PT  - JOURNAL ARTICLE
AU  - Chen, Lianzhi
AU  - Yao, Felix
AU  - Wang, Tao
AU  - Li, Guangyi
AU  - Chen, Peilin
AU  - Bulsara, Max
AU  - Zheng, Jessica Jun Yi
AU  - Landao-Bassonga, Euphemie
AU  - Firth, Marty
AU  - Vasantharao, Praveen
AU  - Huang, Yigang
AU  - Lorimer, Michelle
AU  - Graves, Stephen
AU  - Gao, Junjie
AU  - Carey-Smith, Richard
AU  - Papadimitriou, John
AU  - Zhang, Changqing
AU  - Wood, David
AU  - Jones, Christopher
AU  - Zheng, Minghao
TI  - Horizontal fissuring at the osteochondral interface: a novel and unique pathological feature in patients with obesity-related osteoarthritis
AID  - 10.1136/annrheumdis-2020-216942
DP  - 2020 Jun 01
TA  - Annals of the Rheumatic Diseases
PG  - 811--818
VI  - 79
IP  - 6
4099  - http://ard.bmj.com/content/79/6/811.short
4100  - http://ard.bmj.com/content/79/6/811.full
SO  - Ann Rheum Dis2020 Jun 01; 79
AB  - Objectives Obesity is a well-recognised risk factor for osteoarthritis (OA). Our aim is to characterise body mass index (BMI)-associated pathological changes in the osteochondral unit and determine if obesity is the major causal antecedent of early joint replacement in patients with OA.Methods We analysed the correlation between BMI and the age at which patients undergo total knee replacement (TKR) in 41 023 patients from the Australian Orthopaedic Association National Joint Replacement Registry. We then investigated the effect of BMI on pathological changes of the tibia plateau of knee joint in a representative subset of the registry.Results 57.58% of patients in Australia who had TKR were obese. Patients with overweight, obese class I & II or obese class III received a TKR 1.89, 4.48 and 8.08 years earlier than patients with normal weight, respectively. Microscopic examination revealed that horizontal fissuring at the osteochondral interface was the major pathological feature of obesity-related OA. The frequency of horizontal fissure was strongly associated with increased BMI in the predominant compartment. An increase in one unit of BMI (1 kg/m2) increased the odds of horizontal fissures by 14.7%. 84.4% of the horizontal fissures were attributable to obesity. Reduced cartilage degradation and alteration of subchondral bone microstructure were also associated with increased BMI.Conclusions The key pathological feature in OA patients with obesity is horizontal fissuring at the osteochondral unit interface. Obesity is strongly associated with a younger age of first TKR, which may be a result of horizontal fissures.