Aaron J. Johnson

Understanding the physiological basis of physical resilience to clinical stressors is crucial for the well‐being of older adults. This article presents a novel framework to discover the biological underpinnings of physical resilience in older adults as part of the “Characterizing Resiliencies to Physical Stressors in Older Adults: A Dynamical Physiological Systems Approach” study, also known as The Study of Physical Resilience and Aging (SPRING). Physical resilience, defined as the capacity of a person to withstand clinical stressors and quickly recover or improve upon a baseline functional level, is examined in adults aged 55 years and older by studying the dynamics of stress response systems. The hypothesis is that well‐regulated stress response systems promote physical resilience. The study employs dynamic stimulation tests to assess energy metabolism, the hypothalamic–pituitary–adrenal axis, the autonomic nervous system, and the innate immune system. Baseline characteristics influencing resilience outcomes are identified through deep phenotyping of physical and cognitive function, as well as of biological, environmental, and psychosocial characteristics. SPRING aims to study participants undergoing knee replacement surgery ( n = 100), bone and marrow transplantation ( n = 100), or anticipating dialysis initiation ( n = 60). Phenotypic and functional measures are collected pre‐stressor and at multiple times after stressor for up to 12 months to examine resilience trajectories. By improving our understanding of physical resilience in older adults, SPRING has the potential to enhance resilient outcomes to major clinical stressors. The article provides an overview of the study's background, rationale, design, pilot phase, implementation, and implications for improving the health and well‐being of older adults.

Background: Next-generation DNA sequencing (NGS) detects bacteria-specific DNA corresponding to the 16S ribosomal RNA gene and can identify bacterial presence with greater accuracy than traditional culture methods. The clinical relevance of these findings is unknown. The purpose of the present study was to compare the results from bacterial culture and NGS in order to characterize the potential use of NGS in orthopaedic trauma patients. Methods: A prospective cohort study was performed at a single academic, level-I trauma center. Three patient groups were enrolled: (1) patients undergoing surgical treatment of acute closed fractures (presumed to have no bacteria), (2) patients undergoing implant removal at the site of a healed fracture without infection, and (3) patients undergoing a first procedure for the treatment of a fracture nonunion who might or might not have subclinical infection. Surgical site tissue was sent for culture and NGS. The proportions of culture and NGS positivity were compared among the groups. The agreement between culture and NGS results was assessed with use of the Cohen kappa statistic. Results: Bacterial cultures were positive in 9 of 111 surgical sites (110 patients), whereas NGS was positive in 27 of 111 surgical sites (110 patients). Significantly more cases were positive on NGS as compared with culture (24% vs. 8.1%; p = 0.001), primarily in the acute closed fracture group. No difference was found in terms of the percent positivity of NGS when comparing the acute closed fracture, implant removal, and nonunion groups. With respect to bacterial identification, culture and NGS agreed in 73% of cases (κ = 0.051; 95% confidence interval, −0.12 to 0.22) indicating only slight agreement compared with expected chance agreement of 50%. Conclusions: NGS identified bacterial presence more frequently than culture, but with only slight agreement between culture and NGS. It is possible that the increased frequency of bacterial detection with molecular methods is reflective of biofilm presence on metal or colonization with nonpathogenic bacteria, as culture methods have selection pressure posed by restrictive, artificial growth conditions and there are low metabolic activity and replication rates of bacteria in biofilms. Our data suggest that NGS should not currently substitute for or complement conventional culture in orthopaedic trauma cases with low suspicion of infection. Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The number of liver transplant recipients (LTR) is worldwide increasing and, as the survival is improving as well, there is an increasing number of patients needing total hip arthroplasty (THA). There might be increased risks for this specific group of patients and due to their comorbidities costs might be higher too. Using a big national database outcome and cost of THA should be compared between liver transplant recipients and the general population. The study was performed using a collection of Medicare, Medicaid, and private insurance claims. Length of stay (LOS), 30-day readmissions, complications rates up to 5 years, and 90-day total cost of care between liver transplant recipients and matched non-transplant patients should be compared. All primary THAs from 2010 to 2019 were identified. 513 patients with a liver transplant before their THA were matched to 10,759 patients without a history of solid organ transplant at a 1:20 ratio based on age, sex, Charlson Comorbidity Index, obesity, and diabetes status. LTR had a longer average LOS (4.2 vs. 3.4 days, p < 0.001). There was no difference in the thirty-day readmissions (5.7% vs. 4.1%, p = 0.117) and 90-day dislocation rates (2.9% vs. 2.4%, p = 0.600). Total costs in the first ninety days after THA were not different between the LTR and controls (p = 0.756). These findings suggest that complications and costs are no major point of concern in patients with liver transplant that are operated with THA.

Background: Renal transplants are the most commonly performed solid-organ transplants worldwide. It is unclear whether a kidney transplant is associated with reduced postoperative complications in comparison with patients on dialysis for end-stage renal disease (ESRD). The purpose of this study was to utilize a national database to compare readmissions, complications, and costs associated with primary total hip arthroplasty (THA) between matched renal transplant recipients (RTRs) and patients on dialysis for ESRD. Methods: Patients with a renal transplant (N = 1,401) and those on dialysis for ESRD (without a transplant) (N = 1,463) prior to being treated with a THA from 2010 to 2019 were identified within the PearlDiver database. RTRs and patients on renal dialysis were frequency-matched 1:1 on the basis of 9 patient characteristics, resulting in 582 patients in each group. Length of hospital stay, readmissions, complication rates up to 2 years, and total costs up to 1 year were compared between the groups using chi-square and multivariable logistic regression analyses to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results: Patients on renal dialysis had an increased mean length of stay (6.3 days) compared with RTRs (4.6 days, p < 0.01). After adjusting for age, tobacco use, and diabetes, patients on renal dialysis were more likely to be readmitted by 90 days (OR = 1.59; CI = 1.11 to 2.29, p < 0.01) and have mechanical complications (OR = 2.13; CI = 1.08 to 4.45, p = 0.03) and revisions (OR = 2.14; CI = 1.14 to 4.01, p = 0.01) by 2 years. Patients on renal dialysis were also more likely to have periprosthetic joint infections at 1 year (OR = 1.91; CI = 1.02 to 3.71, p = 0.04). Patients on dialysis incurred 14% higher costs at 1 year (p = 0.11). Conclusions: Patients on renal dialysis had more readmissions, complications, and costs after THA when compared with RTRs. Specifically, patients on renal dialysis were more likely to have longer index lengths of stay, more readmissions by 90 days, and more mechanical complications and revision surgery by 2 years. Patients on dialysis also incurred higher costs and had greater odds of PJI. These results suggest that joint surgeons may consider delaying THA in suitable patients until after renal transplantation to reduce postoperative complications and costs. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

This is a case of a 72 year old male with a chronic methicillin-resistant Staphylococcus aureus prosthetic joint infection. After the third intravenous dose of bacteriophage therapy, an unusual, reversible transaminitis prompted stoppage of bacteriophage therapy. Nevertheless, treatment was successful and the patient’s severe chronic infection was eradicated.

Background: Periprosthetic fracture is a leading reason for readmission following total hip arthroplasty. Most of these fractures occur during the early postoperative period before bone ingrowth. Before ingrowth occurs, the femoral component can rotate relative to the femoral canal, causing a spiral fracture pattern. We sought to evaluate, in a paired cadaver model, whether the torsional load to fracture was higher in collared stems. The hypothesis was that collared stems have greater load to fracture under axial and torsional loads compared with collarless stems. Methods: Twenty-two cadaveric femora (11 matched pairs) with a mean age of 77 ± 10.2 years (range, 54 to 90 years) were harvested. Following dissection, the femora were evaluated with use of a dual x-ray absorptiometry scanner and T scores were recorded. We utilized a common stem that is available with the same intraosseous geometry with and without a collar. For each pair, 1 femur was implanted with a collared stem and the contralateral femur was implanted with a collarless stem with use of a standard broaching technique. A compressive 68-kg load was applied to simulate body weight during ambulation. A rotational displacement was then applied until fracture occurred. Peak torque prior to fracture was measured with use of a torque meter load cell and data acquisition software. Results: The median torque to fracture was 65.4 Nm for collared stems and 43.1 Nm for uncollared stems (p = 0.0014, Wilcoxon signed-rank test). The median T score was –1.95 (range, –4.1 to –0.15). The median difference in torque to fracture was 29.18 Nm. As expected in each case, the mode of failure was a spiral fracture around the implant. Conclusions: Collared stems seemed to offer a protective effect in torsional loading in this biomechanical model comparing matched femora. Clinical Relevance: These results may translate into a protective effect against early periprosthetic Vancouver B2 femoral fractures that occur before osseous integration has occurred.