Phase 1 study of the pharmacokinetics and clinical proof-of-concept activity of a biofilm-disrupting human monoclonal antibody in patients with chronic prosthetic joint infection of the knee or hip.

We report the results of a first-in-human phase 1 clinical study to evaluate TRL1068, a native human monoclonal antibody that disrupts bacterial biofilms with broad-spectrum activity against both Gram-positive and Gram-negative species. The study population consisted of patients with chronic periprosthetic joint infections (PJIs) of the knee or hip, including both monomicrobial and polymicrobial infections, that are highly resistant to antibiotics due to biofilm formation. TRL1068 was administered via a single pre-surgical intravenous infusion in three sequentially ascending dose groups (6, 15, and 30 mg/kg). Concomitant perioperative antibiotics were pathogen-targeted as prescribed by the treating physician. In this double-blinded study, 4 patients were randomized to receive placebo and 11 patients to receive TRL1068 on day 1, as well as targeted antibiotics for 7 days prior to the scheduled removal of the infected implant and placement of an antibiotic-eluting spacer as the first stage of the standard of care two-stage exchange arthroplasty. No adverse events attributable to TRL1068 were reported. TRL1068 serum half-life was 15-18 days. At day 8, the concentration in synovial fluid was approximately 60% of the blood level and thus at least 15-fold above the threshold for biofilm-disrupting activity in vitro. Explanted prostheses were sonicated to release adherent bacteria for culture, with elimination of the implant bacteria observed in 3 of the 11 patients who received TRL1068, which compares favorably to prior PJI treatments. None of the patients who received TRL1068 had a relapse of the original infection by the end of the study (day 169). CLINICAL TRIALS: This study is registered with ClinicalTrials.gov as NCT04763759.

Point-of-Care Coating of Revision Femoral Stems With Antibiotic-Loaded Calcium Sulfate: Reduction in Infection After 2nd Stage Reimplantation but Not With Aseptic Revisions.

Background: Infection rates in revision total hip arthroplasty are lower when antibiotic loaded cemented stems are utilized. Inspired by this technique, a point-of-care coating of antibiotic-loaded calcium sulfate (CaSO4) was applied to cementless revision stems in aseptic revision and 2nd stage reimplantation total hip arthroplasty. Methods: One hundred eleven consecutive femoral stems were coated. Just prior to insertion, 10 cc of CaSO4 was mixed with 1 g vancomycin and 240 mg tobramycin with the paste applied to the stem. The results were compared to a matched cohort (N = 104) performed across the previous 5 years. The surgical methods were comparable, but for the stem coating. The study group was followed for a minimum of 3 years. Results: In the study cohort of 111 patients, there were 69 aseptic revisions with one periprosthetic joint infection (PJI) (1.4%) and 42 second-stage reimplantations with 2 PJIs (4.8%). In the control cohort of 104 patients, there were 74 aseptic revisions with one PJI (1.4%) and 30 second-stage reimplantations with 7 PJIs (23.3%). There was no significant reduction in PJI rate in the aseptic revision subgroup (1.4% study vs 1.4% control group), P = 1.000. Antibiotic stem coating reduced PJI rate in the 2nd stage reimplantation subgroup (23.3% control vs 4.8% study group), P = .028. In both groups, there were no cases of aseptic stem loosening. Conclusions: Point-of-care antibiotic coating of cementless revision femoral stems reduces PJI infection rate in 2nd stage reimplantations only. We theorize that microbes persist in the endosteal cortices after resection and may contribute to infection recurrence.

Does-dual mobility still offer improved stability in smaller cup sizes? A computer modelling comparison of stability with 22-mm versus 28-mm inner heads in dual-mobility versus single-bearing constructs.

PURPOSE: Dislocation remains 1 of the leading causes of revision after primary total hip arthroplasty (THA) and there is clear evidence the dual-mobility (DM) is used more frequently to minimise this. But in smaller cups, whether the use of DM with smaller 22-mm heads imparts any increased stability compared to standard bearing is unknown; especially when those smaller cups now allow for large single-bearing (SB) heads. METHODS: 3 primary cup sizes (48 mm, 50 mm, 52 mm) were chosen a priori for modelling. Head sizes trialled for the standard bearing (SB) constructs group were 28-0 mm, 32-0 mm and 36-0 mm against neutral polyethylene liners. In the modular sub-hemispheric DM constructs the inner head sizes for the DM constructs were altered where appropriate (22-0 mm vs. 28-0 mm). Cup position, stem offset, and stem size were standardised. RESULTS: Both DM constructs outperformed all SB constructs because of a statistically significant jump distance increase (p < 0.001). However, there was no difference in range of motion (ROM) or jump distances between the 22-mm and 28-mm DM inner heads.The ROM angle before impingement between the DM (with 22-mm or 28-mm heads) and SB (with different head sizes where appropriate) showed no statistically significant difference. However, DM constructs presented significantly larger jump distances than SB constructs for both provocative dislocation tests across all 3 cup sizes.Of interest, for 50-mm and 52-mm cup sizes (for which this particular DM construct design can accommodate both 22-mm and 28-mm inner heads), there were no differences in ROM or jump distance between 22-mm versus 28-mm inner heads. CONCLUSIONS: In this computer-modelling study, DM constructs are advantageous over SB constructs for improving jump distances in clinically provocative positions, but not range of motion angles. Inner head diameter of DM has no effect on stability.

Prosthetic Limb Attachment via Electromagnetic Attraction through a Closed Skin Envelope.

OBJECTIVE: Current socket-based methods of prosthetic limb attachment are responsible for many of the dominant problems reported by persons with amputation. In this work, we introduce a new paradigm for attachment via electromagnetic attraction between a bone-anchored ferromagnetic implant and an external electromagnet. Our objective was to develop a design framework for electromagnetic attachment, and to evaluate this framework in the context of transfemoral amputation. METHODS: We first used inverse dynamics to calculate the forces required to suspend a knee-ankle-foot prosthesis during gait. We then conducted cadaveric dissections to inform implant geometry and design a surgical methodology for covering the implant. We also developed an in silico framework to investigate how electromagnet design affects system performance. Simulations were validated against benchtop testing of a custom-built electromagnet. RESULTS: The physical electromagnet matched simulations, with a root-mean-square percentage error of 4.2% between measured and predicted forces. Using this electromagnet, we estimate that suspension of a prosthesis during gait would require 33 W of average power. After 200 and 1000 steps of simulated walking, the temperature at the skin would increase 2.3℃ and 15.4℃ relative to ambient, respectively. CONCLUSION: Our design framework produced an implant and electromagnet that could feasibly suspend a knee-ankle-foot prosthesis during short walking bouts. Future work will focus on optimization of this system to reduce heating during longer bouts. SIGNIFICANCE: This work demonstrates the initial feasibility of an electromagnetic prosthetic attachment paradigm that has the potential to increase comfort and improve residual limb health for persons with amputation.

End-stage renal disease patients have comparable results to renal transplant patients after shoulder arthroplasty.

Background: End-stage renal disease (ESRD) and renal transplant (RT) patients are known to have more perioperative and postoperative complications after arthroplasty surgeries when compared to patients without. We hypothesize that RT patients undergoing shoulder arthroplasty (SA) have fewer systemic and surgical complications when compared to ESRD patients undergoing SA. Methods: This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had undergone primary total and reverse shoulder arthroplasty, respectively, and subsequent surgical revisions. Unadjusted univariate analysis of patient demographics, Charlson Cormorbidty Index, and surgical complications at 90 days, 1 year, and 2 years after was performed using chi-squared testing. Multivariate logistic regression analyses were subsequently performed for systemic complications and prosthesis outcomes at all time points. Results: Of 1191 patients with ESRD or previous RT and who underwent either total shoulder arthroplasty or reverse total shoulder arthroplasty, 1042 (87.5%) had ESRD and 149 (12.5%) had a previous RT. ESRD SA patients were more likely to have hypertension, liver disease, coronary artery disease, and hypothyroidism. Interestingly no statistical significance was found in multivariate analysis for systemic complications at 90 days, nor for surgical complications at the 90-day, 1-year, or 2-year mark between ESRD and RT cohorts. Conclusion: SAs have comparable outcomes in ESRD and RT patients. The differing conclusions among studies might be partially accounted for by the demographic differences and comorbidities between these 2 patient populations. Providers should continue to provide appropriate counseling concerning risks, benefits, and timing of SA for these patients.

Monoclonal Antibody Disrupts Biofilm Structure and Restores Antibiotic Susceptibility in an Orthopedic Implant Infection Model.

Bacterial biofilms on orthopedic implants are resistant to the host immune response and to traditional systemic antibiotics. Novel therapies are needed to improve patient outcomes. TRL1068 is a human monoclonal antibody (mAb) against a biofilm anchoring protein. For assessment of this agent in an orthopedic implant infection model, efficacy was measured by reduction in bacterial burden of Staphylococcus aureus, the most common pathogen for prosthetic joint infections (PJI). Systemic treatment with the biofilm disrupting mAb TRL1068 in conjunction with vancomycin eradicated S. aureus from steel pins implanted in the spine for 26 of 27 mice, significantly more than for vancomycin alone. The mechanism of action was elucidated by two microscopy studies. First, TRL1068 was localized to biofilm using a fluorescent antibody tag. Second, a qualitative effect on biofilm structure was observed using scanning electron microscopy (SEM) to examine steel pins that had been treated in vivo. SEM images of implants retrieved from control mice showed abundant three-dimensional biofilms, whereas those from mice treated with TRL1068 did not. Clinical Significance: TRL1068 binds at high affinity to S. aureus biofilms, thereby disrupting the three-dimensional structure and significantly reducing implant CFUs in a well-characterized orthopedic model for which prior tested agents have shown only partial efficacy. TRL1068 represents a promising systemic treatment for orthopedic implant infection.

MELD score predicts short-term outcomes after surgical management of proximal humerus fractures: a matched analysis.

Objective: We aimed to evaluate the difference in 30-day outcomes after surgical management of proximal humerus fractures (PHFs) between patients with and without chronic liver disease as defined by a MELD score greater than 10. Design: This was a retrospective database review. Setting: All centers participating in the American College of Surgeons National Surgical Quality Improvement Program database were included. Patients/Participants: Patients with proximal humerus fractures who (1) underwent ORIF, HA, or SA and (2) had calculable MELD scores were included. Intervention: Open reduction and internal fixation, hemiarthroplasty, or shoulder arthroplasty was used for treatment. Main outcome measurements: Thirty-day complications, mortality, readmission, and reoperation rates were measured. Results: Of the total 1732 PHF patients identified, 300 had a MELD score higher than 10. After propensity matching by significant covariates, MELD score higher than 10 was found to be significantly associated with higher rates of 30-day mortality, 30-day readmission, transfusion within 72 hours, and systemic complications. Among patients with a MELD score higher than 10, treatment with SA or HA instead of ORIF was associated with a higher rate of transfusion and longer operative time. There were no significant differences between treatment cohorts regarding mortality, reoperation, readmission, or complications. Conclusions: A MELD score higher than 10 is associated with higher risk of surgical complications, transfusion, and death in patients undergoing surgery for proximal humerus fractures. Among patients with a MELD score higher than 10, ORIF was associated with a lower transfusion rate and shorter operative time than arthroplasty or hemiarthroplasty. Level of Evidence: Prognostic Level III.

Cementless Compared to Cemented Total Knee Arthroplasty is Associated With More Revisions Within 1 Year of Index Surgery.

Background: Cementless total knee arthroplasties (TKAs) have gained renewed interest due to improved implant designs and lower rates of revision than its cemented counterparts. The purpose of this study was to compare revision rates between cemented vs cementless TKAs within 1 year of primary arthroplasty. Methods: This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had undergone cemented and cementless TKAs and subsequent surgical revisions. An unadjusted univariate analysis of patient demographics, Charlson Comorbidity Index score, and surgical revisions at 90 days and 1 year after TKA was performed using chi-squared testing. Multivariate logistic regression analyses were subsequently performed for 1-year surgical complications requiring revision. Results: Of 324,508 patients, 312,988 (96.45%) underwent cemented TKAs, and 11,520 (3.55%) underwent cementless TKAs. Patients undergoing cementless TKA tended to be younger than patients undergoing cemented TKA (63.67 ± 9.15 cementless vs 66.22 ± 8.85 cemented, P < .001). Univariate chi-squared testing showed that cementless patients were more likely to require 1-component femoral or tibial revision at 90 days and 1 year, irrigation and debridement at 90 days and 1 year, and arthroscopy with lysis of adhesions at 1 year only. Similar findings were observed for these 3 revision procedures at 1 year after correcting for age, gender, and Charlson Comorbidity Index score using multivariate logistic regression analysis as cementless TKA patients had higher odds ratios for each of the revisions. Conclusions: Small but significant differences were found in surgical revisions among cementless TKAs when compared to cemented TKAs within 1 year of the index procedure.

Renal Transplant Patients Have a Lower Risk of Complications and Mortalities After Total Knee Arthroplasty Compared to Those on Hemodialysis: A Large National Database Study.

BACKGROUND: Total knee arthroplasty (TKA) in end-stage renal disease is associated with complications. Controversy exists whether elective TKA should be performed while patients are on hemodialysis (HD) or following renal transplant (RT). This study compares TKA outcomes in HD versus RT patients. METHODS: A national database was retrospectively reviewed using International Classification of Diseases codes to identify HD and RT patients who underwent primary TKA from 2010 to 2018. Demographics, comorbidities, and hospital factors were compared using Wald and Chi-squared tests. The primary outcome was in-hospital mortalities while secondary outcomes included quality outcomes and medical/surgical complications. Multivariate regressions were used to determine independent associations. Significance was determined with a 2-tailed P value of .05. There were 13,611 patients who underwent TKA (61.1 HD and 38.9% RT). Patients who had RT were younger, had fewer comorbidities, and more likely to have private insurance. RESULTS: The RT patients had a lower rate of mortality (odds ratio (OR) 0.23, P < .01)), complications (OR 0.63, P < .01), cardiopulmonary complications (OR 0.44, P = .02), sepsis (OR 0.22, P < .001), and blood transfusion (OR 0.35, P < .001) during the index hospitalization. This cohort was also found to have decreased length of stay (-2.0 days, P < .001), non-home discharge (OR 0.57, P < .001), and hospital cost (-$5,300, P < .001). Patients who had RT had a lower rate of readmission (OR 0.54, P < .001), periprosthetic joint infection (OR 0.50, P < .01), and surgical site infection (OR 0.37, P < .001) within 90 days. CONCLUSION: These findings suggest that HD patients are a high-risk population in TKA compared to RT patients and warrant stringent perioperative monitoring.

Comparison of total elbow arthroplasty complications between various surgical indications at 90-day and 1-year follow-up in 1600 elbows.

BACKGROUND: Total elbow arthroplasty (TEA) was traditionally a mainstay of treatment for patients with severe inflammatory arthritis. Recently, the indications for TEA have expanded, and TEA has grown into a versatile procedure that can be used to treat several pathologies of the elbow. The objective of this study was to compare complication rates between TEAs performed for rheumatoid arthritis (RA), fracture (FX), or osteoarthritis (degenerative joint disease [DJD]). METHODS: A retrospective analysis of the MUExtr data set of the PearlDiver national database was performed. International Classification of Diseases, Tenth Revision codes were used to identify patients who underwent TEA from 2010-2020 and to separate them into RA, FX, and DJD cohorts. Demographic characteristics, comorbidities, and hospital data were identified and compared using analysis of variance. Systemic complications at 90 days and surgical complications at both 90 days and 1 year were compared using multivariable logistic regression. Surgical complications included wound dehiscence, hematoma, deep infection, periprosthetic FX, stiffness, instability, triceps injury, nerve injury, and need for revision. RESULTS: We identified 1600 patients (DJD, 38.9%; FX, 48.8%; and RA, 12.3%). The majority of patients in all 3 cohorts were female patients, with the RA group having a significantly higher percentage of female patients than the FX and DJD groups (87.3% vs. 81.4% and 76.9%, respectively; P = .003). No significant differences in systemic complications and surgical complications were noted between all 3 groups at 90 days postoperatively. After controlling for patient factors, FX patients were more likely to have elbow stiffness (odds ratio, 1.53; P = .006) and less likely to have a triceps injury (odds ratio, 0.26; P < .001) at 1 year than were RA or DJD patients. CONCLUSION: The indications for TEA have expanded over the past 10 years, with nearly half of all cases being performed for FX. At 1 year postoperatively, TEAs performed for FX have a significantly lower rate of triceps injury and higher rate of elbow stiffness than TEAs performed for other indications. This finding is important to consider when preoperatively planning, as well as when discussing expected outcomes with patients prior to surgery, especially with the expanded incidence of TEA for FX being performed over the past decade.

Geriatric Distal Femur Fractures: Equivalent Long-Term Reoperation Rates Between Fixation and Primary Arthroplasty.

OBJECTIVE: Our primary objectives were to (1) determine the rate of requiring conversion to arthroplasty after open reduction internal fixation (ORIF) of geriatric distal femur fractures and (2) compare 10-year reoperation rates after ORIF versus primary arthroplasty for geriatric distal femur fractures. DESIGN: Propensity-matched retrospective cohort study. SETTING: All centers participating in the California Office of Statewide Health Planning and Development (OSHPD) database. PATIENTS/PARTICIPANTS: All patients 65 years of age or older who underwent operative management of a distal femur fracture between 2000 and 2017. INTERVENTION: ORIF, total knee arthroplasty (TKA), or distal femur replacement (DFR). MAIN OUTCOME MEASUREMENTS: Reoperation. RESULTS: A total of 16,784 patients with geriatric distal femur fracture were identified, of which 16,343 (97.4%) underwent ORIF. The cumulative incidence of conversion to arthroplasty within 10 years of ORIF was found to be 3.5%, with young age and female sex identified as risk factors for conversion. There was no significant difference in 10-year reoperation-free survival rate between propensity-matched patients undergoing ORIF versus primary arthroplasty (94.5% vs. 96.2%, P = 0.659). There were no differences in short-term complication or readmission rates between matched treatment cohorts, but arthroplasty was associated with a higher rate of wound infection within 90 days (2.0% vs. 0.2%, P = 0.011). CONCLUSIONS: The 10-year cumulative incidence of conversion to arthroplasty after ORIF was found to be low. There was no significant difference in long-term reoperation-free survival rates between patients undergoing ORIF versus primary arthroplasty. Primary arthroplasty was associated with significantly higher rates of acute wound or joint infection. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Short-term outcomes of periprosthetic compared to native distal femur fractures, a national database study.

BACKGROUND: Distal femur fractures (DFFx) are highly morbid injuries with a complication rate comparable to hip fractures. Rising rates of total knee arthroplasty (TKA) have led to increasing rates of periprosthetic DFFx (pDFFx). We sought to determine how pDFFx complication rates differed from native DFFx (nDFFx). METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was used to identify patients who sustained pDFFx or nDFFx between 2012 and 2018. Patients were further stratified by operative treatment: open reduction internal fixation (ORIF) or distal femur replacement (DFR). Multivariate logistic regression was used to compare 30-day complication rates between pDFFx versus nDFFx and, among pDFFx patients, ORIF versus DFR or revision TKA (rTKA). RESULTS: 563 patients with pDFFx and 2259 patients with nDFFx were identified between 2012 and 2018. pDFFx patients had significantly lower rates of ORIF than nDFFx patients (36.4 vs 95.4%, p < 0.001). On multivariate analysis, pDFFx were associated with a higher rate of surgical site complications (OR 2.48, p = 0.009) compared to nDFFx. There were no differences in mortality, reoperations, major complications, rate of blood transfusion, venous thromboembolism and disposition. In patients with pDFFx, patients undergoing DFR/rTKA were more likely to be discharged home versus a rehab facility, compared to those undergoing ORIF (OR 2.62, p < 0.001). CONCLUSIONS: In this first large registry study comparing pDFFx and nDFFx, we find similar outcomes between these groups in the first 30 days after surgery. Patients with pDFFx did have higher rates of surgical site complications, including infection and dehiscence. In pDFFx patients, those undergoing DFR were more likely to return home post-operatively.

Comparison of total hip arthroplasty outcomes between haemodyalisis and renal transplant patients.

INTRODUCTION: Total hip arthroplasty (THA) in end-stage renal disease (ESRD) patients is associated with increased complications. Controversy exists whether elective THA should be performed while these patients are on haemodialysis (HD) or following renal transplant (RT). This study seeks to compare THA outcomes in HD versus RT patients. METHODS: A national database was retrospectively reviewed using ICD codes to identify all HD and RT patients who underwent primary THA from 2010 to 2018. Demographics, comorbidities, and hospital factors were compared between cohorts using Wald and chi-square tests. The primary outcome was in-hospital mortality, while secondary outcomes included length of stay (LOS), non-home discharge, cost, readmission, and medical/surgical complications. Multivariate regression was used to determine independent associations. Significance was determined with a 2-tailed p-value of 0.05. RESULTS: 11,133 patients underwent THA, 61.6% HD and 39.4% RT patients. RT patients were younger, had fewer comorbidities, and more likely to have private insurance. After adjusting for these differences, RT patients had a lower rate of mortality (OR 0.31, p = 0.01), complications (OR 0.54, p < 0.01), cardiopulmonary complications (OR 0.54, p = 0.04), sepsis (OR 0.43, p < 0.01), and blood transfusion (OR 0.39, p < 0.001) during the index hospitalisation. RT was associated with decreased LOS (-2.0 days, p < 0.001), non-home discharge (OR 0.35, p < 0.001), and hospital cost (-$6,000, p < 0.001). RT had a lower rate of readmission (OR 0.60, p < 0.001) and revision surgery (OR 0.24, p = 0.01) within 90 days. CONCLUSIONS: These findings suggest HD patients are a high-risk population in THA compared to RT patients and warrant stringent perioperative monitoring.

Comparison of complication profiles for femoral neck, intertrochanteric, and subtrochanteric geriatric hip fractures.

INTRODUCTION: Most geriatric hip fractures occur in the femoral neck (FN) and intertrochanteric (IT) regions of the femur, while a minority occur in the subtrochanteric (ST) region. Relative outcomes based on the anatomical subtype of fracture are not well studied. This study characterizes postoperative complications and outcomes of hip fractures distinguished by anatomic region. MATERIALS AND METHODS: The targeted hip fracture series of the American College of Surgeons National Surgical Quality Improvement Program database was queried to identify geriatric (≥ 65 years) patients who sustained operative FN, IT, and ST hip fractures. Primary patient demographic and perioperative data were collected and correlated with 30-day postoperative complications and outcomes. Multivariate regression was used to calculate relative risks of adverse events (AEs) between groups. RESULTS: In total, 8220 geriatric hip fracture patients were identified. Risk-adjusted 30-day mortality was not significantly different between patients with ST (5.8%, p = 0.735) and IT (7.3%, p = 0.169) femur fractures relative to those with FN fractures (6.6%). The overall risk-adjusted rate of minor and major medical AEs within 30 days and risk-adjusted rate of wound complications was not significantly different between FN, IT, and ST fractures. Patients with IT [34.4%, OR 2.35 (2.35-3.08), p < 0.001] and ST fractures [49.8%, OR 5.94 (4.58-7.70), p < 0.00] had higher risk-adjusted incidence of postoperative blood transfusion relative to FN fractures (18.5%). Furthermore, patients with IT fractures had a slightly lower risk-adjusted incidence of unplanned reoperation [2.1 vs. 2.7%, OR 0.69 (0.47-0.99), p = 0.046] and hospital readmission (7.8 vs. 9.2%, OR 0.76 [0.63-0.91], p = 0.003) than patients with FN fractures. CONCLUSIONS: With respect to anatomic region, geriatric hip fractures have similar short-term mortality and medical AE profiles with differences in transfusion, reoperation, and readmission rates. Knowledge of these short-term outcomes may guide surgeons in counseling hip fracture patients peri-operatively.

Biphasic bone graft substitute in revision total hip arthroplasty with significant acetabular bone defects : a retrospective analysis.

AIMS: Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. METHODS: We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures. RESULTS: Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening. CONCLUSION: Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation.Cite this article: Bone Jt Open 2022;3(12):991-997.

Reduced Costs, Complications, and Length of Stay After Arthroscopic Versus Open Irrigation and Débridement for Knee Septic Arthritis.

BACKGROUND: In the treatment of native knee bacterial septic arthritis, the optimal irrigation and débridement modality-arthroscopic versus open-is a matter of controversy. We aim to compare revision-free survival, complications, and resource utilization between these approaches. METHODS: The National Readmission Database was queried from 2016 to 2019 to identify patients using International Classification of Diseases, 10th revision, diagnostic and procedure codes. Days to revision irrigation and débridement (I&D), if any, were calculated for patients during index admission or subsequent readmissions. Multivariate regression was used for healthcare utilization analysis. Survival analysis was done using Kaplan-Meier analysis and Cox proportional hazard regression. RESULTS: A total of 14,365 patients with native knee septic arthritis undergoing I&D were identified, 8,063 arthroscopic (56.1%) and 6,302 open (43.9%). The mean follow-up was 148 days (interquartile range 53 to 259). A total of 2,156 patients (15.0%) underwent revision I&D. On multivariate analysis, arthroscopic I&D was associated with a reduction in hospital costs of $5,674 and length of stay of 1.46 days (P < 0.001 for both). Arthroscopic I&D was associated with lower overall complications (odds ratio [OR] 0.63, P < 0.001), need for blood transfusion (OR 0.58, P < 0.001), and wound complications (OR 0.32, P < 0.001). Revision-free survival after index I&D was 95.3% at 3 days, 91.0% at 10 days, 88.3% at 30 days, 86.0% at 90 days, and 84.5% at 180 days. No statistically significant difference was observed between surgical approaches on Cox modeling. DISCUSSION: Risk of revision I&D did not differ between arthroscopic and open I&D; however, arthroscopy was associated with decreased costs, length of stay, and complications. Additional study is necessary to confirm these findings and characterize which patients require an open I&D. LEVEL OF EVIDENCE: III.

Platelet-rich plasma use for hip and knee osteoarthritis in the United States.

BACKGROUND: Hip and knee osteoarthritis (OA) are rising in prevalence and increasingly affecting younger patients. There is a rising demand for therapeutics to address its growing disease burden. Platelet-rich plasma (PRP) therapy has been used to treat various musculoskeletal conditions, but its role in OA treatment is not well understood. Even still, there is significant interest in this biologic for treatment of OA. The purpose of this study was to determine the PRP utilization trends in the United States for hip and knee OA. METHODS: This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had received PRP injections for hip and knee OA from 2010 to 2018. Injection incidence was evaluated on an annual basis and by patient demographics, geographic distribution, and medical specialty under which the treatment was administered. RESULTS: A total of 3,884 PRP injections were administered over the study period, 15% for hip OA and 85% for knee OA. PRP injections per 100,000 patient cases increased by an average year-over-year percentage of 53% and 12% for hip and knee OA, respectively. The highest injection incidences were observed in patients younger than 44 years of age. 58% of both hip and knee PRP injections were administered in general orthopaedic practices. CONCLUSION: These findings show that PRP is increasingly being used as a treatment modality for hip and knee OA. There is a need for further research on its long term outcomes.

Subsidence of monoblock and modular titanium fluted tapered stems in revision hip arthroplasty: A retrospective multicentre comparison study.

Background: Tapered, fluted, titanium (TFT) stems have shown good clinical outcomes in revision total hip arthroplasty (rTHA), however concerns exist regarding early subsidence. This study compares subsidence between a modern monoblock 3-degree and a modular 2-degree TFT stem in rTHA. Methods: A retrospective, international multicentre comparative study was conducted including 64 rTHA in 63 patients. A monoblock TFT stem was used in 37 cases and a modular TFT stem was used in 27 cases. Patient demographics, Paprosky femoral bone loss classification, bicortical contact and stem subsidence were recorded at minimum four week follow up. Results: There was no statistically significant difference in overall subsidence (p = 0.318) or the rate of subsidence >10 mm between stems. Mean subsidence was 2.13 mm in the monoblock group and 3.15 mm in the modular group. Two stems subsided >10 mm: one in each group. There was no difference in bicortical contact between groups (p = 0.98). No re-revisions were performed. Conclusions: We found no difference in subsidence between the two stems. Surgeons may consider the use of monoblock stems in rTHA as they have comparably low rates of subsidence and eliminate the small but potentially catastrophic risk of implant fracture at modular junctions associated with modular stems.

Renal disease is a risk factor for complications and mortality after open reduction internal fixation of proximal humerus fractures.

Background: Renal osteodystrophy predisposes renal disease patients to fracture. Proximal humerus fractures (PHFs) frequently undergo open reduction internal fixation (ORIF); however, the effect of renal disease on outcomes is unknown. Methods: A retrospective review of the Nationwide Readmissions Database used International Classification of Diseases, 9th Revision, codes to identify patients who underwent ORIF for closed PHF from 2010 to 2014 with no renal disease, predialysis chronic renal disease (CRD), and end-stage renal disease (ESRD). Results: A total of 85,433 patients were identified, including 5498 (6.4%) CRD and 636 (0.7%) ESRD. CRD and ESRD patients had increased age, comorbidities, and rates of Medicare insurance. After adjusting for differences, CRD and ESRD patients were at increased risk of any complication (odds ratio [OR] 2.48, 1.66), blood transfusion (OR 1.85, 3.31), respiratory complications (OR 1.14, 1.59), acute renal failure (OR 4.80, 1.67), systemic infection (OR 2.00, 3.14), surgical site infection (OR 1.52, 3.87), longer length of stay (7.1 and 12.9 days vs. 5.9 days), and higher cost ($21,669 and $35,413 vs. $20,394) during index hospitalization, as well as surgical site infection (OR 1.43, 3.03) and readmission (OR 1.61, 3.69) within 90 days of discharge, respectively, compared with no renal disease patients. During index hospitalization, CRD patients also had increased risk for periprosthetic fracture (OR 4.97) and cardiac complications (OR 1.47), whereas ESRD patients had increased risk of mortality (OR 5.79), wound complication (2.67), and deep vein thrombosis (OR 16.70). Conclusion: These findings suggest renal patients are at increased risk for complications after PHF ORIF, highlighting the importance of close perioperative monitoring and appropriate patient selection in this population, including strong consideration of nonoperative management.