VOL. 90-B, No. 4, APRIL 2008 411  ASPECTS OF CURRENT MANAGEMENT The assessment of early osteoarthritis T. C. B. Pollard, S. E. Gwilym, A. J. Carr From the Nuffield Orthopaedic Centre, Oxford, England  T. C. B. Pollard, BSc(Hons), MRCS, Specialist Registrar & Botnar Surgical Research Fellow  S. E. Gwilym, MRCS, Specialist Registrar & Girdlestone Research Fellow  A. J. Carr, ChM, FRCS, Nuffield Professor of Orthopaedic Surgery Nuffield Department of Orthopaedic Surgery University of Oxford, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford OX3 7LD, UK. Correspondence should be sent to Mr T. C. B. Pollard; e-mail: Tom.Pollard@ndos.ox.ac.uk ©2008 British Editorial Society of Bone and Joint Surgery doi:10.1302/0301-620X.90B4. 20284 $2.00 J Bone Joint Surg [Br] 2008;90-B:411-21. Treatment strategies for osteoarthritis most commonly involve the removal or replacement of damaged joint tissue. Relatively few treatments attempt to arrest, slow down or reverse the disease process. Such options include peri-articular osteotomy around the hip or knee, and treatment of femoro-acetabular impingement, where early intervention may potentially alter the natural history of the disease. A relatively small proportion of patients with osteoarthritis have a clear predisposing factor that is both suitable for modification and who present early enough for intervention to be deemed worthwhile. This paper reviews recent advances in our understanding of the pathology, imaging and progression of early osteoarthritis. As the burden of osteoarthritis (OA) rises with increased life expectancy, the need to address diseases of the elderly becomes more pressing. Between 1991 and 2000, the number of pri- mary total hip replacements being undertaken in England increased by 18%, and the number of primary knee replacements more than doubled. 1 Revision hip and knee arthroplasty increased by 154% and 300%, respectively, 1 over this period, and projections to 2010 for primary hip and knee arthroplasty estimate increases of 22% and 63%, respectively. 1 Longer term projections of primary hip and knee arthroplasty in the United States from 2005 to 2030 predict an increased demand of 174% and 673%, respectively. 2 Whereas arthroplasty is usually successful in relieving pain and improving function, it has inherent disadvantages compared with treatment that preserves the joint. Investigation of the cost- effectiveness of early treatment to preserve the natural joint is both worthwhile and necessary. Unfortunately, progress has been hampered by a number of major obstacles that make it diffi- cult to design new treatments and assess their outcome. Our understanding of the early pathology of OA is poor, particularly in terms of reliable assays or biomarkers. Human tissue suitable for study is difficult to obtain. The tissue commonly studied is often obtained as macroscopically less-involved cartilage from patients undergoing arthroplasty. Such tissue may have been altered by previous medical treatment. 3 There are no good animal models of chronic disease, and the validity of animal models that use a single injury to initiate OA is questionable. From a clinical perspective, dis- ease progression is traditionally monitored with radiography, 4 but its correlation with symptoms in early disease is poor. Longitudinal studies that rely on plain radiographs to evalu- ate treatments are difficult, as measurable pro- gression is slow and not universal. Moreover, they require trial periods of at least two years in large cohorts of patients. Little treatment is available for early OA. Surgical options to reduce or prevent disease progression may aim to restore normal anat- omy, eliminate biomechanical factors, or resur- face isolated cartilage defects by grafting. The development of disease-modifying drugs has been disappointing, failing to replicate their success in rheumatoid arthritis and with none meeting food and drug administration (FDA) approval for clinical practice. 5 Clinical trials of drugs in advanced OA aimed at matrix regen- eration or preservation have not been success- ful, at least not using a single agent. This may well be because the mechanical environment remains abnormal and hostile to cartilage regeneration. 5 Sensitive techniques that could detect early OA and reliably monitor its progression would identify patients who may benefit from joint preserving intervention for entry into clinical trials, thereby aiming to reduce the number of patients needing arthroplasty. The identifica- tion of those subjects who are likely to progress rapidly would be particularly useful when designing trials. This review outlines recent Aspects of current management