Faculty Bibliography

➤ Large language models are a subset of artificial intelligence. Large language models are powerful tools that excel in natural language text processing and generation.➤ There are many potential clinical, research, and educational applications of large language models in orthopaedics, but the development of these applications needs to be focused on patient safety and the maintenance of high standards.➤ There are numerous methodological, ethical, and regulatory concerns with regard to the use of large language models. Orthopaedic surgeons need to be aware of the controversies and advocate for an alignment of these models with patient and caregiver priorities.

BACKGROUND:Ream-and-run arthroplasty offers improvements in shoulder pain and function for patients with primary glenohumeral arthritis who wish to avoid limitations associated with a polyethylene glenoid component. Longer-term clinical outcome assessments of the ream-and-run procedure are sparse in the literature. This study aimed to present minimum 5-year functional outcomes in a large cohort following ream-and-run arthroplasty to determine factors associated with clinical success and reoperation. METHODS:Patients who underwent ream-and-run surgery with a minimum of 5 years of follow-up were identified through a retrospective review of a prospectively maintained database from a single academic institution. To assess clinical outcomes, the Simple Shoulder Test (SST) was administered and assessed to determine achievement of the minimal clinically important difference, as well as the necessity for open revision surgery. Factors associated with P < .1 on univariate analysis were included in multivariate analysis. RESULTS:Of 228 patients who consented to undergo long-term follow-up, 201 (88%) were included in our analysis (mean follow-up period, 7.6 ± 2.1 years). The average age was 59.4 ± 8.8 years, and 93% of patients were men. The majority of patients had a diagnosis of osteoarthritis (79%) or capsulorrhaphy arthropathy (10%). SST scores improved from a mean of 4.9 ± 2.5 preoperatively to a mean of 10.2 ± 2.6 at latest follow-up. The minimal clinically important difference in the SST score of 2.6 was reached by 165 patients (82%). Male sex (P = .020), nondiabetic status (P = .080), and lower preoperative SST score (P < .001) were included in a multivariate analysis. Male sex (P = .010) and lower preoperative SST score (P < .001) were associated with clinically important improvements in SST scores on multivariate analysis. Open revision surgery was required in 22 patients (11%). Younger age (P < .001), female sex (P = .055), and higher preoperative pain score (P = .023) were included in a multivariate analysis. Only younger age was predictive of open revision surgery (P = .003). CONCLUSIONS:Ream-and-run arthroplasty can provide significant and clinically important improvements in clinical outcomes at minimum 5-year follow-up. Successful clinical outcomes were significantly associated with male sex and lower preoperative SST scores. Reoperation was more common in younger patients.

PURPOSE:The objective was to determine factors associated with a successful outcome at a minimum of two years after revision of a failed shoulder arthroplasty. METHODS:We conducted a retrospective study of revision shoulder arthroplasties performed over a ten year period and collected patient-reported outcome data and re-revision data. A successful outcome was defined by improvement greater than the minimal clinically important difference (MCID) for the Simple Shoulder Test (SST). RESULTS:One hundred twelve patients with average follow-up of five years were included. Improvement of VAS pain scores (6.6 ± 2.3 to 2.9 ± 2.6) and SST scores (2.7 ± 2.6 to 6.6 ± 3.3) were significant (p < 0.001). Males were more likely to have a successful outcome than females (p = 0.01). CONCLUSION:Two-thirds of patients experienced clinically significant improvement at a minimum of two years after revision shoulder arthroplasty. Male sex was the strongest independent predictor of a successful outcome.

BACKGROUND:Total shoulder arthroplasty (TSA) provides excellent long-term clinical outcomes in the treatment of glenohumeral arthritis. However, symptomatic glenoid polyethylene loosening can be seen at intermediate follow-up and can lead to shoulder pain and dysfunction. The purpose of this study was to perform a systematic review of the available literature to determine the optimal management of symptomatic glenoid loosening with regard to reoperation and patient satisfaction following various approaches to symptomatic glenoid loosening. METHODS:This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies investigating revision arthroplasty for the treatment of glenoid loosening with clinical outcomes were identified. Clinical failure was defined as a repeat procedure after revision arthroplasty. RESULTS:Overall, 14 studies met inclusion criteria that included 483 patients with a mean age of 66.5 ± 3.0 years who underwent revision arthroplasty for symptomatic glenoid loosening. There were 8 studies that discussed conversion to a hemiarthroplasty (HA, 148 patients), 7 studies that discussed glenoid reimplantation in a single setting (1-stage TSA, 157 patients), 2 studies that discussed glenoid reimplantation in a staged setting (2-stage TSA, 18 patients), and 2 studies that discussed conversion to a reverse shoulder arthroplasty (RSA, 164 patients). All patients underwent glenoid component removal. The length of follow-up was significantly shorter in the RSA group (41 months for RSA vs. 56 months for HA vs. 55 months for 1-stage TSA vs. 62 months for 2-stage TSA, P < .001). The reoperation rate at the final follow-up was 19% for the HA cohort, 20% for the 1-stage TSA cohort, 22% for the 2-stage TSA cohort, and 21% for the RSA cohort (P = .971). Patient satisfaction rate at the final follow-up was 62% for the HA cohort, 66% for the 1-stage TSA cohort, 71% for the 2-stage TSA cohort, and 86% for the RSA cohort (P = .045). Positive cultures were noted in 15% of patients with Cutibacterium acnes comprising 72% of positive cultures. CONCLUSIONS:Overall, the optimal management of symptomatic glenoid loosening remains unclear. All 4 types of revision arthroplasty (HA, 1-stage TSA, 2-stage TSA, and RSA) had a similar reoperation rate (20%) at the latest follow-up. Conversion to RSA provided a higher proportion of patients satisfied with the procedure. However, the length of follow-up was significantly shorter than other groups, and therefore longer-term follow-up of this group is needed to determine if results are durable.

UNLABELLED:Ream-and-run arthroplasty can improve pain and function in patients with glenohumeral arthritis while avoiding the complications and activity restrictions associated with a prosthetic glenoid component. However, stiffness is a known complication after ream-and-run arthroplasty and can lead to repeat procedures such as a manipulation under anesthesia (MUA) or open surgical revision. The objective of this study was to determine risk factors associated with repeat procedures indicated for postoperative stiffness after ream-and-run arthroplasty. METHODS/UNASSIGNED:We conducted a retrospective review of our shoulder arthroplasty database to identify patients who underwent ream-and-run arthroplasty and determined which patients underwent subsequent repeat procedures (MUA and/or open revision) indicated for postoperative stiffness. The minimum follow-up was 2 years. We collected baseline demographic information and preoperative and 2-year patient-reported outcome scores and analyzed preoperative radiographs. Univariate and multivariate analyses determined the factors significantly associated with repeat procedures to treat postoperative stiffness. RESULTS/UNASSIGNED:There were 340 patients who underwent ream-and-run arthroplasty. The mean Simple Shoulder Test (SST) scores for all patients improved from 5.0 ± 2.4 preoperatively to 10.2 ± 2.6 postoperatively (p < 0.001). Twenty-six patients (7.6%) underwent open revision for stiffness. An additional 35 patients (10.3%) underwent MUA. Univariate analysis found younger age (p = 0.001), female sex (p = 0.034), lower American Society of Anesthesiologists (ASA) class (p = 0.045), posterior decentering on preoperative radiographs (p = 0.010), and less passive forward elevation at the time of discharge after ream-and-run arthroplasty (p < 0.001) to be significant risk factors for repeat procedures. Multivariate analysis found younger age (p = 0.040), ASA class 1 compared with class 3 (p = 0.020), and less passive forward elevation at discharge (p < 0.001) to be independent risk factors for repeat procedures. Of the patients who underwent open revision for stiffness, 69.2% had multiple positive cultures for Cutibacterium. CONCLUSIONS/UNASSIGNED:Younger age, ASA class 1 compared with class 3, and less passive forward elevation in the immediate postoperative period were independent risk factors for repeat procedures to treat postoperative stiffness after ream-and-run arthroplasty. LEVEL OF EVIDENCE/UNASSIGNED:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Following revision shoulder arthroplasty, postoperative antibiotics are selected before the results of intraoperative cultures become available. We determined infection-free survival, revision-free survival, complications, and patient-reported outcomes for patients selected to receive oral or intravenous (IV) antibiotics after revision arthroplasty. METHODS:This study included 92 patients who had revision shoulder arthroplasty. IV antibiotics were administered if the surgeon had a high index of suspicion for infection, and oral antibiotics were given if there was a low suspicion. Antibiotic therapy was modified based on intraoperative culture results. Patient-reported outcomes and adverse events were documented at a mean of 4.1 years. RESULTS:In selecting antibiotic therapy, surgeons correctly predicted the presence or absence of multiple positive cultures of specimens from the revision surgery in 72% of the 92 cases. Subsequent re-revision surgery was required in 17 (18%) of the patients; 8 of these 17 patients had ≥2 positive cultures at re-revision. Patients who initially received IV antibiotics and those who initially received oral antibiotics had similar revision-free (p = 0.202) and infection-free (p = 0.155) survivorship. Patients requiring a change from oral to IV antibiotics based on positive cultures had similar survivorship compared with those initially treated with IV antibiotics. The IV and oral antibiotic groups had similar postoperative Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES), and satisfaction scores. Patients receiving IV antibiotics had a higher rate of antibiotic-related adverse events. CONCLUSIONS:Post-revision antibiotic therapy was associated with an infection-free survival rate of 91% at a mean of >4 years of follow-up. Infection-free survival, revision-free survival, and patient-reported outcomes were similar in high-risk patients placed on IV antibiotics and low-risk patients placed on oral antibiotics. Further study is needed to define the indications for IV or oral antibiotics after revision arthroplasty. LEVEL OF EVIDENCE:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

UNLABELLED:Cutibacterium periprosthetic joint infections are important complications of shoulder arthroplasty. Although it is known that these infections are more common among men and that they are more common in patients with high levels of Cutibacterium on the skin, the possible relationship between serum testosterone levels and skin Cutibacterium levels has not been investigated. METHODS:In 51 patients undergoing shoulder arthroplasties, total serum testosterone, free testosterone, and sex hormone binding globulin levels obtained in the clinic before the surgical procedure were compared with the levels of Cutibacterium on the skin in clinic, on the skin in the operating room prior to the surgical procedure, and on the dermal wound edge of the incised skin during the surgical procedure. RESULTS:Clinic skin Cutibacterium loads were strongly associated with both clinic free testosterone levels (tau, 0.569; p < 0.001) and total serum testosterone levels (tau, 0.591; p < 0.001). The prepreparation skin and wound Cutibacterium levels at the time of the surgical procedure were also significantly associated with both the clinic total serum testosterone levels (p < 0.001) and the clinic free testosterone levels (p < 0.03). A multivariate analysis demonstrated that serum testosterone was an independent predictor of high skin Cutibacterium loads, even when age and sex were taken into account. Patients taking supplemental testosterone had higher free testosterone levels and tended to have higher skin Cutibacterium loads. Patients who underwent the ream-and-run procedure had higher total and free testosterone levels and higher skin Cutibacterium loads. CONCLUSIONS:Testosterone levels are predictive of skin Cutibacterium levels in patients undergoing shoulder arthroplasty. This relationship deserves further investigation both as a risk stratification tool and as a potential area for intervention in reducing shoulder periprosthetic joint infection. LEVEL OF EVIDENCE/METHODS:Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT:The Allen and Ferguson classification of cervical spine injuries is widely used. They described compressive Extension (CE) injuries as having five progressive stages. Stage 4(CE4) and 5(CE5) have been described as having a posterior vertebral arch fracture involving two motion segments accompanied by displacement (dislocation) of the vertebral body at a single level. However, in their original work, CE4 was described only as a hypothetical stage, while CE5 was found in only three patients. Beyond this, little is understood about these injuries. PURPOSE:To identify characteristics of compression extension injuries with vertebral body displacement (CE4 and CE5) from a series of surgically treated subaxial cervical spine fractures. A secondary aim was to identify specific characteristics that may guide treatment or affect prognosis. DESIGN:Retrospective case series. PATIENT SAMPLE:Twenty-four patients who underwent surgical stabilization of CE4 and CE5 cervical spine fracture-dislocations in non-ankylosed spines over a 14-year period. OUTCOME MEASURES:Radiographic categorization of CE injury type, treatment rendered, postoperative spinal alignment, presence of nonunion, loss of fixation, hardware-related and neurologic complications. METHODS:After IRB approval, patients with CE injuries were identified through billing data and radiology records at a level I trauma center between January 2005 and September 2018. Demographic data, ISS, ASA, motor score, and complications during the hospitalization were collected from the patient's EMR. CT scans were reviewed to assess fracture pattern, level, and location of the vertebral arch fracture, vertebral body displacement, spinal canal diameter and method of surgical stabilization. Injuries were classified according to the classification of Allen and Ferguson, and the AO subaxial cervical spine classification. RESULTS:Of 221 patients identified with CE mechanism, 24 had CE4 or CE5 injuries. High-energy mechanism occurred in 92% of the patients, with motor vehicle accidents being the most common. The average ASIA motor score was 80 preoperatively and 84 at average 398 days follow-up. All CE4 and CE5 injuries occurred at C6-C7 or C7-T1. Average anterolisthesis was 6.26 mm (SD ± 2.3 mm) for CE4 and 16.8 mm (SD ± 1.8 mm) for CE5. Average spinal canal diameter at the level of dislocation was 20 mm (SD ± 0.4 mm) for CE4 and 30.5 mm (range 29.6 - 31.4 mm) for CE5. The surgical approach was anterior in 5 patients, posterior in 12 patients, and combined in 7 patients. Four patients had single-evel fixation, all of whom had CE4 injuries, and 20 patients had fixation across two or more levels. Thirty percent of patients had complications, none of which included postoperative spinal malalignment, nonunion or hardware-related complications, or worsening of neurologic exam. Three deaths occurred in the postoperative hospitalization period (7 to 15 days). CONCLUSION:CE4 and CE5 injuries represented 10% and 1% of all CE injuries in our series respectively occurring only at the C6-C7 and C7-T1 levels. Though by original description these are two-level injuries, in patients with milder posterior element injury, single level stabilization was used successfully. We have therefore proposed designating CE4 into less severe CE4a and more severe CE4b injuries. Because this fracture pattern typically results in widening of the spinal canal as the anterior displacement of the vertebral body occurs independent of the fractured posterior elements, spinal cord injuries are neither as severe nor as common as in fracture-dislocation from other mechanisms.

BACKGROUND:Periprosthetic joint infections (PJIs) following total hip arthroplasty (THA) and total knee arthroplasty (TKA) are associated with substantial morbidity. A better understanding of the costs of PJI treatment can inform prevention, treatment, and reimbursement strategies. The purpose of the present study was to describe direct inpatient medical costs associated with the treatment of hip and knee PJI. METHODS:At a single tertiary care institution, 176 hips and 266 knees that underwent 2-stage revisions for the treatment of PJI from 2009 to 2015 were compared with 1,611 hips and 1,276 knees that underwent revisions for aseptic indications. In addition, 84 hips and 137 knees that underwent irrigation and debridement (I&D) with partial component exchange were compared with 39 hips and 138 knees that underwent partial component exchange for aseptic indications. Line-item details of services billed during hospitalization were retrieved, and standardized direct medical costs were calculated in 2018 inflation-adjusted dollars. RESULTS:The mean direct medical cost of 2-stage revision THA performed for the treatment of PJI was significantly higher than that of aseptic revision THA ($58,369 compared with $22,846, p < 0.001). Similarly, the cost of 2-stage revision TKA performed for the treatment of PJI was significantly higher than that of aseptic revision TKA ($56,900 compared with $24,630, p < 0.001). Even when the total costs of aseptic revisions were doubled for a representative comparison with 2-stage procedures, the costs of PJI procedures were 15% to 28% higher than those of the doubled costs of aseptic revisions (p < 0.001). The mean direct medical cost of I&D procedures for PJI was about twofold higher than of partial component exchange for aseptic indications. CONCLUSIONS:The direct medical costs of operative treatment of PJI following THA and TKA are twofold higher than the costs of similar aseptic revisions. The high economic burden of PJI warrants efforts to reduce the incidence of PJI. Reimbursement schemes should account for the high costs of treating PJI in order to ensure sustainable patient care. LEVEL OF EVIDENCE/METHODS:Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Metal orthopedic implants are largely biocompatible and generally achieve long-term structural fixation. However, some orthopedic implants may loosen over time even in the absence of infection. In vivo fixation failure is multifactorial, but the fundamental biological defect is cellular dysfunction at the host-implant interface. Strategies to reduce the risk of short- and long-term loosening include surface modifications, implant metal alloy type, and adjuvant substances such as polymethylmethacrylate cement. Surface modifications (e.g., increased surface rugosity) can increase osseointegration and biological ingrowth of orthopedic implants. However, the localized responses of cells to implant surface modifications need to be better characterized. As an in vitro model for investigating cellular responses to metallic orthopedic implants, we cultured mesenchymal stromal/stem cells on clinical-grade titanium disks (Ti6Al4V) that differed in surface roughness as high (porous structured), medium (grit blasted), and low (bead blasted). Topological characterization of clinically relevant titanium (Ti) materials combined with differential mRNA expression analyses (RNA-seq and real-time quantitative polymerase chain reaction) revealed alterations to the biological phenotype of cells cultured on titanium structures that favor early extracellular matrix production and observable responses to oxidative stress and heavy metal stress. These results provide a descriptive model for the interpretation of cellular responses at the interface between native host tissues and three-dimensionally printed modular orthopedic implants, and will guide future studies aimed at increasing the long-term retention of such materials after total joint arthroplasty. Impact statement Using an in vitro model of implant-to-cell interactions by culturing mesenchymal stromal cells (MSCs) on clinically relevant titanium materials of varying topological roughness, we identified mRNA expression patterns consistent with early extracellular matrix (ECM) production and responses to oxidative/heavy metal stress. Implants with high surface roughness may delay the differentiation and ECM formation of MSCs and alter the expression of genes sensitive to reactive oxygen species and protein kinases. In combination with ongoing animal studies, these results will guide future studies aimed at increasing the long-term retention of widely used titanium materials after total joint arthroplasty.