(ii) Meniscal tears

Pediatric meniscal surgery in Italy: A 10-year epidemiological nationwide registry study

Purpose

Over the last two decades the incidence of meniscal injuries has grown amongst the pediatric population predominantly due to greater involvement in sporting activities. The treatment and the natural history represent a socioeconomic burden for healthcare systems. This study demonstrates the epidemiology of meniscal tears treated surgically in Italy from 2010 to 2019 in a population up to 18 years.

Methods

Data was collected from the National Archive of Hospital Discharges. ICD9-CM classification was used to select surgically treated meniscal injuries. Concomitant treatment of associated lesions were excluded. Data on the national population was retrieved from the Italian National Institute for Statistics (ISTAT). Statistical analyses were performed.

Results

17,449 isolated meniscal tears were surgically treated with a mean incidence of 20.6 per 100.000 in the Italian population aged up to 18 from 2010 to 2019. The mean age of patients was 15.85 with 89 % aged 14 or older. 30 % of the population was female. The incidence of medial meniscal surgery was higher than for the lateral meniscus. A declining trend in surgical incidence was observed. The mean hospitalization time was 1.53 days.

Conclusions

Our study reveals a reduction in the total number of surgeries performed over the time frame and a significant rise in the incidence of meniscal lesions in pediatric patient above at the age of 13, especially in males. Despite a worldwide shift towards meniscal preservation, this trend is not evident in Italy as the current ICD9-CM classification does not differentiate between meniscectomy and meniscal repair, although an overall reduction in surgery may imply better management.

Study design

Cohort study; Level of evidence III.

Prediction model for tibial plateau fracture combined with meniscus injury

Purpose

To investigate a prediction model of meniscus injury in patients with tibial plateau fracture.

Methods

This retrospective study enrolled patients with tibial plateau fractures who were treated in the Third Hospital of Hebei Medical University from January 1, 2015, to June 30, 2022. Patients were divided into a development cohort and a validation cohort based on the time-lapse validation method. Patients in each cohort were divided into a group with meniscus injury and a group without meniscus injury. Statistical analysis with Student's t-test for continuous variables and chi square test for categorical variables was performed for patients with and without meniscus injury in the development cohort. Multivariate logistic regression analysis was used to screen the risk factors of tibial plateau combined with meniscal injury, and a clinical prediction model was constructed. Model performance was measured by examining discrimination (Harrell's C-index), calibration (calibration plots), and utility [decision analysis curves (DCA)]. The model was validated internally using bootstrapping and externally by calculating their performance in a validation cohort.

Results

Five hundred patients (313 [62.6%] males, 187 [37.4%] females) with a mean age of 47.7 ± 13.8 years were eligible and were divided into development (n = 262) and validation (n = 238) cohorts. A total of 284 patients had meniscus injury, including 136 in the development cohort and 148 in the validation cohort We identified high-energy injuries as a risk factor (OR = 1.969, 95%CI 1.131-3.427). Compared with blood type A, patients with blood type B were more likely to experience tibial plateau fracture with meniscus injury (OR = 2.967, 95%CI 1.531-5.748), and office work was a protective factor (OR = 0.279, 95%CI 0.126-0.618). The C-index of the overall survival model was 0.687 (95% CI, 0.623-0.751). Similar C-indices were obtained for external validation [0.700(0.631-0.768)] and internal validation [0.639 (0.638-0.643)]. The model was adequately calibrated and its predictions correlated with the observed outcomes. The DCA curve showed that the model had the best clinical validity when the threshold probability was 0.40 and 0.82.

Conclusions

Patients with blood type B and high-energy injuries are more likely to have meniscal injury. This may help in clinical trial design and individual clinical decision-making.

Preparation of hybrid meniscal constructs using hydrogels and acellular matrices

To search for a suitable meniscus repair material, acellular hybrid scaffolds consisting of in situ cross-linkable 3-D interpenetrating network structures were obtained by decellularization of the meniscus tissues followed by integration of the gel system. Decellularization efficiency was confirmed using a DNA quantification assay (82% decrease in DNA content) and histological stainings. In the second part of the study, the gelatin molecule was functionalized by adding methacrylic anhydride and the degree of functionalization was found to be 75% by (Proton-Nuclear Magnetic Resonance) ¹H-NMR. Using this, a series of hybrid constructs named GelMA-Hybrid (G-Hybrid), GELMA/PEGDMA-Hybrid (PG-Hybrid), and GelMA/PEGDMA/HAMA-Hybrid (PGH-Hybrid) were prepared by cross-linking with UVA. Changes in the chemical structure were determined with Fourier Transform Infrared Spectrophotometer (FTIR). Water uptake capacities of cross-linked hybrid structures were measured in swelling studies, and it was found that hybrid scaffolds showed similar swelling properties compared to native counterparts. By compressive mechanical tests, enhanced mechanical properties were revealed in cross-linked scaffolds with PGH-Hybrid having the highest cross-link density. Protein denaturation and decomposition transition temperatures were improved by adding hydrogels to acellular scaffolds according to thermal gravimetric analyses (TGA). Cross-linked acellular scaffolds have exhibited a behavior close to native tissues with below 25% mass loss in phosphate buffer saline (PBS) and enzymatic solution. Cell viability was examined through Alamar Blue on the first day and cell viability in hybrid constructs was found to be above 80% while it was closer to the control group on the 7^th day. It was concluded that the developed biomaterials could be used in meniscus tissue engineering with their tunable physicochemical and mechanical properties.

A longer duration from injury to surgery is associated with preoperative deterioration of an isolated meniscal tear in patients aged 40 years or older

PURPOSE

To evaluate the preoperative deterioration of an isolated meniscal tear in patients aged 40 years or older, and whether time from injury to surgery is associated with worsening of a meniscal tear.

METHODS

Patients aged 40 years or older who underwent arthroscopic surgery for isolated meniscal tear between 2014 and 2019 were retrospectively reviewed. The diagnostic magnetic resonance imaging (MRI) findings and arthroscopic findings were compared to evaluate the deterioration of meniscal tears. Predictors of the development of meniscal tears; patient demographic factors, duration from injury to surgery (injury to MRI and MRI to surgery), and image findings were assessed.

RESULTS

A total of 58 patients (58 knees) were included (mean age, 55.9 ± 8.5 years; male/female, 31/27). An isolated meniscal tear deteriorated in 28 (48.3%). Compared patients with and without deteriorated meniscal tear, significant differences were found in the MRI grade of meniscal tear (p = 0.03), duration from injury to MRI (164.2 ± 167.9 vs 45.2 ± 48.7 days, p < 0.001), and from MRI to surgery (148.8 ± 91.1 vs 67.6 ± 56.7 days, p < 0.001). A multivariate regression analysis showed that the duration from injury to MRI (odds ratio [OR], 1.03; p < 0.001) and from MRI to surgery (OR, 1.02; p < 0.001) were independent predictors.

CONCLUSION

Approximately 50% of isolated meniscal tears deteriorated preoperatively in patients aged 40 years or older. The duration from injury to surgery was an independent predictor of worsening of an isolated meniscal tear.

Effects of and Response to Mechanical Loading on the Knee

Mechanical loading to the knee joint results in a differential response based on the local capacity of the tissues (ligament, tendon, meniscus, cartilage, and bone) and how those tissues subsequently adapt to that load at the molecular and cellular level. Participation in cutting, pivoting, and jumping sports predisposes the knee to the risk of injury. In this narrative review, we describe different mechanisms of loading that can result in excessive loads to the knee, leading to ligamentous, musculotendinous, meniscal, and chondral injuries or maladaptations. Following injury (or surgery) to structures around the knee, the primary goal of rehabilitation is to maximize the patient's response to exercise at the current level of function, while minimizing the risk of re-injury to the healing tissue. Clinicians should have a clear understanding of the specific injured tissue(s), and rehabilitation should be driven by knowledge of tissue-healing constraints, knee complex and lower extremity biomechanics, neuromuscular physiology, task-specific activities involving weight-bearing and non-weight-bearing conditions, and training principles. We provide a practical application for prescribing loading progressions of exercises, functional activities, and mobility tasks based on their mechanical load profile to knee-specific structures during the rehabilitation process. Various loading interventions can be used by clinicians to produce physical stress to address body function, physical impairments, activity limitations, and participation restrictions. By modifying the mechanical load elements, clinicians can alter the tissue adaptations, facilitate motor learning, and resolve corresponding physical impairments. Providing different loads that create variable tensile, compressive, and shear deformation on the tissue through mechanotransduction and specificity can promote the appropriate stress adaptations to increase tissue capacity and injury tolerance. Tools for monitoring rehabilitation training loads to the knee are proposed to assess the reactivity of the knee joint to mechanical loading to monitor excessive mechanical loads and facilitate optimal rehabilitation.

Three-dimensional and 3-Tesla MRI morphometry of knee meniscus in normal and pathologic state

INTRODUCTION

To conduct a morphometric analysis of intact and torn menisci using isotropic meniscus plane three-dimensional (3D) reconstructions on 3-Tesla MRI and compare 2D versus 3D MRI for meniscus tear characterization.

MATERIALS AND METHODS

One hundred thirty three normal menisci from 92 patients (39 male, 53 female), and 38 arthroscopy-proven torn menisci from 36 patients (23 male, 13 female) were evaluated using 3D isotropic multi-planar MRI reconstructions and 2D MRI. Two observers measured the tibial plateau height and area, meniscal height, axial plane cross-sectional areas, and extrusion of intact menisci. Two observers also measured the meniscal tear length, tear area, and residual area of pathological menisci on 2D and 3D MRI. Intraclass correlation coefficients (ICC) were obtained. Institutional Review Board approval was obtained, and the informed consent was waived.

RESULTS

Medial meniscus (MM) and lateral meniscus (LM) areas were 503.6 ± 85.1 mm² and 396.6 ± 72.0 mm² for Observer 1, and 515.8 ± 82.1 mm² and 408.0 ± 68.3 mm² for Observer 2 (ICC:0.86, 0.87). In torn menisci, average tear length, area, and residual area were 36.3 ± 13.6 mm, 182.6 ± 139.3 mm² , and 235.4 ± 140.3 mm² , respectively for Observer 1, and 38.9 ± 14.7 mm, 181.2 ± 135.6 mm² , 238.2 ± 140.5 mm² for Observer 2. In the MM and LM, bucket-handle and complex tears were largest in areas, respectively. ICCs were excellent (0.91-1.0) on 3D MRI and moderate-good (0.57-0.81) on 2D MRI.

CONCLUSION

Meniscus morphometry on 3D MRI shows moderate to excellent inter-observer reliability and meniscus tear extent is more reliably defined on 3D MRI than 2D MRI. Residual meniscus-area calculation can be performed on 3D MRI.

Predicting meniscal tear stability across knee-joint flexion using finite-element analysis

PURPOSE

To analyse the stress distribution through longitudinal and radial meniscal tears in three tear locations in weight-bearing conditions and use it to ascertain the impact of tear location and type on the potential for healing of meniscal tears.

METHODS

Subject-specific finite-element models of a healthy knee under static loading at 0°, 20°, and 30° knee flexion were developed from unloaded magnetic resonance images and weight-bearing, contrast-enhanced computed tomography images. Simulations were then run after introducing tears into the anterior, posterior, and midsections of the menisci.

RESULTS

Absolute differences between the displacements of anterior and posterior segments modelled in the intact state and those quantified from in vivo weight-bearing images were less than 0.5 mm. There were tear-location-dependent differences between hoop stress distributions along the inner and outer surfaces of longitudinal tears; the longitudinal tear surfaces were compressed together to the greatest degree in the lateral meniscus and were most consistently in compression on the midsections of both menisci. Radial tears resulted in an increase in stress at the tear apex and in a consistent small compression of the tear surfaces throughout the flexion range when in the posterior segment of the lateral meniscus.

CONCLUSIONS

Both the type of meniscal tear and its location within the meniscus influenced the stresses on the tear surfaces under weight bearing. Results agree with clinical observations and suggest reasons for the inverse correlation between longitudinal tear length and healing, the inferior healing ability of medial compared with lateral menisci, and the superior healing ability of radial tears in the posterior segment of the lateral meniscus compared with other radial tears. This study has shown that meniscal tear location in addition to type likely plays a crucial role in dictating the success of non-operative treatment of the menisci. This may be used in decision making regarding conservative or surgical management.

Conservative Management of Possible Meniscal Derangement Using the Mulligan Concept: A Case Report

Objective

The purpose of this case study was to report on the immediate effects of the combined use of mobilizations with movement and the "squeeze" technique on a patient with knee stiffness, popping, and swelling.

Clinical Features

The patient presented with right knee stiffness, swelling, and a popping sensation of insidious onset. Clinical examination revealed pain with terminal knee extension and flexion, joint line tenderness, a positive Apley's compression test, and a positive Thessaly's test at 20° of knee flexion. A working diagnosis was established of a meniscal pathology with the differential diagnoses of meniscal derangement and synovial plica.

Intervention and Outcome

The patient received 3 total treatments using the Mulligan concept over the course of 11 days. The treatments included the application of a tibia internal rotation mobilization with movement and the "squeeze" technique to the affected knee. Patient outcomes, including the Disablement in the Physically Active Scale, the Patient-Specific Functional Scale, and the Numeric Rating Scale for pain, were collected throughout the course of treatment. The patient reported a minimal clinically important difference on the Numeric Rating Scale for pain after each treatment and on all outcomes after the third treatment. The patient reported improvement on her follow-up visit 4 days after the third treatment; the results of a clinical exam and patient outcomes supported a complete discharge after 3 treatments.

Conclusion

This patient responded favorably to use of the Mulligan concept as a manual therapy technique for the treatment of symptoms related to possible meniscal derangement.

The effect of hip joint muscle exercise on muscle strength and balance in the knee joint after meniscal injury

[Purpose] This study aimed to evaluate the effect of hip muscle strengthening on muscle strength and balance in the knee joint after a meniscal injury. [Subjects and Methods] This randomized control study enrolled 24 patients who had undergone arthroscopic treatment after a meniscal injury and began a rehabilitative exercise program 8 weeks after surgery. Subjects were divided into 2 groups of 12 subjects each: gluteus medius resistance exercise group and control group. This study investigated muscle strength and balance in the knee joint flexor, extensor, and abductor during an 8-week period. [Results] Measurements of knee extensor muscle strength revealed no significant difference between the control group and the experimental group. Measurements of abductor muscle strength, however, identified a significant difference between the 2 groups. The groups did not differ significantly with regard to balance measurements. [Conclusion] The results of this study suggest that this subject should be approached in light of the correlation between the hip abductor and injury to the lower extremities.

Tissue adhesives for meniscus tear repair: an overview of current advances and prospects for future clinical solutions

Menisci are crucial structures in the knee joint as they play important functions in load transfer, maintaining joint stability and in homeostasis of articular cartilage. Unfortunately, ones of the most frequently occurring knee injuries are meniscal tears. Particularly tears in the avascular zone of the meniscus usually do not heal spontaneously and lead to pain, swelling and locking of the knee joint. Eventually, after a (partial) meniscectomy, they will lead to osteoarthritis. Current treatment modalities to repair tears and by that restore the integrity of the native meniscus still carry their drawbacks and a new robust solution is desired. A strong tissue adhesive could provide such a solution and could potentially improve on sutures, which are the current gold standard. Moreover, a glue could serve as a carrier for biological compounds known to enhance tissue healing. Only few tissue adhesives, e.g., Dermabond(®) and fibrin glue, are already successfully used in clinical practice for other applications, but are not considered suitable for gluing meniscus tissue due to their sub-optimal mechanical properties or toxicity. There is a growing interest and research field focusing on the development of novel polymer-based tissue adhesives, but up to now, there is no material specially designed for the repair of meniscal tears. In this review, we discuss the current clinical gold standard treatment of meniscal tears and present an overview of new developments in this field. Moreover, we discuss the properties of different tissue adhesives for their potential use in meniscal tear repair. Finally, we formulate recommendations regarding the design criteria of material properties and adhesive strength for clinically applicable glues for meniscal tears.

Optical spectroscopic determination of human meniscus composition

This study investigates the correlation between the composition of human meniscus and its absorption spectrum in the visible (VIS) and near infrared (NIR) spectral range. Meniscus samples (n = 24) were obtained from nonarthritic knees of human cadavers with no history of joint diseases. Specimens (n = 72) were obtained from three distinct sections of the meniscus, namely; anterior, center, posterior. Absorption spectra were acquired from each specimen in the VIS and NIR spectral range (400-1,100 nm). Following spectroscopic probing, the specimens were subjected to biochemical analyses to determine the matrix composition, that is water, hydroxyproline, and uronic acid contents. Multivariate analytical techniques, including principal component analysis (PCA) and partial least squares (PLS) regression, were then used to investigate the correlation between the matrix composition and it spectral response. Our results indicate that the optical absorption of meniscus matrix is related to its composition, and this relationship is optimal in the NIR spectral range (750-1,100 nm). High correlations (R(2) (uronic)  = 86.9%, R(2) (water)  = 83.8%, R(2) (hydroxyproline)  = 81.7%, p < 0.0001) were obtained between the spectral predicted and measured meniscus composition, thus suggesting that spectral data in the NIR range can be utilized for estimating the matrix composition of human meniscus. In conclusion, optical spectroscopy, particularly in the NIR spectral range, is a potential method for evaluating the composition of human meniscus. This presents a promising technique for rapid and nondestructive evaluation of meniscus integrity in real-time during arthroscopic surgery.

Treatment of meniscal tears: An evidence based approach

Treatment options for meniscal tears fall into three broad categories; non-operative, meniscectomy or meniscal repair. Selecting the most appropriate treatment for a given patient involves both patient factors (e.g., age, co-morbidities and compliance) and tear characteristics (e.g., location of tear/age/reducibility of tear). There is evidence suggesting that degenerative tears in older patients without mechanical symptoms can be effectively treated non-operatively with a structured physical therapy programme as a first line. Even if these patients later require meniscectomy they will still achieve similar functional outcomes than if they had initially been treated surgically. Partial meniscectomy is suitable for symptomatic tears not amenable to repair, and can still preserve meniscal function especially when the peripheral meniscal rim is intact. Meniscal repair shows 80% success at 2 years and is more suitable in younger patients with reducible tears that are peripheral (e.g., nearer the capsular attachment) and horizontal or longitudinal in nature. However, careful patient selection and repair technique is required with good compliance to post-operative rehabilitation, which often consists of bracing and non-weight bearing for 4-6 wk.

A multilayer tissue engineered meniscus substitute

Various methods have been tried to treat the main meniscus problem, meniscal tears, for which we believe tissue engineering could be a viable solution. In this study, a three dimensional, collagen-based meniscus substitute was prepared by tissue engineering using human fibrochondrocytes and a collagen based-scaffold. This construct was made with 3 different collagen-based foams interspaced with two electrospun nano/microfibrous mats. The top layer was made of collagen type I-chondroitin sulfate-hyaluronic acid (Coll-CS-HA), and the middle and the bottom layers were made of only collagen type I with different porosities and thus with different mechanical properties. The mats of aligned fibers were a blend of collagen type I and poly(L-lactic acid-co-glycolic acid) (PLGA). After seeding with human fibrochondrocytes, cell attachment, proliferation, and production of extracellular matrix and glucoseaminoglycan were studied. Cell seeding had a positive effect on the compressive properties of foams and the 3D construct. The 3D construct with all its 5 layers had better mechanical properties than the individual foams.

The location of knee pain and pathology in patients with a presumed meniscus tear: preoperative symptoms compared to arthroscopic findings

BACKGROUND

Pain is one of the primary motivations for patients to seek medical advice. Pain location is one element in the process of formulating a diagnosis.

AIMS

The purpose of the study is to determine if there is a correlation between the location of pain and the location of pathology in the knees of patients with a suspected meniscus tear.

METHODS

From a possible 856 patients referred for arthroscopy, 213 patients consented to be included in the study and 193 (90 %) completed the study. The participating subjects located area of their symptoms on a diagram showing the four aspects of the knee joint. For analysis purposes symptoms were grouped into medial, lateral, posterior, or a combination of these areas. Pathology identified at arthroscopy was recorded on the International Knee Documentation Committee (IKDC) surgical form. The location of knee pathology was divided into medial compartment, lateral compartment or combinations of pathologies. Locations of pain were analysed for an association with the location of pathology found at arthroscopy.

RESULTS

Of the 193 subjects who completed the study, 69 (35.7 %) of the subjects presented with one location of pain i.e. medial, lateral or posterior pain and the remaining 124 (64.3 %) had multiple areas. In correlating locations of reported pain with pathology, there was no significant correlation found (p = 0.98).

CONCLUSIONS

This study found no direct correlation between the location of pain and the location of pathology in the knee in patients with a suspected meniscus tear.

Repair of radial tears and posterior horn detachments of the lateral meniscus: minimum 2-year follow-up

PURPOSE

The aim of this study was to show that repair of posterior radial tears and horn detachments of the lateral meniscus is possible and to assess the outcomes.

METHODS

A retrospective review of 24 patients who had repair of a posterior defunctioning tear of the lateral meniscus combined with anterior cruciate ligament reconstruction was undertaken. Patients completed a follow-up postal questionnaire that included Lysholm, subjective International Knee Documentation Committee (IKDC), and Tegner scoring systems.

RESULTS

Eight patients had suture repair of a lateral meniscal radial tear. The mean Lysholm, IKDC, and Tegner scores were 86.9 (SD, 11.6), 81.6 (SD, 13.9), and 5.8 (SD, 2.7), respectively, at a mean follow-up of 70.5 months (range, 29.0 to 168.0 months). Subsequent arthroscopy in 2 patients confirmed meniscal healing. Sixteen patients underwent a posterior horn reattachment. The mean Lysholm, subjective IKDC, and Tegner scores were 86.1 (SD, 13.3), 84.3 (SD, 17.0), and 6.5 (SD, 2.1), respectively, at a mean follow-up of 53.6 months (range, 26.0 to 116.0 months). Three patients had subsequent magnetic resonance imaging and/or arthroscopy that indicated meniscal healing. Two further patients had reinjury, and magnetic resonance imaging and/or arthroscopy showed that their repairs had failed.

CONCLUSIONS

Posterior radial tears that extend to the capsule and posterior horn detachments of the lateral meniscus are frequently amenable to repair. In this study 22 of 24 repairs functioned successfully over a mean follow-up of 58.6 months (range, 26.0 to 168.0 months).

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Biomechanics of the meniscus-meniscal ligament construct of the knee

The menisci of the knee act primarily to redistribute contact force across the tibio-femoral articulation. This meniscal function is achieved through a combination of the material, geometry and attachments of the menisci. The main ligaments that attach the menisci to the tibia (insertional ligaments, deep medial collateral ligament), the femur (meniscofemoral ligaments, deep medial collateral ligament) and each other (the anterior intermeniscal ligament) are the means by which the contact force between tibia and femur is distributed into hoop stresses in the menisci to reduce contact pressure at the joint. This means that the functional biomechanics of the menisci cannot be considered in isolation and should be considered as the functional biomechanics of the meniscus-meniscal ligament construct. This article presents the current knowledge on the anatomy and functional biomechanics of the meniscus and its associated ligaments. Much is known about the function of the meniscus-meniscal ligament construct; however, there still remain significant gaps in the literature in terms of the properties of the anterior intermeniscal ligament and its function, the properties of the insertional ligaments, and the most appropriate ways to reconstruct meniscal function surgically.