The word, which Greek has “lent” the English literature, fully describes the condition: Osteonecrosis (or avascular necrosis) is the “death” of the bone, namely the subsidence of the articular surface due to the interruption of blood supply.
Although it may appear in any bone, the hip is the most frequently affected one. In fact, we are talking about the osteonecrosis of the femoral head. Data of the American Academy of Orthopedic Surgeons report that more than 200,000 patients are admitted to hospitals every year, most of them with a problem in both hips.
HIGH RISK GROUPS
Death of osteocytes, and thus the disturbance of the normal structure of the spongy bone, means that it loses its supportive capacity and recedes, creating a permanent deformity and early arthritis. In many patients, the diagnosis is confirmed at an age under 25 years, but the majority is found in the 35-45 age group. Men are three times as likely to present early arthritis, than women.
Hip injury, complications after surgery, and slipping of the femoral head during childhood, are considered the main traumatic factors of the disease. A study published in the Journal of Medical Genetics in 2016, suggests that a new genetic mutation in the TRPV4 gene, which plays an important role in controlling the flow of blood and bone cell growth, may be responsible. However, non-traumatic factors in the literature mainly include chronic corticosteroid use, alcoholism, diving, systemic lupus erythematosus, sickle cell anemia, and high cholesterol.
WHICH ARE THE SYMPTOMS?
Osteonecrosis develops gradually. Pain in the groin and / or the inner-anterior side of the thigh is the first typical symptom. As the disease progresses, it becomes more and more difficult for the patient to stand, while movement in the joint is limited and very painful. This may take a few months to over a year. Studies have shown that early diagnosis is important, because treatment has better results and, above all, can prevent osteoarthritis. In fact, an MRI can even show the beginning of osteonecrosis, before the pain is yet to appear.
WHICH IS THE BEST TREATMENT?
Although the orthopaedist may recommend a medication and using crutches to relieve pain, treating osteonecrosis is exclusively surgical. As long as the femoral head is still spherical, namely at the early stage of the disease, an attempt for revascularisation is made. The most popular procedure is through the creation of holes, in order to decompress and create space for the development of blood vessels and the placement of bone grafts.
A more complicated procedure is the one in which a part of the fibula is taken, which, along with the corresponding vessel, is placed on the femoral neck and head. However, if the head has lost its shape or arthritis has already been generated, then total hip replacement (arthroplasty) is applied, namely, the damaged joint is replaced with an artificial one.