Page 15 - The value of total hip and knee arthroplasties for patients

(12.700 men and 21.600 women) and 54.900 patients with knee OA (20.700 men 1 and 34.200 women). Based on demographic trends alone, the absolute number of
people with OA is expected to rise by almost 40 percent between 2011 and 2030.
In view of the expected rise in the number of severely overweight people (Body
Mass Index >30), the actual future prevalence of OA may be even higher.5
Risk factors for development and progression
OA is considered to be a multifactorial disorder,with both systemic and biomechanical factors influencing its development and progression.
Regarding systemic factors, overall the risk of developing OA increases with age, showing a peak around the age of 78 to 79 years.5 In addition, OA is more common among women than among men. Moreover, ethnicity and certain genetic factors were also found to play a role in the development of OA of the hip/or knee.6
Local,biomechanical factors can be subdivided into intrinsic- and extrinsic local factors. Examples of intrinsic local factors are: factors which affect the load-bearing capacity of the joint, (e.g. previous trauma, or septic and/or reactive arthritis), congenital factors (e.g. congenital hip dysplasia, Perthes disease and femoral epiphysiolysis and surgery (e.g. meniscectomy, muscular weakness and laxity). Examples of extrinsic local factors are: overweight, strenuous profession (much lifting, squatting and kneeling), spor ts (esp. top level spor ts like soccer or ballet) and prolonged squatting (which influence the actual load borne by the joint).6
Regarding risk factors for progression, overweight is more important as a risk factor for in knee OA than in hip OA, whereas higher age, female sex and radiographic severity at the time of diagnosis are major risk factors particularly for the progression of OA of the hip.7,8
Radiographic and clinical characteristics
Radiographic characteristics of OA include joint space narrowing due to cartilage loss, the presence of osteophytes, sclerosis of the subchondral bone, and the formation of cysts.The severity of radiographic OA can be assessed by means of the Kellgren and Lawrence classification.This method distinguishes 5 grades (0-4), with grade 2 or higher indicating the presence of radiographic OA.9
General introduction
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