Meniscus morphology: Does tear type matter? A narrative review with focus on relevance for osteoarthritis research

Meniscal Radial Tears Repaired with All-Inside and Inside-Out Techniques Result in Improved Clinical Outcome Scores; However, More Complications are Reported After Inside-Out Repair: A Systematic Review

PURPOSE

To compare patient-reported outcomes (PROs), failure, and healing rates following all-inside (AI) repair versus inside-out (IO) repair for the treatment of meniscal radial tears.

METHODS

A literature search was performed according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Scopus, PubMed, and Embase computerized databases. Level of evidence I through IV human clinical studies evaluating PROs and/or the incidence of failure and healing following AI versus IO repairs for meniscal radial tears were included. Clinical failure was defined by the presence of joint-line tenderness, a positive McMurray test, and mechanical symptoms such as locking, catching, or giving way. Study quality was assessed using the Methodological Index for Non-Randomized Studies (MINORS) criteria and Modified Coleman Methodology Score (MCMS).

RESULTS

Ten studies published from 2008 to 2023 comprising 205 patients were identified including 142 patients who underwent AI repair and 63 patients who underwent IO repair for radial meniscus tears. Postoperative Lysholm and Tegner scores ranged from 90.8 to 95.6 and 5.7 to 8.2, respectively, in the AI repair group, compared to 86.9 to 94.2 and 6 to 7.5, respectively, in the IO repair group, and all patients exceeded published values for MCID for the Lysholm score. Clinical failure ranged from 0% to 40% in the AI group and 0% to 62.5% in the IO group. Healing assessments on second-look arthroscopy revealed failure rates ranging from 0% to 13.3% in the AI group and 0% to 39% in the IO group. Complete and partial healing ranged from 28.6% to 92.3% in the AI group and from 25% to 70% in the IO group. Chondral damage on second-look arthroscopy ranged from 0% to 95% in the IO group and 0% to 57.7% in the AI group. Postoperative complications ranged from 0%-2% within the AI group, while no complications were reported in the IO group. No implant-related complications were reported in any study group.

CONCLUSION

Both all-inside and inside-out repairs for meniscal radial tears demonstrated improved PROs; however, current literature suggests that the IO technique may have higher failure rates both clinically and on second-look arthroscopy.

Temporal progression of subchondral bone alterations in OA models involving induction of compromised meniscus integrity in mice and rats: A scoping review

OBJECTIVE

To categorize the temporal progression of subchondral bone alterations induced by compromising meniscus integrity in mouse and rat models of knee osteoarthritis (OA).

METHOD

Scoping review of investigations reporting subchondral bone changes with appropriate negative controls in the different mouse and rat models of OA induced by compromising meniscus integrity.

RESULTS

The available literature provides appropriate temporal detail on subchondral changes in these models, covering the entire spectrum of OA with an emphasis on early and mid-term time points. Microstructural changes of the subarticular spongiosa are comprehensively described; those of the subchondral bone plate are not. In mouse models, global subchondral bone alterations are unidirectional, involving an advancing sclerosis of the trabecular structure over time. In rats, biphasic subchondral bone alterations begin with an osteopenic degeneration and loss of subchondral trabeculae, progressing to a late sclerosis of the entire subchondral bone. Rat models, independently from the applied technique, relatively faithfully mirror the early bone loss detected in larger animals, and the late subchondral bone sclerosis observed in human advanced OA.

CONCLUSION

Mice and rats allow us to study the microstructural consequences of compromising meniscus integrity at high temporal detail. Thickening of the subchondral bone plate, an early loss of thinner subarticular trabecular elements, followed by a subsequent sclerosis of the entire subchondral bone are all important and reliable hallmarks that occur in parallel with the advancing articular cartilage degeneration. Thoughtful decisions on the study design, laterality, selection of controls and volumes of interest are crucial to obtain meaningful data.

An All-Suture-Based Technique for Meniscal Repair Is Cost-Effective in Comparison to Partial Meniscectomy for Horizontal Cleavage Tears

Purpose

To determine the cost-effectiveness of meniscal repair (MR) using an all-suture-based technique when compared to partial meniscectomy (PM) for horizontal cleavage tears (HCTs) from a payor's perspective in the United States.

Methods

A state-transition model and cost-utility analysis were developed from a US payor's perspective to project treatment costs and quality-adjusted life-years (QALYs) in a cohort of 35-year-old patients without osteoarthritis at baseline and presenting with either a lateral or medial HCT. Two outpatient costing perspectives were used, namely ambulatory surgical centers (ASCs) and hospitals. The state-transition model had 7 health states with transition probabilities, costs, and utilities obtained from the existing literature. Cost-effectiveness was assessed using a willingness-to-pay threshold of $100,000/QALY, and sensitivity analysis considered the effects of parameter uncertainty on model results. MR failure rates were focused on an all-suture-based technique; however, in a separate scenario, this study considered effectiveness data from various MR techniques and devices.

Results

MR dominated PM over a lifetime horizon, increasing QALYs by 0.43 per patient and decreasing the cost by $12,227 per patient within a hospital setting (and by $12,570 within an ASC). MR with an all-suture-based technique continued to be the dominant treatment when age at primary treatment was varied between 30 and 60 years. Sensitivity analysis showed that MR was not cost-effective in year 1, was cost-effective from year 2, and was cost-saving from year 6 onward from both ASC and hospital perspectives. Probabilistic sensitivity analysis found that MR was cost-effective over a lifetime horizon in 99% of 10,000 iterations on base-case analysis.

Conclusions

Using a lifetime horizon, this study found that from a payor's perspective, MR is a cost-saving intervention when compared with PM in patients with an HCT.

Level of Evidence

Level III, economic analysis.

Meniscal Radial Tears: A Classification System Based on Tear Morphology

Appropriate management of radial meniscal tears is complex, with continued efforts focused on optimizing diagnostic methods for identification to help dictate treatment, especially as surgical indications for repair have expanded, coupled with improvements in surgical techniques and instrumentation. Currently, no standardized classification system for radial meniscal tears exists, limiting the ability to accurately characterize injury patterns and guide surgical decision-making.

The Association between the Extent of the Osteoarthritic Meniscus Degeneration and Cigarette Smoking-A Pilot Study

Background and Objectives: The negative effects of smoking on the musculoskeletal system were presented by many authors, although the relationship between smoking and osteoarthritis remains unclear. The aim of this paper was to investigate the negative effects of smoking on meniscal tissue in osteoarthritic knees by microscopic examination, by adapting the Bonar scoring system and its modifications. Materials and Methods: The study involved 34 patients with varus knees, from whom 65 samples of knee menisci were obtained. The mean age in the studied group was 65.385 years. The smoking status of the patients concluded that there were 13 smokers and 21 nonsmokers. Results: Among smokers, the mean classical Bonar score was 8.42 and the mean modified Bonar score was 6.65, while nonsmokers were characterized by scores of 8.51 and 7.35, respectively. There was a statistically significant negative correlation between the number of cigarettes and the collagen in the medial meniscus (p = 0.0197). Moreover, in the medial meniscus, the modified Bonar score correlated negatively with the number of cigarettes (p = 0.0180). Similarly, such a correlation was observed between the number of cigarettes and the modified Bonar score in the lateral meniscus (p = 0.04571). Furthermore, no correlation was identified between the number of cigarettes and the classical Bonar score in the lateral meniscus. There was a statistically significant difference in the collagen variable value between the smokers and nonsmokers groups (p = 0.04525). Conclusions: The microscopic investigation showed no differences in the menisci of smokers and nonsmokers, except for the collagen, which was more organized in smokers. Moreover, the modified Bonar score was correlated negatively with the number of cigarettes, which supports the role of neovascularization in meniscus pathology under the influence of tobacco smoking.

Predilection of Patellofemoral Cartilage Lesions in Patients with Posterior Medial Meniscal Root Lesions

OBJECTIVE

The present study aims to compare the presence and severity of patellofemoral osteoarthritis between patients with root lesions and non-root lesions.

DESIGN

A total of 102 patients were included in this study (51 root lesions and 51 non-root lesions). The root lesion cohort was matched to a non-root lesion cohort based on sex, body mass index, and age at the time of surgery. Radiographic evaluation with modified Outerbridge scoring of MRI of the knee was performed to determine the severity of degeneration of the knee joint preoperatively. Mann-Whitney and Independent t tests were used to compare the groups.

RESULTS

The root lesion group had statistically greater Outerbridge patella scores (M = 2.45 ± 1.12) and trochlear scores (M = 2.27 ± 1.37) than the non-root lesion patients (M = 1.78 ± 1.30, P = 0.006, and M = 1.55 ± 1.40, P = 0.010, respectively). When using a new scale for grading patellofemoral arthritis, the root lesion group had statistically greater scores (M = 8.33 ± 3.38) than the non-root lesion patients (M = 5.67 ± 3.07) (P < 0.001).

CONCLUSION

Patients with root lesions have a greater degree of patellofemoral cartilage lesions than patients without root lesions. The presence of cartilage lesions preoperatively in root lesion patients has presented the question of whether repair is worthwhile or if one should delay surgery until arthroplasty is indicated. Future research should be carried out on outcomes of root repair surgery in patients with patellofemoral cartilage lesions, in addition to considering the patient's age, activity level, and other risk factors.

Subchondral bone remodeling patterns in larger animal models of meniscal injuries inducing knee osteoarthritis - a systematic review

PURPOSE

Elucidating subchondral bone remodeling in preclinical models of traumatic meniscus injury may address clinically relevant questions about determinants of knee osteoarthritis (OA).

METHODS

Studies on subchondral bone remodeling in larger animal models applying meniscal injuries as standardizing entity were systematically analyzed. Of the identified 5367 papers reporting total or partial meniscectomy, meniscal transection or destabilization, 0.4% (in guinea pigs, rabbits, dogs, minipigs, sheep) remained eligible.

RESULTS

Only early or mid-term time points were available. Larger joint sizes allow reporting higher topographical details. The most frequently reported parameters were BV/TV (61%), BMD (41%), osteophytes (41%) and subchondral bone plate thickness (39%). Subchondral bone plate microstructure is not comprehensively, subarticular spongiosa microstructure is well characterized. The subarticular spongiosa is altered shortly before the subchondral bone plate. These early changes involve degradation of subarticular trabecular elements, reduction of their number, loss of bone volume and reduced mineralization. Soon thereafter, the previously normal subchondral bone plate becomes thicker. Its porosity first increases, then decreases.

CONCLUSION

The specific human topographical pattern of a thinner subchondral bone plate in the region below both menisci is present solely in the larger species (partly in rabbits), but absent in rodents, an important fact to consider when designing animal studies examining subchondral consequences of meniscus damage. Large animal models are capable of providing high topographical detail, suggesting that they may represent suitable study systems reflecting the clinical complexities. For advanced OA, significant gaps of knowledge exist. Future investigations assessing the subchondral bone in a standardized fashion are warranted.

Structural phenotypes of knee osteoarthritis: potential clinical and research relevance

A joint contains many different tissues that can exhibit pathological changes, providing many potential targets for treatment. Researchers are increasingly suggesting that osteoarthritis (OA) comprises several phenotypes or subpopulations. Consequently, a treatment for OA that targets only one pathophysiologic abnormality is unlikely to be similarly efficacious in preventing or delaying the progression of all the different phenotypes of structural OA. Five structural phenotypes have been proposed, namely the inflammatory, meniscus-cartilage, subchondral bone, and atrophic and hypertrophic phenotypes. The inflammatory phenotype is characterized by marked synovitis and/or joint effusion, while the meniscus-cartilage phenotype exhibits severe meniscal and cartilage damage. Large bone marrow lesions characterize the subchondral bone phenotype. The hypertrophic and atrophic OA phenotype are defined based on the presence large osteophytes or absence of any osteophytes, respectively, in the presence of concomitant cartilage damage. Limitations of the concept of structural phenotyping are that they are not mutually exclusive and that more than one phenotype may be present. It must be acknowledged that a wide range of views exist on how best to operationalize the concept of structural OA phenotypes and that the concept of structural phenotypic characterization is still in its infancy. Structural phenotypic stratification, however, may result in more targeted trial populations with successful outcomes and practitioners need to be aware of the heterogeneity of the disease to personalize their treatment recommendations for an individual patient. Radiologists should be able to define a joint at risk for progression based on the predominant phenotype present at different disease stages.

Health-economic evaluation of meniscus tear treatments: a systematic review

PURPOSE

To evaluate the overall evidence of published health-economic evaluation studies on meniscus tear treatment.

METHODS

Our systematic review focuses on health-economic evaluation studies of meniscus tear treatment interventions found in PubMed and Embase databases. A qualitative, descriptive approach was used to analyze the studies' results and systematically report them following PRISMA guidelines. The health-economic evaluation method for each included study was categorized following one of the four approaches: partial economic evaluation (PEE), cost-effectiveness analysis (CEA), cost-benefit analysis (CBA), or cost-utility analysis (CUA). The quality of each included study was assessed using the Consensus on Health Economic Criteria (CHEC) list. Comparisons of input variables and outcomes were made, if applicable.

RESULTS

Sixteen studies were included; of these, six studies performed PEE, seven studies CUA, two studies CEA, and one study combined CBA, CUA, and CEA. The following economic comparisons were analyzed and showed the respective comparative outcomes: (1) meniscus repair was more cost-effective than arthroscopic partial meniscectomy (meniscectomy) for reparable meniscus tear; (2) non-operative treatment or physical therapy was less costly than meniscectomy for degenerative meniscus tear; (3) physical therapy with delayed meniscectomy was more cost-effective than early meniscectomy for meniscus tear with knee osteoarthritis; (4) meniscectomy without physical therapy was less costly than meniscectomy with physical therapy; (5) meniscectomy was more cost-effective than either meniscus allograft transplantation or meniscus scaffold procedure; (6) the conventional arthroscopic instrument cost was lower than laser-assisted arthroscopy in meniscectomy procedures.

CONCLUSION

Results from this review suggest that meniscus repair is the most cost-effective intervention for reparable meniscus tears. Physical therapy followed by delayed meniscectomy is the most cost-effective intervention for degenerative meniscus tears. Meniscus scaffold should be avoided, especially when implemented on a large scale.

LEVEL OF EVIDENCE

Systematic review of level IV studies.

Horizontal Cleavage Meniscus Tears: Biomechanics, Indications, Techniques, and Outcomes

» Accounting for up to 24% of all meniscus tears, horizontal cleavage tears (HCTs) are a common pathology orthopaedic practitioners should be comfortable managing.» Historically, HCTs were treated with partial meniscectomy; however, recent studies have demonstrated that these procedures have an adverse biomechanical effect, while HCT repairs restore the knee's natural biomechanics.» Indications for the surgical repair of HCTs remain disputed, but surgery is generally considered for young, active patients and older patients without significant concomitant osteoarthritis.» Early clinical findings surrounding HCT repair are promising. They suggest that this treatment adequately restores meniscus mechanics, leads to good knee functional outcomes, and results in a high likelihood of return to preinjury activity levels.

Total Knee Arthroplasty After Meniscectomy Is More Likely in Patients With Bicompartmental or Complex Tears

Purpose

To determine the relationship between meniscus tear morphologies, stratified by location and pattern, and knee arthroplasty rates in a commercial insurance population.

Methods

The PearlDiver database was queried for patients ≥35 years old with a meniscus tear of specified laterality and ≥2 years follow-up between 2015 and 2018. Two analyses were conducted with cohorts matched on age, sex, Charlson Comorbidity Index, obesity, osteoarthritis (OA), and treatment (meniscectomy vs conservative): one with equal-sized subgroups by tear location (medial only, lateral only, or both medial and lateral) and another by tear pattern (bucket-handle, complex, or peripheral). The rate of subsequent total knee arthroplasty (TKA) was compared between matched groups.

Results

In total, 129,987 patients (mean age: 57.8 ± 10.5 years) were matched by tear location; 1,734 patients with medial-only tears (4.0%), 1,786 with lateral-only tears (4.1%), and 2,611 with medial plus lateral tears (6.0%) underwent a TKA within 5 years (P < .001). Patients with both medial and lateral tears were 1.55-fold more likely to undergo TKA. In total, 24,213 patients (mean age: 56.0 ± 10.5 years) were matched by tear pattern; 296 patients with bucket-handle tears (3.7%), 373 with complex tears (4.6%), and 336 with peripheral tears (4.2%) underwent TKA (P = .01). Patients with complex tears were 1.29-fold more likely to undergo TKA than patients with bucket-handle tears (P = .002).

Conclusions

In matched cohorts of patients with degenerative meniscus tears, having both medial plus lateral tears conferred a 1.5-fold risk of TKA, whereas complex tears conferred a 1.3-fold risk within 5 years. Specific meniscal tear patterns and locations harbor varying risk in progressing to end-stage knee OA, and these data may help counsel patients about their likelihood of progressing to end-stage OA warranting an arthroplasty procedure.

Level of Evidence

Level III, retrospective comparative study.

A Single-Centre, Retrospective, Observational Study to Assess Safety and Functional Outcomes of Arthroscopic Meniscal Repair Using Surestitch All Inside Implant

Introduction The meniscus plays a vital role in maintaining knee stability. It acts as a shock absorber and knee filler. The incidence of meniscal tears is estimated to be 60 per 100,000 people. Due to lack of awareness among patients, only 10% of the meniscus tears were treated through partial or total meniscectomy. Recently, the concept of meniscus preservation surgery has emerged to preserve early degeneration of the knee joint. In the current retrospective study, safety and functional outcomes of arthroscopic meniscal repair surgery using Surestitch All inside implants (Sironix Arthroscopy Solutions, Healthium Medtech Limited, Bengalaru, India) were assessed. Methods Fifty-two patients who underwent arthroscopic meniscal repair surgery between January 2019 to July 2022 at Epic Hospital in Gujarat, India, were enrolled in the study. Retrospective data including demographics, injury details, surgery details, and post-surgery complications were collected from the medical records of the patients. Then, the patients were followed up telephonically to document safety and functional outcomes using patient-reported instruments such as International Knee Documentation Committee (IKDC) score, Single Assessment Numeric Evaluation (SANE) score, Tegner activity level, and Lysholm knee score. Results The recruited patients had the mean age, height, and weight of 37.56 ± 12.52 years, 167.61 ± 7.28 cm, and 75.87 ± 10.7 kgs, respectively. Seventy-one percent of patients were male and 29% were female. Majority of the patients had the routine of doing mild exercise. During pre-surgery representations, medial meniscal tear was observed in majority of patients. The mean length of the tear was 1.32 ± 0.84 cm. In addition, patients were also diagnosed with anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL) tears, and osteochondral defects. Surgeries for meniscal repair were performed using Surestitch All inside implant. In patient-reported outcomes, the mean IKDC, SANE, and Lysholm scores were 81.72 ± 14.23, 94.02 ± 13.79, and 93.32 ± 14.63, respectively. When the mean Tegner scores of pre-injury and post-surgery periods were compared, this resulted in no significant difference (p>0.05) in the activity levels of the patients. Conclusion Based on our findings, arthroscopic meniscal repair with Surestitch All inside meniscal repair implant provides satisfactory and favorable functional outcomes with no remarkable adverse events.

Earlier and More Severe Cartilage Degeneration Occurs After Meniscal Tears in Juvenile Rabbits Compared with Adults

OBJECTIVE

To compare the severity of cartilage degeneration after meniscal tears between juvenile and adult rabbits.

DESIGN

This study included 20 juvenile rabbits (2 weeks after birth) and 20 adult rabbits (6 months after birth). Meniscal tears were prepared in the anterior horn of medial menisci of right knees. Rabbits were sacrificed at 1, 3, 6, and 12 weeks postoperatively. Cartilage degenerations in the medial femoral condyle and medial tibial plateau were evaluated macroscopically and histologically. The semiquantitative assessment of cartilage degeneration was graded by macroscopic Outerbridge scoring system and histological Osteoarthritis Research Society International (OARSI) scoring system.

RESULTS

In juvenile rabbits, the morphologically intact cartilage and normal extracellular matrix architecture were observed at the first week postoperatively. Mild uneven cartilage surface and toluidine blue depletion in the medial femoral condyle were observed on histological assessment at 3 weeks postoperatively. The worsened cartilage deterioration demonstrating chondral fibrillation, prominent cell death, and glycosaminoglycan (GAG) release was observed at 6 and 12 weeks postoperatively. In adult rabbits, only mild cartilage degeneration was observed in the medial femoral condyle at 12 weeks postoperatively. The outcomes of Outerbridge and OARSI scores were consistent with the aforementioned findings in juvenile and adult rabbits.

CONCLUSIONS

Our study validated that earlier and more severe cartilage degenerations were observed in juvenile rabbits after meniscal tears compared with adult rabbits. Moreover, the post-tear cartilage degeneration demonstrated regional specificity corresponded to the tear position. However, caution is warranted when extrapolating results of animal models to humans.

Clinical significance and management of meniscal extrusion in different knee pathologies: a comprehensive review of the literature and treatment algorithm

The menisci are crescent-shaped, fibrocartilaginous structures that play a crucial role in the load transition and distribution of the contact forces along the tibiofemoral articulation. Meniscal extrusion (ME) is a radiological finding, especially in magnetic resonance imaging (MRI) scans, for which there has been growing interest in recent years. ME, in the coronary plane, is defined as the maximum distance of the most distal end of the meniscus from the border of the tibial plateau, where the tibial eminences are the most prominent, without taking into account the osteophytes. Although there is still controversy in the literature in respect of the optimal cutoff value, a threshold of 3 mm is considered significant. ME has no specific clinical finding or sign and it is encountered in many knee pathologies. It is associated with either rapidly progressive knee osteoarthritis or early onset of knee osteoarthritis and increased morbidity. In this review, we delineate the clinical significance of ME in various knee pathologies, as well as when, why and how it should be managed. To the best of our knowledge, this is the first study to elaborate on these topics.

MRI evaluation of meniscal anatomy: which parameters reach the best inter-observer concordance?

Purpose

The aim of the study is to evaluate which MRI parameters achieve the best degree of inter-individual concordance in the description of meniscal fibrocartilage, regarding its morphology, signal and position.

Materials and methods

Eighty-nine knee MRIs were included in the study, retrospectively re-evaluated by three radiologists who completed a binary report (normal/abnormal) describing the meniscus signal, position relative to the tibial plateau margin and morphology. The inter-individual concordance value was calculated using Cohen's test.

Results

We obtained different inter-individual concordance values according to the parameters considered. The concordance was poor in the description of the meniscal position relative to the tibial plateau margin (average k = 0.6); the result was comparable in the description of the meniscal morphology (average k = 0.56). The best results were obtained with the meniscal signal analysis (average k = 0.8).

Conclusion

To the best of our knowledge, there are no studies in the literature assessing the concordance between multiple readers in the description of the parameters we studied. The results we obtained suggest that the most reliable parameter for describing meniscal fibrocartilage is its signal intensity, whereas morphology and position may lead to different interpretations that are not always unequivocal.

Demographics and surgery-related complications lead to 30-day readmission rates among knee arthroscopic procedures

PURPOSE

The study objectives were (1) to evaluate risk factors related to 30-day hospital readmissions after arthroscopic knee surgeries and (2) to determine the complications that may arise from surgery.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database data from 2012 to 2017 were researched. Patients were identified using Current Procedural Terminology codes for knee arthroscopic procedures. Ordinal logistic fit regression and decision tree analysis were used to examine study objectives.

RESULTS

There were 83,083 knee arthroscopic procedures between 2012 and 2017 obtained from the National Surgical Quality Improvement Program database. The overall readmission rate was 0.87%. The complication rates were highest for synovectomy and cartilage procedures, 1.6% and 1.3% respectively. A majority of readmissions were related to the procedure (71.1%) with wound complications being the primary reason (28.2%) followed by pulmonary embolism and deep vein thrombosis, 12.7% and 10.6%, respectively. Gender and body mass index were not significant factors and age over 65 years was an independent risk factor. Wound infection, deep vein thrombosis, and pulmonary embolism were the most prevalent complications.

CONCLUSION

Healthcare professionals have a unique opportunity to modify treatment plans based on patient risk factors. For patients who are at higher risk of inferior surgical outcomes, clinicians should carefully weigh risk factors when considering surgical and non-surgical approaches.

LEVEL OF EVIDENCE

III.

Treatment of the syndrome of knee pain and meniscal tear in middle-aged and older persons: A narrative review

Objective:

Design:

Results:

Conclusion:

Inside-Out Approach to Meniscus Repair: Still the Gold Standard?

PURPOSE OF REVIEW

The purpose of this review is to provide an up-to-date summary on the current literature and trends regarding use of the inside-out approach to meniscus repair. Additionally, the paper describes the authors preferred techniques for inside-out meniscus repair utilizing posteromedial and posterolateral exposures.

RECENT FINDINGS

There has been a substantial increase in recent publications regarding meniscus repair. However, comparisons regarding the optimal repair technique have not been conclusive. Despite the recent increase in use of all-inside devices, multiple investigations with short-to-mid-term follow-up have demonstrated similar rates of meniscus healing between inside-out and all-inside repair techniques. Similarly, current literature describes comparable failure rates of around 20%. There are variations in the profile of complications, with all-inside devices having more implant-related complications and inside-out techniques with higher neurovascular injuries. Inside-out meniscus repair is a versatile, cost-effective technique that remains the gold standard for management of most meniscus tear patterns. Through a thoughtful approach, efficient suture retrieval and repair can be performed while protecting critical neurovascular structures. All-inside meniscus repair devices have increased in popularity and surgeon access, but this technique is not without limitations and comparisons to inside-out meniscus repair demonstrates equivocal outcomes.

Meniscal Tear and ACL Injury Detection Model Based on AlexNet and Iterative ReliefF

Magnetic resonance (MR) is one of the special imaging techniques used to diagnose orthopedics and traumatology. In this study, a new method has been proposed to detect highly accurate automatic meniscal tear and anterior cruciate ligament (ACL) injuries. In this study, images in three different slices were collected. These are the sagittal, coronal, and axial slices, respectively. Images taken from each slice were categorized in 3 different ways: sagittal database (sDB), coronal database (cDB), and axial database (aDB). The proposed model in the study uses deep feature extraction. In this context, deep features have been obtained by using fully-connected layers of AlexNet architecture. In the second stage of the study, the most significant features were selected using the iterative RelifF (IRF) algorithm. In the last step of the application, the features are classified by using the k-nearest neighbor (kNN) method. Three datasets were used in the study. These datasets, sDB, and cDB, have four classes and consist of 442 and 457 images, respectively. The aDB used in the study has two class labels and consists of 190 images. The model proposed within the scope of the study was applied in 3 datasets. In this context, 98.42%, 100%, and 100% accuracy values were obtained for sDB, cDB, and aDB datasets, respectively. The study results showed that the proposed method detected meniscal tear and anterior cruciate ligament (ACL) injuries with high accuracy.

On the fat saturation effect in quantitative ultrashort TE MR imaging

PURPOSE

To investigate the effect of fat saturation (FatSat) on quantitative UTE imaging of variable knee tissues on a 3T scanner.

METHODS

Three quantitative UTE imaging techniques, including the UTE multi-echo sequence for T 2 ∗ measurement, the adiabatic T_1ρ prepared UTE sequence for T_1ρ measurement, and the magnetization transfer (MT)-prepared UTE sequence for MT ratio (MTR) and macromolecular proton fraction (MMF) measurements were used in this study. Twelve samples of cartilage and twelve samples of meniscus, as well as six whole knee cadaveric specimens, were imaged with the three above-mentioned UTE sequences with and without FatSat. The difference, correlation, and agreement between the UTE measurements with and without FatSat were calculated to investigate the effects of FatSat on quantification.

RESULTS

Fat was well-suppressed using all three UTE sequences when FatSat was deployed. For the small sample study, the quantification difference ratio (QDR) values of all the measured biomarkers ranged from 0.7% to 12.6%, whereas for the whole knee joint specimen study, the QDR values ranged from 0.2% to 12.0%. Except for T_1ρ in muscle and MMF in meniscus (p > 0.05), most of the measurements showed statistical differences for T_1ρ , MTR, and MMF (p < 0.05) between FatSat and non-FatSat scans. Most of the measurements for T 2 ∗ showed no significant differences (p > 0.05). Strong correlations were found for all the biomarkers between measurements with and without FatSat.

CONCLUSION

The UTE biomarkers showed good correlation and agreement with some slight differences between the scans with and without FatSat.

Degenerative Joint Disease After Meniscectomy

The meniscus has an important role in stabilizing the knee joint and protecting the articular cartilage from shear forces. Meniscus tears are common injuries and can disrupt these protective properties, leading to an increased risk of articular cartilage damage and eventual osteoarthritis. Certain tear patterns are often treated with arthroscopic partial meniscectomy, which can effectively relieve symptoms. However, removal of meniscal tissue can also diminish the ability of the meniscus to dissipate hoop stresses, resulting in altered biomechanics of the knee joint including increased contact pressures. This makes meniscal repair an important treatment consideration whenever possible. Understanding the incidence and mechanism of osteoarthritis development after arthroscopic partial meniscectomy as it relates to different tear morphologies and other treatment alternatives (ie, meniscus repair) is important to appropriately treat meniscus tears.

Favorable Reoperation Rate at 2 Years Following Repair of Horizontal Cleavage Tears Using an All Suture-Based Technique: A Prospective, Multicenter Trial

Purpose

This prospective, multicenter trial evaluates the clinical success (as measured by reoperation rates and improvements in patient-reported outcome measures) of using circumferential compression stitches with all-suture techniques for horizontal cleavage tears (HCTs) of the meniscus.

Methods

Investigators enrolled 30 patients (mean age, 38.2 years; standard deviation, 11.1 years) aged 18 to 60 years with HCTs in the symptomatic compartment at 8 centers in the United States who underwent HCT repair with all-suture circumferential stitches using a self-retrieving all-inside suture passing device. Postoperative follow-up visits were conducted at 6 months, 1 year, and 2 years. Study outcomes included freedom from reoperation of the index meniscus repair site; knee pain and function, as measured by International Knee Documentation Committee Knee evaluation (IKDC), Knee injury and Osteoarthritis Outcome Score, Lysholm Knee Scale, and Tegner Activity Scale; and serious complications observed during the study. Minimal clinically important difference at 1 year was assessed for IKDC and Lysholm.

Results

Twenty-three patients had 2-year follow-up data available. Freedom from reoperation was 96.0% at 6 months (26/27, 91.7% at 1 year [23/25], and 82.6% at 2 years [19/23]). Significant improvement was observed in over baseline at 2 years for IKDC (36.7-82.5; P < .001), Knee injury and Osteoarthritis Outcome Score (52.2-89.3; P < .001), Lysholm (50.2-87.4; P < .001), and Tegner scores (3.3-5.3; P = .007). Minimal clinically important difference was met or exceeded for IKDC and Lysholm scores at 1 year 69.2% and 65.4% of patients, respectively. Four patients (6.7%) experienced serious complications, of which 2 were assessed as being related to the procedure.

Conclusions

Repair of HCTs using all-suture circumferential stitches placed with a self-retrieving all-inside suture passing device leads to a favorable reoperation rate (17.4%), significant improvements in clinical outcomes, and an acceptable rate of serious complications (6.7%) at 2 years, supporting the viability of this treatment approach in this indication.

Level of Evidence

Level IV, therapeutic case series.

Different effects of the lateral meniscus complete radial tear on the load distribution and transmission functions depending on the tear site

PURPOSE

To compare the effect of the lateral meniscus (LM) complete radial tear at different tear sites on the load distribution and transmission functions.

METHODS

A compressive load of 300 N was applied to the intact porcine knees (n = 30) at 15°, 30°, 60°, 90°, and 120° of flexion. The LM complete radial tears were created at the middle portion (group M), the posterior portion (group P), or the posterior root (group R) (n = 10, each group), and the same loading procedure was followed. Finally, the recorded three-dimensional paths were reproduced on the LM-removed knees. The peak contact pressure (contact area) in the lateral compartment and the calculated in situ force of the LM under the principle of superposition were compared among the four groups (intact, group M, group P, and group R).

RESULTS

At all the flexion angles, the peak contact pressure (contact area) was significantly higher (lower) after creating the LM complete radial tear as compared to that in the intact state (p < 0.01). At 120° of flexion, group R represented the highest peak contact pressure (lowest contact area), followed by group P and group M (p < 0.05). The results of the in situ force carried by the LM were similar to those of the tibiofemoral contact mechanics.

CONCLUSION

The detrimental effect of the LM complete radial tear on the load distribution and transmission functions was greatest in the posterior root tear, followed by the posterior portion tear and the middle portion tear in the deep-flexed position. Complete radial tars of the meniscus, especially at the posterior root, should be repaired to restore the biomechanical function.

Comparison between two rabbit models of posttraumatic osteoarthritis: A longitudinal tear in the medial meniscus and anterior cruciate ligament transection

Animal osteoarthritis (OA) models have been developed to understand OA progression and evaluate new OA therapies. However, individual variations in joint lesions remain a critical problem in most current OA models. We established a novel rabbit model by creating a longitudinal tear in the medial meniscus body that was reproducible and similar to posttraumatic biomechanical disturbances in human OA. New Zealand rabbits underwent surgery and were assessed for 9 weeks. The rabbits were randomized into the sham control, medial meniscal tear (MMT), and anterior cruciate ligament transection (ACLT) groups. The animals were sacrificed at 4, 6, and 9 weeks posttreatment. The knee joints were harvested for histological and gene expression assessments. Both the MMT and ACLT procedures led to time-dependent degenerative changes in the femoral condyle cartilage. At each time point, the MMT group cartilage showed more severe degenerative changes than did the ACLT group cartilage. Consistently, inflammatory cytokine and catabolic gene expression were significantly higher, and anabolic gene expression was significantly lower in the MMT group than in the ACLT group. MMT treatment caused more severe structural damage to the cartilage and higher catabolic gene expression levels than the ACLT model at each time point. The MMT model may be highly beneficial in investigating posttraumatic OA (PTOA) development, especially PTOA from a meniscal injury. The MMT model replicated key features of human PTOA, including meniscal lesions, inflammatory responses, and the progression to osteoarthritic cartilage degeneration, thereby providing an exciting new avenue for translating promising treatments to clinical practice.

Editorial Commentary: Moving the Needle: Traditional Inside-Out Meniscal Repair Has Advantages Over All-Inside Repair

Meniscus repairs for vertical, peripheral tears can be troublesome due to poor tissue quality and/or vascularity that can lead to re-rupture and subsequent removal. The gold standard, inside-out repair technique, has been challenged by all-inside devices for the benefit of improved efficiency and less morbidity but for the sake of expense and potential structural inferiority. Successful meniscus repair requires multiple components, only one of which is deciding the repair construct of choice. I feel the most important aspect will always be the indication based on tear configuration while respecting biology, because all fixation will eventually fail if the meniscus does not ultimately heal. While all-inside devices may have biomechanical properties that are similar to inside-out techniques, the burden of proof still lies on showing superiority of these devices in a clinical setting. Clinically, I still use inside-out repair techniques for large tears or for high-demand patients due to its structural integrity and small penetration of the meniscus.

Natural history of new horizontal meniscal tears in individuals at risk for and with mild to moderate osteoarthritis: data from osteoarthritis initiative

OBJECTIVES

To study the natural history of new horizontal meniscal tears and their association with progression of cartilage degeneration in individuals at risk for or with mild to moderate knee osteoarthritis over 4 years.

METHODS

Individuals who developed a new meniscal tear in the right knee over 2 years were selected from the Osteoarthritis Initiative 3T MRI studies. Knee structural changes were analyzed at the time of tear appearance (baseline), and after 4 years using a modified Whole-Organ Magnetic Resonance Imaging Score (WORMS). Meniscal tears were classified as either horizontal tears or non-horizontal tears. Individuals without a meniscal tear were 1:3 frequency matched according to BMI, gender, race, and age and served as the control group. Linear regression analysis was used to compare cross-sectional and longitudinal changes in cartilage WORMS scores.

RESULTS

Forty-one subjects developed horizontal tears, including one indiviudal who developed a tear in both menisci, and 34 developed non-horizonal tears. We found that (29/41 (70.7%)) of horizontal and (20/34 (58.8%)) of non-horizonatal tears were stable during follow-up (p = 0.281). Although knees with an incident tear had higher than controls WORMS MAX total knee scores at baseline (coef. = 0.47, p = 0.044, 95% CI = 0.01 to 0.93), there were no significant differences between the horizontal subgroup and knees without tears in overall cartilage scores at baseline and in progression over 4 years of follow-up.

CONCLUSIONS

New horizontal meniscal tears tended to be stable over 4 years and presented no significant differences in progression of cartilage degeneration when compared with knees without tears.

KEY POINTS

• Most of horizonal meniscal tears were stable over 4 years. • There were no statistically significant differences in overall progression of cartilage degenerative changes between knees with horizonal meniscal tears and control knees without tears • Horizontal tears most often occurred at the posterior horn of the medial meniscus and at the body of the lateral meniscus.

The menisci and articular cartilage: a life-long fascination

The menisci and articular cartilage of the knee have a close embryological, anatomical and functional relationship, which explains why often a pathology of one also affects the other.

Traumatic meniscus tears should be repaired, when possible, to protect the articular cartilage.

Traumatic articular cartilage lesions can be treated with success using biological treatment options such as microfracture or microdrilling, autologous chondrocyte transplantation (ACT), or osteochondral transplantation (OCT) depending on the depth and area of the lesion.

Degenerative cartilage and meniscus lesions often occur together, and osteoarthritis is already present or impending. Most degenerative meniscus lesions should be treated first conservatively and, after failed conservative treatment, should undergo arthroscopic partial meniscus resection. Degenerative cartilage lesions should also be treated conservatively initially and then surgically; thereby treating the cartilage defect itself and also maintaining the axis of the leg if necessary.

Tears of the meniscus roots are devastating injuries to the knee and should be repaired e.g. by transtibial re-fixation.

The clinical role of ‘ramp’ lesions of the meniscus is still under investigation.

Cite this article: EFORT Open Rev 2020;5:652-662. DOI: 10.1302/2058-5241.5.200016

Changes in Knee Joint Mechanics After Medial Meniscectomy Determined With a Poromechanical Model

The menisci play a vital role in the mechanical function of knee joint. Unfortunately, meniscal tears often occur. Meniscectomy is a surgical treatment for meniscal tears; however, mechanical changes in the knee joint after meniscectomy is a risk factor to osteoarthritis (OA). The objective of this study was to investigate the altered cartilage mechanics of different medial meniscectomies using a poromechanical model of the knee joint. The cartilaginous tissues were modeled as nonlinear fibril-reinforced porous materials with full saturation. The ligaments were considered as anisotropic hyperelastic and reinforced by a fibrillar collagen network. A compressive creep load of ¾ body weight was applied in full extension of the right knee during 200 s standing. Four finite element models were developed to simulate different meniscectomies of the joint using the intact model as the reference for comparison. The modeling results showed a higher load support in the lateral than medial compartment in the intact joint, and the difference in the load share between the compartments was augmented with medial meniscectomy. Similarly, the contact and fluid pressures were higher in the lateral compartment. On the other hand, the medial meniscus in the normal joint experienced more loading than the lateral one. Furthermore, the contact pressure distribution changed with creep, resulting in a load transfer between cartilage and meniscus within each compartment while the total load born by the compartment remained unchanged. This study has quantified the altered contact mechanics on the type and size of meniscectomies, which may be used to understand meniscal tear or support surgical decisions.

Patient Outcomes After Horizontal Cleavage Tear Repair: A Systematic Review

PURPOSE

To analyze the clinical outcomes and survivorship of meniscal horizontal cleavage tear (HCT) repairs with hopes of guiding future treatment decisions.

METHODS

Standard systematic review methodology was used. A comprehensive search of PubMed was conducted on June 1, 2019. The inclusion criteria were articles that were published in English, involved human subjects, and reported on at least 1 outcome after repair of HCTs. The exclusion criteria included technique guides and reviews, studies without full text available, and studies with HCT outcomes not separated from other repair groups. Effect heterogeneity was determined using the I² measure. Forest plots were created in addition to a random-effects model to show the results.

RESULTS

The systematic review yielded 19 studies evaluating 289 knees in a total of 273 patients. At most recent follow-up, there was a high probability of return to sport (93.1% [67 of 72]). Overall, 74% of patients (67 of 90) were symptom free at last follow-up, and 80% expressed satisfaction with their overall result (80 of 100). The most frequently reported subjective outcome was the Lysholm score, which improved from a preoperative study range of 48 to 79 (I² = 20.7%, P = .283) to a postoperative study range of 56 to 99 (I² = 49%, P = .081). The next most commonly reported was the International Knee Documentation Committee subjective score, which improved from a preoperative study range of 16 to 49 (I² = 47.7%, P = .125) to a postoperative study range of 72 to 95 (I² = 0%, P = .660). An overall 11.7% reported risk of reoperation was found, with most cases involving revision meniscectomy. Rates of complications beyond fixation failure were overall very low, with infrequent reports of septic arthritis and transitory dysesthesia.

CONCLUSIONS

The short- to intermediate-term results of repair of HCTs are comparable to prior studies. Survivorship is comparable to repairs of other types of meniscal tears with high rates of return to sport and low complication rates.

LEVEL OF EVIDENCE

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

Meniscal Tears: Current Understanding, Diagnosis, and Management

From once being labelled as a functionless remain of leg muscle, extensive scientific investigations in recent decades have described the meniscus as one of the most crucial structures of the knee. The incidence of meniscal injuries is on the rise and can be attributed to the increased participation of youth in sporting activities. MRI continues to be the imaging modality of choice, and surgical management is the mainstay of treatment for meniscal tears. Arthroscopic partial meniscectomy (APM) is currently the most performed orthopedic procedure around the globe. However, recent studies have conclusively shown that outcomes after an APM are no better than the outcomes after a sham/placebo surgery. Meniscal repair is now being touted as a viable and effective alternative. Meniscal repair aims to achieve meniscal healing while completely avoiding the adverse effects of partial meniscectomy. Meniscal repairs have grown in popularity over the past three decades and have proved to be a much more efficient alternative to partial meniscectomy. It is now increasingly recommended to attempt meniscal repair in all repairable tears, especially in young and physically active patients. Partial Meniscal implants have also shown excellent outcomes in long-term studies, but its efficacy in acute settings still requires further research. Research performed on various techniques of meniscal regeneration looks promising, and regenerative medicine appears to be the way forward. This review aims to critically discuss the current understanding of the meniscus, its role in biomechanics of the knee joint, and the current methods used to diagnose and manage meniscal tears.

Meniscus Repair and Regeneration: A Systematic Review from a Basic and Translational Science Perspective

Meniscus injuries are among the most common athletic injuries and result in functional impairment in the knee. Repair is crucial for pain relief and prevention of degenerative joint diseases like osteoarthritis. Current treatments, however, do not produce long-term improvements. Thus, recent research has been investigating new therapeutic options for regenerating injured meniscal tissue. This review comprehensively details the current methodologies being explored in the basic sciences to stimulate better meniscus injury repair. Furthermore, it describes how these preclinical strategies may improve current paradigms of how meniscal injuries are clinically treated through a unique and alternative perspective to traditional clinical methodology.

The Burden of Meniscus Injury in Young and Physically Active Populations

Meniscus injuries affect the young and physically active population. Although meniscus injuries are common in many sports, football, soccer, basketball, and wrestling are associated with the greatest risk. In an occupational setting, jobs requiring kneeling, squatting, and increased physical activity level have the greatest risk. Meniscus injury can be isolated to the meniscus or associated with other concomitant injuries, including anterior cruciate ligament tears and tibial plateau fractures. The frequency of meniscal repair is increasing because of a better understanding of meniscal pathophysiology, technological advancements, and a focus on meniscal preservation following injury to mitigate long-term consequences such as osteoarthritis.

Functional MRI Mapping of Human Meniscus Functionality and its Relation to Degeneration

Meniscus pathology may promote early osteoarthritis. This study assessed human meniscus functionality (i.e. its response to loading) ex vivo based on quantitative T1, T1ρ, and T2 mapping as a function of histological degeneration and loading. Forty-five meniscus samples of variable degeneration were harvested from the lateral meniscus body region of 45 patients during total knee arthroplasties. Samples underwent serial mapping on a 3.0-T MRI scanner (Achieva, Philips) using a force-controlled and torque-inducing compressive loading device. Samples were measured at three loading positions, i.e. unloaded, loaded to 2 bar (compression force 37 N) and 4 bar (69 N). Histology (Pauli classification) and biomechanics (Elastic Modulus) served as references. Based on histology, samples were trichotomized as grossly intact (n = 14), mildly degenerative (n = 16), and moderate-to-severely degenerative (n = 15) and analyzed using appropriate parametric and non-parametric tests. For T1, we found loading-induced decreases in all samples, irrespective of degeneration. For T1ρ, zonal increases in intact (apex) and decreases in degenerative samples (base) were found, while for T2, changes were ambiguous. In conclusion, force-controlled loading and serial MR imaging reveal response-to-loading patterns in meniscus. Zonal T1ρ response-to-loading patterns are most promising in differentiating degeneration, while T1 and T2 aren’t clearly related to degeneration.and may provide an imaging-based indication of functional tissue properties.

Cartilage degeneration post-meniscectomy performed for degenerative disease versus trauma: data from the Osteoarthritis Initiative

OBJECTIVE

To compare the extent of cartilage deterioration in knees with prior meniscal resection related to trauma versus knees with resection related to degenerative disease, and to compare cartilage deterioration in knees with meniscal surgery to knees without meniscal surgery, controlling for prior knee trauma.

MATERIALS AND METHODS

In this cross-sectional study, we assessed cartilage deterioration in right knees of Osteoarthritis Initiative participants: (i) with meniscal surgery due to injury (n = 79); (ii) matched control knees with a prior injury but without meniscal surgery (n = 79); (iii) with meniscal surgery but without preceding injury (n = 36); and (iv) matched control knees without meniscal surgery or prior knee injury (n = 36). Cartilage composition was measured using T2 measurements derived using semi-automatic cartilage segmentation of the right. Linear regression analysis was used to compare compartmental values of T2 between groups.

RESULTS

Comparing the mean T2 values in surgical cases with and without injury our results did not show significant differences (group i vs. iii, p > 0.05). However, knees with previous meniscal surgery showed significantly (p < 0.001) higher mean T2 values across all compartments (i.e., global T2) when compared to those without meniscal surgery for both knees with a history of trauma (group i vs. ii) and knees without prior trauma (group iii vs. iv). Similar results were obtained when analyzing the compartments separately.

CONCLUSIONS

Cartilage deterioration, assessed by T2, is similar in knees undergoing meniscal surgery after trauma and for degenerative conditions. Both groups demonstrated greater cartilage deterioration than nonsurgical knees, controlling for prior knee injury.

Reliability of meniscus tear description: a study using MRI from the Osteoarthritis Initiative

Despite being one of the most common indications for surgery, data on the types of meniscus tear that should be treated surgically are limited. Improving patient selection requires agreement on meniscus tear description. This study evaluates a simple MRI tear classification system for inter-observer agreement. Knee MRI examinations from 57 subjects from the Osteoarthritis Initiative cohort were reviewed by two sub-specialty trained, musculoskeletal radiologists. Based on two pulse sequences, each meniscus was classified by: tear or no tear; location of tear in anterior, middle or posterior third or multiple thirds; and displaced or non-displaced radial, horizontal, longitudinal or complex tear pattern. A tear was defined as signal abnormality extending to the surface on at least two images and displacement as more than 2 mm of extrusion or separation measured orthogonal to the tear plane. Kappa, weighted Kappa and percentage agreement were calculated. For the medial meniscus, Kappa and percentage agreement estimates were, respectively: the presence of tear, 0.79 and 89.5%; tear with displacement, 0.70 (weighted Kappa) and 66.0%; tear description, 0.47 and 61.4%; tear location, 0.64 and 79.0%. For the lateral meniscus, estimates were: the presence of tear, 0.75 and 89.5%; tear with displacement, 0.81 (weighted Kappa) and 86.0%; tear description, 0.56 and 78.9%; tear location, 0.74 and 87.7%. The strength of agreement between readers was moderate to substantial underscoring the challenge of meniscus tear classification.

The role of radiography and MRI for eligibility assessment in DMOAD trials of knee OA

Currently, no disease-modifying osteoarthritis drugs (DMOADs) have been approved. Past clinical trials have failed for several reasons, including the commonly applied definition of eligibility based on radiographic assessment of joint structure. In the context of precision medicine, finding the appropriate patient for a specific treatment approach will be of increasing relevance. Phenotypic stratification by use of imaging at the time of determining eligibility for clinical trials will be paramount and cannot be achieved using radiography alone. Furthermore, identification of joints at high risk of rapid progression of osteoarthritis is needed in order to enable a more efficient DMOAD trial design. In addition, joints at high risk of collapse need to be excluded at screening. The use of MRI might offer advantages over radiography in this context. Technological advances and simplified image assessment address many of the commonly perceived barriers to the application of MRI to assessment of eligibility for DMOAD clinical trials.

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.

The Meniscus in Normal and Osteoarthritic Tissues: Facing the Structure Property Challenges and Current Treatment Trends

The treatment of meniscus injuries has recently been facing a paradigm shift toward the field of tissue engineering, with the aim of regenerating damaged and diseased menisci as opposed to current treatment techniques. This review focuses on the structure and mechanics associated with the meniscus. The meniscus is defined in terms of its biological structure and composition. Biomechanics of the meniscus are discussed in detail, as an understanding of the mechanics is fundamental for the development of new meniscal treatment strategies. Key meniscal characteristics such as biological function, damage (tears), and disease are critically analyzed. The latest technologies behind meniscal repair and regeneration are assessed.

Early pre-radiographic structural pathology precedes the onset of accelerated knee osteoarthritis

BACKGROUND

Accelerated knee osteoarthritis (AKOA) is characterized by more pain, impaired physical function, and greater likelihood to receive a joint replacement compared to individuals who develop the typical gradual onset of disease. Prognostic tools are needed to determine which structural pathologies precede the development of AKOA compared to individuals without AKOA. Therefore, the purpose of this manuscript was to determine which pre-radiographic structural features precede the development of AKOA.

METHODS

The sample comprised participants in the Osteoarthritis Initiative (OAI) who had at least one radiographically normal knee at baseline (Kellgren-Lawrence [KL] grade < 1). Participants were classified into 2 groups based on radiographic progression from baseline to 48 months: AKOA (KL grade change from < 1 to > 3) and No AKOA. The index visit was the study visit when participants met criteria for AKOA or a matched timepoint for those who did not develop AKOA. Magnetic resonance (MR) images were assessed for 12 structural features at the OAI baseline, and 1 and 2 years prior to the index visit. Separate logistic regression models (i.e. OAI baseline, 1 and 2 years prior) were used to determine which pre-radiographic structural features were more likely to antedate the development of AKOA compared to individuals not developing AKOA.

RESULTS

At the OAI baseline visit, degenerative cruciate ligaments (Odds Ratio [OR] = 2.2, 95% Confidence Interval [CI] = 1.3,3.5), infrapatellar fat pad signal intensity alteration (OR = 2.0, 95%CI = 1.2,3.2), medial/lateral meniscal pathology (OR = 2.1/2.4, 95%CI = 1.3,3.4/1.5,3.8), and greater quantitative knee effusion-synovitis (OR = 2.2, 95%CI = 1.4,3.4) were more likely to antedate the development of AKOA when compared to those that did not develop AKOA. These results were similar at one and two years prior to disease onset. Additionally, medial meniscus extrusion at one year prior to disease onset (OR = 3.5, 95%CI = 2.1,6.0) increased the likelihood of developing AKOA.

CONCLUSIONS

Early ligamentous degeneration, effusion/synovitis, and meniscal pathology precede the onset of AKOA and may be prognostic biomarkers.

Degenerative meniscal tears of the knee: evaluation and management

Meniscal injuries are among the most common orthopaedic injuries seen in knee clinics. Meniscal tears can occur as a result of acute injuries or chronic degeneration. However, the exact incidence of meniscal tears is difficult to ascertain because of the high number of asymptomatic tears and the high rate of degenerative tears in patients with advanced degenerative joint disease. The management of patients with knee pain is non-operative both for degenerative meniscal tears and degenerative joint disease in its initial stages. Magnetic resonance imaging has little added value in the management of middle-aged and elderly patients with degenerative disease. Failure to respond to non-operative measures warrants orthopaedic assessment with radiographic studies and counselling on managing degenerative joint disease both non-operatively and operatively. This article focuses on assessment and management of degenerative meniscal tears.

Editorial Commentary: Preservation of the Anterior Intermeniscal Ligament Is Crucial to Meniscal Function-The Mechanical Role of the Anterior Part of the "Meniscal Belt"

The anterior intermeniscal ligament represents the most anterior part of the "meniscal belt" and potentially contributes to shock-absorbing function of the menisci and to the transmission of circumferential hoop stresses in the knee. Sectioning of the anterior intermeniscal ligament produces mechanical changes similar to those observed with meniscal extrusion, with an increase and central shift in tibiofemoral contact force.

Modern treatment of meniscal tears

The complex ultrastructure of the meniscus determines its vital functions for the knee, the lower extremity, and the body.

The most recent concise, reliable, and valid classification system for meniscal tears is the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Classification, which takes into account the subsequent parameters: tear depth, tear pattern, tear length, tear location/rim width, radial location, location according to the popliteal hiatus, and quality of the meniscal tissue.

It is the orthopaedic surgeon’s responsibility to combine clinical information, radiological images, and clinical experience in an effort to individualize management of meniscal tears, taking into account factors related to the patient and lesion.

Surgeons should strive not to operate in most cases, but to protect, repair or reconstruct, in order to prevent early development of osteoarthritis by restoring the native structure, function, and biomechanics of the meniscus.

Currently, there are three main methods of modern surgical management of meniscus tears: arthroscopic partial meniscectomy; meniscal repair with or without augmentation techniques; and meniscal reconstruction. Meniscus surgery has come a long way from the old slogan, “If it is torn, take it out!” to the currently accepted slogan, “Save the meniscus!” which has guided evolving modern treatment methods for meniscal tears. This last slogan will probably constitute the basis for newer alternative biological treatment methods in the future.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170067.

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.