Knee replacement surgery is a common procedure to alleviate severe knee pain and improve mobility. It involves replacing damaged knee joint parts, often due to osteoarthritis, with artificial components. While the primary goal is to restore knee function, patients often wonder how this change influences other joints, particularly the hip.
The Interconnected Lower Body
The human body functions as a complex system where various parts are mechanically linked, forming a kinetic chain. This lower body chain includes the pelvis, hips, thighs, knees, lower legs, ankles, and feet. These joints and their surrounding muscles work in concert to facilitate movement and maintain stability during daily activities. The knee acts as a crucial link between the hip and ankle; any change in its function can ripple through the lower limb. Coordinated muscle activation and proper alignment are necessary for efficient motion, explaining how knee replacement can alter adjacent joint mechanics.
How Knee Replacement Influences Hip Mechanics
After knee replacement surgery, a person’s walking and movement patterns can change substantially. Patients may adjust their gait to accommodate the new joint, which can stress the hip. These altered biomechanics often develop as a continuation of movement patterns established before surgery to avoid knee pain. If continued, these compensatory movements can lead to discomfort or pain in other areas, including the hip.
Changes in limb alignment also influence hip mechanics. A leg length discrepancy can occur after knee replacement, where the operated leg may feel slightly longer. Even a minor difference can cause a person to limp, distributing weight unevenly and straining the hip, lower back, or ankle. Patients may also rely more on their hip and ankle joints to compensate for reduced movement or strength at the knee.
Muscle activation patterns around the hip can also be affected. Weakness in the hip muscles, particularly the glutes, can develop due to reduced activity before and immediately after surgery or from altered movement patterns. These muscles are important for stabilizing the pelvis and supporting the body. If the gluteal muscles are not adequately strong, other muscles, such as those in the thigh, may become overused, leading to increased pressure on the knee and issues in the hip.
Addressing Hip Discomfort After Surgery
Addressing hip discomfort after knee replacement surgery primarily involves comprehensive post-operative rehabilitation. Physical therapy plays a central role, helping individuals regain full range of motion, improve muscle strength, and restore functional mobility. Therapists work to identify and correct any changes in walking patterns or muscle imbalances contributing to hip pain.
Exercises strengthening the muscles around the hip are a common component of rehabilitation. These may include straight leg raises, side-lying leg raises to target hip abductors, and glute sets. Squats and other multi-joint movements can also help build overall lower body strength and coordination. Such exercises help ensure the hip muscles can support the body and alleviate stress on the joint.
Gait training is also important to normalize walking patterns and address any lingering compensatory habits. Physical therapists guide patients to adjust their stride and weight distribution, preventing uneven loading that could affect the hip. If hip pain persists, a medical assessment can help rule out other causes, such as pre-existing hip arthritis or nerve irritation from the surgery itself. If a leg length discrepancy is suspected, an X-ray can confirm the difference, and shoe insoles can provide a solution.