Osteoarthritis diagnosis: arthroscopy

To date, the treatment of osteoarthritis is mainly aimed at improving symptoms, primarily on the elimination of pain syndrome. In the process of current research, preparations are being developed that can change the course of osteoarthritis: prevent, delay the development of changes in the joints or even cause their reverse development. Carrying out such studies requires standardized and reproducible assessments of changes in the joints for a clear evaluation of the results of treatment. This applies primarily to assessing the number, integrity and / or quality of the articular cartilage.

In recent years, apoplexy has been considered as a method of early diagnosis of osteoarthritis, since it allows one to detect the above changes in cartilage even in the absence of radiographic signs of the disease. With respect to, for example, the knee joint, this method provides a straight line involving enlargement, visualization of the six joint surfaces, the technique being more sensitive than radiography or MRI for cartilage damage. The advantages of arthroscopy served as the basis for considering this method as the "gold standard" for assessing the condition of articular cartilage. Some authors, with these advantages in mind, call the technique "chondroscopy." Direct visualization makes it possible to evaluate the synovial membrane, the severity of the synovitis, and also biopsy, which is especially important for the anterior sections of the knee joint, the changes in which are often fragmentary in osteoarthritis.

The main problems of arthroscopy to date include the following: its invasive nature, insufficiently developed standardized assessment systems of chondropathies for osteoarthritis, as well as recommendations for unifying the visualization of the surfaces of articular cartilage.

[1], [2], [3], [4], [5], [6]

Methods of arthroscopy

Arthroscopy performed for therapeutic purposes is often performed under general or spinal anesthesia, while diagnostic arthroscopy can be performed under local (subcutaneous or intra-articular) anesthesia, which makes the procedure more safe, affordable and inexpensive. E. Eriksson and co-authors (1986), when comparing the results of different methods of arthroscopy, found that about 77% of patients underwent local or spinal anesthesia, while under the general procedure, 97% were satisfied. PM Blackburn and co-authors (1994) found a good tolerability of arthroscopy performed under local anesthesia comparable to MRI of knee joints in all 16 patients examined, 8 of them preferred arthroscopy, 2 - MPT, and 6 talked about equally good tolerability of both procedures .

In a prospective study conducted by X. Ayral et al (1993), 84 patients underwent chondroscopy under local anesthesia, with tolerability rated as "good" 62% of patients, "very good" - 28%. 25% of these patients did not feel pain at all, and 75% noted minor pain during or immediately after the procedure. Daily motor activity after arthroscopy was difficult in 79% of patients (up to 1 day - in 44%, up to 2 days - in 55%, up to 1 week - in 79%). By the end of the first month after chondroscopy, 82% of patients reported improvement.

JB McGintyn RA Matza (1978) evaluated the diagnostic accuracy of arthroscopy performed under general or local anesthesia by means of post-orthoscopic imaging with arthrotomy. It was found that arthroscopy was somewhat more accurate if conducted under local anesthesia (95%) than under general anesthesia (91%). However, it should be emphasized that carrying out arthroscopy under local anesthesia requires more preparation, even for experienced arthroscopists.

Arthroscope with a small glass lens

Arthroscopy of the knee joint is often performed using an arthroscope with a 4 mm glass lens and a 5.5 mm trocar. In some patients with ligament contractures or residual muscle tension (due to local anesthesia), the posterior part of the tibio-femoral joint may not be available for a standard arthroscope (4 mm). Arthroscope with a 2.7-mm lens has a field of view comparable to a standard arthroscope, and in most cases allows you to examine all parts of the joint. The constant irrigation of the knee joint, provided by a 2.7-mm arthroscope, is sufficient to clean the joint of blood and various particles and provide a clear field for visualization. Technically, a 25-30 ° viewing angle provides a wide and better view. Fiber-optic arthroscopes of smaller diameter (1.8 mm) can be inserted into the joint through the puncture hole rather than through the incision, but they have a number of drawbacks: a smaller field of view, a duller and grainy image, due to the transfer of the image along the fibers and the worst irrigation, as well as a tendency to inflection and breakage of optical fibers, which often leads to obtaining only a direct image. According to these authors, the sensitivity of these arthroscopes compared with the standard in the detection of cartilage defects is 89%, and the synovial membrane - 71%.

The results of a prospective, open, uncontrolled study conducted by H. Ayral and co-authors (1993) indicate an improvement in well-being in 82% of patients 1 month after chondroscopy. It is believed that the lavage of the joint cavity, carried out during the procedure (usually about 1 liter of isotonic sodium chloride solution) provides a clinical improvement from the manifestations of the joint syndrome, which is confirmed by the data of controlled studies, and neutralizes the potential harm of this invasive procedure.

[7],

Arthroscopic assessment of the severity of cartilage damage in osteoarthritis

[8], [9], [10], [11], [12]

Traditional classification systems

To assess the dynamics of articular cartilage damage in osteoarthritis, especially under the influence of ongoing treatment, quantitative assessment systems are required, providing for the three main parameters of these lesions: depth, size and localization. To date, many different arthroscopic classification systems are known.

Some of the classification systems take into account only the depth of the joint cartilage lesions and give qualitative information about the cartilage surface, not providing a quantitative approach to the recording of cartilage lesions. In other systems, a combination of the depth and size of the most severe chondropathy of the joint surface is taken into account for one descriptive category, but there are many discrepancies. A brief description of the classification systems is given below.

The classification system proposed by RE Outerbridge (1961) divides the cartilage damage by the degree:

• I degree - softening and swelling of the cartilage without cracks (true chondromalacia);
• II - fragmentation of cartilage and the formation of cracks with a diameter of 0.5 inches or less;
• III - fragmentation of cartilage and the formation of cracks with a diameter of more than 0.5 inches;
• IV - cartilage erosion involving the subchondral bone.

It is seen that the II and III degree have the same depth and for them the size is described, whereas I and IV degrees are not evaluated in detail. In addition, the size of the cracks (degrees II and III) is not a constant value.

RP Ficat and co-authors (1979) divided the cartilage lesions into closed and open chondromalacia, with closed chondromalacia (I degree) representing true chondromalacia (softening and swelling), and open (2nd degree) - open (with the presence of cracks) chondropathy. According to this system, a lesion corresponding to the first degree begins with 1 cm ^{2 of} area and progressively spreads in all directions. This description leads to inconsistency in the question of the total area affected by the surface area of the cartilage. II degree includes three different depths of chondropathy: surface and deep cracks and involvement of the subchondral bone in the process without specifying the size. Consequently, in this system there is no precise quantitative approach to assessing the degree of destruction of articular cartilage.

Characteristics of classification systems for arthroscopic evaluation of articular cartilage damage

Author	Description of the surface of the articular cartilage	Diameter	Localization
RE Outerb ridge, 1961	I - thickening and puffiness	I - description is missing	It begins most often on the medial surface of the patella; then "mirror" extends to the lateral surface of the intercondylar area of the condyles of the femur; upper edge of medial femoral condyle
	II - Fragmentation and Cracking	II - less than 0.5 inches
	III - Fragmentation and Cracking	III - more than 0.5 inches
	IV - cartilage and subchondral bone	IV - no description available
SW Cas sels, 1978	I - surface cartilage erosion	I-1 cm or less	Patella and the front surfaces of the femur
	II - deeper cartilage erosion	II -1-2 cm
	III - the cartilage is completely eroded, the subchondral bone is involved	III - 2-4 cm
	IV - articular cartilage completely destructured	IV - "wide area"
RP Float etal .. 1979	I - closed chondromalacia; simple thickening (simple bubbles) macroscopically, the surface is intact, varying degrees of expression from simple thickening to "deep edema", loss of elasticity	I - 1 cm, then the lesion spreads progressively in all directions	Lateral surface
	II - open chondromalacia: A) cracks - single or multiple, relatively shallow or extending to the subchondral bone B) ulceration - localized "loss" of the cartilage substance with the involvement of the subchondral bone. The surface of the bone may look "polished" (ebournection of the bone) Chondrosclerosis - the cartilage is inordinately compacted, incompressible	II - no description available	The medial surface (violation of joint ratios of 2 ° or more)
	Formation of "fragments" of cartilage - multiple, separated from each other by deep cracks extending to the subchondral bone Surface changes - cartilage breaking; longitudinal grooves, determined along the axis of motion of the joint	Not localized, however the entire contact area is involved	With the center on the crest separating the medial and distant surfaces
J. Beguin, B. Locker, 1983	I - softening, puffiness II - surface cracks III - deep cracks extending to the subchondral bone IV - involvement of the subchondral bone	No description	No description
JNInsall, 1984	I - swelling and softening of the cartilage (closed chondromalacia) II - deep cracks extending to the subchondral bone III - disassembly IV - erosive changes and involvement of the subchondral bone (osteoarthrosis)	No description	I-IV: the center of the patella crest with the extension equally to the medial and lateral surfaces of the patella IV: the opposite or "mirror" surfaces of the femur are also involved. The upper and lower third of the patella is usually slightly intact, the femur is slightly involved
G. Bently, J. Dowd, 1984	I - defibration or cracking	I - less than 0.5 cm	Most often at the junction of the medial and distant patellar surfaces
	II - cracking or cracking	II - 0.5-1 cm
	III - cracking or cracking	III -1-2 cm
	IV - defibration with or without subchondral bone involvement	IV - more than 2 cm

In the classification proposed by G. Bently, J. Dowd (1984), grades I, II and III have the same characteristics (cracking or cracking), and the differences between degrees are based on the diameter of the lesions. There is no mention of true chondromalacia. The degrees of IV correspond to two different depths of chondromalacia: dilatation with or without involvement of the subchondral bone, with a fixed size greater than 2 cm. A reasonable question arises as to what degree of lesions corresponds to the involvement of a subchondral bone with a diameter of less than 2 cm?

SW Cassels (1978) estimated the diameter of lesions in centimeters and the relative depth of lesions, initially believing that a smaller depth of lesions corresponds to a smaller diameter. In this case, what degree corresponds to superficial lesions involving the entire articular surface?

Thus, the above systems do not provide sufficient information on the depth, size and location of cartilage damage. In addition, the evaluation system should be applicable to both the knee joint as a whole and to each of its three divisions: patellofemoral, medial and lateral tiobiomoral. Nevertheless, without the quantitative mapping of the joint, the description of the localization of chondropathy outside this joint surface remains qualitative.

Modern classification systems

In 1989, FR Noyes, CL Stabler proposed their system of grading damage to articular cartilage. They divided the description of the articular surface (cartilage / subchondral bone), the depth of the lesion, the diameter and localization of the lesions. The authors distinguish three degrees of violation of the joint surface: 1st degree - the articular surface is intact; 2 nd degree - articular surface is broken, open lesion; 3rd degree - bone involvement. Each of these degrees is divided into types A or B depending on the depth of the lesion. Degree 1 implies chondromalacia. Type 1A corresponds to a moderate degree of softening of the articular cartilage; type 1B - significant softening with swelling of the joint surface. Degree 2 is characterized by any destruction of the joint surface without visualized bone involvement. Type 2A lesions include surface cracks (less than half the thickness of the cartilage); type 2B - more than half the thickness (deep cracks up to the bone). Degree 3 indicates the involvement of the bone. Type AO assumes that the normal bone contour is preserved; Type ZB - indicates cavitation or erosion of the bone surface. The diagram of the knee joint shows all the lesions detected, and the diameter of each of them is estimated by the researcher in millimeters using a special graded "hook". Depending on the diameter and depth of the lesion, a point scale is used to quantify the severity of chondropathy for each joint department and, ultimately, to conduct a joint joint account.

The system FR Noyes, CL Stabler was the first attempt of researchers to make a quantitative assessment of chondropathy, therefore it is not without drawbacks:

• All cartilage damage is represented on the diagrams of the knee joint in the form of a full circle with a diameter determined by means of a graduated "hook". This is not a sufficiently objective method of estimating the size, since most cartilage lesions do not have a strictly circular shape, often they are oval or have no definite shape. In addition, degenerative cartilage changes can often take the form of the deepest lesion in the center, surrounded by a zone of more superficial lesion of the cartilage; and this diameter can not be applied to this zone of "surrounding lesion" having a crown-shaped shape.
• Any lesion less than 10 mm in diameter is not considered as clinically significant, which leads to loss of sensitivity of the technique. When monitoring the action of the basic drug, any, even the smallest, lesions should be described.
• A point scale for assessing the depth and diameter of cartilage damage at the same time is arbitrary; it is not based neither on statistical methodology, nor on clinical evaluation and consideration of the severity of these injuries.

The newest of the proposed methods of arthroscopic evaluation of chondropathy are proposed by Kh. Aura1 and co-authors (1993, 1994), M. Dougados and co-authors (1994).

The first of these techniques is based on a subjective general assessment of chondropathy by the researcher; it is based on a 100-millimeter visual analogue scale (VAS), with "0" corresponding to the absence of chondropathy, and "100" - the most severe chondropathy. One VAS is used for each articular surface of the knee joint: the patella, the block (trochlea), the medial and lateral condyles, the medial and lateral plateau of the tibia. The VAS score is performed for each of the three sections of the knee joint and is obtained by averaging the VAS accounts for the two corresponding articular surfaces of the joint department.

The second technique is more objective and is based on the analytical approach, which includes an articular diagram of the knee joint with a gradation of the localization, depth and size of all available cartilage damage.

Localization

The procedure includes 6 detection zones: patella, block (intermiscus fossa), medial and lateral condyles (separately), medial and lateral plateau of the tibia (separately).

Depth

The system is based on the classification of chondropathy, proposed by the French arthroscopists J. Beguin, B. Locker (1983), it distinguishes 4 degrees of cartilage damage:

• Degree 0 - normal cartilage;
• Degree I - chondromalacia, including softening with edematous or without it; can correspond to degree 1, types A and B by FR Noyes, CL Stabler (1989);
• Degree II - in the cartilage there are surface cracks, single or multiple, giving the surface a "velvety" appearance; this degree also includes surface erosion. Cracks and erosions do not reach the surface of the subchondral bone. Can correspond to the degree of 2Apo FR Noyes, CL Stabler, 1989 (ie lesions occupying less than half the thickness of the cartilage);
• Degree III - there are deep cracks in the cartilaginous surface up to the subchondral bone, which are not directly visualized, but can be detected with an arthroscopic probe; degree III can be in the form of a "mouth of a shark" or a separate part of the cartilage, formed due to a single deep crack, "crab meat" due to multiple deep ruptures. Degree III also includes deep cartilage ulceration, which forms a crater, which remains covered with a thin layer of cartilage. Can correspond to degree 2B for FR Noyes, CL Stabler, 1989 (ie lesions that occupy more than half the thickness of the cartilage);

In osteoarthrosis of the knee joint, the destruction of articular cartilage often manifests itself in the form of a combination of different degrees of severity, when the heaviest affected areas are surrounded by zones of less pronounced lesions.

To create a unified chondropathy account, multivariate analysis using logistic multiple regression was used, in which the dependent value was the overall assessment of chondropathies by the researcher using VAS, and the independent - the depth and size of lesions. Thus, two systems for assessment of chondropathies have been created: the SFA-scoring system and the SFA-grading system.

SFA-account - a variable with values from "0" to "100", obtained for each department of the joint according to the formula:

SFA account = A + B + C + D,

Where A = size (%) of damage of the 1st degree x 0.14;

B = size (%) of damage of grade II x 0.34;

C = size (%) of damage of III degree x 0.65;

D = size (%) of damage of the fourth degree x 1.00.

Size (%) = median percentage of the medial condyle of the femur and medial plateau of the tibia (medial tibiofemoral department - TFO), lateral condyle of the femur and lateral plateau of the tibia (lateral TFO) or trochlea and patella (patellofemoral department - PFO).

The severity factors of chondropathies (0.14, 0.34, 0.65, 1.00) were obtained by parametric multivariate analysis.

SFA-degree is semiquantitative. The above values (size (%) of damages of I-IV degrees) are substituted into the formula to obtain the total degree (or category of severity of the chondropathy of the department) for each of the sections of the knee joint. The formula for each department is obtained by a nonparametric multivariate analysis using regression analysis; total - 6 categories for PFD (0-V) and 5 categories for medial and lateral TFO (0-IV). An example of calculating the SFA score and the SFA degree is presented in Table. 20.

[13], [14], [15], [16], [17],

ACR system

In 1995, the ACR committee proposed a system for calculating cartilage damage (Scoring system for cartilage). This system takes into account the depth, size and location of cartilage damage with subsequent insertion of data into the diagram of the knee joint. The depth of each damage is estimated by degree (classification of Noyes FR, Stabler CL, 1989); the size of each damage is in percent. A point scale is used to calculate the total score, the so-called damage score. The reliability of the latter was evaluated by D. Klashman and co-authors (1995) in a blind study: videotapes of 10 arthroscopic scans were examined twice by three arthroscopic rheumatologists, with high reliability as one expert in two studies (r = 0.90, 0.90; 0 , 80, p <0.01 for each), and between experts (r = 0.82, 0.80, 0.70, p <0.05 for each).

[18], [19], [20], [21]

Comparative analysis of reliability, significance and sensitivity to changes in arthroscopic systems SFA, VAS

X. Ayral and co-authors (1996) found a close correlation between arthroscopic quantitative assessment of chondropathy and an x-ray evaluation of the narrowing of the joint gap under weight loading conditions, namely the following:

1. general assessment of chondropathy (VAS) and narrowing of the radiographic joint gap (PC) of the medial joint, expressed in% (r = 0.664; p <0.0001);
2. SFA score and narrowing of the PC in the medial and lateral TFO, expressed in mm (r = -0.59, p <0.01 and r = -0.39, p <0.01, respectively);
3. SFA degree and narrowing of the PC in the medial and lateral TFO, expressed in mm (r = -0.48, p <0.01 and r = -0.31, p <0.01, respectively). Despite these results, arthroscopy was more sensitive than radiography: even deep and widespread cartilage erosion can remain undiagnosed on radiographs, even when carrying a weighted radiography. Of the 33 patients with osteoarthritis, which was ACR-rated, the narrowing of the PCR of the medial joint was less than 25% when loading radiography was performed, in 30 arthroscopy, chondropathy with an average VAS score of 21 mm (2-82 mm) was detected, with more 10 mm in 24 patients.

X. Ayral et al. (1996) found a statistically significant correlation (p <0.05) between damage to articular cartilage: 1) three parts of the knee joint (medial, lateral, PFO) and patient age; and 2) the medial joint and the body mass index. When repeated arthroscopy was performed after 1 year (41 patients), the same authors showed that changes in the severity of cartilage damage correlated with changes in functional deficiency of the musculoskeletal system (Lequesne index: r = 0.34, p = 0.03) and quality life (AIMS2: r = 0.35, p = 0.04). In the same study, the VAS score of the medial part of the joint changed from 45 ± 28 at the beginning of the study to 55 + 31 after 1 year (p = 0.0002), and the SFA score from 31 + 21 to 37 + 24 (p = 0 , 0003). Similar results attest to the high sensitivity of arthroscopy to dynamic changes in cartilage were also obtained by Y. Fujisawa and co-authors (1979), T. Raatikainen et al. (1990), and V. Listrat et al. (1997) in a dynamic arthroscopic assessment of changes in articular cartilage of patients with osteoarthritis under the influence of chondroprotective therapy (hyaluronan).

The use of microscopic technique allows arthroscopically visualize changes that are inaccessible to other methods of investigation.

Thus, arthroscopy, performed under local anesthesia, is an adequate method of instrumental diagnosis of osteoarthritis, and can also be used to control the effectiveness of treatment, primarily by modifying the course of the disease (DMOAD).

[22], [23], [24]