December 6, 2022
What is hip arthritis?
Degenerative joint disease or “arthritis” of the hip is extremely common among our population, affecting about 90 per 100,000 people per year. It is essentially the progressive loss of the hip joint cartilage which normally allows smooth motion of the hip joint in multiple directions. There are several etiologies which can cause a hip to be affected with arthritis. These include increased age, genetic factors, direct injuries to hip structures such as the labrum or cartilage, fractures of the femoral head or acetabulum (socket), high impact activities over a long period of time, structural abnormalities of the femoral head and acetabulum (which could be congenital or acquired) such as acetabular dysplasia, femoroacetabular impingement, Legg-Calve-Perthes Disease, Slipped Capital Femoral Epiphysis, or avascular necrosis of the femoral head.
With progressive cartilage loss in arthritis, the joint surfaces of the hip experience abnormal contact forces and pressures, and the hip synovial tissue becomes inflamed. Over time, abnormal remodeling of the bone occurs, with hardening of the subchondral bone below the cartilage, and formation of bone cysts, and spurs (osteophytes).
Unfortunately, hip arthritis is typically progressive and irreversible, and can cause symptoms of pain and limited mobility and range of motion. The pain is commonly localized to the groin region on the front of the hip, but can also present with pain towards the outside of the hip, in the buttock region, or radiate down to the knee.
Do I have to have a hip replacement?
Not everyone with hip arthritis “needs” a hip replacement. The severity of the arthritis on the x-rays, and the symptoms typically guide our decision on whether a hip replacement would be a good treatment option. Typically, with mild severity of arthritis on x-rays and mild to moderate symptoms, we prefer to begin with non-surgical treatment options which include:
- Activity Modification. An emphasis on low impact aerobic exercise (biking, swimming, elliptical, etc), and avoiding high impact weight bearing activities (eg. heavy leg weight lifting) is important in minimizing the symptoms of pain from hip arthritis.
- Physical therapy, which can be beneficial in strengthening the dynamic stabilizing muscles around the hip, and stretching to improve mobility and range of motion. This could be quite effective at alleviating pain and improving mobility for those with milder severity of hip arthritis.
- Non-steroidal anti-inflammatories and oral analgesics – These can help decrease the inflammation in the hip joint and offer comfort and pain control with activities. These medications can have side effects, and depending on the person’s medical history they may or may not be an option.
- Image-guided hip injections – Most commonly, corticosteroid injections can be administered using ultrasound or x-ray guidance to accurately reach the joint space. These injections can serve to alleviate pain from the inflamed hip joint, and may be effective, depending on the severity of the arthritis.
Am I a good candidate for a hip replacement?
This is a very common question that we get from our patients who suffer from hip arthritis. An example of an ideal candidate for a hip replacement is someone with advanced, severe arthritis of the hip on imaging, who also has severe symptoms of pain and limited mobility, which significantly affects their activities and overall quality of life. They typically have already tried non-surgical treatment options, which may have failed to provide durable pain relief and improved quality of life. Of course, they need to also be medically fit and safe to undergo surgery.
What type of implants are used in a hip replacement?
A hip replacement is typically comprised of 4 parts:
- The acetabular cup, which is usually a metal alloy cup that is implanted into the socket after removal of the diseased bone and cartilage. This cup typically has a porous metal surface on the back, which is in contact with the bone, and allows for bone ingrowth to hopefully provide life-long fixation.
- The acetabular liner, which is commonly made of polyethylene material, and is locked into the inside of the acetabular cup. This is part of the bearing surface of the artificial hip joint. There are several different types of liners that may be used depending on anatomy, age, and hip stability.
- The femoral stem, which is a metal device, implanted inside the canal of the femur, after removal of the arthritic femoral head. These can be cementless or cemented, depending on the bone quality and density. Cementless stems, like cementless cups, have a porous metal architecture that allows for bone ingrowth. Cemented stems, are bonded to the inside of the femoral canal using bone cement. Those are typically used in the setting of weak bone quality.
- The femoral head, which is a spherical head made of ceramic or metal and is placed onto the stem, and articulates with the liner that is inside of the cup. The femoral head and the liner are the bearing surface of the artificial hip joint.
What is the best approach for a hip replacement?
The best approach for performing a hip replacement is the approach that the surgeon you are seeing is comfortable executing to perfection. Every approach, whether anterior, posterior or lateral, has advantages and disadvantages. Minimally invasive techniques that minimize soft tissue releasing and dissection can be applied to most of these approaches. Ultimately, a hip replacement can be done very successfully using any of the multiple approaches that exist, and surgeon familiarity and comfort in seamlessly and safely executing the approach is the most important aspect.
What new technologies exist in hip replacement?
There have been exciting advances in the field of hip replacement over the past decade.
The implant designs and instruments used to prepare the bone for the implants have improved greatly since the earlier hip replacements in the mid 1900s. The implants have evolved to become more bone preserving, with successfully high rates of durable fixation, and the instrumentation has allowed us to perform the surgery through more minimally invasive, soft-tissue sparing techniques.
The use of enabling technology such as computer navigation, intra-operative fluoroscopy / x-ray, or robotics have also become more widely used in certain situations, to guide component positioning, and accurate restoration of hip length and offset. A hip replacement does not necessarily have to be performed robotically to achieve an excellent outcome. Ultimately, as with any surgical technique, the most important aspect is the surgeon’s comfort, familiarity and ability to seamlessly perform the surgery.
About Omar Behery, MD, MPH
Dr. Omar Behery is a fellowship-trained orthopedic surgeon specializing in minimally invasive hip and knee replacement as well as complex and revision hip and knee reconstruction.
A medical graduate of Rush Medical College, Dr. Behery went on to complete his orthopedic surgery residency training at NYU Langone Orthopedic Hospital (Hospital for Joint Diseases) in New York. He then further specialized in adult hip and knee joint reconstruction, by completing his fellowship training at the OrthoCarolina Hip and Knee Center, in Charlotte.