Morphological Characteristics of Healthy and Osteoarthritic Joint Surfaces in Archaeological Skeletons K. A. PLOMP, a,b * C. A. ROBERTS b AND U. STRAND VIÐARSDΌTTIR a a Evolutionary Anthropology Research Group, Department of Anthropology, Durham University, Durham, England b Department of Archaeology, Durham University, Durham, England ABSTRACT Osteoarthritis is a major health concern in living populations, as well as being one of the most common pathological lesions identified in the archaeological record. The aetiology of the disease remains unclear, with a multi-factorial influence of physical strain, age, genetics, and obesity. Previous studies have identified a relationship between the presence of knee osteoarthritis on the distal femoral joint and the morphology of the intercondylar notch, patellar groove, and medial condyle. The current study expands this research to investigate the relationship between distal femoral, distal humeral, and proximal ulnar joint morphology and osteoarthritis with 3D shape analysis techniques. These methods provide a more detailed analysis of joint morphology in order to determine any relationship between 3D shape and osteoarthritis. The results indicate a complex relationship between joint shape and knee osteoarthritis, with eburnated right femora showing a statistically significant association. The shapes associated with eburnated or affected femoral joints can be explained by osteophyte development, and therefore likely represent systematic shape changes and not a particular joint shape predisposing individuals to the condition. There was no identifiable relationship found in the proximal ulna or distal humerus, indicating that joint shape is unlikely to influence the development of the condition in the elbow joint and that any shape changes produced by osteoarthritis are not systematic or quantifiable. The joints analysed in this study were highly influenced by asymmetry, sexual dimorphism, and allometry, resulting in a small sample size of affected joints in many datasets. Further analyses of large skeletal samples are needed to more thoroughly investigate the possible relationship of distal femoral joint shape and osteoarthritis. Copyright © 2013 John Wiley & Sons, Ltd. Key words: eburnation; geometric morphometrics; osteophytes; shape analysis Introduction Osteoarthritis receives a great deal of attention in both palaeopathological and clinical studies due to its high frequency in human populations past and present (palaeopathological literature: Weiss & Jurmain, 2007; Waldron, 1991; Lieverse et al., 2006; clinical literature: McGonagle et al., 2010; Zhai et al., 2007; Hootman et al., 2003). Despite its prevalence, the aetiology of osteoarthritis continues to elude researchers. The main theories to date are biomechanical breakdown of the joint due to physical stress, degeneration associated with increasing age, and a genetic predisposition (Spector et al., 1996; Herrero-Beaumont et al., 2009; Molnar et al., 2009). Osteoarthritis can also develop as a consequence of acute injury; this condition is often referred to as ‘secondary osteoarthritis’, as opposed to ‘primary’ or idiopathic osteoarthritis (Honkonen, 1995; Cymet & Sinkov, 2006). It is now generally accepted that osteoarthritis is a multifactorial disease with multiple aetiological factors contributing to the overall degeneration or break-down of the joint structure (Spector & MacGregor, 2004; Weiss, 2006). Knee osteoarthritis is very common (Rogers et al., 1990; Weiss & Jurmain, 2007). Felson et al. (1987) found a prevalence rate of 44% in individuals over 80 years of age with knee osteoarthritis in the Framingham Heart Study cohort, USA. Osteoarthritis of the elbow has been considered uncommon, with clinical prevalence being reported at 1.3 – 7% (Dalal et al., 2007). However, elbow osteoarthritis has been found to be more prevalent in archaeological samples, with Debono et al. (2004) reporting 27% of individuals affected from a Medieval necropolis in Provence, France. This difference could be due to the condition being under-reported clinically, the use of different diagnostic * Correspondence to: K. A. Plomp, Department of Archaeology, Durham University, Dawson Building, South Road, Durham DH1 3LE, England e-mail: k.a.plomp@durham.ac.uk Copyright © 2013 John Wiley & Sons, Ltd. Received 4 January 2013 Revised 19 February 2013 Accepted 27 March 2013 International Journal of Osteoarchaeology Int. J. Osteoarchaeol. (2013) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/oa.2319