Mechanisms of Failure: Indications for Revision Total Hip Arthroplasty

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• A thorough history, physical examination, laboratory investigations, and imaging studies must be performed. All data are properly analyzed to identify the cause of a failed total hip arthroplasty.

• Infection should always be considered in the differential diagnosis.

• Revision surgery should be goal oriented and meticulously planned.

• The surgeon should be prepared for the worst-case scenario.

• When in doubt, cases are referred to a subspecialist.

Introduction

Primary total hip arthroplasty (THA) is one of the most successful procedures in modern medicine, with a clinical success rate exceeding 90% at 10 years. However, early and delayed failures are recurring problems that often require revision procedures.

With an aging population, the demand for primary total joint arthroplasty has increased, and the number of revision hip procedures is expected to increase to 96,700 by 2030 (137% increase compared with 2005). The growing elderly population and broadening of indications, including performing total joint arthroplasties in younger, active patients, will contribute to this increased volume of revisions.

Some authorities have tried to estimate the rate of change. Looking at a 12-year follow-up period, Katz and colleagues projected that the rate of revision THA in the Medicare population would increase by 2% per year in the first 18 months and then 1% per year thereafter. Revision surgery of any kind is often associated with prolonged operative time, additional blood loss, and higher rates of infection, thromboembolism, dislocation, and nerve palsy. Postoperative complications after revision surgery are increasingly prevalent, especially in the elderly population. Given the need to reduce costs and improve value in the current health care system, it is imperative that the indications for revision surgery be well defined and goal oriented.

Because the array of challenges associated with revision THA exceed those of primary THA, preoperative assessment and planning are crucial. This process should include a comprehensive patient history, physical examination, imaging, laboratory tests, and a review of systems to identify medical comorbidities that may influence the treatment plan. Preoperative planning should include a meticulous review of high-quality radiographs, other imaging studies, and templating. This systematic approach enables the formulation of many goal-oriented plans and leads to optimal selection of the implants, instruments, equipment, bone graft, and personnel needed to ensure that the procedure is executed as effectively and efficiently as possible.

In evaluating the need for revision THA, the correct failure mode must be elucidated to provide successful treatment. Knowledge of certain patient comorbidities, such as diabetes, obesity, and rheumatoid arthritis, can direct the surgeon to the likely failure mechanism and assist with risk stratification. Referred sources of pain (e.g., lumbar stenosis) must be ruled out. The surgeon must decide whether the level of disabling pain is sufficient to warrant a major operation. Alternatives to revision THA, especially for elderly patients who are typically less physically active and may have lower demands and expectations, may include activity modification, weight loss, use of external support, and pain management through pharmacologic interventions.

Pain is the most common symptom of patients presenting with a failed primary THA. Pain around the hip and pelvis can be divided into extrinsic and intrinsic causes. Pain extrinsic to the hip joint may be caused by lumbar spinal disease, arterial insufficiency, malignancy, iliotibial band syndrome, or hernia. Intrinsic causes of hip pain include sepsis, aseptic loosening, modulus mismatch, periprosthetic fracture, instability, bursitis, iliopsoas snapping or tendinitis, and adverse local tissue reaction.

A systematic characterization of the pain, including onset, location, radiation, exacerbating factors, and severity, can help the surgeon to identify potential causes. Pain that has persisted since the initial operation may be caused by infection, failure of osseointegration of cementless implants, periprosthetic fracture, or an incorrect initial diagnosis. Discomfort that begins after an initial pain-free period may result from aseptic loosening, fracture, iliopsoas irritation, instability, acute hematogenous infection, or chronic infection. Pain localized to the groin often correlates with intrinsic hip pathology, whereas lateral pain occurs with trochanteric bursitis or pathology intrinsic to the abductor mechanism. Pain that is posterior in the buttock region or radiates down past the knee may have a lumbar origin, whereas pain that occurs at night or while resting can be attributed to infection or neoplasm. Pain due to socket pathology typically hurts in the groin, buttocks, or “deep inside,” whereas localized, nonradiating thigh pain is often attributable to femoral stem pathology.

Failure of the primary THA may have a variety of causes. The most common causes of failure and indications for revision procedures in the United States Medicare population as of 2006 included instability and dislocation (22.5%), mechanical loosening (19.7%), periprosthetic infection (14.8%), osteolysis or aseptic loosening (8%), periprosthetic fractures, and adverse local tissue reaction associated with metal-on-metal bearings.

Indications for Revision Surgery