Faculty Bibliography

Achieving the appropriate primary stability for immediate or early loading in areas with low-density bone, such as the posterior maxilla, is challenging. A three-dimensional (3D) stabilization implant design featuring a tapered body with continuous cutting flutes along the length of the external thread form, with a combination of curved and linear geometric surfaces on the thread's crest, has the capacity to enhance early biomechanical and osseointegration outcomes compared to implants with traditional buttressed thread profiles. Commercially available implants with a buttress thread design (TP), and an experimental implant that incorporated the 3D stabilization trimmed-thread design (TP 3DS) were used in this study. Six osteotomies were surgically created in the ilium of adult sheep (N = 14). Osteotomy sites were randomized to receive either the TP or TP 3DS implant to reduce site bias. Subjects were allowed to heal for either 3 or 12 weeks (N = 7 sheep/time point), after which samples were collected en bloc (including the implants and surrounding bone) and implants were either subjected to bench-top biomechanical testing (e.g., lateral loading), histological/histomorphometric analysis, or nanoindentation testing. Both implant designs yielded high insertion torque (ITV ≥ 30 N⋅cm) and implant stability quotient (ISQ ≥ 70) values, indicative of high primary stability. Qualitative histomorphological analysis revealed that the TP 3DS group exhibited a continuous bone-implant interface along the threaded region, in contrast to the TP group at the early, 3-week, healing time point. Furthermore, TP 3DS's cutting flutes along the entire length of the implant permitted the distribution of autologous bone chips within the healing chambers. Histological evaluation at 12 weeks revealed an increase in woven bone containing a greater presence of lacunae within the healing chambers in both groups, consistent with an intramembranous-like healing pattern and absence of bone dieback. The TP 3DS macrogeometry yielded a ~66% increase in average lateral load during pushout testing at baseline (T = 0 weeks, p = 0.036) and significantly higher bone-to-implant contact (BIC) values at 3 weeks post-implantation (p = 0.006), relative to the traditional TP implant. In a low-density (Type IV) bone model, the TP 3DS implant demonstrated improved performance compared to the conventional TP, as evidenced by an increase in baseline lateral loading capacity and increased BIC during the early stages of osseointegration. These findings indicate that the modified implant configuration of the TP 3DS facilitates more favorable biomechanical integration and may promote more rapid and stable bone anchorage under compromised bone quality conditions. Therefore, such improvements could have important clinical implications for the success and longevity of dental implants placed in regions with low bone density.

The aim of the study was to assess the effect of bulk material on the reliability and failure modes of narrow-diameter implants. Narrow implants (Ø3.5 × 10 mm - 11° internal conical connection) were manufactured from three different bulk materials: commercially pure titanium grade-IV (CP4), cold-worked titanium (CW), and 4Titude (4Ti), and were evaluated under fatigue testing. Eighteen samples per group were tested under step-stress accelerated life testing through 30° off-axis load application in mild, moderate, and aggressive loading profiles. The number of cycles and load at failure were used to calculate use-level probability curves and reliability for missions of 100,000 cycles up to 200 N, followed by fractographic analyses. Beta values suggested that damage accumulation dictated failures. Reliability analyses at 80, 120, and 150 N evidenced high reliability for narrow implants independent of bulk material. At 200 N, a decrease in reliability was observed for all groups (∼46%). Failure mode analysis depicted similar failures for all groups and comprised implant fracture, abutment fracture, and implant + abutment fractures. Narrow implants presented high reliability for physiologic masticatory forces in the anterior region. Characteristic strength, reliability, and failure modes were similar regardless of bulk material, suggesting that fatigue damage accumulation at thin wall implants dictated failure over bulk material strength.

PURPOSE/OBJECTIVE:The various physiological profiles comprising vascularized composite allografts (VCAs) pose unique challenges to preservation. Minimizing ischemia, reperfusion injury, and rejection remains a primary focus of graft pretreatments (PTs). Currently, the gold standard PT consists of flushing the graft and placing it in static cold storage in the University of Wisconsin solution. With this method, graft viability is limited to 4 to 6 hours. Prolonging this time limit will increase donor allocation radius, access to care, and positive patient outcomes. We aimed to evaluate novel PTs that could potentially enhance and lengthen VCA viability. METHODS:Following PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, we conducted a comprehensive literature search of EMBASE, Cochrane, and PubMed. Studies had to be published prior to June 15, 2022. PTs had to target cell physiology, rather than immunogenicity. We extracted data including study design, PT details, evaluation metrics, and outcomes. RESULTS:We identified 13 studies, categorized into 3 groups: solution-based alterations to the gold standard, ex vivo perfusion, and other novel techniques. The incorporation of hydrogen sulfide and Perfadex as solutions in the gold standard protocol demonstrated a 6-day delay in rejection and limited reperfusion injury markers, respectively. In an ex vivo perfusion study, after 24 hours of PT and 12 hours posttransplant, VCA muscle contractility remained close to normal. The gold standard PT did not demonstrate the same success. However, graft weight gain, up to 50% of baseline among the reviewed articles, is a prominent adverse effect of perfusion. Another technique, cryopreservation, displayed 90% graft failure by venous thrombosis, despite high free graft viability following 2 weeks of storage. CONCLUSIONS:This study of PT modalities found a variety of encouraging preservation techniques for grafts with high levels of tissue diversity. Ex vivo perfusion dominated PT innovation with promising results in preserving the viability and functionality of muscle, which is central to the restoration of movement. Future studies are necessary to evaluate long-term graft outcomes and to optimize PT protocols for extended preservation times to ensure clinical relevance.

BACKGROUND:Endovascular aortic aneurysm repair (EVAR) is utilized to treat abdominal aortic aneurysms, while patients with short infrarenal necks can undergo fenestrated EVAR (FEVAR). Previous studies have demonstrated decreased aortic neck dilation for FEVAR compared to EVAR. Sac regression is a marker of success after EVAR; however, little is known regarding changes in sac volumetrics. This study compares aortic sac regression after EVAR versus FEVAR using volumetric analysis. METHODS:A retrospective review of prospectively collected data from 120 patients who underwent EVAR was performed. Thirty patients underwent FEVAR (Cook Medical Inc, Bloomington, IN) and 90 patients underwent EVAR (30 each with Endurant [Medtronic, Dublin, Ireland], Excluder [Gore, Flagstaff, AZ], and Zenith [Cook]). Demographic data were analyzed. Using 3-dimensional reconstruction software, preoperative and postoperative aneurysm sac volumes were measured, in addition to aneurysm characteristics. RESULTS:, P = 0.005). EVAR patients had greater number of lumbar arteries (7.26 ± 1.68 vs. 5.31 ± 1.93, P < 0.000001). On postoperative follow-up, FEVAR cases had greater sac regression compared to standard EVAR (-22.75 ± 25.7% vs. -5.98 ± 19.66%, P = 0.00031). The percentage of sac regression was greater when measured by volume compared to maximum diameter for FEVAR (-22.75 ± 25.7% vs. -13.90 ± 15.4%, P = 0.01) but not EVAR (-5.98 ± 19.7% vs. -4.51 ± 15.2%, P = 0.246). Those in the top tertile of percent volume of thrombus (>48.5%) were more likely to experience greater than 10% sac regression by volume (55% vs. 33.3%, P = 0.015). On multivariate analysis, FEVAR was associated with sac regression greater than 10% by volume (odds ratio [OR] 4.325, 95% confidence interval [CI] 1.346-13.901, P = 0.014), while endoleak (OR 0.162, 95% CI 0.055-0.479, P < 0.001) and 2 patent hypogastric arteries (OR 0.066, 95% CI 0.005-0.904, P = 0.042) were predictive against. CONCLUSIONS:Fenestrated EVAR is associated with greater sac regression compared to EVAR on volumetric analysis. This difference may be attributable to decreased endotension within the aneurysm resulting from less aortic neck dilatation, while the greater proportion of thrombus may be a protective factor from growth. Patients being evaluated for EVAR with borderline neck anatomy should be considered for FEVAR given increased sac regression.

PURPOSE/UNASSIGNED:There is limited literature reporting swallowing outcomes in the pre- and postoperative period for patients undergoing facial transplantation. This case report aims to utilize a combination of objective and patient-reported outcome measures to highlight swallowing improvements following the world's first face with whole-eye transplantation. METHOD/UNASSIGNED:Outcome measures in jaw range of motion, anterior containment, texture progression, airway protection, and pharyngeal swallow function were collected pretransplantation by two speech-language pathologists (SLPs) and at multiple postoperative visits after the procedure was completed. Specific outcome measures included the Gothenburg Trismus Questionnaire, Maximal Incisor Opening, Modified Teachers Drooling Scale, Functional Oral Intake Scale, Eating Assessment Tool-10, The Penetration-Aspiration Scale, and the Modified Barium Swallow Study Impairment Profile. Measures were then compared over a 1-year time period to assess changes in swallow function. RESULTS/UNASSIGNED:Improvements in jaw range of motion, anterior containment, and airway protection were observed. The patient's stated goal of returning to full PO diet following face transplant was achieved within 1 year. CONCLUSIONS/UNASSIGNED:Swallowing and trismus outcome measures are an important tool for monitoring progress along a patient's recovery journey, especially following unique procedures such as face transplantation. Based on this single patient case study, facial transplantation can lead to improvements in both objective and patient-reported outcomes. Future goals for research should continue to explore this unique population due to the limited literature available for SLPs, as well as include development of valid and reliable assessment tools specific to the face transplantation population.

Guided bone regeneration (GBR) procedures have been indicated to enhance bone response, reliably regenerate lost tissue, and create an anatomically pleasing ridge contour for biomechanically favorable and prosthetically driven implant placement. The aim of the current study was to evaluate and compare the bone regenerative performance of deproteinized bovine bone (DBB) and deproteinized porcine bone (DPB) grafts in a beagle mandibular model for the purposes of GBR. Four bilateral defects of 10 mm × 10 mm were induced through the mandibular thickness in each of the 10 adult beagle dogs being studied. Two of the defects were filled with DPB, while the other two were filled with DBB, after which they were covered with collagen-based membranes to allow compartmentalized healing. Animals were euthanized after 6, 12, 24, or 48 weeks postoperatively. Bone regenerative capacity was evaluated by qualitative histological and quantitative microtomographic analyses. Microcomputed tomography data of the bone (%), graft (%), and space (%) were compared using a mixed model analysis. Qualitatively, no histomorphological differences in healing were observed between the DBB and DPB grafts at any time point. By 48 weeks, the xenografts (DBB and DPB) were observed to have osseointegrated with regenerating spongy bone and a close resemblance to native bone morphology. Quantitatively, a higher amount of bone (%) and a corresponding reduction in empty space (space (%)) were observed in defects treated by DBB and DPB grafts over time. However, no statistically significant differences in bone (%)were observed between DBB (71.04 ± 8.41 at 48 weeks) and DPB grafts (68.38 ± 10.30 at 48 weeks) (p > 0.05). GBR with DBB and DPB showed no signs of adverse immune response and led to similar trends in bone regeneration over 48 weeks of permitted healing.

PURPOSE/OBJECTIVE:The purpose of this study is to examine the effect of age on outcomes following repair of acute displaced patella fractures Methods: 248 patients who sustained a displaced patella fracture and underwent open reduction and internal fixation were identified. Patients included underwent a similar operative protocol, were prescribed a standard post-operative protocol of therapy, and were seen at standard follow-up intervals. Patients were divided into groups of < 65 years old (young) and ≥ 65 years old (older). Statistical analysis was run to determine if there was a significant difference in range of knee motion and rate of major complications. RESULTS:Of the 248 patients, 149 were young and 99 were older. The mean age of the older group was 74.5 ± 6.7 and the mean age of the young group was 50 ± 12. Fracture pattern and BMI were similar the groups, however the older group had a higher average CCI (p<0.001). Additionally, the groups had similar length of follow up (p=0.693) and similar mean time to radiographic healing (p=0.533). Older patients had limited knee extension at 6 months (compared young patients (p=0.031). Finally, older patients had a higher rate of all complications compared to young patients. Two percent of older patients developed a fracture related infection (FRI), 4% developed a symptomatic nonunion and 11% were underwent re-operation including removal of hardware, total knee replacement, irrigation and debridement and manipulation under anesthesia. CONCLUSION/CONCLUSIONS:Complication rates following patella fracture fixation in older patients were higher than young patients, despite having similar injury patterns, surgical treatment and follow up. These findings can better inform treating physicians during surgical intervention of older patients with patella fractures.

BACKGROUND:Implant's primary stability is determined by the intimate and immediate contact between the implant and osteotomy wall, whereas secondary stability is primarily influenced by healing chambers that facilitate the bone formation and remodeling processes following placement. Therefore, modifications to macro-geometric parameters are essential to elicit the desired in vivo response and to ensure successful osseointegration. Three-dimensional (3D) stabilization thread forms comprise both curved and linear geometric surfaces across the thread's crest maximizing retention forces while constraining lateral movement under load relative to conventional buttress-threaded implants. METHODS:This study utilized Ti-6Al-4V ELI implants with (i) a buttress thread design [Tapered Pro, BioHorizons®, Birmingham, AL, USA] (TP - control) compared to (ii) a novel, patented, 3D stabilization trimmed-thread design (TP 3DS - experimental). Implants were placed in the mandible of sheep (N = 14 sheep, 6 implants per group per sheep) and allowed to heal for 3- and 12-weeks (N = 7 sheep per time point). During implant placement (T = 0 weeks), the maximum insertion torque value (ITV) and implant stability quotient (ISQ) were measured by torque-in testing and resonance frequency analysis, respectively. After the healing periods, subjects were euthanized, and samples harvested en bloc for biomechanical evaluation via lateral loading tests in addition to histomorphometric and nanoindentation analysis. RESULTS:ITV values were significantly lower in the TP 3DS group compared to TP (p < 0.001). Both groups presented ISQ values ≥ 70, indicating high primary stability. Relative to the TP group, TP 3DS exhibited a significant (∼1.85-fold) increase in lateral load at 3 weeks (p = 0.029) and comparable load values at 12 weeks (p > 0.05). No quantitative differences in percentage of bone-to-implant contact (BIC) and bone-area-fraction-occupancy (BAFO) were observed at either time points between the two thread designs (p > 0.05). Similarly, no differences in bone's mechanical properties (Young's modulus (E) and Hardness (H)) between TP and TP 3DS were observed at 3- and 12- weeks (p > 0.05). Qualitatively, scattered microcracks were apparent at the outer threads of the implant, particularly within the TP group, whereas small bone chips were interspersed between threads of the 3DS implant serving as additional nucleation sites for bone formation. CONCLUSION/CONCLUSIONS:The TP 3DS design reduced insertion torque, improved lateral loading competence, and resulted in a healing pattern, that are beneficial during early stages of osseointegration compared to TP implants.

OBJECTIVES/OBJECTIVE:To determine the most common reason for 30-day readmission following hospitalization for hip fractures. METHODS:Design: A retrospective review. SETTING/METHODS:Single academic medical center that includes a Level 1 Trauma Center. PATIENT SELECTION CRITERIA/UNASSIGNED:Included were all patients operatively treated for hip fractures (OTA 31) between October 2014 and November 2023. Patients that died during their initial admission were excluded. OUTCOME MEASURES AND COMPARISONS/UNASSIGNED:Patient demographics, hospital quality measures, outcomes and readmission within 30-days following discharge for each patient were reviewed. 30-day readmission reason was recorded and correlation analysis was performed. RESULTS:A total of 3,032 patients were identified with a mean age of 82.1 years and 70.5% of patients being female. The 30-day readmission cohort was 2.6 years older (p<0.001) and 8.8% more male patients (p=0.027), had 0.5 higher CCI (p<0.001), 0.3 higher ASA class (p<0.001) and were 9.2% less independent at the time of admission (p= 0.003). Hemiarthroplasty procedure (32.7% vs. 24.1%) was associated with higher 30-day readmission compared to closed percutaneous screw fixation (4.5% vs. 8.8%) and cephalomedullary nail fixation (52.2% vs. 54.4%, p<0.001). Those readmitted by 30-days developed more major (16.7% vs. 8.0%) (p<0.001) and minor (50.5% vs. 36.4%) (p<0.001) complications during their initial hospitalization and had a 1.5 day longer LOS during their first admission (p<0.001). Those discharged home were less likely to be readmitted within 30-days (20.7% vs. 27.6%, (p=0.008). Multivariate regression revealed increasing ASA class (O.R. 1.47, p=0.002) and pre-injury ambulatory status (O.R. 1.42, p=0.007) were most associated with increased 30-day readmission. The most common reason for readmission was pulmonary complications (17.1% of complications) including acute respiratory failure, COPD exacerbation and pneumonia. CONCLUSION/CONCLUSIONS:Thirty-day readmission following hip fracture was associated with older, sicker patients with decreased pre-injury ambulation status. Hemiarthroplasty for femoral neck fracture was also associated with readmission. The most common reason for 30-day readmission following hip fracture was pulmonary complications. LEVEL OF EVIDENCE/METHODS:Prognostic Level III.

Aging populations worldwide face an increasing burden of age-related chronic conditions, necessitating a deeper understanding of the underlying mechanisms. Purine metabolism has emerged as a crucial player in the pathophysiology of aging, affecting various tissues and organs. Dysregulation of purine metabolism, particularly alterations in extracellular adenosine levels and adenosine receptor signaling, contributes to age-related musculoskeletal problems, cardiovascular diseases, inflammation, and impaired immune responses. Changes in purine metabolism are associated with diminished tissue repair and regeneration, altered bone density, and impaired muscle regeneration. Mechanistically, age-related alterations in purine metabolism involve reductions in extracellular adenosine production, impaired autocrine signaling, and dysregulated expression of CD73 and CD39. Targeting adenosine receptors, such as A_2A and A_2B receptors, emerges as a promising therapeutic approach to mitigate age-related conditions, including sarcopenia, obesity, osteoarthritis, and impaired wound healing. Since we cannot reverse time, understanding the intricate molecular interplay between purine metabolism and aging-related pathologies holds significant potential for developing novel therapeutic strategies to improve the health and quality of life of aging populations. In this review, we compile the findings related to purine metabolism during aging in several tissues and organs and provide insights into how these signals can be manipulated to circumvent the deleterious effects of the passage of time on our body.