Meniscal Injuries: Mechanism and Classification

Association of Spontaneous Osteonecrosis of the Knee with Ipsilateral Meniscus and Posterior Root Tear: Systematic Review and Meta-analysis

Objective

The relationship between spontaneous osteonecrosis of the knee (SONK) and ipsilateral meniscus tear remains to be established, and the possible causes are clarified and summarized.

Methods

We conducted a search in Pubmed, Web of Science, Embase, and the Cochrane Library to include all English articles published from the establishment of the database until April 2023. The odds ratio (OR) and 95% confidence interval (CI) were calculated to evaluate the relationship between SONK and ipsilateral meniscus lesions.

Results

A total of 405 patients were included in eight articles, including 157 males and 248 females, with an average age of 63.94 years and an average BMI of 26.36 kg/m2. In patients with medial SONK, the prevalence of ipsilateral meniscus tear was 0.8982, 95% CI (0.7389, 0.9648), and the prevalence of ipsilateral posterior root tear was 0.6198, 95% CI (0.5169, 0.7118). The prevalence of ipsilateral meniscus tears in patients with lateral SONK was 0.2188, 95% CI (0.1150, 0.3711), and the prevalence of ipsilateral posterior root tears was 0.1667, 95% CI (0.1071, 0.2424).

Conclusions

SONK is significantly associated with meniscus or root tears, which limit meniscus function and lead to changes in the stress environment between the knee and the tibiofemur, increasing the chance of incomplete fracture. We suggest that the expression of SONK can be replaced with subchondral insufficiency fracture of the knee.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-024-01140-4.

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.

Application of smart hydrogel materials in cartilage injury repair: A systematic review and meta-analysis

OBJECTIVE

Cartilage injury is a common clinical condition, and treatment approaches have evolved over time from traditional conservative and surgical methods to regenerative repair. In this context, hydrogels, as widely used biomaterials in the field of cartilage repair, have garnered significant attention. Particularly, responsive hydrogels (also known as "smart hydrogels") have shown immense potential due to their ability to respond to various physicochemical properties and environmental changes. This paper aims to review the latest research developments of hydrogels in cartilage repair, utilizing a more systematic and comprehensive meta-analysis approach to evaluate the research status and application value of responsive hydrogels. The goal is to determine whether these materials demonstrate favorable therapeutic effects for subsequent clinical applications, thereby offering improved treatment methods for patients with cartilage injuries.

METHOD

This study employed a systematic literature search method to summarize the research progress of responsive hydrogels by retrieving literature on the subject and review studies. The search terms included "hydrogel" and "cartilage," covering data from database inception up to October 2023. The quality of the literature was independently evaluated using Review Manager v5.4 software. Quantifiable data was statistically analyzed using the R language.

RESULTS

A total of 7 articles were retrieved for further meta-analysis. In the quality assessment, the studies demonstrated reliability and accuracy. The results of the meta-analysis indicated that responsive hydrogels exhibit unique advantages and effective therapeutic outcomes in the field of cartilage repair. Subgroup analysis revealed potential influences of factors such as different types of hydrogels and animal models on treatment effects.

CONCLUSION

Responsive hydrogels show significant therapeutic effects and substantial application potential in the field of cartilage repair. This study provides strong scientific evidence for their further clinical applications and research, with the hope of promoting advancements in the treatment of cartilage injuries.

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.

Segond fracture: an indicator for increased risk of lateral meniscus injury in patients with acute anterior cruciate ligament ruptures

PURPOSE

The purpose of this study was to investigate the incidence and anatomic distribution of meniscus injury in patients who have sustained acute ACL injuries with and without concomitant Segond fracture. We hypothesized that patients who have sustained a torn ACL with a concomitant Segond fracture would have a higher incidence of lateral meniscal injuries than patients with an isolated ACL injury.

METHODS

Patients who underwent ACL reconstruction from 2012 to 2022 were retrospectively reviewed. Segond fractures were identified on knee radiographs. Inclusion criteria were age 18-40, injury during sports activity, and reconstruction within 90 days of injury. Sports activity, anatomic location of meniscus injury, and meniscus treatment were documented. Multivariable regression was used to identify predictors of meniscus injury/treatment.

RESULTS

There were 25 of 603 (4.1%) patients who had an ACL tear with concomitant Segond fracture. The incidence of lateral meniscus injury in the Segond group (72%) was significantly higher than in the non-Segond cohort (49%; p = 0.024). A significantly smaller proportion of medial meniscus injuries among patients with Segond fractures were repaired (23.1%) compared to the non-Segond group (54.2%; p = 0.043). Multivariate analysis found patients with Segond fractures to have increased odds of lateral meniscus injury (OR 2.68; [1.09, 6.60], p = 0.032) and were less likely to have medial meniscus injuries repaired (OR 0.35; [0.15, 0.81], p = 0.014). Additionally, males had increased odds of lateral meniscus injury (OR 1.54; [1.08 - 2.91], p = 0.017), which were more likely to require repair (OR 1.48; [1.02, 2.14], p = 0.038).

CONCLUSIONS

Among acute ACL injuries, the incidence of lateral meniscus injury is greater among patients with Segond fractures. Patients with Segond fracture were less likely to undergo repair of medial meniscal injuries.

Advancements in health informatics: finite element insights into medial open-wedge high tibial osteotomy and lateral meniscal tears

Knee medial compartment osteoarthritis is effectively treated by a medial open-wedge high tibial osteotomy (MOWHTO). The feasibility and safety of MOWHTO for mild lateral meniscal tears are unknown. This study examined the feasibility and safety of knee joint weight-bearing line ratio (WBLr) adjustment during MOWHTO with lateral meniscal injuries. We used a healthy adult male's lower extremities computed tomography scans and knee joint magnetic resonance imaging images to create a normal fine element (FE) model. Based on this model, we generated nine FE models for the MOWHTO operation (WBLr: 40-80%) and 15 models for various lateral meniscal injuries. A compressive load of 650N was applied to all cases to calculate the von Mises stress (VMS), and the intact lateral meniscus' maximal VMS at 77.5% WBLr was accepted as the corrective upper limit stress. Our experimental results show that mild lateral meniscal tears can withstand MOWHTO, while severe tears cannot. Our findings expand the use of MOWHTO and provide a theoretical direction for practical decisions in patients with lateral meniscal injuries.

Human-Written vs AI-Generated Texts in Orthopedic Academic Literature: Comparative Qualitative Analysis

BACKGROUND

As large language models (LLMs) are becoming increasingly integrated into different aspects of health care, questions about the implications for medical academic literature have begun to emerge. Key aspects such as authenticity in academic writing are at stake with artificial intelligence (AI) generating highly linguistically accurate and grammatically sound texts.

OBJECTIVE

The objective of this study is to compare human-written with AI-generated scientific literature in orthopedics and sports medicine.

METHODS

Five original abstracts were selected from the PubMed database. These abstracts were subsequently rewritten with the assistance of 2 LLMs with different degrees of proficiency. Subsequently, researchers with varying degrees of expertise and with different areas of specialization were asked to rank the abstracts according to linguistic and methodological parameters. Finally, researchers had to classify the articles as AI generated or human written.

RESULTS

Neither the researchers nor the AI-detection software could successfully identify the AI-generated texts. Furthermore, the criteria previously suggested in the literature did not correlate with whether the researchers deemed a text to be AI generated or whether they judged the article correctly based on these parameters.

CONCLUSIONS

The primary finding of this study was that researchers were unable to distinguish between LLM-generated and human-written texts. However, due to the small sample size, it is not possible to generalize the results of this study. As is the case with any tool used in academic research, the potential to cause harm can be mitigated by relying on the transparency and integrity of the researchers. With scientific integrity at stake, further research with a similar study design should be conducted to determine the magnitude of this issue.

Short-term transplantation effect of a tissue-engineered meniscus constructed using drilled allogeneic acellular meniscus and BMSCs

During the construction of tissue-engineered meniscus, the low porosity of extracellular matrix restricts the flow of nutrient solution and the migration and proliferation of cells, thus affecting the tissue remodeling after transplantation. In this study, the canine allogeneic meniscus was drilled first and then decellularized. The drilled tissue-engineered menisci (Drilled Allogeneic Acellular Meniscus + Bone Marrow Mesenchymal Stem Cells, BMSCs) were transplanted into the knee joints of model dogs. On the basis of ensuring the mechanical properties, the number of the porosity and the cells implanted in allogeneic acellular meniscus was significantly increased. The expression levels of glycosaminoglycans and type II collagen in the drilled tissue-engineered meniscus were also improved. It was determined that the animals in the experimental group recovered well-compared with those in the control group. The graft surface was covered with new cartilage, the retraction degree was small, and the tissue remodeling was good. The surface wear of the femoral condyle and tibial plateau cartilage was light. The results of this study showed that increasing the porosity of allogeneic meniscus by drilling could not only maintain the mechanical properties of the meniscus and increase the number of implanted cells but also promote cell proliferation and differentiation. After transplantation, the drilled tissue-engineered meniscus provided a good remodeling effect in vivo and played a positive role in repairing meniscal injury, protecting articular cartilage and restoring knee joint function.

In-Office Needle Arthroscopy with Meniscal Repair for Meniscal Lesions of the Knee

Meniscal injuries are a common cause of knee pain and are often an indication for knee arthroscopy, the most common orthopedic surgical procedure in the United States. In-office needle arthroscopy (IONA) is a described technique with the ability to diagnose and treat meniscal injuries in the office. IONA allows for diagnosis and treatment at a significantly deceased cost, with both quicker patient recovery, and improved patient satisfaction. The purpose of this technical report is to describe the technique for performing in-office needle arthroscopy for meniscal injuries of the knee, including the technique for obtaining adequate local anesthesia, proper indications, adequate visualization, and the advantages of performing these procedures in the office rather than the operating room.

Outside-in repair technique is effective in traumatic tears of the meniscus in active adults: a systematic review

PURPOSE

Meniscal injuries are common. Outside-in meniscal repair is one of the techniques advocated for the management of traumatic meniscal tears. This systematic review investigated the outcomes of the outside-in repair technique for the management of traumatic tears of the menisci. The outcomes of interest were to investigate whether PROMs improved and to evaluate the rate of complications.

METHODS

Following the 2020 PRISMA statement, in May 2023, PubMed, Web of Science, Google Scholar, and Embase were accessed with no time constraints. All the clinical investigations which reported data on meniscal repair using the outside-in technique were considered for inclusion. Only studies which reported data on acute traumatic meniscal tears in adults were considered. Only studies which reported a minimum of 24 months of follow-up were eligible.

RESULTS

Data from 458 patients were extracted. 34% (155 of 458) were women. 65% (297 of 458) of tears involved the medial meniscus. The mean operative time was 52.9 ± 13.6 min. Patients returned to their normal activities at 4.8 ± 0.8 months. At a mean of 67-month follow-up, all PROMs of interest improved: Tegner scale (P = 0.003), Lysholm score (P < 0.0001), International Knee Documentation Committee (P < 0.0001). 5.9% (27 of 458) of repairs were considered failures. Four of 186 (2.2%) patients experienced a re-injury, and 5 of 458 (1.1%) patients required re-operation.

CONCLUSION

Meniscal repair using the outside-in technique can be effectively performed to improve the quality of life and the activity level of patients with acute meniscal tears.

LEVEL OF EVIDENCE

Level IV.

Greater rate of return to play and re-injury following all-inside meniscal repair compared to the inside-out technique: a systematic review

INTRODUCTION

Inside-out and all-inside arthroscopic meniscal repairs are widely performed. However, it remains unclear which method promotes greater clinical outcomes. This study compared inside-out versus all-inside arthroscopic meniscal repair in terms of patient-reported outcome measures (PROMs), failures, return to play, and symptoms.

METHODS

This systematic review was conducted in accordance with the PRISMA guidelines. Two authors independently performed the literature search by accessing the following databases: PubMed, Google Scholar, and Scopus in February 2023. All clinical studies which investigated the outcomes of all-inside and/or inside-out meniscal repair were considered.

RESULTS

Data from 39 studies (1848 patients) were retrieved. The mean follow-up was 36.8 (9 to 120) months. The mean age of the patients was 25.8 ± 7.9 years. 28% (521 of 1848 patients) were women. No difference was found in PROMs: Tegner Activity Scale (P = 0.4), Lysholm score (P = 0.2), and International Knee Document Committee score (P = 0.4) among patients undergoing meniscal repair with all inside or inside-out techniques. All-inside repairs showed a greater rate of re-injury (P = 0.009) but also a greater rate of return to play at the pre-injury level (P = 0.0001). No difference was found in failures (P = 0.7), chronic pain (P = 0.05), reoperation (P = 0.1) between the two techniques. No difference was found in the rate of return to play (P = 0.5) and to daily activities (P = 0.1) between the two techniques.

CONCLUSION

Arthroscopic all-inside meniscal repair may be of special interest in patients with a particular interest in a fast return to sport, while, for less demanding patients, the inside-out suture technique may be recommended. High-quality comparative trials are required to validate these results in a clinical setting.

LEVEL OF EVIDENCE

Level III, systematic review.

Horizontal Cleavage Tear Meniscal Repair Using All-Inside Circumferential Compression Sutures

Horizontal cleavage meniscus tears occur more frequently in older patient populations with degenerative changes within the meniscus. Traditionally, they have been managed with nonsurgical interventions or with partial meniscectomy. As increasing evidence demonstrates the link between partial meniscectomy and progressive osteoarthritis with these types of tears, as well as worse long-term outcomes and reduced cost savings, surgical repair of horizontal cleavage meniscal tears has increased in appropriate patients. This technique article highlights the evaluation, indications, and preferred repair technique for horizontal cleavage tears in appropriately selected patients.

Corticosteroid injections 2 months before arthroscopic meniscectomy increases the rate of postoperative infections requiring surgical irrigation and debridement

PURPOSE

Consensus guidelines recommend administering a corticosteroid injection (CSI) for patients with a symptomatic degenerative meniscus lesion prior to arthroscopic partial meniscectomy (APM). A recent study found that CSI administered within 1 month prior to meniscectomy is associated with an increased risk of postoperative infection. However, infections may range in severity from superficial infections to serious infections requiring surgical interventions. The aim of this analysis was to define the rate of infections requiring surgery after APM and determine its relationship to preoperative CSI.

METHODS

The PearlDiver Mariner administrative claims database was queried for patients > 35 years old who had a CSI in the year prior to isolated APM. Rates of deep infection and infection requiring surgery within 6 months were reported between matched patients with a CSI and no injection.

RESULTS

After matching, there were 16,009 patients per group with a mean age of 59.4 years (SD = 9.6), 53.5% obesity, and 40% male. Forty-four of 113 patients who developed a postoperative deep infection went on to have a reoperation for irrigation and/or debridement (0.1% of all APM). Of these 44 patients, 30 had a preoperative CSI and 14 were controls unadjusted odds ratio (unadj-OR) if given CSI = 1.95, 95% CI 1.03-3.68, P = 0.04). Having a CSI within the month before surgery conferred a 4.56-fold increase in odds of an infection warranting surgery (95% CI 1.96-10.21, P < 0.01), whilst having a CSI 4-8 weeks before surgery conferred a 2.42-fold increase in odds (95% CI 1.04-5.42, P = 0.03). Receiving multiple CSI in the year prior to APM was associated with 5.27-fold increased odds of an infection requiring surgery (95% CI 1.19-23.27, P = 0.03), compared to having a single CSI.

CONCLUSIONS

Serious infections requiring a surgical intervention are rare after a meniscectomy, occurring in 0.1% of APMs in a matched cohort of patients over 35. Patients were five times more likely to return to the operating room for infection after APM if they had a CSI in the month before or had multiple CSIs in the year before surgery. The risk of infection was no longer significant if there was at least a 2-month interval between preoperative CSI and APM.

LEVEL OF EVIDENCE

Level III.

Biological augmentation of meniscal repair: a systematic review

PURPOSE

Orthopedic literature remains divided on the utility of biologic augmentation to optimize outcomes after isolated meniscal repair. The aim of this systematic review is to analyze the clinical outcomes and re-operation rates of biologically augmented meniscal repairs.

METHODS

PubMed, CINAHL, Cochrane, and EMBASE databases were queried in October 2020 for published literature on isolated meniscal repair with biological augmentation. Studies were assessed for quality and risk of bias by two appraisal tools. Patient demographics, meniscal tear characteristics, surgical procedure, augmentation type, post-operative rehabilitation, patient reported outcome measures, and length of follow-up were recorded, reviewed, and analyzed by two independent reviewers.

RESULTS

Of 3794 articles, 18 met inclusion criteria and yielded 537 patients who underwent biologic augmentation of meniscal repair. The biologically augmented repair rates were 5.8-27.0% with PRP augmentation, 0.0-28.5% with fibrin clot augmentation, 0.0-12.9% with marrow stimulation, and 0.0% with stem cell augmentation. One of seven studies showed lower revision rates with augmented meniscal repair compared to standard repair techniques, whereas five of seven found no benefit. Three of ten studies found significant functional improvement of biologically augmented repair versus standard repair techniques and six of ten studies found no difference. There was significant heterogeneity in methods for biologic preparation, delivery, and post-operative rehabilitation protocols.

CONCLUSION

Patients reported significant improvements in functional outcomes scores after repair with biological augmentation, though the benefit over standard repair controls is questionable. Revision rates after biologically augmented meniscal repair also appear similar to standard repair techniques. Clinicians should bear this in mind when considering biologic augmentation in the setting of meniscal repair.

LEVEL OF EVIDENCE

IV.

Post-Traumatic Osteoarthritis Assessment in Emerging and Advanced Pre-Clinical Meniscus Repair Strategies: A Review

Surgical repair of meniscus injury is intended to help alleviate pain, prevent further exacerbation of the injury, restore normal knee function, and inhibit the accelerated development of post-traumatic osteoarthritis (PTOA). Meniscus injuries that are treated poorly or left untreated are reported to significantly increase the risk of PTOA in patients. Current surgical approaches for the treatment of meniscus injuries do not eliminate the risk of accelerated PTOA development. Through recent efforts by scientists to develop innovative and more effective meniscus repair strategies, the use of biologics, allografts, and scaffolds have come into the forefront in pre-clinical investigations. However, gauging the extent to which these (and other) approaches inhibit the development of PTOA in the knee joint is often overlooked, yet an important consideration for determining the overall efficacy of potential treatments. In this review, we catalog recent advancements in pre-clinical therapies for meniscus injuries and discuss the assessment methodologies that are used for gauging the success of these treatments based on their effect on PTOA severity. Methodologies include histopathological evaluation of cartilage, radiographic evaluation of the knee, analysis of knee function, and quantification of OA predictive biomarkers. Lastly, we analyze the prevalence of these methodologies using a systemic PubMed® search for original scientific journal articles published in the last 3-years. We indexed 37 meniscus repair/replacement studies conducted in live animal models. Overall, our findings show that approximately 75% of these studies have performed at least one assessment for PTOA following meniscus injury repair. Out of this, 84% studies have reported an improvement in PTOA resulting from treatment.