Extended Oral Antibiotics Increase Bacterial Resistance in Patients Who Fail 2-Stage Exchange for Periprosthetic Joint Infection.

BACKGROUND: Although studies have demonstrated reductions in recurrent periprosthetic joint infection (PJI) with the administration of prolonged oral antibiotics at second-stage reimplantation, the potential for increasing bacterial resistance has not been studied. The purpose of this study was to determine if oral antibiotics at second-stage reimplantation increased the rate of antibiotic resistance in subsequent infections. METHODS: We retrospectively reviewed patients who underwent 2-stage exchange for chronic PJI from 2014 to 2019. We compared those who had received prolonged oral antibiotics at the time of stage 2 reimplantation with those who did not. The primary outcome was the presence of resistant organisms in any subsequent infection. The secondary outcome was the overall rate of recurrent PJI in the 2 groups. Multivariable analyses controlling for demographics and comorbid conditions were used. RESULTS: Of the 211 patients who underwent 2-stage exchange for PJI, 158 patients received prolonged oral antibiotics. The mean follow-up was 2.2 years. Recurrent PJI was diagnosed in 24 of 158 (15%) patients who received oral antibiotics compared with 11 of 53 (21%) patients who did not receive antibiotics (P = .35). PJI with resistant organisms was identified in 16 of 24 (67%) patients who received antibiotics compared with 0 of 11 (0%) patients who did not receive antibiotics (P = .0001). CONCLUSIONS: Prolonged oral antibiotics following 2-stage exchange increase drug resistance to that antibiotic in subsequent PJI. We recommend further research in the area to refine antimicrobial protocols as we consider the risks and benefits of prolonged antibiotic treatment.

Inpatient Versus Outpatient Hip and Knee Arthroplasty: Which Has Higher Patient Satisfaction?

BACKGROUND: More surgeons are offering patients the option of having adult reconstructive procedures performed as an outpatient at an ambulatory surgery center. However, it is unknown if these patients have higher or lower satisfaction with their care than patients having a traditional inpatient stay. The purpose of this study is to compare satisfaction between inpatients and outpatients undergoing hip or knee arthroplasty. METHODS: Portions of the Health Consumer Assessment of Healthcare Providers and Systems survey, the Friends and Family Test, and 8 additional questions were administered to 174 consecutive patients. There were 8 non-responders (95.4% response rate) leaving 102 who underwent inpatient and 64 who had outpatient surgery. Responses were stratified using the "boxes" scoring approach as recommended by Health Consumer Assessment of Healthcare Providers and Systems and analyzed with a chi-squared or Fischer's exact test where appropriate. Power analysis determined that 38 patients per group were needed to detect a 1-point difference in overall satisfaction between groups with 80% power and alpha of 0.05 considered significant. RESULTS: Outpatients responded with more top responses when asked about the staff's explanation of any medicines received (91.4% vs 77.5%, P = .026), the staff's assistance with their pain management (98.3% vs 88.0%, P = .022), the written health information they were given upon discharge (98.3% vs 90.1%, P = .05), and the courtesy and respect from the nurses (100.0% vs 92.2%, P = .022). Inpatients responded with more bottom responses when asked how prepared they felt for discharge home (8.9% vs 0.0%, P = .014). Top responses in overall satisfaction with the facility (87.1% vs 93.4%, P = .204) and overall experience (89.2% vs 95.2%, P = .177) were similar between inpatients and outpatients, respectively. Not surprisingly, inpatients were older (64.1 vs 59.2 years, P = .001), heavier (body mass index 32.7 vs 30.4, P = .035), and had higher Charlson comorbidity scores (2.6 vs 1.9, P = .002). CONCLUSION: Although satisfaction was high in both groups, when differences were present they favored outpatient surgery in the ambulatory surgery center.

Synovial Fluid Alpha-Defensin Is an Adjunctive Tool in the Equivocal Diagnosis of Periprosthetic Joint Infection.

BACKGROUND: Synovial fluid alpha-defensin has shown to be a reliable diagnostic test for the diagnosis of periprosthetic joint infection (PJI), but its use in equivocal cases has yet to be established. The purpose of this study was to determine the reliability of alpha-defensin testing in patients, where the diagnosis of PJI was unclear. METHODS: A consecutive series of 41 synovial aspirations by a single surgeon that were sent for alpha-defensin testing in equivocal cases of PJI were retrospectively reviewed. Indications for alpha-defensin testing included recent antibiotic use, borderline synovial fluid cell count, and differential, suspected culture-negative infection, and suspected false-positive culture. PJI was diagnosed using the Musculoskeletal Infection Society (MSIS) criteria. RESULTS: Of the 39 aspirations in 32 patients included in the study, there were 33 (85%) knee and 6 (15%) hip samples. Eleven (28%) samples met MSIS criteria for PJI. Of the 23 samples that had recent antibiotic use (6 MSIS positive, 17 negative), alpha-defensin results confirmed the correct MSIS diagnosis in 19 (83%) samples. Of the 11 samples in which alpha-defensin testing was performed for a borderline cell count (3 MSIS positive, 8 negative), alpha-defensin confirmed the MSIS diagnosis in 10 of 11 (91%) samples. Finally, among the 5 samples with suspected false-positive or false-negative cultures (2 MSIS positive, 3 negative), alpha-defensin confirmed the correct diagnosis in 3 (60%) samples. The overall sensitivity, specificity, negative predictive value, and positive predictive value of synovial alpha-defensin were 82%, 82%, 92%, and 64%, respectively. CONCLUSION: In patients for whom the diagnosis of PJI is unclear because of recent antibiotic use, equivocal laboratory findings, or suspected false-negative or false-positive cultures, synovial fluid alpha-defensin can provide an additional data point to assist the clinician in determining whether PJI is present but is prone to false-positive results in this challenging population.

Trends in the Use of High-Viscosity Cement in Patients Undergoing Primary Total Knee Arthroplasty in the United States.

BACKGROUND: Aseptic loosening remains the most common mode of failure following total knee arthroplasty (TKA). Although the risk of loosening is multifactorial, recent studies reported early failure via debonding at the tibial implant-cement interface and a potential association with high viscosity cement (HVC). The purpose of this study is to determine the type of cement used by surgeons performing elective, primary TKA in the United States. METHODS: A retrospective cohort study was performed using data reported to the American Joint Replacement Registry from 2012 to 2017. The primary variable assessed was the type of cement used in each primary TKA, categorized as HVC, medium viscosity cement, or low viscosity cement based on the manufacturer's specifications. The use of antibiotic-impregnated cement was also assessed. RESULTS: A total of 554,935 primary TKA procedures were reviewed over the 7-year period. The use of HVC steadily increased from 46.0% of TKAs in 2012 to 61.3% of TKAs in 2017. Conversely, the use of low viscosity cement decreased in use from 47.9% of TKAs in 2012 to 30.9% in 2017. The percentage of TKAs performed using antibiotic-impregnated cement also decreased from 44.2% in 2012 to 34.5% in 2017. CONCLUSION: This study demonstrates that the percentage of TKAs performed using HVC has continued to increase over the most recent 7 years for which the American Joint Replacement Registry has data. The risk of aseptic loosening is clearly multifactorial, but close monitoring is necessary to determine whether this change in surgeon preference will affect component survivorship.

Serum Metal Levels for Diagnosis of Adverse Local Tissue Reactions Secondary to Corrosion in Metal-on-Polyethylene Total Hip Arthroplasty.

BACKGROUND: Recently, corrosion at the head-neck junction in metal-on-polyethylene bearing surface total hip arthroplasty (THA) has been recognized as a cause of adverse local tissue reactions (ALTRs). Serum metal levels have been advocated as a tool for the diagnosis of ALTR; however, no prior studies have specifically examined their utility. The purpose of this study was to determine the optimal cutoff values for serum cobalt and chromium levels in diagnosing ALTR after metal-on-polyethylene bearing surface THA. METHODS: We reviewed 447 consecutive patients with serum metal levels tested at our institution and identified 64 patients with a metal-on-polyethylene bearing who had axial imaging or underwent reoperation to confirm the presence or absence of ALTR. Receiver-operating characteristic curves were produced to identify cutoff thresholds to optimize sensitivity, and diagnostic test performance was characterized. RESULTS: Forty-four of the 64 patients (69%) were positive for an ALTR. The best test for the diagnosis of ALTR was the serum cobalt level (area under the curve [AUC] = 99%). A threshold cutoff of ≥1.0 ng/mL had a sensitivity of 100%, specificity of 90%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 100%. Serum chromium levels were also diagnostic (AUC = 87%). A threshold cutoff of ≥0.15 ng/mL had a sensitivity of 100%, specificity of 50%, PPV of 81%, and NPV of 100%. Finally, serum cobalt-to-chromium ratio was also helpful for diagnosis (AUC = 90%). A threshold cutoff value of 1.4 for the cobalt-to-chromium ratio offered a sensitivity of 93%, specificity of 70%, PPV of 87%, and NPV of 82%. CONCLUSION: Measurement of serum cobalt level with a threshold value of 1.0 ng/mL in our experience is the best test for identifying the presence of ALTR in patients with a metal-on-polyethylene THA. Measurement of chromium level and the ratio of cobalt-to-chromium levels are also of value.

Multiple Osteochondral Allograft Transplantation with Concomitant Tibial Tubercle Osteotomy for Multifocal Chondral Disease of the Knee.

Symptomatic patellofemoral chondral lesions are a challenging clinical entity, as these defects may result from persistent lateral patellar maltracking or repetitive microtrauma. Anteromedializing tibial tubercle osteotomy has been shown to be an effective strategy for primary and adjunctive treatment of focal or diffuse patellofemoral disease to improve the biomechanical loading environment. Similarly, osteochondral allograft transplantation has proven efficacy in physiologically young, high-demand patients with condylar or patellofemoral lesions, particularly without early arthritic progression. The authors present the surgical management of a young athlete with symptomatic tricompartmental focal chondral defects with fresh osteochondral allograft transplantation and anteromedializing tibial tubercle osteotomy.

Systematic Review and Meta-Analysis of Recombinant Human Bone Morphogenetic Protein-2 in Localized Alveolar Ridge and Maxillary Sinus Augmentation.

PURPOSE: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is approved by the Food and Drug Administration as a viable alternative to bone graft in spinal fusion and maxillary sinus lift. The research questions for meta-analysis were: Is rhBMP-2 an effective bone graft substitute in localized alveolar ridge augmentation and maxillary sinus floor augmentation? What are the potential adverse events? MATERIALS AND METHODS: A search of MEDLINE from January 1980 to January 2014 using PubMed, the Cochrane Database of Systematic Reviews and Controlled Trials, CINAHL, and EMBASE was performed. Searches were performed from Medical Subject Headings. The quality of each study included was graded by Review Manager software. The primary outcome variable was bone formation measured as change in bone height on computed tomogram. A systematic review of adverse events also was performed. A random-effects model was chosen. Continuous variables were calculated using the standardized mean difference and 95% confidence intervals (CIs) comparing improvement from baseline of the experimental group with that of the control group. Change in bone height was calculated using logarithmic odds ratio. Test of significance used the Z statistic with a P value of .05. RESULTS: Ten studies met the criteria for systematic review; 8 studies were included in the meta-analysis. Five studies assessed localized alveolar ridge augmentation and resulted in an overall standardized mean difference of 0.56 (CI, 0.20-0.92) in favor of BMP; this result was statistically important. Three studies assessed maxillary sinus floor augmentation and resulted in an overall standardized mean difference of -0.50 (CI, -0.93 to -0.09), which was meaningfully different in favor of the control group. Adverse events were inconsistently reported, ranging from no complications to widespread adverse events. CONCLUSION: For localized alveolar ridge augmentation, this meta-analysis showed that rhBMP-2 substantially increases bone height. However, rhBMP-2 does not perform as well as the autograft or allograft in maxillary sinus floor augmentation. Long-term clinical success and adverse events need to be reported with more consistency before definitive conclusions can be made.

A population-based review of bone morphogenetic protein: associated complication and reoperation rates after lumbar spinal fusion.

OBJECT The authors compared the rates of postoperative adverse events and reoperation of patients who underwent lumbar spinal fusion with bone morphogenetic protein (BMP) to those of patients who underwent lumbar spinal fusion without BMP. METHODS The authors retrospectively analyzed the PearlDiver Technologies, Inc., database, which contains the Medicare Standard Analytical Files, the Medicare Carrier Files, the PearlDiver Private Payer Database (UnitedHealthcare), and select state all-payer data sets, from 2005 to 2010. They identified patients who underwent lumbar spinal fusion with and without BMP. The ICD-9-CM code 84.52 was used to identify patients who underwent spinal fusion with BMP. ICD-9-CM diagnosis codes identified complications that occurred during the initial hospital stay. ICD-9-CM procedural codes were used to identify reoperations within 90 days of the index procedure. The relative risks (and 95% CIs) of BMP use compared with no BMP use (control) were calculated for the association of any complication with BMP use compared with the control. RESULTS Between 2005 and 2010, 460,773 patients who underwent lumbar spinal fusion were identified. BMP was used in 30.7% of these patients. The overall complication rate in the BMP group was 18.2% compared with 18.7% in the control group. The relative risk of BMP use compared with no BMP use was 0.976 (95% CI 0.963-0.989), which indicates a significantly lower overall complication rate in the BMP group (p < 0.001). In both treatment groups, patients older than 65 years had a statistically significant higher rate of postoperative complications than younger patients (p < 0.001). CONCLUSIONS In this large-scale institutionalized database study, BMP use did not seem to increase the overall risk of developing a postoperative complication after lumbar spinal fusion surgery.

Distal Biceps Tendon Ruptures: An Epidemiological Analysis Using a Large Population Database.

BACKGROUND: The incidence of distal biceps tendon ruptures was studied more than 10 years ago in a small patient cohort. Recent diagnostic advancements have improved the ability to detect this rare injury. HYPOTHESIS: The incidence of distal biceps tendon ruptures will be significantly greater than previously reported. STUDY DESIGN: Descriptive epidemiologic study. METHODS: A query of the PearlDiver Technologies national database containing public and private insurance patients was used to estimate the national incidence of distal biceps tendon ruptures in the United States. A retrospective chart review of our local population identified demographic groups and risk factors that increased likelihood of injury. RESULTS: The estimated national incidence of distal biceps tendon rupture was 2.55 per 100,000 patient-years. The local incidence was 5.35 per 100,000 patient-years. The mean and median ages of patients in our regional cohort were 46.3 and 46 years, respectively. Males composed the majority of the injured population (national 95%, regional 96%). Smoking and elevated body mass index were found to be associated with increased likelihood of injury, while diabetes mellitus showed no association. CONCLUSION: The incidence of distal biceps tendon ruptures in this study was higher than previously reported.

Bone morphogenetic protein-associated complications in pediatric spinal fusion in the early postoperative period: an analysis of 4658 patients and review of the literature.

OBJECT: Use of recombinant human bone morphogenetic protein-2 has risen steadily since its approval by the FDA for use in anterior lumbar interbody fusion in 2002. The FDA has not approved the use of bone morphogenetic protein (BMP) in children. Age less than 18 years or lack of evidence of epiphyseal closure are considered by the manufacturer to be contraindications to BMP use. In light of this, the authors performed a query of the database of one of the nation's largest health insurance companies to determine the rate of BMP use and complications in pediatric patients undergoing spinal fusion. METHODS: The authors used the PearlDiver Technologies private payer database containing all records from United Health-Care from 2005 to 2011 to query all cases of pediatric spinal fusion with or without BMP use. A review of the literature was also performed to examine the complications associated with BMP use in pediatric spinal fusion. RESULTS: A total of 4658 patients underwent spinal fusion. The majority was female (65.4%), and the vast majority was age 10-19 years (94.98%) and underwent thoracolumbar fusion (93.13%). Bone morphogenetic protein was used in 1752 spinal fusions (37.61%). There was no difference in the rate of BMP use when comparing male and female patients or age 10 years or older versus less than 10 years. Anterior cervical fusions were significantly less likely to use BMP (7.3%). Complications occurred in 9.82% of patients treated with versus 9.88% of patients treated without BMP. The complication rate was nearly identical in male versus female patients and in patients older versus younger than 10 years. Comparison of systemic, wound-related, CNS, and other complications showed no difference between groups treated with and without BMP. The reoperation rate was also nearly identical. CONCLUSIONS: Bone morphogenetic protein is used in a higher than expected percentage of pediatric spinal fusions. The rate of acute complications in these operations does not appear to be different in patients treated with versus those treated without BMP. Caution must be exercised in interpreting these data due to the many limitations of the administrative database as a data source, including the short length of follow-up.

Cancer risk from bone morphogenetic protein exposure in spinal arthrodesis.

BACKGROUND: The U.S. Food and Drug Administration reported a higher incidence of cancer in patients who had spinal arthrodesis and were exposed to a high dose of recombinant human bone morphogenetic protein-2 (rhBMP-2) compared with the control group in a randomized controlled trial. The purpose of this study was to determine the risk of cancer after spinal arthrodesis with BMP. METHODS: We retrospectively analyzed the incidence of cancer in 467,916 Medicare patients undergoing spinal arthrodesis from 2005 to 2010. Patients with a preexisting diagnosis of cancer were excluded. The average follow-up duration was 2.85 years for the BMP group and 2.94 years for the control group. The main outcome measure was the relative risk of developing new malignant lesions after spinal arthrodesis with or without exposure to BMP. RESULTS: The relative risk of developing cancer after BMP exposure was 0.938 (95% confidence interval [95% CI]: 0.913 to 0.964), which was significant. In the BMP group, 5.9% of the patients developed an invasive cancer compared with 6.5% of the patients in the control group. The relative risk of developing cancer after BMP exposure was 0.98 in males (95% CI: 0.94 to 1.02) and 0.93 (95% CI: 0.90 to 0.97) in females. The control group showed a higher incidence of each type of cancer except pancreatic cancer. CONCLUSIONS: Recent clinical use of BMP was not associated with a detectable increase in the risk of cancer within a mean 2.9-year time window. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.