Determining Work-Relatedness of Acute Shoulder Trauma. Review 2017

Abstract

The chronicity of rotator cuff tears and their cause with increasing age has been extensively studied resulting in widely varying prevalence estimates. Focusing on a reported prevalence rate that increases with age to as high as 80% for 70 year olds can result in denial of reimbursement for work-related rotator cuff tears based on the presumed existence of underlying tendon pathology. The age at which inherent degeneration of the rotator cuff becomes a consideration in worker's comp judgments is vague at best. There are instances of acute shoulder trauma that occur in individuals as young as 20 years and even younger in athletes before significant tendon degeneration occurs. Multiple studies report low prevalence rates of asymptomatic rotator cuff tears in individuals less than 50 years. Acute shoulder trauma occurring at work in young workers provides strong evidence that the exposure event underlies any resulting shoulder disorder rather than tendon degeneration and as such is compensable. It can be questioned whether work-related acute shoulder trauma occurring at any age should be attributed to inherent tendon degeneration. IntroductionRotator cuff disease is the most common upper extremity disability [1]. Tendons are connective tissues primarily made up of aligned type I collagen fibrils. The primary cells in tendons are fibroblasts which produce the extra cellular matrix components. As a tendon ages, there is a drop in both cell numbers and cell synthetic activity which could affect mechanical function as tendon structure and composition are altered. These changes likely underlie the increase in tendon injuries with aging [2]. The principal focus of this review is the determination between acute traumatic and chronic degenerative rotator cuff tears (RCTs) which has huge implications for compensation of workrelated injuries. Determining the underlying cause of an RCT is complicated by an increasing incidence of asymptomatic rotator cuff disease with increasing age due to ongoing degeneration of the shoulder tendons. As the age of patient's increases and along with possible RC degeneration, it becomes increasingly difficult to exclusively attribute shoulder injuries to work-related trauma. However, ethically and given the original intent of worker compensation legislation, work-related trauma to the shoulder should be compensable [3].Determining the chronicity of tendon tears remains an issue that is still being pursued. Codman in 1931 stated four prescient hypotheses for RC supraspinatus tendon lesions: (1) trauma, (2) calcification, (3) necrosis or osteoarthritis, or (4) direct result of attrition [4]. Extrinsic and intrinsic factors are recognized to affect rotator cuff tears. Neer identified extrinsic factors based on impingement of the cuff against the coracoacromial arch when the arm is elevated in a forward direction leading to tendonitis and tears [5]. Variable morphology of the acromion includes spurs [6][7][8] and a hook-shaped acromion [9,10] that influence the degree of impingement and li...