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FACULTY DISCLOSURE STATEMENT
In accordance with the Accreditation Council for Continuing Medical Education (ACCME) Standards for Commercial Support, educational programs sponsored by Indiana University School of Medicine (IUSM) must demonstrate balance, independence, objectivity, and scientific rigor. All faculty, authors, editors, and planning committee members participating in an IUSM-sponsored activity are required to disclose any relevant financial interest or other relationship with the manufacturer(s) of any commercial product(s) and/or provider(s) of commercial services that are discussed in an educational activity.
COMMITTEE AND AUTHOR DISCLOSURE
Statements of Disclosure of Relevant Financial Relationships have been obtained from R. Michael Meneghini, MD. Dr. Meneghini has disclosed that he has received consulting fees and royalties from Stryker Orthopaedics.
After reading this article, the reader should be able to:
- Discuss the current and projected use of joint revision surgery in the United States.
- Identify the physiologic- and patient-related causes of joint implant failure.
- Describe the key considerations in knee and hip revision surgery.
- Summarize postoperative rehabilitation and expected outcomes following knee or hip revision surgery.
Date of original release: March 2015
Date of expiration: March 2016
Note: While it offers CME credits, this activity is not intended to provide extensive training or certification in the field.
Overview of Joint Replacement and Joint Revision Surgery
Originally conceived as a treatment for joint disease in the elderly, the application of total joint replacement surgery in the United States has increased substantially among both older and younger populations. More than seven million people have had their knees or hips replaced—a total of 4.7 million total knee arthroplasties (TKAs) and 2.5 million total hip arthroplasties (THAs)—which translates to approximately 1.5 percent of Americans currently living with a knee replacement and 0.8 percent with a hip replacement.1 One million new TKAs and THAs are performed every year, and this number is expected to approach four million annually by 2030.2
Over the last four decades, joint replacement surgery has been highly successful in improving quality of life by easing pain, improving range of motion, and increasing activity levels. Today, owing to advances in implant design and surgical technique, knee or hip replacements can function up to 20 years in 90 percent of patients. Yet as seniors live longer and burgeoning numbers of younger persons undergo joint replacement, a steadily enlarging group of patients is outliving their implants and require revision surgery. TKA revisions are projected to increase by 601 percent, from 38,300 in 2005 to 268,200 in 2030, and THA revisions by 137 percent, from 40,800 to 96,700 (Figure 3).
A 65-year-old woman who underwent bilateral TKA 10 years earlier presents with escalating pain in both knees that was never fully relieved with surgery. Pain worsens when she ascends and descends stairs and is greater in the left knee. Physical examination demonstrates tenderness around both knees; increased laxity is noted when the knees are at 90 degrees of flexion. Radiographs demonstrate well-fixed implants (Figure 1A) and a tibial component with increased slope that, when combined with clinical findings, is suggestive of flexion instability (Figure 1B). Screening sedimentation rate and C-reactive protein (CRP) are normal, ruling out infection as a cause of pain.
A 72-year-old man who underwent right THA 18 years earlier presents with persistent right hip pain that is exacerbated by activity. Physical examination reveals pain with hip motion and an antalgic gate. Radiographs show well-fixed implant components and severe polyethylene wear-related peri-acetabular osteolysis (Figure 2). Screening sedimentation rate and CRP are normal, ruling out infection as a cause of pain.
Reasons for Joint Implant Failure
"Implants may fail for several reasons that differ somewhat for TKA and THA" (Table 1), reports R. Michael Meneghini, MD, co-service line leader for IU Health Physicians Orthopedics & Sports Medicine and medical director of IU Health Saxony Hospital Orthopedics & Joint Replacement. "Aseptic loosening, a common cause of knee and hip implant failure, can result from inadequate initial fixation, mechanical loss of fixation over time, or biologic loss of fixation caused by particle-induced periprosthetic osteolysis. Loosening of a knee or hip implant is associated with pain, deformity, dislocation, and instability.
"Infection, which occurs at a rate of about 0.7 percent for TKA and 1.0 percent for THA,3 is another important cause of implant failure," Dr. Meneghini continues. "Prosthetic joint infections developing within the first three months after implantation are thought to be caused by organisms introduced at the time of surgery, whereas late infections are likely hematogenously acquired. Infection may present as new or worsening joint pain, often accompanied by swelling and stiffness."
Fracture of a bone near the implant and/or of a prosthetic component are other causes of implant failure. Additionally, patient-related factors can contribute to the need for revision surgery. Younger, more active patients have higher revisions rates, obese patients are more likely to experience implant wear and loosening, and patients who have undergone previous knee or hip surgery (unrelated to joint replacement) may be at higher risk for implant-related infection.
Knee and Hip Revision Surgery
"Revision joint surgery is complex and challenging, taking two to four times longer to perform than primary arthroplasty and requiring a higher level of expertise by the surgeon and surgical team," Dr. Meneghini emphasizes. "Common to all joint revision operations is an assessment of existing bone quality, removal of the failed implant components, reconstruction of remaining bone and soft tissue structures, and successful fixation of new implant components to bone."
Knee revision surgery
Knee revision surgery requires consideration of the femur, tibia, and patella components. Bone stock deficiencies caused by lysis, fracture, or stress shielding (removal of normal stress to a bone by an implant) are classified according to several grading systems, and the failed components are removed by a combination of surgical methods and specialized instrumentation. Reconstruction may require the use of implants with extensions to reach better quality bone and effectively replace lost ligament stability. Ground up or bulk bone graft (allograft or autograft) may be used when significant bone has been lost.
"Although we frequently use cementless implants for primary TKA, revision knee implants are typically cemented in place, owing to the loss of viable bone, poor bone quality, and mechanics," says Dr. Meneghini.
The patient is scheduled for revision left knee replacement. At the time of surgery, osteolysis resulting from polyethylene bearing wear is encountered in the posteromedial femoral condyle (Figure 4) and remedied with cementation reinforced with a threaded screw for support. During her hospital stay, she is managed by a perioperative medical specialist and undergoes physical therapy (PT). She is discharged home on the second postoperative day to continue her recovery with the assistance of her family. A physical therapist comes to the home thrice-weekly.
Hip revision surgery
In hip revision surgery, both the femoral and acetabular components must be addressed. If some parts of the implant are still functioning, effort is made to retain them. Specialized removal techniques and tools have been developed, including surgically splitting the femur to remove the implant and cement, and power and hand instruments to accurately cut around the prosthesis.
"Revision hip implants are usually porous-coated (cementless) to allow bone ingrowth," Dr. Meneghini explains. "In the revision setting, biologic fixation is needed, and cemented implants do notwork as well."
The patient elects to undergo a revision hip replacement to remove the worn polyethylene and replace the acetabular component. At the time of surgery, radiographic evidence of osteolysis is confirmed by the presence of a severe superior acetabular bone defect (Figure 5A). The defect is filled with morselized allograft bone (Figure 5B). The patient is discharged home on the second postoperative day. Weight-bearing is restricted and PT postponed for six weeks to minimize stress on the implant-bone interface and facilitate bone ingrowth and osseointegration.
Postoperative Care and Rehabilitation
Postoperative care after knee or hip revision surgery is similar to that required for primary joint replacement and includes blood and pain management, thromboprophylaxis, and antibiotic therapy. Length of hospital stay is typically longer for revision surgery, likely attributable to age-related comorbidities, the complexity of the surgical procedures, and rehabilitation issues.4
In patients undergoing revision TKA, rehabilitation and PT are generally initiated within 24 hours of surgery and continue for one month (PT is not typically a component of care post-THA revision). Initially, partial weight-bearing or toe-touch weight-bearing may be necessary to promote bone healing, particularly for revision THA patients. Assistive devices, such as walkers, crutches, and even wheelchairs, are used early in the convalescence period, with the patient progressing to a cane or walking without assistance as he or she recovers. Gains in strength and mobility may continue for one to two years after surgery.
Postoperative care after knee or hip revision surgery is similar to that required for primary joint replacement and includes blood and pain management, thromboprophylaxis, and antibiotic therapy.
"Joint revision surgery benefits most patients reporting an onset of pain after total knee or hip replacement that is attributable to a clear-cut problem (e.g., implant loosening, infection)," Dr. Meneghini concludes. "Despite the higher rate of complications associated with revision versus primary joint replacement, more than 90 percent of patients who undergo revision knee or hip surgery have good to excellent outcomes, experiencing pain relief and improved mobility. Moreover, revision knee and hip patients report a much higher rate of satisfaction with their surgeries, as assessed by Hospital Consumer Assessment of Healthcare Providers and Systems (H-CAHPS) scores, than do those undergoing primary joint replacement. This heightened satisfaction likely reflects appreciation for having the severe pain associated with a failed implant adequately addressed to improve their quality of life."
The patient obtains substantial pain relief from the revision left TKA and subsequently undergoes revision of the right knee. At one-year follow-up, she reports being pain-free and experiencing dramatic improvements in joint function and quality of life (Figure 6).
At one-year follow-up, the patient is pain-free. Radiographs demonstrate some early consolidation of allograft bone superior to the new acetabular component (Figure 7).
"Revision knee and hip patients report a much higher rate of satisfaction with their surgeries, as assessed by Hospital Consumer Assessment of Healthcare Providers and Systems (H-CAHPS) scores, than do those undergoing primary joint replacement."
Dr. Meneghini is a graduate of the IU School of Medicine, received his residency training in orthopedic surgery at Rush University Medical Center in Chicago, and completed a fellowship in adult hip and knee reconstruction at the Mayo Clinic in Rochester, MN. His areas of specialty include primary and complex revision hip and knee replacement, unicompartmental (partial) knee replacement, minimally invasive surgery, and computer and robotic-assisted surgery. He has special interests in clinical and biomechanical orthopedic research and collaborates with the Los Alamos National Laboratory to investigate novel methods of improving hip replacement surgery via vibration analysis methods.
Dr. Meneghini is a diplomate of the American Board of Orthopaedic Surgery, a member of the prestigious Knee Society and Hip Society, and an adjunct professor of mechanical and biomechanical engineering at Rose-Hulman Institute of Technology in Terre Haute. The author of more than 55 peer-reviewed journal articles and numerous book chapters on hip and knee replacement, Dr. Meneghini was recognized by Orthopedics This Week as one of the top 22 knee surgeons in North America in 2014.
Maradit-Kremers H, Crowson CS, Larson D, Jiranek WA, Berry DJ. Prevalence of total hip (THA) and total knee (TKA) athroplasty in the United States. Poster 057, presented at the American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014; New Orleans, LA.
Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007;89(4):780-785.
Moran E, Byren I, Atkins BL. The diagnosis and management of prosthetic joint infections. J Antimicrob Chemother. 2010;65 Suppl 3:iii45-54.
Bozic KJ, Kamath AF, Ong K, et al. Comparative Epidemiology of Revision Arthroplasty: Failed THA Poses Greater Clinical and Economic Burdens Than Failed TKA. Clin Orthop Relat Res. 2014.