Symptoms of osteoporosis in osteoarthritis

Systemic osteoporosis is a complex multifactorial disease, usually characterized by slow asymptomatic progression until the occurrence of bone fractures, which in most cases are the first reliable signs of osteoporosis, and the occurrence of spontaneous non-traumatic fractures or fractures that are inadequate to the severity of the injury is typical.

In one of the studies, a comparative assessment of the bone tissue condition in patients with osteoarthrosis, rheumatoid arthritis and practically healthy individuals was carried out. 348 patients with RA were examined: 149 patients with a diagnosis of osteoarthrosis established in accordance with the criteria proposed by the ACR (1994), and 199 patients with a reliable diagnosis of rheumatoid arthritis according to the ARA criteria. The patients were examined clinically, including determination of the body mass index (BMI), and using instrumental methods. OFA was performed in 310 patients; some patients (n = 38) were examined by ultrasound densitometry (USD) of the calcaneus (ultrasound densitometer Achilles, «LUNAR»). All patients underwent radiography of the spine with subsequent calculation of morphometric indices of radiographs - the central index of Barnett, Nordin for assessing the condition of bone tissue. A correlation analysis was performed (r<0.35 was considered a weak relationship).

The main symptoms accompanying generalized bone tissue rarefaction in RZS include anatomical changes and pain syndrome.

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Anatomical changes

Anatomical changes in the form of decreased height (on average by 4.8+0.31 cm) during the disease were noted by 46 examined patients, or 23.11% of their total number, and postural disorders were registered in 76% of patients. The decrease in height was determined by measuring the distances head-symphysis (1) and symphysis-feet (2): a decrease in the ratio (1) to (2) by more than 5 cm indicated osteoporosis. When conducting a correlation analysis, a very weak correlation was found between anatomical changes and the severity of osteoporosis (r=0.09).

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Pain

Pain syndrome caused by pathological processes in bone tissue, accompanied by its rarefaction, was noted in 72% of patients in whom densitometric examination revealed violations of the bone mineral density.

Pain syndrome included:

1. Localized pain, which we divided into “periosteal”, characterized by an acute onset and fairly clear localization, “pseudoradicular” (like lumbago), poorly differentiated and tending to become chronic, with muscle rigidity (muscle spasm) as a reflex reaction to pain and, as a rule, with the absence of compression pain, and “radicular” - both acute and chronic.
2. Generalized pain in the spine, reaching its greatest intensity mainly in its “transitional” zones (cervicothoracic, lumbothoracic, lumbosacral).

The clinical variants of the course of osteoporosis of the vertebrae were as follows:

• an acute pain syndrome, usually associated with a fresh compression fracture of a vertebra or several vertebrae, characterized by acute intense pain in the affected part of the spine, followed by acute reactive muscle tension in the affected area, often in the form of a girdle-like, radiating pseudoradicular pain in the chest, abdomen, or femur;
• chronic: complaints of dull back pain over a long period of time, constant or periodically occurring, accompanied by the above-described anatomical changes - decreased height, deformation of the spine (slouching was observed in 60% of all examined patients). Symptoms in such patients slowly increased with an increase in the duration of the disease, and were characterized by alternating periods of exacerbation with remissions, when the pain syndrome became less pronounced or was practically absent. It is assumed that the cause of such a course of osteoporosis is creeping deformation of the vertebral bodies (multiple microfractures of trabeculae) with a progressive decrease in the height of the vertebrae, deformation of the spine - an increase in kyphosis of the thoracic region.

3. Pain in various bones of the skeleton (ossalgia). It was previously believed that since there are no pain receptors in the bone, the pain syndrome in osteoporosis cannot occur without deformation of the vertebral body, however, this assumption has now been refuted. Thus, diffuse bone pain, sensitivity to tapping of the ribs and pelvic bones, and general sensitivity to concussion were noted in patients provided that rarefaction of the trabecular structure of the CT scan was recorded on radiographs and there was no deformation of the vertebral bodies. Such pain can be caused by bone microfractures or irritation of the periosteum by a protruding porous bone. The existence of a dependence of pain intensity on the severity of osteoporosis in patients with RZS has been confirmed by other researchers. The strongest positive correlation was noted between generalized pain in the spine and osteopenic syndrome (r = 0.62).

Thus, anatomical changes in the spine and pain syndrome (localized pain, generalized pain in the spine, ossalgia) are the main clinical manifestations accompanying generalized rarefaction of bone tissue in RZS. Identification of the corresponding clinical signs at an early (before fractures) stage of osteopenia development in this category of patients will allow the practitioner to purposefully conduct differential diagnostics of such disorders and promptly prescribe adequate therapy taking into account the risk factors for the development of spontaneous (pathological) fractures - the age of patients (especially in women in the early postmenopausal period), systemic manifestations, as well as specific therapy (systemic administration of GCS, etc.).

We emphasize that establishing a diagnosis of osteoporosis based solely on clinical and anamnestic data is not possible and requires confirmation using laboratory and instrumental research methods.

Novocaine, trimecaine blockades, and non-narcotic analgesics have proven themselves well in symptomatic therapy of pain syndrome in osteoporosis. Tramadol is especially effective in patients with rheumatological profile, allowing to significantly reduce the severity (or eliminate completely) of pain syndrome caused by both osteoporosis and joint damage (arthritis, arthralgia).

Pathological fractures

It is known that the clinical stage of osteoporosis development is characterized by pathological (spontaneous, brittle, osteoporotic) fractures that occur in the absence of a traumatic factor or when the severity of the injury does not correspond. The data available in modern literature indicate a close correlation between the predisposition to fractures and osteoporosis.

The parameters that influence the condition of bone tissue and, accordingly, the frequency of osteoporotic fractures include: mass or BMD (bone mineral density, g/cm2 ⁾, tendency to loss of balance, bone geometry (especially the femoral neck), bone “quality”, and microarchitecture of the bone tissue.

Most researchers attach particular importance to the occurrence of fractures before the age of 65 years to BMD, which, regardless of other factors, closely correlates with bone strength and the risk of fractures. A decrease in BMD in any part of the skeleton by 1 SD from the norm leads to a 1.5-fold increase in the risk of fractures.

Prospective and retrospective studies have established a direct correlation between a history of fractures and/or an increased risk of fracture and low bone mass. SR Cummings et al. (1993) showed that women with a femoral neck BMD of (< -2 SD) had an 8.5-fold higher risk of hip fracture than those with a BMD of >2 SD. Each SD decrease in femoral neck BMD increased the risk of fracture by 2.6 times, indicating a significant relationship between BMD and the likelihood of fracture.

In the group of patients with RZS examined by us, fractures in the anamnesis were noted in 69 (19.8%) people. The greatest number of fractures occurred at the age of 52 - 56 years for women and about 60 years for men. It should be noted that in 76.7% of cases, fractures occurred as a result of only minimal load, i.e. there was a discrepancy between the severity of the injury and the strength of the provoking moment.

Despite the fact that in osteoporosis all parts of the skeleton have increased fragility, some of them are typical sites of osteoporotic fractures, namely the bodies of the lower thoracic and upper lumbar vertebrae (the so-called transitional zones of the spine), the proximal end of the femur (subcapitate, intertrochanteric, subtrochanteric parts), the proximal end of the humerus and the distal part of the radius (Colles fracture).

Fractures of the long tubular bones, most common in the femur, occur approximately 15 years later than compression fractures of the vertebrae; the average age of a patient with a wrist fracture is 65 years, and with a femur fracture - 80. This is probably due to the fact that the femur, including its neck, contains a greater amount of compact bone than the body of the vertebra.

The presence of compression fractures of the vertebral bodies (including wedge-shaped deformation and lens-shaped vertebral bodies with a decrease in their height) was confirmed by data from the central Barnett-Nordin index.

In the group of patients with fractures, the BMI was 17.15-33 conventional units (on average - 24.91±4.36 conventional units) and did not differ significantly from the BMI in the main group as a whole (p>0.1). We assume that general trophic disorders in themselves do not serve as an important prognostic factor for pathological fractures.

Although a decrease in BMD is a leading factor determining the risk of osteoporotic fractures, according to clinical and epidemiological studies, the risk of skeletal fractures does not always correlate with a decrease in BMD according to densitometry data, i.e. what is meant is not “quantitative” but “qualitative” changes in bone tissue.

This is well illustrated by the currently available contradictory data obtained by different researchers. Thus, S. Boone et al. (1996) found in population studies that patients with osteoarthrosis (and even their blood relatives) have a reduced risk of skeletal bone fractures (OR -0.33-0.64), especially of the femoral neck. At the same time, the results of prospective studies indicate that patients with osteoarthrosis, despite an increase in BMD, do not have a reduced risk of "non-vertebral" fractures compared to patients without osteoarthrosis. Moreover, patients with coxarthrosis have a 2-fold increase in the risk of femoral fractures. These data are extremely important, since they indicate the need for measures to prevent osteoporotic fractures of the skeletal bones not only in patients with osteoarthrosis with reduced, but also "normal" and even "increased" BMD. It should also be taken into account that the "high" BMD according to densitometry data is often an artifact caused by degenerative changes in elderly people (osteophytes, scoliosis, etc.). Finally, in patients with osteoarthritis, as in rheumatoid arthritis, the development of periarticular osteoporosis of the bones adjacent to the affected joint was detected. It is believed that the tendency to osteoporotic fractures in osteoarthritis, despite the absence of a pronounced decrease in BMD, is associated with a violation of the "quality" of bone tissue and a violation of muscle mass, creating the prerequisites for accidental loss of balance.

Separately, it is necessary to mention the destruction of bone tissue in the sections that are "targets" for aseptic (avascular) necrosis - the death of a bone section due to insufficient nutrition or its complete cessation with the preserved vital activity of adjacent bone zones, primarily the heads of the femurs. We observed this complication in 7 (3.52%) patients with rheumatoid arthritis and in 2 (1.34%) with osteoarthrosis. The death of bone cells with the preservation of the interstitial substance is a characteristic feature of this process (the mineral composition of the dead bone does not change). The dead bone section loses liquid elements of blood, lymph and tissue fluid, as a result of which there are more inorganic substances per unit of mass of dead bone than per unit of mass of living bone. In the surrounding living bone tissue, vascularization and bone resorption increase, therefore, on the radiograph, the osteonecrosis area appears more intense than the surrounding bone tissue.

It can be assumed that avascular necrosis represents an extreme degree of bone tissue rarefaction with the loss of both its mineral and organic components.

The effect of osteoarthritis disease duration on bone mineral density

The dependence of BMD on the duration of the disease is a poorly studied issue. The lowest densitometric indices were recorded in patients with osteoarthrosis for 6-10 years. In the group of patients with osteoarthrosis duration of 1-5 years and more than 10 years, the bone mass is somewhat higher, although in the group as a whole it does not reach the indices of persons of the same age without musculoskeletal system damage, as well as persons who have been ill for less than a year. A tendency towards an increase in BMD was also found in patients with osteoarthrosis who have been ill for more than 10 years. In our opinion, this is explained by the development of compensatory processes in bone tissue, reducing its metabolism and slowing down the rate of loss of the mineral component by the skeleton.

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Features of the development of osteoporosis in patients with osteoarthritis

According to clinical studies, it has been established that the BMD of the spine and femoral neck, as well as body weight, are higher in patients with osteoarthritis of the hip joint compared to patients with predominant damage to the small joints of the hands and individuals in the control group (without pathology of the musculoskeletal system).

Individuals with multiple joint lesions (polyosteoarthrosis) had significantly lower BMD. The BMD-Z index in patients with polyosteoarthrosis and oligo(mono)osteoarthrosis was (-1.39+0.22) and (-0.15+0.29) (p<0.01) in the spongy bone tissue, and (-1.13+0.47) and (+0.12+0.52) in the compact bone tissue, respectively. It should be noted that in 69 (76.7%) patients with mono- or oligoarthrosis, the BMD was significantly higher than the age norm. Probably, in this case, the degenerative-dystrophic process caused by osteoarthrosis had a protective effect on bone loss.

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