Total hip arthroplasty, commonly known as hip replacement, is a highly successful procedure for relieving pain and restoring mobility in patients with severe hip arthritis. The posterior approach is a traditional and widely used surgical technique, accessing the hip joint through the back of the thigh and buttock. While this approach provides excellent visibility for the surgeon to precisely place the new artificial joint components, it is associated with specific post-operative challenges and drawbacks. These disadvantages are primarily related to the necessary manipulation of surrounding soft tissues and anatomical structures near the surgical path. The discussion focuses on the distinct limitations that make the posterior approach a more demanding recovery compared to newer, muscle-sparing methods.
Increased Risk of Post-Surgical Dislocation
The most commonly cited disadvantage of the posterior approach is the heightened risk of the new hip joint dislocating, which is when the femoral ball component pops out of the acetabular socket. This risk is primarily a consequence of the surgical technique, which requires the detachment of the posterior capsule and the small, deep external rotator muscles of the hip to access the joint. These structures normally act as natural stabilizers, preventing the ball from moving backward out of the socket.
Even though surgeons carefully repair and reattach these tissues at the end of the procedure, the initial healing phase leaves the joint temporarily vulnerable. The risk of dislocation is highest during the first six to twelve weeks following surgery while the soft tissues are mending. Specific movements that combine hip flexion (bending the hip past 90 degrees), adduction (crossing the leg over the body’s midline), and internal rotation greatly increase the likelihood of this complication. The risk remains comparatively higher than with approaches that do not require the cutting of these posterior stabilizers.
Impact on Local Musculature and Recovery
To perform the posterior approach, the surgeon must navigate through and manipulate several muscle groups to reach the hip joint. The large gluteus maximus muscle is split in line with its fibers, and the short external rotator muscles—including the piriformis, gemelli, and obturator muscles—must be cut from their attachment points on the femur. These small muscles are essential for hip stability and power, and their necessary detachment causes trauma to the surrounding soft tissue.
This required muscle disruption generally leads to a greater amount of initial post-operative pain compared to techniques that spare these structures. The cutting and reattaching of these rotators can also result in a longer initial rehabilitation phase as the patient must wait for the muscles and tendons to heal sufficiently. Patients may experience a temporary reduction in hip power and stability immediately following the procedure, which can slow down the ability to walk normally and confidently in the first few weeks of recovery.
Potential for Sciatic Nerve Irritation or Injury
The sciatic nerve, the body’s longest and widest nerve, runs in close anatomical proximity to the posterior surgical field. Specifically, the nerve lies directly beneath the short external rotator muscles that are manipulated or cut during the approach. This close relationship makes the sciatic nerve susceptible to irritation or injury during the procedure due to direct trauma, excessive retraction, or tension.
While a rare complication, the injury can manifest as temporary irritation, known as neuropraxia, causing tingling, numbness, or weakness in the leg or foot. A more serious consequence is damage that results in a foot drop, where the patient cannot lift the front part of the foot. The proximity of the nerve to the surgical site introduces an inherent risk that is a specific concern for the posterior approach.
Strict and Prolonged Post-Operative Restrictions
The inherent risk of dislocation associated with the posterior approach necessitates the imposition of strict post-operative movement limitations, often referred to as “hip precautions.” These precautions are designed to prevent the vulnerable movements that could cause the ball to dislodge from the socket. Patients must strictly avoid bending the hip more than 90 degrees, which affects sitting, dressing, and picking up objects from the floor.
Furthermore, patients are instructed not to cross their legs or ankles and to avoid turning the operated leg severely inward (internal rotation) for a designated period. These restrictions are typically enforced for six to twelve weeks, sometimes longer, depending on the surgeon and patient factors. This extended period of restricted movement significantly impacts patient independence, requiring the use of assistive devices like reachers and elevated toilet seats during the recovery period.