Is Osteoarthritis Age-Related?
While it is unfortunately true that certain types of arthritis do affect children, primary osteoarthritis is not among them. Children who have arthritis typically have juvenile idiopathic arthritis, juvenile spondylitis, lupus, Kawasaki's disease, or Still's disease -- but not primary osteoarthritis. "Primary" osteoarthritis is so-named because there is no underlying or predisposing cause to the disease. Certain congenital abnormalities or bone abnormalities that develop during growth can increase a child's risk of developing osteoarthritis later in life though.
Osteoarthritis is considered an age-related condition because prevalence increases with age. According to the Primer on the Rheumatic Diseases, osteoarthritis is uncommon before age 40, while most people over age 70 have radiographic evidence of the disease, even if they are experiencing no symptoms.
Which Special Conditions Cause Early-Onset Osteoarthritis?
Most problems that cause premature or early-onset osteoarthritis are mechanical in nature, and most often, involve the hip. When the signs and symptoms occur can be significant. If corrected before age 6, congenital hip dislocations are not associated with osteoarthritis. Another condition, known as Legg-Calve-Perthes disease, which affects children between the age of 4 and 9 years old is characterized by dead bone in the hip, similar to avascular necrosis, causing a pronounced limp. Surgery must be performed in these young patients to prevent the development of osteoarthritis in their early adult years.
Trauma is yet another cause of early-onset osteoarthritis. Children, who experience stress fractures during activities that are associated with heavy exercise, such as ballet, gymnastics, diving, soccer, cheerleading, and dance can fragment the epiphysis (bone growth plate). A fragmented epiphysis may be associated with premature osteoarthritis. There are other traumatic conditions that lead to avascular necrosis and ultimately early onset osteoarthritis including Kohler's disease, Freiberg's disease, Scheuermann's disease, and Osgood-Schlatter disease.
Certain genetic mutations have been linked to early-onset osteoarthritis. For example, genetic mutations associated with the underproduction of Type II collagen have been identified in families. Articular cartilage normally consists of a large amount of Type II collagen. This abnormality brings about osteoarthritis, typically in adolescence and typically involving the weightbearing joints (e.g., knees and hips). While researchers recognize that genetic mutations can cause a predisposition to osteoarthritis, identifying those mutations is no small task.
It is also known that abnormal development of the bone growth plate can cause deformed bones and premature development of osteoarthritis. Examples include people born with dislocated hips, dwarfism, or hypermobility or hyperelasticity syndromes such as Ehlers-Danlos, osteogenesis imperfecta, and Marfan's syndrome.
What Can Parents Do?
Doctors advise parents not to disregard their child's pain as "just growing pains". Parents must pay attention to the details, especially since children may be too young to accurately express the kind of pain they are exeperiencing, when it started, if it is constant, if it comes and goes. Parents should advise their pediatrician of any notable abnormalities so a proper evaluation can be performed by the doctor. Awareness of a problem, early diagnosis and early treatment may prevent a child from a lifetime of agony due to osteoarthritis later in life.
Primer on the Rheumatic Diseases. Thirteenth Edition. Klippel J. MD et al. Published by the Arthritis Foundation.
It's Not Just Growing Pains. Thomas J. A. Lehman, MD. Oxford University Press. Copyright 2004.
All About Osteoarthritis. Nancy E. Lane, MD and Daniel J. Wallace, MD. Oxford University Press. Copyright 2002.