Incidence and risk factors for surgical infection after total knee replacement

Surgical site infection (SSI) after total knee replacement (TKR) is a devastating complication. We performed a retrospective study of all consecutive TKRs performed during a 2-y period. Surgical site infection (SSI) was defined by standard criteria. All patients were examined 1 y following surgery. Of 180 patients undergoing TKR, 10 (5.6%) developed a superficial (3, 1.7%) or deep (7, 3.9%) SSI. Two independent risk factors for SSI were detected: left knees became infected more often (9/ 92, 9.8%) than right knees (1/88, 1.1%) (Relative Risk 6.7 +/- 95% CI 1.7-26.8); and 7/72 (9.7%) patients receiving a type-1 prosthesis developed infection versus 3/104 (3.1%) receiving a type-2 prosthesis (RR 4.7, 95% CI 1.18-18.4). Investigation of the operating room revealed 3 problems: there was significant traffic through the door on the left of the patient; a nonstandard horizontal-flow air conditioner had been installed above that door; a tool-washing sink was in use on the other side of that door. Infection control guidelines were rehearsed: the sink was removed, the air conditioner was disconnected, and the door was locked. In a prospective survey performed 2 y later only 1/45 patients (2.2%) undergoing TKR developed a superficial SSI (p = 0.5). Correction of independent risk factors for infection following TKR led to a decrease in SSI rate.     

Prosthetic joint infection after total hip or knee arthroplasty in rheumatoid arthritis patients treated with nonbiologic and biologic disease-modifying antirheumatic drugs

The aim of this study was to identify risk factors for acute surgical-site infection (SSI) after total joint arthroplasty in rheumatoid arthritis (RA) patients treated with nonbiologic and biologic disease-modifying antirheumatic drugs (DMARDs). We performed a retrospective study of all consecutive total hip (THA) and total knee (TKA) arthroplasties performed during a 5-year period (THA 81; TKA 339). Multivariate logistic regression analysis was performed to identify SSI risk factors. Of the patients undergoing THA or TKA, 24 cases (5.7%) developed a superficial incisional SSI requiring the use of antibiotics and three cases (0.7%) developed an organ/space SSI necessitating surgical treatment to remove the artificial joint prosthesis. Multivariate logistic regression analysis revealed that the use of biologic DMARDs [P = 0.0007, odds ratio (OR) = 5.69; 95% confidence interval (CI) 2.07–15.61] and longer RA duration (P = 0.0003, OR = 1.09; 95% CI 1.04–1.14) were the only significant risk factors for acute SSI. Furthermore, an analysis that individually evaluated major agents (n > 10) adjusted for disease duration indicated that tumor necrosis factor alpha blockers increased the risk of SSI (infliximab P = 0.001, OR = 9.80, 95% CI 2.41–39.82; etanercept P = 0.0003, OR = 9.16, 95% CI 2.77–30.25). We found that the use of infliximab or etanercept and longer disease duration were associated with an increased risk of acute SSI in RA patients. Prospective studies are thus needed to determine the safety of biologic DMARDs in the perioperative period.     

Alignment of lower extremity in rheumatoid arthritis patients with a history of both total hip replacement and total knee replacement]

OBJECTIVE: The following is a retrospective study on lower extremity alignment of rheumatoid arthritis (RA) patients with a history of both Total Hip Replacement (THR) and Total Knee Replacement (TKR). METHODS: From 1992 to 2000, our department had 26 rheumatoid arthritis patients who underwent both THR and TKR. We classified these patients into three groups based on radiographic alignment of the lower extremities in the standing position: Knock-knee (valgus deformity of the knees), Bowleg (varus deformity of the knees) and Windswept Deformity (one knee in severe varus alignment with the other in severe valgus alignment). Furthermore, we identified dominant weight bearing points of the hip as classified by the following new criteria: Central Shift, Lateral Shift, and Upward Shift. Mal-alignment was then evaluated based on these two classification systems. RESULTS: Of the 26 patients, 22 patients met our criteria and 4 did not. In mal-alignment, we had 11 cases in the knock-knee group, 5 cases in the bowleg group, and 6 cases in the Windswept deformity. Using the new criteria, central shift had 6 cases; lateral shift had 6 cases; and upward shift had 10 cases. The groups of Lateral shift and Central shift demonstrated deformities of the lower extremities were influenced by moving weight bearing points, pelvis obliquity, and adduction contractures of the hip joint. In upward shift, weight bearing lines did not change. Consequently, destruction of the joint in this group progressed symmetrically. Windswept deformity was asymmetric and had severe destruction on the other side of the knee and forefoot. DISCUSSION: Moving of weight bearing point, pelvis obliquity, and adduction contractures of the hip joint affected the severity of mal-alignment of the lower extremities.     

Amyloidosis associated with rheumatoid arthritis after total joint replacement]

Rheumatoid arthritis patients who had secondary amyloidosis have been studied retrospectively. There were eight patients out of 105 rheumatoid arthritis patients who had total joint replacement surgery from 1979 to 1990 in our institute. The grade of inflammation, renal and hepatic function have been compared with the RA patients without amyloidosis pre- and post- operatively. All of eight patients was female, and their average age at the diagnosis of amyloidosis was 57.8 year-old (range 4-76 year-old). The average preoperative period was 14.4 years (range 4-27 years), and the secondary amyloidosis had been diagnosed at the time of 3.8 years (range 1-9 years) after operation. The major clinical features leading to the diagnosis were gastrointestinal disturbance in six cases and renal dysfunction in two cases. The data of the renal function of amyloidosis patients showed slightly lower than that of the RA patients without amyloidosis, and showed significantly decrease postoperatively. The white blood cell (WBC) count was higher at the time of operation in the amyloidosis patients and showed continuous increase postoperatively. Lansbury index, alpha 2-globulin and WBC count did not improve in the amyloidosis patients during three years after operation. On the contrary, the patients without amyloidosis improved in these clinical data during the same period. Three amyloidosis patients died of renal failure and one died of bronchopneumonia. The average survival period was 1.8 years (range 1-5 years) after diagnosis of amyloidosis, and was 6.3 years (range 2-10 years) after operation in these four patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Listeria monocytogenes infection in a prosthetic knee joint in rheumatoid arthritis.

The prosthetic knee joint of a 64 year old woman with severe rheumatoid arthritis was found to be infected with Listeria monocytogenes. After treatment with intravenous antibiotics, symptoms gradually resolved. She subsequently received prolonged treatment with oral co-trimoxazole and 18 months later remained well.     

Sexual difficulties and total hip replacement in rheumatoid arthritis

Fifty-three patients with rheumatoid arthritis were interviewed by questionnaire. All the patients had undergone total hip replacement and were married at the time of operation. They were asked if they had had sexual difficulties because of hip pain or stiffness and if the hip operation had in any way alleviated these problems. Forty-four of the 53 patients answered the questionnaire. Twenty-eight patients had had sexual problems which they attributed to hip symptoms. Following total hip replacement the hips of 27 patients were no longer considered to be the cause of sexual difficulties, but in 10 of those patients other problems still rendered sexual life difficult.     

Incidence of hip involvement and need for total hip replacement in rheumatoid arthritis. An eight-year follow-up study

In an 8-year follow-up of a prospective study of recent arthritis, 103 patients were found to have erosive and 97% seropositive rheumatoid arthritis. A 20% incidence of hip joint involvement was observed among them. Moderate radiological changes could be seen in 10%, severe destruction (Larsen 4 or 5) in 3%, and acetabular protrusion in 1% of the patients. It was estimated that the minimum annual need of total hip replacement in rheumatoid arthritis in Finland would be 470. This is about 100 per million in the overall population. At the end of the follow-up the Larsen X-ray index was highly significantly (p less than 0.001), ESR significantly (p less than 0.005), and CRP clearly (p less than 0.03) higher in the 13 patients with radiologically confirmed hip changes than in the 90 without them. Thus their hip destruction is attributable to a more severe disease condition and not to the glucocorticoids administered. Furthermore, HLA-B27 was positive in 69% of the above-mentioned 13 patients compared with 27% of the rest, and this difference (p less than 0.005) may also explain the poor prognosis for true rheumatoid arthritis patients.     

The impact of total joint replacement in rheumatoid arthritis

Management of the patient with rheumatoid arthritis (RA) requires a multidisciplinary approach, the role of the surgeon being to improve functional ability for the patient by reconstructing a deteriorated joint by total joint arthroplasty (TJA). An advantage of prosthetic evaluation over pharmacological medication evaluations is that the 'compliance' of the patient with the treatment (i.e. the TJA) is 100%, even at long-term follow-up. However, long-term follow-up of prosthesis evaluation is as difficult as the evaluation of any other intervention. Although the goal of any intervention on an RA patient is to improve functional ability, and thus self-support, of the patient, objective evaluation of the surgical procedure, and of its impact on the patient, can be difficult. The potential chronic course of RA makes evaluation of a specific surgical procedure and its effect on the patient difficult to interpret. The success of the TJA is generally judged on a survivorship analysis at 10 or 15 years in national registries (i.e. >40000 implants); revision surgery is used as an end-point for survival of the TJA. With a mean 90% survival at 10-year follow-up, total hip arthroplasty and total knee arthroplasty may be considered gold-standard TJA procedures for the patient. While revision is the end-point, the course to this end-point starts with progressive micromotion of the prosthesis. The effect of prosthetic changes, and of medication on prosthesis migration, can be measured very accurately by radiostereometry. The latter measures the actual performance of the TJA in the bone. Next to these more procedure-oriented evaluations, patient-oriented evaluations (e.g. quality of life, patient expectations) are of importance in judging the impact of the TJA on the RA patient. These evaluations provide evidence that the pre-operative status of the joint/extremity determines the extent of post-operative functional gain. Thus, postponing TJA for too long will give less functional benefit.     

Prevention of symptomatic thrombosis with short term (low molecular weight) heparin in patients with rheumatoid arthritis after hip or knee replacement

The need for prevention of venous thromboembolism (VTE) after total hip or knee replacement is obvious. However, the optimal regimen to achieve this remains to be defined. In patients with rheumatoid arthritis (RA) long term coumarins may not be necessary owing to the use of non-steroidal anti-inflammatory drugs (NSAIDs). 103 patients in whom 151 surgical procedures were performed (55 hip and 96 knee prostheses) were treated only with short term subcutaneous heparin. NSAIDs were used daily in 85% of the patients, and they were continued after hospital discharge. Only one patient developed symptomatic deep venous thrombosis during one year follow up. Bleeding complications were seen in 20/151 (13%) of the surgical procedures, all clinically judged as minor, and recovery was not delayed except in one case. Short term (low molecular weight) heparin appears to be an adequate, simple, and safe method for prevention of symptomatic VTE in patients with RA after knee or hip replacement, though further studies are necessary to confirm these preliminary findings.     

Acupuncture needle-associated prosthetic knee infection after total knee arthroplasty

Abstract

The case of a patient who previously had permanent acupuncture needles placed in the knee joint and had been doing well, with no evidence of infection, but who eventually underwent a revision total knee arthroplasty due to acupuncture needle-associated prosthetic infection is presented. The microorganism responsible for the infection was Enterococcus faecalis, a bacterium which rarely causes infection following arthroplasty. This case should be highlighted to increase the awareness of healthcare providers to acupuncture-associated subclinical infection that may be exacerbated by surgical manipulation.     

Acupuncture needle-associated prosthetic knee infection after total knee arthroplasty

The case of a patient who previously had permanent acupuncture needles placed in the knee joint and had been doing well, with no evidence of infection, but who eventually underwent a revision total knee arthroplasty due to acupuncture needle-associated prosthetic infection is presented. The microorganism responsible for the infection was Enterococcus faecalis, a bacterium which rarely causes infection following arthroplasty. This case should be highlighted to increase the awareness of healthcare providers to acupuncture-associated subclinical infection that may be exacerbated by surgical manipulation.     

Risk factors for venous thromboembolism after total hip and knee replacement surgery

Elective total hip and total knee arthroplasty surgeries are associated with an extraordinarily high incidence of asymptomatic venous thromboembolism (VTE). Symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) is diagnosed in only 2%-4% of these patients. A number of studies have defined the incidence and time course of symptomatic thromboembolism after these procedures. Knee arthroplasty is associated with a very high incidence of asymptomatic calf vein thrombosis, with almost all symptomatic VTE events diagnosed in the first 21 days after surgery. Hip arthroplasty, however, is associated with a higher incidence of asymptomatic proximal thrombi and a modestly higher incidence of symptomatic VTE events, many diagnosed up to 6 or 8 weeks after hospital discharge. Extended medical thromboprophylaxis has been shown to reduce the incidence of symptomatic and asymptomatic VTE among hip arthroplasty patients but not among knee arthroplasty patients. Risk factors for VTE after knee arthroplasty are not well defined. Important risk factors that have been shown to be associated with the development of VTE after hip surgery include (1) a history of prior VTE, (2) obesity (body mass index > 25), (3) delay in ambulation after surgery, and (4) female sex. Factors associated with lower risk include (1) Asian/Pacific Islander ethnicity, (2) use of pneumatic compression among non-obese patients after surgery, and (3) extended thromboprophylaxis after hospital discharge.