Diagnostic IRM des lambeaux méniscaux médiaux déplacés le long du ligament tibial collatéral

The "sleeper's sign" is valid and suggestive of a medial sub-meniscal flap tear

PURPOSE

To describe, evaluate and validate the diagnostic performance of a new clinical sign, the sleeper's sign, for the diagnosis of a medial submeniscal flap tear (MSMFT).

METHODS

This retrospective single-center series included patients aged 18-55 years old who underwent arthroscopic treatment in 2013-2015 for a medial meniscal tear. This study was performed according to STARD (standards for reporting of diagnostic accuracy) guidelines, and the reference test was a peroperative diagnosis of a MSMFT. The preoperative consultation reports were all analyzed to search for the sleeper's sign, defined as night time medial tibiofemoral pain when the patient is in the fetal position with both knees in contact and no pain during daytime activities.

RESULTS

Three-hundred and ten patients responded to the study criteria, mean age 41.7 ± 9.7 years old. The sleeper's sign was identified in 39 (12.6%) patients and a MSMFT was confirmed during arthroscopy in 47 (15.2%) cases, with significant agreement between this sign, arthroscopy (kappa = 0.78, p = 10^-4) and MR-imaging (kappa = 0.72, p < 0.0001). The performance parameters of the sleeper's sign were: sensitivity 74.5 ± 12.5%, specificity 98.5 ± 1.6%, Youden index 0.73 and accuracy 96.9%. MR imaging was found to be more sensitive (91.5 ± 8%). Multivariate analysis identified the sleeper's sign as a risk factor of MSMFT during arthroscopy: OR 131.9 CI 95% [26.9-646.2], p < 0.0001 and a bone edema next to the flap tear on MR-imaging: OR 13, CI 95% [1.9-7.1], p = 0.008.

CONCLUSION

The "sleeper's sign" is a new, valid, highly specific clinical sign for the diagnosis of a medial submeniscal flap tear. MRI was found to be more sensitive than the sleeper's sign.

LEVEL OF EVIDENCE

II.

The Meniscal Grammar Signs: Comma and Apostrophe Signs for Characterization of a Displaced Fragment in the Meniscal Recess

Vertical flap tears, or parrot beak flap tears, are oblique tears of the meniscus thought to originate as a central radial tear and propagate longitudinally towards the periphery, generating a partially detached unstable fragment that can subsequently displace into the meniscal recess. Although magnetic resonance imaging (MRI) is frequently used to diagnose and characterize meniscus pathology, imaging findings for displaced flap tears are not well described in the literature. The recently published meniscal comma sign describes inferior displacement of a meniscus flap tear into the meniscotibial recess that, when seen on MRI, resembles a comma. In the present article, we define the meniscal apostrophe sign, characterized by superior displacement of a meniscus flap tear into the meniscofemoral recess found on MRI. Displaced fragments in the meniscal recess are crucial to identify, as they often result in significant pain and mechanical symptoms related to tenting of the deep medial collateral ligament, which responds poorly to nonoperative treatment. Misdiagnosis of these unstable flap tears as degenerative meniscus extrusion or isolated progression of osteoarthritis can lead to a delay in treatment.

Common Mistakes and Pitfalls in Magnetic Resonance Imaging of the Knee

This pictorial review presents an overview of common interpretation errors and pitfalls in magnetic resonance imaging (MRI) of the knee. Instead of being exhaustive, we will emphasize those pitfalls that are most commonly encountered by young residents or less experienced radiologists.

MR imaging characteristics and clinical symptoms related to displaced meniscal flap tears

OBJECTIVES

The purpose of our study was (1) to analyze the flap tear location, direction of displacement and size on magnetic resonance (MR) imaging, (2) to describe associated knee abnormalities including presence of effusion, synovitis, bone marrow edema pattern or ligamentous tear, and (3) to assess clinical findings found with flap tears, including the pain score, and determine differences between operative and nonoperative groups.

MATERIALS AND METHODS

A retrospective radiology database search over the last 3 years identified 238 patients with flap tears, of which ultimately 58 with isolated flap tears were included after exclusion of patients with other significant knee internal derangement, severe degenerative change or prior surgery. MR studies of the knee were analyzed by two radiologists. Imaging characteristics were correlated with associated knee abnormalities and clinical findings. Statistical analysis employed linear and logistic regression models. Inter- and intrareader reliability was calculated.

RESULTS

The medial meniscus was the most common site of flap tears (52/60, 87 %), with inferior displacement (47/60, 78 %). The degree of tibial cartilage loss had a positive correlation with the visual analog pain scale (p = 0.03). Patients who underwent arthroscopy were younger than those who did not (p = 0.01) and more likely to have a positive clinical McMurray test (p = 0.01).

CONCLUSION

Medially and inferiorly displaced flap tears are the most common tear pattern. Those undergoing arthroscopy are more likely to have positive meniscal signs on clinical examination. A greater degree of cartilage loss involving the tibia on MR imaging was associated with increasing visual analog pain scores.

Histological scoring systems for tissue-engineered, ex vivo and degenerative meniscus

PURPOSE

Because its function is strictly related to the quality of meniscal tissue, one of the most important outcome measures for the evaluation of meniscal repair effectiveness is the assessment of histological features. Data on the validation and application of the histological scoring systems in research settings and specific fields of meniscal disorders are lacking. The available histological scoring systems to assess meniscal tissue were systematically evaluated.

METHODS

Histological scoring systems for the analysis of degenerative meniscal changes, ex vivo and tissue-engineered meniscal repair were reviewed. Furthermore, the validity and applicability of the scoring systems were assessed.

RESULTS

The Copenhaver classification and Mankin score have been modified to classify the degeneration of collagen bundles in the meniscal structure. The Pauli score seems to be a comprehensive and simple scoring system for the evaluation of both macroscopic and histologic meniscal changes related to ageing and osteoarthritic degeneration. The Zhang score may be used for ex vivo gene therapy in meniscus healing. The Ishida score seems to be the most adequate for the evaluation of tissue-engineered meniscal repair.

CONCLUSION

Although several histological scoring systems are available to assess meniscal structure, only few of them have been validated for specific application in research settings. Validated scores are required to provide a standardized data collection to allow the comparison of results of different research groups. Further experimental and clinical studies are needed to find a comprehensive and validated histological scoring system in the field of meniscus repair.

LEVEL OF EVIDENCE

Systematic review of Level III studies, Level III.