Results

There were small difference in prevalence between the right and left sides, and between males and females, but these were not statistically significant (that is, the 95%CI did not overlap (p > 0.05)). Nor were there statistically significant differences between skeletons from the three archaeological sites, which were then considered together in further analyses. The distribution of OA in the upper CV joints for all skeletons is shown in Figure 1. The only significant difference in prevalence was in the age categories – young adults versus old adults – where, as expected, the old adults had a higher prevalence of OA (Figures 2 and 3). However, it was notable that both age categories had the same distribution of OA of the CV joints, with pronounced peaks at the levels of the first, eleventh and twelfth ribs (see Figures 2 and 3). Generally the superior CV joints had a higher prevalence than the lower, while for the CT joints the highest prevalence was found for the four lowest joints (the seventh to the tenth).

Figure 1

Figure 1

Prevalence of OA in superior CV joints for all skeletons combined.

Figure 2

Figure 2

Prevalence of OA in CV joints in young adults.

Figure 3

Figure 3

Prevalence of OA in CV joints in older adults.

Discussion

Results were compared to those of two other studies, one by Nathan and his colleagues who examined 346 skeletons from the Hamann-Todd collection (Nathan et al. 1964) and Bevan’s study of 113 skeletons from Medieval and post-Medieval London (Bevan 2007). The Hamann-Todd collection contains approximately 3,000 skeletons that were collected between 1893 and 1938 and is now housed in the Cleveland Museum of Natural History. Nathan and his colleagues found that approximately 48% of the skeletons in their sample had OA in at least one CV joint and that there were peaks in prevalence at the first, eleventh and twelfth ribs, as was found in the Nubian material. Bevan also found that the distribution of OA within the spine in her material from Medieval and post-Medieval London was the same for both time periods, with peaks also at the level of the first, eleventh and twelfth ribs. Nathan and his colleagues did not examine the CT joints but in Bevan’s study, the distribution was essentially the same as in the current study, with the highest prevalence in the four lowest levels.

The results from these three studies of material widely separated in time and space, and representing individuals whose ways of life must have differed considerably from each other, strongly suggest that external factors such as environment and occupation or other activities must have contributed much less to the causation of their OA (at these joints, at least) than internal factors such as the structure, and movement of the joints. Osteoarthritis is a chronic disease with a multifactorial aetiology that may affect different joints in different ways (Arden & Nevitt 2006). Recent clinical research suggests there may be a strong genetic component to the development of OA (Garner, Alshameeri & Khanduja 2013), and these genetic risk factors also seem to be specific to different joint sites (Reynard & Loughlin 2013).

Mechanical factors such as repetitive joint loading also increase the risk of OA in a joint (Arden & Nevitt 2006). While the CV and CT joints do not experience joint loading stress in the same way as the weight-bearing joints such as the knee or hip, they do experience biomechanical stress from the constant movement caused by respiration. This, along with chemical mechanisms affecting the articular cartilage metabolism, could influence the presence of OA in non weight-bearing joints such as the CV and CT joints (Garner, Alshameeri & Khanduja 2013).

While genetic and environmental factors likely played a role in the development of OA in the skeletons examined, the remarkable similarity in the pattern of CV and CT joint OA across temporal and geographic regions suggests that biomechanical stress is a particularly strong aetiological factor in the development of OA in these particular joints.

Discussion

The features of osteomyelitis in late Victorian and early Edwardian Britain are similar in many respects to those of the present-day disease, in Westernised countries at least. Thus, in contemporary society it remains a disease predominantly of the young, with the femur and the tibia being most commonly affected (Goergens et al. 2005) as was also the case in the late 1920s (Hughes 1927). It was then, and is now a relatively uncommon disease with an incidence reported in a modern study from the Royal Hospital for Sick Children in Glasgow (the successor to GCH) as being 2.9 per hundred thousand (Blyth et al. 2001). Unfortunately it is not possible to calculate either the incidence or the prevalence of the disease in the population from the historic admission records as the denominators necessary for these calculations are not known. Nevertheless, it seems reasonable to suppose that the disease was more common in the past than it is now. At GOSH the disease accounted for about 0.15% of all admissions in the five years beginning 1890 but was 0.76% after 1900, an increase that was significant at p = 0.05 Contemporary proportions are generally substantially lower than this although whether the disease is increasing or decreasing in prevalence nowadays is not clear. An Australian study found that the proportion of cases of osteomyelitis admitted between 1968 and 1972 was 0.17%, and 0.12% between 1998 and 2002; this difference was not statistically significant (Blyth et al. 2001). An earlier study from Australia, by contrast, showed that the frequency rose after 1951, which has been suggested to be due to the infectious organism (presumably S. aureus) becoming resistant to penicillin (Gilmour 1962); it is hard to see how resistance to antibiotics would have affected the numbers presenting with the disease, however, although it may have affected the outcome. More recent data from the USA have shown an increase in frequency, rising from 0.26% to 0.60% of all admissions over a four year period, an increase that was considered to be due the emergence of methicillin resistant strains of S. aureus (Arnold et al. 2006). Again it is difficult to follow this argument since the knowledge that the infectious organism was resistant to treatment would follow only after treatment had begun.

It is not certain what organisms were responsible for the development of osteomyelitis in the children represented in the historic hospital records, but it was during this period that Bommers (1893) first isolated S. aureus from the blood of a patient who had died from the disease. There is little reason to suppose that this was in any way unusual, and so it is likely that S aureus was the most common infectious agent then as now.

The most notable differences between the historic and present-day nature of the disease relate to cure rates, case fatality rates, and length of stay in hospital. In the historic period no more than a third of all patient were said to have been cured by surgery to drain the abscess and to remove sequestra, then the only forms of treatment (Klenerman 2012: 42–3). Death rates were high and about a fifth of all children admitted could expect to die; at GCH the death rate for boys (36%) was exactly the same as for children admitted to the same hospital with osteomyelitis between 1936 and 1940 (White & Dennison 1952). With the advent of effective antibiotics (notwithstanding the emergence of some resistant strains), death rates are now so low as to go unreported.

The length of stay in hospital has also declined considerably in recent times. One study (Blyth et al. 2001) reports a median length of stay of 15.7 days compared with a median stay of 28.5 days for the historic cohort, with eleven of the children having stays in excess of 100 days. In the later study from GCH, White and Dennison (1952) also found that a number of children had excessively long stays, the record being one patient who remained in hospital for almost 500 days. The authors noted that there were many factors affecting the duration of stay, of which home conditions were often the most influential; this is, arguably, equally likely to have been the case in the earlier period.

In many measures, the epidemiology of osteomyelitis has changed relatively little over the past one hundred and fifty years, which suggests that internal factors have probably also changed little in importance when considering the aetiology of the disease. External factors, on the other hand, may account for the probable decrease in the frequency of the disease. That external factors may be important in the natural history of osteomyelitis, as is shown by a study from Uganda which demonstrated that there patients tended to be much older at diagnosis, and also that the bones most commonly affected were the phalanges of the hand because infection most often followed pricks to the fingers (Ibingira 2003).

In the historic period, the most important external factors were almost certainly the state of nutrition and the lack of cleanliness which gave rise to a high prevalence of skin infections. Nutritional status is important for the maintenance of an effective immune system, and malnutrition is the most common cause of immunodeficiency worldwide (Chandra 1997). During a Victorian childhood, nutritional status was likely to have been considerably worse than today. Victorian working class boys, for example, only approached the first one-tenth of the first percentile of height compared with their modern counterparts. Working class girls fared little better, their height falling short of the first percentile on modern growth charts (Horrell, Meredith & Oxley. 2009). Skin infections, particularly boils and carbuncles were rife during the Victorian period, at times being reported as achieving epidemic proportions (Hunt 1852). Nowadays, few have seen a boil, much less had one. Thus, if there has been a reduction in the incidence and prevalence of osteomyelitis since Victorian times, it seems most probable that it is due in large measure to external factors such as improved standards of nutrition and hygiene.