Introduction. Timely and adequate diagnosis and treatment of degenerative-dystrophic diseases of the bone and joint apparatus, which include epicondylitis (epicondylosis), including professionally caused, continues to be a serious health problem today, since they cause significant economic damage associated with temporary and persistent disability of the active part of the world’s population. In this regard, the search for methods and methodological approaches to improve the radiation diagnosis of this disease remains relevant. The study is devoted to solution of important medical problems, including occupational diseases-optimization of X-ray of the ulnar epicondylitis based on the use of new methodological approaches quantifying the density of pathological remodeling of bone structures in the subject area, that allow to objectify the direction of changes in monitoring intensity changes in the estimated structures.The aim of the study is to improve the quality of x-ray diagnostics of ulnar epicondylitis based on a precision assessment of the optical density of bone and periarticular tissues using digital radiography.Materials and methods. A comparative analysis of the results of a comprehensive clinical and radiological examination of patients, workers of the main group (fitters and laborers machine-building plants) working age range of 30–50 years with a clinical picture of subacute phase of the ulnar epicondylitis in the absence of a pathognomonic ultrasound findings and x-ray morphological signs of the disease. X-ray studies were performed using digital low-dose x-ray diagnostic devices. Visualization, processing, analysis of medical images and comparison of results in the dynamics of research were carried out using the programs «Lins machaon doctor’s workstation». To measure the conditional optical density of bone and soft tissues, we used the ROI tool (zone of interest), which allows us to determine the desired value in areas of different dimensions. Measurements were performed on digital radiographs and computer monitor screens in the areas of interest: the lateral parts of the humerus condyles and adjacent periarticular tissues with the calculation of the average values of the optical density index (ID) and optical density gradients (IDG) relative to the density of periarticular soft tissues.Results. Analysis of the results of a posteriori osteodensitometry of the distal humerus within the framework of the developed algorithm, which includes the use of absolute and relative indicators of conditional optical density after preliminary color correction of digital x-ray images of bone and paraossal tissue structures, allowed us to expand our understanding of the topography of the distribution of mineral saturation in the condyles of at-risk individuals relative to those of the control group. It was found that the indicators of optical density of bone and paraossal tissues can be a kind of (conditional), sometimes the only indicators of the degree of severity of changes, positive or negative dynamics of pathophysiological processes. Density differences in the distal parts of the right and left humerus (bony and soft -tissue paraossal structures of the condyles) in the control group (conditional norm) in terms of absolute optical density and its gradient, regardless of the assessment area, were insignificant (statistically unreliable), although they were multidirectional. In patients with clinical signs of epicondylitis in the absence of x-ray morphologically detectable structural changes, a decrease in ID and the dynamics of its recovery at various stages of observation were revealed. Even when the ID of the actual bone structure is relatively equal, the IDG differs in different people, since it is largely determined by metabolic processes that are dynamically more labile than in the bones, and thus serve as a kind of indicator of their intensity. Taking into account the relative torpidity of perestroika processes in the structures of the bone tissue of the condyles in epicondylitis, IDG should be considered a more informative indicator of their dynamics. The importance of optical density indicators as predictors of the considered pathology is particularly evident in the process of analyzing the results of its diagnosis and development in the dynamics of observations not so much at the collective as at the individual level of assessment.Conclusions. The application of the developed methodological approach allows us to significantly expand our understanding of the topographical distribution of the density of bone and soft tissue structures of the distal humerus at various stages of examination of patients, including the early subclinical phases of possible pathology, even in the absence of visually detectable x-ray morphological changes. The use of an original algorithm for evaluating tissue density will reduce the negative role of the so-called «human factor» and thus significantly ensure the objectivity of the interpretation of research results.Funding. The study had no funding.Conflict of interests. The authors declare no conflict of interests.

The relevance of the study is due to the high prevalence of degenerative-dystrophic changes in the bone-articular apparatus and periarticular tissues in the structure of diseases in General in the population and in persons working in contact with harmful production factors. The most common in clinical practice diseases of the shoulder girdle with lesions of bone-cartilage and tendon-muscle structures include arthrosis and changes in periarticular tissues, including: periarthritis, tendinitis, tenosynovitis (tendovagines, entezity), enthesopathy, bursitis, ruptures of the rotator cuff of the humerus, the symptom of “collision” — impingement sholder syndrome, lesions of the acromioclavicular and clavicular joints. Treatment of these conditions is not a solved medical and social problem, so perhaps their early diagnosis today is still relevant in the sense of primary prevention of disability of the population, including the working part of it-improving the quality of diagnosis of shoulder joint pathology today can be achieved through the use of new methodological techniques, objectifying the degree of severity of x-ray morphological changes on the basis of appropriate quantitative characteristics.The aim of the study was to optimize the diagnosis of osteopenia (osteoporosis) using digital reference osteodensitometry to objectively assess the effectiveness of therapy for ostearthritis and periarthritis of the shoulder joint.A comparative analysis of the results of clinical and radiological examination of the condition of the shoulder joint engineering plants workers with the presence of the clinic osteoarthritis and periarthritis shoulder joint and assessment of mineral status of humerus at primary diagnosis and in the dynamics of observations on the basis of use of new technologies for digital osteodensitometry.The use of reference digital osteodensitometry made it possible to objectively assess the levels and topography of mineral distribution in the proximal humerus in the control group and in patients with osteopathy at various stages of clinical observation.The mineral density of the proximal humerus has differences depending on the sector and zone of study, being an objective criterion for the orientation of the restructuring of their structure and, consequently, the effectiveness of therapeutic measures.Digital reference osteodensitometry, as the most affordable method of early detection of osteoporosis or osteopennia, can be used in complex clinical and radiological examination of patients with suspected or already professionally caused osteopathy of the shoulder joint.