Patients with musculoskeletal pain cause major diagnostic problems for many physicians. There is sparse undergraduate teaching and variable and mostly limited post-graduate training. Consequently, these patients are often perceived as difficult to assess, and it may take a long time to take the full history and to perform a rewarding physical examination. In addition, treatment may be a challenge. At times, clinicians may even doubt whether their investment of time and resources in a clinical investigation of patients with musculoskeletal disorders really makes a difference.

This perception stands in contrast to the importance of these disorders in terms of their frequency and seriousness – not least in an occupational context. Worldwide, soft tissue and joint diseases including those of a degenerative character are prevalent, in particular in the aging population. Typically around 50% of the population report musculoskeletal pain at one or more sites. Back pain is the most common site of regional pain in younger and middle aged adults, and knee pain in older people. These disorders account for the largest proportion of lost “good” years in terms of experiencing functional limitations or suffering from pain in the limbs or the back. The work-related component of musculoskeletal pain has been increasingly recognized.

The widespread occurrence of musculoskeletal disorders in the maritime setting is no exception. Precisely the high prevalence and the major consequences for the work-ability of our seafaring patients in terms of pain and reduced functional level must commit us to provide the best possible prevention and management. In addition to high costs for the individual seafarer or fisherman in terms of livelihoods, musculoskeletal disorders have a major influence on the economy of the maritime industries.

This section does not intend to provide a comprehensive list of musculoskeletal diseases with description of their diagnosis, aetiology and management. It is rather the aim to extract specific issues relating to locomotor disorders that may be of particular importance to clinicians dealing with seafarers.

There is limited research on the epidemiology of musculoskeletal disorders in the maritime populations, and most studies that demonstrate the high frequency of musculoskeletal disorders in seafarers and fishermen are rather old.1,2 In spite of much less strenuous tasks in much contemporary seafaring and fishing, newer studies suggest that similar conditions still apply today.

In a study of the causes of morbidity among British merchant seamen, disorders in the musculoskeletal system accounted for the largest single reason for reporting sick (28%). Most were caused by trauma and the remaining were dominated by degenerative conditions such as osteoarthritis and low back pain.2 In a Japanese study of diseases in merchant vessels and fishing boats reported to the authorities, the proportion of musculoskeletal disorders (19.6%). was second to disorders of the digestive system. The occurrence differed clearly in between various types of trade ships and types of fishing boats.3 In a recent Norwegian study of the physical activity of seafarers, 51% had musculoskeletal pain with locations dominated by the low back, the shoulders and neck and the knees.4

Following injuries and poisoning, musculoskeletal disorders represented the dominant morbidity of workers on an American oil rig in the Mediterranean Sea5 and were the most frequent reasons for loss of health certificates compensation among Norwegian offshore workers.6

In a questionnaire study among Turkish fishermen 84% of respondents reported musculoskeletal symptoms, which constituted the largest group of health problems.7 A similar study by Törner of Swedish fishermen revealed 74% with musculoskeletal problems during the last 12 months. The significance of their complaints was indicated by reports of daily symptoms in 23%. Symptoms were more common among the 30-50 years old than among the younger or older fishermen and also more common among those that have been active in the profession for more than 21 years.8 In a subsequent study of musculoskeletal symptoms as well as signs, 87% of fishermen reported musculoskeletal symptoms during the previous year. 49% had complaints from the shoulders, 31% had health effects after previous hand-trauma, and 54% had low back symptoms. Many had a combination of several musculoskeletal disorders. Physical signs were more common among the elderly fishermen. 5% had Dupuytren’s contracture and 48% had chronic prepatellar bursitis. The agreement between symptoms and signs varied widely in between various parts of the body suggesting low validity of many of the applied physical tests.9 In a study from USA, low back symptoms were found to be the most common cause of fishermen’s work impairment followed by pain in the hands and shoulders.10

Increased hospital contacts for injuries and a number of musculoskeletal diseases among seamen (carpal tunnel syndrome for deck crew) and in particular fishermen (knee osteoarthritis, rotator cuff syndrome, carpal tunnel syndrome) have been found in a Danish register study.11 Raynaud’s syndrome was also increased.12 Previous accidents accounted for a major part of the morbidity. In the UK, trauma and orthopaedic conditions accounted to 30% of admissions and 37% of outpatients in a hospital that dealt with seafarers, and this number was more than double than that for general English hospitals.13 The same study demonstrated that the most common reason for failing the medical examination was joint diseases and joint replacements.13 Upper limb disorders were reported in 5.2% of Lithuanian seafarers.14

The reports on musculoskeletal health do not necessarily reflect ongoing exposures. Heavy tasks on board in the younger days of sailing may well have influenced the current locomotor health of elderly crewmembers. E.g. shovelling ice and cleaning fish onboard is now overtaken by machinery in many fishing vessels. Due to the less strenuous character of much of the work on board many older crews can still fulfil their duties and maintain their employment. Still, however, at times much work remains heavy and awkward, e.g. in the engine room, and the work on board is generally managed by fewer crews today than previously. In addition, much monotonous and highly repetitive work has not disappeared. Examples include cleaning and maintenance work such as removal of rust and painting, which form risk exposures that should be limited in extension. It should also not be forgotten that much of the most arduous and dangerous work on board is often outsourced to gangs of contractors in low-income countries who come onboard in one port and disembark elsewhere when the work is done.

The embarkation of seafarers with severe locomotor conditions may be declined for health reasons, or seafarers with limitations may be restricted with regard to the duration of the employment time or to the type of services. The statutory medical certification of seafarers assesses in particular diseases that impose serious functional limitations relating to work and especially to emergency situations. Examples may be grave cases of, e.g. inflammatory joint disorders such as rheumatoid arthritis, severe osteoarthritis of hip or knee, or vertebral degeneration or disc herniation causing root compression. Some countries, manning agencies or shipowners may go further than that by demanding the complete absence of any such condition of even minor severity and also of other mild musculoskeletal ailments, thereby preventing the employment at sea of a major part of seafarers, in particular the elderly ones. In the UK, a recent study showed that the most common reason for failing the medical examination was joint disease and joint replacement.13

Still, in a practical context, many seafarers and fishermen in active occupation do suffer from musculoskeletal ailments as consequences of previous accidents or from age-related degenerative conditions that may restrict them from certain functions on board.

Some of these conditions may be work-related, i.e. actually caused by a risk factor on board, examples being chronic low back problems after shovelling ice in a fishing vessel for an extended period of time or upper limb pain consequent to painting on board. Disorders such as lower limb osteoarthritis may also be associated with physical exposure from heavy work, squatting, kneeling or just residing on a moving deck, in addition to the relation to conditions such as obesity that are prevalent in the maritime population.15 Work-exposures and other factors in the maritime setting may also cause further progression of a disorder with may or may not be caused by work or at least lead to pain-aggravation during certain work tasks