Surgical treatment of complex meniscus tear and disease: state of the art

Decreasing Incidence of Partial Meniscectomy, and Increasing Incidence of Meniscus Preservation Surgery from 2010-2020 in the United States

PURPOSE

The aim of the present study was to characterize the incidence of meniscus surgery from 2010 to 2020 in the United States, using the metrics of age, sex, type of meniscus surgery, and Charlson Comorbidity Index (CCI).

METHODS

A retrospective analysis was performed using the PearlDiver national insurance claims database from 2010-2020. Meniscus surgeries were identified using Current Procedural Terminology codes. Patients were stratified by procedure type, age, biological sex, and Charlson Comorbidity Index (CCI) scores. Compound annual growth rate (CAGR) analysis and analysis of variance (ANOVA) were performed to analyze the trends and demographic variables between cohorts.

RESULTS

Of 2,053,884 meniscus surgeries, 94.7% were meniscectomies, 0.3% were open repairs, 4.9% were arthroscopic repairs, and 0.1% were meniscal transplantations. CAGR analysis displayed a 4.0% decrease per year in total meniscus surgery. For individual procedure types, the largest decrease was in meniscectomy, and the largest increase was in open repair. Patients undergoing meniscal transplantation were youngest, with the lowest CCI. Meniscectomy patients were oldest, and open repair patients had the highest average CCI. Most procedures were performed on female patients (52.4%), and patients in the 50-59-year age group (30.4%).

CONCLUSIONS

There was a sustained decrease in the incidence of total meniscus surgeries from 2010-2020. Meniscectomy was the procedure with the highest incidence, however, it showed the most significant decline in usage over the study period. Conversely, meniscal repair and transplantation procedures increased during the study period.

The Current State of Meniscus Replacements

PURPOSE OF REVIEW

The field of meniscus replacement is changing continuously, with new devices emerging and others disappearing from the market. With the current tendency to preserve the knee joint, meniscus implants may become more relevant than ever. The purpose of this review is to provide an overview of the current state of partial and total meniscus replacements that have been developed beyond the academic phase. The available clinical and pre-clinical data is evaluated, and omissions are identified.

RECENT FINDINGS

Recent systematic reviews have shown a lack of homogenous clinical data on the CMI and Actifit meniscal scaffolds, especially regarding long-term performance without concomitant surgical interventions. Clinical studies on the medial total meniscus prostheses NUsurface and Artimis are ongoing, with the NUsurface being several years ahead. New techniques for meniscus replacement are rapidly developing, including the Artimis lateral meniscus prosthesis and the MeniscoFix 3D-printed scaffold. All evaluated clinical studies point towards improved clinical outcomes after implantation of partial and total meniscus replacements. Long-term data on survival and performance is of low quality for CMI and Actifit and is unavailable yet for NUsurface and Artimis. It is of major importance that future research focuses on optimizing fixation methods and identifying the optimal treatment strategy for each patient group. New techniques for total and partial replacement of the medial and lateral meniscus will be followed with interest.

Preoperative Predictors of Patient-Reported Outcomes Following Arthroscopic Partial Meniscectomy

The purpose of this study is to evaluate the effect of patient demographics and injury characteristics on post-arthroscopic partial meniscectomy (post-APM) patient-reported outcomes (PROs). We hypothesize that the presence of high-grade (Kellgren-Lawrence grades 3-4) arthritis at any location of the knee (medial and lateral compartments, patella, trochlea), comorbidities (psychiatric history, chronic pain, diabetes, smoking, body mass index [BMI] ≥ 30), and lower scores on preoperative patient-reported measures (36-Item Short Form Health Survey [SF-36]) would predict poor outcomes after APM. We conducted a single-center prospective study of 92 patients who underwent APM surgery for associated knee pain. General demographic information and PROs were prospectively collected using SF-12, SF-36, and International Knee Documentation Committee (IKDC) surveys presurgery and at 6-month follow-up. Postsurgery outcomes were patient-reported satisfaction (yes/no) and obtaining a patient-acceptable symptom state (PASS) on IKDC. Data were analyzed with odds ratios (ORs), binomial logistic regression, and Mann-Whitney U test using IBM SPSS software. Demographic and injury characteristics that were poor prognostic indicators (had a decreased likelihood of obtaining PASS on IKDC postsurgery) included having Medicaid insurance (OR: 0.056; 0.003-1.00), chronic pain (OR: 0.106; 0.013-0.873), acute injury (OR: 0.387; 0.164-0.914), and high-grade (KL grades 3-4) medial compartment arthritis (OR: 0.412; 0.174-0.980), and preoperative SF-36 physical health score (PHS; p = 0.023) and mental health score (MHS; p = 0.006) values less than 47 and 48, respectively. Additionally, former smoking history (OR: 0.271; 0.079-0.928) showed a lower likelihood of being satisfied postsurgery. Not having psychiatric history (OR: 14.925; p < 0.001; increased likelihood of obtaining PASS on IKDC score postsurgery) and not having patellar arthritis (OR: 4.082; p = 0.025; increased likelihood of PASS on IKDC) were positive prognostic indicators. This study identifies predictive factors of poor outcomes post-APM; particularly, it highlights the usefulness of SF-36 surveys prior to APM surgery. Patients with low SF-36 score preoperatively may not find APM acceptable. Additional attention should be put on patient demographics (such as psychiatric history, chronic pain, and insurance type) and injury characteristics (presence of arthritis and acute injury) prior to performing APM. LEVEL OF EVIDENCE:  II.

Management of Meniscus Pathology with Concomitant Anterior Cruciate Ligament Injury

PURPOSE OF REVIEW

The purpose of this review is to summarize current clinical knowledge on the prevalence and types of meniscus pathology seen with concomitant anterior cruciate ligament (ACL) injury, as well as surgical techniques, clinical outcomes, and rehabilitation following operative management of these pathologies.

RECENT FINDINGS

Meniscus pathology with concomitant ACL injury is relatively common, with reports of meniscus pathology identified in 21-64% of operative ACL injuries. These concomitant injuries have been associated with increased age and body mass index. Lateral meniscus pathology is more common in acute ACL injury, while medial meniscus pathology is more typical in chronic ACL deficiency. Meniscus tear patterns associated with concomitant ACL injury include meniscus root tears, lateral meniscus oblique radial tears of the posterior horn (14%), and ramp lesions of the medial meniscus (8-24%). These meniscal pathologies with concomitant ACL injury are associated with increased rotational laxity and meniscal extrusion. There is a paucity of comparative studies to determine the optimal meniscus repair technique, as well as rehabilitation protocol, depending on specific tear pattern, location, and ACL reconstruction technique. There has been a substantial increase in recent publications demonstrating the importance of meniscus repair at the time of ACL repair or reconstruction to restore knee biomechanics and reduce the risk of progressive osteoarthritic degeneration. Through these studies, there has been a growing understanding of the meniscus tear patterns commonly identified or nearly missed during ACL reconstruction. Surgical management of meniscal pathology with concomitant ACL injury implements the same principles as utilized in the setting of isolated meniscus repair alone: anatomic reduction, biologic preparation and augmentation, and circumferential compression. Advances in repair techniques have demonstrated promising clinical outcomes, and the ability to restore and preserve the meniscus in pathologies previously deemed irreparable. Further research to determine the optimal surgical technique for specific tear patterns, as well as rehabilitation protocols for meniscus pathology with concomitant ACL injury, is warranted.

Meniscal Radial Tears Repaired With All-Inside and Inside-Out Techniques Result in Improved Clinical Outcome Scores, but Inside-Out Repairs May Be Associated With Higher Failure Rates Clinically and on Second-Look Arthroscopy: A Systematic Review

PURPOSE

To compare patient-reported outcomes (PROs), failure, and healing rates after 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 after 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 criteria and the Modified Coleman Methodology Score.

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 with 86.9 to 94.2 and 6 to 7.5, respectively, in the IO repair group. All patients exceeded published values for minimal clinically important difference 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% to 2% within the AI group, whereas no complications were reported in the IO group. No implant-related complications were reported in any study group.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and IV studies.

Biologic Augmentation of Isolated Meniscal Repair

PURPOSE OF REVIEW

The limited blood supply and intrinsic healing capacity of the meniscus contributes to suboptimal tissue regeneration following injury and surgical repair. Biologic augmentation techniques have been utilized in combination with isolated meniscal repair to improve tissue regeneration. Several innovative strategies such as Platelet-Rich Plasma (PRP), fibrin clots, mesenchymal stem cells (MSCs), bone marrow stimulation, meniscal scaffolds, and meniscal wrapping, are being explored to enhance repair outcomes. This article provides a comprehensive review of recent findings and conclusions regarding biologic augmentation techniques.

RECENT FINDINGS

Studies on PRP reveal mixed outcomes, with some suggesting benefits in reducing failure rates of isolated meniscal repair, while others question its efficacy. Fibrin clots and PRF (Platelet-rich fibrin), although promising, show inconsistent results and lack sufficient evidence for definitive conclusions. MSCs demonstrate potential in preclinical studies, but clinical trials have been limited and inconclusive. Bone marrow stimulation appears effective in certain contexts, but its broader applicability remains uncertain. Meniscal scaffolds, including CMI (Collagen Meniscal Implants) and Actifit (polyurethane scaffolds), show encouraging short- and mid-term outcomes but have not consistently surpassed traditional methods in the long term. Meniscal wrapping is infrequently studied but demonstrates positive short-term results with certain applications. The review reveals a diverse range of outcomes for biologic augmentation in meniscal repair. While certain techniques show promise, particularly in specific scenarios, the overall efficacy of these methods has yet to reach a consensus. The review underscores the necessity for standardized, high-quality research to establish the definitive effectiveness of these biologic augmentation methods.

No Differences in 2-Year Reoperation Rates for Meniscus Allograft Transplant With Concomitant Cartilage Restoration or Osteotomy: A National Database Study

PURPOSE

To investigate reoperation rates after meniscus allograft transplant (MAT), comparing rates with and without concomitant articular cartilage and osteotomy procedures using a national insurance claims database.

METHODS

We performed a retrospective cohort study of patients who underwent MAT from 2010 to 2021 with minimum 2 year follow-up using the PearlDiver database. Using Current Procedural Terminology (CPT) and International Classification of Diseases (ICD) codes, we identified patients who underwent concomitant procedures including chondroplasty or microfracture, cartilage restoration defined as osteochondral graft or autologous chondrocyte implantation (ACI), or osteotomy. Univariate logistic regressions identified risk factors for reoperation. Reoperations were classified as knee arthroplasty, interventional procedures, or diagnostic or debridement procedures.

RESULTS

750 patients were included with an average age of 29.6 years (interquartile range 21.0-36.8) and average follow-up time was 5.41 years (SD: 2.51). 90-day, 2-year, and all-time reoperation rates were 1.33%, 14.4%, and 27.6% respectively. MAT with cartilage restoration was associated with increased reoperation rate at 90 days (OR: 4.88; 95% CI: 1.38-19.27; p=.015), however there was no significant difference in reoperation rates at 2 years or to the end of follow-up. ACI had increased reoperation rates at 90 days (OR: 6.95; 95% CI: 1.45-25.96; p=.006), with no difference in reoperation rates 2 years post-operatively or to the end of follow-up. Osteochondral autograft and allograft were not associated with increased reoperation rates.

CONCLUSION

14.4% of patients in our cohort had a reoperation within 2 years of MAT. Nearly one in four patients undergoing MAT had concomitant cartilage restoration, showing that it is commonly performed on patients with articular cartilage damage. Concomitant osteochondral autograft, osteochondral allograft, chondroplasty, microfracture and osteotomy were not associated with any significant difference in reoperation rates. ACI was associated with increased reoperation rates at 90 days, but not later.

Neither All-Inside, nor Inside-Out, nor Outside-In Repair Demonstrates Superior Biomechanical Properties for Vertical Meniscal Tears: A Systematic Review of Human Cadaveric Studies

PURPOSE

To systematically review the literature regarding the biomechanical properties of different repair techniques and fixation methods for vertically oriented meniscal tears.

METHODS

Human cadaveric studies evaluating the biomechanical properties of different repair techniques for vertically oriented meniscal tears were identified using the PubMed, EMBASE, and Cumulative Index to Nursing & Allied Health databases. Primary outcomes included load to failure, displacement, stiffness, peak contact pressure, and contact area of repaired menisci. Repair techniques from included studies were reclassified into a total of 19 distinct all-inside (AI), inside-out (IO), or outside-in (OI) techniques.

RESULTS

Sixteen studies were included (420 total menisci). Contact pressure and area were restored to intact-state values across all 5 compressive load studies at low knee flexion angles but not at greater knee flexion angles (i.e., >60°). There were no significant differences in contact pressure or area between AI, IO, and OI techniques across all studies. Some studies demonstrated statistically significant advantages in tensile properties with IO techniques when compared with AI techniques, whereas others found AI techniques to be superior. No studies directly compared tensile properties of OI techniques with those of AI or IO techniques. Vertical mattress suture configurations resulted in significantly greater load to failure and decreased displacement compared with horizontal mattress configurations in 67% of studies comparing the 2 techniques. There was no difference in the rate of tissue failure in AI (66.97%), IO (60.38%), or OI (66.67%, χ2 = 0.83, P = .66) techniques.

CONCLUSIONS

Contact mechanics are reliably restored after repair of vertical meniscal tears at low flexion angles but inconsistently restored at greater flexion angles, regardless of technique. Vertical mattress configurations outperformed horizontal mattress configurations under tensile load. There are conflicting data regarding the comparison of tensile properties between AI and IO techniques. Ultimately, neither AI, IO, nor OI repair demonstrated superior biomechanical properties in the present literature.

CLINICAL RELEVANCE

Several repair techniques demonstrate favorable biomechanical properties for vertical meniscal tears under tensile and compressive loads. Neither AI, IO, nor OI repair techniques demonstrate superior biomechanical properties at this time.

Meniscocapsular release technique to reduce chronic and challenging bucket-handle meniscus tear

Several surgical procedures for the repair of bucket handle meniscus tears have been reported in the literature. However, even the most skilled surgeon can find it difficult to treat chronic and locked lesions, which typically result in meniscectomies. Therefore, a repair method for bucket-handle meniscus tears that are chronic and locked is shown, along with a case series where this procedure was used. The technique consists of a release of the joint capsule attachment to the meniscal body, which increases the mobility of the meniscus and facilitates the reduction of the injury, allowing subsequent repair through a combination of both all-inside and inside-out repair techniques. The main objective of this technique is to reduce the need for meniscectomies in difficult cases of bucket-handle meniscus tears, protect the meniscal tissue, and slow the progression of osteoarthritis in the process.

Correlation of meniscus tear type with synovial inflammation and the therapeutic potential of docosapentaenoic acid

BACKGROUND

Synovitis, characterized by inflammation of the synovial membrane, is commonly induced by meniscus tears. However, significant differences in inflammatory responses and the key inflammatory mediators of synovium induced by different types of meniscal tears remain unclear.

METHODS

Magnetic resonance imaging (MRI) was employed to identify the type of meniscus tear, and the quantification of synovial inflammation was assessed through H&E staining assay. Transcription and expression levels of IL-1β and IL-6 were evaluated using bioinformatics, ELISA, RT-qPCR, and IHC of CD68 staining assays. The therapeutic potential of Docosapentaenoic Acid (DPA) was determined through network pharmacology, ELISA, and RT-qPCR assays. The safety of DPA was assessed using colony formation and EdU staining assays.

RESULTS

The results indicate that both IL-1β and IL-6 play pivotal roles in synovitis pathogenesis, with distinct expression levels across various subtypes. Among tested meniscus tears, oblique tear and bucket handle tear induced the most severe inflammation, followed by radial tear and longitudinal tear, while horizontal tear resulted in the least inflammation. Furthermore, in synovial inflammation induced by specific meniscus tears, the anterior medial tissues exhibited significantly higher local inflammation than the anterior lateral and suprapatellar regions, highlighting the clinical relevance and practical guidance of anterior medial tissues' inflammatory levels. Additionally, we identified the essential omega-3 fatty acid DPA as a potential therapeutic agent for synovitis, demonstrating efficacy in blocking the transcription and expression of IL-1β and IL-6 with minimal side effects.

CONCLUSION

These findings provide valuable insights into the nuanced nature of synovial inflammation induced by various meniscal tear classifications and contribute to the development of new adjunctive therapeutic agents in the management of synovitis.

Adults Have a Higher Incidence of Discoid Lateral Meniscus Tears Than Children-Adults Tend to Present With Complex Tears, While Horizontal Tear Patterns Are Frequently Encountered in Children: A Systematic Review

PURPOSE

To systematically review the available literature on patients with discoid lateral meniscus (DLM) with the goal of elucidating the rates and types of meniscal tears, clinical symptoms, treatment strategies, and postoperative clinical and radiographic outcomes in adult patients compared with a pediatric population.

METHODS

A literature search was performed using the PubMed, Embase, and Scopus databases from database inception to October 2023 according to the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Level of evidence I through IV human clinical studies evaluating rate and type of meniscal tears, clinical symptoms, patient-reported outcome measures, and postoperative radiographical assessments in patients with DLM were included. Comparisons were made by age younger and older than 16 years. Study quality was assessed using the Methodological Index for Non-Randomized Studies criteria.

RESULTS

Thirteen studies comprising 1,772 adult patients (>16 years old) with DLM (n = 1,856 knees) and 8 studies conducted in 304 pediatric patients (≤16 years old, n = 353 knees) were included. The reported mean age ranged from 22.4 to 45 years (mean follow-up, 24-157.5 months) in the adult group and from 5 to 12.9 years (mean follow-up, 37-234 months) in the pediatric DLM group. Among studies that reported on tear patterns, the majority of adult (n = 553; 96.5%) and pediatric (n = 163; 71.8%) patients had tears of the DLM. Complete DLM was the predominant type of DLM in both study groups (range in adults, 49.6% to 88%; range in pediatric patients, 19%-100%) with complex (46.1%; range, 5.3%-100%) and horizontal tears (18.2%; range, 20%-37.5%) being the most frequently described tear patterns in the adult and pediatric DLM groups, respectively. Pain was the predominant reported symptom in both study groups (range in adults, 12.1%-99.3%; range in pediatric patients, 32.4%-100%). Partial meniscectomy was the most frequently reported treatment option conducted in 334 adult knees (39.5%; range, 24.2%-100%) and 66 pediatric knees (63.5%; range, 15%-100%). Overall, improved postoperative clinical outcomes were reported in both study groups; however, radiographic progression of degenerative changes after subtotal meniscectomy was noted.

CONCLUSIONS

More adult patients with DLM present with tears in the literature compared with the pediatric population. Complex and horizontal tear patterns are the most frequently reported tears in adult and pediatric patients, respectively. Pain was the most relevant symptom in both study groups. There was generally significant improvement in postoperative clinical outcome scores; partial meniscectomy, however, remains the most frequently reported treatment option and is associated with fewer degenerative changes than in subtotal meniscectomy.

LEVEL OF EVIDENCE

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

Anterior Cruciate Ligament Rupture Combined with Complete Radial Tear of the Posterior Horn of the Lateral Meniscus: Suture or Resection?

Anterior cruciate ligament (ACL) rupture often presents with a tear of the posterior horn of the lateral meniscus. There is no clear preference between ACL reconstruction with suture and resection of the meniscus. We aimed to compare the clinical efficacy of ACL reconstruction with suture versus resection in patients presenting with arthroscopic ACL rupture and radial complete tear of the posterior corner of the lateral meniscus. We retrospectively analyzed 157 patients with ACL rupture and complete radial tear of the posterior horn of the lateral meniscus. Between May 2010 and April 2015, 86 of 157 patients underwent ACL reconstruction and meniscus suture (study group, 54.78%) and 71 of 157 patients underwent ACL reconstruction and meniscus resection (control group, 45.22%) in our department. All patients were monitored over the 12 to 72-month follow-up period. The primary evaluation indices were the Lysholm scores, the International Knee Documentation Committee (IKDC) scores, pivot shift test, the Barret criteria, and magnetic resonance imaging (MRI) findings of meniscal healing. The majority of 157 patients were relatively young men (29.64 ± 7.79 years) with low body mass index (BMI) (23.79 ± 2.74). The postoperative Lysholm and IKDC scores of the two groups were significantly improved over the corresponding preoperative scores (p < 0.05). The clinical results and excellent and good rates were significantly better for the study group than for the control group (both, p < 0.05). MRI showed that the meniscal healed rate of the study group was 96.51%. There was no significant difference in BMI between subgroups for any functional outcome. For patients with ACL rupture and complete radial tear of the posterior horn of the lateral meniscus, ACL reconstruction and both simultaneous suture and resection of the posterior horn of the lateral meniscus were found to be safe and effective. There was no association between outcomes and BMI. However, the former was associated with a superior long-term clinical effect and may restore the integrity of the meniscus and is particularly recommended for young patients.

Composite Zonal Scaffolds of Collagen I/II for Meniscus Regeneration

The meniscus is divided into three zones according to its vascularity: an external vascularized red-red zone mainly comprising collagen I, a red-white interphase zone mainly comprising collagens I and II, and an internal white-white zone rich in collagen II. Known scaffolds used to treat meniscal injuries do not reflect the chemical composition of the vascular areas of the meniscus. Therefore, in this study, four composite zonal scaffolds (named A, B, C, and D) were developed and characterized; the developed scaffolds exhibited the main chemical components of the external (collagen I), interphase (collagens I/II), and internal (collagen II) zones of the meniscus. Noncomposite scaffolds were also produced (named E), which had the same shape as the composite scaffolds but were entirely made of collagen I. The composite zonal scaffolds were prepared using different concentrations of collagen I and the same concentration of collagen II and were either cross-linked with genipin or not cross-linked. Porous, biodegradable, and hydrophilic scaffolds with an expected chemical composition were obtained. Their pore size was smaller than the size reported for the meniscus substitutes; however, all scaffolds allowed the adhesion and proliferation of human adipose-derived stem cells (hADSCs) and were not cytotoxic. Data from enzymatic degradation and hADSC proliferation assays were considered for choosing the cross-linked composite scaffolds along with the collagen I scaffold and to test if composite zonal scaffolds seeded with hADSC and cultured with differentiation medium produced fibrocartilage-like tissue different from that formed in noncomposite scaffolds. After 21 days of culture, hADSCs seeded on composite scaffolds afforded an extracellular matrix with aggrecan, whereas hADSCs seeded on noncomposite collagen I scaffolds formed a matrix-like fibrocartilage without aggrecan.

Factors associated with medial meniscal extrusion in non-osteoarthritic knees with medial meniscus tears: A cross-sectional study

BACKGROUND

Medial meniscal extrusion (MME) plays an important role in the progression of knee osteoarthritis. Exploring the factors associated with MME in non-osteoarthritic knees may assist in the prevention of osteoarthritis.

OBJECTIVE

To identify the factors associated with pathologic MME in non-osteoarthritic knees with medial meniscus tears (MMTs).

DESIGN

A cross-sectional study.

PARTICIPANTS

One hundred fifty patients with non-osteoarthritic knees who underwent arthroscopic surgery for MMT. Patients were divided into a pathologic MME group (n = 54) and a control group (n = 96) based on whether a pathologic MME was present on magnetic resonance (MR) images.

SETTING

Tertiary medical institution.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The MME distance was measured on a coronal MR image obtained at the midpoint of the medial femoral condyle. An MME distance ≥3 mm was considered to indicate pathologic MME. Demographic and clinical data were collected as variables. Multivariable logistic regression analysis was performed to identify factors associated with pathologic MME.

RESULTS

After multivariable adjustment, body mass index (BMI) and the type of MMT were associated significantly with pathologic MME in the multivariable logistic regression model. Each unit higher in BMI was associated with a 13% higher risk of pathologic MME (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.01-1.28, p = .04). The odds of pathologic MME were approximately four times and three times higher for radial tears (OR 4.34, 95% CI 1.25-15.03, p = .02) and complex tears (OR 3.07, 95% CI 1.17-8.05, p = .02) than for horizontal and longitudinal tears.

CONCLUSIONS

BMI and the type of MMT were independent factors associated with pathologic MME in non-osteoarthritic knees with MMT. A higher BMI, radial tears, and complex tears were predisposed to pathologic MME.

Utility of Platelet-Rich Plasma Therapy in the Management of Meniscus Injuries: A narrative review

Menisci are crucial for knee joint functions and meniscal tears are common injuries, especially in sports activities. Platelet-rich plasma (PRP), which enhances healing, has emerged as a promising additive treatment for meniscus injuries, utilizing the regenerative properties of platelets and growth factors for improved clinical outcomes. In studies with a follow-up period of less than one year, the use of platelet-rich plasma (PRP) therapy for meniscus injuries showed significant improvements in knee symptoms and daily activity. Patients experienced enhanced outcomes in terms of pain reduction and increased sports activity, with MRI scans indicating stable meniscus conditions after six months. Studies with a follow-up of more than one year, however, did not find significant differences between groups treated with PRP and groups not treated with PRP in terms of various outcome measures, including pain and knee function. The vascularization of the menisci is vital for their proper function, and insufficient blood supply can affect healing of meniscal injuries. PRP therapy is used to enhance meniscal healing by introducing growth factors and anti-inflammatory agents. PRP therapy may enable athletes with meniscal tears to return to sports more quickly and has less rehabilitation duration. While PRP seems promising as an alternative to failed treatment or as an adjunct to treatment in the short term, its long-term effectiveness remains inconclusive. Patient preferences, commitment to therapy rehabilitation, and cost should all be considered on an individual basis.

Root Repair Has Superior Radiological and Clinical Outcomes Than Partial Meniscectomy and Nonoperative Treatment in the Management of Meniscus Root Tears: A Systematic Review

PURPOSE

To compile and analyze structural and clinical outcomes after meniscus root tear treatment as currently described in the literature.

METHODS

A review was conducted to identify studies published since 2011 on efficacy of repair, meniscectomy, and nonoperative management in the treatment of meniscus root tears. Patient cohorts were grouped into treatment categories, with medial and lateral root tears analyzed separately; data were collected on patient demographics, structural outcomes including joint space width, degree of medial meniscal extrusion, progression to total knee arthroplasty, and patient-reported outcome measures. Risk of bias was assessed using the MINORS (methodological index for non-randomized studies) criteria. Heterogeneity was measured using the I-statistic, and outcomes were summarized using forest plots without pooled means.

RESULTS

The 56 included studies comprised a total of 3,191 patients. Mean age among the included studies ranged from 24.6 to 65.6 years, whereas mean follow-up ranged from 12 to 125.9 months. Heterogeneity analysis identified significant differences between studies. Change in joint space width ranged from -2.4 to -0.6 mm (i.e., decreased space) after meniscectomy (n = 186) and -0.9 to -0.1 mm after root repair (n = 209); change in medial meniscal extrusion ranged from -0.6 to 6.5 mm after root repair (n = 521) and 0.2 to 4.2 mm after meniscectomy (n = 66); and event rate for total knee arthroplasty ranged from 0.00 to 0.22 after root repair (n = 205), 0.35 to 0.60 after meniscectomy (n = 53), and 0.27 to 0.35 after nonoperative treatment (n = 93). Root repair produced the greatest numerical increase in International Knee Documentation Committee and Lysholm scores of the 3 treatment arms. In addition, root repair improvements in Knee Injury and Osteoarthritis Outcome Score Pain (range: 22-32), Sports and Recreational Activities (range: 23-36), Quality of Life (range: 22-42), and Symptoms subscales (range: 10-19), in studies with low risk of bias.

CONCLUSIONS

The literature reporting on the treatment of meniscus root tears is heterogenous and largely limited to Level III and IV studies. Current evidence suggests root repair may be the most effective treatment strategy in lessening joint space narrowing of the knee and producing improvements in patient-reported outcomes.

LEVEL OF EVIDENCE

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

Trends in Meniscus-Related Publications in PubMed Since 1928: A Bibliometric Study

Background

As information on the meniscus accumulates in PubMed, it is possible to evaluate the trends in research on the topic over time.

Purpose

To evaluate the major trends in meniscus-related publications in PubMed from the earliest publication to the present day.

Study Design

Cross-sectional study.

Methods

PubMed was searched on January 3, 2023, using the search strategy "menisc *"[All Fields] AND ("knee"[MeSH Terms] OR "knee"[All Fields] OR "knee joint"[MeSH Terms] OR ("knee"[All Fields] AND "joint"[All Fields]) OR "knee joint"[All Fields]) AND 1900/01/01:2022/12/31[Date - Publication]. This retrieved 15,569 human and animal studies. We determined the top 10 meniscus-related publications in terms of overall citations and citations per year, as well as the top 10 authors, journals, countries, and institutions of cited publications on the meniscus. In addition, we performed word-cloud analyses based on meniscus-related terms from different periods (before 1981, before 2000, after 2005, and in the past 5 years [2018-2022]), including the year of first appearance and the number of publications featured.

Results

Since the first recorded publication on the meniscus in 1928, there was a steady growth in the number of articles until 2005, when there was an upsurge in publications from 254 in 2005 to 955 in 2022. Noyes was the author with the most citations (n = 3314), and a 2006 study by Caplan and Dennis had the most citations per year (n = 125). Arthroscopy published the most articles on the meniscus with 1118, whereas the Journal of Cellular Biochemistry had the most citations per article with 125.69. The most published countries and institutes were the United States and the Hospital for Special Surgery, respectively. Word-cloud analysis of article titles showed that "meniscectomy" had become less prominent, and "root,""ramp,""transplantation," and "slope" had become more prominent.

Conclusion

There has been an upsurge in publications on the meniscus since 2005, with word-cloud analysis indicating shifting interests in meniscus-related research.

Molecular Biology of Meniscal Healing: A Narrative Review

This review provides insights at the molecular level into the current and old methods for treating meniscal injuries. Meniscal injuries have been found to have a substantial impact on the progression of osteoarthritis. In line with the "save the meniscus" approach, meniscectomy is considered a last-resort treatment. Nevertheless, it is important to note that mechanical repair alone may not achieve the complete restoration of the meniscus. A deep understanding of the healing pathways could lead to future improvements in meniscal healing. The inclusion of cytokines and chemokines has the potential to facilitate the process of tear repair or impede the inflammatory catabolic cascade. MicroRNA (miRNA) could serve as a potential biomarker for meniscal degeneration, and RNA injections might promote collagen and growth factor production. The critical aspect of the healing process is angiogenesis within the inner zone of the meniscus. The use of collagen scaffolds and the implantation of autologous meniscus fragments have been successfully integrated into clinical settings. These findings are encouraging and underscore the need for well-designed clinical trials to explore the most effective factors that can enhance the process of meniscal repair.

A Comprehensive Review on MRI-based Knee Joint Segmentation and Analysis Techniques

Using magnetic resonance imaging (MRI) in osteoarthritis pathogenesis research has proven extremely beneficial. However, it is always challenging for both clinicians and researchers to detect morphological changes in knee joints from magnetic resonance (MR) imaging since the surrounding tissues produce identical signals in MR studies, making it difficult to distinguish between them. Segmenting the knee bone, articular cartilage and menisci from the MR images allows one to examine the complete volume of the bone, articular cartilage, and menisci. It can also be used to assess certain characteristics quantitatively. However, segmentation is a laborious and time-consuming operation that requires sufficient training to complete correctly. With the advancement of MRI technology and computational methods, researchers have developed several algorithms to automate the task of individual knee bone, articular cartilage and meniscus segmentation during the last two decades. This systematic review aims to present available fully and semi-automatic segmentation methods for knee bone, cartilage, and meniscus published in different scientific articles. This review provides a vivid description of the scientific advancements to clinicians and researchers in this field of image analysis and segmentation, which helps the development of novel automated methods for clinical applications. The review also contains the recently developed fully automated deep learning-based methods for segmentation, which not only provides better results compared to the conventional techniques but also open a new field of research in Medical Imaging.

Survivorship of 157 Arthroscopic Meniscal Allograft Transplants Using Bone Fixation at a Mean of 7 Years and Prognostic Factors Analysis

BACKGROUND

Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade.

PURPOSE

To determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (ICRS grade and Kellgren-Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs) (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale [VAS] score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty. Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed using the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure.

RESULTS

A total of 157 knees met inclusion criteria. After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as having experienced anatomic failure, and 13 (8.3%) patients experienced subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (hazard ratio [HR], 4.55; 95% CI, 1.46-14.17; P = .009) and anatomic (HR, 3.05; 95% CI, 1.34-6.92; P = .008) failure. Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR, 3.41; 95% CI, 1.05-11.01; P = .04) and anatomic (HR, 3.04; 95% CI, 1.31-7.11; P = .01) failure. High-grade cartilage damage preoperatively (HR, 10.67; 95% CI, 1.037-109.768; P = .046), patient age >25 years (HR, 5.44; 95% CI, 0.120-246.070; P = .384), and a body mass index >30 (HR, 2.24; 95% CI, 0.748-6.705; P = .149) were associated with subjective failure. PROMs including KOOS and IKDC were significantly improved at final follow-up compared with preoperative scores across all measurements (P < .005).

CONCLUSION

MAT showed good to excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent OCA transplantation are at a higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest that MAT has a lasting beneficial effect both in isolation and in complex cases with ≥1 concurrent procedures.

Surgical Management of Traumatic Meniscus Injuries

The menisci increase the contact area of load bearing in the knee and thus disperse the mechanical stress via their circumferential tensile fibers. Traumatic meniscus injuries cause mechanical symptoms in the knee, and are more prevalent amongst younger, more active patients, compared to degenerative tears amongst the elderly population. Traumatic meniscus tears typically result from the load-and-shear mechanism in the knee joint. The treatment depends on the size, location, and pattern of the tear. For non-repairable tears, partial or total meniscal resection decreases its tensile stress and increases joint contact stress, thus potentiating the risk of arthritis. A longitudinal vertical tear pattern at the peripheral third red-red zone leads to higher healing potential after repair. The postoperative rehabilitation protocols after repair range from immediate weight-bearing with no range of motion restrictions to non-weight bearing and delayed mobilization for weeks. Pediatric and adolescent patients may require special considerations due to their activity levels, or distinct pathologies such as a discoid meniscus. Further biomechanical and biologic evidence is needed to guide surgical management, postoperative rehabilitation protocols, and future technology applications for traumatic meniscus injuries.

Biomechanical Comparison of the Simple Suture Technique, Meniscal Matrix-Assisted Repair, and a Novel Meniscus Cap Suture Technique for Complex Meniscal Repair

Background

Meniscal repair is the gold standard for simple morphology tears. However, when the morphology and chronicity of the tear are less favorable, the success of the standard techniques is reduced.

Purpose/Hypothesis

To compare meniscal repair augmented by a new bioresorbable implant (Meniscus Cap) versus a traditional simple suture technique and the currently available augmented repair collagen matrix meniscus wrapping technique. It was hypothesized that the Meniscus Cap suture technique would increase ultimate failure load and less displacement during cyclic loading.

Study Design

Controlled laboratory study.

Methods

A total of 80 fresh porcine menisci were harvested. Complex tears were created in 60 menisci, and 20 intact menisci were tested as the control group. Repairs were performed on the 60 meniscal tears using 1 of the 3 techniques (20 menisci each): an inside-out H-suture group (SS), the collagen matrix wrapping technique (CMW), and the Meniscus Cap bioresorbable implant group (CM). The menisci were subjected to 500 loading cycles from 4 to 20 N at a frequency of 1 Hz, and the total displacement was recorded. Then, the specimens underwent load to failure testing at a rate of 3.15 mm/s, and the failure mode was noted.

Results

After 500 cycles of cyclic loading, there were no significant differences in displacement between the controls and CM group (0.524 vs 0.448 mm; P = .95). The displacement after the CM was significantly smaller compared with the CMW and the SS (0.448 vs 1.077 mm [P = .0009] and 0.448 vs 0.848 mm [P = .04], respectively). The ultimate load to failure was significantly greater for the controls and the CM group compared with the SS and CMW groups (controls, 1278.7 N and CM, 628.5 N vs CMW, 380.1 N and SS, 345.1 N; P < .05). The failure mode was suture breakage (suture failure) for all repairs.

Conclusion

In a porcine specimen meniscal repair model, the biomechanical properties of a novel Meniscus Cap repair technique were superior to that of the simple suture and CMW techniques.

Clinical Relevance

The results suggest that the Meniscal Cap repair technique may provide sufficient primary stability of the meniscal fixation even in the cases of complex meniscal tears.

Augmentation of a Nonanatomical Repair of a Medial Meniscus Posterior Root Tear With Centralization Using Three Knotless Anchors May Be Associated With Less Meniscal Extrusion and Better Compressive Load Distribution in Mid-Flexion Compared With Non-Anatomical Root Repair Alone in a Porcine Knee Model

PURPOSE

To investigate the biomechanics of the centralization augmentation using knotless soft anchors to a nonanatomical transtibial pull-out root repair in a porcine medial meniscus posterior root tear (MMPRT) model.

METHODS

Porcine knee joints (N = 10) were used to perform one of the following procedures: (1) intact; (2) MMPRT; (3) nonanatomical root repair; (4) nonanatomical root repair with centralization using 2 anchors: anchors were inserted at the posterior medial collateral ligament (MCL) border and 10 mm anterior to the posterior MCL border; and (5) nonanatomical root repair with centralization using 3 anchors: another anchor was placed 10 mm posterior to the posterior MCL border. Contact area on the medial meniscus (MM), contact pressure in the MM and tibial cartilage, and MM extrusion were evaluated at 30°, 45°, 60°, and 90° knee flexions under 200 N compressive force.

RESULTS

MM extrusion at the posterior MCL border was significantly reduced after root repair with centralization using 3 anchors than after root repair alone at 30° (-0.063 mm vs 1.5 mm, P = .017), 45° (0.21 mm vs 1.7 mm, P = .018), and 60° (0.78 mm vs 2.3 mm, P = .019). There were no significant differences in MM extrusion between the root repair alone and root repair with centralization using 2 anchors at all flexion angles. The contact area in the middle and posterior MM was significantly greater after centralization with 3 anchors than after root repair alone at all flexion angles (except the posterior MM at 90°). The mean contact pressure in the tibial cartilage was significantly lower after centralization with 3 anchors than after root repair at all angles.

CONCLUSIONS

Augmentation of a nonanatomical repair of a medial meniscus posterior root tear with centralization using three knotless anchors may be associated with less meniscal extrusion and better compressive load distribution between 30° and 60° flexion compared with nonanatomical root repair alone in a porcine model.

CLINICAL RELEVANCE

This biomechanical study at time zero suggests that the addition of centralization using 3 knotless anchors may reduce MM extrusion and restore the load-distributing function of the MM.

Preclinical Studies and Clinical Trials on Cell-Based Treatments for Meniscus Regeneration

This study aims at performing a thorough review of cell-based treatment strategies for meniscus regeneration in preclinical and clinical studies. The PubMed, Embase, and Web of Science databases were searched for relevant studies (both preclinical and clinical) published from the time of database construction to December 2022. Data related to cell-based therapies for in situ regeneration of the meniscus were extracted independently by two researchers. Assessment of risk of bias was performed according to the Cochrane Handbook for Systematic Reviews of Interventions. Statistical analyses based on the classification of different treatment strategies were performed. A total of 5730 articles were retrieved, of which 72 preclinical studies and 6 clinical studies were included in this review. Mesenchymal stem cells (MSCs), especially bone marrow MSCs (BMSCs), were the most commonly used cell type. Among preclinical studies, rabbit was the most commonly used animal species, partial meniscectomy was the most commonly adopted injury pattern, and 12 weeks was the most frequently chosen final time point for assessing repair outcomes. A range of natural and synthetic materials were used to aid cell delivery as scaffolds, hydrogels, or other morphologies. In clinical trials, there was large variation in the dose of cells, ranging from 16 × 106 to 150 × 106 cells with an average of 41.52 × 106 cells. The selection of treatment strategy for meniscus repair should be based on the nature of the injury. Cell-based therapies incorporating various "combination" strategies such as co-culture, composite materials, and extra stimulation may offer greater promise than single strategies for effective meniscal tissue regeneration, restoring natural meniscal anisotropy, and eventually achieving clinical translation. Impact Statement This review provides an up-to-date and comprehensive overview of preclinical and clinical studies that tested cell-based treatments for meniscus regeneration. It presents novel perspectives on studies published in the past 30 years, giving consideration to the cell sources and dose selection, delivery methods, extra stimulation, animal models and injury patterns, timing of outcome assessment, and histological and biomechanical outcomes, as well as a summary of findings for individual studies. These unique insights will help to shape future research on the repair of meniscus lesions and inform the clinical translation of new cell-based tissue engineering strategies.

Meniscectomy is associated with a higher rate of osteoarthritis compared to meniscal repair following acute tears: a meta-analysis

PURPOSE

Meniscal tears are common and may impair knee function and biomechanics. This meta-analysis compared meniscal repair versus resection in patients with symptomatic meniscal tears in terms of patient-reported outcomes measures (PROMs), joint width, surgical failure, and rate of progression to osteoarthritis (OA) at conventional radiography.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Two reviewers independently performed the analysis and a methodological quality assessment of the included studies. All the clinical investigations which compared repair versus resection of meniscal tears were accessed.

RESULTS

Data from 20 studies (31,783 patients) were collected. The mean BMI was 28.28 ± 3.2 kg/m2, and the mean age was 37.6 ± 14.0 years. The mean time elapsed from injury to surgery was 12.1 ± 10.2 months and the mean medial joint width was 4.9 ± 0.8 mm. Between studies comparability at baseline was found in age, women, BMI, time from injury to surgery and length of the follow-up, PROMs, medial joint width, and stage of OA. The resection group demonstrated a greater Lysholm score (P = 0.02). No difference was found in the International Knee Documentation Committee (P = 0.2). Nine studies reported data on the rate of failures at a mean of 63.00 ± 24.7 months. No difference was found between the two groups in terms of persistent meniscal symptoms (P = 0.8). Six studies reported data on the rate of progression to total knee arthroplasty at a mean of 48.0 ± 14.7 months follow-up. The repair group evidenced a lower rate of progression to knee arthroplasty (P = 0.0001). Six studies reported data on the rate of advanced knee OA at a mean of 48.0 ± 14.7 months of follow-up. The repair group evidenced a lower rate of advanced knee OA (P = 0.0001). No difference was found in the mean joint space width (P = 0.09).

CONCLUSION

Meniscal repair is associated with a lower progression to knee osteoarthritis at approximately six years of follow-up compared to partial meniscectomy. No difference in PROMs, medial joint width, and failures were evidenced.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Development of Poly(vinyl alcohol) Grafted Glycidyl Methacrylate/Cellulose Nanofiber Injectable Hydrogels for Meniscus Tissue Engineering

This study aimed to develop poly (vinyl alcohol) grafted glycidyl methacrylate/cellulose nanofiber (PVA-g-GMA/CNF) injectable hydrogels for meniscus tissue engineering. PVA-g-GMA is an interesting polymer for preparing cross-linking injectable hydrogels with UV radiation, but it has poor mechanical properties and low cell proliferation. In this study, CNF as a reinforcing agent was selected to improve mechanical properties and cell proliferation in PVA-g-GMA injectable hydro-gels. The effect of CNF concentration on hydrogel properties was investigated. Both PVA-g-GMA and PVA-g-GMA hydrogels incorporating 0.3, 0.5, and 0.7% (w/v) CNF can be formed by UV curing at a wavelength of 365 nm, 6 mW/cm2 for 10 min. All hydrogels showed substantial microporosity with interconnected tunnels, and a pore size diameter range of 3-68 µm. In addition, all hydrogels also showed high physicochemical properties, a gel fraction of 81-82%, porosity of 83-94%, water content of 73-87%, and water swelling of 272-652%. The water content and swelling of hydrogels were increased when CNF concentration increased. It is worth noting that the reduction of porosity in the hydrogels occurred with increasing CNF concentration. With increasing CNF concentration from 0.3% to 0.7% (w/v), the compressive strength and compressive modulus of the hydrogels significantly increased from 23 kPa to 127 kPa and 27 kPa to 130 kPa, respectively. All of the hydrogels were seeded with human cartilage stem/progenitor cells (CSPCs) and cultured for 14 days. PVA-g-GMA hydrogels incorporating 0.5% and 0.7% (w/v) CNF demonstrated a higher cell proliferation rate than PVA-g-GMA and PVA-g-GMA hydrogels incorporating 0.3% (w/v) CNF, as confirmed by MTT assay. At optimum formulation, 10%PVA-g-GMA/0.7%CNF injectable hydrogel met tissue engineering requirements, which showed excellent properties and significantly promoted cell proliferation, and has a great potential for meniscus tissue engineering application.

The meniscotibial ligament role in meniscal extrusion: a systematic review and meta-analysis

INTRODUCTION

The meniscotibial ligament (MTL) limits extrusion of the medial meniscus (MM). While meniscal extrusion may be detrimental to knee joint biomechanics, the role of the MTL in meniscal extrusion is debatable. We sought to perform a systematic review and meta-analysis to evaluate the role of the MTL and surgical techniques for MTL repair.

MATERIALS AND METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines we searched PubMed, Cochrane Library, and Embase for: (("Meniscotibial") OR ("Coronary") OR ("Ramp")) AND ("Extrusion"). After screening and applying eligibility criteria, data were extracted for MTL pathology types ("traumatic" ruptures or "induced" injuries) and meniscal extrusion. A meta-analysis evaluated the mean difference of extrusion between "intact" MTLs (native or repaired) and "injured" MTLs (induced or traumatic). We further performed a subgroup analysis between traumatic and induced MTL lesions.

RESULTS

This systematic review included six studies, which all evaluated MM extrusion. There were 74 knees with induced MTL injuries and 19 knees with traumatic MTL ruptures. Study designs were heterogenic and utilized three types of MTL repair procedures. The meta-analysis included 18 human knees and revealed that sectioning the MTL created a 2.92 mm [- 0.18 to 6.03] MM extrusion, while MTL repair decreased MM extrusion by - 2.11 mm [- 3.03 to - 1.21].

CONCLUSIONS

MTL injury may result in approximately 3 mm of MM extrusion, while repair of the MTL can decrease extrusion by 2 mm. Several novel surgical techniques exist to repair the MTL. However, studies reporting clinical outcomes of these various procedures are scarce.

Unique Anatomical Features of the Discoid Lateral Meniscus via Three-Dimensional MRI

Background The discoid lateral meniscus (DLM) is a unique anatomical variant characterized by a larger, thicker lateral meniscus. For clinical diagnosis of DLM, coronal and sagittal slices in two-dimensional (2D) MRI and arthroscopic imaging are typically employed. However, evaluating the entire shape of the DLM is challenging due to the limited views and details provided by these methods. Three-dimensional (3D) visualization with MRI offers a more comprehensive view of the entire meniscus. The purpose of this study was to demonstrate the entire shape of a DLM using 3D images and unveil its unique characteristics. Methods The study population consisted of 31 knees diagnosed with DLM through arthroscopic examination at our hospital between 2017 and 2021. This group comprised 20 males (65%) and 11 females (35%), with ages ranging from 9 to 49 years (mean age, 24.2 years). Furthermore, a control group of 43 knees without DLM was included for comparative analysis. This control group consisted of 22 males (51%) and 21 females (49%), with ages ranging from 9 to 69 years (mean age, 28.5 years). 3D images of the medial meniscus (MM) and lateral meniscus (LM) were reconstructed from 1.5T-MRI images with semi-automatic segmentation using free software. From the coordinate information, the anterior-to-posterior lengths of the MM and LM were obtained, and the medial-to-lateral anterior-to-posterior length (L/M ratio) ratio was calculated and compared with the value of the non-DLM population. Results Our method allows for the detailed delineation of the DLM's unique morphology. The DLM group exhibited a significantly smaller L/M ratio compared to the non-DLM group (DLM: 0.66±0.06, non-DLM: 0.74±0.05, p<0.001). Conclusions Reconstructed 3D images could help to demonstrate the whole morphology of DLM and reveal its unique features, in which DLM shows a significantly smaller L/M ratio as compared to non-DLM.

Using Single Peroneal Longus Tendon Graft for Segmental Meniscus Transplantation and Revision Anterior Cruciate Ligament Combined Anterolateral Reconstruction

This case report describes a new approach to segmental meniscal reconstruction using a peroneal longus autograft in a patient with recurrent traumatic medial meniscus tear and anterior cruciate ligament reconstruction (ACLR) failure. While allograft meniscal transplantation is the preferred method for treating meniscal deficiency, its high cost and various legal regulations have limited its widespread use. Autologous tendon grafts have been proposed as a substitute for allograft meniscus transplantation, but their initial results were poor, leading to little progress in this area. However, recent animal experiments and clinical studies have demonstrated promising results in using autologous tendon grafts for meniscal transplantation, including improvements in pain and quality of life for patients. Further research is needed to evaluate the effectiveness of segmental meniscal reconstruction using autologous tendon grafts, but it could potentially lead to more accessible and cost-effective treatment options for patients with meniscal deficiency.

Clinic and Home-Based Exercise with Blood Flow Restriction Resolves Thigh Muscle Atrophy after Anterior Cruciate Ligament Reconstruction with the Bone-Patellar Tendon-Bone Autograft: A Case Report

Anterior cruciate ligament reconstruction (ACLR) results in thigh muscle atrophy. Of the various interventions proposed to mitigate thigh muscle atrophy, exercise with blood flow restriction (BFR) appears safe and effective. Some literature suggests daily exposure to exercise with BFR may be indicated during the early phase of ACLR rehabilitation; this case report outlines the methodology utilized to prescribe clinic- and home-based BFR within an outpatient rehabilitation program. A 15-year-old male soccer player suffered a left knee injury involving the anterior cruciate ligament and both menisci. He underwent ACLR and completed exercise with BFR as part of his clinic- and home-based rehabilitation program, which included practical blood flow restriction during home-based rehabilitation. After 16 weeks of rehabilitation, surgical limb thigh girth values were objectively larger than the non-surgical limb (surgical, 52.25 cm; non-surgical 50 cm), as well as the multi-frequency bioelectrical impedance analysis of his lower-extremity lean body mass (surgical limb, 10.37 kg; non-surgical limb, 10.02 kg). The findings of this case report suggest that the inclusion of clinic- and home-based BFR within an outpatient rehabilitation program may be indicated to resolve thigh muscle atrophy early after ACLR.

Arthroscopic all-inside repair of challenging meniscus tears

Meniscus tears are prevalent in isolation and in combination with anterior cruciate ligament (ACL) injury. Meniscus lesions can be difficult to access and often display complex tear patterns, which result in technical challenges for the operating surgeon during surgical treatment. The aim of this video article is to demonstrate technical tips and tricks for performing all-inside repair of challenging meniscus tears. The presented techniques are indicated in young, physically active patients with symptomatic tears of the lateral and medial menisci, with or without concomitant ACL injury. The procedure is performed using standard anterolateral and anteromedial arthroscopic portals for direct visualization of complex meniscus tear patterns and all-inside instrument access. A suture passing device is used for the placement of suture loops for meniscus root repair. All-inside repair devices are used to repair the radial meniscal tears along the native circumferential fibers using a horizontal mattress suture configuration, with curved devices to achieve optimal access to challenging tears affecting the anterior and posterior aspects at the mid-body of the meniscus. Repair of radial tears at the avascular zone of the meniscus may be augmented with an autologous fibrin clot delivered using an arthroscopic cannula.

Long-term clinical results of using a posteromedial all-inside and anteromedial inside-out approach to repair unstable or irreducible bucket-handle medial meniscal tears

BACKGROUND

In irreducible bucket-handle medial meniscal tears (BHMMTs), the displaced central fragment is rotated 180° or more, meaning reduction is impossible without derotation of the tear. In chronic cases, the rotated meniscus is deformed and degenerated; thus, the issue of reproducibility and repairability arises. This study presents the clinical outcomes of chronic irreducible and unstable locked BHMMTs. Radiological outcomes were also evaluated using magnetic resonance imaging (MRI).

METHODS

This is a retrospective study of 37 patients with 11 cases of irreducible BHMMT and 26 cases of reducible but unstable chronic BHMMT who underwent operations between 2011 and 2016. Posterior arthroscopy was performed after temporary meniscus fixation using a provisional needle fixation technique. After the posterior repair with vertical mattress sutures was completed using an all-inside technique, the classic outside-in technique was performed for the anterior third of the meniscus. The Lysholm, International Knee Documentation Committee (IKDC), and Tegner activity scores were obtained from all patients before surgery and at the latest follow-up. Radiological evaluations were performed using MRI before surgery and at 6 months postoperatively.

RESULTS

Between 2011 and 2016, a total of 37 consecutive patients with irreducible and chronic BHMMTs underwent surgery. The average postoperative follow-up was 7.2 ± 1.4 years (mean ± SD). Postoperative Lysholm (89.57 ± 2.7) and IKDC (87.22 ± 3.2) scores improved significantly at the last follow-up when compared with the pre-operative scores (38.44 ± 4.5 and 23.52 ± 7.8, respectively). According to the Tegner activity scale, patients' postoperative activity levels remained unchanged compared to preoperative levels at the last follow-up.

CONCLUSION

Posterior knee arthroscopy with the all-inside posterior suture and inside-out anteromedial suture technique presented in this study yielded excellent clinical outcomes when used to repair chronic irreducible or unstable BHMMTs.

LEVEL OF EVIDENCE

Level IV.

Repair of a meniscus tear within 3 weeks after trauma significantly reduces the likelihood of a recurrent tear compared with later repairs

PURPOSE

To evaluate the potential benefit of meniscus tear repair within 3 weeks after rupture compared with more than 3 weeks after rupture.

METHODS

Ninety-one patients (95 menisci) underwent repair within 3 weeks after meniscus rupture [Group 1] and 15 patients (17 menisci) [Group 2] underwent repair more than 3 weeks after rupture. The posterior part of the ruptured meniscus was repaired with Contour Arrows^®, using a Crossbow as the insertion instrument, whereas the middle third was repaired by inserting PDS 2.0 stitches using a Meniscus Mender^® outside-in device. The patients were followed-up for a mean(SD) 8.9 years (range: 1-12 years).

RESULTS

Of the 91 patients (95 menisci) in Group 1, 88 (96.7%) healed without complications. One meniscus in one patient did not heal after 11 months, requiring resection. Two other menisci in two other patients showed partially healed tears. This part was removed while preserving most of the meniscus (failure rate: 3/91 patients: 3.3%). The other 88 patients recovered without complaints and participated in sports without restraint. Four menisci in four patients experienced a second sports-related incident, resulting in a renewed tear between 12 months and 3 years. These tears were repaired successfully again. Of the 15 patients in Group 2, 12 (80.0%) healed without complications. The ruptured part of the remaining menisci in the other three patients, (20%) was removed, with all patients remaining symptom-free until the end of follow-up. Rates of treatment failure differed significantly in these two groups (3.3% vs 20.0%, p = 0.04).

CONCLUSIONS

The overall failure rate was significantly lower in patients who underwent meniscus repair within 3 weeks than in those who underwent repair at 3 weeks (or more) after the trauma. Thus, early repair of meniscus tears is beneficial, and can prevent failure of meniscus repair surgery.

LEVEL OF EVIDENCE

III.

Autologous Synovial Mesenchymal Stem Cell Transplantation Suppresses Inflammation Caused by Synovial Harvesting and Promotes Healing in a Micro Minipig Repaired Meniscus Model

PURPOSE

Allogeneic synovial mesenchymal stem cells (MSCs) effectively promote meniscus healing in micro minipigs. We investigated the effect of autologous synovial MSC transplantation on meniscus healing in a micro minipig model of meniscus repair showing synovitis after synovial harvesting.

MATERIALS AND METHODS

Synovium was harvested from the left knee of the micro minipigs after arthrotomy and used to prepare synovial MSCs. The left medial meniscus in the avascular region was injured, repaired, and transplanted with synovial MSCs. First, synovitis was compared after 6 weeks in knees with and without synovial harvesting. Second, the repaired meniscus was compared for the autologous MSC group and the control group (in which synovium was harvested but MSCs were not transplanted) 4 weeks after transplantation.

RESULTS

Synovitis was more severe in knees subjected to synovium harvesting than in knees not subjected to harvesting. Menisci treated with autologous MSCs showed no red granulation at the tear of the meniscus, but menisci not treated with MSCS showed red granulation. Macroscopic scores, inflammatory cell infiltration scores, and matrix scores assessed by toluidine blue staining were all significantly better in the autologous MSC group than in the control group without MSCs (n = 6).

CONCLUSION

Autologous synovial MSC transplantation suppressed the inflammation caused by synovial harvesting in micro minipigs and promoted healing of the repaired meniscus.

Arthroscopic centralization reduces extrusion of the medial meniscus with posterior root defect in the ACL reconstructed knee

PURPOSE

The purpose of this study was to evaluate the effects of arthroscopic meniscal centralization reinforcement for a medial meniscus (MM) posterior root defect on knee kinematics and meniscal extrusion in the anterior cruciate ligament reconstructed (ACLR) knee. The hypothesis was that the medial meniscus centralization would reduce extrusion and anterior laxity in ACLR knee with a medical meniscal defect.

METHODS

Fourteen fresh-frozen human cadaveric knees were tested using a six-degrees-of-freedom robotic system under the following loading conditions: (a) an 89.0 N anterior tibial load, (b) 5.0 Nm internal and external rotational torques, (c) a 10.0 Nm valgus and varus loadings, and (d) a combined 7.0 Nm valgus moment and then a 5.0 Nm internal rotation torque as a static simulated pivot shift. The tested knee states included: (1) anatomic single-bundle cruciate ligament reconstruction with intact medial meniscus (MM Intact), (2) anatomic single-bundle cruciate ligament reconstruction with medial meniscus posterior root defect (MM Defect), (3) Anatomic single-bundle cruciate ligament reconstruction with medial meniscus arthroscopic centralization (MM Centralization). Medial meniscus arthroscopic centralization was performed using 1.4 mm anchors with #2 suture. The MM extrusion (MME) was measured using ultrasound under unloaded and varus loading conditions at 0° and 30° of flexion.

RESULTS

Anterior tibial translation (ATT) increased significantly with MM posterior root defect compared to MM intact at all flexion angles. With MM centralization, ATT was not significantly different from the intact meniscus at 15° and 30° of flexion. Meniscus extrusion increased significantly with the root defect compared to intact meniscus and decreased significantly with meniscal centralization compared to the root defect at both flexion angles.

CONCLUSIONS

In ACL reconstruction, cases involving irreparable medial meniscal posterior root tears, applying arthroscopic centralization for avoiding the meniscal extrusion should be considered. Clinically, in ACL reconstruction cases with irreparable medial meniscal posterior root tears, applying arthroscopic meniscal centralization for avoiding the meniscal extrusion should be considered. Meniscal centralization decreases the extrusion of the MM and offers improvements in knee laxity.

Age alone does not affect the joint survivorship after arthroscopic partial meniscectomy for degenerative medial meniscus tears: a propensity-score matched survival analysis

PURPOSE

To evaluate the effect of age itself on the joint survivorship after arthroscopic partial meniscectomy (APM) for degenerative medial meniscus tears (DMTs).

METHODS

Patients undergoing APM for DMTs during 1999-2010 were retrospectively reviewed. The inclusion criteria were as follows: (1) DMTs identified on preoperative MRI scans, (2) no definite history of trauma, and (3) follow-up duration more than 5 years. In evaluation of the joint survivorship, the endpoint was defined as conversion to arthroplasty (or realignment osteotomy) or progression to Kellgren-Lawrence grade 4. The study population was divided into older and younger groups by a cutoff age at which the difference in the joint survival rates was maximized, using a time-dependent receiver operating characteristic (ROC) curve. The two groups were then matched based on propensity scores. The joint survival rates were compared between the groups using Kaplan-Meier analysis, before and after propensity score matching (PSM).

RESULTS

A total of 633 knees were included. The cutoff age was calculated as 60 years. Before PSM, 239 knees were allocated to the older group (≥ 60 years) and 394 knees to the younger group (< 60 years). A significant difference in the joint survival rates was noted between the groups (log-rank test, p < 0.001). After PSM, 183 knees remained in each group. The difference in the survival rates was no more statistically significant (n.s.). The latest Lysholm scores of the older and the younger groups before PSM were 72.2 ± 20.8 and 79.9 ± 19.6, respectively (p < 0.001); however, the scores after PSM were 73.2 ± 20.3 and 77.4 ± 20.5, respectively (n.s.).

CONCLUSIONS

Joint survivorship after APM was affected by other factors associated with the aging process, such as cartilage status and meniscal tear pattern, rather than age itself. Advanced age should not be the only reason for precluding APM in treatment of DMTs. APM is a viable option when treating DMTs in elderly patients if adopted with caution. According to this study, a surgeon should assess the age-related factors when he considers APM in elderly patients.

LEVEL OF EVIDENCE

III.

Safety of using cultured cells with trisomy 7 in cell therapy for treating osteoarthritis

Cell therapy is a promising alternative treatment approach currently under study for osteoarthritis (OA), the most common chronic musculoskeletal disease. However, the mesenchymal stem cells (MSCs) used in cell therapy to treat OA are usually expanded in vitro to obtain sufficient numbers for transplantation, and their safety has not been fully assessed from multiple perspectives. Analysis of karyotypic abnormalities, in particular, is important to ensure the safety of cells; however, chromosomal mutations may also occur during the cell-expansion process. In addition, there have been many reports showing chromosome abnormalities, mainly trisomy 7, in the cartilage and synovium of patients with OA as well as in normal tissues. The suitability of cells with these karyotypic abnormalities as cells for cell therapy has not been evaluated. Recently, we assessed the safety of using cells with trisomy 7 from the osteoarthritic joint of a patient for transplantation, and we followed up with the patient for 5 years. This study showed analysis for copy number variant and whole-genome sequencing, compared with blood DNA from the same patient. We did not find any abnormalities in the genes regardless of trisomy 7. No side effects were observed for at least 5 years in the human clinical study. This suggests that the transplantation of cultured cells with trisomy 7 isolated from an osteoarthritic joint and transplanted into the osteoarthritic joints of the same person is not expected to cause serious adverse events. However, it is unclear what problems may arise in the case of allogeneic transplantation. Different types of risks will also exist depending on other transplantation routes, such as localization to the knee-joint only or circulation inflow and lung entrapment. In addition, since the cause of trisomy 7 occurrence remains unclear, it is necessary to clarify the mechanism of trisomy 7 in OA to perform cell therapy for OA patients in a safe manner.

•

Trisomy 7 is frequently observed in the cartilage and synovium of patients with OA.

•

MSCs with trisomy 7 did not form tumor after transplantation into mice.

•

No side effects were observed 5 years after transplantation of MSCs with trisomy 7.

In elite athletes with meniscal injuries, always repair the lateral, think about the medial! A systematic review

PURPOSE

This study aimed to evaluate and compare the time required to return to sports (RTS) after surgery, the rate of revision surgery and the time required for RTS after revision surgery in elite athletes undergoing meniscal repair or partial meniscectomy, particularly analysing the difference between medial and lateral menisci. It was hypothesised that both procedures would entail similar, high rates of RTS, with the lateral meniscus exhibiting higher potential healing postprocedure compared to the medial meniscus.

METHODS

A systematic review was conducted based on the PRISMA guidelines. Quality assessment of the systematic review was performed using the AMSTAR-2 checklist. The following search terms were browsed in the title, abstract and keyword fields: 'meniscus' or 'meniscal' AND 'tear,' 'injury' or 'lesion' AND 'professional,' 'elite' or 'high-level' AND 'athletes,' 'sports,' 'sportsman,' 'soccer,' 'basketball,' 'football' or 'handball'. The resulting measures extracted from the studies were the rate of RTS, level of RTS, complications, revision surgery and subsequent RTS, Tegner, International Knee Documentation Committee (IKDC) and Visual Analogue Scale (VAS).

RESULTS

In this study, the cohort consisted of 421 patients [415 (98.6%) men and 6 (1.4%) women] with a mean age of 23.0 ± 3.0 years. All patients were elite athletes in wrestling, baseball, soccer, rugby or handball. While 327 (77.7%) patients received partial meniscectomy at a mean age of 23.3 ± 2.6 years, 94 (22.3%) patients received meniscal repair at a mean age of 22.1 ± 4.0 years. After partial meniscectomy, 277 patients (84.7%) returned to their competitive sports activity and 256 (78.3%) returned to their pre-injury activity levels. A total of 12 (3.7%) patients required revision surgery because of persistent pain [5 (1.5%) patients], chondrolysis [2 (0.7%) patients] or both chondrolysis and lateral instability [5 (1.5%) patients]. Ten (83.3%) of the twelve patients had involvement of the lateral meniscus, whereas the location of injury was not specified in the remaining two patients. After revision surgery, all patients (100%) resumed sports activity. However, after meniscal repair, 80 (85.1%) athletes returned to their competitive sports activity and 71 (75.5%) returned to their pre-injury activity levels. A total of 16 (17.0%) patients required partial meniscectomy in cases of persistent pain or suture failure. Of these, 4 (25%) patients involved lateral and medial menisci each and 8 (50%) patients were not specified. After revision surgery, more than 80.0% of the patients (13) resumed sports activity.

CONCLUSIONS

In elite athletes with isolated meniscal injury, partial meniscectomy and meniscal suture exhibited similar rates of RTS and return to pre-injury levels. Nonetheless, athletes required more time for RTS after meniscal repair and exhibited an increased rate of revision surgery associated with a reduced rate of RTS after the subsequent surgery. For lateral meniscus tears, meniscectomy was associated with a high rate of revision surgery and risk of chondrolysis, whereas partial medial meniscectomy allowed for rapid RTS but with the potential risk of developing knee osteoarthritis over the years. The findings of this systematic review suggested a suture on the lateral meniscus in elite athletes because of the high healing potential after the procedure, the reduced risk of developing chondrolysis and the high risk of revision surgery after partial meniscectomy. Furthermore, it is important to evaluate several factors while dealing with the medial meniscus. If rapid RTS activity is needed, a hyperselective meniscectomy is recommended; otherwise, a meniscal suture is recommended to avoid accelerated osteoarthritis.

LEVEL OF EVIDENCE

Level IV.

STUDY REGISTRATION

PROSPERO-CRD42022351979 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=351979 ).

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.

Meniscal Extrusion: A Critical Analysis Review

➢

Pathologic meniscal extrusion can compromise meniscal function, leading to increased contact forces in the tibiofemoral compartment and the acceleration of osteoarthritic changes.

➢

Extrusion is typically defined as radial displacement of ≥3 mm outside the tibial border and is best diagnosed via magnetic resonance imaging, although ultrasonography has also demonstrated encouraging diagnostic utility.

➢

Surgical management of meniscal extrusion is based on the underlying etiology, the patient's symptom profile, the preexisting health of the articular surface, and the risk of future chondral injury and osteoarthritis.

Long-term follow-up of bucket-handle meniscal repairs: chondroprotective effect outweighs high failure risk

PURPOSE

Outcomes after repair of bucket-handle meniscal tears tend to be satisfying in the short-term follow-up. However, the literature is scarce regarding long-term data following repair of bucket-handle meniscal tears. The aim of this study was to assess long-term follow-up outcomes, focusing on knee osteoarthritis (OA) development and failure rate, and determine risk factors associated with failure.

METHODS

This is a retrospective cohort study, including all patients with bucket-handle tears within 4 mm of the menisco-synovial junction, who underwent meniscal repair, either isolated or combined with anterior cruciate ligament reconstruction (ACLR) between 2004 and 2015. A combination of all-inside, outside-in, and inside-out repair technique was used in all patients. Patients over 40 years old, concomitant multi-ligamentous injuries, and severe cartilage lesions documented intraoperatively were excluded. During the follow-up, a meniscus was considered healed using Barrett's criteria, while knee OA evaluation was performed according to Kellgren-Lawrence (KL) classification using standing knee radiographs. Patients were assessed preoperatively as well as postoperatively in terms of knee function using International Knee Documentation Committee (IKDC) score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

In total, the inclusion criteria were met by 66 patients. Median age at the time of operation was 21.9 years (13-39). Median follow-up was 114 (62-176) months. Total failure rate was approximately 33% at median time of 19 (6-39) months. Osteoarthritis was statistically significantly more prevalent in patients with failed repairs (mean KL score: 2.09) in comparison to patients with successful repairs (mean KL score: 0.54) p = 0.001. In addition, successful repairs were associated with higher KOOS score as compared with failed repairs (mean ± SD, 89.6 ± 4.6 vs 77.8 ± 4.9 p < 0.001), higher IKDC score (mean ± SD, 88.2 ± 5.1 vs 79.2 ± 5.2 p < 0.001), and Lysholm score (mean ± SD, 90.3 ± 5.3 vs 78.4 ± 7.8 p < 0.001). Patients with medial meniscus repair had 4.8 higher relative likelihood of failure compared to lateral meniscus [p = 0 .014, OR = 4.8 (95% Cl 1.2, 18.6)]. Patients over 16 years old had 5.7 higher relative likelihood of failure [p = 0 .016, OR = 5.7 (95% Cl 0.04, 0.85)]. Concurrent ACLR did not have a significant effect on the postoperative outcomes.

CONCLUSION

A high rate of clinical failure was observed after meniscal repair of bucket-handle tears. However, successful treatment led to lower rates of knee OA development and better knee function, approximately 10 years postoperatively. Meniscal repair of bucket-handle tears is recommended to improve knee function and prevent knee OA in young patients.

LEVEL OF EVIDENCE

III.

Meniscal Tear Management Associated with ACL Reconstruction

Meniscal lesions often occur in association with anterior cruciate ligament (ACL) tears at the moment of the injury or, secondarily, as a consequence of knee instability. Both ACL and meniscus lesions are associated with a higher risk of osteoarthritis. Adequate treatment of these lesions reduces the rate of degenerative changes in the affected knee. Meniscal tears should be addressed concomitantly with ACL reconstruction and the treatment must be oriented towards preserving the meniscal tissue anytime this is possible. Several options for approaching a meniscus tear are available. The meniscal suture should always be considered, and, if possible, meniscectomy should be the last choice. “Masterly neglect” is a valuable option in selected cases.

The crevice sign: a new indicator of meniscal instability in ACL reconstructions

PURPOSE

Meniscus preservation is key in knee surgery. The newly documented crevice sign indicates instability of the medial meniscus in ACL-deficient knees. Once the sign is visualised, it is imperative that the stability of the medial meniscus is assessed and potentially treated. It was hypothesized that there would be a strong correlation between the presence of an unstable medial meniscal tear in patients with the crevice sign in ACL-deficient knees.

METHODS

This was a multicenter prospective study carried out to evaluate the incidence of medial meniscal tears in patients with ACL-deficient knees and their correlation with a crevice sign. All patients (128) who had undergone ACL reconstruction between May 2020 and November 2020 were assessed arthroscopically for meniscal stability and divided in to two groups: stable (n = 84) and unstable (n = 44). Thereafter, the presence of the crevice sign was determined in each case.

RESULTS

The populations were comparable in terms of sex and age (Table 1). Fisher's exact test showed a significant association between the presence of the crevice sign and the instability of the medial meniscus (p < 0.001). Descriptive statistics suggest that the presence of crevice sign was associated more frequently to MM instability (38.6% vs 1.2%; p < 0.001). The specificity of this test was 98.8% and its sensitivity was 38.6%. The positive predictive value (PPV) was 94.4% and the negative predictive value (NPV) was 75.5%. Table 1 Descriptions and comparisons of internal meniscus instability of patients by presence of crevice sign Internal meniscus instability (N = 44) Internal meniscus stability (N = 84) Total (N = 128) Gender  N 44 84 128   Male 33 (75.0) 58 (69.0) 91 (71.1)   Female 11 (25.0) 26 (31.0) 37 (28.9) Fisher's exact test (n.s.) Age (years)  N 44 84 128   Mean (ET) 28.6 (9.4) 30.1 (10.2) 29.6 (9.9)   Median (IIQ) 26.5 (22.0;34.5) 27.0 (22.5;37.0) 27.0 (22.0;36.0)   [Min-Max] [14-54] [14-52] [14-54] Wilcoxon test bilateral (n.s.) Crevice sign  N 44 84 128   Absent 27 (61.4) 83 (98.8) 110 (85.9)   Present 17 (38.6) 1 (1.2) 18 (14.1) Fisher's exact test p < 0.001 CONCLUSION: The hypothesis was confirmed since medial meniscal instability was strongly correlated with the existence of the crevice sign and showed high specificity and PPV.

LEVEL OF EVIDENCE

III.

Current Reviews in Musculoskeletal Medicine: Current Controversies for Treatment of Meniscus Root Tears

PURPOSE OF REVIEW

The role of the meniscus in preserving the biomechanical function of the knee joint has been clearly defined. The hypothesis that meniscus root integrity is a prerequisite for meniscus function is supported by the development of progressive knee osteoarthritis (OA) following meniscus root tears (MRTs) treated either non-operatively or with meniscectomy. Consequently, there has been a resurgence of interest in the diagnosis and treatment of MRTs. This review examines the contemporary literature surrounding the natural history, clinical presentation, evaluation, preferred surgical repair technique and outcomes.

RECENT FINDINGS

Surgeons must have a high index of suspicion in order to diagnose a MRT because of the nonspecific clinical presentation and difficult visualization on imaging. Compared with medial MRTs that commonly occur in middle age/older patients, lateral meniscus root injuries tend to occur in younger males with lower BMIs, less cartilage degeneration, and with concomitant ligament injury. Subchondral insufficiency fractures of the knee have been found to be associated with both MRTs and following arthroscopic procedures. Meniscus root repair has demonstrated good outcomes, and acute injuries with intact cartilage should be repaired. Cartilage degeneration, BMI, and malalignment are important considerations when choosing surgical candidates. Meniscus centralization has emerged as a viable adjunct strategy aimed at correcting meniscus extrusion. Meniscus root repair results in a decreased rate of OA and arthroplasty and is economically advantageous when compared with nonoperative treatment and partial meniscectomy. The transtibial pull-through technique with the addition of centralization for the medial meniscus is associated with encouraging early results.

Degenerative Meniscus in Knee Osteoarthritis: From Pathology to Treatment

Knee osteoarthritis is a common degenerative joint disease characterized by chronic knee pain and disability in daily living. The lesion can involve the cartilage as well as the synovium, bone, ligaments, and meniscus, indicating a complicated pathology for knee osteoarthritis. The association with the meniscus has recently attracted much attention. Meniscal tears can initiate and progress knee osteoarthritis, with deleterious effects on the important roles of the meniscus in load distribution, shock absorption, and stability of the knee joint. Degenerative meniscus lesions are commonly observed in elderly people, but they have less impact on the prognosis of osteoarthritis. However, they are often accompanied by meniscal extrusion, which substantially decreases the hoop function of the meniscus and increases the risk of knee osteoarthritis. When surgical treatment is necessary, meniscal tears should be repaired to the greatest extent possible to preserve meniscus function. Long-term studies show better clinical outcomes and less degenerative osteoarthritis changes following meniscal repair than following partial meniscectomy. For meniscal extrusion repair, centralization techniques have been proposed that involve suturing the meniscus-capsule complex to the edge of the tibial plateau. Advancements in orthobiologics, such as platelet-rich plasma or stem cell therapy, have the potential to prevent the initiation or progression of osteoarthritis.

Transplantation of human autologous synovial mesenchymal stem cells with trisomy 7 into the knee joint and 5 years of follow-up

Mesenchymal stem cells (MSCs) can show trisomy 7; however, the safety of these cells has not been fully investigated. The purposes of this study were to determine the ratio of patients whose synovial MSCs were transplanted clinically, to intensively investigate MSCs with trisomy 7 from a safety perspective, and to follow up the patients for 5 years after transplantation. Synovial MSCs at passage 0 were transplanted into a knee for degenerative meniscus tears in 10 patients, and the patients were checked at 5 years. The synovial MSCs were evaluated at passages 0 to 15 by G‐bands and digital karyotyping, and trisomy 7 was found in 3 of 10 patients. In those three patients, 5% to 10% of the synovial MSCs showed trisomy 7. The mRNA expressions of representative oncogenes and genes on chromosome 7 did not differ between MSCs with and without trisomy 7. Whole‐genome sequencing and DNA methylation analysis showed similar results for MSCs with and without trisomy 7. Transplantation of human synovial MSCs with trisomy 7 into eight mouse knees did not result in tumor formation under the skin or in the knees after 8 weeks in any mouse, whereas transplanted HT1080 cells formed tumors. In vitro chondrogenic potentials were similar between MSCs with and without trisomy 7. Five‐year follow‐ups revealed no serious adverse events in all 10 human patients, including 3 who had received MSCs with trisomy 7. Overall, our findings indicated that synovial MSCs with trisomy 7 were comparable with MSCs without trisomy 7 from a safety perspective.

Ultrasound-Guided Harvesting of Synovium for Regenerative Medicine of Cartilage and Meniscus Using Synovial Mesenchymal Stem Cells

Mesenchymal stem cell (MSC) therapy for cartilage or meniscus pathologies, including osteoarthritis, requires the easy and safe collection of MSC source materials. Synovial MSCs are attractive cell sources for joint pathology because of their high proliferative and chondrogenic potential in vitro and in vivo. We developed an ultrasound-guided harvesting procedure for synovium for the regenerative medicine of cartilage and meniscus. A ∼1-cm skin incision is made at the proximal side of the patellae, and a forceps is inserted under ultrasound guidance of the suprapatellar pouch to grasp the synovium. Here, several synovium samples were retrieved and transported sterilely for culture at the cell-processing facility. After a 14-day culture of the nucleated cells, crystal violet confirmed colony formation. Cell growth was enough for MSC therapy of joint pathology (0.89 ± 0.06 × 10⁶ cells/dish). No adverse events occurred during synovium harvesting. A key advantage of this procedure is its minimal invasiveness, as synovium is harvested from a 1-cm skin incision in the knee joint. A disadvantage is the possible risk of hemostasis, as arresting bleeding at the synovial harvest site is difficult, even though the suprapatellar pouch contains no major vessels.