Background & Etiology
The hip joint is one of the largest joints in the body. It is composed of one osseous (bony) joint. The hip is built for weight bearing and movement in several different planes. Most of the stability of the hip is derived from the joint design, joint capsule, ligaments, muscle and a cartilaginous tissue called the labrum.
Bone and Joint
The hip, like the shoulder, is a ball and socket joint. It is formed by the head of the femur (thigh bone), which sits in the acetabulum, a part of the pelvis. The head of the femur is a large ball and the acetabulum is a shallow socket. This design of the joint allows for greater mobility.
The bony joint surfaces of the head of the femur and acetabulum are covered with articular cartilage. The articular cartilage has a smooth and shiny surface that allows the ends of the bones to slide freely over each other. This is what enables the joint to move smoothly.
Arthritis is the wearing, degeneration or loss of articular cartilage in a joint. The three most common types of joint arthritis are osteoarthritis, rheumatoid arthritis, and traumatic arthritis. The most common cause of hip pain is arthritis. These different types of arthritis can damage the hip joint so much that it functions very poorly and becomes very painful. In these cases, a hip replacement may be necessary.
The most common conditions that lead to a hip replacement are osteoarthritis, Rheumatoid Arthritis, and traumatic arthritis.
The most common form of hip arthritis is Osteoarthritis. Osteoarthritis is a gradual wearing down and degeneration of the joint surfaces or articular cartilage. Osteoarthritis is most common in people who are middle age or adults over the age of 50, and people who are overweight. Women are more likely to develop osteoarthritis, which can affect one hip or both. Hip osteoarthritis is the most common cause of disability.
Unlike other forms of arthritis, rheumatoid arthritis is a systemic autoimmune disease that is not caused by common wear and tear on the joint. This condition usually affects joints symmetrically (for example, both knees, both wrists, both shoulders). Rheumatoid arthritis causes degeneration of the articular or joint cartilage. It can also affect the tissue that surrounds and lubricates the joint (synovium). If the joint surfaces and cartilage are not lubricated they can start to rub, causing the wear that leads to arthritis pain.
Rheumatoid arthritis can affect other parts of the body including organs like the heart and lungs, and can even cause fatigue. The cause of Rheumatoid arthritis is not fully known. It is considered an autoimmune disease where the cells of the body attack themselves. Although it is a chronic condition, individuals can have periods with little to no symptoms mixed with acute or symptomatic periods. There can be a genetic component to this disease.
Traumatic arthritis occurs as a result of blunt, penetrating, or repeated trauma to a joint. Damage to the articular cartilage can occur when extreme force or pressure is exerted on a joint, causing the cartilage to tear or break off into small pieces. These pieces can become lodged in the joint, where they will rub against the other joint structures. This trauma can make the joint weak, causing the inflammation and pain associated with arthritis.
- Severe pain and aching in the hip
- Loss of range of motion of the hip
- Swelling around the joint
- Increased size or visible deformity of the joint
- Weakness that makes daily activities, particularly those that require bending at the waist, running or walking difficult
- A sensation of “cracking” or “crunching” in the hip joint
- Stiffness, that can be extreme, causing tremendous difficulty moving the joint
Severe: Individuals with severe joint degeneration have significant pain, stiffness, loss of motion and function. The cartilage on the joint surfaces has been eroded and X-rays reveal a loss of joint space and “bone on bone” contact. Joint replacement is the treatment of choice. At this point quality of life becomes a concern. Following a joint replacement the artificial hip will be different from the natural joint and there will be some limitations of motion and function. However, a patient’s quality of life is usually significantly improved following a total joint replacement. Recovery following hip replacement can take 3-4 months of intensive physical therapy and rehabilitation. Improvements and functional gains can continue to develop for up to a year following the procedure.
Total Hip Replacement
A hip replacement is a surgical procedure. A hip can be resurfaced, or the joint can be completely removed and replaced with artificial material.
Total hip replacement may be indicated in severe cases of osteoarthritis, rheumatoid arthritis or traumatic arthritis. Patients who have intact tendons in the hip joint tend to be good candidates for a total hip replacement. There are several different designs for hip replacements but all have two components: the ball made of highly polished strong metal or ceramic and the socket, a durable cup made of plastic, metal, or ceramic material. Cement may or may not be used to stabilize the prosthesis on the existing bone.
Physical Therapy Interventions
Physical Therapists are professionals, educated and trained to administer interventions. As defined by The Guide to Physical Therapist Practice, interventions are the skilled and purposeful use of physical therapy methods and techniques to produce changes consistent with the diagnosis, prognosis and the patient or client’s goals.
Following joint replacement surgery, a program of physical therapy interventions will be essential to recovering from the procedure and regaining range of motion and proper function of the hip complex. Common Physical Therapy interventions in the treatment of post surgical hip replacement include:
- Manual Therapeutic Technique (MTT): Hands on care including soft tissue massage, stretching and joint mobilization by a physical therapist to improve alignment, mobility and range of motion of the hip. Use of mobilization techniques also help to modulate pain.
- Therapeutic Exercises (TE) including stretching and strengthening exercises to regain range of motion and strengthen muscles of the shoulder and upper extremity to support, stabilize and decrease the stresses place on joint cartilage and hip joint.
- Neuromuscular Reeducation (NMR) to restore stability, retrain the lower extremity, and improve movement techniques and mechanics (for example, running, kneeling, squatting and jumping) of the involved lower extremity to reduce stress on bursa and tendons in daily activities.
- Modalities including the use of ultrasound, electrical stimulation, ice, cold, laser and others to decrease pain and inflammation of the involved joint.
Following surgery, it is important that the patient returns to full activity gradually. Instruction in daily activities and a comprehensive home program are helpful for regaining strength and range of motion in the hip as the surrounding tissues work with the new artificial joint to control the hip. Most patients do well after 3-4 months of intensive physical therapy but can see improvement in pain, gait, strength, and function for up to year following the procedure.