Osteoarthritis (OA) research continues to grow in parallel with the increasing needs related to our ageing populations. This presentation will select highlights from the substantial recent literature to provide an update on current concepts of pathogenesis and treatment. The substantial impact on people with OA is again recognised with studies demonstrating the inadequacy of pain relief despite using prescribed medication.
In terms of pathogenesis, genetic association studies have demonstrated new loci associated with both hip and hand OA. Elegant animal model studies have provided insights and possible targets for novel interventions. There has been a focus on the role of transforming growth factor-B in recent years, and increased levels have been found in the subchondral bone of surgically induced murine OA, with inhibition of this activity reducing cartilage loss. Recent TGFB has been linked to increased levels of nerve growth factor (NGF) expression in chondrocytes, providing new thoughts on potential pain sources in the joint.
The growing and essential focus on early detection of OA has been strengthened not only with new imaging studies detailing the importance of MRI pathologies seen before radiographic OA is visible, but with potential citrullinated biomarkers for early diagnosis and discrimination from inflammatory arthritis. Pain on climbing stairs has been reported as the first clinical complaint for those developing knee pain, a first step toward feasible identification of people requiring early intervention.
The use of modern imaging continues to provide insights into the temporal progression of OA structural change, with MRI and ultrasound tools continuing to evolve. The importance of bone shape is rapidly emerging in recent literature. 2D estimation of femoroacetabular impingement and acetabular dysplasia have predicted subsequent hip OA and hip replacement. Quantitative 3D bone shape not only predicts onset of radiographic OA but provides a more responsive biomarker of OA progression than X-rays or MRI cartilage measures.
Use of current OA pharmacological therapies has been reported with relatively consistent use of analgesic drug classes across Europe, though with some variation in opioid use. Up-to-date evidence synthesis has underpinned revised OA management recommendations from OARSI and NICE (UK). The importance of non-pharmacological interventions is highlighted in these guidelines. While short-term weight loss is an effective therapy for OA knee pain, the benefits of maintaining this weight loss over a year with some sort of minimal intervention programme has been demonstrated in a RCT. Comparing the relative efficacy of our available therapies has been done using a network meta-analysis. The last year has also again highlighted the toxicity of common therapies, with NSAID problems (including lack of concomitant gastro-protection) reported in a large study, and even the side-effects of paracetamol reconsidered in observational cohorts.
New therapies for human OA remain few. New evidence supporting the analgesic efficacy of anti-nerve growth factor monoclonal antibodies has been provided with another RCT employing tanezumab; managing potential side effects of this class remains problematic. Structure modification remains challenging. New data on bisphosphonates again raises the question of the potential for treating subchondral bone. A Phase II RCT of the iNOS inhibiter cindunistat failed to demonstrate radiographic or symptomatic benefits. A dose-ranging RCT of intra-articular recombinant human fibroblast growth factor failed to achieve its primary MRI cartilage endpoint, though some secondary cartilage benefits were reported.
Surgical interventions continue to provide lessons for OA therapies. Effective surgical (or maybe effective analgesic) therapy may improve OA patient survival, with a study demonstrating a cardioprotective effect of primary joint replacement. Joint distraction, a fascinating model for structure modification has been reported in a canine OA model, though benefits were not as evident as those reported from human studies – this also highlights the longstanding problems related to appropriate interpretation of OA animal models.
Disclosure of Interest None declared