Therapeutic Efficacy of an Erythromycin-Loaded Coaxial Nanofiber Coating in a Rat Model of S. aureus-Induced Periprosthetic Joint Infection.

Implant surface nanofiber (NF) coatings represent an alternative way to prevent/treat periprosthetic joint infection (PJI) via local drug release. We developed and characterized a coaxial erythromycin (EM)-doped PLGA/PCL-PVA NF coating. The purpose of this study was to determine the efficacy of EM-NF coatings (EM0, no EM, EM100 (100 mg/mL), and EM1000 (1000 mg/mL) wt/wt) in a rat PJI model. A strong bond of the EM-NF coating to the surface of titanium (Ti) pins was confirmed by in vitro mechanical testing. Micro-computed tomography (mCT) analysis showed that both EM100 and EM1000 NF effectively reduced periprosthetic osteolysis compared to EM0 at 8 and 16 weeks after implantation. Histology showed that EM100 and EM1000 coatings effectively controlled infection and enhanced periprosthetic new bone formation. The bone implant contact (BIC) of EM100 (35.08%) was higher than negative controls and EM0 (3.43% and 0%, respectively). The bone area fraction occupancy (BAFO) of EM100 (0.63 mm2) was greater than controls and EM0 (0.390 mm2 and 0.0 mm2, respectively). The BAFO of EM100 was higher than that of EM1000 (0.3 mm2). These findings may provide a basis for a new implant surface fabrication strategy aimed at reducing the risks of defective osseointegration and PJI.

Effect of Commercially Available Wound Irrigation Solutions on Uninfected Host Tissue in a Murine Model.

Background: Commercially available irrigation solutions are used to reduce bacterial contamination and prevent surgical site infections. However, the effect of these solutions on the healing capacity of tissue has not been well-established. The purpose of this study was to investigate the effects of 5 commercially available irrigation solutions on host tissue in a murine model. Methods: There were 5 treatment groups: bacitracin, Clorpactin, Irrisept, Prontosan, Bactisure, and normal saline control. The irrigation solutions were applied to the wound for 30 seconds or 1 minute, as per the manufacturer's instructions, and then washed with normal saline. Mice were sacrificed at 3 days and 10 days. The tissue was examined histologically for inflammation, edema, granulation tissue formation, and re-epithelialization. Granulation tissue formation and re-epithelialization were surrogates for effective wound healing. Results: All of the irrigation solutions had negative effects on host tissue in the acute phase. The inflammation and edema were improved in the later phase (10 days). Recovery and healing of the open wounds were observed for all groups at 10 days. The antiseptic irrigation solutions had similar cytotoxic effects on host tissue at 3 days and did not have delayed or compromised wound healing at 10 days when compared to normal saline control. Conclusions: Single short-duration use of these commercially available antiseptic irrigation solutions appears to be safe in an uninfected wound. Data from this study will provide surgeons with useful information regarding the safety of using antiseptic wound irrigation solutions intraoperatively for prevention of surgical site infections.

Midline Sacral Fractures: Review of the Literature.

INTRODUCTION: Sacral fractures are an important consideration in high-energy traumas associated with injuries to the pelvic ring that confer much of pelvic stability. A midline longitudinal sacral fracture (MLS) is a relatively rare fracture pattern, with only 23 cases of MLS fractures reported in the literature to date. This systematic review evaluates overall mechanisms of MLS injury, associated injuries, complications, management, and fracture prognosis. METHODS: A 1952-2021 PubMed literature search yielded 11 publications reporting the outcomes of a total of 23 MLS fracture cases. RESULTS: Of the 23 MLS patients, 15 (65%) were male and eight (35%) were female, with an average age of 37.25. Ten (43.5%) MLS fractures occurred during motor vehicle collisions and eight (34.7%) because of motorcycle accidents. The most common pelvic ring injuries associated with MLS were pubic symphysis diastasis (n = 12, 57%) and pubic ramus fractures (n = 11, 48%). Patients most frequently suffered intra-pelvic organ dysfunction such as sexual dysfunction or bowel/bladder/urethral injuries. Fractures were treated both operatively or non-operatively and generally showed clinical meaningful resolution at 10 weeks post-injury. CONCLUSIONS: MLS injuries most often occur in high-energy trauma due to motor vehicle or motorcycle accidents as well as crush injuries, leg splitting, direct perineal/perianal impacts. Pre-trauma sacral abnormalities could be potentially predisposing factors correlated with MLS fractures. Careful review of x-rays and CT scans may help reveal MLS fractures, which can go initially undiagnosed. Operative and nonoperative management strategies includes bedrest, transsacral transiliac screw, decompressive laminotomies, and/or pelvic external fixation. The outcomes reported to date have been generally favorable, with most patients healing at approximately 10 weeks. Keywords: Midline sacral fracture; vertical sacral fracture; sacrum; pelvic ring injury.

The Differential Effect of COVID on Total Joint Arthroplasty Between Hospital and Ambulatory Surgery Centers/Hospital Outpatient Departments: A Michigan Arthroplasty Registry Collaborative Quality Initiative Analysis.

Background: Coronavirus disease (COVID) created unprecedented challenges, especially for high-volume elective subspecialties like total joint arthroplasty. Limited inpatient capacity and resource conservation led to new outpatient selection criteria and site of service changes. As a Michigan Arthroplasty Registry Quality Collaborative Initiative quality project, demographic changes, complications, and differential effects on inpatient vs outpatient centers pre- and post-COVID were analyzed. Methods: The registry identified all total joint arthroplasty at hospitals and ASCs/HOPDs between 07/2019-12/2019 and 07/2020-12/2020. These intervals represented pre-COVID and post-COVID elective surgery shutdowns. Case volumes, demographics, and 90-day complications were compared. Results: Comparing 2020 to 2019, hospital volumes decreased (-9% total hip arthroplasty [THA], -17% total knee arthroplasty [TKA]), and ambulatory surgery center (ASC)/hospital outpatient department (HOPD) increased (+84% THA, +125% TKA). Entering 2020, ASC/HOPD patients were older (P = .0031, P < .0001: THA, TKA), had more American Society of Anesthesiologists score 3-4 (P = .0105, P = .0021), fewer attended joint class (P < .0001, P < .0001), and more hips were women (P = .023). Hospital patients had higher preoperative pain scores (P = .0117, P < .0001; THA, TKA), less joint education attendance (P < .0001, P < .0001), younger TKAs (P = .0169), and more American Society of Anesthesiologists score 3-4 (0.0009). After propensity matching, there were no significant differences between site of service for 90-day fractures, deep vein thromboses or pulmonary embolisms, infection, or hip dislocations. Hospital THAs had higher readmissions (P = .0003) and TKAs had higher 30-day emergency department visits (P = .005). ASC/HOPD patients were prescribed higher oral morphine equivalents (P < .0001, P < .0001; THA, TKA). Conclusions: COVID's elective surgery shutdown caused a dramatic site of service shift. Traditional preoperative education was negatively impacted, and older and sicker patients became outpatients. But short-term complications were not increased in ASCs/HOPDs. These site of service and associated patient demographic changes may be safely sustained.

Early Survivorship of Uncemented Total Knee Arthroplasty Varies by Age and Sex Based on Data From the Michigan Arthroplasty Registry Collaborative Quality Initiative.

BACKGROUND: Outcome data for newer uncemented total knee arthroplasty (TKA) designs has been mixed. Registry studies showed worse survivorship, but clinical trials have not demonstrated differences compared to cemented designs. There has been renewed interest in uncemented TKA with modern designs and improved technology. The utilizations of uncemented knees in Michigan, 2-year outcomes, and the effects of age and sex were evaluated. METHODS: A statewide database from 2017 through 2019 was analyzed for incidence, distribution, and early survivorship of cemented versus uncemented TKAs. There was 2-year minimum follow-up. Kaplan-Meier survival analysis was used to generate time to first revision cumulative percent revision curves. The impacts of age and sex were examined. RESULTS: Use of uncemented TKAs increased from 7.0 to 11.3%. Uncemented TKAs were more commonly men, younger, heavier, American Society of Anesthesiologists score > 2, and opioid users (P < .05). At 2 years, overall cumulative percent revision was higher in uncemented (2.44% [2.00, 2.99]) versus cemented (1.76% [1.64, 1.89]), particularly in women uncemented (2.41 [1.87, 3.12]) versus cemented (1.64 [1.50, 1.80]). Revision rates were greater with uncemented women >70 years (1.2% 1 year, 1.02% 2 years) versus < 70 years (0.56%, 0.53%), notably uncemented were inferior in both groups (P < .05). Men, regardless of age, had similar survivorships with both cemented and uncemented designs. CONCLUSION: The use of an uncemented TKA had an increased risk of early revision compared to cemented. This finding, however, was only apparent in women, especially those >70 years old. Surgeons should consider cement fixation in women >70 years.

High-Energy Blast Injury Requiring Transradial Amputation with Associated Essex Lopresti and Terrible Triad Injuries of the Elbow: A Rare Presentation.

CASE: Blast injuries to the upper extremity can be devastating and emotionally stressful injuries. We describe a case of a high-energy blast injury to an upper extremity from an explosive. The transfer of energy caused severe soft tissue/bony damage to the hand, but also led to associated Essex Lopresti and terrible triad injuries. The patient required emergent transradial amputation by hand surgery as well as definitive fixation by our orthopaedic team. CONCLUSION: We describe a unique salvage operation that established forearm pronosupination, elbow flexion, and proper prosthetic fitting. We feel that describing our technique could help others in treating this injury if encountered.