Meniscal tears of the knee: accuracy of MR imaging

Improving tissue contrast visualization in two-point Dixon MRI using dark-fat processing: application in clinical knee imaging

OBJECTIVE

To improve tissue contrast visualization in water-only images from two-point turbo spin-echo (TSE) Dixon MRI using dark-fat image processing and evaluate in retrospectively acquired clinical knee images.

MATERIALS AND METHODS

Clinical knee MRI datasets from 36 patients were retrospectively compiled under IRB approval. The dark-fat water-only images were generated and compared with the conventional water-only images from two-point TSE-Dixon MRI. The water-only images from 20 patients were analyzed: (i) qualitatively by two experienced musculoskeletal radiologists, for overall image quality, fat suppression, anatomical visualization, and the absence of artifacts, using Wilcoxon rank tests, and (ii) quantitatively using apparent signal-to-noise ratio (aSNR) and apparent contrast-to-noise ratio (aCNR) from regions of interest (ROIs) with paired t-test. In the remaining 16 patients, the number of cruciate ligament tears identified on MRI was tabulated and compared with arthroscopy results.

RESULTS

Compared to conventional water-only images, dark-fat water-only images showed improved fat suppression (reader 1, P < 0.0001; reader 2, P < 0.05), improved overall image quality by reader 1 (P < 0.001), and improved visualization of the sciatic nerve for reader 1 (P < 0.01), while there were no significant differences for the other anatomical structures. aSNR was significantly reduced for bone marrow fat (P < 0.0001), and aCNR between meniscus and articular cartilage was significantly improved (P < 0.0001). There were a higher number of posterior cruciate ligament tears identified in MRI compared to arthroscopy.

CONCLUSION

Dark-fat processed water-only images improved fat suppression and tissue contrast visualization, particularly sciatic nerves, compared to conventional water-only images from two-point TSE-Dixon MR imaging.

Survivorship and outcomes of intra- and perimeniscal corticosteroids injections with structured physiotherapy for degenerative medial meniscus tears

BACKGROUND

Degenerative medial meniscus tears are a common pathology in the general population. Recent randomized trials demonstrated non-superiority of arthroscopic partial meniscectomy over conservative management. However, there is a paucity of information regarding the outcomes of combined conservative treatments.

HYPOTHESIS

It was hypothesized that combined intra- and perimeniscal corticosteroid injections with structured physiotherapy, for degenerative medial meniscus tears, would result in high surgery-free and second injection-free survivorship.

METHODS

A retrospective review of 671 patients with symptomatic degenerative medial meniscus tears, who received intra- and perimeniscal corticosteroids injection combined with structured physiotherapy, was conducted. An ultrasound-guided injection of Triamcinolone Hexacetonide 20 mg/ml comprised; 1.5 ml intra-meniscal,1.5 ml in the meniscal wall, and 2 ml in the peri-meniscal space, was performed. Surgery free- and a second injection free-survivorship were analysed. Western Ontario and Macmaster University scores (WOMAC), Tegner activity scores, patient satisfaction, return-to-work status and average time to return to work were recorded.

RESULTS

A total of 481 patients who met the inclusion criteria were included. The mean age was 51.1 ± 7.9 years. At five years post-procedure, surgery-free, and second injection-free survivorship of the ipsilateral knee was 83%, and 52%, respectively. A multivariate analysis adjusting survival on parametric risk factors identified that only effusion before steroid injection was an independent risk factor of treatment failure. At a mean follow-up of 4 ± 2 years, there was an improvement in WOMAC scores by 5.2 ± 4.9 for pain, by 2 ± 2 for stiffness, by 7.3 ± 7.4 for function, and by 12.4 ± 12.7 for the global scores. Additionally, there was significant improvement in the Tegner activity scores (All p < 0.001). Knee effusion and advanced osteoarthritis (Kellgren-Lawrence > III) were significantly associated with poorer outcomes; p < 0.003 and p < 0.0004, respectively.

CONCLUSION

A combination of intra- and perimeniscal corticosteroid injections and structured physiotherapy for degenerative medial meniscus tears, results in high surgery-free (83%) and second injection-free (52%) survivorship, as well as, effective clinical outcomes and satisfaction at 5 years.

LEVEL OF EVIDENCE

IV; Retrospective Case Series.

Deep Learning-Enhanced Accelerated 2D TSE and 3D Superresolution Dixon TSE for Rapid Comprehensive Knee Joint Assessment

OBJECTIVES

The aim of this study was to evaluate the use of a multicontrast deep learning (DL)-reconstructed 4-fold accelerated 2-dimensional (2D) turbo spin echo (TSE) protocol and the feasibility of 3-dimensional (3D) superresolution reconstruction (SRR) of DL-enhanced 6-fold accelerated 2D Dixon TSE magnetic resonance imaging (MRI) for comprehensive knee joint assessment, by comparing image quality and diagnostic performance with a conventional 2-fold accelerated 2D TSE knee MRI protocol.

MATERIALS AND METHODS

This prospective, ethics-approved study included 19 symptomatic adult subjects who underwent knee MRI on a clinical 3 T scanner. Every subject was scanned with 3 DL-enhanced acquisition protocols in a single session: a clinical standard 2-fold in-plane parallel imaging (PI) accelerated 2D TSE-based protocol (5 sequences, 11 minutes 23 seconds) that served as a reference, a DL-reconstructed 4-fold accelerated 2D TSE protocol combining 2-fold PI and 2-fold simultaneous multislice acceleration (5 sequences, 6 minutes 24 seconds), and a 3D SRR protocol based on DL-enhanced 6-fold accelerated (ie, 3-fold PI and 2-fold simultaneous multislice) 2D Dixon TSE MRI (6 anisotropic 2D Dixon TSE acquisitions rotated around the phase-encoding axis, 6 minutes 24 seconds). This resulted in a total of 228 knee MRI scans comprising 21,204 images. Three readers evaluated all pseudonymized and randomized images in terms of image quality using a 5-point Likert scale. Two of the readers (musculoskeletal radiologists) additionally evaluated anatomical visibility and diagnostic confidence to assess normal and pathological knee structures with a 5-point Likert scale. They recorded the presence and location of internal knee derangements, including cartilage defects, meniscal tears, tears of ligaments, tendons and muscles, and bone injuries. The statistical analysis included nonparametric Friedman tests, and interreader and intrareader agreement assessment using the weighted Fleiss-Cohen kappa (κ) statistic. P values of less than 0.05 were considered statistically significant.

RESULTS

The evaluated DL-enhanced 4-fold accelerated 2D TSE protocol provided very similar image quality and anatomical visibility to the standard 2D TSE protocol, whereas the 3D SRR Dixon TSE protocol scored less in terms of overall image quality due to reduced edge sharpness and the presence of artifacts ( P < 0.001). Subjective signal-to-noise ratio, contrast resolution, fluid brightness, and fat suppression were good to excellent for all protocols. For 1 reader, the Dixon method of the 3D SRR protocol provided significantly better fat suppression than the spectral fat saturation applied in the standard 2D TSE protocol ( P < 0.05). The visualization of knee structures with 3D SRR Dixon TSE was very similar to the standard protocol, except for cartilage, tendons, and bone, which were affected by the presence of reconstruction and aliasing artifacts ( P < 0.001). The diagnostic confidence of both readers was high for all protocols and all knee structures, except for cartilage and tendons. The standard 2D TSE protocol showed a significantly higher diagnostic confidence for assessing tendons than 3D SRR Dixon TSE MRI ( P < 0.01). The interreader and intrareader agreement for the assessment of internal knee derangements using any of the 3 protocols was substantial to almost perfect (κ = 0.67-1.00). For cartilage, the interreader agreement was substantial for DL-enhanced accelerated 2D TSE (κ = 0.79) and almost perfect for standard 2D TSE (κ = 0.98) and 3D SRR Dixon TSE (κ = 0.87). For menisci, the interreader agreement was substantial for 3D SRR Dixon TSE (κ = 0.70-0.80) and substantial to almost perfect for standard 2D TSE (κ = 0.80-0.99) and DL-enhanced 2D TSE (κ = 0.87-1.00). Moreover, the total acquisition time was reduced by 44% when using the DL-enhanced accelerated 2D TSE or 3D SRR Dixon TSE protocol instead of the conventional 2D TSE protocol.

CONCLUSIONS

The presented DL-enhanced 4-fold accelerated 2D TSE protocol provides image quality and diagnostic performance similar to the standard 2D protocol. Moreover, the 3D SRR of DL-enhanced 6-fold accelerated 2D Dixon TSE MRI is feasible for multicontrast 3D knee MRI as its diagnostic performance is comparable to standard 2-fold accelerated 2D knee MRI. However, reconstruction and aliasing artifacts need to be further addressed to guarantee a more reliable visualization and assessment of cartilage, tendons, and bone. Both the 2D and 3D SRR DL-enhanced protocols enable a 44% faster examination compared with conventional 2-fold accelerated routine 2D TSE knee MRI and thus open new paths for more efficient clinical 2D and 3D knee MRI.

Knee ligament and meniscus injuries in children and teenagers

Knee ligament and meniscus injuries in children and teenagers are becoming more numerous because of increased sports participation but also better diagnosis. Meniscus injuries occur either in a normal meniscus or due to a congenital anomaly. The diagnosis is made clinically and confirmed by MRI. Treatment depends on the findings: meniscoplasty for discoid meniscus and primary repair of meniscus tears. Meniscus preservation is the rule. Injuries to the central pivot of the knee typically involve either the anterior cruciate ligament (ACL) or the tibial spine. Age, anatomy and the mechanism of injury determine the specific nature of the injury. The treatment of tibial spine fractures is highly standardized and typically surgical, with the aim of limiting residual laxity. ACL tears can be treated either by primary repair or non-surgically with guided rehabilitation. ACL reconstruction in skeletally immature patients is feasible as long as the growth plates are protected. The rate of residual laxity or retear is lower when anterolateral reconstruction is performed simultaneously. LEVEL OF EVIDENCE: Expert opinion.

Qualitative Magnetic Resonance Imaging Assessment of the Semimembranosus Tendon in Patients with Medial Meniscal Tears

BACKGROUND

To determine if there is an association between semimembranosus tendinosis and medial meniscal tears using MRI.

METHODS

A retrospective review of knee 3T MRI scans was performed to determine the presence or absence of medial meniscal tears in patients with semimembranosus tendinosis. All studies were interpreted by two musculoskeletal radiologists. Univariate association for the presence of semimembranosus tendinosis and medial meniscal tears was performed with a Chi-square test followed by logistic regression modelling among statistically significant associations.

RESULTS

A total of 150 knee MRI scans were reviewed (age 32.8 ± 7.1 years; 70 females). Semimembranosus tendinosis was present in 66 knees (44%) in the patient population. Semimembranosus tendinosis was present in 81% of patients with meniscal tears versus 36% of patients without meniscal tears (p < 0.0001). This association remained statistically significant when adjusted for age and sex with an adjusted odds ratio of 7.0 (p < 0.0003). Models adjusted for the above covariates and containing the interaction term produced an adjusted odds ratio of 13.0 (p < 0.0001) in men, while in women this association was non-significant with an adjusted odds ratio of 2.0 (p = 0.42).

CONCLUSIONS

Subjects with semimembranosus tendinosis were seven times more likely to have medial meniscal tears even when adjusting for sex and age. This could help guide the appropriate postmeniscal repair rehabilitation protocol.

Excellent accuracy of magnetic resonance imaging for diagnosis of discoid meniscus tears: A systematic review and meta-analysis

Purpose

The discoid meniscus (DM) is distinguished by its thickened, disc-shaped formation, which extends over the tibial plateau. The likelihood of developing osteoarthritis escalates if a DM tear remains undiagnosed and untreated. While DM tears can be diagnosed through arthroscopy, the high cost, invasive nature and limited availability of this procedure highlight the need for a better diagnostic modality. This study aims to determine the accuracy of magnetic resonance imaging (MRI) in diagnosing DM tears.

Methods

A systematic review was conducted to gather articles with at least 10 cases on the comparison of MRI and arthroscopy as the gold standard for DM tear diagnosis. Stata and MetaDisc were used to conduct the statistical analysis. The quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.

Results

Five diagnostic performance studies, derived from four original research papers involving 305 patients, were evaluated. Based on the pooled data, the sensitivity, specificity, diagnostic odds ratio, positive limit of detection and negative limit of detection were found to be 0.87 (95% confidence interval [CI], 0.82-0.91) and 0.84 (95% CI, 0.75-0.90), 32.88 (95% CI, 5.81-186.02), 5.22 (95% CI, 1.71-15.92) and 0.18 (95% CI, 0.09-0.38), respectively. A hierarchical summary receiver operating characteristic curve with an area under the curve of 0.92 was generated.

Conclusion

This meta-analysis demonstrates that MRI has excellent sensitivity and specificity for diagnosing DM tears. Despite its lower accuracy compared to arthroscopy, MRI can be used in symptomatic patients as a viable alternative to arthroscopy due to its inherent advantages.

Level of Evidence

Level IV.

Horizontal Cleavage Meniscus Tear: "The Quad Tendon Augmentation Technique"

The management of medial meniscus horizontal cleavage tears can be challenging. Currently, several treatment options, including nonoperative and surgical options, have been proposed in the literature. Different repair techniques aiming to promote the healing process have been reported and have shown good outcomes. However, recurrent parameniscal cysts and decreased meniscal volume have also been reported. In this Technical Note, a novel surgical technique to repair a horizontal cleavage tear of the posterior horn of the medial meniscus is reported in young patients. The technique uses a strip of autologous quadriceps tendon to fill the void between the upper and lower meniscal leaflets followed by an all-inside compression suture. Both of these technical features aim to overcome the limitations of current repair techniques.

Degenerative Meniscus Tears Treated Nonoperatively With Platelet-Rich Plasma Yield Variable Clinical and Imaging Outcomes: A Systematic Review

Purpose

To perform a systematic review on clinical and radiologic outcomes for meniscus tears treated nonoperatively with platelet-rich plasma (PRP).

Methods

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using keywords and Boolean operators in SCOPUS, PubMed, Medline, and the Cochrane Central Register for Controlled Trials in April 2023. Inclusion criteria were limited to Level I to IV human studies reporting on outcomes of meniscus tears treated nonoperatively with PRP.

Results

A total of 6 studies, consisting of 184 patients, were identified. There was 1 Level I study and 5 Level IV studies. Mean patient age was 47.8 ± 7.9 years, with 62% (n = 114/184) being female. The medial meniscus was treated in 95.7% (n = 157/164) of patients. Mean follow-up ranged from 75.9 days to 31.9 months. Meniscus tears were generally described as chronic, degenerative, or intrasubstance. In 4 studies, magnetic resonance imaging revealed variable improvement in meniscus grade with complete healing in 0% to 44% of patients and partial healing in 0% to 40% of patients. Four of 5 studies reported significant statistical improvement in pain from baseline to final follow-up. Studies reporting on clinical outcomes showed significant improvements Lysholm score (2 studies), Knee injury and Osteoarthritis Outcome Score total score (2 studies), and Tegner score (1 study). Successful return to sport occurred in 60% to 100% of patients. Two studies reported that most patients were either very satisfied or satisfied following treatment.

Conclusions

The use of PRP injections for the treatment of meniscus tears led to variable results based on postoperative magnetic resonance evaluation and improvements in clinical outcomes, although the clinical significance remains unclear. The heterogeneity of PRP protocols, short-term follow-up, and lack of comparative studies limit findings.

Level of Evidence

Level IV, systematic review of Level I to IV studies.

MRI Criteria for Healing at 1 Year After Repair of a Traumatic Meniscal Tear

BACKGROUND

Meniscal repair for a traumatic meniscal tear is increasingly used to preserve the meniscus. Interpreting postoperative magnetic resonance imaging (MRI) scans remains challenging, especially in symptomatic patients. There is a lack of reliable MRI criteria to affirm the healed character of a traumatic meniscal injury repair.

PURPOSE

To identify relevant MRI criteria for meniscal healing after meniscal repair.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We prospectively included all patients with a traumatic meniscal injury who underwent either an isolated meniscal repair or a repair during a concomitant anterior cruciate ligament reconstruction. A standardized preoperative and postoperative clinical evaluation was performed, along with collection of functional scores-Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee, Lysholm Score, and 36-Item Short Form Health Survey. An MRI scan was performed 1 year postoperatively and compared with the preoperative MRI scan. The following MRI aspects were analyzed: variation of morphology and fat-saturated (FS) T2 intensity signal and pre- and postoperative tear diastasis measurement.

RESULTS

Fifty patients (age, mean ± SD, 28.7 ± 8.5 years [range, 16-45 years]) who were 1 year postoperative were included. All patients were considered clinically healed had the same MRI characteristics. A signal change (FS T2) was observed from a high signal intensity fluid to a nonfluid moderate signal intensity. The morphology of the lesion was more complex: from the initial lesion, line ramifications appeared, creating the appearance of tree branches. The tear diastasis decreased (from 2.3 ± 0.5 mm [range, 1.3-3.5] to 1.1 ± 0.28 mm [range, 0.5-1.5]).

CONCLUSION

MRI criteria confirming meniscal healing after traumatic meniscal repair at 1 year were identified: a change in the intrameniscal signal becoming nonfluid and moderate in intensity; a reduction in tear diastasis to <1.5 mm; and a change in the signal morphology of the repaired meniscus.

Highly accelerated knee magnetic resonance imaging using deep neural network (DNN)-based reconstruction: prospective, multi-reader, multi-vendor study

In this prospective, multi-reader, multi-vendor study, we evaluated the performance of a commercially available deep neural network (DNN)-based MR image reconstruction in enabling accelerated 2D fast spin-echo (FSE) knee imaging. Forty-five subjects were prospectively enrolled and randomly divided into three 3T MRIs. Conventional 2D FSE and accelerated 2D FSE sequences were acquired for each subject, and the accelerated FSE images were reconstructed and enhanced with DNN-based reconstruction software (FSE-DNN). Quantitative assessments and diagnostic performances were independently evaluated by three musculoskeletal radiologists. For statistical analyses, paired t-tests, and Pearson's correlation were used for image quality comparison and inter-reader agreements. Accelerated FSE-DNN reduced scan times by 41.0% on average. FSE-DNN showed better SNR and CNR (p < 0.001). Overall image quality of FSE-DNN was comparable (p > 0.05), and diagnostic performances of FSE-DNN showed comparable lesion detection. Two of cartilage lesions were under-graded or over-graded (n = 2) while there was no significant difference in other image sets (n = 43). Overall inter-reader agreement between FSE-conventional and FSE-DNN showed good agreement (R2 = 0.76; p < 0.001). In conclusion, DNN-based reconstruction can be applied to accelerated knee imaging in multi-vendor MRI scanners, with reduced scan time and comparable image quality. This study suggests the potential for DNN-accelerated knee MRI in clinical practice.

Magnetic resonance imaging assessments for knee segmentation and their use in combination with machine/deep learning as predictors of early osteoarthritis diagnosis and prognosis

Knee osteoarthritis (OA) is a prevalent and disabling disease that can develop over decades. This disease is heterogeneous and involves structural changes in the whole joint, encompassing multiple tissue types. Detecting OA before the onset of irreversible changes is crucial for early management, and this could be achieved by allowing knee tissue visualization and quantifying their changes over time. Although some imaging modalities are available for knee structure assessment, magnetic resonance imaging (MRI) is preferred. This narrative review looks at existing literature, first on MRI-developed approaches for evaluating knee articular tissues, and second on prediction using machine/deep-learning-based methodologies and MRI as input or outcome for early OA diagnosis and prognosis. A substantial number of MRI methodologies have been developed to assess several knee tissues in a semi-quantitative and quantitative fashion using manual, semi-automated and fully automated systems. This dynamic field has grown substantially since the advent of machine/deep learning. Another active area is predictive modelling using machine/deep-learning methodologies enabling robust early OA diagnosis/prognosis. Moreover, incorporating MRI markers as input/outcome in such predictive models is important for a more accurate OA structural diagnosis/prognosis. The main limitation of their usage is the ability to move them in rheumatology practice. In conclusion, MRI knee tissue determination and quantification provide early indicators for individuals at high risk of developing this disease or for patient prognosis. Such assessment of knee tissues, combined with the development of models/tools from machine/deep learning using, in addition to other parameters, MRI markers for early diagnosis/prognosis, will maximize opportunities for individualized risk assessment for use in clinical practice permitting precision medicine. Future efforts should be made to integrate such prediction models into open access, allowing early disease management to prevent or delay the OA outcome.

No evidence in support of arthroscopic partial meniscectomy in adults with degenerative and nonobstructive meniscal symptoms: a level I evidence-based systematic review

PURPOSE

It is unclear whether the results of arthroscopic partial meniscectomy (APM) are comparable to a structured physical therapy (PT). This systematic review investigated efficacy of APM in the management of symptomatic meniscal damages in middle aged patients. Current available randomised controlled trials (RCTs) which compared APM performed in isolation or combined with physical therapy versus sham arthroscopy or isolated physical therapy were considered in the present systematic review.

METHODS

This systematic review was conducted according to the 2020 PRISMA statement. All the level I RCTs which investigated the efficacy of AMP were accessed. Studies which included elderlies with severe OA were not eligible, nor were those in which APM was combined with other surgical intervention or in patients with unstable knee or with ligaments insufficiency. The risk of bias was assessed using the software Review Manager 5.3 (The Nordic Cochrane Collaboration, Copenhagen). To rate the quality of evidence of collected outcomes, the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was used.

RESULTS

Data from 17 studies (2037 patients) were collected. 48.5% (988 of 2037 patients) were women. The mean age of the patients was 52.7 ± 3.9 years, the mean BMI 27.0 ± 1.3 kg/m². The current evidence suggests no difference in functional PROMs (quality of the evidence: high), clinical PROMs (quality of the evidence: high), pain (quality of the evidence: high), quality of life (quality of the evidence: high), physical performance measures (quality of the evidence: moderate), and OA progression (quality of the evidence: moderate).

CONCLUSIONS

The benefits of APM in adults with degenerative and nonobstructive meniscal symptoms are limited. The current evidence reports similarity in the outcome between APM and PT. Further long-term RCTs are required to investigate whether APM and PT produce comparable results using validated and reliable PROMs. Moreover, future RCTs should investigate whether patients who might benefit from APM exist, clarifying proper indications and outcomes. High quality investigations are strongly required to establish the optimal PT regimes.

LEVEL OF EVIDENCE

Level I.

Clinical outcomes, healing rate, and presence of peri-meniscal cysts after all-inside meniscal repair in combination with anterior cruciate ligament reconstruction: a prospective comparative study with magnetic resonance imaging assessment

PURPOSE

Meniscal repairs are the most common associated procedures during ACL reconstruction, but they present challenging indications and possible risks of complications or failures. The aim of the present study is to assess the clinical outcomes of all-inside meniscal repairs in the setting of ACL reconstruction.

METHODS

Twenty patients with ACL reconstruction and all-inside meniscal repair were compared to 20 patients with isolated ACL reconstruction. All patients were prospectively evaluated pre-operatively, at four month, and 18-month follow-up with KT-1000, Kira accelerometer for pivot-shift, KOOS, Marx score, and SF-36. Meniscal healing and presence of peri-meniscal cysts were assessed on standardized 1.5-T MRIs performed at 18 months.

RESULTS

Twenty-one meniscal repairs were performed in 20 patients (81% medial, 19% lateral). At 18 months, 48% had complete healing, 38% had incomplete healing, and 14% had no healing. Peri-meniscal cysts were present in 33% of cases. Worst pre-operative KOOS pain (p = 0.0435) and ADL (p = 0 .0201) were present in patients with meniscal lesion, while no differences were present at four months and 18 months between patients with or without meniscal repair (p > 0.05). No significant differences were noted stratifying patients according to meniscal healing or cyst presence, except of a lower Qol KOOS subscale in patients with peri-meniscal cysts (p = 0.0430).

CONCLUSIONS

Meniscal repairs produced good short-term results when performed in combination to ACL reconstruction. Full or partial healing at MRI was present in 86% of cases. One patient out of three developed peri-meniscal cysts.

Side-to-side anterior tibial translation on monopodal weightbearing radiographs as a sign of knee decompensation in ACL-deficient knees

PURPOSE

To evaluate the influence of time from injury and meniscus tears on the side-to-side difference in anterior tibial translation (SSD-ATT) as measured on lateral monopodal weightbearing radiographs in both primary and secondary ACL deficiencies.

METHODS

Data from 69 patients (43 males/26 females, median age 27-percentile 25-75: 20-37), were retrospectively extracted from their medical records. All had a primary or secondary ACL deficiency as confirmed by MRI and clinical examination, with a bilateral weightbearing radiograph of the knees at 15°-20° flexion available. Meniscal status was assessed on MRI images by a radiologist and an independent orthopaedic surgeon. ATT and posterior tibial slope (PTS) were measured on the lateral monopodal weightbearing radiographs for both the affected and the contralateral healthy side. A paired t-test was used to compare affected/healthy knees. Independent t-tests were used to compare primary/secondary ACL deficiencies, time from injury (TFI) (≤ 4 years/ > 4 years) and meniscal versus no meniscal tear.

RESULTS

ATT of the affected side was significantly greater than the contralateral side (6.2 ± 4.4 mm vs 3.5 ± 2.8 mm; p < 0.01). There was moderate correlation between ATT and PTS in both the affected and healthy knees (r = 0.43, p < 0.01 and r = 0.41, p < 0.01). SSD-ATT was greater in secondary ACL deficiencies (4.7 ± 3.8 vs 1.9 ± 3.2 mm; p < 0.01), patients with a TFI greater than 4 years (4.2 ± 3.8 vs 2.0 ± 3.0 mm; p < 0.01) and with at least one meniscal tear (3.9 ± 3.8 vs 0.7 ± 2.2 mm; p < 0.01). Linear regression showed that, in primary ACL deficiencies, SSD-ATT was expected to increase (+ 2.7 mm) only if both a meniscal tear and a TFI > 4 years were present. In secondary ACL deficiencies, SSD-ATT was mainly influenced by the presence of meniscal tears regardless of the TFI.

CONCLUSION

SSD-ATT was significantly greater in secondary ACL deficiencies, patients with a TFI greater than 4 years and with at least one meniscal tear. These results confirm that SSD-ATT is a time- and meniscal-dependent parameter, supporting the concept of gradual sagittal decompensation in ACL-deficient knees, and point out the importance of the menisci as secondary restraints of the anterior knee laxity. Monopodal weightbearing radiographs may offer an easy and objective method for the follow-up of ACL-injured patients to identify early signs of soft tissue decompensation under loading conditions.

LEVEL OF EVIDENCE

Level III.

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.

3D CAIPIRINHA SPACE versus standard 2D TSE for routine knee MRI: a large-scale interchangeability study

OBJECTIVE

To perform a large-scale interchangeability study comparing 3D controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) sampling perfection with application optimized contrast using different flip angle evolutions (SPACE) TSE with standard 2D TSE for knee MRI.

METHODS

In this prospective study, 250 patients underwent 3 T knee MRI, including a multicontrast 3D CAIPIRINHA SPACE TSE (9:26 min) and a standard 2D TSE protocol (12:14 min). Thirty-three (13%) patients had previous anterior cruciate ligament and/or meniscus surgery. Two radiologists assessed MRIs for image quality and identified pathologies of menisci, ligaments, and cartilage by using a 4-point Likert scale according to the level of diagnostic confidence. Interchangeability of the protocols was tested under the same-reader scenario using a bootstrap percentile confidence interval. Interreader reliability and intermethod concordance were also evaluated.

RESULTS

Despite higher image quality and diagnostic confidence for standard 2D TSE compared to 3D CAIPIRINHA SPACE TSE, the protocols were found interchangeable for diagnosing knee abnormalities, except for patellar (6.8% difference; 95% CI: 4.0, 9.6) and trochlear (3.6% difference; 95% CI: 0.8, 6.6) cartilage defects. The interreader reliability was substantial to almost perfect for 2D and 3D MRI (range κ, 0.785-1 and κ, 0.725-0.964, respectively). Intermethod concordance was almost perfect for all diagnoses (range κ, 0.817-0.986).

CONCLUSION

Multicontrast 3D CAIPIRINHA SPACE TSE and standard 2D TSE protocols perform interchangeably for diagnosing knee abnormalities, except for patellofemoral cartilage defects. Despite the radiologist's preference for 2D TSE imaging, a pursuit towards time-saving 3D TSE knee MRI is justified for routine practice.

KEY POINTS

• Multicontrast 3D CAIPIRINHA SPACE and standard 2D TSE protocols perform interchangeably for diagnosing knee abnormalities, except for patellofemoral cartilage defects. • Radiologists are more confident in diagnosing knee abnormalities on 2D TSE than on 3D CAIPIRINHA SPACE TSE MRI. • Despite the radiologist's preference for 2D TSE, a pursuit towards accelerated 3D TSE knee MRI is justified for routine practice.

Good Clinical Success Rates Are Seen 5 Years After Meniscal Repair in Patients Regularly Undertaking Extreme Flexion

Purpose

To report the functional and radiologic outcomes of meniscal repair healing in a cohort of patients with a high demand for loaded extreme flexion angles after undergoing meniscal repair.

Methods

We performed a retrospective clinical and radiologic evaluation of patients who perform extreme knee flexion activities on a daily basis at a minimum follow-up of 2 years after meniscal repair. International Knee Documentation Committee, Lysholm, and Tegner scores were obtained, and clinical examinations and radiologic (magnetic resonance imaging and radiography) evaluations were performed.

Results

Of 47 eligible patients, 39 patients (40 knees) were available for review with an average follow-up time of 5 years (range, 2-9 years). The average age was 26.7 years (range, 19-39 years); 38 patients were men. The average time from injury to surgery was 20.9 months (range, 3 days to 120 months). Associated anterior cruciate ligament injury was present in 31 knees, but only 20 underwent simultaneous anterior cruciate ligament surgery. The mean International Knee Documentation Committee score was 88.9 (range, 53-99). The mean Lysholm score was 90.9 (range, 48-100). The mean Tegner activity level dropped from 6.18 before injury to 5.51 at the time of evaluation. According to the Barrett criteria for clinical outcomes, complete healing was observed in 29 of 40 knees (72.5%). There was a statistically significant correlation between the functional outcomes and the clinical outcomes (P = .008). On magnetic resonance imaging, 22 of 38 knees (57.9%) showed completely healed menisci.

Conclusions

The results of this study suggest that loaded deep knee flexion may be safe after a period of restricted rehabilitation, and clinical and radiologic tissue healing is independent of the overall functional outcome.

Level of Evidence

Level IV, case series with subgroup analysis.

Diagnostic value of clinical tests and Mri for meniscal injury in patients with anterior cruciate ligament injury: Case series study

Introduction and importance

Meniscal tear is one of the most common knee injuries and knee surgery procedures. It is frequently associated with an anterior cruciate ligament (ACL) injury. We conducted this study, on patients with ACL reconstruction surgeries, which were occasionally accompanied by meniscal tears, in order to determine the diagnostic value of clinical examinations for meniscal tear, both individually and in combination, in correlations to magnetic resonance imaging (MRI) scans, with the goal of improving clinical diagnosis for patients with meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.

Case presentation

50 patients were thoroughly clinically examined, using Joint line tenderness, Thessaly test, McMurray's test, Apley's test followed by MRI, before their scheduled ACL reconstruction arthroscopic surgeries. The meniscal tears were then identified during the procedure, and were treated, if necessary. The data before and after the surgery was taken into calculating, with arthroscopic findings serving as the gold standard. Results: the sensitivity, specificity and accuracy of each clinical tests and MRI scans respectively were: for medial meniscus, Joint line tenderness (70%; 53,3%; 60%); McMurray's test (80%; 73,3%: 76%); Apley's test (65%; 70%; 68%); Thessaly test(70%; 76,7%; 74%); MRI (90%; 83,3%; 86%); lateral meniscus: Joint line tenderness (73%; 66,7%; 70%); McMurray's test (69,2%; 75%: 72%); Apley's test (69,2%; 70,8%; 70%); Thessaly test (73,1%; 75%; 74%); MRI (88,5%; 87,5%; 88%). However, when combining at least two positive tests into a single composite test, the diagnostic value is considerably enhanced with sensitivity, specificity and accuracy of 85%, 73,3%, 78% for medial meniscus, 92,3%, 87,5%, 90% for lateral meniscus.

Clinical discussion

Clinical tests are essential for diagnosis of meniscal tears, although inconsistent. A composite test consisting of at least two positive tests can considerably enhance the diagnostic value, even comparable to MRI scans. However, after the clinical examination, MRI is still necessary for the diagnostic process of meniscal injuries in particular, as well as meniscal injuries associated with cruciate ligament knee injuries.

Conclusion

The combination of clinical tests and MRI images will give a precise diagnosis as well as surgical indication for meniscus injury in patients with anterior cruciate ligament tear.

•

Meniscus tear is frequently associated with ACL injury

•

Identifying, classifying and grading meniscus lesion is very important because it can assist surgeon in providing appropriate treatment plans (meniscectomy or repair) and having an accurate prognosis for patients.

•

Determine the diagnostic value in term of clinical in correlation with preoperative MRI images is the purpose of this study

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.

Increased MRI Signal Intensity of Allografts in the Midterm Period After Meniscal Allograft Transplant: An Evaluation of Clinical Significance According to Location and Morphology

Background:

Magnetic resonance imaging (MRI) is an effective tool for objective evaluation after meniscal allograft transplant (MAT). Little is known about the association between MRI features of allograft and clinical outcomes.

Purpose/Hypothesis:

To assess the degree and location of signal intensity (SI) as well as the morphology of allografts on MRI after MAT and evaluate the association between clinical outcomes and MRI features in the midterm period. It was hypothesized that a high SI accompanied by a deformed allograft in specific locations on MRI would be associated with inferior clinical outcomes.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were patients who underwent MAT with fresh-frozen allografts and had >3 years of follow-up with 3.0-T MRI scans. Allograft status was assessed by SI on MRI as grade 0 (normal), grade 1 (globular increased SI not adjacent to the articular surface), grade 2 (linear SI within the meniscus), or grade 3 (increased SI extended to the articular surface). Allograft morphology was assessed by the presence of distorted contours. Clinical outcomes were evaluated using the Lysholm score. The association between clinical outcomes and MRI findings was assessed by multiple linear regression analysis.

Results:

A total of 138 patients (156 MAT procedures: 132 lateral, 24 medial) with a mean follow-up period of 55.4 ± 19.9 months (range, 36-110 months) were enrolled in this study. Grade 3 SI was observed in the posterior meniscus root and posterior third of the allograft in 39 (25%) and 62 (39.7%) MATs, respectively. Among the 62 MATs with grade 3 SI in the posterior third of the allograft, 34 (54.8%) were accompanied by distorted allograft contour. The presence of grade 3 SI with distorted contour in the posterior third of the allograft was significantly associated with inferior outcomes (β = –6.5 [95% CI, –12.5 to –0.5]; P < .035), as was the presence of grade 3 SI in the posterior meniscus root (β = –5.5 [95% CI, –10.5 to –0.4]; P < .034).

Conclusion:

On MRI evaluation in the midterm period after MAT, grade 3 SIs of the meniscal allograft were observed in about a third of the cases, and the association with clinical outcomes was dependent on the specific location and morphology of the allograft on MRI.

Clinical presentation, MRI and clinical outcome scores do not accurately predict an important meniscal tear in a symptomatic discoid meniscus

PURPOSE

Discoid menisci can be symptomatic from instability or a tear. A torn discoid meniscus is likely to require repair to preserve meniscal function and should not be missed. This is the first study to evaluate a range of pre-operative methods to predict the likelihood of a torn discoid meniscus.

METHODS

A retrospective analysis of prospectively collected data was performed. Clinical, radiographic and operative data were reviewed. Patients were grouped based on the presence of a tear or not during surgery. All patients underwent MRI scans pre-operatively which were validated with arthroscopy findings to calculate sensitivity. All patients completed Pedi-KOOS and Pedi-IKDC pre-operative scores.

RESULTS

There were 32 discoid menisci in 27 patients. Mean age at surgery was 10.4 years (6-16). Nineteen patients were female. Seventeen menisci were identified as torn at time of arthroscopy (53%), 15 were unstable but not torn. Clinical findings did not differentiate between the torn or unstable menisci. MRI was only 75% sensitive and 50% specific at identifying a torn discoid meniscus. There was no statistical difference between KOOS-child (n.s.) and Pedi-IKDC (n.s.) scores between the groups.

CONCLUSION

MRI is neither sensitive nor specific at identifying tears in discoid menisci. There is no difference in pre-operative outcome scores for patients with a torn or unstable discoid meniscus; pre-operative PROMs are a poor predictor of a meniscal tear. This study emphasises that pre-operative tests and clinical findings are not conclusive for identifying a meniscal tear and the operating surgeon should be vigilant in identifying and repairing tears at the time of surgery. Pre-operative findings poorly correlate to arthroscopic findings and potential surgical interventions required. Patients and parents/carers should, therefore, be appropriately counselled prior to surgery that post-operative measures are dependent on intra-operative findings and not pre-operative findings in patients.

LEVEL OF EVIDENCE

III.

Meniscal Injuries: Mechanism and Classification

Meniscal tears may be managed through conservative physical therapy and nonsteroidal anti-inflammatory medications or operative intervention. Meniscal repair is superior to partial meniscectomy with better functional outcomes and less severe degenerative changes over time. Surgical advances in operative techniques, modern instrumentation and biological enhancements collectively improve healing rates of meniscal repair. However, failed repair is not without consequences and can negative impact patient outcomes. Therefore, it is imperative for surgeons to have a thorough understanding of the vascular zones and biomechanical classifications of meniscal tears in order to best determine the most appropriate treatment.

Pediatric discoid meniscus: can magnetic resonance imaging features coupled with clinical symptoms predict the need for surgery?

BACKGROUND

Magnetic resonance imaging (MRI) criteria for evaluating discoid meniscus is limited in the pediatric population.

OBJECTIVE

To assess MRI features of intact discoid meniscus and correlate with clinical outcomes.

MATERIALS AND METHODS

In this institutional review board (IRB)-approved retrospective cohort study, knee MRIs at our institution from 2008 to 2019 were reviewed. The inclusion criterion was diagnosis of discoid meniscus on MRI. Exclusion criteria were torn discoid meniscus at presentation, previous meniscal surgery and confounding knee conditions. MRI features of discoid meniscus collected were craniocaudal dimension, transverse dimension, transverse dimension to tibial plateau (TV:TP) ratio and increased intrameniscal signal. The clinical course was reviewed for knee pain, mechanical symptoms and treatment type.

RESULTS

Two hundred and nineteen of 3,277 (6.7%) patients had discoid meniscus. Of the 219 patients, 71 (32.4%) satisfied inclusion criteria. Seven patients had discoid meniscus of both knees resulting in 78 discoid menisci. The average patient age was 11.1 years (min: 2.0, max: 17.0). The average follow-up was 30.6 months. Of the 78 discoid menisci, 14 (17.9%) required surgery. Increased intrameniscal signal was found more in discoid meniscus requiring surgery (surgical: 10/14, nonsurgical: 19/64, P=0.009). Surgically treated discoid meniscus had a statistically significant increase in transverse dimension (surgical: 18.3±5.0 mm, nonsurgical: 15.7±4.3 mm, P=0.045) and TV:TP ratio (surgical: 0.55±0.15, nonsurgical: 0.47±0.12, P=0.036). Mechanical symptoms (surgical: 9/11, nonsurgical: 21/60, P=8.4×10^-6) and pain ≥1 month (surgical: 11/11, nonsurgical: 17/60, P=0.006) were found more often in surgical patients. Clinical and imaging criteria of mechanical symptoms and knee pain ≥1 month and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than 0.47 identified discoid menisci that developed a tear and/or required surgery with a sensitivity of 0.86 and specificity of 0.88.

CONCLUSION

Mechanical symptoms and knee pain ≥1 month, and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than or equal to 0.47, identified discoid menisci that would go on to tear and/or require surgery with a sensitivity and specificity of 0.86 and 0.88, respectively.

A Deep Learning System for Synthetic Knee Magnetic Resonance Imaging: Is Artificial Intelligence-Based Fat-Suppressed Imaging Feasible?

MATERIALS AND METHODS

This single-center study was approved by the institutional review board. Artificial intelligence-based FS MRI scans were created from non-FS images using a deep learning system with a modified convolutional neural network-based U-Net that used a training set of 25,920 images and validation set of 16,416 images. Three musculoskeletal radiologists reviewed 88 knee MR studies in 2 sessions, the original (proton density [PD] + FSPD) and the synthetic (PD + AFSMRI). Readers recorded AFSMRI quality (diagnostic/nondiagnostic) and the presence or absence of meniscal, ligament, and tendon tears; cartilage defects; and bone marrow abnormalities. Contrast-to-noise rate measurements were made among subcutaneous fat, fluid, bone marrow, cartilage, and muscle. The original MRI sequences were used as the reference standard to determine the diagnostic performance of AFSMRI (combined with the original PD sequence). This is a fully balanced study design, where all readers read all images the same number of times, which allowed the determination of the interchangeability of the original and synthetic protocols. Descriptive statistics, intermethod agreement, interobserver concordance, and interchangeability tests were applied. A P value less than 0.01 was considered statistically significant for the likelihood ratio testing, and P value less than 0.05 for all other statistical analyses.

RESULTS

Artificial intelligence-based FS MRI quality was rated as diagnostic (98.9% [87/88] to 100% [88/88], all readers). Diagnostic performance (sensitivity/specificity) of the synthetic protocol was high, for tears of the menisci (91% [71/78], 86% [84/98]), cruciate ligaments (92% [12/13], 98% [160/163]), collateral ligaments (80% [16/20], 100% [156/156]), and tendons (90% [9/10], 100% [166/166]). For cartilage defects and bone marrow abnormalities, the synthetic protocol offered an overall sensitivity/specificity of 77% (170/221)/93% (287/307) and 76% (95/125)/90% (443/491), respectively. Intermethod agreement ranged from moderate to substantial for almost all evaluated structures (menisci, cruciate ligaments, collateral ligaments, and bone marrow abnormalities). No significant difference was observed between methods for all structural abnormalities by all readers (P > 0.05), except for cartilage assessment. Interobserver agreement ranged from moderate to substantial for almost all evaluated structures. Original and synthetic protocols were interchangeable for the diagnosis of all evaluated structures. There was no significant difference for the common exact match proportions for all combinations (P > 0.01). The conspicuity of all tissues assessed through contrast-to-noise rate was higher on AFSMRI than on original FSPD images (P < 0.05).

CONCLUSIONS

Artificial intelligence-based FS MRI (3D AFSMRI) is feasible and offers a method for fast imaging, with similar detection rates for structural abnormalities of the knee, compared with original 3D MR sequences.

The Top 100 Most-Cited Articles on Arthroscopy: Most Popular Topic Is Rotator Cuff Rather Than Cartilage in the Last 5 Years

PURPOSE

To highlight the characteristics of the 100 most-cited articles on arthroscopy and provide the variation trend of citation rate among the top 25 articles in the past 9 years. We further analyzed the topics of interest in the past or currently.

METHODS

The Thomson ISI Web of Science database was used to identify arthroscopy-related articles that were published from 1950 to March 31, 2020. The 100 most-cited articles were selected for further analysis. In addition, author key words of the articles that published in the recent 5 years were further analyzed.

RESULTS

Mean of citations was 433.59 ± 400.73. The publication year ranged from 1980 to 2013. Most articles were focused on cartilage lesions and treatments (26%). A large proportion of articles were published in the 2000s (61%). Arthroscopy-the Journal of Arthroscopic and Related Surgery (23%) was the most popular journal. One half of the articles originated from the United States. The most prolific institution and first author were the Steadman Philippon Research Institute (5%) and Marc J. Philippon (4%), respectively. Most of the articles were Level IV evidence (33%). The citation rate increased by 131% from the previous top 25 articles published in 2011. A growth trend can be seen in the citation density over time. "Shoulder" (occurrences = 535) was the most used joint key word and "rotator cuff" (342) was the most used key word of research objective in the last 5 years, whereas "cartilage" only occurred 262 times.

CONCLUSIONS

Based on bibliometric analysis of the 100 most-cited articles on arthroscopy combined with network analysis of the whole articles that published in the recent 5 years, the topic of most interest in the recent 5 years was rotator cuff rather than cartilage. The number of citations among the 25 most-cited articles is growing rapidly and has at least doubled in size on average in the past 9 years. Citation density among the 100 most-cited articles on arthroscopy has seen a growth trend.

CLINICAL RELEVANCE

This article clarifies the characteristics of the 100 most-cited papers and provides guidance on the topics of interest in the past or currently as a roadmap for future research on arthroscopy.

Effect of High Tibial Osteotomy on the Distribution of Subchondral Bone Density Across the Proximal Tibial Articular Surface of the Knee With Medial Compartment Osteoarthritis

BACKGROUND

The effect of high tibial osteotomy (HTO) on the stress distribution across the knee joint is not completely understood. Subchondral bone density is considered to reflect the pattern of stress distribution across a joint surface.

PURPOSE

To assess the distribution of subchondral bone density across the proximal tibia in nonarthritic knees and in the knees of patients with osteoarthritis (OA) before and after HTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We retrospectively collected radiological and computed tomography data from 16 patients without OA (control group) and 17 patients with OA. Data from the OA group were collected before and 1.5 years after HTO. Subchondral bone density of the proximal tibia was assessed with computed tomography-osteoabsorptiometry. The locations and percentages represented by high-density areas (HDAs) on the articular surface were quantitatively analyzed.

RESULTS

The ratio of the HDA of the medial compartment to the total HDA (medial ratio) was significantly higher in the preoperative OA group (mean, 80.1%) than in the control group (61.3%) (P < .001). After HTO, the medial ratio decreased significantly to 75.1% (P = .035 in comparison with preoperative values) and was significantly correlated with the hip-knee-ankle angle in both groups: control (r = -0.551; P = .033) and OA (r = -0.528; P = .043). The change in medial ratio after HTO was significantly correlated with the change in hip-knee-ankle angle (r = 0.587; P = .035). In the medial compartment, the HDA in the most lateral region of 4 subregions increased after HTO, but that in 3 medial subregions decreased.

CONCLUSION

In this exploratory study, HTO shifted the HDA of the medial compartment of the proximal tibial articular surface toward the lateral compartment. In contrast, the HDA of the most lateral region of the medial compartment increased after HTO. This change in subchondral bone density may result from the change in stress distribution.

Meniscal pathology in children and adolescents

The menisci play a key role in knee biomechanics and long-term cartilage protection. Preserving the meniscus is thus a major functional consideration in children and adolescents. In normal menisci, lesions are traumatic in origin. They are often vertical, in the posterior segment, associated with anterior cruciate ligament tear. In abnormal menisci, lesions are much more specific to children, occurring atraumatically, mainly in discoid menisci. Clinical signs of traumatic meniscal lesion are minimal, and associated ligament involvement should be systematically screened for. In contrast, clinical findings are rich and specific in discoid malformative pathology, sometimes showing the typical "clunk" sign highly suggestive of a detachment. The complementary examination of choice is MRI. In children more than in adults, lesions need screening for in apparently normal menisci. This particularly concerns ramp lesions of the medial meniscus. It is important also to be aware of false signs, and notably linear hypersignal of vascular origin in the posterior segment of the medial meniscus. MRI is essential in determining type of tear and guiding surgery in discoid meniscal pathology. Indications for meniscal repair in children are maximal, even in lesions extending into the white zone, and the risk of failure needs to be assumed. All meniscal suture techniques - all-inside, in-out and out-in - need to be acquired. Meniscectomy, even partial, should be exceptional. Treatment of symptomatic discoid meniscus usually involves minimal central meniscoplasty and suture of the discovered lesion. Results of meniscal repair in children are generally very satisfactory, whatever the type or site of lesion. Vertical suture is to be preferred; suture failure is often only partial. In all, optimal treatment of meniscal pathology in children and adolescents requires perfect knowledge of pediatric specificities and above all mastery of repair techniques to restore meniscal tissue as fully as possible so as to conserve future knee function.

Should We Prefer Magnetic Resonance Imaging to Physical Examination in Meniscal Tears

The aim of this study was to compare the sensitivity, specificity, accuracy, positive and negative predictive values of magnetic resonance imaging (MRI), and clinical examination in the diagnosis of meniscus tears with the findings obtained from the knee joint arthroscopy. A retrospective study was made of 452 patients who underwent knee arthroscopy due to meniscus tears between 2012 and 2017. Physical examination was performed using the Thessaly's, McMurray's, and Joint line tenderness tests (JLTT). On preoperative MRI, medial meniscal tears were observed in 292 patients, lateral meniscal tears in 96 patients, and medial and lateral meniscal tears in 64 patients. According to the arthroscopy results, 284 patients had medial meniscal tears, 108 patients had lateral meniscal tears, and 60 patients had medial and lateral meniscal tears. Sensitivity and specificity of the JLTT was determined as 93 and 86% respectively for medial meniscal tears and 94 and 89% for lateral meniscal tears. The McMurray's test was 60% sensitive, 68% specific for medial meniscal tears (MMT), and 73% sensitive and 68% specific for lateral meniscus tears (LMT). The Thessaly's test was 93% sensitive and 87% specific for medial meniscal tears; and 94% sensitive and 88% specific for LMT. Compared with the arthroscopic findings, MRI was observed to have sensitivity of 94% for MMT and 84% for LMT. For specificity, the values were 89% for MMT and 91% for LMT. Accuracy was 89% for MMT and 86% for LMT. In comparison with the arthroscopic findings, the triple test was determined to have sensitivity of 92% for MMT and 89% for LMT. The specificity was 88% for MMT and 91% for LMT. The results of this study showed that a combination of selected physical examination methods is as sensitive as MRI in the diagnosis of meniscus tears.

Results of meniscal injuries repair using different arthroscopic techniques

AIM

Evaluation of clinical and radiological outcomes following meniscal repair using different arthroscopic techniques for all meniscal tears amenable for repair.

METHODS

Sixty-one patients were involved in a prospective study; all cases presented with meniscal tears underwent arthroscopic meniscal repair from December 2016 to December 2017. Outcomes involved the site of tear, the repair technique, and associated injuries. The International Knee Documentation Committee Score (IKDC) and Tegner Lysholm Knee Score were used to analyze the clinical and functional outcomes postoperatively.

RESULTS

Of the 61 patients, 50 patients (81.9%) had meniscal tear associated with isolated ligamentous ACL injury, 6 cases had corrective osteotomy with ACL reconstruction to correct concomitant genu varus, 2 cases (3.3%) had meniscal tear associated with isolated ligamentous PCL injury, and 9 patients (14.8%) presented with isolated meniscal tear; IKDC was preoperatively (44.52 ± 8.79), postoperatively at 6 months (90.97 ± 6.75) and at 12 months (92.27 ± 2.68) with P-value (0.001). Tegner Lysholm score was preoperatively (52.16 ± 12.22), postoperatively at 6 months (88.03 ± 6.84) and at 12 months (93.26 ± 2.95) with P-value (0.001). Fifty eight patients (95.1%) had no postoperative symptoms at 6 and 12 months' follow-up. The remaining 3 cases (4.9%) underwent partial meniscectomy due to persistent postoperative clinical symptoms with no signs of healing in MRI.

CONCLUSIONS

Our study concluded that arthroscopic meniscal repair is an effective way in the management of meniscal tears regarding clinical and functional outcomes.

The modified cross-suture technique for unilateral pulled-out anchor during all-inside meniscal repair

Background

Meniscal repair has received increasing attention, but for inexperienced doctors, unilateral suture anchor pulling out may occur during all-inside meniscal repair, and the treatment outcome may be affected. When the errors happened intraoperatively, how to minimize the loss under guaranteeing of treatment effectiveness is a topic worth studying.

Purpose

To explore the practicability and effectiveness of the modified cross-suture method for arthroscopic remediation of unilateral suture anchor pulling out of an all-inside meniscal repair system.

Methods

From May 2014 to May 2017, 28 patients diagnosed with injuries of the meniscus and anterior cruciate ligaments (ACL) from the First Department of Orthopaedics of the Second Affiliated Hospital of Xi’an Jiaotong University were enrolled in the study as the observation group, including 18 males and 10 females with an average age of 25.5 ± 2.3 years (range 18–42 years). All patients underwent ACL reconstruction concurrently. All meniscus injuries were repaired with an all-inside meniscal repair technique, and 1–3 needles of unilateral suture anchor pulling out occurred intraoperatively. The modified cross-suture method was used to remedy the error of anchor pulling out and to eventually complete an effective repair. Another 30 patients who underwent ACL reconstruction and all-inside meniscal concurrently without unilateral suture anchor pulling out, including 20 males and 10 females with an average age of 26.3 ± 1.9 years (range 19–45 years), were enrolled as the control group. During postoperative follow-up, range of motion, Lachman test and pivot shift test were performed during the physical examination. The clinical healing of the meniscus was evaluated according to the Barrett standard. The meniscus healing status was also confirmed with magnetic resonance imaging (MRI). The function of the knee joint was evaluated according to the IKDC, Lysholm and Tegner scores.

Results

Twenty-five patients in the observation group and 28 patients in the control group completed the follow-up, with an average follow-up of 18.4 ± 5.2 months. All operations were performed by the same surgeon. At the follow-up 1 year after the operation, the average knee ROM of the two groups was 125.2 ± 4.3 degrees and 124.7 ± 3.8 degrees, the clinical healing rate of the meniscus of the two groups was 92.0% (23/25) and 92.9% (26/28), the MRI healing rate of the menniscus of the two groups was 72.0% (18/25) and 71.4% (20/28), and the IKDC, Lysholm and Tegner scores of the two groups were 90.52 ± 2.8, 89.17 ± 3.1, and 6.81 ± 1.7 and 91.42 ± 1.9, 90.32 ± 3.4, and 7.02 ± 1.4, respectively. The differences were not statistically significant (P > 0.05).

Conclusions

The modified cross-suture method is practicable and effective for arthroscopic remediation of unilateral suture anchor pulling out in an all-inside meniscal repair system.

Development of osteoarthritis in patients with degenerative meniscal tears treated with exercise therapy or surgery: a randomized controlled trial

OBJECTIVE

To evaluate progression of individual radiographic features 5 years following exercise therapy or arthroscopic partial meniscectomy as treatment for degenerative meniscal tear.

DESIGN

Randomized controlled trial including 140 adults, aged 35-60 years, with a magnetic resonance image verified degenerative meniscal tear, and 96% without definite radiographic knee osteoarthritis. Participants were randomized to either 12-weeks of supervised exercise therapy or arthroscopic partial meniscectomy. The primary outcome was between-group difference in progression of tibiofemoral joint space narrowing and marginal osteophytes at 5 years, assessed semi-quantitatively by the OARSI atlas. Secondary outcomes included incidence of radiographic knee osteoarthritis and symptomatic knee osteoarthritis, medial tibiofemoral fixed joint space width (quantitatively assessed), and patient-reported outcome measures. Statistical analyses were performed using a full analysis set. Per protocol and as treated analysis were also performed.

RESULTS

The risk ratios (95% CI) for progression of semi-quantitatively assessed joint space narrowing and medial and lateral osteophytes for the surgery group were 0.89 (0.55-1.44), 1.15 (0.79-1.68) and 0.77 (0.42-1.42), respectively, compared to the exercise therapy group. In secondary outcomes (full-set analysis) no statistically significant between-group differences were found.

CONCLUSION

The study was inconclusive with respect to potential differences in progression of individual radiographic features after surgical and non-surgical treatment for degenerative meniscal tear. Further, we found no strong evidence in support of differences in development of incident radiographic knee osteoarthritis or patient-reported outcomes between exercise therapy and arthroscopic partial meniscectomy.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT01002794).

The prevalence of Baker cyst in relation to the arrangement pattern between the medial head of gastrocnemius tendon and the semimembranosus tendon

PURPOSE

The purpose of this study was to investigate whether Baker cyst (BC) was related to the specific arrangement of the medial head of gastrocnemius tendon (MHGT) and the semimembranosus tendon (SMT).

MATERIALS AND METHODS

Patients who underwent knee MRI with "Baker cyst" in PACS from August 2017 to February 2018 were included in this study. Patients who did not have BC in a knee MRI performed during the same period were included in the control group. A total 210 patients were selected for inclusion in this study. For the imaging analysis, the arrangement pattern between MHGT and SMT was classified into three types: type 1, concave; type 2, flat; and type 3, convex. When imaging analysis was performed, the amount of effusion, the presence of osteoarthritis, and major ligament and meniscal tears were also described. Univariate and multivariate logistic regression analyses were performed. Statistical significance was considered at p < 0.05.

RESULTS

The frequency of types 1, 2, and 3 was statistically significant depending on the presence or absence of BC (p < 0.001). The frequency of type 3 was the highest in the presence of BC, while that of type 1 was the highest in the absence of BC. BC was more common in type 2 (OR = 2.54; 95% CI = 1.27-5.07) and type 3 (OR = 4.09; 95% CI = 1.88-8.89).

CONCLUSION

BC is more likely to occur in patients with SMT having a convex shape for MHGT.

KEY POINTS

• Based on axial image of MRI only, one can predict which patients are morphologically more prone to develop a Baker cyst. • On axial images of MRI, Baker cyst is more likely to occur in patients with semimembranosus tendon having a convex shape for medial head of gastrocnemius tendon. • Baker cyst is not associated with the amount of effusion, OA, or internal derangement.

The accuracy of magnetic resonance imaging diagnosis of non-osseous knee injury at Steve Biko Academic Hospital

Background

Preoperative magnetic resonance imaging (MRI) has internationally been proven to reduce unnecessary knee arthroscopies and assist with surgical planning. This has the advantage of avoiding unnecessary surgery and the associated anaesthetic risk, as well as reducing costs. No data were found in the recently published literature assessing the accuracy of MRI interpretation of knee ligament injury in the public sector locally.

Objectives

This pilot study aimed to determine the accuracy of MRI in detecting non-osseous knee injury in a resource-limited tertiary-level academic hospital in Pretoria, South Africa, compared to the gold standard arthroscopy findings.

Method

This was an exploratory retrospective analysis of 39 patients who had MRI and arthroscopy at Steve Biko Academic Hospital (SBAH). True positive, true negative, false positive and false negative results were extrapolated from findings in both modalities and translated into sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each structure.

Results

Negative predictive values were recorded as 97%, 81%, 90% and 100% (anterior cruciate ligament [ACL], medial meniscus [MM], lateral meniscus [LM] and posterior cruciate ligament [PCL], respectively), which were comparative to recently published international literature. The PPV results were lower than those previously evaluated at 55%, 58%, 55% and not applicable. The sensitivities and specificities of the ligaments were 83%, 58%, 83% and not applicable; and 87%, 81%, 70% and not applicable, respectively.

Conclusion

Magnetic resonance imaging was found to be sensitive and specific, with a high NPV noted in all structures evaluated. Negative results can therefore be used to avoid unnecessary surgery to the benefit of the patient and state. The study reiterates that high accuracy can be obtained from MRI on a 1.5-tesla non-dedicated scanner, with interpretation by generalist radiologists.

Assessment of 3-T MRI using susceptibility-weighted imaging to detect and evaluate intra- or periarticular blood metabolites and meniscal tears of the knee

Purpose

The purpose of this study was to assess the suitability of susceptibility-weighted imaging (SWI) sequences using the 3T MRI-unit for assessment of potential intraarticular pathologies in patients with acute and chronic torsion trauma of the knee joint.

Material and methods

Sixty-three patients with subacute and chronic rotary knee joint trauma of either the left or right knee were studied using an Achieva MRI 3T device (Philips, Amsterdam, Netherlands). Ground truth was set by two expert radiologists with seven and 10 years of experience in musculoskeletal imaging. Readings were performed separately for meniscus and joint space including synovia, ligaments, and periarticular soft tissue. Haemorrhage was defined as any lesion that was either T1 or SWI positive, without proton density (PD)-hypointensity (calcification). A lesion was defined as any pathology/variant with any signal positivity of either T1, PD, or SWI.

Results

A total of 63 patients were included (F : M = 22 : 41). The median age of the cohort was 29 years (range 13 to 71 years). Thirty-nine patients showed a meniscal tear, and only three of them (7.7%) demonstrated a meniscal haemorrhage. A total of 18 patients suffered from a periarticular injury, and 16 patients (88.9%) demonstrated a concomitant periarticular haemorrhage.

Conclusions

These data suggest that SWI can be used for the diagnosis of intra- or periarticular blood metabolites because their potential have an impact on mechanical conflict with the surface of the knee joints, in particular the cartilage and their effect on malacic lesions, but it performs poorly in the detection of meniscal pathologies.

Medial meniscal extrusion and spontaneous osteonecrosis of the knee

PURPOSE

Causes of spontaneous osteonecrosis of the knee (SONK) have not been clearly elucidated. This study investigated the relationship between medial meniscal extrusion and SONK.

METHODS

We reviewed 108 SONK knees and determined their Aglietti stage. Meniscal extrusion is defined when it extends beyond the medial margin of tibial plateau and osteophytes are excluded for determining the margin. Both absolute extrusion (AE) and relative percentage of extrusion (RPE) were measured, and meniscal tear patterns were evaluated in the early stages of SONK (I and II).

RESULTS

All knees had meniscal extrusion. Stage I was detected in 39 knees; II, in 23; III, in 16; IV, in 18; and V, in 12. The mean AE and RPE were 4.2 mm and 42% in stage I, 5.0 mm and 52% in stage II, 6.8 mm and 71% in stage III, 7.0 mm and 69% in stage IV, and 7.8 mm and 80% in stage V, respectively. The knees in the early stages showed less AE and RPE than those in late stages IV (p < 0.05) and V (p < 0.01). Additionally, the level of AE (ρ = 0.63, p < 0.0001) and RPE (ρ = 0.58, p < 0.0001) correlated with the SONK stage. Of knees with early-stage SONK, 12 knees had no tear, 26 had horizontal tears, 1 had longitudinal tear, 6 had degenerative tears, 2 had radial tears, 1 had complex tear, and 14 had root tears. Neither AE nor RPE differed significantly among tear patterns.

CONCLUSIONS

Meniscal extrusion was recognized even in early stages, with a significant correlation between the SONK stage and extrusion. Although the most frequent tear pattern in early-stage SONK was horizontal tear, 12 knees had meniscal extrusion with no tears. Therefore, meniscal extrusion, which indicates meniscal dysfunction, may be a cause of SONK and be related with the developmental stage of SONK.

Complex Tears, Extrusion, and Larger Excision Are Prognostic Factors for Worse Outcomes 1 and 2 Years After Arthroscopic Partial Meniscectomy for Degenerative Meniscal Tears: A Secondary Explorative Study of the Surgically Treated Group From the Odense-Oslo Meniscectomy Versus Exercise (OMEX) Trial

BACKGROUND

Few studies have examined morphological findings from preoperative magnetic resonance imaging (MRI) and arthroscopic findings as prognostic factors for outcomes 1 and 2 years after arthroscopic partial meniscectomy (APM).

PURPOSE/HYPOTHESIS

The purpose was to evaluate prognostic factors of preoperative findings from MRI and arthroscopic evaluation on lower extremity performance at 1 year and patient-reported outcomes at 1 to 2 years after APM. The hypothesis was that medial compartment abnormalities would be prognostic for 1- and 2-year functional outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This secondary analysis from the OMEX (Odense-Oslo Meniscectomy Versus Exercise) trial included 40 patients treated surgically. Regression analyses with adjustments for age, sex, and body mass index explored associations between MRI findings (tear complexity and extrusion), arthroscopic findings (tear length, cartilage injury, and amount of excised meniscal tissue), and the following: lower extremity performance tests and thigh muscle strength at 1 year and the 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales at 1 and 2 years.

RESULTS

A complex meniscal tear was a significant and clinically relevant prognostic factor for worse KOOS Symptoms subscores at 2 years (mean, 14.1 points [95% CI, 6.1-22.2]). Meniscal extrusion of at least 11%, 25%, and 20% were significant and clinically relevant prognostic factors for worse KOOS Activities of Daily Living (ADL) subscores at 1 year and worse KOOS Sports and Recreation (Sports/Rec) subscores at 1 and 2 years, respectively. Tear lengths of at least 7.0 mm, 6.7 mm, and 6.5 mm were significant and clinically relevant prognostic factors for better KOOS Symptoms subscores at 1 year and better KOOS Sports/Rec subscores at 1 and 2 years, respectively. A cartilage injury in the medial compartment was a significant and clinically relevant prognostic factor for worse KOOS ADL and Quality of Life (QoL) subscores at 2 years (mean, 10.4 and 19.4 points, respectively [95% CI, 3.4-17.4 and 7.7-31.1, respectively]). More than 20% meniscal tissue excised was a significant and clinically relevant prognostic factor for worse KOOS Pain, Symptoms, ADL, and Sports/Rec subscores at 1 and 2 years (mean, 8.9-41.5 points [95% CI, 2.2-15.5 to 21.0-62.0]) and worse KOOS QoL subscores at 2 years (mean, 25.3 points [95% CI, 13.6-37.0]).

CONCLUSION

Complex meniscal tears, larger extrusion, cartilage injuries, and larger meniscal excision were significant and clinically relevant prognostic factors for worse outcomes 1 and 2 years after APM.

REGISTRATION

NCT01002794 (ClinicalTrials.gov identifier).

Outcomes and Patient Satisfaction With Arthroscopic Partial Meniscectomy for Degenerative and Traumatic Tears in Middle-Aged Patients With No or Mild Osteoarthritis

BACKGROUND

There is controversy about the benefit of arthroscopic partial meniscectomy (APM) for degenerative lesions in middle-aged patients.

PURPOSE

To compare satisfaction with APM between middle-aged patients with no or mild knee osteoarthritis (OA) and a degenerative meniscal tear and those with a traumatic tear.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A comparative prospective study at 5 years of middle-aged patients (45-60 years old) with no or mild OA undergoing APM for degenerative (n = 115) or traumatic (n = 143) tears was conducted. Patient satisfaction was measured by a 5-point Likert scale and functional outcomes by the Knee injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Univariate and multivariate regression analyses were used to identify factors correlating with patient-reported satisfaction at 5 years postoperatively.

RESULTS

Baseline patient characteristics were not different between groups. At the 5-year evaluation, the satisfaction rate in the traumatic and degenerative groups was 68.5% versus 71.3%, respectively (P = .365). Patient satisfaction was significantly associated with functional outcomes (r = 0.69; P = .024). In the degenerative group, 43 patients (37.4%) had OA progression to Kellgren-Lawrence (K-L) grade 2 or 3, but only 24 patients (20.8%) had a symptomatic knee at final follow-up. Multivariate regression analysis for patient dissatisfaction at 5-year follow-up showed the following significant independent factors: female sex (odds ratio [OR], 1.6 [95% CI, 1.1-2.3]; P = .018), body mass index >30 kg/m² (OR, 2.6 [95% CI, 1.7-4.9]; P = .035), lateral meniscal tears (OR, 0.6 [95% CI, 0.1-0.9]; P = .039), and OA progression to K-L grade ≥2 at final follow-up (OR, 1.4 [95% CI, 1.2-2.6]; P = .014). At the final evaluation, there were no significant differences between groups in pain scores (P = .648), WOMAC scores (P = .083), or KOOS-4 scores (P = .187). Likewise, there were no significant differences in the KOOS subscores for Pain (P = .144), Symptoms (P = .097), or Sports/Recreation (P = .150). Although the degenerative group had significantly higher subscores for Activities of Daily Living (P = .001) and Quality of Life (P = .004), the differences were considered not clinically meaningful.

CONCLUSION

There were no meaningful differences in patient satisfaction or clinical outcomes between patients with traumatic and degenerative tears and no or mild OA. Predictors of dissatisfaction with APM were female sex, obesity, and lateral meniscal tears. Our findings suggested that APM was an effective medium-term option to relieve pain and recover function in middle-aged patients with degenerative meniscal tears, without obvious OA, and with failed prior physical therapy.

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.

The International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine classification of knee meniscus tears: three-dimensional MRI and arthroscopy correlation

OBJECTIVES

To introduce MRI-based International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification system of meniscal tears and correlate it to the surgical findings from arthroscopy. We hypothesized that the ISAKOS classification will provide good inter-modality and inter-rater reliability for use in the routine clinical practice of radiologists and orthopedic surgeons.

METHODS

In this HIPAA-compliant cross-sectional study, there were 44 meniscus tears in 39 patients (26 males, 16 females). Consecutive arthroscopy-proven meniscal tears (March 2017 to December 2017) were evaluated by two board-certified musculoskeletal radiologists using isotropic three-dimensional (3D) MRI user-defined reconstructions. The surgically validated ISAKOS classification of meniscal tears was used to describe medial meniscus (MM) and lateral meniscus (LM) tears. Prevalence-adjusted bias-adjusted kappa (PABAK) and conventional kappa, and paired t test and intra-class correlation coefficient (ICC) were calculated for categorical and numerical variables, respectively.

RESULTS

For the MM, the PABAK for location, depth, length (ICC), pattern, quality of meniscus tissue, and zone was 0.7-1, 0.65, 0.57, 0.67, 0.78, and 0.39-0.7, respectively. For the LM, the PABAK for location, depth, length (ICC), pattern, quality of meniscus tissue, zone, and central to popliteus hiatus was 0.57-0.95, 0.57, 0.74, 0.93, 0.38, 0.52-0.67, and 0.48, respectively. The mean tear lengths were larger on MRI than on arthroscopy (mean difference MM 9.74 mm (6.66 mm, 12.81 mm; p < 0.001), mean difference LM 4.04 mm (0.31 mm, 7.76 mm; p = 0.034)).

CONCLUSIONS

The ISAKOS classification of meniscal tears on 3D MRI provides mostly moderate agreement, which was similar to the agreement at arthroscopy.

KEY POINTS

• There is a fair to good inter-method correlation in most categories of ISAKOS meniscus tear classification. • The tear lengths are significantly larger on MRI than on arthroscopy. • The inter-reader correlation on 3D MRI is moderate to excellent, with the exception of lateral meniscus tear patterns.

Meniscal repair associated with a partial meniscectomy for treating complex horizontal cleavage tears in young patients may lead to excellent long-term outcomes

INTRODUCTION

While open repair of horizontal meniscal tears in young active patients has shown good results at mid- and long-term follow-up, complex horizontal tears (cleavage associated with meniscal flaps) are often treated by arthroscopic subtotal meniscectomy. The aim of this study was to evaluate long-term outcomes after arthroscopic removal of meniscal flaps associated with an open meniscal repair for treating complex lesions in young active patients. The hypothesis was that this salvage procedure would be efficient in such rare cases.

METHODS

Fourteen patients underwent an arthroscopic partial meniscectomy associated with an open meniscal repair to treat a painful complex horizontal meniscal cleavage between 2005 and 2010. There were two females and 12 males with a median age of 28.4 years (range 15-48 years). Patients were assessed by KOOS and IKDC scores, return to sport and the need for a secondary meniscectomy.

RESULTS

Thirty patients were evaluated at a median follow-up of 8.5 years (range 7-12 years). One patient required revision of a partial meniscectomy and one other a meniscal replacement (15% failure rate). All other patients showed improvement with regard to their symptoms and returned to sports, ten (91%) of them at the same level. The mean IKDC subjective score was 86.1 (± 10.9). The mean KOOS scores were: pain 91.4 (± 7.5), symptoms 91.4 (± 10.2), daily activity 97.1 (± 4), sports 84.4 (± 20.7) and quality of life 84 (± 14.2). For six patients, scores at median follow-up of 2.6 years were available and compared to newly obtained data. IKDC score at 8.6 years follow-up was not significantly different. KOOS scores for daily activity and sports were maintained.

CONCLUSIONS

Even in the presence of a complex lesion, horizontal cleavage can be repaired in young patients with good subjective and objective outcomes and a low rate of long-term failure as with other meniscal lesions in young active patients.

LEVEL OF EVIDENCE

IV.

Role of low field MRI in detecting knee lesions

Objective The aim of this work is to evaluate the diagnostic accuracy of 0.3T sectoral MR imaging, compared with arthroscopy, for meniscal, cruciate ligaments and chondral knee lesions. Materials and Methods We conducted a retrospective study analyzing all the consecutive knees subjected to arthroscopy at our institution between January 2014 and June 2017 and preceded within 3 months by knee MR examination at our institution with 0.3 T equipment. Patients with history of a new trauma in the time interval between MR exam and arthroscopy were excluded from the study. Two independent experienced radiologists evaluated in double blind the MR findings of menisci, cruciate ligaments and articular cartilage. Both radiological findings were independently compared with those of the arthroscopic report considered as gold standard. For each of the examined targets we calculated the following parameters: sensitivity, specificity, accuracy, positive and negative predictive value; interobserver concordance statistically calculated using Cohen's Kappa test. Results 214 knees (95R/119L) of 214 patients (143M/71F) aged from 18 to 72 years (mean 44) were included and analyzed. We found a good diagnostic accuracy of the low field MR in identifying the injuries of the menisci (93%) and the crossed ligaments (96%), but a lower accuracy for the articular cartilage (85%). Sensitivity resulted 90% for menisci, 73% for ligaments and 58% for cartilage. Specificity was 91% for menisci, 97% for ligaments and 92% for cartilage. Inter-observer concordance resulted to be excellent for cruciate ligaments (K of Cohen's test = 0.832), good (K = 0.768) for menisci, modest to moderate for articular cartilage (K from 0.236 to 0.389) with worse concordance for tibial cartilage. Conclusions Low-field MR sectoral device with dedicated joint equipment confirms its diagnostic reliability for the evaluation of meniscal and cruciate ligaments lesions but is weak in evaluating low grade chondral lesions.

Comparison of T2* mapping between regular echo time and ultrashort echo time with 3D cones at 3 tesla for knee meniscus

The objectives of this study were to compare the ultrashort T2* relaxation time with the T2* relaxation time using the 3 dimensional (3D) cones sequence in 3 groups of patients with normal, degenerated, and torn knee menisci, and to demonstrate the additional effect of the ultrashort echo time (UTE) signal intensity.Following institutional review board approval, 42 knee magnetic resonance imaging (MRI) scans of 42 patients who presented with knee pain and underwent knee MRIs, with the 3D Cones of UTE sequence (minimum TEs: 32 μs) and a 3T MRI scanner (Discovery 750, GE Healthcare, Waukesha, WI), were analyzed. The enrolled patients were classified into 3 subgroups:normal meniscus on conventional MRI, with no positive meniscus-related physical examination in medical records;meniscal degeneration with signal changes on conventional MRI; andmeniscal tear.For the quantitative assessment, the mean values inside user-drawn regions of interest (ROIs) of the medial menisci were drawn on UTE T2* map and T2* map. For statistical analyses, 1-way analysis of variance (ANOVA) with post-hoc analysis using the Tukey HSD test was conducted to compare groups, and effect size was used to compare the discrimination power.The ultrashort T2* relaxation times were higher in patients with meniscal tear than in those with normal and degeneration groups (P <.05, respectively) whereas T2* relaxation times were not statistically significantly different. The ultrashort T2* relaxation times showed higher effect sizes than the T2* times between tear and normal/degeneration.The ultrashort T2* relaxation times showed better delineation of meniscal degeneration or tears than T2* relaxation times. The ultrashort T2* relaxation times could be more sensitive at differentiating between normal and pathologic meniscal conditions in patients.

Clinical value of pointwise encoding time reduction with radial acquisition (PETRA) MR sequence in assessing internal derangement of knee

PURPOSE

The purpose was to evaluate the clinical value of PETRA sequence for the diagnosis of internal derangement of the knee.

MATERIALS AND METHODS

The major structures of the knee in 34 patients were evaluated and compared among conventional MRI findings, PETRA images, and arthroscopic findings.

RESULTS

The specificities of PETRA with 2D FSE sequence were higher for meniscal lesions than those obtained when using 2D FSE alone.

CONCLUSION

Using PETRA images along with conventional 2D FSE images can increase the accuracy of assessing internal derangements of the knee and, specifically, meniscal lesions.

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.