Musculoskeletal disorders in Swedish military aircrew : screening and clinical examination of the cervico-thoracic region

Abstract: Musculoskeletal disorders (MSD) are a common and growing occupational problem in military aircrew. Intervention studies attempting to reduce such issues have only showed limited preventive effects. Furthermore, in-depth knowledge of the clinical presentation of aircrew members with painful episodes is lacking. This thesis was conducted to add evidence to the ongoing work of the Swedish Armed Forces (SAF) for the prevention of MSD. The overall aim of this thesis was to estimate the occurrence of MSD in general and specifically cervico-thoracic pain and its associated factors among SAF aircrew and to evaluate clinically relevant tests, prior to the adaptation of a musculoskeletal screening protocol (MSP) for use in the SAF medical health care system. All participants included in the four studies of this thesis were employed in the SAF. Two cross-sectional studies (Study I; n=351, Study III; n=73) aimed to establish the occurrence of MSD in aircrew compared with army deployed soldiers (Study I) and between fighter pilots, helicopter pilots and rear crew (Study I), as well as identify associated factors of cervical, thoracic and shoulder region pain (Study I) and cervico-thoracic pain (Study III). Study II had a test-retest design and aimed to examine inter-rater (n=37) and test-retest (n=45) reliability of movement control tests. In study III, test performance was compared between fighter pilots, helicopter pilots and rear crew. Study IV had a cross-sectional (n=18) and a prospective observational cohort (n=47) design and aimed to explore physical symptoms and functional limitations in aircrew with cervico-thoracic pain, establish 12-month cumulative incidence and to identify risk factors for cervico-thoracic pain.The main findings of this thesis were that when compared to deployed soldiers, military aircrew reported higher prevalence of MSD in the cervical, thoracic, shoulder, and lumbar regions (80% reported at least one painful area during the previous year). Working as aircrew, and a lower rating of one’s physical health, were significantly associated with pain in the cervical, thoracic and shoulder regions (Study I). Two physical therapists could reliably rate movement patterns for the majority of movement control tests in the affected areas. Lower reliability was however seen for test-retest conditions (Study II). Movement control and measures of cervical range of motion (ROM), but not cervical strength and endurance, were associated with cervico-thoracic pain among military aircrew. Specifically, less control of both neck and lumbar flexion movements, and lesser cervical flexion ROM were associated with cervico-thoracic pain. Differences were found between fighter pilots, helicopter pilots and rear crew for lumbar flexion movement control and cervical lateral flexion ROM (Study III). Physical symptoms and functional impairments of aircrew with high (pain) intensity, flight-elicited and work-affecting cervico-thoracic pain showed an individual presentation. Previous pain episodes, lesser cervical flexion ROM, and lesser cervical flexor muscle endurance were identified as risk factors for future cervico-thoracic pain, which had a 12-month cumulative incidence of 23% (Study IV).Findings from this thesis strongly indicate that MSD in SAF aircrew is an occupational problem that need to be solved. The cervico-thoracic region was especially common in SAF aircrew. Movement control can reliably be assessed, but with less stability for repeated measures. While pain history and physical performance can to some degree be used to identify aircrew at risk for further cervico-thoracic pain, the clinical presentation of their physical symptoms showed individual presentation. The effects of implementing the MSP in the SAF as a primary and secondary preventive intervention, as well as rehabilitative strategies, need be systematically evaluated.