Novel Technique for the Identification of Hip Implants Using Artificial Intelligence.

BACKGROUND: The anticipated growth of total hip arthroplasty will result in an increased need for revision total hip arthroplasty. Preoperative planning, including identifying current implants, is critical for successful revision surgery. Artificial intelligence (AI) is promising for aiding clinical decision-making, including hip implant identification. However, previous studies have limitations such as small datasets, dissimilar stem designs, limited scalability, and the need for AI expertise. To address these limitations, we developed a novel technique to generate large datasets, tested radiographically similar stems, and demonstrated scalability utilizing a no-code machine learning solution. METHODS: We trained, validated, and tested an automated machine learning-implemented convolutional neural network to classify 9 radiographically similar femoral implants with a metaphyseal-fitting wedge taper design. Our novel technique uses computed tomography-derived projections of a 3-dimensional scanned implant model superimposed within a computed tomography pelvis volume. We employed computer-aided design modeling and MATLAB to process and manipulate the images. This generated 27,020 images for training (22,957) and validation (4,063) sets. We obtained 786 test images from various sources. The performance of the model was evaluated by calculating sensitivity, specificity, and accuracy. RESULTS: Our machine learning model discriminated the 9 implant models with a mean accuracy of 97.4%, sensitivity of 88.4%, and specificity of 98.5%. CONCLUSIONS: Our novel hip implant detection technique accurately identified 9 radiographically similar implants. The method generates large datasets, is scalable, and can include historic or obscure implants. The no-code machine learning model demonstrates the feasibility of obtaining meaningful results without AI expertise, encouraging further research in this area.

Recurrent Periprosthetic Joint Infections: Diagnosis, Management, and Outcomes.

Periprosthetic joint infection (PJI) remains one of the most common complications after total joint arthroplasty. It is challenging to manage, associated with significant morbidity and mortality, and is a financial burden on the health care system. Failure of 2-stage management for chronic PJI is not uncommon. Repeat infections are oftentimes polymicrobial, multiple drug-resistant microorganisms, or new organisms. Optimizing the success of index 2-stage revision is the greatest prevention against failure of any subsequent management options and requires a robust team-based approach.

Assessing the Diagnostic Accuracy of Next-Generation Sequencing in Patients With Antibiotic Spacers Before Reimplantation.

Use of molecular sequencing modalities in periprosthetic joint infection diagnosis and organism identification has gained popularity recently. To date, there is no diagnostic test that reliably predicts infection eradication in patients with antibiotic spacers. The purpose of this study was to compare the diagnostic accuracy of next-generation sequencing (NGS), culture, the Musculoskeletal Infection Society (MSIS) criteria, and the criteria by Parvizi et al in patients with antibiotic spacers. In this retrospective study, aspirate or tissue samples were collected from 38 knee and 19 hip antibiotic spacers for routine diagnostic workup for the presence of persistent infection and sent to the laboratory for NGS. The kappa statistic along with statistical differences between diagnostic studies were calculated using the chi-square test for categorical data. The kappa coefficient for agreement between NGS and culture was 0.27 (fair agreement). The percentages of positive and negative agreement were 22.8% and 42.1%, respectively, with a total concordance of 64.9%. There were 12 samples that were culture positive and NGS negative. Eight samples were NGS positive but culture negative. The kappa coefficient was 0.42 (moderate agreement) when comparing NGS with MSIS criteria. In our series, NGS did not provide sufficient agreement compared with culture or MSIS criteria in the setting of an antibiotic spacer. A reliable diagnostic indicator for reimplantation has yet to be identified. [Orthopedics. 2024;47(1);46-51.].

The Challenge of Emerging Resistant Gram-Positive Pathogens in Hip and Knee Periprosthetic Joint Infections.

➤: An increase in resistant bacterial pathogens has occurred over the last 4 decades. ➤: Careful patient selection and improving or correcting risk factors for periprosthetic joint infection (PJI) before elective surgical treatment are strongly recommended. ➤: Appropriate microbiological methods, including those used to detect and grow Cutibacterium acnes, are recommended. ➤: Antimicrobial agents used in the prevention or management of infection should be selected appropriately and the duration of therapy should be carefully considered in order to mitigate the risk of developing bacterial resistance. ➤: Molecular methods including rapid polymerase chain reaction (PCR) diagnostics, 16S sequencing, and/or shotgun and/or targeted whole-genome sequencing are recommended in culture-negative cases of PJI. ➤: Expert consultation with an infectious diseases specialist (if available) is recommended to assist with the appropriate antimicrobial management and monitoring of patients with PJI.

Obturator Anterior Dislocation After Direct Anterior Total Hip Arthroplasty in a Patient with Ehlers-Danlos Syndrome: A Case Report.

CASE: A 71-year-old woman with Ehlers-Danlos syndrome suffered an atraumatic obturator dislocation status post direct anterior total hip arthroplasty. A closed reduction under conscious sedation was attempted, but was unsuccessful. Repeat closed reduction under full general anesthesia with paralysis and fluoroscopic guidance was successful at reducing the femoral prosthesis out of the pelvis and back into an appropriate position. CONCLUSION: Atraumatic obturator dislocations after total hip arthroplasty are exceedingly rare. General anesthesia with full paralysis is helpful for a successful closed reduction, and open reduction may be necessary to remove the femoral prosthesis from the pelvis.

Predictors of Reinfection in Prosthetic Joint Infections Following Two-Stage Reimplantation.

BACKGROUND: Two-stage reimplantation is an effective treatment for periprosthetic joint infection (PJI). Many factors are involved in the variable success of this procedure. The purpose of this study is to examine the relationship between patient risk factors, comorbidities, and the pathogen on reinfection rates following two-stage reimplantation. METHODS: We evaluated 158 patients treated for PJI from 2008-2019. Only patients who had completed a two-stage exchange were included. Patient demographics, comorbidities, laboratory values, time-to-reimplantation, pathogen, antibiotic sensitivities, host status, and reinfection rates were assessed. Multivariate analysis was performed to identify correlation between risk factors and reinfection. A P-value < .05 was considered statistically significant. RESULTS: 31 patients experienced a reinfection (19.6%). There was a statistically significant association between infection with Methicillin Sensitive Staphylococcus Aureus (MSSA) and reinfection (P = .046). Patients with a reinfection also had a significantly greater median serum C-reactive protein (CRP) level (12.65 g/dL) at the time of diagnosis compared to patients without a reinfection (5.0 g/dL) (P = .010). Median Erythrocyte Sedimentation Rate (ESR) (56 in no re-infection and 69 in re-infection) and time-to-reimplantation (101 days in no reinfection and 141 days in reinfection) demonstrated a trend toward an association with re-infection but were not statistically significant (P = .055 and P = .054 respectively). CONCLUSION: As the number of arthroplasties continue to rise, PJIs are increasing proportionately and represent a significant revision burden. Elevated C-reactive protein (CRP) levels and Methicillin Sensitive Staphylococcus aureus (MSSA) infection were strongly associated with failure of a two-stage reimplantation. While not statistically significant with our numbers, there were strong trends toward an association between elevated Erythrocyte Sedimentation Rate (ESR), longer time-to-reimplantation, and reinfection.

Long Term Results of Two-Stage Revision for Chronic Periprosthetic Knee Infection: A Multicenter Study.

BACKGROUND: Long-term reinfection and mortality rates and clinical outcomes with sufficient subject numbers remain limited for patients undergoing two-stage exchange arthroplasty for chronic periprosthetic knee infections. The purpose of this study was to determine the long-term reinfection, complication, and mortality following reimplantation for two-stage exchange following knee arthroplasty. METHODS: Retrospective review of 178 patients who underwent two-stage exchange knee arthroplasty for chronic PJI at three large tertiary referral institutions with an average of 6.63-year follow-up from reimplantation from 1990 to 2015. Rates of reinfection, mortality, and all-cause revision were calculated along with the cumulative incidence of reinfection with death as a competing factor. Risk factors for reinfection were determined using Cox multivariate regression analysis. RESULTS: Overall rate of infection eradication was 85.41%, with a mortality rate of 30.33%. Patients with minimum 5-year follow-up (n = 118, average 8.32 years) had an infection eradication rate of 88.98%, with a mortality rate of 33.05%. CONCLUSION: This is a large series with long-term follow-up evaluating outcomes of two-stage exchange knee arthroplasty resulting in adequate infection eradication and high mortality. Results were maintained at longer follow-up. This technique should be considered in patients with chronic PJI; however, realistic expectations regarding long-term outcomes must be discussed with patients.

Two-Stage Reimplantation of a Prosthetic Hip Infection: Systematic Review of Long-Term Reinfection and Pathogen Outcomes.

BACKGROUND: Although two-stage exchange for chronic periprosthetic hip infections remains an effective option for infection eradication, long-term outcome reporting remains scarce. Compiling outcomes data for this standard of care is necessary to characterize long-term reinfection risk and identify bacteria associated with reinfection. The purpose of our study was to perform a systematic review to determine the long-term risk of reinfection after two-stage reimplantation. The second purpose was to identify the proportion of reinfections caused by the same or different organism(s) relative to the index infection. METHODS: We performed a systematic review of two-stage reimplantation randomized control trials, cohort studies, and case series for the treatment of periprosthetic joint infections, yielding 320 unique citations for abstract review, of which 138 were reviewed in full. We collected reinfection data including the timing of reinfection after successful reimplantation and the bacteria identified at reinfection. Meeting inclusion criteria were 28 studies with 2047 patients and 2055 hips that completed both reimplantation stages with just seven studies having greater than 24 month follow-up. RESULTS: Studies with longer average follow-up reported significantly higher all-time reinfection rates (P = .042). Among studies with at least 5 years of follow-up, the risk of reinfection was 10.25% (8.21-12.47). Among studies with minimum follow-up of at least 24 months, the 24-month rate of reinfection was 4.58% (2.17-7.66), which increased to 7.34% (4.44-10.82) by final follow-up. Only 12 studies reported index and recurrent pathogen data. In those studies, 3.00% (1.19-5.38) of all hips which completed both reimplantation stages were reinfected by a new pathogen, and 1.70% (0.52-3.35) of patients became reinfected by recurrent pathogens. CONCLUSION: While the majority of two stage reimplantation literature follows patients for two years, there is significant risk of reinfection into the long term. Further studies with detailed outcomes and long-term follow-up are needed to identify factors associated with late infections.

Comparison of 3D Printed Spherical Implants versus Femoral Head Allografts for Tibiotalocalcaneal Arthrodesis.

Successful tibiotalocalcaneal (TTC) arthrodesis can be difficult to achieve in patients with bulk bone defects even with the use of femoral head allograft. Retrograde intramedullary nail placement through custom 3-dimensional (3D) spherical implants is an innovative option for these patients. The purpose of this study was to compare fusion rates, graft resorption, and complication rates between patients undergoing TTC fusion with 3D sphere implants versus femoral head allografts. Patients who underwent TTC arthrodesis with an intramedullary nail along with a 3D spherical implant (n = 8) or femoral head allograft (n = 7) were included in this study. The rate of successful fusion of the tibia, calcaneus, and talar neck to the 3D sphere or femoral head allograft was compared between the groups. The rate of total fused articulations was significantly higher in the 3D sphere group (92%) than the femoral head allograft group (62%; p = .018). The number of patients achieving successful fusion of all 3 articulations was higher in the 3D sphere group (75%) than the femoral head allograft group (42.9%, p = .22). The rate of graft resorption was significantly higher in the femoral head allograft group (57.1%) than the 3D sphere group (0%, p = .016). There were no significant differences between the groups in terms of complications. These data demonstrate that the use of a custom 3D printed sphere implant is safe in patients with severe bone loss undergoing TTC arthrodesis with a retrograde intramedullary nail and may result in improved rates of successful arthrodesis.

Single vs 2-Stage Revision for the Treatment of Periprosthetic Joint Infection.

Periprosthetic joint infection (PJI) is one of the most devastating complications following total joint arthroplasty, accounting for a projected 10,000 revision surgeries per year by 2030. Chronic PJI is complicated by the presence of bacterial biofilm, requiring removal of components, thorough debridement, and administration of antibiotics for effective eradication. Chronic PJI is currently managed with single-stage or 2-stage revision surgery. To date, there are no randomized, prospective studies available evaluating eradication rates and functional outcomes between the 2 techniques. In this review, both treatment options are described with the most current literature to guide effective surgical decision-making that is cost-effective while decreasing patient morbidity.

Comparison of Tibiotalocalcaneal Arthrodeses Using a Sustained Dynamic Compression Nail Versus Nondynamized Nails.

Background. Tibiotalocalcaneal (TTC) arthrodesis is a common treatment option for hindfoot arthritis and deformity. Loss of compression over time with statically locked nails may contribute to nonunion. A novel retrograde intramedullary nail with an internal pseudoelastic component has recently been used to provide sustained dynamic compression (SDC). The purpose of this study was to compare fusion rates and time to union between the SDC and nondynamized (ND) nails. Methods. All patients who underwent TTC arthrodesis with an intramedullary nail at a single institution from 2013 to 2017 and who had at least 1 year of follow-up were included in this study. Baseline patient and operative characteristics were collected and compared between the sustained SDC and ND nail groups. The rate of successful fusion, time to union, and complications were compared between the groups. Results. The SDC cohort had a significantly faster time to union by 3.9 months (P = .049). The SDC cohort had a higher fusion rate (78.0%) compared with the ND nail cohort (75.0%), although this was not statistically significant (P = .75). The SDC nail was used significantly (P < .05) more often in patients with known risk factors for nonunion, including female sex, smoking, revision surgery, prior trauma, and patients requiring 3D cage implants for significant bone loss. There were no differences between the groups in terms of complications. Conclusion. The SDC nail has been shown to achieve successful arthrodesis in a population at high risk for nonunion, using less hardware, and at a faster rate than ND nails. Level of Evidence: Level III: Retrospective, comparative study.

Prior Hip Arthroscopy Increases Risk for Perioperative Total Hip Arthroplasty Complications: A Matched-Controlled Study.

BACKGROUND: Arthroscopic hip surgery is becoming increasingly popular for the treatment of femoroacetabular impingement and labral tears. Reports of outcomes of hip arthroscopy converted to total hip arthroplasty (THA) have been limited by small sample sizes. The purpose of this study was to investigate the impact of prior hip arthroscopy on THA complications. METHODS: We queried our institutional database from January 2005 and December 2017 and identified 95 hip arthroscopy conversion THAs. A control cohort of 95 primary THA patients was matched by age, gender, and American Society of Anesthesiologists score. Patients were excluded if they had undergone open surgery on the ipsilateral hip. Intraoperative complications, estimated blood loss, operative time, postoperative complications, and need for revision were analyzed. Two separate analyses were performed. The first being intraoperative and immediate postoperative complications through 90-day follow-up and a second separate subanalysis of long-term outcomes on patients with minimum 2-year follow-up. RESULTS: Average time from hip arthroscopy to THA was 29 months (range 2-153). Compared with primary THA controls, conversion patients had longer OR times (122 vs 103 minutes, P = .003). Conversion patients had a higher risk of any intraoperative complication (P = .043) and any postoperative complication (P = .007), with a higher rate of wound complications seen in conversion patients. There was not an increased risk of transfusion (P = .360), infection (P = 1.000), or periprosthetic fracture between groups (P = .150). When comparing THA approaches independent of primary or conversion surgery, there was no difference in intraoperative or postoperative complications (P = .500 and P = .790, respectively). CONCLUSION: Conversion of prior hip arthroscopy to THA, compared with primary THA, resulted in increased surgical times and increased intraoperative and postoperative complications. Patients should be counseled about the potential increased risks associated with conversion THA after prior hip arthroscopy.

Traditional Laboratory Markers Hold Low Diagnostic Utility for Immunosuppressed Patients With Periprosthetic Joint Infections.

BACKGROUND: Although predictive laboratory markers and cutoffs for immunocompetent patients are well-studied, similar reference ranges and decision thresholds for immunosuppressed patients are less understood. We investigated the utility of typical laboratory markers in immunosuppressed patients undergoing aspiration of a prosthetic hip or knee joint. METHODS: A retrospective review of adult patients with an immunosuppressed state that underwent primary and revision total joint arthroplasty with a subsequent infection at our tertiary, academic institution was conducted. Infection was defined by Musculoskeletal Infection Society criteria. A multivariable analysis was used to identify independent factors associated with acute (<90 days) and chronic (>90 days) infection. Area under the receiver-operator curve (AUC) was used to determine the best supported laboratory cut points for identifying infection. RESULTS: We identified 90 patients with immunosuppression states totaling 172 aspirations. Mean follow-up from aspiration was 33 months. In a multivariate analysis, only synovial fluid cell count and synovial percent neutrophils were found to be independently correlated with both acute and chronic infection. A synovial fluid cell count cutoff value of 5679 nucleated cells/mm3 maximized the AUC (0.839) for predicting acute infection, while a synovial fluid cell count cutoff value of 1293 nucleated cells/mm3 maximized the AUC (0.931) for predicting chronic infection. CONCLUSION: Physicians should be aware of lower levels of synovial nucleated cell count and percentage of neutrophils in prosthetic joint infections of the hip or knee in patients with immunosuppression. Further investigation is necessary to identify the best means of diagnosing periprosthetic joint infection in this patient population.

Is There a Difference in Infection Risk Between Single and Multiple Doses of Prophylactic Antibiotics? A Meta-analysis.

BACKGROUND: The prevention of surgical site infection guidelines issued by the Centers for Disease Control and Prevention (CDC) recently recommended that only a single dose of preoperative antibiotics be administered to patients undergoing clean-contaminated procedures based on data from a variety of surgical disciplines. For orthopaedic procedures, where postoperative infections can have significant consequences, the existing evidence for this recommendation is widely debated. QUESTIONS/PURPOSES: Is there a difference in postoperative infection risk when utilizing a single dose of preoperative antibiotics compared with multiple doses of perioperative antibiotics for orthopaedic procedures where implants are placed? METHODS: MEDLINE, EMBASE, Google Scholar, and Cochrane were systematically reviewed for randomized controlled trials (RCTs) of a single dose of preoperative antibiotics compared with pre- and postoperative prophylaxis from 1980 to 2017 for all orthopaedic procedures where implants were being placed. Infection (both superficial and deep) as a primary outcome through all available followup was required for inclusion. Fourteen RCTs detailing 9691 orthopaedic procedures were included for analysis, including seven arthroplasty, one spine, and six general orthopaedic trials (two specific to hip fracture fixation). Pooled infection outcomes were analyzed with random-effects modeling in light of study heterogeneity. Bias was evaluated using the Cochrane risk of bias tool as well as a funnel plot for publication bias, and quality of evidence was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Bias was largely uncertain; however, a high risk of bias was noted in four studies. No significant overall publication bias was noted. The quality of evidence was determined to be very low based on the GRADE tool, downgraded based on risk of bias, inconsistency, and imprecision. Despite the quality of evidence, the data were pooled in light of the current recommendations from the CDC to critically evaluate the recommendation that a single dose of antibiotics be utilized. RESULTS: There were no differences in infection risk between single- versus multiple-dose groups (single: 83 of 4263 [2%], multiple: 101 of 5428 [2%]; odds ratio, 0.92 [95% confidence interval, 0.56-1.51]; p = 0.740, I = 36% for statistical heterogeneity). CONCLUSIONS: There is no difference in infection risk between a single dose and multiple doses of perioperative antibiotics for orthopaedic procedures where implants are utilized, consistent with recent recommendations. However, the quality of evidence for orthopaedic procedures is low, and a randomized study with a sufficient sample size is needed to examine the issue before universal adoption of a single antibiotic dose. LEVEL OF EVIDENCE: Level I, therapeutic study.

Preoperative Patient Profile in Total Hip and Knee Arthroplasty: Predictive of Increased Medicare Payments in a Bundled Payment Model.

BACKGROUND: The shift toward value-based bundled payment models in total joint arthroplasty highlights the need for identification of modifiable risk factors for increased spending as well as opportunities to mitigate perioperative treatment of chronic disease. The purpose of this study was to identify preoperative comorbidities that result in an increased financial burden using institutional data at a single institution. METHODS: We conducted a retrospective review of total joint arthroplasty patients and collected payment data from the Center for Medicare and Medicaid Services for each patient up to 90 days after surgery in accordance with the regulations of the Comprehensive Care for Joint Replacement initiative. Statistical analysis and comparison of preoperative profile and Medicare payments as a surrogate for cost were completed. RESULTS: Six hundred ninety-four patients were identified over a 4-year time period who underwent surgery before adoption of the Comprehensive Care for Joint Replacement but that met criteria for inclusion. The median total payment per patient episode of care was $20,048. Preoperative diagnosis of alcoholism, anemia, diabetes, and obesity was found to have a statistically significant effect on total payments. The model predicted a geometric mean increase from $1425 to $9308 for patients bearing these comorbidities. CONCLUSION: With Medicare payments as a surrogate for cost, we demonstrate that specific patient comorbidities and a cumulative increase in comorbidities predict increased costs. This study was based on institutional data rather than administrative data to gain actionable information on an institutional level and highlight potential flaws in research based on administrative data.

Short and Long-Term Postoperative Complications Following Total Joint Arthroplasty in Patients With Human Immunodeficiency Virus, Hepatitis B, or Hepatitis C.

INTRODUCTION: Due to advancement in treatment against human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV), the prevalence of this patient population electing to undergo total joint arthroplasty (TJA) is increasing. Current literature is scarce and conflicting especially when evaluating long-term surgical complications. The purpose of this study is to assess the postoperative medical and surgical complications following TJA in these patient populations. METHODS: Using a nationwide database between 2005 and 2012, 4 cohorts were created: patients with HIV, HCV, HBV, and HIV and HBV or HCV who underwent TJA. Cohorts were matched to a control group by age, gender, and Charlson Comorbidity Index. Thirty-day and 90-day medical complications and 90-day and 2-year surgical complications were evaluated using odds ratios with 95% confidence intervals. RESULTS: Following TJA, patients with HCV or HBV had increased risk of pneumonia, sepsis, joint infection, and revision surgery at 90 days and 2 years. Patients with HIV did not have increased risk of infection at 90 days and 2 years but did have increased risk of revision at 90 days (odds ratio 3.21, 95% confidence interval 1.31-7.84) following total hip arthroplasty. CONCLUSIONS: Patients with HIV, HBV, or HCV have an overall increased risk of postoperative medical and surgical complications following TJA. Patients with HBV or HCV are at risk of more complications than patients with HIV especially for infection within 90 days after TJA. Patients with HIV are at risk of mechanical complications but do not appear to be at significant risk for infection following total hip arthroplasty.