Degenerative Osteoarthritis (Oa)
Degenerative osteoarthritis (OA) is the most common disease process resulting in the need for a Total Hip Replacement (THR). Degenerative Osteoarthritis is a progressive joint disease that affects people’s ability to move their hip joint without pain. While OA is more common as we age, not everyone develops OA. There are two types: primary and secondary. While the symptoms are the same for the both types, the underlying cause is different
Secondary Degenerative OA
Secondary Degenerative OA is the result of a prior trauma or an underlying condition that altered the hip’s normal architecture, resulting in joint deterioration and arthritis. Often subtle congenital or early childhood abnormalities are present which are slowly progressive and the person may not have even been aware of the condition until the hip became symptomatic many decades later.
In our practice, the vast majority of hips with degenerative OA are secondary to an underlying condition. We commonly see patients who had developmental conditions at birth, such as hip dislocation or subluxation, or who developed conditions during childhood when their skeletons were still maturing.
Some people are born with subtle abnormalities in the hip socket area that cause the femoral head or femoral neck to “bump” into the rim of the socket when they move. This can damage the rim and lead to arthritis. This condition is referred to as acetabular femoral impingement (FAI) and is a common cause of secondary OA.
Prior hip trauma with or without a fracture, failed prior surgery on the hip, autoimmune inflammatory conditions like rheumatoid or psoriatic arthritis, loss of the blood supply to the femoral head as an adult (AVN or osteonecrosis) or as a child (Legg-Perthes disease) or a slipped capital femoral epiphysis all are common conditions leading to a diagnosis of secondary OA and the need for a total hip replacement (THR) later in life.
Primary Degenerative OA
Primary Degenerative OA, a less common condition, occurs when hips develop degenerative arthritis without a clear underlying cause. A genetic basis is often assumed, as many times patients report other members of their family developing OA and needing THR.