Accuracy of MRI in the diagnosis of meniscal tears in patients with chronic ACL tears

Quantitative evaluation of meniscus injury using synthetic magnetic resonance imaging

BACKGROUND

Magnetic resonance imaging (MRI) can diagnose meniscal lesions anatomically, while quantitative MRI can reflect the changes of meniscal histology and biochemical structure. Our study aims to explore the association between the measurement values obtained from synthetic magnetic resonance imaging (SyMRI) and Stoller grades. Additionally, we aim to assess the diagnostic accuracy of SyMRI in determining the extent of meniscus injury. This potential accuracy could contribute to minimizing unnecessary invasive examinations and providing guidance for clinical treatment.

METHODS

Total of 60 (n=60) patients requiring knee arthroscopic surgery and 20 (n=20) healthy subjects were collected from July 2022 to November 2022. All subjects underwent conventional MRI and SyMRI. Manual measurements of the T1, T2 and proton density (PD) values were conducted for both normal menisci and the most severely affected position of injured menisci. These measurements corresponded to the Stoller grade of meniscus injuries observed in the conventional MRI. All patients and healthy subjects were divided into normal group, degeneration group and torn group according to the Stoller grade on conventional MRI. One-way analysis of variance (ANOVA) was employed to compare the T1, T2 and PD values of the meniscus among 3 groups. The accuracy of SyMRI in diagnosing meniscus injury was assessed by comparing the findings with arthroscopic observations. The diagnostic efficiency of meniscus degeneration and tear between conventional MRI and SyMRI were analyzed using McNemar test. Furthermore, a receiver operating characteristic curve (ROC curve) was constructed and the area under the curve (AUC) was utilized for evaluation.

RESULTS

According to the measurements of SyMRI, there was no statistical difference of T1 value or PD value measured by SyMRI among the normal group, degeneration group and torn group, while the difference of T2 value was statistically significant among 3 groups (P=0.001). The arthroscopic findings showed that 11 patients were meniscal degeneration and 49 patients were meniscal tears. The arthroscopic findings were used as the gold standard, and the difference of T1 and PD values among the 3 groups was not statistically significant, while the difference of T2 values (32.81±2.51 of normal group, 44.85±3.98 of degeneration group and 54.42±3.82 of torn group) was statistically significant (P=0.001). When the threshold of T2 value was 51.67 (ms), the maximum Yoden index was 0.787 and the AUC value was 0.934.

CONCLUSIONS

The measurement values derived from SyMRI could reflect the Stoller grade, illustrating that SyMRI has good consistency with conventional MRI. Moreover, the notable consistency observed between SyMRI and arthroscopy suggests a potential role for SyMRI in guiding clinical diagnoses.

Meniscal Ramp Lesion Repair Without the Need for a Posteromedial Portal

Medial meniscal ramp injury has gained the attention of orthopaedic surgeons in recent years. It consists of a tear of the peripheral insertion of the posterior horn of the medial meniscus. Its prevalence in anterior cruciate ligament reconstruction varies between 9% and 40% according to different studies. Ramp lesions cannot always be diagnosed using magnetic resonance imaging scans. To identify ramp lesions, the arthroscope should be introduced into the posteromedial compartment of the knee during the routine examination of the knee (Gillquist maneuver). Not all authors advocate systematically repairing ramp injuries of the medial meniscus, especially when these injuries are small and stable. They have historically been repaired using an outside-in technique using a hook-type suture passed through a posteromedial portal. In this study, we present our all-inside suture technique without the use of a posteromedial portal.

Automated Radiology-Arthroscopy Correlation of Knee Meniscal Tears Using Natural Language Processing Algorithms

RATIONALE AND OBJECTIVES

Train and apply natural language processing (NLP) algorithms for automated radiology-arthroscopy correlation of meniscal tears.

MATERIALS AND METHODS

In this retrospective single-institution study, we trained supervised machine learning models (logistic regression, support vector machine, and random forest) to detect medial or lateral meniscus tears on free-text MRI reports. We trained and evaluated model performances with cross-validation using 3593 manually annotated knee MRI reports. To assess radiology-arthroscopy correlation, we then randomly partitioned this dataset 80:20 for training and testing, where 108 test set MRIs were followed by knee arthroscopy within 1 year. These free-text arthroscopy reports were also manually annotated. The NLP algorithms trained on the knee MRI training dataset were then evaluated on the MRI and arthroscopy report test datasets. We assessed radiology-arthroscopy agreement using the ensembled NLP-extracted findings versus manually annotated findings.

RESULTS

The NLP models showed high cross-validation performance for meniscal tear detection on knee MRI reports (medial meniscus F1 scores 0.93-0.94, lateral meniscus F1 scores 0.86-0.88). When these algorithms were evaluated on arthroscopy reports, despite never training on arthroscopy reports, performance was similar, though higher with model ensembling (medial meniscus F1 score 0.97, lateral meniscus F1 score 0.99). However, ensembling did not improve performance on knee MRI reports. In the radiology-arthroscopy test set, the ensembled NLP models were able to detect mismatches between MRI and arthroscopy reports with sensitivity 79% and specificity 87%.

CONCLUSION

Radiology-arthroscopy correlation can be automated for knee meniscal tears using NLP algorithms, which shows promise for education and quality improvement.

Rates of Concomitant Meniscal Tears in Pediatric Patients With Anterior Cruciate Ligament Injuries Increase With Age and Body Mass Index

Background

Anterior cruciate ligament (ACL) tears are frequently associated with meniscal injury. Risk factors for concomitant meniscal injuries have been studied in the adult population but less so in pediatric patients.

Purpose

To evaluate the relationship between age and body mass index (BMI) and the presence of a concomitant meniscal tear at the time of ACL reconstruction (ACLR) in pediatric patients.

Study Design

Case-control study; Level of evidence, 3.

Methods

A single-institution retrospective review was performed of patients aged <19 years who underwent primary ACLR over a 3.5-year period. Revision ACLR and multiligament knee reconstructions were excluded. Logistic regression was used to identify risk factors associated with having a meniscal tear at the time of surgery. Subgroup analysis was performed for medial and lateral meniscal tears.

Results

Included in this study were 453 patients (230 males, 223 females; median age, 15 years). Of these, 265 patients (58%) had a meniscal tear, including 150 isolated lateral meniscal tears, 53 isolated medial meniscal tears, and 62 patients with both lateral and medial meniscal tears. Median time from injury to surgery was 48 days. For every 1-year increase in age, there was a 16% increase in the adjusted odds of having any meniscal tear (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.05-1.27; P = .002), with a 20% increase in the odds of having a medial meniscal tear (OR, 1.20; 95% CI, 1.07-1.35; P = .002) and a 16% increase in the odds of having a lateral meniscal tear (OR, 1.16; 95% CI, 1.05-1.27; P = .003). For every 2-point increase in BMI, there was a 12% increase in the odds of having any meniscal tear (OR, 1.12; 95% CI, 1.02-1.22; P = .016) and a 10% increase in the odds of having a lateral meniscal tear (OR, 1.10; 95% CI, 1.01-1.19; P = .028).

Conclusion

Pediatric patients undergoing ACLR had a 58% incidence of concomitant meniscal pathology. Increasing age and BMI were independent risk factors for these injuries, while no association was found between time to surgery and meniscal pathology.

Diagnostic Accuracy of Magnetic Resonance Imaging in the Detection of Type and Location of Meniscus Tears: Comparison with Arthroscopic Findings

Magnetic resonance imaging (MRI) has been widely used for the diagnosis of meniscal tears, but its diagnostic accuracy, depending on the type and location, has not been well investigated. We aimed to evaluate the diagnostic accuracy of MRI by comparing MRI and arthroscopic findings. Preoperative 3.0-T MRI and arthroscopic findings from 2005 to 2018 were reviewed to determine the presence, type, and location of meniscus tears. In addition, subgroup analysis was performed according to anterior cruciate ligament (ACL) injury. The exclusion criteria were as follows: (1) Inflammatory arthritis, (2) other ligament injuries, (3) inability to classify meniscal tears due to degenerative arthritis, (4) over 90 days from MRI to surgery, and (5) incomplete data. Of the 2998 eligible patients, 544 were finally included. The sensitivity and specificity of MRI in determining medial and lateral meniscus tears were 91.8% and 79.9%, and 80.8% and 85.4%, respectively. The accuracy of MRI in the ACL-injured group was lower than that in the ACL-intact group (medial meniscus: 81.7% vs. 88.1%, p = 0.041; 72.9% vs. lateral meniscus: 88.0%, p < 0.001). MRI accuracy was low for the longitudinal tears of the posterior horn of the medial meniscus in the ACL-injured group. MRI could be a diagnostic tool for meniscus tears, but has limited accuracy in their classification of the type and location. Hence, care should be taken during arthroscopic assessment of ACL-injured patients due to low diagnostic accuracy of preoperative MRI.

Sonographic soft tissue arthritic changes associated with post-stroke hemiplegic knee pain: utility of musculoskeletal ultrasound in a resource-limited setting

Purpose

Post-stroke arthritic changes that may compromise rehabilitation have been described in the upper and lower limbs. We aimed at evaluating the soft tissue arthritic changes associated with pain in hemiplegic knees of stroke patients in our environment.

Material and methods

Hemiplegic and non-hemiplegic knees of 48 stroke patients as well as both knees of 26 apparently healthy controls were evaluated with a 7.5-12 MHz linear ultrasound probe. History of knee pain, and socio-demographic, laboratory, and clinical data were recorded for all study participants. Muscle tone and power as well as functional ambulatory category (FAC) were graded for the stroke patients. Data was analysed using SPSS version 20.

Results

Pain was reported more often in hemiplegic than non-hemiplegic knees (n = 16 vs. n = 6, p = 0.021). The frequencies of soft tissue arthritic changes found, which included reduced lateral and medial femoral cartilage thickness, suprapatellar effusion, and irregular cartilage-bone margin, were similar between hemiplegic and non-hemiplegic knees (p > 0.05). Suprapatellar effusion and reduced lateral femoral cartilage thickness were more prevalent in the hemiplegic knees compared to the healthy control knees (p < 0.05). Stroke patients with pes anserinus tendinosis had greater risk of hemiplegic knee pain (HKP) when compared to stroke patients without this lesion (OR = 10; 95% CI: 1.7-61). FAC, muscle tone, and power showed no association with HKP.

Conclusions

Soft tissue arthritic changes associated with knee pain are comparable between hemiplegic and non-hemiplegic knees of stroke patients. The risk of knee pain in stroke is higher in the presence of pes anserinus tendinosis.

Confirming the Presence of Unrecognized Meniscal Injuries on Magnetic Resonance Imaging in Pediatric and Adolescent Patients With Anterior Cruciate Ligament Tears

BACKGROUND

Prior research has shown decreased accuracy of meniscal injury detection using magnetic resonance imaging (MRI) for anterior cruciate ligament (ACL)-deficient adult patients as well as ACL-deficient pediatric and adolescent patients. The objectives of this study were the following: (1) assess the diagnostic ability of MRI in detecting meniscal injuries for pediatric and adolescent patients undergoing arthroscopic ACL reconstruction and (2) characterize the unrecognized meniscal injuries.

METHODS

The sensitivity, specificity, positive predictive value, and negative predictive value of meniscal tears (medial, lateral, or both) on MRI were calculated for the 107 patients in this cohort. Fisher exact tests were used to compare event frequencies between medial meniscal (MM) and lateral meniscal (LM) tears. One-way analysis of variance tests were performed to compare event rates between the location and type of unrecognized meniscal tears.

RESULTS

The median age of the cohort was 15 (range: 7 to 18). The sensitivity, specificity, positive predictive value, and negative predictive value of MRI in detecting meniscal tears (medial, lateral, or both) in ACL-deficient pediatric and adolescent patients was 62.3%, 68.4%, 78.2%, and 50.0%, respectively. There were 26 (24.3%) cases in which a meniscal injury was not detected on MRI, but was discovered arthroscopically (MM: 5 knees, LM: 20 knees, both: 1 knee). These unrecognized meniscal injuries were more commonly the LM than the MM (77.8%, P-value=0.100), a vertical/longitudinal tear type (77.8%, P-value <0.001), and located in the posterior horn (74.1%, P-value <0.001).

CONCLUSIONS

In this ACL-deficient pediatric and adolescent cohort, there were 26 (24.3%) patients with unrecognized meniscal injuries. A vertical tear in the posterior horn was the most commonly unrecognized meniscal injury, supporting the findings of prior research postulating that the location and configuration of a tear influence the accuracy of MRI in detecting these injuries. More research is needed to investigate strategies to improve the detection of meniscal tears in pediatric and adolescent patients preoperatively. These findings have implications with regard to patient counseling, operative planning, anticipatory guidance with regard to postoperative rehabilitation, recovery expectations, and surgical outcomes.

LEVEL OF EVIDENCE

Level IV.

Single Intravenous Administration of Tranexamic Acid in Anterior Cruciate Ligament Reconstruction to Reduce Postoperative Hemarthrosis and Increase Functional Outcomes in the Early Phase of Postoperative Rehabilitation: A Randomized Controlled Trial

PURPOSE

To evaluate the effect of tranexamic acid (TXA) in patients undergoing anterior cruciate ligament (ACL) reconstruction in reducing intra-articular effusion and affecting clinical outcomes 3 months after surgery.

METHODS

Eighty consecutive patients undergoing ACL reconstruction were prospectively assessed from 2014 to 2016. Patients were randomly allocated to 1 of 2 groups: The test group received an intravenous infusion of 15 mg/kg of TXA, and the control group did not receive TXA. The patellar circumference, range of motion (ROM), Coupens and Yates (CY) value, visual analog scale score for pain assessment, and quadriceps strength (QS) were considered on postoperative day (PD) 1, PD 7, and PD 15 and at 1 month and 3 months after surgery. Blood volume in the intra-articular drainage was recorded on PD 1. Any adverse effect, such as fever onset (>37.5°C), hemarthrosis, or infection, was also considered.

RESULTS

We found a statistically significant reduction in drainage blood volume (P < .001) and CY value (P = .0044) on PD 1 in patients in the test group compared with those in the control group. On PD 7, a significant improvement was found for mean CY values (P = .0057), ROM (P = .0031), and QS (P = .015). On PD 15, we noted significant improvements in CY values (P < .001), patellar circumference (P = .0019), QS (P = .0089), and visual analog scale values (P = .0032) in the test group. We noted 13 fever episodes in the control group and 2 fever episodes in the study group (P = .047). No differences for any outcomes or complications were found at 3 months.

CONCLUSION

TXA administration reduced hemarthrosis and the amount of suction drainage blood volume, improved ROM and QS, and reduced fever episodes during the first 2 weeks after surgery. TXA use improved early-phase outcomes in the postoperative period after ACL reconstruction.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

3D-MRI combined with signal-to-noise ratio measurement can improve the diagnostic accuracy and sensitivity in evaluating meniscal healing status after meniscal repair

PURPOSE

This study compared the diagnostic accuracy of second-look arthroscopy, clinical assessment, and magnetic resonance imaging (MRI) in evaluating meniscal healing following repair. To explore the application of 3D-MRI sequences with signal-to-noise ratio (SNR) measurements and the analysis of sensitivity and accuracy in evaluating meniscal healing status after meniscal repair.

METHODS

This study included 75 patients (75 menisci; mean age, 25.4 ± 6.6 years) who underwent arthroscopic meniscal repair (medial menisci, 45; and lateral menisci, 29). Follow-up evaluation included clinical assessment, magnetic resonance imaging (MRI), and second-look arthroscopy (mean follow-up, 10.2 ± 3.4 months). The criteria defined for unhealed menisci were: on arthroscopy, presence of cleft; on clinical assessment, presence of joint-line tenderness, swelling, locking, or positive McMurray test; on MRI, grade III signal intensity at the site of repair. Finally, the SNR on 3D-MRI of the healed and the unhealed groups were compared.

RESULTS

On second-look arthroscopy, 68 (90.7%) menisci were found to be completely healed. With the arthroscopic healing rate as the standard, the clinical healing rate was 69.3% (63 menisci) [sensitivity, 85.7%; specificity, 75.0%; accuracy, 76.0%; positive predictive value (PPV), 26.1%; negative predictive value (NPV), 98.1%]. Similarly, the sensitivity, specificity, accuracy, PPV and NPV, respectively, for MRI in four sequences were as follows: 2D-T2W-Sag: 71.4, 79.4, 78.7, 26.3, and 96.4%; 2D-T2W-Cor: 71.4, 82.4, 81.3, 29.4, and 96.6%; 3D-PDW-Sag: 100.0, 50.0, 54.7, 17.1, and 100.0%; 3D-PDW-Cor: 100.0, 58.8, 62.7, 20.0, and 100.0%. The mean SNRs of the healed group (3D-PDW-Sag, 66.7 ± 11.9; 3D-PDW-Cor, 63.9 ± 12.4) were significantly lesser than that of the unhealed group (3D-PDW-Sag, 89.2 ± 9.6; 3D-PDW-Cor, 82.2 ± 18.5) (P < 0.05). Identifying grade 3 meniscal damage on 3D-PDW images prior to applying the different SNR cut-off points revealed SNR values 80 in the sagittal plane and 70 in the coronal plane as having better diagnostic accuracy and sensitivity. The clinical relevance of the study was that 3D-MRI combined with SNR measurement may be a noninvasive and accurate method of assessment clinically, and a reliable alternative to second-look arthroscopy.

LEVEL OF EVIDENCE

III.

A Prospective, Blinded, Multicenter Clinical Trial to Compare the Efficacy, Accuracy, and Safety of In-Office Diagnostic Arthroscopy With Magnetic Resonance Imaging and Surgical Diagnostic Arthroscopy

PURPOSE

The purpose of this study was to compare the efficacy, accuracy, and safety of in-office diagnostic arthroscopy with magnetic resonance imaging (MRI) and surgical diagnostic arthroscopy.

METHODS

A prospective, blinded, multicenter, clinical trial was performed on 110 patients, ages 18 to 75 years, who presented with knee pain. The study period was April 2012 to April 2013. Each patient underwent a physical examination, an MRI, in-office diagnostic imaging, and a diagnostic arthroscopic examination in the operating room. The attending physician completed clinical report forms comparing the in-office arthroscopic examination and surgical diagnostic arthroscopy findings on each patient. Two blinded experts, unaffiliated with the clinical care of the study's subjects, reviewed the in-office arthroscopic images and MRI images using the surgical diagnostic arthroscopy images as the "control" group comparison. Patients were consecutive, and no patients were excluded from the study.

RESULTS

In this study, the accuracy, sensitivity, and specificity of in-office arthroscopy was equivalent to surgical diagnostic arthroscopy and more accurate than MRI. When comparing in-office arthroscopy with surgical diagnostic arthroscopy, all kappa statistics were between 0.766 and 0.902. For MRI compared with surgical diagnostic arthroscopy, kappa values ranged from a low of 0.130 (considered "slight" agreement) to a high of 0.535 (considered "moderate" agreement). The comparison of MRI to in-office arthroscopy showed very similar results as the comparison of MRI with surgical diagnostic arthroscopy, ranging from a low kappa of 0.112 (slight agreement) to a high of 0.546 (moderate agreement). There were no patient-related or device-related complications related to the use of in-office arthroscopy.

CONCLUSIONS

Needle-based diagnostic imaging that can be used in the office setting is statistically equivalent to surgical diagnostic arthroscopy with regard to the diagnosis of intra-articular, nonligamentous knee joint pathology. In-office diagnostic imaging can provide a more detailed and accurate diagnostic assessment of intra-articular knee pathology than MRI. Based on the study results, in-office diagnostic imaging provides a safe, accurate, real-time, minimally invasive diagnostic modality to evaluate intra-articular pathology without the need for surgical diagnostic arthroscopy or high-cost imaging.

LEVEL OF EVIDENCE

Level II, comparative prospective trial.

Ramp lesions in ACL deficient knees in children and adolescent population: a high prevalence confirmed in intercondylar and posteromedial exploration

PURPOSE

Ramp lesions are common in ACL deficient knees. Their diagnosis is difficult and, therefore, they may be underestimated. So far, no study analyzed their prevalence in a pediatric population. The diagnosis of these Ramp lesions is of major clinical relevance because of a frequent misestimating and technic difficulties. Ramp lesions might be associated with residual knee pain and instability after ACL reconstruction. The aim of this study was to evaluate the prevalence of ramp lesions explored through a systematic intercondylar and posteromedial arthroscopic approach during an ACL reconstruction in a pediatric and adolescent population.

METHODS

Children and adolescents who underwent an ACL reconstruction were screened prospectively between October 2014 and 2016. The presence or absence of a ramp lesion was evaluated after each of three arthroscopic steps: (1) an anterior approach, (2) an intercondylar inspection, and (3) a posteromedial approach. Ramp lesions were screened at each step and their prevalence was evaluated. Furthermore, their presence was correlated to age, weight, size, sex, and state of the physis (open or closed). Finally, the meniscal status on MRI and arthroscopic findings were compared.

RESULTS

Fifty-six patients were analyzed. The median age was 14.0 ± 1.3 years (12-17). The median interval between injury and surgery was 11.5 months (1-108). During step 1 (anterior approach), only 1 ramp lesion (2%) was diagnosed. 13 (23%) ramp lesions were found after inspection through the intercondylar notch. No additional lesions were found with a direct view through the posteromedial approach. No correlation between ramp lesions and side, sex, weight, size, or state of physis was found. 10 ramp lesions out of 13 could not be diagnosed on MRI.

CONCLUSIONS

The prevalence of ACL-associated ramp lesions in children and adolescents is similar to adult populations. A systematic inspection through the intercondylar notch is recommended during ACL reconstruction to make a precise diagnosis. The posteromedial approach is essentially useful for meniscal repair LEVEL OF EVIDENCE: Testing, previously developed diagnostic criteria in a consecutive series of patients and a universally applied "gold" standard, Level I.

Use of MRI by radiologists and orthopaedic surgeons to detect intra-articular injuries of the knee

OBJECTIVE

Magnetic resonance imaging (MRI) is paramount in the assessment of knee pathology, particularly when planning for a surgical procedure. This study compared the diagnostic accuracy in MRI reading of pathological knees by radiologists and orthopaedic surgeons.

MATERIALS AND METHODS

Cross-sectional study comprising 80 randomly selected patients previously submitted to arthroscopic surgery after clinical examination and MRI. A diagnosis by MRI interpretation was requested from the two teams, one of radiologists and another of orthopaedic surgeons. The conclusions of each team were later compared. Statistical significance was considered for p < 0.05.

RESULTS

The radiologists' findings achieved statistical significance regarding osteochondral injuries, ACL, and medial meniscus (p < 0.05), and orthopaedic surgeons regarding ACL injuries and menisci (p < 0.05). ACL injuries demonstrated a statistically significant association between teams (p < 0.001).

CONCLUSIONS

MRI appears to offer reliable readings of ACL injuries, regardless the specialty of the observer. The lateral compartment is scarcely well read.

In-office arthroscopy for the evaluation of chronic knee pain: A case report

This is a case report detailing the use of in-office needle arthroscopy (mi-eye 2™) in a patient with chronic knee pain and inconclusive magnetic resonance imaging findings. The patient is a 40-year-old male who presented to our clinic after an extended history of right knee pain along the medial aspect with previous failed treatments. Magnetic resonance imaging without contrast had demonstrated full-thickness chondral fissuring of the lateral patellar facet, mild abnormal signals of the proximal patellar tendon and Hoffa’s fat pad, and intact anterior cruciate ligament and posterior cruciate ligament. The patient was previously treated with an ultrasound-guided injection of 2 cm³ of 1% lidocaine without epinephrine and 1 cm³ of Kenalog-40 and scheduled for follow-up. At follow-up, clinical examination showed antalgic gait, minimal tenderness along medial joint line, medial pain in deep flexion, and no pain when in varus or valgus. Due to continued discomfort with a negative magnetic resonance imaging, in-office diagnostic arthroscopy was performed using mi-eye 2 revealing a tear of the mid-body of the medial meniscus. The patient subsequently underwent arthroscopic repair and is recovering well with complete resolution of medial joint pain. This report highlights the clinical utility of in-office diagnostic arthroscopy in the management of patients with persistent knee pain and negative or equivocal findings on magnetic resonance imaging.

Reliability of magnetic resonance imaging in evaluating meniscal and cartilage injuries in anterior cruciate ligament-deficient knees

PURPOSE

The accuracy of magnetic resonance (MR) imaging in assessing meniscal and cartilage injuries in anterior cruciate ligament (ACL)-deficient knees as compared to arthroscopy was evaluated in the present study.

METHODS

The results of all preoperative MR imaging performed within 3 months prior to the ACL reconstruction were compared against intraoperative arthroscopic findings. A total of 206 patients were identified. The location and type of meniscal injuries as well as the location and grade of the cartilage injuries were studied. The negative predictive value, positive predictive value, sensitivity, specificity and accuracy of MR imaging for these 206 cases were calculated and analysed.

RESULTS

In patients with an ACL injury, the highest incidence of concomitant injury was that of medial meniscus tears, 124 (60.2 %), followed by lateral meniscus tears, 105 (51.0 %), and cartilage injuries, 66 (32.0 %). Twenty-three (11.2 %) patients sustained injuries to all of the previously named structures. MR imaging was most accurate in detecting medial meniscus tears (85.9 %). MR imaging for medial meniscus tears also had the highest sensitivity (88.0 %) and positive predictive value (88.7 %), while MR imaging for cartilage injuries had the largest specificity (84.1 %) and negative predictive value (87.1 %). It was least accurate in evaluating lateral meniscus tears (74.3 %). The diagnostic accuracy of medial meniscus imaging is significantly influenced by age and the presence of lateral meniscus tears, while the duration between MR imaging and surgery has greater impact on the likelihood of lateral meniscus and cartilage injuries actually being present during surgery. The majority of meniscus tears missed by MR imaging affected the posterior horn and were complex in nature. Cartilage injuries affecting the medial femoral condyle or medial patella facet were also often missed by MR imaging.

CONCLUSION

MR imaging remains a reliable tool for assessing meniscus tears and cartilage defects preoperatively. It is most accurate when evaluating medial meniscus tears. However, MR imaging should be used with discretion especially if there is a high index of suspicion of lateral meniscus tears.

LEVEL OF EVIDENCE

IV.

Cartilage Delamination Flap Mimicking a Torn Medial Meniscus

We report a case of a chondral delamination lesion due to medial parapatellar plica friction syndrome involving the medial femoral condyle. This mimicked a torn medial meniscus in clinical and radiological presentation. Arthroscopy revealed a chondral delamination flap, which was debrided. Diagnosis of chondral lesions in the knee can be challenging. Clinical examination and MRI have good accuracy for diagnosis and should be used in tandem. Early diagnosis and treatment of chondral lesions are important to prevent progression to early osteoarthritis.

Comparison of clinical, MRI and arthroscopic assessments of chronic ACL injuries, meniscal tears and cartilage defects

PURPOSE

The aim of this study was to compare the accuracy of clinical examination to that of MRI evaluated by two independent radiologists for the diagnosis of meniscal tears and chronic anterior cruciate ligament injuries and to assess the MRI accuracy in the diagnosis of cartilage defects.

METHODS

Seventy-six consecutive patients with suspected intra-articular knee pathology were prospectively evaluated by objective examination, 1.5 T MRI, re-examined by trained radiologist and arthroscopy. Accuracy, sensitivity, specificity, positive predictive value and negative predictive value were calculated. Agreement analysis with kappa (К) coefficient values was performed for meniscal and ACL tears.

RESULTS

No differences were found between diagnostic accuracy of clinical examination, the first and second MRI reports in diagnosis of medial meniscus (84 vs 96 vs 97 %) and anterior cruciate ligament injuries (93 vs 78 vs 89 %). For the lateral meniscal tears, the accuracy of the second radiologist was significantly higher than those of the first (96 vs 75 %; p < 0.01) and clinical examination (96 vs 86 %; p = 0.02). High diagnostic values were obtained for the diagnosis of full-thickness chondral defects with sensitivity of 100 %, specificity of 95 % and accuracy of 95 %.

CONCLUSION

Clinical and MRI evaluations have no differences in the diagnosis of medial meniscus and anterior cruciate ligament injuries. A trained radiologist obtained better sensitivity, specificity and accuracy in the diagnosis of lateral meniscus. 1.5 T MRI does not represent the technique of choice in the evaluation of chondral defect but demonstrated high diagnostic accuracy for detection of full-thickness chondral defects.

LEVEL OF EVIDENCE

Diagnostic prospective study, Level II.

The anterolateral ligament in a Japanese population: Study on prevalence and morphology

BACKGROUND

The anterolateral ligament of the knee (ALL) has been attracting research attention as the ligament related to the Segond fracture. In this study, we investigated the prevalence and morphological variation of the ALL and developed a classification for the ALL in Japanese people.

METHODS

A total of 94 knees of 54 room cadavers of Japanese people were examined (24 male, 30 female; age range 70-103 years; average age: 85.6 years). Knees with damaged ligaments, such as ACL rupture, and with bony abnormalities were excluded. The ALL-like structure was classified based on orientation and shape of the structures.

RESULTS

The fibrous structure independent from the knee joint capsule in the anterolateral part of the knee was present in 35 knees out of 94 knees (37.2%). This structure was classified into two types, based on thickness: type I is for the strong ligamentous structures of more than 1 mm in thickness; and type II is for weak aponeurotic structures of equal or less than 1 mm thickness. Here we regard the anterolateral ligament (ALL) as the type I and the type II is termed anterolateral ligamentous tissue (ALLT). Type I was seen in 19 of 35 knees (54.3%), and type II was seen in 16 of 35 knees (45.7%).

CONCLUSIONS

This study described the fibrous structure of the anterolateral portion of the knee, and classified the ligamentous structure into type I (ALL) and thin aponeurotic type II (ALLT). The prevalence of the ALL in Japanese people was approximately 20% and was significantly lower than in previous studies, which were reported values from 50% to 100%.

Accuracy of MRI evaluation of meniscus tears in the setting of ACL injuries

BACKGROUND

Our purpose was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) for the pre-operative detection of meniscus tears requiring operative intervention, and identify factors that determined accuracy of diagnosing meniscus tears, in the setting of anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients who underwent primary ACL reconstruction were retrospectively reviewed. A meniscus tear was classified as requiring treatment if it was debrided or repaired at the time of ACL reconstruction. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of pre-operative MRIs were determined for medial and lateral meniscus tears.

RESULTS

Sensitivity, specificity, PPV, and NPV of MRI were 0.90, 0.75, 0.58, and 0.95 for medial meniscus tears, respectively, and 0.67, 0.81, 0.65, and 0.82 for lateral meniscus tears. MRI-diagnosed medial meniscus tears were associated with a longer time interval between initial injury and imaging compared to ACL tears without concomitant meniscus injury on MRI (p=0.038). Vertical medial meniscus tears were less likely than other tear patterns to require treatment at the time of ACL reconstruction (p=0.03). MRI showed a higher diagnostic performance for lateral meniscus tears when surgery was performed within 30days of imaging.

CONCLUSIONS

This study demonstrates only moderate sensitivity and specificity of pre-operative MRI in the detection of meniscus tears requiring operative treatment in the setting of ACL injury. High rates of false diagnoses were observed, suggesting MRI may not be as accurate in predicting positive or negative meniscus findings at the time of ACL reconstruction as previously reported.

LEVEL OF EVIDENCE

Level III.

Risk Factors of False-Negative Magnetic Resonance Imaging Diagnosis for Meniscal Tear Associated With Anterior Cruciate Ligament Tear

PURPOSE

To identify risk factors that predict false-negative magnetic resonance imaging (MRI) diagnosis for meniscal tear coincident with anterior cruciate ligament injury using multivariate logistic regression.

METHODS

We reviewed the medical records of consecutive patients who underwent arthroscopic anterior cruciate ligament reconstruction from January 2006 through December 2014. Exclusion criteria were no meniscal tear or incomplete tear less than 10 mm in length, delay to surgery from initial injury more than 1 year, delay to surgery from preoperative MRI more than 4 weeks, revisions, fracture histories, and multiple ligament injuries. According to preoperative MRI diagnosis, the meniscal tears were sorted into true-positive MRI and false-negative MRI groups. Multivariate logistic regression was used to analyze risk factors including age, gender, body mass index, time from injury to MRI, knee instability, concomitant ligament injury, intra-articular effusion, bone contusion, cartilage injury, meniscal tear location, and meniscal tear pattern.

RESULTS

Enrolled 249 meniscal tears (159 medial and 90 lateral menisci) were sorted into true-positive MRI (n = 136) and false-negative MRI (n = 113) groups. As time from injury to MRI diagnosis increased, the risk of the false-negative MRI diagnosis decreased (adjusted odds ratio [OR], 0.859; 95% confidence interval [CI], 0.802-0.921). Meniscal tear location within the posterior one-third was a significant risk factor compared with tear within the anterior one-third (adjusted OR, 11.823; 95% CI, 2.272-61.519). Peripheral longitudinal tear pattern was also a significant risk factor (adjusted OR, 3.522; 95% CI, 1.256-9.878).

CONCLUSIONS

Significant risk factors for false-negative MRI included short time from injury to MRI diagnosis, meniscal tear location within the posterior one-third, and peripheral longitudinal tear pattern.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Knee instability scores for ACL reconstruction

Despite abundant biological, biomechanical, and clinical research, return to sport after anterior cruciate ligament (ACL) injury remains a significant challenge. Residual rotatory knee laxity has been identified as one of the factors responsible for poor functional outcome. To improve and standardize the assessment of knee instability, a variety of instability scoring systems is available. Recently, devices to objectively quantify static and dynamic clinical exams have been developed to complement traditional subjective grading systems. These devices enable an improved evaluation of knee instability and possible associated injuries. This additional information may promote the development of new treatment algorithms and allow for individualized treatment. In this review, the different subjective laxity scores as well as complementary objective measuring systems are discussed, along with an introduction of injury to an individualized treatment algorithm.

Current status of ACL reconstruction in Germany

INTRODUCTION

Reconstruction of the anterior cruciate ligament (ACL) is characterized by a variety of possibilities concerning its implementation. Different choices for grafts, fixation methods and tunnel positioning, as well as diverse technical tools are available and have clinical significance. Besides specific pre- and post-operative procedures, different indications for surgery and further surgeon-/clinic-related factors add variability to the treatment. In response to the lack of descriptive statistics about the implementation of these factors and the increasing numbers of ACL reconstructions this study has been conducted to display the current state of the treatment for ACL tears throughout Germany.

MATERIALS AND METHODS

709 clinics with surgical and orthopedic departments were provided an online-questionnaire that surveyed their statistical records (e.g. annually implemented operations, number of surgeons, duration of operations), implemented techniques (e.g. choice of grafts, construction of drilling tunnel, tibial/femoral fixation) and personal assessment (e.g. frequency/cause of graft failure, frequency/handling of infection). The response rate was 22 % (n = 155). Based on the statistical records a specialized group within the respondents was identified, enabling a cross-comparison between high- and low-volume surgeons.

RESULTS

On average, the German orthopedic surgeons in the clinics surveyed annually performs 35 ACL reconstructions, with each operation lasting an average of 67 min. After subdividing the data with references to annually performed surgeries into high- and low-volume-surgeons, differences and common features between the subgroups become apparent. Differences between high- and low-volume-surgeons, respectively, show shorter duration of both ACL reconstructions (55 vs. 71 min) and revision ACL reconstructions (75 vs. 90 min), higher membership rates in professional associations (83 vs. 38 % have at least one membership), more frequent implementation of stability examinations (47 vs. 21 %) and different frequencies of femoral drilling techniques (using the anterolateral portal in 71 vs. 54 %). With reference to evaluating operation dates, choosing grafts and assessing reasons for graft failure both groups share commonalities, as well as regarding the predominant use of monofixation for femoral fixation (88 % of the participants-mainly with endobutton in 38 % and transfixation pin in 27 %) and for tibial fixation (81 % of the participants-mainly with bioabsorbable screw in 60 %).

CONCLUSIONS

The treatment of ACL tears in the group of German clinics studied is characterized by a variety of surgical possibilities. This condition might reflect the entirety of clinics reconstructing ACL in Germany. For the first time, a descriptive statistical survey was implemented to display this variety and to provide insight into the current status quo. Within the entirety of surgeons implementing ACL reconstruction a specialized subgroup with a particular expertise seems to exist.

Diagnosis of ligamentous and meniscal pathologies in patients with anterior cruciate ligament injury: comparison of magnetic resonance imaging and arthroscopic findings

BACKGROUND

Magnetic resonance imaging (MRI) is routinely used to diagnose or support clinical diagnoses for meniscal or ligamentous injuries prior to offering patients arthroscopic treatment. However, the sensitivity of MRI for the detection of meniscal injury is not yet 100%. Sportsmen have occasionally returned to play with undiagnosed meniscal lesions on the basis of a normal MRI examination. This study was designed to assess the diagnostic parameters of MRI in patients with acute anterior cruciate ligament (ACL) injury.

METHODS

MRI and arthroscopic findings of 320 patients with acute ACL injury were included in this retrospective review. Patients belonged to a single surgeon from a high volume tertiary healthcare institution. All patients had either a MRI or an arthroscopic diagnosis of an acute ACL injury of one knee or both. All patients underwent therapeutic arthroscopy by the senior author routinely as part of arthroscopy-aided ACL reconstruction. Arthroscopic findings were the diagnostic reference based on which the positive predictive value (PPV), negative predictive value (NPV), sensitivity, specificity and concordance strength of association of MRI were calculated for ACL, posterior cruciate ligament (PCL), medial meniscus (MM) and lateral meniscus (LM) injuries.

RESULTS

MRI was most accurate in diagnosing cruciate ligament injuries with a PPV approaching 100%. The PPV of MRI in diagnosing meniscal injuries was approximately 60%. MRI was almost 100% sensitive and specific in diagnosing ACL injuries and 82% sensitive and 100% specific in diagnosing PCL injuries. Conversely, MRI was 77% sensitive and 90% specific in diagnosing MM injuries; and 57% sensitive and 95% specific in diagnosing LM injuries.

CONCLUSIONS

MRI remains the gold standard for diagnosing soft tissue injuries of the knee. However, there is a false positive rate ranging from 6% to 11% for meniscal tears.

ISAKOS classification of meniscal tears-illustration on 2D and 3D isotropic spin echo MR imaging

Magnetic Resonance Imaging is modality of choice for the non-invasive evaluation of meniscal tears. Accurate and uniform documentation of meniscal pathology is necessary for optimal multi-disciplinary communication, to guide treatment options and for validation of patient outcomes studies. The increasingly used ISAKOS arthroscopic meniscus tear classification system has been shown to provide sufficient interobserver reliability among the surgeons. However, the terminology is not in common use in the radiology world. In this article, the authors discuss the MR imaging appearances of meniscal tears based on ISAKOS classification on 2D and multiplanar 3D isotropic spin echo imaging techniques and illustrate the correlations of various meniscal pathologies with relevant arthroscopic images.

The role of the meniscotibial ligament in posteromedial rotational knee stability

PURPOSE

Tears of the posterior horn of the medial meniscus (PHMM) are very common in the ACL-deficient knee. Specific lesions of the PHMM have been described in the setting of ACL rupture: ramp lesions and injuries to the meniscotibial ligament. There are little data available regarding the role these lesions play in knee instability. The aim of this study is to analyse the biomechanical consequences of ramp and meniscotibial ligament lesions on knee stability. Our hypothesis was that these lesions would cause increased instability in the setting of ACL rupture.

METHODS

A cadaveric study was undertaken: ten knees were included for analysis. The biomechanical repercussions of different meniscoligamentous injuries were studied in four stages: stage 1 involved testing the intact knee, stage 2 after transection of the ACL, stage 3 following creation of a ramp lesion, and stage 4 after detachment of the meniscotibial ligament. Four parameters were measured during the experiment: anterior tibial translation under a force of 134 N, internal and external tibial rotation under a torque of 5 Nm, and valgus angulation under a torque of 10 Nm. Measurements were taken in four knee flexion positions: 0° or full extension, 30°, 70°, and 90° of flexion.

RESULTS

There was a statistically significant increase in anterior tibial translation for stage 2 (6.8 ± 1.3 mm, p ≤ 0.001), stage 3 (9.4 ± 1.3 mm, p ≤ 0.001), and stage 4 (9.3 ± 1.3 mm, p ≤ 0.001) compared to stage 1. There was no significant difference between stage 2 and stage 3 (2.6 mm, n.s.) or stage 4 (2.5 mm, n.s.). We did, however, demonstrate an increase in anterior tibial translation of 2.6 mm after the creation on a lesion of the PHMM compared to isolated division of the ACL, for all flexion angles combined. There was an increase in internal tibial rotation between stage 1 and stage 4 (3.2° ± 0.7°, p ≤ 0.001) and between stage 2 and stage 4 (2.0° ± 0.7°, p = 0.023). A significant difference was demonstrated for external rotation under 5 Nm torque between stages 4 and 1 (2.2° ± 0.5°, p ≤ 0.001) and between stages 4 and 2 (1.7° ± 0.5°, p = 0.007) for all knee flexion angles combined. No created lesion had a significant effect on medial laxity under a 10-Nm valgus torque at any degree of knee flexion.

CONCLUSION

Lesions of the posterior horn of the medial meniscus are frequent in cases of anterior cruciate ligament rupture. These lesions appear to play a significant role in knee stability. Ramp lesions increase the forces in the ACL, and the PHMM is a secondary restraint to anterior tibial translation. Lesions of the meniscotibial ligament may increase rotatory instability of the knee.

Posteromedial meniscal tears may be missed during anterior cruciate ligament reconstruction

PURPOSE

This study aimed to assess the benefit of using an arthroscopic intercondylar view and a posterior medial viewing portal during anterior cruciate ligament (ACL) reconstruction in the diagnosis of posterior horn of the medial meniscus (PHMM) tears. A secondary objective was to determine clinical and radiological risk factors for the PHMM.

METHODS

Forty-one patients undergoing isolated ACL reconstruction were prospectively evaluated. At ACL reconstruction, the PHMM was assessed using a standard 30° arthroscope in 3 sequential stages: a "classic" anterolateral portal view, an intercondylar view, and a view through a posteromedial portal.

RESULTS

Thirty-nine patients were included (12 female patients and 27 male patients). A posteromedial tear of the medial meniscus was found in 17 patients using the anterolateral portal view. The intercondylar view identified 4 new additional lesions and extensions of 3 previously identified lesions. The posteromedial portal view identified 6 new lesions and 5 extensions of known lesions compared with the anterolateral portal view. Two lesions seen through the posteromedial portal were not identified by either the anterolateral portal view or the intercondylar view.

CONCLUSIONS

Tears of the PHMM may be underdiagnosed by intraoperative assessment using only an anterolateral portal view during ACL reconstruction. The intercondylar view combined with a posteromedial portal aids in the diagnosis of PHMM tears and should be considered in routine ACL reconstruction to assess meniscal status, particularly when the interval from injury to surgery is prolonged.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Quantitative MRI T2 relaxation time evaluation of knee cartilage: comparison of meniscus-intact and -injured knees after anterior cruciate ligament reconstruction

BACKGROUND

Associated meniscal injury is well recognized at anterior cruciate ligament (ACL) reconstruction, and it is a known risk factor for osteoarthritis.

PURPOSE

To evaluate and characterize the postoperative appearance of articular cartilage after different meniscal treatment in ACL-reconstructed knees using T2 relaxation time evaluation on MRI.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A total of 62 consecutive patients who under ACL reconstruction were recruited in this study, including 23 patients undergoing partial meniscectomy (MS group), 21 patients undergoing meniscal repair (MR group), and 18 patients with intact menisci (MI group) at time of surgery. Clinical evaluation, including subjective functional scores and physical examination, was performed on the same day as the MRI examination and at follow-up times ranging from 2 to 4.2 years. The MRI multiecho sagittal images were segmented to determine the T2 relaxation time value of each meniscus and articular cartilage plate. Differences in each measurement were compared among groups.

RESULTS

No patient had joint-line tenderness or reported pain or clicking on McMurray test or instability. There were also no statistically significant differences in functional scores or medial or lateral meniscus T2 values among the 3 groups (P > .05 for both). There was a significantly higher articular cartilage T2 value in the medial femorotibial articular cartilage for the MS group (P < .01) and the MR group (P < .05) compared with that of the MI group, while there was no significant difference in articular cartilage T2 value between the MS and MR groups (P > .05) in each articular cartilage plate. The medial tibial articular cartilage T2 value had a significant positive correlation with medial meniscus T2 value (r = 0.287; P = .024) CONCLUSION: This study demonstrates that knees with meniscectomy or meniscal repair had articular cartilage degeneration at 2 to 4 years postoperatively, with higher articular cartilage T2 relaxation time values compared with the knees with an intact meniscus.