NLS-Investigation In Evaluating Knee Joints Affected by Osteoarthritis

Deformans

M.S. Petrove, L.A. Voroshilova,

V.M. Kartuzov, A.Y. Vesnin,

G.V. Derevyanko, A.P. Guglya

Introduction

Primary osteoarthritis deformans of the knee-joint is one of the most pertinent problems

in modern medicine due to its prevalence, great loss of working time and treatment

expenses. In addition, in many cases an early or differential diagnosis of the knee-joint

lesion is impeded, which complicates selecting the most efficient therapeutic and

rehabilitation measures and evaluating the patient’s disability.

Today diagnosis of knee-joint disorders comprises conventional radiography as well as

sonographic evaluation of the joints, used to examine soft tissues of the locomotorium. The

existing techniques used to examine the knee-joint allow determination of dominance of

pathological process in the joint, including degenerative ones. However, the

relationship between the intensity of patho-morphological changes and the severity and

dynamics of the process have not yet been studied.

This article aims to demonstrate the efficiency of the NLS-investigation in diagnosing

osteoarthritis deformans, especially in the early (sub-clinical) phase of the disease.

Subjects and methods

To define a normal relationship of the knee-joint anatomical structures 10 healthy persons

aged from 25 to 55 (test group) were examined. The main group consisted of 50 patients

with clinical implications of osteoarthritis deformans of knee joints in different phases. The

average duration of the disease was 7.0 + years. All patients were routinely

radiologically examined in two interpendicular planes.

The X-ray pattern analysis took into account the joint space amount of narrowing,

existence of marginal osteophytes and deformation of osseous structures with cysts and

fibrosis areas present in the sub-cartilaginous bone department.

The NLS investigation was carried out using a device equipped with a 1.5 GHz trigger sensor.

Changes in the joint capsule were evaluated in virtual shots in sagittal planes above and

below the kneecap and along the posterior surface of the joint. Frontal planes along the

lateral surfaces of the joint were used to define the exact condition of menisci, articular

cartilages and changes in the synovium.

It is traditionally believed that in the articular cartilage degenerative changes start with a

rupture of the articular matrix and degeneration of chondrosites. Therefore during the

NLS examination special attention was paid to changes in the articular cartilage. In the

36examinees of the test group the articular cartilage looked like a hyperchromous strip (1-2

points according to the Flandler’s scale). Two patients were found to have an articular

cartilage of a heterogeneous chromogenic pattern, 3-5 points in the initial phase of the

disease with small hyper-chromogenic nidi (1-2 points) present. No radiological changes in

the joints were detected for this group of patients.

In 14 (28.0%) patients in the second clinical phase of the disease the chromostructure of

the cartilage was heterogeneous and some high hyper-chromogenic structures (4-5 points)

were detected as well as hyper-chromogenic inclusions (1-3 points) of a small diameter.

In 21 (42%) examinees in the third phase of the disease the hyaline cartilage appeared as a

hyper-chromogenic strip (5-6 points).

In 10 (20.0%) patients in the same clinical phase of the disease the articular cartilage was

visualized as a distinctly hyper-chromogenic linear structure (6 points) with vertical

fissures present (4-5 points). In three patients the higher line cartilage was not visualized

mostly in the middle departments of the joint.

Depending on the phase and duration of the disease a spectral similarity (D 0.189 to

0.621) occured to the reference standard process ‘osteoarthritis deformans’

.

The X-ray pictures detected a moderate constriction and deformity of the joint space as a

primary sign of the articular cartilage distractions in 22 patients and considerable

constriction in 12 patients. Sub-cartilaginous osteophyte was very important for

osteoarthritis patagenesis. Formation of sub-cartilaginous and epiphyseal cysts were

present in the initial phases of the disease (71.0% of the patients). According to NLS-

investigation, the cysts were located sub-cartilaginously in the lateral regions of the bone,

1.0-3.0 mm deep and were as many as 4 to 12-15. Standard X-ray pictures of knee joints

displayed some changes in the sub-cartilaginous regions of the bone, like cysts and

fibrosis, only in the second phase of the disease.

A very important role in the osteoarthrosis deformans development was attributed to the

condition of the synovium and articular capsule. With the progress of the disease and

changes in its phases, a cartilaginous detritus with antigenicity formed on the articular

surfaces. That often led to the inflammation of the synovium and its fibrosis. As a result, the

synovium produced an inadequate fluid, which in turn impaired the cartilage nutrition with its

ensuing degeneration.

The synovium in healthy persons (test group) was visualized as a hyper-chromogenic

linear structure (1-2 points). The first and second phases of the disease saw a steady rise in

its chromogenic pattern in 14 (28%) patients (3-4 points). In 32 (62%) patients in the third

phase of the disease the chromogenic density of the membrane reached 4-5 points

throughout the phase with at most 3 or 6 hyper-chromogenic inclusions. In three patients

with an aggravated form of the osteoarthrosis deformans (the fourth clinical phase) the

synovium looked like a distinctly hyper-chromogenic structure (4 points) with areas of a

reduced entropic density (3-4 points).

37Changes in the membrane structure were always concomitant with synovitis with a

limited amount (mostly in the upper enstrosphe in 28.0% of the patients) or a great

amount (in all regions of the joint - in 68% of the patients) of fluid free of sediment and

additional inclusions.

Depending on the phase and extent of pathological changes in the joint affected by

osteoarthrosis a change in the joint capsule structure also took place. Only in the first

phase of the disease did the joint capsule structure remain normal.

In the second phase of the disease, especially with synovitis in evidence, the

chromostructure was assessed at 4-5 points in 14 (28%) patients and in the third and

fourth phases of the disease - up to 6 points in 34 (68%) patients.

Roentgenographic evidences of synovitis and changes in the para-articular soft tissues

were detected in some patients only in the third and fourth phases of the disease.

Thus, the analysis showed that the NLS-investigation had an advantage over

conventional roentgenologic methods in terms of early detection of degenerative changes

in the articular cartilage.

On the whole, the NLS-method sensitivity in the early phase of the disease amounted to

82%, specificity to 85% and accuracy to 86%. The sensitivity of standard radiography in two

projections was 68%, specificity 54% and accuracy 78%.

Conclusion

The extensive use of NLS-investigation of knee-joints in everyday clinical practice

enables the diagnoses of osteoarthrosis deformans in its early phases.