What is the optimal management of a loose glenoid component after anatomic total shoulder arthroplasty: a systematic review.

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.

Factors associated with success of ream-and-run arthroplasty at a minimum of 5 years.

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.

Predictors of success following single-stage revision shoulder arthroplasty: results at a mean of five year follow-up in one hundred and twelve 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.

What Is the Survivorship After Hip Arthroscopy for Femoroacetabular Impingement? A Large-database Study.

BACKGROUND: Patients with femoroacetabular impingement (FAI) may experience lasting clinical improvement after hip arthroscopy; however, some patients will still eventually undergo early conversion to THA due to unresolved symptoms and progression of arthritis. However, the risk of this has been only incompletely characterized in prior studies. QUESTIONS/PURPOSES: Using a large healthcare claims database over a 5-year period (2011-2016), we asked: (1) What is the survivorship free from THA after arthroscopic osteoplasty performed for FAI? (2) What identifiable demographic factors and patient characteristics are associated with early conversion to THA after hip arthroscopy performed for FAI? METHODS: We included all patients who underwent hip arthroscopy for FAI, between the ages of 12 years and 63 years, with 3 months of claims data before hip arthroscopy and minimum 2-year follow-up. A total of 4730 hip arthroscopy patients from 2011 to 2014 were retrieved from a US commercial claims database. Hip arthroscopy incidence doubled over time from 1.2 to 2.1 persons per 100,000. Temporal trends, patient demographics, diagnoses at time of arthroscopy, and patient comorbidities were retrieved and logistic regression performed. Survivorship analysis on 11,323 patients (lifting the 2-year follow-up requirement) was also performed to identify independent variables associated with early risk of conversion to THA. RESULTS: In patients undergoing hip arthroscopy for FAI, the overall proportion of conversion to THA within 2 years after hip arthroscopy was 7% (338 of 4730). After controlling for confounding variables such as sex, obesity, and depression, we found the following were independently associated with increased odds of conversion to THA: older age (odds ratio 1.08 [95% CI 1.01 to 1.10]; p < 0.001), osteoarthritis (OR 2.91 [95% CI 2.27 to 3.77]; p < 0.001), joint inflammation (OR 1.89 [95% CI 1.16 to 3.09]; p = 0.01), and a history of opioid use (OR 2.17 [95% CI 1.69 to 2.79]; p < 0.001). Survivorship analysis similarly revealed that older age (hazard ratio 1.08 [95% CI 1.07 to 1.09]; p < 0.001), osteoarthritis (HR 2.53 [95% CI 2.13 to 3.01]; p < 0.001), joint inflammation (HR 1.53 [95% CI 1.10 to 2.11]; p = 0.01), a history of opioid use (HR 2.02 [95% CI 1.71 to 2.38]; p < 0.001), and smoking (HR 1.55 [95% CI 1.14 to 2.11]; p = 0.005), were independently associated with increased odds of conversion to THA within 2 years after hip arthroscopy for FAI. CONCLUSIONS: Although the findings of this study are limited and should not be taken in isolation, patients with FAI who are older, carry diagnoses of inflammatory or degenerative articular disease, or who use opioids or smoke should be counseled about a potentially increased risk of undergoing early conversion to THA after hip arthroscopy. Future studies to further examine the effect of these diagnoses in prospectively collected cohorts, incorporating radiographic and patient-reported outcome measures, are needed. LEVEL OF EVIDENCE: Level III, prognostic study.

Long-Term Mortality Trends After Revision Total Knee Arthroplasty.

BACKGROUND: Long-term mortality following primary total knee arthroplasty (TKA) is lower than the general population. However, it is unknown whether this is true in the setting of revision TKA. We examined long-term mortality trends following revision TKA. METHODS: This retrospective study included 4907 patients who underwent 1 or more revision TKA between 1985 and 2015. Patients were grouped by surgical indications and followed until death or October 2017. The observed number of deaths was compared to the expected number of deaths using standardized mortality ratios (SMR) and Poisson regression models. RESULTS: Compared to the general population, patients who underwent revision TKA for infection (SMR, 1.45; 95% confidence interval [CI], 1.33-1.57; P < .0001) and fracture (SMR, 1.16; 95% CI, 1.00-1.34; P = .04) experienced a significantly higher mortality risk. Patients who underwent revision TKA for infection and fracture experienced excess mortality soon after surgery which became more pronounced over time. In contrast, the mortality risk among patients who underwent revision TKA for loosening and/or bearing wear was similar to the general population (SMR, 0.95; 95% CI, 0.89-1.02; P = .16). Aseptic loosening and/or wear and instability patients had improved mortality initially; however, there was a shift to excess mortality beyond 5 years among instability patients, and beyond 10 years among aseptic loosening and/or wear patients. CONCLUSION: Mortality is elevated soon after revision TKA for infection and fracture. Mortality is lower than the general population after revision TKA for loosening and/or bearing wear but gets worse than the general population beyond the first postoperative decade.

Intra-articular injection of a substance P inhibitor affects gene expression in a joint contracture model.

Substance P (SP), a neurotransmitter released after injury, has been linked to deregulated tissue repair and fibrosis in musculoskeletal tissues and other organs. Although SP inhibition is an effective treatment for nausea, it has not been previously considered as an anti-fibrotic therapy. Although there are extensive medical records of individuals who have used SP antagonists, our analysis of human registry data revealed that patients receiving these antagonists and arthroplasty are exceedingly rare, thus precluding a clinical evaluation of their potential effects in the context of arthrofibrosis. Therefore, we pursued in vivo studies to assess the effect of SP inhibition early after injury on pro-fibrotic gene expression and contractures in an animal model of post-traumatic joint stiffening. Skeletally mature rabbits (n = 24) underwent surgically induced severe joint contracture, while injected with either fosaprepitant (a selective SP antagonist) or saline (control) early after surgery (3, 6, 12, and 24 h). Biomechanical testing revealed that differences in mean contracture angles between the groups were not statistically significant (P = 0.27), suggesting that the drug neither mitigates nor exacerbates joint contracture. However, microarray gene expression analysis revealed that mRNA levels for proteins related to cell signaling, pro-angiogenic, pro-inflammatory, and collagen matrix production were significantly different between control and fosaprepitant treated rabbits (P < 0.05). Hence, our study demonstrates that inhibition of SP alters expression of pro-fibrotic genes in vivo. This finding will motivate future studies to optimize interventions that target SP to reduce the formation of post-traumatic joint contractures.

Perioperative Inpatient Use of Selective Serotonin Reuptake Inhibitors Is Associated With a Reduced Risk of THA and TKA Revision.

BACKGROUND: Depression is common in the general population, and so it is likewise common among patients undergoing THA and TKA. Depression is associated with lower perioperative patient-reported outcomes and an increased risk of postoperative complications. Antidepressants are effective in managing symptoms of depression and may potentially contribute to better functional status and better clinical outcomes after THA and TKA. QUESTIONS/PURPOSES: We examined (1) whether perioperative depression is associated with all-cause revisions, revisions for aseptic loosening, revisions without infection, and periprosthetic joint infections (PJIs) in patients undergoing THA and TKA; and (2) whether perioperative antidepressant use reduces the risk of all-cause revisions, revisions for aseptic loosening, aseptic revisions, and PJIs in patients undergoing THA and TKA. METHODS: This was a retrospective study of adult patients (≥ 18 years) who underwent 20,112 primary and revision THAs and TKAs from January 1, 2002, through December 31, 2009, at a large US tertiary care hospital. Data on patient and surgery characteristics and outcomes (dates and types of revisions, death) were ascertained through the institutional joint registry. Perioperative antidepressant use was assessed by searching the daily medication administration records beginning at admission and ending at discharge. A diagnosis of depression was present in 4466 (22%), and antidepressants were administered at the time of 5077 (25%) surgical procedures. Multivariable Cox proportional hazard models were used to estimate associations between antidepressant use and the risk of all-cause revisions, revisions for aseptic loosening, aseptic revisions, and PJIs. RESULTS: Depression was associated with an increased risk of all-cause revisions (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.42-2.02; p < 0.001) and PJIs (HR, 2.23; 95% CI, 1.53-3.17; p < 0.001). Overall, perioperative antidepressant use was not associated with the risk of revision or PJI, but selective serotonin reuptake inhibitor (SSRI) users had a lower risk of all-cause revisions (HR, 0.77; 95% CI, 0.61-0.96; p = 0.001) and aseptic revisions (HR, 0.72; 95% CI, 0.56-0.93; p = 0.013). CONCLUSIONS: The presence of a depression diagnosis confers an increased risk of revision and PJI among patients undergoing THA and TKA, yet the risk is lower within the subset of patients who received SSRIs during the perioperative period. Future longitudinal studies with detailed antidepressant medication histories are warranted to better understand the potential biologic effects of SSRI on the risk of revision in patients undergoing THA and TKA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Long-term Mortality After Revision THA.

BACKGROUND: Long-term mortality after primary THA is lower than in the general population, but it is unknown whether this is also true after revision THA. QUESTIONS/PURPOSES: We examined (1) long-term mortality according to reasons for revision after revision THA, and (2) relative mortality trends by age at surgery, years since surgery, and calendar year of surgery. METHODS: This retrospective study included 5417 revision THAs performed in 4532 patients at a tertiary center between 1969 and 2011. Revision THAs were grouped by surgical indication in three categories: periprosthetic joint infections (938; 17%); fractures (646; 12%); and loosening, bearing wear, or dislocation (3833; 71%). Patients were followed up until death or December 31, 2016. The observed number of deaths in the revision THA cohort was compared with the expected number of deaths using standardized mortality ratios (SMRs) and Poisson regression models. The expected number of deaths was calculated assuming that the study cohort had the same calendar year, age, and sex-specific mortality rates as the United States general population. RESULTS: The overall age- and sex-adjusted mortality was slightly higher than the general population mortality (SMR, 1.09; 95% CI, 1.05-1.13; p < 0.001). There were significant differences across the three surgical indication subgroups. Compared with the general population mortality, patients who underwent revision THA for infection (SMR, 1.35; 95% CI, 1.24-1.48; p < 0.001) and fractures (SMR, 1.23; 95% CI, 1.11-1.37; p < 0.001) had significantly increased risk of death. Patients who underwent revision THA for aseptic loosening, wear, or dislocation had a mortality risk similar to that of the general population (SMR, 1.01; 95% CI, 0.96-1.06; p = 0.647). The relative mortality risk was highest in younger patients and declined with increasing age at surgery. Although the relative mortality risk among patients with aseptic indications was lower than that of the general population during the first year of surgery, the risk increased with time and got worse than that of the general population after approximately 8 to 10 years after surgery. Relative mortality risk improved with time after revision THA for aseptic loosening, wear, or dislocation. CONCLUSIONS: Shifting mortality patterns several years after surgery and the excess mortality after revision THA for periprosthetic joint infections and fractures reinforce the need for long-term followup, not only for implant survival but overall health of patients having THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

Efficacy of a Four-Hour Drainage Clamping Technique in the Reduction of Blood Loss Following Total Hip Arthroplasty: A Prospective Cohort Study.

BACKGROUND During total hip arthroplasty (THA) drainage is used by most surgeons. However, the optimal drainage strategy remains controversial. The aim of this prospective cohort study was to determine the safety and efficacy of a four-hour drainage clamping technique in patients undergoing THA. MATERIAL AND METHODS There were 64 patients who underwent THA from March 2012 to December 2015 who were enrolled in the study; 32 patients were randomly assigned to four hours of a drainage clamping technique (clamping group); 32 patients were treated with a non-clamping drainage technique (non-clamping group). All perioperative clinical details were recorded for comparative analysis. RESULTS The postoperative drainage volume and calculated blood loss were significantly greater in the drainage non-clamping group, p<0.001 and p=0.028, respectively. Significantly more patients in the drainage non-clamping group required a blood transfusion, seven cases versus one case (p=0.023). Significantly more units of blood were transfused in the drainage non-clamping group (p=0.001). No significant differences were found for all other clinical outcome factors. CONCLUSIONS The four-hour drainage clamping technique following THA, compared with drainage non-clamping technique reduced blood loss and requirement for blood transfusion. There was no increase in adverse clinical events using the four-hour drainage clamping method. Therefore, four-hour drainage clamping has the potential for routine use in THA.

Patient-Reported Outcomes Can Be Used to Streamline Post-Total Hip Arthroplasty Follow-Up to High-Risk Patients.

BACKGROUND: Patient-reported outcomes are increasingly used to capture the patients' perspective in total hip arthroplasty (THA). They can potentially be used to streamline post-THA follow-up to high-risk patients. We aimed to determine whether the long-term revision risk in THA relates to patient-reported measures at 2 and 5 years. METHODS: In a single-institution cohort of primary THA procedures, we examined the association between 2-year and 5-year pain and Mayo Hip Scores and the risk of revision. RESULTS: The absolute scores at 2 and 5 years were both significantly associated with the risk of revisions. Every 10-unit decline in the 2-year Mayo Hip Score <60 was associated with a significant 50% increase in the risk of revision (hazard ratio, 1.5 per 10 units; 95% confidence interval, 1.3-1.8). Similarly, every 10-unit decline in the 5-year Mayo Hip Score <60 was associated with almost doubling of the risk of revision (hazard ratio, 1.9 per 10 units; 95% confidence interval, 1.7-2.1). CONCLUSION: We conclude that patient-reported outcomes in THA have prognostic importance and can be taken into account when planning frequency of aftercare. This will improve the efficiency of follow-up in large registry-based follow-up efforts.

Current Concepts Review: Large Language Models in Orthopaedics: Definitions, Uses, and Limitations.

➤ 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.

Risk Factors for Stiffness Requiring Intervention After Ream-and-Run Arthroplasty.

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: 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: 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: 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: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Oral and IV Antibiotic Administration After Single-Stage Revision Shoulder Arthroplasty: Study of Survivorship and Patient-Reported Outcomes in Patients without Clear Preoperative or Intraoperative Infection.

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.

Association Between Serum Testosterone Levels and Cutibacterium Skin Load in Patients Undergoing Elective Shoulder Arthroplasty: A Cohort Study.

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: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Direct Inpatient Medical Costs of Operative Treatment of Periprosthetic Hip and Knee Infections Are Twofold Higher Than Those of Aseptic Revisions.

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: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Surface Roughness of Titanium Orthopedic Implants Alters the Biological Phenotype of Human Mesenchymal Stromal Cells.

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.

The Use and Adverse Effects of Oral and Intravenous Antibiotic Administration for Suspected Infection After Revision Shoulder Arthroplasty.

BACKGROUND: When performing revision shoulder arthroplasty, surgeons do not have access to the results of intraoperative culture specimens and will administer empiric antibiotics to cover for the possibility of deep infection until the culture results are finalized. The purpose of this study was to report the factors associated with the initiation, modification, and adverse events of 2 different postoperative antibiotic protocols in a series of revision shoulder arthroplasties. METHODS: In this study, 175 patients undergoing revision shoulder arthroplasty were treated with either a protocol of intravenous (IV) antibiotics if there was a high index of suspicion for infection or a protocol of oral antibiotics if the index of suspicion was low. Antibiotics were withdrawn if cultures were negative and were modified as indicated if the cultures were positive. Antibiotic course, modification, and adverse effects to antibiotic administration were documented. RESULTS: On univariate analysis, factors significantly associated with the initiation of IV antibiotics were male sex (p < 0.001), history of infection (p < 0.001), intraoperative humeral loosening (p = 0.003), and membrane formation (p < 0.001). On multivariate analysis, male sex (p = 0.003), history of infection (p = 0.003), and membrane formation (p < 0.001) were found to be independent predictors of the initiation of IV antibiotics. On the basis of preoperative and intraoperative characteristics, surgeons anticipated the culture results in 75% of cases, and modification of antibiotic therapy was required in 25%. The modification from oral to IV antibiotics due to positive culture results was made significantly more often in male patients (p < 0.001). Adverse effects of antibiotic administration occurred in 19% of patients. The rates of complications were significantly lower in the patients treated with oral antibiotics and a shorter course of antibiotics (p < 0.001). CONCLUSIONS: Complications associated with antibiotic administration after revision shoulder arthroplasty are not infrequent and are more common in patients whose initial protocol is IV antibiotics. Further study is needed to balance the effectiveness and risks of post-revision antibiotic treatment given the frequency of antibiotic-related complications. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Challenges in the Measurement and Interpretation of Serum Titanium Concentrations.

The measurement of circulating metal ion levels in total hip arthroplasty patients continues to be an area of clinical interest. National regulatory agencies have recommended measurement of circulating cobalt and chromium concentrations in metal-on-metal bearing symptomatic total hip arthroplasty patients. However, the clinical utility of serum titanium (Ti) measurements is less understood due to wide variations in reported values and methodology. Fine-scale instrumentation for detecting in situ Ti levels continues to improve and has transitioned from graphite furnace atomic absorption spectroscopy to inductively coupled plasma optical emission spectrometry or inductively coupled plasma mass spectrometry. Additionally, analytical interferences, variable sample types, and non-standardized sample collection methods complicate Ti measurement and underlie the wide variation in reported levels. Normal reference ranges and pathologic ranges for Ti levels remain to be established quantitatively. However, before these ranges can be recognized and implemented, methodological standardization is necessary. This paper aims to provide background and recommendations regarding the complexities of measurement and interpretation of circulating Ti levels in total hip arthroplasty patients.

Weight changes after total knee arthroplasty in Chinese patients: a matched cohort study regarding predictors and outcomes.

BACKGROUND: The purpose of this study was to compare 2-year BMI changes between patients undergoing simultaneous bilateral total knee arthroplasty (TKA), staged bilateral TKA, and unilateral TKA. We also sought to determine the predictors of weight change and whether clinically meaningful weight changes affected outcomes. PATIENTS AND METHODS: This retrospective, single-institution study included 202 Chinese patients who received simultaneously bilateral TKA, staged bilateral TKA, or unilateral TKA from 2008 to 2015. There were 49 simultaneous bilateral TKAs, 52 staged bilateral TKAs, and a matched 101 unilateral TKAs. RESULTS: 66.8% (135/202) of patients lost weight after TKA surgery. However, 20.7% (42/202) of patients experienced clinically meaningful weight loss (a BMI decrease of more than 5%). Paired t test showed that 2-year BMI was significantly lower than preoperative BMI (p < 0.001). Weight loss was significantly different between the surgical strategy (p < 0.001). Preoperative BMI and age were predictive of clinically significant weight loss or gain (p < 0.05). Multiple linear regression showed that post-operative weight loss was associated with better Western Ontario and McMaster Universities Osteoarthritis Index and SF-36 scores (p < 0.001). CONCLUSION: Patients after TKA experience weight loss. Age and preoperative BMI predict clinically meaningful weight change. Simultaneous bilateral TKA is associated with higher likelihood of weight loss. Clinically meaningful weight loss experiences better patient-reported outcomes.

In vivo assessment of high-molecular-weight polyethylene core suture tape for intra-articular ligament reconstruction: an animal study.

AIMS: Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. MATERIALS AND METHODS: A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6). RESULTS: At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected. CONCLUSION: Our results indicate that FiberTape increases the biomechanical performance of intra-articular ligament reconstructions in a verified rabbit model at eight weeks. Within this period, FiberTape did not adversely affect bone tunnel healing or invoke a prolonged elevation in inflammation. Cite this article: Bone Joint J 2019;101-B:1238-1247.