Finite element analysis of the knee joint stress after partial meniscectomy for meniscus horizontal cleavage tears

A nosographic and etiopathogenetic framework for subchondral bone marrow lesions in the knee: A narrative review

Purpose

Subchondral bone marrow lesions (BMLs) are present in a wide range of pathologies with different prognoses. Thus, a careful diagnosis is mandatory to address them with the proper treatment. The aim of this review was to examine BMLs aetiology and their relationship with biomechanical and biological factors, to identify BMLs and help clinicians to properly recognize and treat each of these common alterations.

Discussion

Each pathological pattern is determined by different aetiologic factors, which may act alone or synergically in determining the BML. These factors include major or minor trauma, bone tissue alterations, altered joint load distribution, coagulopathies, and hormonal alterations. This narrative review encompasses these patterns and factors providing a nosographic and etiopathogenetic framework for subchondral BMLs in the knee.

Conclusion

While the field is still heterogeneous in the definition of the nosographic framework of BMLs, there is a trend with the convergence towards a common terminology, which could help to shed more light on the complex and varied field of BMLs. Future studies should focus on better understanding the etiopathogenetic mechanisms, which can concur with the development of BML from one side, and, on the other hand, may represent targets for future treatments to address BMLs and preserve or restore the osteochondral unit.

Level of Evidence

Expert Opinion, Level V.

Management of Horizontal Cleavage Meniscus Tears

PURPOSE OF REVIEW

The management of horizontal cleavage meniscus tears (HCT) has evolved in recent years. Historically, HCTs have been treated with partial meniscectomy, but multiple studies have shown the long-term risks of development of arthritic changes in the knee following meniscectomy. These findings have renewed interest in meniscal preservation whenever possible, even in older patients not previously considered for meniscus repair. This article provides an overview of current management of horizontal cleavage meniscus tears and describes modern surgical techniques for repair of HCTs.

RECENT FINDINGS

Current research studies have continued to emphasize the benefits of meniscal preservation on long-term function. Recent data has demonstrated similar success rates following repair of HCTs compared to repair of other types of meniscus tears. Additionally, multiple recent studies have demonstrated the potential benefit of biologic augmentation in decreasing failure rate after meniscal repair. Modern surgical techniques and biologic augmentation have improved outcomes of meniscal repair. However, consideration of a patient's individual goals, activity level, and expectation are important to achieve a successful outcome regardless of treatment modality. While not every patient is a candidate for meniscal repair, current data has shown it should be considered for a growing number of patients.

Finite element analysis of the knee joint: a computational tool to analyze the combined behavior after treatment of torn ligaments and menisci in the human knee joint

Finite element analysis (FEA) is a fundamental tool that can be used in the orthopaedic world to simulate and analyze the behaviour of different surgical procedures. It is important to be aware that removing more than 20% of the meniscus could increase the shear stress in the cartilage and enlarge the risk of knee joint degeneration. In this fact, the maximal shear stress value in the medial cartilage increased up to 225% from 0.15 MPa to 0.5 MPa after medial meniscectomy. Also, meniscal root repair can improve meniscal biomechanics and potentially reduce the risk of osteoarthritis, even in cases of a loose repair. FEA has been used to better understand the biomechanical role of cruciate ligaments in the knee joint. ACLr with bone-patellar tendon-bone graft at 60 N of pretension and double-bundle PCLr were closer to that of a native knee in terms of biomechanics. The addition of a lateral extra-articular augmentation technique can reduce 50% of tibial translation and internal rotation, protecting the graft and minimizing the risk of re-rupture. Interestingly, anatomic and non-anatomic medial patellofemoral ligament reconstruction increased the pressure applied to the patellofemoral joint by increasing patellar contact pressure to 0.14 MPa at 30° of knee flexion using the semitendinosus as a graft. After all the advances in medical imaging technologies, future studies should take into consideration patient-specific data on both anatomy and mechanics, in order to better personalize the experimental model.

Effect of residual volume after surgery of the discoid lateral meniscus on tibiofemoral joint biomechanics: a finite element analysis

BACKGROUND

The purpose of this study was to investigate the influence of different residual meniscus volume on the biomechanics of tibiofemoral joint after discoid lateral meniscus (DLM) surgery by finite element analysis.

METHODS

A knee joint model was established based on CT and MRI imaging data. The DLM model was divided into five regions according to conventional meniscectomy, with volumes of 15%, 15%, 15%, 15%, 15%, and 40% for each region. Additionally, the DLM model was divided into anterior and posterior parts to obtain ten regions. The DLM was resected according to the design scheme, and together with the intact discoid meniscus, a total of 15 models were obtained. Finite element analysis was conducted to assess shear and pressure trends on the knee joint.

RESULTS

The study observed significant changes in peak shear stress and compressive stress in the lateral meniscus and lateral femur cartilage. As the meniscus volume decreased, there was an increase in these stresses. Specifically, when the meniscus volume reduced to 40%, there was a sharp increase in shear stress (302%) and compressive stress (152%) on the meniscus, as well as shear stress (195%) and compressive stress (157%) on the lateral femur cartilage. Furthermore, the model grouping results showed that preserving a higher frontal volume in the meniscus model provided better biomechanical advantages.

CONCLUSION

The use of finite element analysis has demonstrated that preserving more than 55% of the meniscus volume is necessary to prevent a significant increase in joint stress, which can potentially lead to joint degeneration. Additionally, it is crucial to preserve the front volume of the DLM in order to achieve improved knee biomechanical outcomes.