Mark J. Spangehl

Inflammatory blood laboratory levels as markers of prosthetic joint infection: A systematic review and meta-analysis

BACKGROUND The preoperative diagnosis of prosthetic joint infection in patients with a total hip or knee arthroplasty may rely in part on the use of systemic inflammation markers. These markers have unclear accuracy. The objective of this review was to summarize the evidence on the accuracy of the peripheral white blood-cell count, the erythrocyte sedimentation rate, serum C-reactive protein levels, and serum interleukin-6 levels for the diagnosis of prosthetic joint infection. METHODS We searched electronic databases (MEDLINE, EMBASE, Cochrane Library, Web of Science, and Scopus) from 1950 through 2009. Eligible studies evaluated the accuracy of white blood-cell count, erythrocyte sedimentation rate, serum C-reactive protein level, and serum interleukin-6 level for the intraoperative diagnosis of prosthetic joint infection at the time of revision arthroplasty. Two reviewers working independently extracted study characteristics and data to estimate the diagnostic odds ratio and 95% confidence interval for each result. RESULTS We included thirty eligible studies that included 3909 revision total hip or knee arthroplasties. The prevalence of prosthetic joint infection was 32.5% (1270 of 3909). The accuracy of assessed inflammation markers, represented with a diagnostic odds ratio, was 314.7 (95% confidence interval, 113.0 to 876.8) for interleukin-6 (three studies), 13.1 (95% confidence interval, 7.9 to 21.7) for C-reactive protein level (twenty-three studies), 7.2 (95% confidence interval, 4.7 to 10.9) for erythrocyte sedimentation rate (twenty-five studies), and 4.4 (95% confidence interval, 2.9 to 6.6) for white blood-cell count (fifteen studies). CONCLUSIONS The diagnostic accuracy for prosthetic joint infection was best for interleukin-6, followed by C-reactive protein level, erythrocyte sedimentation rate, and white blood-cell count. Given the limited numbers of studies assessing interleukin-6 levels, further investigations assessing the accuracy of interleukin-6 for the diagnosis of prosthetic joint infection are warranted.

Diagnosis of periprosthetic joint infections of the hip and knee.

&NA; No preferred test for diagnosis of periprosthetic joint infection exists, and the algorithm for the workup of patients suspected of infection remains unclear. The work group evaluated the available literature to determine the role of each diagnostic modality and devise a practical algorithm that allows physicians to reach diagnosis of periprosthetic joint infection. Ten of the 15 recommendations have strong or moderate evidence in support. These include matters involving erythrocyte sedimentation rate and C‐reactive protein level testing, knee and hip aspiration, and stopping the use of antibiotics prior to obtaining intra‐articular cultures. The group recommends against the use of intraoperative Gram stain but does recommend the use of frozen sections of peri‐implant tissues in reoperation patients in whom infection has not been established, as well as multiple cultures in reoperation patients being assessed for infection. The group recommends against initiating antibiotic treatment in patients with suspected infection until after joint cultures have been obtained, but recommends that prophylactic preop‐erative antibiotics not be withheld in patients at lower probability for infection.

American Academy of Orthopaedic Surgeons clinical practice guideline on: the diagnosis of periprosthetic joint infections of the hip and knee.

AAOS Guideline on The Diagnosis of Periprosthetic Joint Infections of the Hip and Knee Summary of Recommendations The following is a summary of the recommendations in the AAOS’ clinical practice guideline, The Diagnosis of Periprosthetic Joint Infections of the Hip and Knee. This summary does not contain rationales that explain how and why these recommendations were developed nor does it contain the evidence supporting these recommendations. All readers of this summary are strongly encouraged to consult the full guideline and evidence report for this information. We are confident that those who read the full guideline and evidence report will note that the recommendations were developed using systematic evidence-based processes designed to combat bias, enhance transparency, and promote reproducibility. This summary of recommendations is not intended to stand alone. Clinical decisions should be made in light of all circumstances presented by the patient. Procedures applicable to the individual patient rely on mutual communication between patient, physician, and other healthcare practitioners. 1. In the absence of reliable evidence about risk stratification of patients with a potential periprosthetic joint infection, it is the opinion of the work group that testing strategies be planned …

Treatment of the infected hip replacement.

Selection of the suitable treatment method for an infected hip arthroplasty requires careful assessment of patient-related variables and expected treatment goals. The basic treatment options include antibiotic suppression, open debridement, resection arthroplasty, arthrodesis, reimplantation of another prosthesis, and amputation. Successful treatment of infection requires complete debridement of all infected and foreign material and appropriate antimicrobial therapy. When possible, the preferred treatment approach is insertion of another prosthesis with a delayed reconstructive treatment technique. Patients now are presenting with an increasing incidence of resistant organisms and severe bone loss, which increases the difficulty of treatment.

Total Knee Arthroplasty Following Proximal Tibial Osteotomy: Risk Factors for Failure

BACKGROUND The results of proximal tibial osteotomy are known to deteriorate over time, with the majority of patients eventually requiring total knee arthroplasty. The outcome of total knee arthroplasty in patients who have had a proximal tibial osteotomy, compared with that of routine primary total knee arthroplasty, remains controversial. The purpose of the present study was to evaluate the long-term clinical and radiographic outcome of total knee arthroplasty in patients who had undergone a previous proximal tibial osteotomy and to identify the risk factors that may result in an inferior outcome. METHODS Between 1980 and 1990, 166 cemented condylar total knee prostheses were implanted in 118 patients who had had a previous proximal tibial osteotomy for the treatment of osteoarthritis. The study group included seventy-seven men and forty-one women who had a mean age of 69.1 years at the time of knee arthroplasty. The average interval between the osteotomy and the total knee arthroplasty was 8.6 years. The average duration of clinical follow-up was 15.1 years, and the average duration of radiographic follow-up was 9.2 years. RESULTS The mean Knee Society pain score improved from 34.5 to 82.9 points, and the mean function score improved from 44.6 to 88.1 points. There was also a substantial improvement in the mean arc of motion. Thirteen knees (8%) were revised at a mean of 5.9 years. At the time of the final follow-up, progressive complete radiolucent lines indicating a loose prosthesis were present around seventeen tibial components and seven femoral components. CONCLUSIONS There was a very high rate of radiographic evidence of loosening. Male gender, increased weight, young age at the time of total knee arthroplasty, coronal laxity, and preoperative limb malalignment were identified as risk factors for early failure. Despite these findings, total knee arthroplasty can provide reliable and durable pain relief and improvement in function for patients who have had a previous proximal tibial osteotomy. LEVEL OF EVIDENCE Prognostic study. Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.

Uncemented acetabular components with bulk femoral head autograft for acetabular reconstruction in developmental dysplasia of the hip: results at five to twelve years.

Background: Anterolateral acetabular bone deficiency is one of the technical problems associated with total hip arthroplasty in patients with developmental hip dysplasia. The purpose of this study was to evaluate the results of one method of acetabular reconstruction for hip dysplasia—placement of an uncemented socket in conjunction with a bulk femoral head autograft. Methods: Forty-four hips in thirty-five patients (twenty-nine female and six male; average age, thirty-nine years) with developmental hip dysplasia were treated with primary total hip arthroplasty with use of an uncemented porous-coated titanium cup fixed with screws and an autogenous bulk femoral head graft. The patients were followed clinically in a prospective fashion for five to 12.3 years (mean, 7.5 years), and radiographs were analyzed retrospectively. Results: Four acetabular components were revised: two, because of severe polyethylene wear and osteolysis; one, because of aseptic loosening; and one, because of fracture of the acetabular shell. The mean Harris hip score for the unrevised hips improved from 51 points preoperatively to 91 points postoperatively. No unrevised socket had definite radiographic evidence of loosening. Forty-three of the forty-four hips had no radiographic evidence of resorption of the graft or had radiographic evidence of resorption limited to the nonstressed area of the graft lateral to the edge of the cup. Conclusions: This method of reconstruction provided reliable acetabular fixation and appeared to restore acetabular bone stock in patients with developmental hip dysplasia. We use this technique for patients with moderate anterolateral acetabular bone deficiency requiring total hip arthroplasty.

The Alpha Defensin-1 Biomarker Assay can be Used to Evaluate the Potentially Infected Total Joint Arthroplasty

BackgroundDiagnosing a periprosthetic joint infection (PJI) requires a complex approach using various laboratory and clinical criteria. A novel approach to diagnosing these infections uses synovial fluid biomarkers. Alpha defensin-1 (AD-1) is one such synovial-fluid biomarker. However little is known about the performance of the AD-1 assay in the diagnosis of PJI.Questions/purposesWe sought to (1) determine the sensitivity and specificity of the AD-1 assay in a population of patients being evaluated for PJI, using the Musculoskeletal Infection Society (MSIS) criteria as the reference standard, and (2) compare the AD-1 assay with other currently available clinical tests, specifically cell count, culture, erythrocyte sedimentation rate, and C-reactive protein.Patients and MethodsA retrospective review was performed of all patients undergoing workup for a PJI at our institution from January to June 2013. Sixty-one AD-1 assays were done in 57 patients. The group included 51 patients with 55 painful joints and six patients who underwent aspiration before second-stage reimplantation. Patients were considered to have a PJI if they met the MSIS criteria. We calculated the sensitivity and specificity of the AD-1 synovial fluid assay, and compared it with the sensitivity and specificity of the synovial fluid cell count, culture, erythrocyte sedimentation rate, and C-reactive protein. There were 19 diagnosed infections in the 61 aspirations, with 21 positive and 40 negative AD-1 assays. There were two false positive and no false negatives AD-1 assays.ResultsThe sensitivity and specificity for the AD-1 assay were 100% (95% CI, 79%–100%) and 95% (95% CI, 83%–99%), respectively. The sensitivity and specificity of the other tests ranged from 68% to 95% and 66% to 88%, respectively. The AD-1 assay results outperformed the other tests but did not reach statistical significance except for the sensitivity of the erythrocyte sedimentation rate.ConclusionThe sensitivity and specificity of the synovial fluid AD-1 assay exceeded the sensitivity and specificity of the other currently available clinical tests evaluated here but did not reach significance. The AD-1 assay offers another test with high sensitivity and specificity for diagnosing a PJI especially in the case where the diagnosis of PJI is uncertain, but larger studies will be needed to determine significance and cost effectiveness.Level of EvidenceLevel III, diagnostic study. See the Instructions for Authors for a complete description of levels of evidence.

Effect of Body Mass Index on Limb Alignment After Total Knee Arthroplasty

Prior studies have reported increased failure rates in obese patients with postoperative limb mal-alignment. This study was undertaken to determine if a relationship exists between postoperative limb alignment and BMI in patients undergoing primary TKA performed with mechanical instruments. An IRB-approved retrospective review of 196 knees was undertaken. Limb alignment was determined on full-length, standing, hip-to-ankle x-rays, preoperatively and postoperatively. The effects of gender, side, preoperative mechanical alignment and BMI on postoperative alignment were analyzed via multivariate regression analysis. Both preoperative mechanical limb alignment (P<0.001) and BMI (P=0.009) had a significant effect on postoperative limb alignment following TKA performed with mechanical instruments.

Five cases of failure of the tibial polyethylene insert locking mechanism in one design of constrained knee arthroplasty.

We describe 5 cases of failure of the locking mechanism of the polyethylene insert and tibial base-plate in one design of constrained condylar knee prosthesis due to disengagement of the locking screw. Loosening of the screw is believed to occur because of a counterclockwise torque created by the axial rotation of the femur on the tibia that occurs as the knee extends during gait. This torque is transmitted via the highly rotationally constrained femoral housing and tibial post to the locking screw. These failures suggest that an alternative locking mechanism should be considered for this prosthesis.

Prophylactic flap reconstruction of the knee prior to total knee arthroplasty in high-risk patients.

Insufficient soft-tissue coverage following total knee arthroplasty (TKA) may threaten prosthesis retention or compromise joint function. A retrospective review was conducted of all patients who underwent prophylactic flap reconstruction of the knee prior to TKA or salvage flap reconstruction over a 6-year period. Twenty-three patients underwent prophylactic flap reconstruction. Complications at the time of flap transfer were common (48%), however, all flaps survived. All 23 successfully completed subsequent TKA with no wound complications occurring at the time of TKA. Complications in the salvage group were also frequent (44%) and 3 required above knee amputation. Postoperative range of motion was significantly better in the prophylactic group, as well as when cutaneous flaps were chosen. Prophylactic flap reconstruction of the knee prior to TKA in high-risk patients is an excellent option in this small subset of patients, many of whom would not be offered TKA without addressing the compromised soft-tissue envelope first.