Total hip replacement (THR) is a highly successful procedure, offering significant pain relief and improved mobility for millions of people. While modern implants are durable, they are not designed to last forever, with an average lifespan of about 15 to 20 years before potential failure. Hip revision surgery, also known as revision total hip arthroplasty, is the specialized procedure required when the original artificial joint begins to wear out or develops complications. This corrective operation involves removing some or all of the failed components and replacing them with new ones to restore function and alleviate discomfort.
Understanding Hip Revision Surgery
Hip revision surgery is different from the initial total hip replacement, presenting a more complex challenge for the surgical team. The overall goal remains the same—to relieve pain and improve hip function—but the technical demands are higher due to the presence of the original implants and surrounding scar tissue. This procedure requires extensive pre-operative planning and the use of specialized tools and implants designed for revision cases.
The scope of the operation can vary widely, ranging from a partial revision to a complete exchange of all prosthetic parts. A partial revision might involve only changing the polyethylene liner and the femoral head, a relatively minor procedure if the main components remain stable. A full revision requires replacing the acetabular cup, the femoral stem, and all associated parts, which is a much more involved and time-consuming operation. Most primary hip replacements show excellent long-term success, with only about 5% of patients requiring a revision within 10 years and approximately 15% needing one within 20 years.
Common Reasons for Revision
The need for a revision surgery arises from several mechanisms of failure, categorized by the time elapsed since the original procedure. Early failures, often occurring within the first few years, are related to instability or infection. Later failures are commonly associated with mechanical wear and loosening of the components over time.
One of the most frequent indications for late revision is aseptic loosening, the mechanical failure of the implant to remain securely fixed to the bone without infection. This occurs when microscopic wear particles from the bearing surfaces trigger a biological response that leads to the destruction of the surrounding bone, a process called osteolysis. As the bone around the implant degrades, the component loses its stable integration and begins to move, causing pain and instability.
Component wear is closely linked to aseptic loosening, as the breakdown of the bearing surface material, particularly the polyethylene liner, generates the debris that initiates the osteolysis. Recurrent instability, or dislocation, is another common reason for revision, occurring when the ball component repeatedly slips out of the socket. This can be due to component malposition from the initial surgery, failure of the surrounding soft tissues, or excessive wear causing the joint to become unstable.
Periprosthetic joint infection (PJI) represents a serious cause for revision, accounting for a significant portion of early failures. Bacteria colonize the surface of the artificial joint, forming a biofilm resistant to treatment. Treating PJI often requires a two-stage surgery: the infected implants are removed, an antibiotic-loaded cement spacer is placed, and a new prosthesis is implanted months later once the infection is eradicated.
The Surgical Procedure
The surgical process for a hip revision is more challenging than the initial hip replacement because the surgeon must navigate existing scar tissue and remove implants that may be firmly integrated into the bone. The procedure begins with meticulous pre-operative planning, involving advanced imaging and templating to anticipate bone loss and select specialized revision implants. Planning is important to determine the size and type of the new components, which are often longer or bulkier than primary implants to compensate for lost bone stock.
The most technically demanding step is the removal of the old components, especially if the femoral stem is well-fixed with cement or bone ingrowth. Specialized tools are used to carefully separate the implant from the bone, often requiring controlled cuts or windows to minimize damage. The surgeon must preserve as much of the patient’s existing bone as possible, as this remaining healthy bone, known as bone stock, directly impacts the success and longevity of the new prosthesis.
After the old parts are removed, the surrounding bone is prepared for the new implants, which frequently involves addressing areas of significant bone loss. This loss may be managed using structural bone grafts or metal augments that fill in the defects. Revision stems are often longer to bypass weakened bone segments and achieve stable fixation lower down in the femur. The entire operation typically takes several hours, which is longer than a primary hip replacement, and requires high surgical expertise.
Recovery and Rehabilitation Timeline
Recovery from hip revision surgery is more protracted compared to the initial hip replacement due to the complexity of the operation and increased tissue trauma. Patients typically spend two to four days in the hospital for pain management and early mobilization. Pain control is managed through a combination of medications during the early post-operative period.
Physical therapy begins almost immediately, often on the first day after surgery, focusing on gentle range-of-motion exercises and supervised ambulation with an assistive device. The initial recovery phase, lasting about six weeks, involves strict adherence to weight-bearing restrictions, which are often more conservative than after a primary hip replacement, especially if significant bone grafting was required. Full recovery can take six to twelve months, depending on the extent of the revision and the patient’s overall health.
Patients must commit to a dedicated rehabilitation program to regain strength and mobility, as the soft tissues and muscles around the hip have been more extensively manipulated. Long-term prognosis is positive, with the goal of achieving a pain-free, functional joint, although the revised implant may not have the same anticipated lifespan as the original primary hip replacement. Continuous follow-up with the surgeon is necessary to monitor the stability and wear of the new components.