Hip
Hip Pain and Conditions
The hip is a ball-and-socket joint that functions as a ball bearing. This design allows the hip to flex, extend, move from side to side (called abduction and adduction), and rotate (called internal rotation and external rotation). Although not quite as complex as the knee, the hip joint does its job wonderfully and allows us to get around with surprising agility (when it works properly).
However, when the bone and/or cartilage of the hip become diseased or damaged, the joint can stiffen and become very painful. While many hip conditions can be treated through conservative methods, surgery is often needed because of the excessive weight placed on the joint while walking, standing, and performing other regular activities.
At Orthopaedics New England, our surgeons provide state-of-the-art medical and surgical solutions for problems of the hip. Learn more about the hip below and treatments we provide for hip diseases.
To schedule an appointment with one of our orthopedic hip surgeons, call (203) 598-0700 or use our online form. We have three offices to serve you in Middlebury, New Milford, and Farmington, Connecticut.
Hip Anatomy
Ball and Socket: Your hip is a ball-and-socket joint. The top of the thighbone (femur) is shaped like a ball (femoral head). The ball fits into a cup-shaped socket (acetabulum) in the pelvis bone. The socket holds the ball in place and allows it to rotate during motion.
Articular Cartilage: Normally the ball and socket are very smooth, and both sides of the joint (as with most joints in the body) are covered with a thin, smooth layer of cartilage called articular cartilage that lubricates the bones and allows them to move easily. It is analogous to having Teflon that coats a frying pan.
When arthritis occurs, the joint becomes inflamed and the smooth cartilage surface begins to deteriorate. When that smooth coating wears down, it leaves the underlying bone surface exposed. This is where the term “bone-on-bone” arthritis comes from.
The surface becomes increasingly rough and large spurs called osteophytes may form around the joint. The bone around the joint may also develop cysts that fill with joint fluid. Eventually, the bone surfaces begin to erode as arthritis worsens.
Acetabulum: The socket itself (acetabulum) can sometimes be formed incorrectly. Most commonly, this happens if the socket is too shallow and the hip has a tendency to “pop out” or dislocate as an infant. This condition is known as hip dysplasia.
Even if the hip does not ever completely dislocate, a shallow acetabulum can cause problems years or even decades later. This is a common reason for adults to wear out their hip joint at an early age and require surgery.
Labrum: There is a cartilage “bumper” or gasket that surrounds the rim of the socket, called the labrum. This gasket can develop tears and cause problems, typically in the form of mechanical difficulties and pain from the torn piece (a labral tear).
The ball of the femoral head is supplied with blood from several sources. Injuries to this blood supply such as a traumatic hip dislocation, or clotting disorders that prevent blood flow in this region such as sickle cell disease, can lead to a loss of bone, called avascular necrosis.
The hip joint is surrounded by a tough covering called the capsule. Hip joint injections are placed inside this capsule. Similarly, hip infections often involve the joint fluid and space within the capsule. In addition, loose bodies or small nuggets of bone or cartilage are usually found in this joint space within the capsule.
If this capsule becomes contracted and tight, either with disuse or aging, it can lead to a flexion contracture of the hip where it is difficult to fully lay the leg flat while laying down. This often requires a release at the time of hip surgery to restore range of motion.
The prominent bony area over the side of the hips is called the greater trochanter. The bursa is a small sac that fits between muscle layers and helps them slide smoothly over one another, similar to two layers of plastic wrap with olive oil in between.
The most common cause of pain over the side of the hip is from trochanteric bursitis (inflammation of the bursa), which causes pain when pressing on or laying on the side of the hip.
Hip Diseases
Osteoarthritis is the most common cause of hip pain. Other causes of hip pain include trochanteric bursitis, hip fractures, labral tears, rheumatoid arthritis, avascular necrosis, and tumors.
Bursitis is inflammation of the bursa, or sac between muscle layers over the lateral side of the hip. It is often associated with weight gain, injury, or repetitive motion activities such as running. This type of bursitis is usually treated with weight loss, anti-inflammatory medications, muscle massage, stretching and physical therapy, and possibly steroid injection.
There are a number of different fractures that can involve the hip and pelvis, and many of these require surgery to fix and stabilize the bone. Hip fractures are common in elderly patients, who often have osteoporosis and sustain fractures with falls.
The hip socket (acetabulum) has a cartilage “bumper” or gasket that surrounds the rim of the socket, called the labrum. If this gasket tears, the torn cartilage may not heal on its own, leading to groin pain and mechanical symptoms such as locking and catching in the hip joint. Some tears may eventually heal on their own while others require surgery to remove the torn fragment of cartilage that is caught inside the joint.
This type of arthritis is caused when the body’s own immune system attacks the joints, leading to large, swollen joints that are painful, reddened, and warm. Rheumatoid arthritis typically causes pain in many joints.
If left untreated, inflammation within the joints leads to destruction of the cartilage in the joint. While newer rheumatologic medications have led to a remarkable decrease in the number and severity of rheumatoid patients that require orthopedic surgery, the disease still accounts for many joint replacements surgeries each year.
Also called osteonecrosis, this potentially devastating condition occurs when the femoral head (the ball at the top of the thigh bone) begins to die and collapse due to lack of blood supply. Avascular necrosis can be the result of trauma (dislocated or fractured femur), long-term corticosteroid use, chronic alcohol use, clotting diseases, sickle cell disease, chemotherapy or radiation treatment for cancer, environmental factors, or metabolic diseases.
Although AVN can affect people of any age, most are between ages 30 and 50. This debilitating disease usually leads to osteoarthritis of the hip joint and is one of the most common reasons for hip replacement surgery in young patients.
Bone tumors in the hip most commonly occur due to cancer that has metastasized. The five types of cancer that most often spread to bone include breast, lung, thyroid, prostate, and kidney cancer. These tumors can cause fractures of the femoral neck (the part of the femur just below the ball).
