Case 1: Permanent Temporary Spacer
A 76-year-old man presented to the emergency room with fever and a 2-week history of worsening left hip pain followed by an acute dislocation. The patient had undergone total hip arthroplasty (THA) 12 years earlier. The left hip functioned well until 1 year ago, at which time he began to experience recurrent dislocation caused by polyethylene wear. He had two THA dislocations during the previous 6 weeks, and both were successfully treated by closed reduction.
The patient was found to be febrile with a leukocytosis and large left hip fluid collection on presentation to the emergency department. The patient’s blood cultures and left hip aspirate contained methicillin-sensitive Staphylococcus aureus (MSSA). He also had progressive Alzheimer disease and prostate cancer. He currently lives in a skilled nursing facility.
Examination and laboratory tests confirmed a diagnosis of hematogenous MSSA infection of a recurrently unstable THA ( Figs. 75.1 and 75.2 ). Based on the severity (i.e., bacteremia and leukocytosis) and chronicity (i.e., 2-week history of worsening pain) of the infection, along with the hip instability, I proceeded with aggressive débridement and resection arthroplasty on a semi-urgent basis. Resection of the well-fixed femoral stem required the use of an extended trochanteric osteotomy. The acetabular component was removed with the Explant Acetabular Removal System (Zimmer, Warsaw, Ind.). A long prosthesis with high-dose antibiotic-impregnated acrylic cement (PROSTALAC, DePuy, Warsaw, Ind.) was used to reconstruct the hip and bypass the osteotomy. Vancomycin (4 g/batch of cement) and tobramycin (4.8 g/batch of cement) were used in the PROSTALAC. The osteotomy was secured with solid wire. Braided suture and cable were intentionally avoided.
The patient was treated with 6 weeks of parenteral antibiotics, during which time weight bearing was limited to 50 pounds to protect the osteotomy site ( Fig. 75.3 ). Two weeks after the discontinuation of antibiotic therapy, C-reactive protein and erythrocyte sedimentation rate values were obtained. Both laboratory values remained elevated. A hip aspiration was performed under fluoroscopy, and culture of the aspirate produced negative results with a nucleated cell count of 1654 cells/μL.
The risks of PROSTALAC exchange compared with reimplantation were discussed with the patient and family, and due to the limited functional demand and underlying dementia, they decided to retain the PROSTALAC. The PROSTALAC remained in place without signs of recurrent infection or failure at the final follow-up evaluation 13 months postoperatively.
Case 2: Early Single-Stage Revision
A 65-year-old man presented to the office with prolonged wound drainage 18 days after routine THA for degenerative arthritis. After an uneventful postoperative course, the patient was discharged from the hospital with a dry wound on postoperative day 3 to a subacute rehabilitation facility. Nursing documentation revealed that the patient developed a serous drainage on postoperative day 10 that has persisted. The patient was afebrile and had well-controlled pain. The wound appeared to be clean, with minimal erythema but moderate serous drainage. No antibiotics had been given. The patient also had hypertension and hypercholesterolemia. He currently lives independently, works as a volunteer at the fire department, and is a community ambulator.
Diagnosis required differentiation of prolonged postoperative wound drainage from early postoperative infection ( Fig.75.4 ). The patient was readmitted to the hospital. Antibiotics were withheld, and he underwent fluoroscopically guided hip aspiration. The hip aspirate demonstrated 31,025 nucleated cells/μL with a differential that included 92% polymorphonuclear cells (PMNs). A diagnosis of acute periprosthetic infection was based on these values.
A single-stage revision was performed. The uncemented implants were removed, which improved the ability to débride the femoral canal and acetabulum. Aggressive débridement and irrigation were performed with antibiotic solution. A new surgical field was established. The hip was reconstructed with similar, uncemented implants due to the patient’s age and activity level and acute nature of the infection. Intraoperative cultures and preoperative hip aspirate confirmed infection with a methicillin-sensitive, group C β-hemolytic Streptococcus . The patient was treated with 6 weeks of parenteral antibiotics, followed by 6 months of oral therapy, and he remains infection free at 3 years after surgery.
Infection after THA remains a difficult problem for the patient and surgeon. Although improved surgical techniques and perioperative care have decreased the rate of deep prosthetic infection, it still complicates a small percentage of cases. In a review of 124,759 primary THAs from the Norwegian Arthroplasty Register, Engesaeter and colleagues found an infection rate requiring revision surgery of 0.7%. As the cause of 14.8% of revision THAs, periprosthetic infection is the third leading cause for revision. With an exponential rise in the annual number of total joint arthroplasties (TJAs), even with a low infection rate, deep periprosthetic infection will continue to be a common cause of painful and failed TJAs.
Periprosthetic infection is commonly managed by débridement with retention of components, although retention of components in the face of active infection remains a concern. Numerous studies have demonstrated high failure rates and a narrow window for successful intervention. The Mayo Clinic reported a 60% 2-year survival rate for ninety-nine patients treated with retention of components despite 89% of patients remaining on oral antibiotics for suppression of infection. Risk factors for failure in this series included a sinus tract and duration of symptoms of more than 7 days, with associated 2-year success rates of 39% and 49%, respectively. Only 12.5% of patients with a Staphylococcus aureus infection were successfully treated with retained components in this series. A similar series found that the window of opportunity for successful débridement with retention of components in the setting of an S. aureus infection was only 2 days, with a relative risk of 4.2 for failure with further delay.
The gold standard for treatment of an infected TJA is a two-stage revision. During the first stage, resection of the infected prosthesis and soft tissue débridement are performed, followed by placement of an antibiotic-impregnated cement spacer. The second stage, usually performed 8 to 12 weeks later, includes repeat débridement and reimplantation after eradication of the infection. The successful eradication of infection with two-stage revision averages 80% to 93%. However, success rates in cases with resistant bacteria have been as low as 47%. After a failed two-stage procedure, patients with a resistant organism undergoing another procedure have a success rate of about 25%. Although earlier studies of two-stage revisions focused on short-term cure rates, a later study looking at midterm to long-term follow-up of staged hip reimplantation raised additional concerns. The 10-year prosthetic survival rates free of infection or mechanical failure were 87.5% and 75.2%, respectively, after two-stage revision in 169 hips at the Mayo Clinic.
Despite being the preferred procedure, two-stage revision is associated with a significant failure rate, significant patient morbidity, and exorbitant costs. Two-stage revision is far from ideal for the patient, surgeon, hospital, and health care system, and for a selected group of patients, single-stage revision may be the best option. A literature review by Jackson and Schmalzried demonstrated an 83% success rate for eradication of infection with a direct exchange in 1077 infected THAs. This rate is comparable to acceptable rates for a two-stage revision. The Norwegian Arthroplasty Register demonstrated an 88% 2-year Kaplan-Meier survivorship for a single-stage exchange compared with a 92% survivorship for two-stage revision.
Although most studies focus on eradication of infection as the sole outcome measure, Wolf and co-workers looked at quality-adjusted life years in their review comparing single-stage and two-stage revisions. They found one-stage revision to be superior in terms of short-term and long-term outcome models using patient- and surgeon-derived outcomes. Klouche and associates performed a cost analysis and determined that two-stage revision had a 1.7-fold increase in cost compared with single-stage revision for infection. This raises the question of how much cost a patient and the health care system should endure to improve success rates by as little as 4%.
Single-stage revision currently has a limited role at my institution. This chapter reviews the preoperative evaluation, intraoperative techniques, and postoperative care for single-stage revision as the treatment of a selected group of patients with an infected THA.
Indications and Contraindications
Relative indications include acute perioperative infection with uncemented components, acute hematogenous infection with a low-virulence organism (i.e., methicillin-sensitive Staphylococcus epidermidis , S. aureus , and Streptococcus sp), and a healthy patient with good-quality soft tissues and minimal bone loss.
Contraindications include chronic periprosthetic infection with compromised soft tissues, chronic periprosthetic infection with a sinus tract, chronic periprosthetic infection with a methicillin-resistant organism (i.e., methicillin-resistant S. epidermidis and group D streptococci), polymicrobial infections, and gram-negative infections (e.g., Pseudomonas ).