Osteoarthritis

Osteoarthritis (OA) is the most common joint disorder, is associated with an increasing socioeconomic impact owing to the ageing population and mainly affects the diarthrodial joints. Primary OA results from a combination of risk factors, with increasing age and obesity being the most prominent. The concept of the pathophysiology is still evolving, from being viewed as cartilage-limited to a multifactorial disease that affects the whole joint. An intricate relationship between local and systemic factors modulates its clinical and structural presentations, leading to a common final pathway of joint destruction. Pharmacological treatments are mostly related to relief of symptoms and there is no disease-modifying OA drug (that is, treatment that will reduce symptoms in addition to slowing or stopping the disease progression) yet approved by the regulatory agencies. Identifying phenotypes of patients will enable the detection of the disease in its early stages as well as distinguish individuals who are at higher risk of progression, which in turn could be used to guide clinical decision making and allow more effective and specific therapeutic interventions to be designed. This Primer is an update on the progress made in the field of OA epidemiology, quality of life, pathophysiological mechanisms, diagnosis, screening, prevention and disease management

Simulated mark-recovery for spatial assessment of a spiny lobster (Panulirus argus) fishery

•We simulate scenarios representing spiny lobster distribution at Glover's Reef Marine Reserve, Belize.•We examine how no-take reserves bias stock assessments that rely solely on fishery-dependent data.•We evaluate whether a mark-recovery design can be robust to uncertainty about transfer rates between fished and non-fished areas.•Fishing mortality can usually be accurately estimated by mark-recovery without prior knowledge of fish transfer rates.Marine reserves are becoming widely implemented along with conventional fisheries controls as integrated approaches to fisheries management. The restricted spatial distribution of fishing effort, relative to the spatial distribution of fish stocks that may be partially protected by marine reserves, often necessitates spatial considerations in the design of monitoring and stock assessment. Simulation modeling was used to evaluate whether a mark-recovery design could be used to accurately estimate fishing mortality rates without information about movement rates being available to the assessment procedure. A spatially-explicit individual-based simulation was developed with environmental characteristics of Glover's Reef Marine Reserve, Belize and with biological characteristics of a fished population of Caribbean spiny lobster (Panulirus argus). Accuracy of fishing mortality estimates depended on whether these estimates were calculated for the fished area only or for the entire stock. Stock-wide fishing mortality estimates could usually be obtained that were robust to uncertainty about dispersive movement. We discuss results in the context of managing fisheries based on the status of fished areas alone or on the entire stock and discuss the necessity for information about fish movement for accurate assessment of stocks managed using marine reserves