Hip Arthritis

Hip Arthritis is properly defined as inflammation of the hip joint. More specifically, arthritis is due to wear down of the smooth, critical cartilaginous surfaces of the hip. When the cartilage breaks down in the hip, the joint starts seeing increased stress during activity because it’s not as well protected. As a result, the joint lining, which is called the synovium, forms extra joint fluid to try to better lubricate the joint and bring in inflammation to the joint.

The classic symptoms of hip arthritis are:

1. Hip pain that is exacerbated with activity. Difficult activities include sitting or walking for long periods of time, getting out of a chair or out of a car or putting shoes on, and challenges with climbing stairs.
2. Stiffness with limited range of motion especially when waking up in the morning and tends to get better with motion
3. Swelling and warmth around the joint
4. Patients may also notice a sensation of crepitus which is a crunching or grinding sensation due to the irregular cartilage surface. You can think about this as a road which has potholes making driving along the road not as smooth as you would like.

Pain can be in several different areas of the hip depending on where the cartilage breakdown was seen but most commonly, patients point to the groin area when there is an issue within the actual hip joint. However, it is not uncommon for patients to point to the side of the hip or even the buttock area in the context of hip arthritis.

There are several different causes of hip arthritis which include:

1. Traditional (idiopathic) osteoarthritis without a previous injury or an underlying disorder
2. Hip dysplasia: Patients who endorse a pediatric history of hip disorders such as developmental dysplasia of the hip (DDH), slipped capital femoral epiphysis (SCFE), or Legg-Calves-Perthes disease (LCP) are at increased risk of developing degenerative changes of the hip later in their life despite appropriate treatment during their development.
3. Femoroacetabular impingement (FAI): This special type of hip pathology is due to either a deformity of the normally spherical femoral head into a more oblong shape (Cam deformity) and/or when the acetabulum has excessive coverage over the femoral head and actually pinches the labrum during motion (Pincer deformity). If untreated, this condition progresses damages the labrum which then leads to breakdown of the cartilage.
4. Inflammatory arthritis secondary to rheumatologic causes such as rheumatoid arthritis or psoriatic arthritis
5. Post-traumatic arthritis after an injury such as a hip fracture that may have been treated with surgery or a hip dislocation that caused damage to either the femoral head or acetabulum.
6. Avascular necrosis which is due to loss of blood supply to the femoral head and causes progressive collapse of the head. This collapse leads to an irregular joint surface and rapid progression of cartilage breakdown and symptomatic arthritis.
7. Septic arthritis due to an underlying infection of the joint, this represents an orthopedic emergency to thoroughly remove the infection.

For patients without a secondary reason for why they’re having their arthritis, most commonly this breakdown of the cartilage is due to the natural wear and tear on the cartilage over a lifetime of use. We know that genetics and family history is very important as many patients will remember that their parents or other family members dealt with similar issues of arthritis either in the hip or in a different joint. So the family history and just natural wear and tear are the most common presentation of this breakdown of the cartilage that we see as orthopedic surgeons. Additionally, increased body weight puts more load on the joint as well as repetitive stresses on the hip due to a patient’s occupation such as heavy manual labor or athletes with previous injuries to the hip capsule, labrum, or cartilage

If a patient is concerned about having hip arthritis, this is first confirmed on their history because many patients will have the symptoms that we have already outlined above. A physical exam would help by determining general joint mobility, help to localize the pain, and consider other causes of pain around the hip such as greater trochanteric pain syndrome, piriformis syndrome, lumbar radiculopathy, or even referred knee pain to the hip. Radiographs (x-rays) are essential to look at joint space narrowing due to the breakdown of the cartilage, osteophyte (bone spur) formation, and white sclerosis of the bone due to the increased stress on the bone. Radiographs also helps in deformity detection and planning such as an extremely worn down hip socket (Acetabular Protrusio), deformity of the femoral head (Cam deformity, post-AVN), or deformities due to prior fracture or surgery.

Advanced imaging with MRI and CT are not required for the pure diagnosis of hip arthritis but may have utility in other hip conditions such as FAI. CT may have some benefit in delineating hip deformity and for preoperative planning of a hip replacement but is not required as high quality X-rays are often enough to tell the full story.