NLS Investigation in Evaluating Knee Joint Conditions Associated with Osteoarthritis

1. Introduction

Primary osteoarthritis of the knee is a common joint disorder that presents significant challenges in modern medicine due to its prevalence, impact on working capacity, and associated treatment costs. Early identification and assessment of knee joint changes are important considerations in the management of this condition.

Conventional examinations of knee joint disorders include radiography and ultrasonography, which are used to evaluate bone structures and soft tissues. These methods help identify degenerative changes and assess the structural condition of the joint.

This article presents a study investigating the application of non-linear system (NLS) examination in evaluating knee osteoarthritis, with particular attention to structural changes observed at different stages of the disease.

2. Subjects and Methods

The study included 60 participants divided into two groups.

The control group consisted of 10 healthy individuals aged between 25 and 55 years. They were examined to establish reference observations of normal knee joint structures.

The main group consisted of 50 patients with clinical manifestations of knee osteoarthritis at different stages of the disease. The average disease duration was 7.0 ± 3.0 years.

2.1 Radiographic Examination

All patients underwent routine radiographic examinations in two perpendicular projections.

The radiographic images were evaluated according to the following structural characteristics:

• Degree of joint space narrowing.
• Presence of marginal osteophytes.
• Deformation of bone structures.
• Presence of cystic changes and areas of fibrosis in the subchondral bone.

2.2 NLS Examination

NLS examination was performed using an Oberon device equipped with a 1.5 GHz trigger sensor.

Changes in the joint capsule were evaluated using virtual images in sagittal planes above and below the patella, as well as along the posterior surface of the knee joint.

Frontal scanning planes along the lateral surfaces of the joint were used to examine the menisci, articular cartilage, and synovial membrane.

Particular attention was given to the reported structural appearance of the articular cartilage during NLS examination.

3. Results

3.1 Articular Cartilage Examination

In the healthy control group, the articular cartilage was described as a homogeneous structure.

In two patients in the initial stage of the disease, the articular cartilage demonstrated a heterogeneous structural appearance with small areas of increased chromogenic intensity. No radiographic changes in the knee joints were detected in these patients.

In 14 patients (28%) in the second clinical stage, the cartilage demonstrated a heterogeneous structural appearance with prominent areas of increased chromogenic intensity.

In 21 patients (42%) in the third stage, the hyaline cartilage was described as having a distinctly altered structural appearance.

In another 10 patients (20%) in the same clinical stage, the articular cartilage appeared as a linear structure with reported vertical fissures.

In three patients, the cartilage line was not visualized, mainly in the central regions of the joint.

3.2 Radiographic Findings and Subchondral Changes

Radiographic examination revealed moderate joint space narrowing and deformation in 22 patients. Considerable joint space narrowing was observed in 12 patients.

The study also reported subchondral and epiphyseal changes in patients with knee osteoarthritis. According to the original observations, these changes were identified through NLS examination, including in patients in the initial stages of the disease.

Conventional radiographic examinations demonstrated changes in the subchondral bone, including cystic and fibrotic areas, mainly in patients at the second stage of the disease.

3.3 Synovial Membrane Examination

The study also examined the structural appearance of the synovial membrane in patients with different stages of knee osteoarthritis.

In healthy individuals, the synovial membrane was described as a relatively uniform linear structure.

In patients in the first and second stages of the disease, changes in the structural appearance of the synovial membrane were reported.

In patients in the third stage, more pronounced structural changes and areas of increased chromogenic intensity were described.

In three patients with advanced osteoarthritis, classified as the fourth clinical stage, the synovial membrane demonstrated more pronounced structural changes.

3.4 Synovitis and Joint Fluid

Changes in the synovial membrane were accompanied by observations described in the original study as synovitis.

The study reported different amounts of joint fluid in the examined patients, with variations in its distribution within the knee joint.

3.5 Joint Capsule Examination

The study also evaluated the structural appearance of the joint capsule at different clinical stages of osteoarthritis.

In the first stage of the disease, the joint capsule was described as maintaining its normal structural appearance.

In the second stage, changes in the joint capsule structure were reported, particularly in patients with accompanying synovitis.

More pronounced structural changes were described in patients in the third and fourth stages of the disease.

Conventional radiographic examinations identified signs of synovitis and changes in the surrounding soft tissues mainly in patients with advanced disease.

4. Discussion

The study examined different structural features of the knee joint using NLS investigation and conventional radiographic methods.

The reported NLS observations included changes in the articular cartilage, subchondral bone, synovial membrane, and joint capsule across different clinical stages of knee osteoarthritis.

Some structural changes were reported in patients whose radiographic examinations did not show obvious abnormalities.

5. Conclusion

The study explored the application of NLS investigation in evaluating knee joint conditions associated with osteoarthritis.

The reported observations covered several joint structures, including articular cartilage, subchondral bone, the synovial membrane, and the joint capsule.

The findings provide a description of how NLS examination was applied in the original study to observe knee joint changes at different stages of osteoarthritis.

Further independent clinical research would be necessary to establish the diagnostic value and clinical applications of this examination method.