was assessed arthroscopically.

RESULTS

There were 148 knees in 130 patients (mean age, 16 y), which met inclusion criteria. There were 93 females and 37 males. Diagnoses were dislocations [122 (82.4%)] and subluxations (26). Preoperatively 28 knees (18.9%) had PF crepitation. Statistical analysis demonstrated preoperative PF crepitation was correlated with medial patellar facet lesions (P=0.0022) and were 3.6 times more likely to have medial patellar facet lesions. Crepitation was correlated with the higher outerbridge (OB) patellar grades (P<0.0001) and larger patellar lesion size (P=0.0021). At arthroscopy 89 knees (60.5%) had patellar articular cartilage damage with a mean OB grade of 1.3 (0 to 4) and mean size of 93.2 mm (0 to 750). The femoral articular cartilage was identified in 29 knees (19.7%) with a mean OB grade of 0.44 (0 to 4).

CONCLUSIONS

PF articular damage was present in 63% of knees, which were surgically treated for patellar instability. The patella was involved in 61% (mean, 129 mm) and femoral trochlea in 20% (mean 166 mm) of knees. Knee with preoperative PF crepitation (20% of cohort) more commonly had medial patellar facet lesions with higher OB grades, and larger patellar lesion size than knees without preoperative crepitation. Because of the high frequency of patellar (83%) and femoral (36%) articular damage documented at the time of surgical reconstruction, visualization of the PF joint is recommended when knees have preoperative PF crepitation.

LEVEL OF EVIDENCE

Level IV.

Accuracy of 3-Tesla magnetic resonance imaging for the diagnosis of intra-articular knee injuries in children and teenagers

BACKGROUND

Magnetic resonance imaging (MRI) is a commonly used tool for the diagnosis of intra-articular knee pathologies. Although many studies have reported the accuracy of MRI in the adult population, fewer studies have investigated these tests in younger patients. Furthermore, these studies have shown a higher variability in both the sensitivity and the specificity of MRI for these knee injuries in this age group. Advancements in MRI technology, such as the 3-Tesla (3T) MRI magnet, have shown promising results for musculoskeletal injury diagnosis in adults. This study aims to evaluate 3 T MRI for the diagnosis of intra-articular knee pathologies in a pediatric and adolescent patient population.

METHODS

The records of 116 patients (119 knees) under the age of 20 years who underwent 3 T MRI studies of the knee and subsequent knee arthroscopy were reviewed retrospectively. The MRI report from the musculoskeletal radiology staff, the interpretation from the staff orthopedic surgeon, and the operative note dictations were compared, with a focus on meniscus and anterior cruciate ligament (ACL) pathologies. Seventeen orthopedic staff reads were not obtainable. Arthroscopy was used as the gold standard for diagnosis.

RESULTS

The average age at MRI exam was 16.0 years and at surgery was 16.2 years. Using the musculoskeletal radiologist interpretation, the sensitivity and the specificity of 3 T MRI were 81.0% and 90.9% for medial meniscus injuries, 68.8% and 93% for lateral meniscus injuries, and 97.9% and 98.6% for ACL injuries, respectively. The orthopedic surgeon's interpretation of 3 T MRI had a sensitivity and specificity of 75.7% and 92.4% for medial meniscus injuries, 69.8% and 98.3% for lateral meniscus injuries, and 100% and 98.6% for ACL injuries, respectively. Posterior horn tears had the greatest discrepancies.

CONCLUSIONS

When performed on pediatric and adolescent patients, newer 3 T MRI studies have excellent accuracy for diagnosing ACL tears. These studies also show a higher accuracy for the diagnosis of medial meniscal tears than lateral meniscal tears.

LEVEL OF EVIDENCE

Diagnostic study--Level 2.

The clinical utility and diagnostic performance of MRI for identification and classification of knee osteochondritis dissecans

BACKGROUND

Magnetic resonance imaging (MRI) is a common clinical tool used to diagnose and monitor the progression and/or healing of osteochondritis dissecans of the knee. The purpose of this study was to systematically review the literature relative to the following questions: (1) Is MRI a valid, sensitive, specific, accurate, and reliable imaging modality to identify knee osteochondritis dissecans compared with arthroscopy? (2) Is MRI a sensitive tool that can be utilized to characterize lesion severity and stability of osteochondritis dissecans fragments in the knee?

METHODS

A systematic search was performed in December 2010 with use of PubMed MEDLINE (from 1966), CINAHL (from 1982), SPORTDiscus (from 1985), Scopus (from 1996), and EMBASE (from 1974) databases.

RESULTS

Seven studies, four Level-II and three Level-III investigations, met the specified inclusion criteria. No randomized controlled studies were identified. Because of inconsistencies between imaging techniques and methodological shortcomings of many of the studies, a meta-analysis was not performed.

CONCLUSIONS

The limited available evidence, methodological inconsistencies in imaging techniques, and lack of standardized grading criteria used in current studies prevent clear conclusions regarding the diagnostic and specific staging equivalency of MRI with arthroscopy. However, available evidence supports the use of MRI to detect the stability or instability of the lesion. Given the benefits of the use of MRI as a noninvasive tool to diagnose, predict lesion progression, and assess clinical outcomes of treatment, there is a pressing need for high-level, systematic, sound, and thorough studies related to the clinical utility of MRI for assessing osteochondritis dissecans of the knee.

Symptomatic bilateral discoid menisci in children: a comparison with unilaterally symptomatic patients

BACKGROUND

In previous studies, 5% to 20% of patients with a discoid lateral meniscus eventually require surgery bilaterally for symptomatic discoid menisci. However, there are little published data specifically on children who require treatment for discoid menisci in both knees. The purpose of this study is to identify differences in clinical and arthroscopic findings between children who require bilateral versus unilateral treatment for symptomatic discoid lateral menisci.

METHODS

We retrospectively reviewed the records of all patients aged 18 years or younger requiring treatment of discoid lateral meniscus between 1998 and 2007. Data were collected on 16 patients (32 knees) with symptomatic bilateral discoid menisci and 60 patients treated unilaterally with an asymptomatic contralateral knee.

RESULTS

At initial presentation, children who were treated bilaterally for discoid menisci were younger than those treated unilaterally (10.4 vs. 12.5 y; P=0.021). Patients under 12 years of age were 4.6 times more likely to eventually require surgery on both knees (P=0.015). Watanabe classification was as follows: complete, 65% bilateral versus 30% unilateral; incomplete, 22% bilateral versus 68% unilateral; and Wrisberg, 13% bilateral versus 2% unilateral (P<0.001). The odds of current or future bilateral symptoms requiring treatment were 4.5 times higher in patients with a complete discoid meniscus (P=0.0017) and 8.4 times higher in those with a Wrisberg type (P=0.048). A tear of the lateral meniscus was more likely to be found intraoperatively in unilateral knees than bilateral (90% vs. 72%; P=0.037).

CONCLUSIONS

Patient education and long-term follow-up are important for children who present with a discoid meniscus at a young age or with a complete or Wrisberg type, as these patients may be at increased odds of symptomatic discoid meniscus in the contralateral knee, even several years later. Furthermore, evaluation and treatment of discoid lateral meniscus requires vigilance for meniscal tears.

LEVEL OF EVIDENCE

Prognostic study, level III.

A novel magnetic resonance imaging classification of discoid lateral meniscus based on peripheral attachment

BACKGROUND

In the symptomatic discoid lateral meniscus, the effectiveness of preoperative magnetic resonance imaging (MRI) is not well documented.

HYPOTHESIS

Magnetic resonance imaging classification will provide more information to the surgeon in choosing the appropriate treatment methods with the help of arthroscopic findings.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Sixty-seven patients (82 knees) were reviewed. The preoperative MRI was checked in 76 of 82 knees. The Lysholm and Ikeuchi grading scales were evaluated. Images were analyzed from MRI, and findings were classified into 4 categories: no shift, anterocentral shift, posterocentral shift, and central shift. Tear pattern classifications were based on arthroscopic findings: horizontal tear, peripheral tear, horizontal and peripheral tear, posterolateral corner loss, and others. The correlations between MRI classification tear patterns and surgical methods were analyzed using the chi-square test or the Fisher exact test. The sensitivity, specificity, and accuracy of shift in preoperative MRI-according to the existence of peripheral tear when corroborated with arthroscopy-were also analyzed with the chi-square test. Inter- and intraobserver reliability was statistically analyzed by producing the inter- and intraclass correlation coefficient.

RESULTS

The mean preoperative Lysholm score was 77.3 (range, 43-97), and the last follow-up Lysholm score had increased to 96.8 (range, 84-100; P < .001). At last follow-up (100% follow-up), the Ikeuchi grading scale scored 48 knees as excellent, 30 as good, and 4 as fair. According to the MRI classification, 43 knees were no shift; 6, anterocentral shift; 15, posterocentral shift; and 12, central shift. Shift-type knees had a significantly larger number of peripheral tears, and repairs were performed in the shift-type knees (55%) more frequently than in the no-shift-type knees (28%). Among 82 knees, 31 were repaired simultaneously after a central partial meniscectomy.

CONCLUSION

Magnetic resonance imaging classification provides more information to surgeons in choosing the appropriate treatment methods, although the final decision regarding procedure is made during arthroscopy after thorough analysis of the tear.

The condylar cutoff sign: quantifying lateral femoral condylar hypoplasia in a complete discoid meniscus

We describe the condylar cutoff sign, a radiographic sign in knees with a discoid lateral meniscus, for diagnosis of complete discoid meniscus. We retrospectively reviewed tunnel-view radiographs of 100 patients (100) knees including 50 with complete discoid lateral meniscus and 50 with normal menisci. All patients were 18 years of age or older. All of the knees were arthroscopically examined. We developed a method to measure the prominence of the femoral condyle adjacent to the intercondylar notch on a tunnel view of the knee. The prominence ratio, the ratio of the medial and lateral condylar prominence, was compared and analyzed. The measurements were performed by three observers on two separate occasions to determine reliability. The intraobserver and interobserver variability study revealed high reliability with correlation coefficients ranging from 0.86 to 0.99. Using a cutoff ratio of 0.8, we observed a major difference between the two groups and found the ratio had 76% sensitivity, 96% specificity, 95% positive predictive value, and 80% negative predictive value in every set of measurements. The sign has high specificity and reliability but might not apply to younger patients.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Sonographic evaluation of the injuries after traumatic patellar dislocation in adolescents

BACKGROUND

Traumatic patellar dislocation (TPD) may be associated with other injuries requiring additional treatment. The superficial localization of the knee extensor apparatus and knee articular cartilage make them accessible to sonographic evaluation (ultrasonography [USG]).

PURPOSE OF THE STUDY

Prospective analysis of the value of USG in TPD.

METHODS

In 21 patients, 22 knees were examined by USG after clinical and routine radiographic evaluations. Based on USG findings, operative or nonoperative treatment was done (15 and 7 cases, respectively).

RESULTS

In 17 knees, lesions of the medial patellofemoral ligament (MPFL) fibers were visible. In 16 knees, avulsion fractures of the patellar insertion of the MPFL were identified. Injuries of the femoral attachment of the MPFL or intramuscular hematoma of the vastus medialis obliquus (VMO) were present in 7 knees. Eleven osteochondral loose bodies and 1 nondisplaced osteochondral fracture were detected in 11 knees. Corresponding osteochondral lesions were localized in all cases. An osteochondral loose body that was identified by USG was confirmed intraoperatively or by computed tomographic scan in 91.6%, the osteochondral lesion localization in 81.8%, and avulsion fracture of the patellar attachment of the MPFL in 100% of knees. Overall, the USG findings were confirmed by these methods in 88.2% of knees.

CONCLUSIONS

Ultrasonography is highly efficient in determining the extent of injuries after TPD in adolescents. Ultrasonography allows visualization of loose bodies, localization of osteochondral lesions, and, using a dynamic modification, allows precise assessment of the functional status of the MPFL.

LEVEL OF EVIDENCE

II.

Arthroscopic findings at the time of patellar realignment surgery in adolescents

Articular cartilage injuries and loose bodies have been associated with patellar dislocations. At the time of patellar realignment surgery (PRS), direct intraarticular visualization of the structures of concern may be limited with the use of a small arthrotomy. Concomitant diagnostic arthroscopy can improve the identification of intraarticular abnormalities, both patellofemoral and nonpatellofemoral, because of the better field of view.

PURPOSE

This report details the findings from knee arthroscopy performed concomitantly with PRS in adolescents.

METHODS

All patients underwent knee arthroscopy and open PRS for patellar instability, performed by a single surgeon, during a 4-year period. Patient demographics, knee history, clinical examination, operative findings, and treatment details were collected on all patients.

RESULTS

: Thirty-eight patients (mean age, 14.9 years; 41 knees) were included in this analysis. Patellar osteochondral lesions were present in 30 knees (73%; mean size, 112 mm). Femoral lesions were documented in 11 knees (23%; mean size, 81 mm). Loose bodies were present in 6 knees (15%). In 8 patients (20%), an additional 11 nonpatellofemoral diagnoses were made at the time of arthroscopy: lateral tibiofemoral chondroses (n = 4), medial meniscal tear (n = 2), lateral meniscal tear (n = 2), discoid lateral meniscus (n = 1), partial anterior cruciate ligament tear (n = 1), and medial tibiofemoral chondrosis (n = 1). Because of these findings, 5 additional procedures were performed in 4 patients: partial lateral meniscectomy (n = 2), medial meniscal repair (n = 1), discoid meniscus saucerization (n = 1), and staged distal femoral valgus-correcting osteotomy (n = 1).

CONCLUSIONS

By performing concomitant knee arthroscopy at the time of PRS, we were able to identify significant tibiofemoral abnormality in 4 patients, which would have been missed with direct inspection by a limited arthrotomy at the patellofemoral joint. In addition, precise evaluation of the patellofemoral joint permits customization of the PRS and aids in establishing appropriate patient expectations postoperatively. We advocate diagnostic knee arthroscopy at the time of PRS in adolescents to identify all intraarticular abnormalities and to optimize discussions with the patient and the caregivers on the long-term prognosis of the knee.

SIGNIFICANCE

Arthroscopic inspection of the knee at the time of PRS permits identification of abnormality that is not routinely visual by using open arthrotomy. Twenty percent of patients had additional pathological findings; of these patients, 50% underwent an additional surgical procedure.