Diagnostic performance of clinical examination and selective magnetic resonance imaging in the evaluation of intraarticular knee disorders in children and adolescents

[Ligamentous and meniscal injuries of the pediatric knee joint]

Intraligamentous injuries to the anterior cruciate ligament (ACL) and meniscus injuries are rare in children and adolescents and often occur as a result of sports injuries. Clinically, they usually present as a hemarthrosis. The diagnosis of choice is the MRI examination. Surgical treatment of intraligamentary ACL injuries using the transphyseal technique is now also the gold standard treatment for children and adolescents, leg axis and length checks are necessary after surgery until growth is complete. Meniscus injuries are also addressed surgically. Postoperative follow-up treatment and rehabilitation are particularly important in order to prevent reinjury. The disc meniscus is a special entity and is also treated surgically if it is symptomatic. Isolated collateral ligament and posterior cruciate ligament ruptures are rarities.

Bilateral osteochondritis dissecans of the knee in pediatric and adolescent patients presenting with unilateral symptoms: An epidemiological and radiographic analysis

Purpose

This study aims to determine the prevalence and characteristics of bilateral osteochondritis dissecans of the knee in patients presenting with unilateral symptoms and compare this cohort to patients with unilateral disease.

Methods

Records of patients ≤18 years old from 2003 to 2016 with a diagnosis of osteochondritis dissecans of the knee and strictly unilateral knee pain were identified. Contralateral (asymptomatic) knee imaging within 1 year of initial presentation was required. Lesion characteristics were evaluated by assessing size, location, and Hefti staging. Both surgical and nonoperative treatments were recorded. Patients with unilateral osteochondritis dissecans were compared to those with bilateral disease.

Results

Eighty patients, 63 males (79%) and 17 females (21%), with an average age of 13.1 years old, were included. Twenty (25%) of the presenting/symptomatic lesions were deemed stable on magnetic resonance imaging. A positive correlation between lesion size and Hefti classification was appreciated. Twelve patients (15%) were found to have bilateral osteochondritis dissecans on contralateral imaging. There was no significant difference in skeletal maturity between patients with bilateral versus unilateral disease. Fifty-two patients (77%) with unilateral disease underwent surgical intervention, while 9 (75%) of those with bilateral disease underwent surgery on either knee. In patients with an asymptomatic contralateral lesion, 67% ultimately underwent surgical intervention on the contralateral knee.

Conclusions

In patients presenting with unilateral osteochondritis dissecans symptoms, there was a 15% prevalence of bilateral disease, with no difference in age, sex, physeal status, or lesion characteristics between patients with unilateral vs bilateral osteochondritis dissecans lesions. Given the prevalence of asymptomatic contralateral lesions and the required intervention, this study supports early bilateral radiologic knee evaluation.

Level of evidence

IV, Retrospective Case series.

Evaluation of tibial eminence morphology using magnetic resonance imaging (MRI) in juvenile patients with complete discoid lateral meniscus

Background

Many studies have shown that hypoplasia of knee bone morphology is related to the morphological features of the discoid lateral meniscus (DLM). However, few studies have focused on hypoplasia of tibial eminence morphology in juvenile patients with complete DLM. The purpose of this study was to determine the relationship between tibial eminence morphology characteristics and complete DLM in juvenile patients.

Methods

The DLM group comprised 34 juvenile patients with complete DLM, and the control group comprised 34 juvenile individuals, each with a normal lateral meniscus based on magnetic resonance imaging (MRI) findings. All parameters, including tibial width (TW), tibial eminence width (TEW), the height of the lateral tibial spine (HLTS), the height of the medial tibial spine (HMTS), lateral slope angle of the lateral tibial eminence (LSALTE), lateral slope angle of the medial tibial eminence (LSAMTE), tibial eminence width ratio (TEWR), height of the lateral tibial spine ratio (HLTSR), and the height of the medial tibial spine ratio (HMTSR), were recorded using coronal MR images. Statistical analyses were used to determine the differences between the two groups and whether differences were significant.

Results

The TEW and TEWR were significantly greater (P < 0.05), and LSALTE and LSAMTE were significantly smaller (P < 0.05) in patients in the DLM group than in participants in the control group. Receiver operating characteristic (ROC) analysis revealed that a larger TEW, above 13.4 mm, was associated with complete DLM, with a sensitivity of 77.0% and specificity of 88.2%, and a larger TEWR, above 19.7%, was associated with complete DLM, with a sensitivity of 76.5% and specificity of 91.2%.

Conclusions

MR imaging can be used to diagnose tibial eminence hypoplasia in juvenile patients with complete DLM. Additionally, TEW and TEWR could help clinicians screen for complete DLM in juvenile patients.

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.

Validity of the McMurray Test for Meniscal Tear in Pediatric and Adolescent Patients

OBJECTIVE

The aim of this study was to identify the accuracy of the McMurray test in the adolescent and pediatric population.

DESIGN

Retrospective case series.

SETTING

Tertiary care, institutional.

PATIENTS

Inclusion criteria included patients who presented with unilateral knee pain and were seen by pediatric sports medicine physicians. Patients were excluded if their knee pain was related to any underlying conditions. Three hundred patient charts were reviewed, and 183 patients (age range: 8-18 years, mean: 14 years; 74 male) met the inclusion criteria.

INTERVENTIONS

Symptoms at initial visit (knee pain).

MAIN OUTCOME MEASURES

Presence of a meniscal tear using the McMurray test.

RESULTS

Eighty-four percent (160/191) of patients had a McMurray test documented as performed by the physician, and 17% (27/160) elucidated a positive response. Of 26 patients who had a positive McMurray and underwent magnetic resonance imaging (MRI), 16 (62%) showed a meniscal tear on their MRI. However, of the 87 patients who had a negative McMurray and still underwent MRI, 25 (29%) had a positive meniscal tear. The sensitivity, specificity, positive predictive value, and negative predictive value were 39%, 86%, 62%, and 71%, respectively.

CONCLUSION

In a pediatric and adolescent population, the McMurray test was negative for 61% (23/38) of meniscal tears identified on MRI.

CLINICAL RELEVANCE

Although the test can be a useful tool as a part of a thorough evaluation, combining it with mechanical symptoms, patient history and imaging may be more helpful to diagnose a meniscus tear.

Partial resection of lateral discoid meniscus changes lower limb axial alignment - A retrospective cohort study

AIM

This study aimed to explore the changes in lower limb axial alignment and knee joint function after arthroscopic partial resection of the discoid lateral meniscus.

METHODS

Preoperative and postoperative full-length weight-bearing radiographs of the lower limb were obtained from a total of 161 patients with lateral menisci tears from September 2018 to September 2020 who underwent partial meniscal resection. The patients were divided into discoid meniscus group (DMG) and ordinary meniscus group (OMG). The measured mechanical axis deviation (MAD), proximal tibia angle (PTA), and distal femoral angle (DFA) in the axial alignment of the lower limb were determined before and after surgery. Knee joint function on the affected side was determined using the International Knee Documentation Committee (IKDC) subjective scale and the Lysholm knee scoring scale before surgery and at one, six, 12, and 24 months after surgery.

RESULTS

For MAD and DFA, there were statistically significant differences between the preoperative and postoperative findings within each group (P < 0.01); the MAD and DFA were smaller after surgery. The difference in preoperative and postoperative PTA of the DMG was statistically significant (P < 0.01), meaning that the PTA becomes larger after surgery. The differences in preoperative and postoperative PTA of the OMG, preoperative PTA between the two groups, and postoperative PTA between the two groups were not statistically significant (P > 0.05). Intragroup comparisons of the IKDC subjective scale and the Lysholm knee scoring scale before and after surgery revealed significant differences (P < 0.05).

CONCLUSION

Arthroscopic partial resection of the discoid lateral meniscus is a safe and effective surgical method that can significantly improve knee joint function. Although the axial arrangement of the lower limbs will be slightly changed in the early stage, it will still be within the normal range after surgery in patients with normal lower limb axial alignment. For patients with varus or valgus before surgery, this procedure should be applied with caution.

Diagnostic values of history taking, physical examination and KT-1000 arthrometer for suspect anterior cruciate ligament injuries in children and adolescents: a prospective diagnostic study

Background

Diagnosing anterior cruciate ligament (ACL) injuries in children and adolescents are more challenging compared to adults. Delayed diagnosis may result in meniscal or chondral injuries. The aim of this study was to determine the diagnostic values of history taking, physical examination and KT-1000 arthrometer for suspect ACL injuries in children and adolescents.

Methods

In this prospective diagnostic study, all children and adolescents (< 18 years) with post-traumatic knee complaints presenting at the out-patient department of the Máxima MC were eligible for inclusion. One experienced knee specialised orthopaedic surgeon was blinded and performed history taking, physical examination and KT-1000 arthrometer measurement. All patients had a magnetic resonance imaging (MRI) for the final diagnosis. Diagnostic values of interest were sensitivity, specificity, positive and negative predictive values (PPV and NPV). The outcomes of the KT-1000 arthrometer were drafted in a relative operating characteristics (ROC) curve to determine the optimal cut-off points.

Results

Sixty-six patients were included, of which 50 had an ACL rupture and 16 had no ACL rupture on MRI. Report of a popping sensation during trauma had a specificity and PPV of 100% for diagnosing ACL injuries. The PPV and NPV of the Lachman test (in case of describing end-feel) were 95 and 82%, of the anterior drawer test 87 and 90% and of the pivot shift test 95 and 81% respectively. The optimal cut-off point of the KT-1000 arthrometer at 133 N force was an absolute translation of ≥7 mm with a PPV and NPV of 97 and 88% respectively.

Conclusions

Report of a popping sensation during trauma has a specificity and PPV of 100% for diagnosing ACL injuries in children and adolescents. Although potentially difficult in children, the Lachman test, anterior drawer test and pivot shift test have a high PPV and NPV when performed by an experienced orthopaedic surgeon. An absolute anterior translation of ≥7 mm of the injured knee in the KT-1000 arthrometer at 133 N has the highest diagnostic values of all tests for diagnosing ACL injuries.

Level of evidence

3

Comparison of the Healing Outcomes of Conservative Treatment for Stable Juvenile Osteochondritis Dissecans of the Lateral Femoral Condyle With Normal Lateral Meniscus and Incomplete Discoid Lateral Meniscus

BACKGROUND

This study aimed to compare the healing outcomes of conservative treatment for osteochondritis dissecans (OCD) of the lateral femoral condyle with normal lateral meniscus and incomplete discoid lateral meniscus (DLM).

METHODS

Forty-four knees in 37 juvenile patients (mean age 9.9 y) with stable OCD and whose lateral meniscus shape was normal or incomplete DLM were enrolled. All patients underwent conservative treatment with physical activities prohibited. For each lateral meniscus group, patient demographics including pretreatment Tegner activity scale, OCD stage, and Lysholm score, radiographic healing status; complete or incomplete healing at 3 months, 6 months, and 1 year, time to complete healing and post-treatment clinical scores were evaluated.

RESULTS

There were 21 (47.8%) and 23 (52.3%) knees with normal menisci and incomplete DLM, respectively. At 3 months, 6 months, and 1 year after conservative treatment, healed OCD status was noted in 3 (14.3%), 12 (57.1%), and 19 (90.5%) knees of the normal type and in 3 (13.0%), 12 (52.2%), and 20 (86.9%) knees of the incomplete DLM type, respectively (P>0.05). The mean time to healing in each group was 198 and 181 days, respectively. No significant differences in terms of OCD healing rate at each time, time to healing, and post-treatment clinical scores were found between the groups.

CONCLUSION

No significant differences in the OCD healing rate or time to healing were found between the normal and incomplete DLM type. Therefore, treatment strategy for OCD with stable and asymptomatic incomplete DLM should be the same as that for those occurring with a normal meniscus.

[Management status of anterior cruciate ligament injury in children and adolescents]

OBJECTIVE

To summarize the current management of anterior cruciate ligament (ACL) injury in children and adolescents, in order to provide reference for the management of ACL injury in children and adolescents.

METHODS

The relevant literature at home and abroad in recent years was extensively accessed to summarize the management status of ACL injury in children and adolescent.

RESULTS

The number of ACL injury in children and adolescents is increasing every year. The diagnosis of ACL mainly depends on symptoms and signs. Rehabilitation, physeal-sparing techniques, partial transphyseal techniques, all-epiphyseal techniques, and transphyseal techniques are used to treat ACL injury in children and adolescents.

CONCLUSION

Dynamic monitoring of knee joint in children and adolescents should be strengthened. The best treatment for ACL injury in children and adolescents is selected according to the patients' actual age, bone age, Tanner stage, and physiological conditions such as menstruation, body growth speed, and other characteristics.

Diagnostic Performance of MRI Versus CT in the Evaluation of Intra-articular Osteochondral Fracture in Pediatric Patients With Acute Traumatic Lateral Patellar Dislocation

Background:

Evaluation of intra-articular osteochondral fractures in children with acute traumatic lateral patellar dislocation (LPD) is important for determining treatment options.

Purpose:

To (1) compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) for evaluating intra-articular osteochondral fractures; (2) compare the interpretation of CT and MRI images between radiologists and pediatric orthopaedic surgeons (POS); and (3) investigate any clinical factors influencing the accuracy of CT and MRI evaluations.

Study Design:

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

Methods:

We reviewed 35 knees in 35 patients (mean age, 12.2 ± 1.2 years; 12 boys and 23 girls) who were treated arthroscopically for acute traumatic LPD; 71% of the patients had patellar fractures, 54% had femoral fractures, and 60% had free osteochondral fracture fragments. All presurgical MRI and CT images were reviewed by POS who were blinded to both the reports of the radiologists and surgical records. We compared the accuracy of CT and MRI in diagnosing intra-articular osteochondral fractures against the arthroscopic findings and compared the interpretation of the images by the POS (MRI-O, CT-O) with those of the radiologists (MRI-R, CT-R).

Results:

There was no significant difference in diagnostic accuracy between CT and MRI for overall intra-articular osteochondral fractures by the POS or the radiologists; however, the CT-O images had a higher diagnostic specificity (84.2% vs 69.6%; P < .001) and sensitivity (88.1% vs 70.1%; P < .001) versus the MRI-R images. Regarding free fracture fragments, the CT-R images had a higher diagnostic accuracy than the MRI-R images (73.5% vs 47.1%; P = .026). When backed by clinical data, the MRI-O images had greater diagnostic accuracy (78.7% vs 60.3%; P = .001) and sensitivity (88.1% vs 30.7%; P = .021) but lower specificity compared with the MRI-R images, and the CT-O images had similar diagnostic accuracy but greater sensitivity than the CT-R images (70.1% vs 52.2%; P < .001). The diagnostic accuracy of MRI-O images was lower for children under 12 years versus children 12 years and over (67.5% vs 83.3%; P = .040).

Conclusion:

Compared with MRI, CT scans had better diagnostic performance in the evaluation of intra-articular osteochondral fractures in pediatric patients with acute traumatic LPD. Clinical data enhanced the diagnostic sensitivity of MRI and CT but decreased the specificity of MRI. MRI evaluations remain challenging for both POS and radiologists.

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.

Juvenile Osteochondritis Dissecans of the Knee Joint: Midterm Clinical and MRI Outcomes of Arthroscopic Retrograde Drilling and Internal Fixation with Bioabsorbable Pins

OBJECTIVE

This study aimed to assess the clinical and radiographic outcomes of juvenile patients who suffered from stage II or III osteochondritis dissecans (OCD) of the knee and underwent arthroscopic retrograde drilling and internal fixation with bioabsorbable pins.

DESIGN

Medical and radiological records from patients aged 11 to 16 years, who underwent arthroscopic treatment for OCD lesions of the knee in 2 tertiary hospitals, were retrospectively reviewed. The procedure was indicated by persistent pain and by magnetic resonance imaging (MRI). All patients underwent retrograde drilling and arthroscopic fixation of the lesion with bioabsorbable pins. MRI was conducted at least 1 year postoperative in all patients to evaluate healing. Functional outcomes were evaluated through the Visual Analogue Scale (VAS) for pain, Lysholm, and IKDC (International Knee Documentation Committee) scores.

RESULTS

A total of 40 patients, with an average age of 13.1 years (range = 11-16 years) and an average follow-up of 6.6 years (range = 3-13 years) were reviewed. MRI findings confirmed the healing of the lesion in 36 out of the 40 (90%) patients. In particular, the healing rate was 95% (20/21) and 84% (16/19) for stage II and stage III, respectively. Lysholm, IKDC, and VAS scores revealed a statistically significant improvement (P < 0.05) at final follow-up in comparison to preoperative status. No infection, knee stiffness, or other complication was recorded.

CONCLUSIONS

Retrograde drilling combined with internal fixation with bioabsorbable pins, of stages II and III OCD lesions of the knee provides good to excellent outcomes to juvenile patients, with a high healing rate.

Surgical Management of Medial Discoid Meniscus in Pediatric and Adolescent Patients

BACKGROUND

Medial discoid meniscus (MDM) is an exceedingly rare anatomic abnormality that presents similarly to other meniscal pathologies. Symptomatic MDM is typically managed arthroscopically with mixed short-term and long-term outcomes, although the existing knowledge about MDM is limited. The purpose of this study was to describe the presentation and surgical treatment of MDM in pediatric and adolescent patients.

METHODS

Medical records of 12 knees with MDM in 8 pediatric and adolescent patients treated between 1991 and 2016 were reviewed retrospectively for patient characteristics, clinical manifestations, radiographic findings, operative techniques, and surgical outcomes.

RESULTS

Of the 446 knees diagnosed arthroscopically with discoid menisci, lateral discoid meniscus was noted in 434 knees (97.3%) and MDM was present in 12 knees (2.7%). The MDM series included 8 patients of mean age 13.8 years (range: 7.8 to 19.8), of which 5 were males (63%), and 4 (50%) had bilateral involvement. Of the 11 knees with available clinical records, all cases presented symptomatically (pain, mechanical symptoms); 10 (91%) had concurrent physical exam findings. On intraoperative examination, discoid morphologies were described as complete in 4/8 knees (50%) or incomplete in 4/8 (50%), with associated instability in 6/12 (50%). Meniscal tears were reported in 9 cases (75%)-primarily, horizontal cleavage tears. Saucerization was performed in 11 knees (92%), with medial meniscal repair in 7 (58%), when indicated. Retear of the medial meniscus occurred in 4/11 knees (36%) at a mean of 25.8 months postoperation; 2 knees required revisions. One knee developed arthrofibrosis and underwent arthroscopic lysis of adhesions.

CONCLUSIONS

MDM is a rare diagnosis, representing 3% of all discoid menisci, with a nonspecific clinical manifestation. Operative management of symptomatic MDM typically involves saucerization and meniscal repair, when indicated, for concurrent tears. Symptom resolution is common short-term, but long-term outcomes include recurrent meniscal tears. Subsequent observational studies are important to evaluate long-term outcomes, such as arthritic changes, with the advancement of arthroscopic techniques for meniscal preservation.

LEVEL OF EVIDENCE

Level IV-retrospective case series.

A Useful MRI Classification for Symptomatic Discoid Lateral Meniscus

Purpose

The purpose of this study is to classify the discoid lateral meniscus (DLM) according to the signal and shape in magnetic resonance imaging (MRI), and to provide information not only in diagnosis but also in treatment.

Materials and Methods

We reviewed 162 cases who diagnosed with DLM by MRI and underwent arthroscopic procedures from April 2010 to March 2018. Three observers reviewed MRI findings of all cases and predicted arthroscopic tear using three MRI criteria (criterion 1,2 and 3). Among three criteria, the criterion that most accurately predicts arthroscopic tear was selected. Using this criterion, the cases of predicted tear were named group 1. In addition, group 1 was divided into three subgroups (group 1a, 1b and 1c) by deformation or displacement on MRI and arthroscopic type of tear and procedures were analyzed according to these subgroups.

Results

The intra-meniscal signal change itself (criterion 3) on MRI showed the highest agreement with the arthroscopic tear. No meniscal deformation and displacement on MRI (group 1a) showed no specific type of tear and more cases of meniscal saucerization. The meniscal deformation on MRI (group 1b) showed more simple horizontal tears and more cases of meniscal saucerization. The meniscal displacement on MRI (group 1c) showed more peripheral tears and more cases of meniscal repair and subtotal meniscectomy. Comparing arthroscopic type of tear and type of arthroscopic procedure between three subgroups, there were significant differences in three groups (P < .05).

Conclusions

Intra-meniscal signal change itself on MRI is the most accurate finding to predict arthroscopic tear in symptomatic DLM. In addition, subgroup analysis by deformation or displacement on MRI is helpful to predict the type of arthroscopic tear and procedures.

Symptomatic Discoid Meniscus in Children and Adolescents: A Review of 470 Cases

BACKGROUND

Discoid meniscus is a congenital variant, typically involving the lateral meniscus, that comprises a spectrum of meniscal shapes and degrees of instability in an estimated 1% to 15% of the population. The purpose of this study was to describe the clinical and operative course of a large cohort of children and adolescents patients with symptomatic lateral discoid meniscus.

METHODS

Medical records of 470 knees with symptomatic lateral discoid meniscus in 401 patients ages 18 years or younger diagnosed at a single institution between 1991 and 2016 were reviewed retrospectively for patient characteristics, treatment course (nonoperative and/or operative), and complications. Surgical reports were reviewed in the operative group.

RESULTS

The series included 401 patients of mean age 11.6 years (range: 1 mo-18.9 y), of which 222 (55%) were female, and 69 (17%) had bilateral involvement. Of 470 knees, 83 (18%) were initially managed nonoperatively. Of these, 32 knees (39%) failed nonoperative management and were converted to surgical treatment at a median of 7.9 months (interquartile range: 4.0-15.1). In total, 419 knees were managed surgically with saucerization (partial meniscectomy) with or without meniscal repair/stabilization; 84 knees (20%) required at least one concurrent nonmeniscal procedure. Discoid meniscus tears were reported in 264/419 knees (63%) intraoperatively; horizontal cleavage tears were most common. Reoperation was required for 66/379 cases (17%) with clinical follow-up, at a median of 19.6 months (range: 9.2-34.9) after index saucerization; 60/379 cases (16%) had ongoing pain and/or mechanical symptoms at final follow-up.

CONCLUSION

With a failure rate of 39% (32/83 knees), nonoperative management for discoid lateral meniscus frequently convert to surgical treatment. During surgery, meniscus tearing and instability are common and should be anticipated. Postoperatively, 33% (126/379) of knees with clinical follow-up underwent either reoperation, or had ongoing symptoms of the knee at final follow-up. Discoid mensical retear is the most common complication (94%, 62/66) prompting repeat surgery, and should be discussed with families before the index operation.

LEVEL OF EVIDENCE

Level IV-descriptive case series.

Acute Knee Injuries in Children and Adolescents: A Review

IMPORTANCE

Knee injuries in children and adolescents are exceedingly common. When an active youth presents complaining of knee pain, the treating pediatrician should be comfortable with forming a working differential diagnosis and should be able to manage many such injuries or recognize when it is necessary to make an appropriate referral.

OBSERVATIONS

Knee injuries typically present after acute trauma. Appreciating the likely etiologies pertaining to a particular case is best achieved with a thorough history and physical examination. This review discusses the etiologies of acute injuries including fractures that are unique to skeletally immature individuals, patellar dislocations, ligamentous injuries, and meniscal tears. Imaging findings and management of these conditions are also reviewed.

CONCLUSIONS AND RELEVANCE

This review summarizes the more common acute knee injuries seen in active children and adolescents. Given how frequently such conditions present, this overview of diagnosis and management will provide a useful resource for the nonspecialist.

Discoid lateral meniscus: importance, diagnosis, and treatment

Discoid lateral meniscus (DLM) is a common anatomic variant in the knee typically presented in young populations, with a greater incidence in the Asian population than in other populations. As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. Snapping and pain are common symptoms, with occasional limitations of extension, in patients with DLM. Examination of the contralateral knee is necessary as DLM affects both knees. While simple radiographs may provide indirect signs of a DLM, magnetic resonance imaging (MRI) is essential for diagnosis and treatment planning. Although DLM was traditionally classified into three categories, namely, complete, incomplete, and Wrisberg DLM, a recent MRI classification provides useful information for surgical planning because the MRI classification was based on the peripheral detachment in patients with DLM, as follows: no shift, anterocentral shift, posterocentral shift, and central shift. Asymptomatic patients require close follow-up without surgical treatment, while patients with symptoms often require surgery. Total or subtotal meniscectomy, which has been traditionally performed, leads to an increased risk of degenerative arthritis; thus, partial meniscectomy is currently considered the treatment of choice for DLM. In addition to partial meniscectomy, meniscal repair of peripheral detachment is recommended for stabilization in patients with DLM to preserve the function of the meniscus. Previous studies have reported that partial meniscectomy with or without meniscal repair is effective and shows superior clinical and radiological outcomes to those of total or subtotal meniscectomy during the short- to long-term follow-up. Our preferred principle for DLM treatment is reduction, followed by reshaping with reference to the midbody of the medial meniscus and repair as firm as possible.

Discoid lateral meniscus: current concepts

The discoid meniscus is a congenital morphological abnormality encountered far more commonly on the lateral than the medial side. The discoid lateral meniscus (DLM) is more prevalent in Asia with an incidence of 10%-13%, than in the Western world with an incidence of 3%-5%. DLM can be bilateral in more than 80% cases. Due to its abnormal shape and size, the discoid meniscus is prone to tearing and has an impact on gait mechanics. The discoid meniscus has deranged collagen arrangement and vascularity which can have implications for healing after a repair. Patients with a DLM may or may not be symptomatic with mechanical complaints of locking, clicking, snapping or pain. Symptoms often arise due to a tear in the body of the meniscus or a peripheral detachment. Asymptomatic patients usually do not require any treatment, while symptomatic patients who do not have locking are managed conservatively. When a peripheral detachment is present, it must be stabilised while preserving the meniscus rim to allow transmission of hoop stresses. Rehabilitation after surgery is highly individualised and return to sports is possible after more than 4 months in those undergoing a repair. The functional outcomes and onset of radiographic arthritis after saucerisation and repairing a discoid meniscus are better in the long term, compared with a subtotal meniscectomy. However, there is no compelling evidence currently favouring a repair as results deteriorate with increasing follow-up. Poor prognosis is reported in patients undergoing a total meniscectomy, a higher age at presentation and valgus malalignment.

Concomitant Posterolateral Corner Injuries in Skeletally Immature Patients With Acute Anterior Cruciate Ligament Injuries

BACKGROUND

Missed posterolateral corner (PLC) injuries are a known cause of anterior cruciate ligament reconstruction (ACL) failure in the adult population. Failed ACL reconstruction causes significant morbidity in the skeletally immature pediatric population. There is little literature on the character and potential significance of PLC injuries in skeletally immature patients.

METHODS

Magnetic resonance imaging studies of the knee at a tertiary care children's hospital for patients who underwent an ACL reconstruction without PLC surgery were retrospectively reviewed. Demographic variables were obtained through chart review, and magnetic resonance imaging studies were evaluated for PLC (popliteus, fibular collateral ligament, popliteofibular ligament, and arcuate ligament) injury, and ACL, medial collateral ligament (MCL), bone bruise, fracture, and meniscal pathology by an experienced pediatric musculoskeletal radiologist.

RESULTS

A total of 50 patients with a mean age at 13.3 years at injury were analyzed. PLC injuries were found in 26 patients (52%), with 7 patients (14%) having a complete tear of a component of the PLC. There was no association between sex (P=0.35), Segond fracture (P=0.09), meniscus injury (P=0.92), or MCL injury (P=0.24) with the risk of PLC injury. There was an association between patient age and PLC injury (P=0.02). For each additional year of age, the odds of PLC injury increased by 1.8 times (odds ratio, 1.8; 95% confidence interval, 1.4-2.2). There was no association between PLC injury and ACL graft failure (P=0.19).

CONCLUSIONS

Missed PLC injuries are a significant source of morbidity and poor clinical outcomes in the management of concomitant ACL injuries in adults. This study demonstrates the prevalence of PLC injuries in the setting of concomitant ACL injuries in the unique skeletally immature patient population. Incomplete PLC injuries are relatively common. Complete PLC injuries are relatively uncommon. PLC injury was more common in older patients. No other concomitant injury predicted the likelihood of PLC injury. Further research is needed regarding the risk of ACL reconstruction failure from associated PLC injury and the indications for PLC reconstruction in skeletally immature patients.

LEVEL OF EVIDENCE

Level IV-diagnostic study.

Osteochondritis Dissecans of the Knee: An Interrater Reliability Study of Magnetic Resonance Imaging Characteristics

BACKGROUND

Imaging characteristics of osteochondritis dissecans (OCD) lesions quantified by magnetic resonance imaging (MRI) are often used to inform treatment and prognosis. However, the interrater reliability of clinician-driven MRI-based assessment of OCD lesions is not well documented.

PURPOSE

To determine the interrater reliability of several historical and novel MRI-derived characteristics of OCD of the knee in children.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

A total of 42 OCD lesions were evaluated by 10 fellowship-trained orthopaedic surgeons using 31 different MRI characteristics, characterizing lesion size and location, condylar size, cartilage status, the interface between parent and progeny bone, and features of both the parent and the progeny bone. Interrater reliability was determined via intraclass correlation coefficients (ICCs) with 2-way random modeling, Fleiss kappa, or Krippendorff alpha as appropriate for each variable.

RESULTS

Raters were reliable when the lesion was measured in the coronal plane (ICC, 0.77). Almost perfect agreement was achieved for condylar size (ICC, 0.93), substantial agreement for physeal patency (ICC, 0.79), and moderate agreement for joint effusion (ICC, 0.56) and cartilage status (ICC, 0.50). Overall, raters showed significant variability regarding interface characteristics (ICC, 0.25), progeny (ICC range, 0.03 to 0.62), and parent bone measurements and qualities (ICC range, -0.02 to 0.65), with reliability being moderate at best for these measurements.

CONCLUSION

This multicenter study determined the interrater reliability of MRI characteristics of OCD lesions in children. Although several measurements provided acceptable reliability, many MRI features of OCD that inform treatment decisions were unreliable. Further work will be needed to refine the unreliable characteristics and to assess the ability of those reliable characteristics to predict clinical lesion instability and prognosis.

Discoid meniscus: current concepts

Discoid meniscus is the most frequent congenital malformation of the menisci, and primarily affects the lateral meniscus; it is highly prevalent in the Asian population.The anatomic, vascular, and ultrastructural features of the discoid meniscus make it susceptible to complex tears.Discoid meniscus anomalies are described according to their shape; however, there is consensus that peripheral stability of the meniscus should also be defined.Initial workup includes plain X-rays and magnetic resonance imaging, while arthroscopic evaluation confirms shape and stability of the meniscus.Clinical presentation is highly variable, depending on shape, associated hypermobility, and concomitant meniscal tears.Treatment seeks to re-establish typical anatomy using saucerization, tear reparation, and stable fixation of the meniscus. Cite this article: EFORT Open Rev 2020;5:371-379. DOI: 10.1302/2058-5241.5.190023.

Joint laxity varies in response to partial and complete anterior cruciate ligament injuries throughout skeletal growth

Anterior cruciate ligament (ACL) injuries are increasingly common in the skeletally immature population. As such there is a need to increase our understanding of the biomechanical function of the joint following partial and complete ACL injury during skeletal growth. In this work, we aimed to assess changes in knee kinematics and loading of the remaining soft tissues following both partial and complete ACL injury in a porcine model. To do so, we applied anterior-posterior tibial loads and varus-valgus moments to stifle joints of female pigs ranging from early juvenile to late adolescent ages and assessed both kinematics and in-situ loads carried in the bundles of the ACL and other soft tissues including the collateral ligaments and the menisci. Partial ACL injury led to increased anterior tibial translation only in late adolescence and small increases in varus-valgus rotation at all ages. Complete ACL injury led to substantial increases in translation and rotation at all ages. At all ages, the medial collateral ligament and the medial meniscus combined to resist the majority of applied anterior tibial load following complete ACL transection. Across all ages and flexion angles, the contribution of the MCL ranged from 45 to 90% of the anterior load and the contribution of the medial meniscus ranged from 14 to 35% of the anterior load. These findings add to our current understanding of age-specific functional properties of both healthy and injured knees during skeletal growth.

In Situ Joint Stiffness Increases During Skeletal Growth but Decreases Following Partial and Complete Anterior Cruciate Ligament Injury

Partial and complete anterior cruciate ligament (ACL) injuries occur in both pediatric and adult populations and can result in loss of joint stability and function. The sigmoidal shape of knee joint function (load-translation curve) under applied loads includes a low-load region (described by slack length) followed by a high-load region (described by stiffness). However, the impact of age and injury on these parameters is not fully understood. The current objective was to measure the effects of age and injury on the shape of joint function in a porcine model. In response to an applied anterior-posterior tibial load, in situ slack did not change (p > 0.05), despite sevenfold increases in joint size with increasing age. Joint stiffness increased from an average of 10 N/mm in early youth to 47 N/mm in late adolescence (p < 0.05). In situ ACL stiffness increased similarly, and changes in in situ joint stiffness and ACL stiffness were highly correlated across ages. With complete ACL injury, in situ slack length increased by twofold to fourfold and in situ stiffness decreased threefold to fourfold across ages (p < 0.05). Partial ACL injury resulted in less dramatic, but statistically significant, increases in joint slack and significant decreases in in situ joint stiffness in the adolescent age groups (p < 0.05). This work furthers our understanding of the interaction between joint biomechanics and ACL function throughout growth and the impact of ACL injury in the skeletally immature joint.

Knee Pathology in Young Adults After Pediatric Anterior Cruciate Ligament Injury: A Prospective Case Series of 47 Patients With a Mean 9.5-Year Follow-up

BACKGROUND

The rate of secondary knee injuries after pediatric anterior cruciate ligament (ACL) injury is uncertain, and previous studies are limited because of poor methodology.

PURPOSE

To evaluate the incidence of new meniscal injuries since the initial diagnostic magnetic resonance imaging (MRI) of young adults who sustained a pediatric ACL injury. In addition, to evaluate meniscal and cartilage injuries in the index knee and contralateral knee injuries on MRI at final follow-up (9.5 years). Furthermore, to assess leg length and alignment based on long-leg radiographs.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Study population at final follow-up included 47 young adults who sustained a pediatric ACL injury before age 13 years. They were followed prospectively since the time of injury for a mean 9.5 years at final follow-up. Imaging included diagnostic MRI of the index knee and 3.0-T MRI of both knees at 1-, 2-, and 9.5-year follow-up, in addition to long-leg radiographs at final follow-up. Forty-three patients underwent active rehabilitation without ACL reconstruction initially; 4 were treated with initial ACL reconstruction. At final follow-up, 27 (57%) had undergone ACL reconstruction.

RESULTS

Fourteen patients had meniscal tears in the index knee at final follow-up (prevalence, 30%). The majority of these were in the same location as previously repaired tears (n = 9). Between diagnostic MRI and final follow-up, 16 patients had sustained new meniscal tears to a healthy meniscus (incidence, 34%). At final follow-up, meniscal injuries recorded at baseline or during follow-up were no longer visible and appeared healed in 17 patients (20 tears). MRI at final follow-up showed cartilage injuries in the index knee of 13 patients (28%) and contralateral injuries in 8 patients (meniscus, n = 2; cartilage, n = 5; subchondral fracture, n = 1). Two patients had a leg-length difference >15 mm, and 3 had side-to-side difference in knee alignment >5°.

CONCLUSION

The incidence of new meniscal tears after pediatric ACL injury was 34% during a mean follow-up period of 9.5 years. At final follow-up, 27 patients (57%) had normal menisci, and none had developed knee osteoarthritis. Primary active rehabilitation, close follow-up, and delayed surgery if needed may be a viable and safe treatment option for some pediatric ACL injuries.

Coping With Anterior Cruciate Ligament Injury From Childhood to Maturation: A Prospective Case Series of 44 Patients With Mean 8 Years' Follow-up

BACKGROUND

There is no consensus regarding the best treatment approach for skeletally immature children with anterior cruciate ligament (ACL) injuries. High-quality studies with long-term follow-up are lacking, and evidence to support decision making is limited.

PURPOSE

To evaluate functional and patient-reported outcome, surgical history, and complications among young adults who sustained an ACL injury before the age of 13 years and were treated with active rehabilitation and the option of delayed ACL reconstruction if needed.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Forty-six children aged <13 years with a total intrasubstance ACL injury were included. None of these patients had additional injuries that warranted early surgery. At final follow-up at a mean 8 years after the time of injury, 44 patients remained in the study. The same test battery was conducted at baseline, 1 and 2 years, and final follow-up at approximately 18 years of age. The test battery included functional tests (hop tests and isokinetic muscle strength tests of quadriceps and hamstrings), patient-reported outcome measures (including the Knee injury and Osteoarthritis Outcome Score and the International Knee Documentation Committee Subjective Knee Form), and clinical examination. Medical records were reviewed to assess surgical history and complications.

RESULTS

At a mean 8 years of follow-up, 24 patients (55%) had undergone ACL reconstruction, and 16 (36%) had undergone meniscal surgery. Quadriceps muscle strength symmetry was >90% for 30 patients (68%). Mean leg symmetry indexes for hop and strength tests were consistently >90%, except for the single-hop test and hamstrings muscle strength for ACL-reconstructed knees. Mean ± SD International Knee Documentation Committee scores were 86.3 ± 13.7 for the ACL-reconstructed knees and 90.6 ± 11.8 for the nonreconstructed knees. At final follow-up, forty patients (91%) remained active in sports, but 29 (66%) restricted their activity level to nonpivoting sports.

CONCLUSION

Active rehabilitation may have a role in treatment of children with ACL injury. Approximately 50% of children may cope well, even to adulthood, without a surgical intervention. The other half may develop instability that warrants ACL reconstruction, and one-third may require meniscal surgery.

Pediatric Anterior Cruciate Ligament Reconstruction

The rate of anterior cruciate ligament (ACL) ruptures diagnosed among the pediatric and adolescent population is increasing. The rise in ACL injuries may be attributed to earlier sports specialization, year-round sports participation, increased awareness, and improved ability to diagnose the injury. Treatment options for pediatric or adolescent ACL injuries include nonoperative conservative treatment, ACL repair, or various techniques for ACL reconstruction. The best course of treatment for ACL rupture in young patients continues to be debated. Anterior cruciate ligament reconstruction with autograft is currently the gold standard and has been shown to be successful in restoring joint stability. This article reviews predisposing factors, common mechanisms, diagnostic procedures, and treatments for ACL rupture in adolescent patients, with a focus on using quadriceps patellar tendon autograft. [Orthopedics. 2018; 41(3):129-134.].

Kinematic features in patients with lateral discoid meniscus injury during walking

At present, there few studies on the kinematic features of lateral discoid meniscus injury. In this study, a motion capture system was used to investigate the motion characteristics of knees with lateral discoid meniscus after injury, and the differences between the knees with lateral meniscus and intact knees were compared. Fourteen patients diagnosed with unilateral lateral discoid meniscus injury, fourteen patients diagnosed with unilateral lateral meniscus injury, and fourteen normal subjects with healthy knees were recruited and grouped. Through kinematic gait analysis, it was found that the subjects in the two groups with meniscus injuries exhibited significantly smaller ranges of rotation and translation than those with healthy knees on the sagittal, coronal, and horizontal planes, but not in proximal-distal translation. Maximum lateral tibial translation and maximum internal tibial rotation in the knees with lateral discoid meniscus injury were significantly decreased compared to those with lateral meniscus injury. The results show that the kinematic features of knees with lateral discoid meniscus injury are statistically different than those of healthy knees and knees with lateral meniscus injury. This study provides an important reference for the dynamic function of knees with lateral discoid meniscus injury.

2018 International Olympic Committee Consensus Statement on Prevention, Diagnosis, and Management of Pediatric Anterior Cruciate Ligament Injuries

In October 2017, the International Olympic Committee hosted an international expert group of physical therapists and orthopaedic surgeons who specialize in treating and researching pediatric anterior cruciate ligament (ACL) injuries. The purpose of this meeting was to provide a comprehensive, evidence-informed summary to support the clinician and help children with ACL injury and their parents/guardians make the best possible decisions. Representatives from the following societies attended: American Orthopaedic Society for Sports Medicine; European Paediatric Orthopaedic Society; European Society for Sports Traumatology, Knee Surgery, and Arthroscopy; International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; Pediatric Orthopaedic Society of North America; and Sociedad Latinoamericana de Artroscopia, Rodilla, y Deporte. Physical therapists and orthopaedic surgeons with clinical and research experience in the field and an ethics expert with substantial experience in the area of sports injuries also participated. This consensus statement addresses 6 fundamental clinical questions regarding the prevention, diagnosis, and management of pediatric ACL injuries. Injury management is challenging in the current landscape of clinical uncertainty and limited scientific knowledge. Injury management decisions also occur against the backdrop of the complexity of shared decision making with children and the potential long-term ramifications of the injury.

2018 International Olympic Committee consensus statement on prevention, diagnosis and management of paediatric anterior cruciate ligament (ACL) injuries

In October 2017, the International Olympic Committee hosted an international expert group of physiotherapists and orthopaedic surgeons who specialise in treating and researching paediatric ACL injuries. Representatives from the American Orthopaedic Society for Sports Medicine, European Paediatric Orthopaedic Society, European Society for Sports Traumatology, Knee Surgery & Arthroscopy, International Society of Arthroscopy Knee Surgery and Orthopaedic Sports Medicine, Pediatric Orthopaedic Society of North America and Sociedad Latinoamericana de Artroscopia, Rodilla y Deporte attended. Physiotherapists and orthopaedic surgeons with clinical and research experience in the field, and an ethics expert with substantial experience in the area of sports injuries also participated. Injury management is challenging in the current landscape of clinical uncertainty and limited scientific knowledge. Injury management decisions also occur against the backdrop of the complexity of shared decision-making with children and the potential long-term ramifications of the injury. This consensus statement addresses six fundamental clinical questions regarding the prevention, diagnosis and management of paediatric ACL injuries. The aim of this consensus statement is to provide a comprehensive, evidence-informed summary to support the clinician, and help children with ACL injury and their parents/guardians make the best possible decisions.

Challenges in the Management of Anterior Cruciate Ligament Ruptures in Skeletally Immature Patients

Although initially considered rare, anterior cruciate ligament (ACL) ruptures in pediatric patients recently have increased substantially as a result of greater awareness of the injury and increased participation in youth sports. Although pediatric patients with an ACL injury and a clinically stable joint may handle the injury well and return to sports activity without requiring surgical reconstruction, young, active patients with an ACL rupture and an unstable joint may be good candidates for ACL reconstruction to prevent ongoing instability and additional joint damage. ACL reconstruction techniques have been developed to prevent physeal injury in skeletally immature patients. The surgical treatment of skeletally immature patients with an ACL rupture may differ from that of adults with an ACL rupture and presents unique challenges with regard to reconstruction technique selection, graft preparation, rehabilitation, and return to sports activity. Orthopaedic surgeons should understand various physeal-sparing ACL reconstruction techniques and the general challenges associated with the surgical management of ACL ruptures in pediatric patients.

2018 International Olympic Committee consensus statement on prevention, diagnosis and management of paediatric anterior cruciate ligament (ACL) injuries

In October 2017, the International Olympic Committee hosted an international expert group of physiotherapists and orthopaedic surgeons who specialise in treating and researching paediatric anterior cruciate ligament (ACL) injuries. Representatives from the American Orthopaedic Society for Sports Medicine, European Paediatric Orthopaedic Society, European Society for Sports Traumatology, Knee Surgery and Arthroscopy, International Society of Arthroscopy Knee Surgery and Orthopaedic Sports Medicine, Pediatric Orthopaedic Society of North America, and Sociedad Latinoamericana de Artroscopia, Rodilla y Deporte attended. Physiotherapists and orthopaedic surgeons with clinical and research experience in the field, and an ethics expert with substantial experience in the area of sports injuries also participated. Injury management is challenging in the current landscape of clinical uncertainty and limited scientific knowledge. Injury management decisions also occur against the backdrop of the complexity of shared decision-making with children and the potential long-term ramifications of the injury. This consensus statement addresses six fundamental clinical questions regarding the prevention, diagnosis, and management of paediatric ACL injuries. The aim of this consensus statement is to provide a comprehensive, evidence-informed summary to support the clinician, and help children with ACL injury and their parents/guardians make the best possible decisions.

Discoid Lateral Meniscus in Children: Diagnosis, Management, and Outcomes

Discoid meniscus is a congenital variant of the knee joint that typically involves abnormal morphology and potential instability of the lateral meniscus. Some discoid menisci have abnormal peripheral attachments and are unstable. Discoid menisci are prone to tearing secondary to increased thickness, poor tissue quality, and instability. Patients may or may not be symptomatic. Torn or unstable discoid menisci cause mechanical symptoms, pain, and swelling. Symptomatic patients in whom nonsurgical management fails most frequently are treated with arthroscopic surgery. Historically, complete meniscectomy has successfully alleviated symptoms but has resulted in poor midterm results, with degenerative changes to the knee joint. Current treatment emphasizes the saucerization of the meniscus, with removal of the central disk and retention of the peripheral crescent. Peripheral meniscal repair is performed when instability is present. Short-term results are good; however, degenerative changes have been reported at intermediate follow-up.

Physical Examination of the Knee: Meniscus, Cartilage, and Patellofemoral Conditions

The knee is one of the most commonly injured joints in the body. Its superficial anatomy enables diagnosis of the injury through a thorough history and physical examination. Examination techniques for the knee described decades ago are still useful, as are more recently developed tests. Proper use of these techniques requires understanding of the anatomy and biomechanical principles of the knee as well as the pathophysiology of the injuries, including tears to the menisci and extensor mechanism, patellofemoral conditions, and osteochondritis dissecans. Nevertheless, the clinical validity and accuracy of the diagnostic tests vary. Advanced imaging studies may be useful adjuncts.

Meniscal injuries in children and adolescents undergoing surgical treatment for tibial eminence fractures

PURPOSE

To prospectively evaluate the prevalence and characteristics of meniscal injuries in children and adolescents undergoing surgical treatment for tibial eminence fractures and to test for possible relationships between associated meniscal lesions and patient demographics or injury characteristics.

METHODS

A prospective multicenter study was conducted to arthroscopically assess the prevalence and characteristics of meniscal injuries in children and adolescents undergoing surgical treatment for tibial eminence fractures between 04/2014 and 10/2015. Patient demographics and injury characteristics were assessed preoperatively. The presence of a meniscal injury was evaluated arthroscopically and characterized according to tear type and location (Cooper classification). Patients with and without meniscal injuries were compared with regard to sex, age, height, weight, BMI, type of injury, mechanism of injury, time to surgery, Tanner stage, sexual maturity (prepubescent vs. pubescent), and modified Meyers and McKeever classification.

RESULTS

A total of 54 consecutive patients (65 % males, mean age: 12.5 ± 3.2 years) were enrolled. Meniscal injury were found in 20 patients (37 %). The lateral meniscus was involved in 18 patients (90 % of all meniscus injuries) and the medial meniscus in 2 patients (10 % of all meniscus injuries). The most common tear pattern was a longitudinal tear of the posterior horn of the lateral meniscus (30 % of all meniscus injuries) and the second most common tear was a root detachment of the anterior horn of the lateral meniscus (20 % of all meniscus injuries). Higher age, advanced Tanner stage, and pubescence were significantly associated with an accompanying meniscal injury.

CONCLUSION

Meniscal injuries in children and adolescents undergoing surgical treatment for tibial eminence fractures must be expected in almost 40 %, with a higher prevalence with increasing age and sexual maturity. With regard to the clinical relevance, the results of the present study argue in favor for magnetic resonance imaging prior to surgery in every patient with a suspected tibial eminence fracture and for an arthroscopic approach to adequately diagnose and treat meniscal injuries.

LEVEL OF EVIDENCE

II.

Diagnosis and Treatment of Discoid Meniscus

There is a greater incidence of discoid meniscus in Asian countries than in Western countries, and bilateral discoid menisci are also common. The discoid meniscus may be a congenital anomaly, and genetics or family history may play a role in the development of discoid menisci. Because the histology of discoid meniscus is different from that of normal meniscus, it is prone to tearing. Individuals with a discoid meniscus can be asymptomatic or symptomatic. Asymptomatic discoid menisci do not require treatment. However, operative treatment is necessary if there are symptoms. Total meniscectomy leads to an increased risk of osteoarthritis. Therefore, total meniscectomy is generally reserved for rare unsalvageable cases. Partial meniscectomy (saucerization) with preservation of a stable peripheral rim combined with or without peripheral repair is effective, and good short-, mid-, and long-term clinical results have been reported.

Pediatric Knee Osteochondritis Dissecans Lesions

Osteochondritis dissecans (OCD) can cause knee pain and dysfunction in children. The etiology of OCD remains unclear; theories on causes include inflammation, ischemia, ossification abnormalities, genetic factors, and repetitive microtrauma. Most OCD lesions in skeletally immature patients will heal with nonoperative treatment. The success of nonoperative treatment decreases once patients reach skeletal maturity. The goals of surgical treatment include maintenance of articular cartilage congruity, rigid fixation of unstable fragments, and repair of osteochondral defects with cells or tissues that can adequately replace lost or deficient cartilage. Unsalvageable OCD lesions can be treated with various surgical techniques.

Discoid Meniscus Associated With Achondroplasia

Achondroplasia is the most common skeletal dysplasia. This form of dwarfism is caused by a point mutation in the fibroblast growth factor receptor 3 (FGFR3) gene, leading to inhibition of endochondral ossification for these patients. This results in a normal trunk height but shortened limbs. The discoid meniscus may be an important associated finding to better understand the common complaints of leg pain for these patients. Although the incidence for a discoid meniscus is between 3% and 5% for the general population, it is unknown with achondroplasia. This case series includes 4 patients, with ages ranging from adolescence to early adulthood, with symptoms of knee pain that were not attributable to some of the more common findings seen in this patient population. Typically, patients with achondroplasia who experience knee pain are evaluated for more common and well-known etiologies such as genu varum, ligamentous instability, and neurogenic claudication. However, the authors propose that symptomatic discoid lateral meniscus should be added to the differential diagnosis for lower-extremity pain in the achondroplasia population. A thorough history and physical examination, in combination with magnetic resonance imaging, can aid in making the diagnosis. Treatment with arthroscopic debridement, saucerization of the meniscus, and repair for unstable injuries has yielded good outcomes for this patient population. [Orthopedics. 2016; 39(3):e498-e503.].

Discrepancy between morphological findings in juvenile osteochondritis dissecans (OCD): a comparison of magnetic resonance imaging (MRI) and arthroscopy

PURPOSE

The aim of this study was to assess the reliability of preoperative MRI for the staging of osteochondritis dissecans (OCD) lesions of the knee and the talus in juvenile patients, using arthroscopy as the gold standard of diagnosis.

METHODS

Sixty-three juvenile patients (range 8-16 years) with an OCD of the knee or the talus underwent arthroscopy after MRI. In 54/9 out of 63 cases, 1.5/3 T MR scanners were used. The OCD stage was classified according the staging criteria of Dipaola et al. Arthroscopic findings were compared with MRI reports in each patient.

RESULTS

From the 63 juvenile patients, MRI/arthroscopy revealed a stage I OCD in 4/19 patients, stage II in 31/22 patients, stage III in 22/9 patients and stage IV in 6/6 patients. No osteochondral pathology was evident in arthroscopy in seven out of 63 patients. The overall accuracy of preoperative MRI in staging an OCD lesion of the knee or the talus was 41.3%. In 33 out of 63 patients (52.4%), arthroscopy revealed a lower OCD stage than in the preoperative MRI grading, and in four out of 63 cases (6.4%), the intraoperative arthroscopic grading was worse than in preoperative MRI prior to surgery. The utilization of the 3 T MRI provided a correct diagnosis with 44.4%.

CONCLUSIONS

Even with today's modern MRI scanners, it is not possible to predict an accurate OCD stage in children. The children's orthopaedist should not solely rely on the MRI when it comes to the decision to further conservative or surgical treatment of a juvenile OCD, but rather should take surgical therapy in consideration within persisting symptoms despite a low OCD stage provided by MRI.

LEVEL OF EVIDENCE

III.

Is posterior tibial slope associated with noncontact anterior cruciate ligament injury?

PURPOSE

This study aimed to: (1) examine whether the association between posterior tibial slope and noncontact ACL injury exists in Chinese population; (2) compare the reliability and consistency of the three methods (longitudinal axis, posterior and anterior tibial cortex axis) in lateral radiograph.

METHODS

Case-control study contained 146 patients in total (73 noncontact ACL injuries and 73 meniscus injuries, matched for age and gender), which were verified by arthroscopy, MRI and physical examination.

RESULTS

For the total population and the male subgroup, the mean posterior tibial slope of the ACL-injured group was significantly higher than that of the control group (P < 0.001). In addition, the longitudinal axis method exhibited the highest inter-rater (0.898) and intrarater reliability (0.928), whereas the anterior tibial cortex was the most variable (inter-rater reliability, 0.805; intrarater reliability, 0.824). The anterior tibial cortex method produced largest posterior tibial slope measurements (13.8 ± 3.3 for injury group; 11.6 ± 2.7 for control group), while the posterior tibial cortex method was the smallest (9.1 ± 3.1 for injury group; 7.2 ± 2.6 for control group). All three methods were not affected by age, sex, height, weight and BMI (n.s.).

CONCLUSIONS

The results of this study suggested that an increased posterior tibial slope was associated with the risk of noncontact ACL injury in Chinese population. Meanwhile, the longitudinal axis method is recommended for measuring posterior tibial slope in lateral radiograph in future studies. Posterior tibial slope measured by longitudinal axis method may be used as predictor of ACL injury.

LEVEL OF EVIDENCE

Case-control study, Level III.

Risk factors for noncontact anterior cruciate ligament injury: Analysis of parameters in proximal tibia using anteroposterior radiography

Objective

To investigate the relationship between the proximal tibial parameters of tibia width (TW), eminence width (EW), and eminence width index (EWI), and noncontact anterior cruciate ligament (ACL) injury, in a Chinese population.

Methods

A retrospective case–control study was conducted of all ACL reconstructions (ACL group) and meniscal surgeries (control group) undertaken at two Chinese hospitals. Patients in the ACL group were age- and sex-matched with controls. Anteroposterior knee radiographs were used to measure the TW, EW and EWI.

Results

A total of 73 pairs of patients who were verified by knee arthroscopy, magnetic resonance imaging and physical examination were included in the study. There was no significant difference between the ACL group and the control group in terms of TW in the total population and in the two sex subgroups. The ACL group had a significantly smaller EW and EWI compared with the control group in the total population and in the two sex subgroups.

Conclusion

Decreased EW and EWI are associated with increased risk of noncontact ACL injury in a Chinese population.

MR imaging-based diagnosis and classification of meniscal tears

Magnetic resonance (MR) imaging is currently the modality of choice for detecting meniscal injuries and planning subsequent treatment. A thorough understanding of the imaging protocols, normal meniscal anatomy, surrounding anatomic structures, and anatomic variants and pitfalls is critical to ensure diagnostic accuracy and prevent unnecessary surgery. High-spatial-resolution imaging of the meniscus can be performed using fast spin-echo and three-dimensional MR imaging sequences. Normal anatomic structures that can mimic a tear include the meniscal ligament, meniscofemoral ligaments, popliteomeniscal fascicles, and meniscomeniscal ligament. Anatomic variants and pitfalls that can mimic a tear include discoid meniscus, meniscal flounce, a meniscal ossicle, and chondrocalcinosis. When a meniscal tear is identified, accurate description and classification of the tear pattern can guide the referring clinician in patient education and surgical planning. For example, longitudinal tears are often amenable to repair, whereas horizontal and radial tears may require partial meniscectomy. Tear patterns include horizontal, longitudinal, radial, root, complex, displaced, and bucket-handle tears. Occasionally, meniscal tears can be difficult to detect at imaging; however, secondary indirect signs, such as a parameniscal cyst, meniscal extrusion, or linear subchondral bone marrow edema, should increase the radiologist's suspicion for an underlying tear. Awareness of common diagnostic errors can ensure accurate diagnosis of meniscal tears. Online supplemental material is available for this article.

Discoid Meniscus: Diagnosis and Management

Discoid lateral meniscus is a common abnormal meniscal variant in children. Detailed history and physical examination combined with an MRI of the knee predictably diagnose a discoid meniscus. The clinical presentation varies from being asymptomatic to snapping, locking, and causing severe pain and swelling of the knee. Because of the pathologic anatomy and instability, discoid menisci are more prone to tearing. Treatment options for symptomatic patients vary based on the type of anomaly, the age of the patient, stability, and the presence or absence of a tear. Improvements in arthroscopic equipment and technique have resulted in good to excellent short-term outcomes for saucerization and repair.

Clinical Evaluation and Preoperative Planning of Articular Cartilage Lesions of the Knee

Articular cartilage injuries are quite common. Most studies and review articles on cartilage repair and restoration focus on the different techniques available to treat cartilage defects; however, few thoroughly discuss the initial evaluation of patients with these defects. Outcomes are intimately associated with appropriate patient selection and indications for treatment; therefore, understanding the initial evaluation and conservative treatment of cartilage defects is essential to achieving excellent outcomes after surgical intervention, regardless of the chosen procedure. In patients with cartilage injury, a careful history, physical examination, and imaging are required before treating the lesion to ensure the patient's symptoms are actually related to the defect. To address any special considerations, other factors must be considered to improve patient outcomes, including the status of the meniscus, assessing and treating malalignment or off-loading the patellofemoral compartment, and reconstructing any ligamentous deficiencies. It is important for medical providers to understand what cartilage lesions may be symptomatic and when to refer these patients to surgeons who manage cartilage injury.

Diagnostic value of medical history and physical examination of anterior cruciate ligament injury: comparison between primary care physician and orthopaedic surgeon

PURPOSE

Well-designed validity studies on the clinical diagnosis of anterior cruciate ligament (ACL) injury are scarce. Our purpose is to assess the diagnostic value of ACL-specific medical history assessment and physical examination between primary and secondary care medical specialists.

METHODS

Medical history assessment and physical examination were performed by both an orthopaedic surgeon and a primary care physician, both blinded to all clinical information, in a secondary care population. A knee arthroscopy was used as reference standard. A total of 60 participants were divided into an index group with an arthroscopically proven complete ACL rupture and a control group with an arthroscopically proven intact ACL.

RESULTS

The orthopaedic surgeon recognized 94 % of the participants with an ACL rupture through a positive medical history combined with a positive physical examination; of the participants with an intact ACL, 16 % were misclassified by the orthopaedic surgeon. The primary care physician recognized 62 % of the participants with an ACL rupture and misclassified 23 % of the participants with an intact ACL. Physical examination appeared to have no additional value for the primary care physician.

CONCLUSIONS

Combined medical history and physical examination have strong diagnostic value in ACL rupture diagnostics performed by an orthopaedic surgeon, whereas for the primary care physician, only medical history appeared to be of value. For current practice, this could mean that only orthopaedic surgeons can perform an ACL physical examination with accuracy.

LEVEL OF EVIDENCE

III.

Diagnostic performance of magnetic resonance imaging and pre-surgical evaluation in the assessment of traumatic intra-articular knee disorders in children and adolescents: what conditions still pose diagnostic challenges?

BACKGROUND

Diagnosis of intra-articular lesions in children based on clinical examination and MRI is particularly challenging.

OBJECTIVE

To evaluate the diagnostic performance of MRI and pre-surgical evaluation of the knee in pediatric patients relative to arthroscopic evaluation as the gold standard. We report diagnoses frequently missed or inaccurately diagnosed pre-operatively.

MATERIALS AND METHODS

We conducted a retrospective review of MRI and pre-surgical evaluation in children and adolescents ages 1-17 years who were treated by knee arthroscopy during a 2½-year period. All MRIs were reviewed by a pediatric radiologist blinded to clinical findings. Pediatric orthopedic clinic notes were reviewed for pre-surgical evaluation (based on physical exam, radiograph, MR images and radiologist's MRI report). Arthroscopic findings were used as the gold standard. We calculated the percentages of diagnoses at arthroscopy missed on both MRI and pre-surgical evaluation. Diagnostic accuracy between children and adolescents and in patients with one pathological lesion vs. those with >1 lesion was analyzed. We performed a second review of MR images of the missed or over-called MRI diagnoses with knowledge of arthroscopic findings.

RESULTS

We included 178 children and adolescents. The most common diagnoses missed on MRI or pre-surgical evaluation but found at arthroscopy were: discoid meniscus (8/30, or 26.7% of cases); lateral meniscal tears (15/80, or 18.8% of cases); intra-articular loose bodies (5/36, or 13.9% of cases), and osteochondral injuries (9/73, or 12.3% of cases). Overall diagnostic accuracy of MRI and pre-surgical evaluation was 92.7% and 95.3%, respectively. No significant difference in diagnostic accuracy between children and adolescents was observed. When multiple intra-articular lesions were present, lateral meniscal tears were more likely to be inaccurately diagnosed (missed or over-called) on both MRI (P = 0.009) and pre-surgical evaluation (P < 0.001).

CONCLUSION

Overall diagnostic accuracy of MRI and pre-surgical evaluation was quite high. The traumatic intra-articular knee lesions that still pose a diagnostic challenge for MRI and pre-surgical evaluation are lateral discoid meniscus, lateral meniscal tears, intra-articular loose bodies and osteochondral injuries. Special attention should be given to those diagnoses when evaluating a pediatric knee MRI. In children with multiple intra-articular injuries, there is significantly more inaccuracy in pre-arthroscopic diagnosis of lateral meniscal tears on both MRI and pre-surgical evaluation.