A total hip arthroplasty, commonly known as a hip replacement, is a highly successful procedure that replaces a damaged joint with artificial components, relieving pain and restoring mobility. While the surgery is a significant step toward recovery, the weeks immediately following the operation require strict adherence to specific safety guidelines. These temporary restrictions are necessary to protect the new joint while the surrounding muscles and tissues heal. Following these rules ensures the longevity of the implant and promotes a successful return to daily function.
Understanding the Risk of Dislocation
The primary reason for following post-operative restrictions is to prevent hip dislocation. This complication occurs when the femoral head, or the “ball” of the new joint, comes out of the prosthetic “socket.” The artificial joint is initially unstable because the soft tissues, muscles, and joint capsule that naturally hold the hip in place were manipulated during the procedure.
It takes time for these surrounding structures to tighten and heal, making the hip vulnerable to misalignment. The risk is highest in the first few weeks after the operation. The three major precautions are designed to avoid specific movements that maximize strain and could leverage the new ball out of the socket.
The Three Primary Movements to Avoid
The three primary movements that must be avoided place the highest stress on the healing hip joint. These “don’ts” are most commonly prescribed for patients who have undergone a posterior surgical approach. Avoiding these positions prevents the leverage that could force the new joint out of alignment.
Excessive Hip Flexion
The first restriction is avoiding hip flexion past 90 degrees. This means the angle between your torso and your thigh should not decrease beyond a right angle. Violating this rule often happens when bending over to pick something up or leaning forward excessively while sitting. To maintain the correct angle, patients must avoid sitting in low chairs, using low toilet seats, or lifting the knee of the operated leg higher than the hip level.
Adduction Across the Midline
The second major restriction involves avoiding adduction, which is the movement of the operated leg across the center line of the body. This is often referred to as crossing the legs or ankles while sitting, standing, or lying down. Crossing the legs pulls the hip joint into a position that can destabilize the prosthetic components.
Internal Rotation
The third “don’t” is internal rotation, which involves twisting the operated leg inward so that the toes point toward the opposite leg. This movement is particularly dangerous when the foot is planted on the ground and the body pivots over it, or when twisting the torso while sitting. Internal rotation creates a twisting force that can cause the ball of the joint to shift out of the socket. Patients should consciously keep their toes pointing straight ahead or slightly outward.
Safety Strategies for Recovery
These movement precautions are generally in place for the first six to twelve weeks, which is when most soft tissue healing occurs. The exact duration depends on the surgical approach, the specific implant, and the surgeon’s individual protocol. Patients must adhere to the instructions provided by their surgical team.
Patients can manage the restrictions effectively by utilizing various assistive devices to maintain safety and independence. Tools such as a long-handled reacher allow items to be retrieved from the floor without bending past 90 degrees. A sock aid and dressing stick are helpful for putting on lower body clothing while keeping the hip in a safe position.
Adjusting the environment is another effective strategy for maintaining hip precautions. Using a raised toilet seat or a chair with an elevated cushion ensures the hip remains higher than the knee when sitting, preventing excessive flexion. When sleeping, placing a pillow or wedge between the legs helps prevent the operated leg from inadvertently crossing the midline. When getting in and out of a car, patients should keep the knees together and move the body as a single unit to avoid twisting the trunk.