B. J. Waldman

Multiple irrigation, debridement, and retention of components in infected total knee arthroplasty

The results of 24 infected total knee arthroplasties (22 patients) that were treated by irrigation, debridement, and retention of the prosthetic components were prospectively studied. Strict criteria were used for the selection of this method of treatment. Patients had to be less than 30 days after index arthroplasty (postsurgical group) or had to have less than 30 days of knee symptoms (hematogenous group). In addition, there had to be no radiographic signs of osteitis or evidence of a loose prosthetic component. Patients had one to three irrigation and debridement procedures depending on systemic signs, knee symptoms, or the results of knee aspirations. All of the immediate postsurgical infections (10 knees) and 10 of the 14 (71%) late hematogenously infected knees retained the prosthesis without further evidence of infection at the final follow-up visit at 48 months (range, 24-140 months). This study shows that in selected circumstances, irrigation, debridement, and retention of the components can result in low morbidity with high success rates.

Evaluation of preoperative cultures before second-stage reimplantation of a total knee prosthesis complicated by infection: A comparison-group study

Background: Two-stage reimplantation has proven to be highly successful in the treatment of patients with infection at the site of a total knee arthroplasty. However, up to 20 percent of patients have a recurrence of infection following this treatment. The purpose of our study was to determine whether aspiration of the affected joint and culture of the specimen, performed before reimplantation and after discontinuation of antibiotic therapy, would help to identify patients who might have a recurrent infection.Methods: We prospectively followed sixty-nine patients who were treated for a culture-proven deep infection at the site of a total knee arthroplasty. Group I consisted of thirty-five patients who were treated with removal of the prosthetic components and irrigation and débridement of the joint, followed by six weeks of antibiotic therapy and reimplantation of a prosthesis. Group II was composed of thirty-four patients who were treated with removal of the components and irrigation and débridement of the joint, six weeks of antibiotic therapy, and then repeat culture four weeks after the antibiotic course had ended. If the culture was negative, the patient was managed with a second-stage reimplantation of a prosthesis. If the culture was positive, the protocol was repeated, beginning with irrigation and débridement. The two groups were similar with regard to male-to-female ratio, age, preoperative Knee Society scores, time since primary surgery, types of infectious organisms, duration of symptoms, duration of follow-up, and number of previous revisions. All of the patients were evaluated clinically with use of the objective scoring system of the Knee Society and were followed with serial radiographs. Success was defined as no infection and a functional prosthesis, with a Knee Society score of at least 75 points at the last (thirty-six-month-minimum) follow-up evaluation.Results: Of the thirty-five patients in Group I, five (14 percent) had recurrence of infection. One of the patients was managed with a successful second-stage revision, three were managed with arthrodesis of the knee, and one continued dwith chronic antibiotic suppressive treatment. Of the thirty-four patients in Group II, three (9 percent) had a positive culture after the course of antibiotics. The protocol was repeated for all three, and they subsequently had a successful second revision. One other patient (3 percent) in Group II, who had a negative culture, had a recurrent infection and was eventually managed with arthrodesis of the knee.Conclusions: Prerevision cultures, grown after discontinuation of antibiotic treatment and before reimplantation of the components, helped to identify the patients with infection at the site of a total knee arthroplasty in whom the infection might recur. The performance of aspiration and cultures resulted in a substantial improvement in the clinical outcome.

Infections associated with dental procedures in total hip arthroplasty

Dental procedures may lead to a transient bacteraemia lasting for up to 30 minutes. Of the numerous cases of total hip arthroplasty (THA) reported which have been infected from haematogenous sources, dental procedures have been involved only infrequently. We reviewed the records of 2973 patients after THA. Of the late infections identified in 52 patients, three (6%) were strongly associated with a dental procedure. Infection was diagnosed by culture from the affected joint; Streptococcus viridans was identified in two cases and Peptostreptococcus in one. One patient had diabetes mellitus and another rheumatoid arthritis, both conditions predisposing to infection. The dental operations all lasted for more than 45 minutes and no patient received perioperative antibiotics. Infection of a THA after dental procedures is more common than has been previously suspected. Patients with systemic disease, or who are undergoing extensive procedures, should be considered for prophylactic antibiotic treatment.

Total knee arthroplasty infections associated with dental procedures

Total knee arthroplasties are at risk for hematogenous seeding secondary to procedures that create a transient bacteremia. To define the risk of infection associated with dental surgery, a retrospective review of the records of 3490 patients treated with total knee arthroplasty by the authors between 1982 and 1993 was performed. Sixty-two total knee arthroplasties with late infections (greater than 6 months after their procedure) were identified, and of these, seven infections were associated strongly with a dental procedure temporally and bacteriologically. These seven cases represented 11% of the identified infections or 0.2% of the total knee arthroplasty procedures performed during this period. In addition, among 12 patients referred for infected total knee arthroplasties from outside institutions, two infections were associated with a dental procedure. Five of the nine (56%) patients had systemic risk factors that predisposed them to infection, including diabetes and rheumatoid arthritis. All dental procedures were extensive in nature (average, 115 minutes; range, 75-205 minutes). Eight of the patients received no antibiotic prophylaxis. One patient had only one preoperative dose. Infections associated with dental procedures may be more common than previously suspected. Eight of these patients had no prophylactic antibiotics, and one had inadequate coverage. The authors think that patients with a total knee arthroplasty who have systemic disease that compromises host defense mechanisms against infections and who undergo extensive dental procedures should receive prophylactic antibiotics. A first generation cephalosporin, given 1 hour preoperatively and 8 hours postoperatively would provide the best prophylaxis against the organisms identified in this study.

Ankle Fractures: The Lauge-hansen Classification Revisited

Rational treatment of ankle fractures requires knowledge of the extent of bone and soft tissue injury. Although the Lauge-Hansen classification attempts to do this by relating specific fracture patterns to injury mechanism, the experimental underpinning for this classification has not been reexamined rigorously using modern experimental methods. This study examines the hypothesis that the clinically occurring supination and external rotation injury pattern does not result from the mechanism described by Lauge-Hansen. Thirty-two ana-tomic specimen ankles were mounted on an MTS machine for combined axial loading with external rotation to failure testing. A foot plate supinated the foot 25°. Testing was performed with the ankle at neutral, 25° plantar flexed, 10° to 15° dorsiflexed, and in 6° to 8° leg valgus. Pure supination and external rotation with the ankle in neutral did not result in the Lauge-Hansen supination and external rotation type fractures. This outcome was not altered if the ankle specimens initially were placed in plantar flexion or dorsiflexion. The addition of a valgus load, which pushes the talus laterally against the fibula, resulted in the classic Lauge-Hansen supination and external rotation type fracture. All specimens had an isolated lateral injury or a lateral injury that preceded medial injury.

Use of a Functional Temporary Prosthesis in a Two-Stage Approach to Infection at the Site of a Total Hip Arthroplasty

Two-stage revision arthroplasty is the gold standard for treatment of infection at the site of a total hip arthroplasty1-9. Unfortunately, removal of the components followed by a delay for antibiotic treatment can result in prolonged morbidity5,6. We describe two novel approaches to two-stage revision arthroplasty. ### General Description (Figs. 1-A, 2, 3) In thirty-two consecutive patients with an infection at the site of a total hip arthroplasty, we utilized a spacer composed of either the removed femoral component, which was autoclaved and then reimplanted, or an inexpensive modular femoral component. The femoral implant is coated with a mantle of antibiotic-impregnated polymethylmethacrylate before reinsertion3,7. A polyethylene acetabular liner is cemented in place with the same antibiotic-impregnated polymethylmethacrylate. The construct functions like a conventional total hip prosthesis but is intended to be utilized as a temporary implant in patients undergoing a two-stage approach to the management of an infection at the site of a total hip arthroplasty. Figs. 1-A, 1-B, and 1-C This sixty-nine-year-old patient presented with disabling pain seven years after a primary total hip arthroplasty. Fig. 1-A The preoperative anteroposterior radiograph shows loose …