Natural history and clinical significance of meniscal tears over 8 years in a midlife cohort

Bitesize Epidemiology for General Awareness of All Students - I

This is the first part of a two-part series article. Recently, we have been in the middle of a difficult time due to the Covid-19 pandemic. Pandemics or global epidemics are not new to humankind; they have occurred many times in history. The discourse of epidemiology describes mainly the causal factors which need to be mitigated to prevent or combat the effects of epidemics. In epidemiology, we are not concerned for a person, but rather every individual globally, to make life healthier for all. In this article, we will discuss the basics of epidemiological practice that scientists have used for centuries to prevent epidemics with great results. Overall, we plan for better global health aided by epidemiology.

The relationship between meniscal pathologies, cartilage loss, joint replacement and pain in knee osteoarthritis: a systematic review

OBJECTIVE

We conducted a systematic review in order to understand the relationship between imaging-visualised meniscus pathologies, hyaline cartilage, joint replacement and pain in knee osteoarthritis (OA).

DESIGN

A search of the Medline, Excerpta Medica database (EMBASE) and Cochrane library databases was performed for original publications reporting association between imaging-detected meniscal pathology (extrusion or tear/damage) and longitudinal and cross-sectional assessments of hyaline articular cartilage loss [assessed on magnetic resonance imaging (MRI)], incident joint replacement and pain (longitudinal and cross-sectional) in knee OA. Each association was qualitatively characterised by a synthesis of data from each analysis, based upon study design and quality scoring (including risk of bias assessment and adequacy of covariate adjustment using Cochrane recommended methodology).

RESULTS

In total 4,878 abstracts were screened and 82 publications were included (comprising 72 longitudinal analyses and 49 cross-sectional). Using high quality, well-adjusted data, meniscal extrusion and meniscal tear/damage were associated with longitudinal progression of cartilage loss, cross-sectional cartilage loss severity and joint replacement, independently of age, sex and body mass index (BMI). Medial and lateral meniscal tears were associated with cartilage loss when they occurred in the body and posterior horns, but not the anterior horns. There was a lack of high quality, well-adjusted meniscal pathology and pain publications and no clear independent association between meniscal extrusion or tear/damage with pain severity, progression in pain or incident frequent knee symptoms.

CONCLUSION

Meniscal features have strong associations with cartilage loss and joint replacement in knee OA, but weak associations with knee pain. Systematic review PROSPERO registration number: CRD 42020210910.

Current Controversies in Arthroscopic Partial Meniscectomy

PURPOSE OF REVIEW

Given the continued controversy among orthopedic surgeons regarding the indications and benefits of arthroscopic partial meniscectomy (APM), this review summarizes the current literature, indications, and outcomes of partial meniscectomy to treat symptomatic meniscal tears.

RECENT FINDINGS

In patients with symptomatic meniscal tears, the location and tear pattern play a vital role in clinical management. Tears in the central white-white zone are less amenable to repair due to poor vascularity. Patients may be indicated for APM or non-surgical intervention depending on the tear pattern and symptoms. Non-surgical management for meniscal pathology includes non-steroidal anti-inflammatory drugs (NSAIDs), physical therapy (PT), and intraarticular injections to reduce inflammation and relieve symptoms. There have been several landmark multicenter randomized controlled trials (RCTs) studying the outcomes of APM compared to PT or sham surgery in symptomatic degenerative meniscal tears. These most notably include the 2013 Meniscal Tear in Osteoarthritis Research (MeTeOR) Trial, the 2018 ESCAPE trial, and the sham surgery-controlled Finnish Degenerative Meniscal Lesion Study (FIDELITY), which failed to identify substantial benefits of APM over nonoperative treatment or even placebo surgery. Despite an abundance of literature exploring outcomes of APM for degenerative meniscus tears, there is little consensus among surgeons about the drivers of good outcomes following APM. It is often difficult to determine if the presenting symptoms are secondary to the meniscus pathology or the degenerative disease in patients with concomitant OA. A central tenet of managing meniscal pathology is to preserve tissue whenever possible. Most RCTs show that exercise therapy may be non-inferior to APM in degenerative tears if repair is not possible. Given this evidence, patients who fail nonoperative treatment should be counseled regarding the risks of APM before proceeding to surgical management.

MRI findings of acute anterior instability of the knee in the absence of recent trauma

BACKGROUND

Anterior knee instability is usually encountered in the context of trauma, with the clinical examination and imaging focusing on anterior cruciate ligament (ACL) disruption. Limited data exist on magnetic resonance imaging (MRI) of acute anterior knee instability in the absence of recent trauma.

PURPOSE

To provide the first comprehensive account of MRI findings in acute anterior knee laxity in the absence of acute trauma and to evaluate predictors of ACL integrity and pain.

MATERIAL AND METHODS

A total of 84 consecutive patients with non-traumatic knee instability were prospectively studied. Instability was assessed with Lachman's, pivot shift, and Lelli's tests. MRI findings were recorded, and ACL integrity was surgically confirmed in all 24 cases of MRI suggesting tear and in 21/60 cases of MRI suggesting no tear. Binary logistic regression models were used to identify predictors of ACL tears and pain, and Mann-Whitney U test served for comparisons between continuous variables. The study was approved by the institutional review board.

RESULTS

Osteoarthritis and notch bony outgrowth (NBO) were present in 44% and 42.9% of all knees, respectively. NBO did not correlate with osteoarthritis (P = 0.606). NBO (odds ratio [OR] = 4.157; P = 0.016) and ACL grafts (OR = 9.277; P = 0.01) predisposed to non-traumatic ACL tears (torn in 28.6% of total cases). Presence of osteoarthritis was predictive of pain (OR = 17.671; P < 0.001).

CONCLUSION

We present a comprehensive analysis of MRI findings in clinically significant non-traumatic anterior instability, showing that NBO and ACL grafts predispose in non-traumatic ACL tears, whereas osteoarthritis is the only predictor of pain.

Meniscus tears accelerate joint space loss and lateral meniscal extrusion increases risk of knee arthroplasty in middle-aged adults

We sought to use publicly available data from the Osteoarthritis Initiative (OAI), a multicenter prospective cohort study, to determine the rate of joint space loss and likelihood of knee arthroplasty due to magnetic resonance imaging (MRI)-diagnosed meniscal tears or meniscal extrusion in middle-aged adults with no to mild knee osteoarthritis. Participants (n = 2199; mean age, 60.2 years) with Kellgren-Lawrence osteoarthritis grades 2 (mild) (48.7%) or 0 to 1 (none) (51.3%) underwent knee MRIs at enrollment and were followed radiographically for 8 years and for total knee arthroplasty (TKA) for 9 years. Rate of joint space loss and risk of arthroplasty due to meniscal tears and/or extrusion were determined by multivariate modeling. Prevalence of baseline medial meniscus tears was 21.3% and lateral tears was 12.8%; 26.9% had medial meniscal extrusion (79.6%, <2 mm; 20.4%, +2 mm) and 5.4% had lateral extrusion (75.9%, <2 mm; 24.1%, +2 mm). Median medial joint space loss was 0.06 mm/y and lateral was 0.05 mm/y. Medial tears regardless of extrusion were associated with accelerated medial joint space loss (additional mean, 0.05 mm/y; P = .001). Lateral tears were associated with accelerated lateral joint space loss (additional 0.09 mm/y; P < .001) as was lateral extrusion (additional 0.10 mm/y; P < .001). The yearly incidence of knee arthroplasty was 0.5% without lateral extrusion, 1.5% with extrusion less than 2.0 mm, and 3.7% with extrusion greater than or equal to 2.0 mm. Both medial and lateral tears accelerate joint space loss in middle-aged adults. Lateral meniscal extrusion further accelerates joint space loss and increases risk of progression to TKA within 9 years.

Application of Disease Etiology and Natural History to Prevention in Primary Health Care: A Discourse

The principles of etiology and natural history of disease are essential to recognizing opportunities for prevention across the illness spectrum. They have a bearing on how illness is experienced, how differently it can be perceived at the time of first contact with the health system, and how it may appear at later stages. Opportunities for prevention arise at every stage in the process, and three main levels are described: primary, secondary, and tertiary. Prevention strategies include health promotion focused on determinants, clinical prevention to reduce modifiable risk factors, case finding, screening, and addressing functional outcomes relevant to quality of life; the importance of preventing errors is also recognized. The distinction between incidence effects and treatment effects of prevention is explored. This review also examines the differing roles of language in health science and public communication, aspects of disease classification, related issues in patient-centered care, the prevention paradox, and integrated models of disease prevention.

The effect of weight loss on the progression of meniscal extrusion and size in knee osteoarthritis: a post-hoc analysis of the Intensive Diet and Exercise for Arthritis (IDEA) trial

OBJECTIVE

Weight loss has beneficial effects on clinical outcomes in knee osteoarthritis (OA), but the mechanism is still unclear. Since meniscus extrusion is associated with knee pain, this study assessed whether weight loss by diet and/or exercise is associated with less progression in meniscus extrusion measures over time.

DESIGN

The Intensive Diet and Exercise for Arthritis trial (IDEA) was a prospective, single-blind, randomized-controlled trial including overweight and obese older adults with knee pain and radiographic OA. Participants were randomized to 18-month interventions: exercise only, diet only or diet + exercise. In a random subsample of 105 participants, MRIs were obtained at baseline and follow-up. The medial and lateral menisci were segmented and quantitative position and size measures were obtained, along with semiquantitative extrusion measures. Linear and log-binomial regression were used to examine the association between change in weight and change in meniscus measures. Between-group differences were analyzed using an analysis of covariance.

RESULTS

Weight loss was associated with less progression over time of medial meniscus extrusion as measured by the maximum (β: -24.59 μm, 95%CI: -41.86, -7.33) and mean (β: -19.08 μm, 95%CI: -36.47, -1.70) extrusion distances. No relationships with weight loss were observed for lateral meniscus position, medial or lateral meniscus size or semiquantitative measures. Change in meniscus position and size did not differ significantly between groups.

CONCLUSIONS

Weight loss was associated with beneficial modifications of medial meniscus extrusion over 18 months. This may be one of the mechanisms by which weight loss translates into a clinical benefit.

CLINICAL TRIAL REGISTRATION

NCT00381290.

Characterization and Comparison of Postnatal Rat Meniscus Stem Cells at Different Developmental Stages

Meniscus‐derived stem cells (MeSCs) are a potential cell source for meniscus tissue engineering. The stark morphological and structural changes of meniscus tissue during development indicate the complexity of MeSCs at different tissue regions and stages of development. In this study, we characterized and compared postnatal rat meniscus tissue and MeSCs at different tissue regions and stages of development. We observed that the rat meniscus tissue exhibited marked changes in tissue morphology during development, with day 7 being the most representative time point of different developmental stages. All rat MeSCs displayed typical stem cell characteristics. Rat MeSCs derived from day 7 inner meniscus tissue exhibited the highest self‐renewal capacity, cell proliferation, differentiation potential toward various mesenchymal lineage and the highest expression levels of chondrogenic genes and proteins. Transplantation of rat MeSCs derived from day 7 inner meniscus tissue promoted neo‐tissue formation and effectively protected joint surface cartilage in vivo. Our results demonstrated for the first time that rat MeSCs are not necessarily better at earlier developmental stages, and that rat MeSCs derived from day 7 inner meniscus tissue may be a superior cell source for effective meniscus regeneration and articular cartilage protection. This information could make a significant contribution to human meniscus tissue engineering in the future. stem cells translational medicine2019;8:1318&1329

(A): Meniscus tissue at different tissue regions and stages of development. (B): MeSCs at different tissue regions and stages of development. (C): Intra‐articular injection of MeSCs for meniscus regeneration and OA suppression. *Significant difference between two groups at p < .05. **Significant difference between two groups at p < .01. ***Significant difference between two groups at p < .001. ****Significant difference between two groups at p < .0001. N.S., No significant difference between two groups at p ≥ .05.

Effect of degenerative and radial tears of the meniscus and resultant meniscectomy on the knee joint: a finite element analysis

Objective

The objective of this study is to investigate the biomechanics on the knee components caused by degenerative and radial meniscal tears and resultant meniscectomy.

Methods

A detailed finite element model of the knee joint with bones, cartilages, menisci and main ligaments was constructed from a combination of computed tomography and magnetic resonance images. Degenerative and radial tears of both menisci and resultant medial meniscectomy were used and two different kinds of simulations, the vertical and the anterior load, mimicking the static stance and slight flexion simulations, were applied on the model. The compressive and shear stress and meniscus extrusion were evaluated and compared.

Results

Generally, both degenerative and radial tears lead to increased peak compressive and shear stress of both cartilages and menisci and large meniscus extrusion, and the medial meniscal tear induced larger value of stress and extrusion than the lateral meniscal tear. The peak stress and meniscus extrusion further elevated after the medial meniscus meniscectomy. Distribution of stress was shifted from the intact hemi joint to the injured hemi joint with either medial or lateral meniscal tear.

Conclusion

Our finite element model provides a realistic three-dimensional knee model to investigate the effects of degenerative and radial meniscal tears and resultant meniscectomy on the stress distribution of the knee. The stress was increased in meniscal tears and increased significantly when meniscectomy was performed. Increased meniscus extrusion may explain the mechanism for higher stress on the components of the knee.

The translational potential of this article

Meniscal tears are the most common damage associated to the menisci, and meniscectomy is often performed to relieve the pain and instability of the knee. The results of our study indicated increased stress on cartilages and menisci, which may lead to early onset of osteoarthritis. This may guide surgeons to preserve more of the meniscus when performing meniscectomy.

Arthroscopic meniscal surgery versus conservative management in patients aged 40 years and older: a meta-analysis

INTRODUCTION

The efficacy of arthroscopic meniscus surgery in old aged patients remains controversial. The purpose of the present study was to review published studies comparing arthroscopic meniscal surgery with conservative management to treat meniscal injuries in patients 40 years of age and older.

MATERIALS AND METHODS

Several electronic databases were queried for articles published until July 2017 that evaluated outcomes of arthroscopic meniscal surgery in patients aged 40 years and older. Data searches, extraction, analysis, and quality assessment were performed according to the Cochrane Collaboration guidelines, and the clinical outcomes were evaluated using various outcome values. The results are presented as the standard mean difference (SMD) for continuous outcomes with 95% confidence intervals (CIs).

RESULTS

Nine randomized controlled trials (RCTs) were included. There were no significant differences in clinical outcomes such as relief in knee pain (SMD = 0.01, 95% CIs = - 0.15 to 0.18, I² = 38%) and improved knee function (SMD = 0.01, 95% CIs = - 0.19 to 0.21, I² = 57%) between arthroscopic meniscal surgery and conservative management for degenerative meniscal tears.

CONCLUSIONS

The efficacy of arthroscopic surgery was not superior to conservative management in this type of patients. Therefore, arthroscopic meniscal surgery should not be recommended as a first choice of treatment for degenerative meniscal tears. In patients over 40 years of age, arthroscopic surgery should be cautiously considered for degenerative meniscal tears and only when there has not been a satisfactory response to conservative management.

Short cracks in knee meniscus tissue cause strain concentrations, but do not reduce ultimate stress, in single-cycle uniaxial tension

Tears are central to knee meniscus pathology and, from a mechanical perspective, are crack-like defects (cracks). In many materials, cracks create stress concentrations that cause progressive local rupture and reduce effective strength. It is currently unknown if cracks in meniscus have these consequences; if they do, this would have repercussions for management of meniscus pathology. The objective of this study was to determine if a short crack in meniscus tissue, which mimics a preclinical meniscus tear, (a) causes crack growth and reduces effective strength, (b) creates a near-tip strain concentration and (c) creates unloaded regions on either side of the crack. Specimens with and without cracks were tested in uniaxial tension and compared in terms of macroscopic stress-strain curves and digital image correlation strain fields. The strain fields were used as an indicator of stress concentrations and unloaded regions. Effective strength was found to be insensitive to the presence of a crack (potential effect < 0.86 s.d.; β = 0.2), but significant strain concentrations, which have the potential to lead to long-term accumulation of tissue or cell damage, were observed near the crack tip.

Medial meniscal extrusion: Detection, evaluation and clinical implications

The menisci play an important role in knee kinematics. Their unique anatomy allows them to channel forces generated during knee movements through the larger tibio-femoral condylar surfaces while simultaneously resisting deleterious hoop stresses. Although physiologic meniscal extrusion occurs with every knee joint movement, pathologic meniscal extrusion subjects the knee to persistent and excessive load transmission. This renders the knee structures susceptible to injury or exacerbates worsening of existing knee joint internal derangement. Detection and quantification of meniscus extrusion is important given its association with underlying pathological processes and internal derangements such as cartilage loss, osteoarthritis and meniscal tears. The medial and lateral menisci vary in size, attachments and load transmission, and the medial meniscus is more susceptible to injury. In this article, the authors illustrate the role of meniscus kinematics, and the identification and quantification of medial meniscal extrusion. Multimodality imaging appearances and implications of presence of medial meniscal extrusion in different knee joint pathologies are discussed with review of the relevant literature.

Diagnostic Validity of Combining History Elements and Physical Examination Tests for Traumatic and Degenerative Symptomatic Meniscal Tears

BACKGROUND

The current approach to the clinical diagnosis of traumatic and degenerative symptomatic meniscal tears (SMTs) proposes combining history elements and physical examination tests without systematic prescription of imaging investigations, yet the evidence to support this diagnostic approach is scarce.

OBJECTIVE

To assess the validity of diagnostic clusters combining history elements and physical examination tests to diagnose or exclude traumatic and degenerative SMT compared with other knee disorders.

DESIGN

Prospective diagnostic accuracy study.

SETTINGS

Patients were recruited from 2 orthopedic clinics, 2 family medicine clinics, and from a university community.

PATIENTS

A total of 279 consecutive patients who underwent consultation for a new knee complaint.

METHODS

Each patient was assessed independently by 2 evaluators. History elements and standardized physical examination tests performed by a physiotherapist were compared with the reference standard: an expert physicians' composite diagnosis including a clinical examination and confirmatory magnetic resonance imaging. Participating expert physicians were orthopedic surgeons (n = 3) or sport medicine physicians (n = 2). Penalized logistic regression (least absolute shrinkage and selection operator) was used to identify history elements and physical examination tests associated with the diagnosis of SMT and recursive partitioning was used to develop diagnostic clusters.

MAIN OUTCOME MEASURES

Diagnostic accuracy measures were calculated including sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios (LR+/-) with associated 95% confidence intervals (CIs).

RESULTS

Eighty patients had a diagnosis of SMT (28.7%), including 35 traumatic tears and 45 degenerative tears. The combination a history of trauma during a pivot, medial knee pain location, and a positive medial joint line tenderness test was able to diagnose (LR+ = 8.9; 95% CI 6.1-13.1) or exclude (LR- = 0.10; 95% CI 0.03-0.28) a traumatic SMT. Combining a history of progressive onset of pain, medial knee pain location, pain while pivoting, absence of valgus or varus knee misalignment, or full passive knee flexion was able to moderately diagnose (LR+ = 6.4; 95% CI 4.0-10.4) or exclude (LR- = 0.10; 95% CI 0.03-0.31) a degenerative SMT. Internal validation estimates were slightly lower for all clusters but demonstrated positive LR superior to 5 and negative LR inferior to 0.2 indicating moderate shift in posttest probability.

CONCLUSION

Diagnostic clusters combining history elements and physical examination tests can support the differential diagnosis of SMT. These results represent the initial derivation of the clusters and external validation is mandatory.

LEVEL OF EVIDENCE

I.