What is Hip Osteonecrosis

Hip Osteonecrosis, also known as avascular necrosis of the hip, represents a condition caused by reduced blood flow to the femoral head secondary to a variety of risk factors such as a traumatic event, sickle cell disease, steroid use, alcoholism, autoimmune disorders, and hypercoagulable states. Avascular necrosis may also occur in different bones, but most commonly involves the femoral head.

Impairment of the blood supply to the head in the hip causes the bone under the cartilage to weaken and the cartilage to collapse. As the head loses its roundness, the harmony of the hip joint deteriorates and arthrosis occurs. As a result, decreased hip movements and pain occur.

It is more common in men. It is commonly seen between the ages of 35-50. 80% of both hips are affected together. In 3% of the patients, avascular necrosis is also seen in other bones except the hip.

What are the Causes of Hip Osteonecrosis?

Although the exact cause of the blood circulation disorder that causes hip avascular necrosis is not certain, there are certain risk factors.

• Damage to the hip joint increases the risk of avascular necrosis. The blood supply of the femoral head may be impaired as a result of dislocation of the hip, hip head fractures or high-energy accidents without a fracture cause.
• Alcoholism
• Long-term steroid use
• Hematological diseases (leukemia, lymphoma)
• Dysbaric disorders - Caisson disease
• Sickle cell anemia
• Coagulation disorders
• Viral diseases (such as HIV, Hepatitis, CMV)
• Rheumatic diseases (Lupus)
• Transplant patients
• Marrow-replacing diseases (e.g. Gaucher's disease)
  

However, the causative factor cannot be determined in 37% of the patients.

How is Hip Osteonecrosis Diagnosed?

Initially there is vague hip pain. As the load increases, the pain increases, and over time, joint deterioration occurs and hip joint movements are restricted. Hip MR imaging is very useful for early diagnosis. In the middle/late disease stage, the diagnosis can be made by X-ray.

What Are the Stages of Hip Osteonecrosis?

Ficat-Arlet Staging, which is the most commonly used radiologically, is important for planning the treatment.

Stage 1: Direct radiographs are normal, there is avascular necrosis on MRI

Stage 2: Sclerosis and cysts are also present on direct radiographs

Stage 3: Subchondral fracture occurs in the necrotic area, there is a crescent sign

Stage 4: Femoral head collapse and arthrosis

The aim of surgeries in the hip joint is to stop the progression of the disease before the femoral head collapses. Generally, if the stage of the disease is stage 3 or more, the success rate of hip conserving surgeries is low. The smaller the area involved in the femoral head and the earlier the disease, the better the results of joint sparing surgery.

How is the Treatment of Hip Osteonecrosis?

In the treatment, especially at the beginning of the disease, rest, painkillers, activity changes and exercises to stretch the hip joint capsule may be beneficial. Since the disease is progressive, surgical options to slow down this progression give very successful results in early stage diseases.

Core Decompression

The purpose of this procedure is to reduce the pressure that prevents feeding in the head of the hip. By reaching the bone through a small incision made on the side of the hip, either a single large hole or 3-4 small holes are opened in the hip, reducing the pressure of the affected area and blood supply is expected again. It is a treatment with a very high success rate, especially in the first 2 stages, and it can prevent the head of the hip from collapsing. It is an operation that takes about 30-45 minutes. Patients can be discharged on the same day or 1 day later. Patients are asked not to put any weight on their hips for 6 weeks after surgery. During this period, patients can move with crutches.

Stem Cell / PRP

It is mostly applied together with the core decompression process, not alone. In the hip where core decompression is applied, there is bleeding into the bone, but stem cells and PRP to be applied in order to increase new bone formation increase the healing rates.

Bone Graft

With core decompression surgery, bone tissue to be taken from another part of the body is placed through the drilled hole and is expected to support new bone formation. After the stem cell application, it started to be less preferred.

Vascularized Fibula Graft

It is similar to the bone graft application, the difference is that a piece of fibula in the leg taken together with its veins and arteries than placed in the hole opened with core decompression. The success rate is slightly higher than normal bone graft in very experienced hands. It has disadvantages such as a certain degree of numbness and scarring in the area where the bone is taken, and a long operation time.

Total Hip Replacement

If hip osteonecrosis progresses to the last stage and the joint shape is completely deteriorated and severe pain and limitation of movement due to arthrosis. Someteimes arthrosis makes it impossible to perform daily activities, the last choice to be preferred is total hip replacement surgery. In total hip replacement surgery, the damaged joint surfaces are completely replaced. A new articular surface made of metal, ceramic or polyethylene (plastic) material is made for the patient.