Antibiotic Laden Bone Cement Does Not Reduce Acute Periprosthetic Joint Infection Risk in Primary Total Knee Arthroplasty.

BACKGROUND: Periprosthetic joint infection (PJI) can be a serious complication of total knee arthroplasty (TKA). A method believed to decrease the incidence of PJI is antibiotic-laden bone cement (ALBC). Current clinical practice guidelines do not recommend ALBC in primary TKA. The purpose of this study was to compare ALBC to plain cement (PC) in preventing PJI in primary TKA. METHODS: This retrospective analysis included 109,242 Medicare patients in the American Joint Replacement Registry who underwent a cemented primary TKA from January 2017 to March 2021, and had at least 1 year of follow-up. Patients who received ALBC were compared to patients who received PC. Demographic and case-specific variables such as age, sex, race, body mass index, Charlson Comorbidity Index, anesthesia type, and operative time were used to create propensity scores. A logistic regression was run to predict the probability of receiving ALBC. Also, a multivariate model was run on the full unstratified population, using the same covariates as were used to create the propensity model. The primary outcome was differences in PJI rates. RESULTS: Logistic regression analysis showed that a higher preoperative diagnosis of osteoarthritis, higher Charlson Comorbidity Index, higher body mass index, women, race, and anesthesia requirements increased a patient's probability of receiving ALBC. In the full unstratified multivariate model, ALBC did not show a statistically significant difference in risk of revision for infection compared to PC. CONCLUSIONS: The use of ALBC in primary TKA has not been shown to be more efficacious in preventing PJI within the population of Medicare patients in the United States. However, this study is limited given it is a retrospective database study that may inherently have biases and the large dataset has a potential for overpowering the findings.

The Anatomic Position of the Sciatic Nerve During Percutaneous Retrograde Posterior Column Fixation Is Determined by Hip Position.

OBJECTIVES: There are multiple established patient positions for placement of a percutaneous retrograde posterior column screw for fixation of acetabulum fractures. The sciatic nerve is at risk of injury during this procedure because it lies adjacent to the start point at the ischial tuberosity. The purpose of this study was to define how the position of the sciatic nerve, relative to the ischial tuberosity, changes regarding the patient's hip position. METHODS: In a cohort of 11 healthy volunteers, ultrasound was used to measure the absolute distance between the ischial tuberosity and the sciatic nerve. Measurements were made with the hip and knee flexed to 90 degrees to simulate supine and lateral positioning and with the hip extended to simulate prone positioning. In both positions, the hip was kept in neutral abduction and neutral rotation. RESULTS: The distance from the lateral border of the ischial tuberosity to the medial border of the sciatic nerve was greater in all subjects in the hip-flexed position versus the extended position. The mean distance was 17 mm (range, 14-27 mm) in the hip-extended position and 39 mm (range, 26-56 mm) in the hip-flexed position ( P < 0.001). CONCLUSIONS: The sciatic nerve demonstrates marked excursion away from the ischial tuberosity when the hip is flexed compared with when it is extended. The safest patient position for percutaneous placement of a retrograde posterior column screw is lateral or supine with the hip flexed to 90 degrees.

The Effect of Online Prescription Drug Monitoring on Opioid Prescription Habits After Elective Single-level Lumbar Fusion.

INTRODUCTION: The United States opioid epidemic is a well-documented crisis stemming from increased prescriptions of narcotics. Online prescription drug monitoring programs (PDMPs) are a potential resource to mitigate narcotic misuse by tracking controlled substance prescriptions. Therefore, the purpose of this study was to evaluate opioid prescription trends after implementation of an online PDMP in patients who underwent single-level lumbar fusion. METHODS: Patients who underwent a single-level lumbar fusion between August 27, 2017, and August 31, 2020, were identified and placed categorically into one of two cohorts: an "early adoption" cohort, September 1, 2017, to August 31, 2018, and a "late adoption" cohort, September 1, 2019, to August 31, 2020. This allowed for a 1-year washout period after Pennsylvania PDMP implementation on August 26, 2016. Opioid use data were obtained by searching for each patient in the state government's online PDMP and recording data from the year before and the year after the patient's procedure. RESULTS: No significant difference was observed in preoperative opioid prescriptions between the early and late adoption cohorts. The late adoption group independently predicted decreased postoperative opioid prescriptions (ß, 0.78; 95% confidence interval [CI], 0.65 to 0.93; P = 0.007), opioid prescribers (ß, 0.81; 95% CI, 0.72 to 0.90; P < 0.001), pharmacies used (ß, 0.90; 95% CI, 0.83 to 0.97; P = 0.006), opioid pills (ß, 0.61; 95% CI, 0.50 to 0.74; P < 0.001), days of opioid prescription (ß, 0.57; 95% CI, 0.45 to 0.72; P < 0.001), and morphine milligram equivalents prescribed (ß, 0.53; 95% CI, 0.43 to 0.66; P < 0.001). CONCLUSIONS: PDMP implementation was associated with decreased postoperative opioid prescription patterns but not preoperative opioid prescribing behaviors. LEVELS OF EVIDENCE: 4.

Risk Factors for 30-day and 90-day Readmission After Lumbar Decompression.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To assess readmission rates and risk factors for 30-day and 90-day readmission after elective lumbar decompression at a single institution. SUMMARY OF BACKGROUND DATA: Hospital readmission is an undesirable aspect of interventional treatment. Studies evaluating readmissions after elective lumbar decompression typically analyze national databases, and therefore have several drawbacks inherent to their macroscopic nature that limit their clinical utility. METHODS: Patients undergoing primary one- to four-level lumbar decompression surgery were retrospectively identified. Demographic, surgical, and readmission data within "30-days" (0-30 days) and "90-days" (31-90 days) postoperatively were extracted from electronic medical records. Patients were categorized into four groups: (1) no readmission, (2) readmission during the 30-day or 90-day postoperative period, (3) complication related to surgery, and (4) Emergency Department (ED)/Observational (OBs)/Urgent (UC) care. RESULTS: A total of 2635 patients were included. Seventy-six (2.9%) were readmitted at some point within the 30- (2.3%) or 90-day (0.3%) postoperative periods. Patients in the pooled readmitted group were older (63.1 yr, P  < 0.001), had a higher American Society of Anesthesiologists (ASA) grade (31.2% with ASA of 3, P = 0.03), and more often had liver disease (8.1%, P = 0.004) or rheumatoid arthritis (12.0%, P = 0.02) than other cohorts. A greater proportion of 90-day readmissions and complications had surgical-related diagnoses or a diagnosis of recurrent disc herniation than 30-day readmissions and complications (66.7% vs. 44.5%, P = 0.04 and 33.3% vs. 5.5%, P < 0.001, respectively). Age (Odds ratio [OR]: 1.02, P = 0.01), current smoking status (OR: 2.38, P < 0.001), longer length of stay (OR: 1.14, P < 0.001), and a history of renal failure (OR: 2.59, P = 0.03) were independently associated with readmission or complication. CONCLUSION: Increased age, current smoking status, hospital length of stay, and a history of renal failure were found to be significant independent predictors of inpatient readmission or complication after lumbar decompression.

The role of electrical stimulation for rehabilitation and regeneration after spinal cord injury.

Electrical stimulation is used to elicit muscle contraction and can be utilized for neurorehabilitation following spinal cord injury when paired with voluntary motor training. This technology is now an important therapeutic intervention that results in improvement in motor function in patients with spinal cord injuries. The purpose of this review is to summarize the various forms of electrical stimulation technology that exist and their applications. Furthermore, this paper addresses the potential future of the technology.

Clinical Results of Revision Hip Arthroplasty for Neck-Taper Corrosion and Adverse Local Tissue Reactions Around a Modular Neck Stem.

BACKGROUND: Adverse local tissue reactions (ALTRs) around a modular neck stem at our institution lead to a 13.5% rate of revision. The purpose of this study was to report the clinical results of revision total hip arthroplasty (THA) in this patient population. METHODS: We identified 80 hips in 77 patients who underwent revision THA due to neck-stem corrosion. Intraoperative and postoperative complications, clinical outcomes, re-revision rates, and the postoperative ion levels were recorded. RESULTS: The mean follow-up period after revision was 45.3 ± 16.3 months (range 24-81 months). There were no intraoperative mechanical complications during the revision surgery. Eight hips (10%) had postoperative complications related to the revision implant, of which 6/8 came to re-revision: postoperative implant dislocation in 4 hips-2 treated nonsurgically, aseptic loosening of femoral component in 2 hips, and periprosthetic femoral fracture in 2 hips. No patients had recurrence of ALTR nor the recurrence of groin pain within the follow-up period. With 2 exceptions, ion levels normalized within one year of the revision surgery. The survival rate was 94% (95% confidence interval 84-98) at 32 months and 82% (95% confidence interval 56-93) at 63 months after revision THA (using re-revision THA due to any reason as the endpoint). CONCLUSION: Intraoperative complication, postoperative complication, and re-revision rates are equivalent to femoral revision surgeries for other causes (infection, fracture, loosening). We recommend selecting revision-type stems to minimize the risk of femoral loosening or periprosthetic fracture, and larger femoral heads or dual mobility bearings to minimize the risk of dislocation.

Patients With Modular-Neck Total Hip Arthroplasty: A Brief Five-Year Follow-Up Study.

BACKGROUND: We have previously reported the early clinical results of a modular-neck stem identifying an early 2-year revision rate of 13% due to neck-stem corrosion. This report updates our findings to a midterm mean follow-up of 5 years. METHODS: This is a consecutive retrospective review of 186 modular-neck hips in 175 patients with a mean follow-up period was 60.1 ± 22.9 months (range 24-100). We reviewed clinical findings, routine radiographs, detailed imaging (metal artifact reduction software-magnetic resonance imaging, ultrasound), and serum ion levels of cobalt and chromium. We performed a survival analysis with the endpoint defined as revision total hip arthroplasty due to neck-stem corrosion. RESULTS: We revised 41 hips (22.0%) for neck-stem corrosion. Clinical symptoms (groin pain ± local swelling) were consistently present in those that came for revision. Mean serum cobalt ion levels increased as time passed in all patients. Detailed image findings showed that larger fluid collections and local soft tissue masses were seen predominately in symptomatic patients. However, 14% of patients who underwent revision did not have positive magnetic resonance imaging or ultrasound findings. The survival rate was 87% (95% confidence interval 81-92) at 3 years postoperatively and 72% (95% confidence interval 64-80) at 7 years postoperatively. CONCLUSION: The revision rate for this modular-neck stem due to neck-stem corrosion at mid-term follow-up almost doubled in comparison to previous short-term results. It seems reasonable to consider clinical follow-up alone as symptoms, rather than blood testing for ion levels, seem to be the defining characteristic of failure.

Large variations in clinical antibiotic activity against Staphylococcus aureus biofilms of periprosthetic joint infection isolates.

Staphylococcus aureus biofilms have a high tolerance to antibiotics, making the treatment of periprosthetic joint infection (PJI) challenging. From a clinical perspective, bacteria from surgical specimens are cultured in a planktonic state to determine antibiotic sensitivity. However, S. aureus exists primarily as established biofilms in PJI. To address this dichotomy, we developed a prospective registry of total knee and hip arthroplasty PJI S. aureus isolates to quantify the activity of clinically important antibiotics against isolates grown as biofilms. S. aureus planktonic minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were assessed using clinical laboratory standard index assays for 10 antibiotics (cefazolin, clindamycin, vancomycin, rifampin, linezolid, nafcillin, gentamicin, trimethoprim/sulfamethoxazole, doxycycline, and daptomycin). Mature biofilms of each strain were grown in vitro, after which biofilm MIC (MBIC) and biofilm MBC (MBBC) were determined. Overall, isolates grown as biofilms displayed larger variations in antibiotic MICs as compared to planktonic MIC values. Only rifampin, doxycycline, and daptomycin had measurable biofilm MIC values across all S. aureus isolates tested. Biofilm MBC observations complemented biofilm MIC observations; rifampin, doxycycline, and daptomycin were the only antibiotics with measurable biofilm MBC values. 90% of S. aureus biofilms could be killed by rifampin, 50% by doxycycline, and only 15% by daptomycin. Biofilm formation increased bacterial antibiotic tolerance nonspecifically across all antibiotics, in both MSSA and MRSA samples. Rifampin and doxycycline were the most effective antibiotics at killing established S. aureus biofilms. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1604-1609, 2019.