Use and Application of Large Language Models for Patient Questions Following Total Knee Arthroplasty.

BACKGROUND: A consumer-focused health care model not only allows unprecedented access to information, but equally warrants consideration of the appropriateness of providing accurate patient health information. Nurses play a large role in influencing patient satisfaction following total knee arthroplasty (TKA), but they come at a cost. A specific natural language artificial intelligence (AI) model, ChatGPT (Chat Generative Pre-trained Transformer), has accumulated over 100 million users within months of launching. As such, we aimed to compare: (1) orthopaedic surgeons' evaluation of the appropriateness of the answers to the most frequently asked patient questions after TKA; and (2) patients' comfort level in answering their postoperative questions by using answers provided by arthroplasty-trained nurses and ChatGPT. METHODS: We prospectively created 60 questions based on the most commonly asked patient questions following TKA. There were 3 fellowship-trained surgeons who assessed the answers provided by arthroplasty-trained nurses and ChatGPT-4 to each of the questions. The surgeons graded each set of responses based on clinical judgment as: (1) "appropriate," (2) "inappropriate" if the response contained inappropriate information, or (3) "unreliable," if the responses provided inconsistent content. Patients' comfort level and trust in AI were assessed using Research Electronic Data Capture (REDCap) hosted at our local hospital. RESULTS: The surgeons graded 44 out of 60 (73.3%) responses for the arthroplasty-trained nurses and 44 out of 60 (73.3%) for ChatGPT to be "appropriate." There were 4 responses graded "inappropriate" and one response graded "unreliable" provided by the nurses. For the ChatGPT response, there were 5 responses graded "inappropriate" and no responses graded "unreliable." There were 136 patients (53.8%) who were more comfortable with the answers provided by ChatGPT compared to 86 patients (34.0%) who preferred the answers from arthroplasty-trained nurses. Of the 253 patients, 233 (92.1%) were uncertain if they would trust AI to answer their postoperative questions. There were 127 patients (50.2%) who answered that if they knew the previous answer was provided by ChatGPT, their comfort level in trusting the answer would change. CONCLUSIONS: One potential use of ChatGPT can be found in providing appropriate answers to patient questions after TKA. At our institution, cost expenditures can potentially be minimized while maintaining patient satisfaction. Inevitably, successful implementation is dependent on the ability to provide information that is credible and in accordance with the objectives of both physicians and patients. LEVEL OF EVIDENCE: III.

Does needle penetration of the shoulder joint prior to arthroscopy increase infection risk? The effect of preoperative magnetic resonance arthrogram or corticosteroid injection.

BACKGROUND: Prior literature has associated preoperative corticosteroid shoulder injection (CSI) with infection following shoulder surgery. A recent study found an equally elevated risk of total knee arthroplasty infection with preoperative injection of either CSI or hyaluronic acid. The implication is that violation of a joint prior to surgery, even in the absence of corticosteroid, may pose an elevated risk of infection following orthopedic surgery. The aim of the present study was to determine whether violation of the shoulder joint for magnetic resonance arthrogram (MRA) poses an elevated risk of infection following shoulder arthroscopy, and to compare this risk to that introduced by preoperative CSI. METHODS: A national, all-payer database was queried to identify patients undergoing shoulder arthroscopy between January 2015 and October 2020. Patients were stratified into the following groups: (1) no CSI or MRA within 6 months of surgery (n = 5000), (2) CSI within 2 weeks of surgery (n = 1055), (3) CSI between 2 and 4 weeks prior to surgery (n = 2575), (4) MRA within 2 weeks of surgery (n = 414), and (5) MRA between 2 and 4 weeks prior to surgery (n = 1138). Postoperative infection (septic shoulder or surgical site infection) was analyzed at 90 days, 1 year, and 2 years, postoperatively. Multivariable logistic regression analysis controlled for differences among groups. RESULTS: MRA within 2 weeks prior to shoulder surgery was associated with an increased risk of infection at 1 year (odds ratio [OR], 2.17; P = .007), while MRA 2-4 weeks preceding surgery was not associated with an increased risk of postoperative infection at any time point. By comparison, CSI within 2 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.72; P = .022), 1 year (OR, 1.65; P = .005), and 2 years (OR, 1.63; P = .002) following surgery. Similarly, CSI 2-4 weeks prior to surgery was associated with an increased risk of postoperative infection at 90 days (OR, 1.83; P < .001), 1 year (OR, 1.62; P < .001), and 2 years (OR, 1.79; P < .001). CONCLUSION: Preoperative CSI within 4 weeks of shoulder arthroscopy elevates the risk of postoperative infection. Needle arthrotomy for shoulder MRA elevates the risk of infection in a more limited fashion. Avoidance of MRA within 2 weeks of shoulder arthroscopy may mitigate postoperative infection risk. Additionally, the association between preoperative CSI and postoperative infection may be more attributed to medication profile than to needle arthrotomy.

Core decompression is superior to nonoperative management for humeral head osteonecrosis: a systematic review.

BACKGROUND: Much of the literature on osteonecrosis has traditionally focused on the hip, which remains the most common site for this disease. The shoulder and the knee are the second most frequently affected sites (both approximately 10% of the incidence). There are a variety of techniques for managing this disease, and it is important to optimize this for our patients. This review aimed to compare the results of core decompression (CD) vs. nonoperative modalities for the treatment of osteonecrosis of the humeral head, including (1) success rate defined as lack of progression to further procedures (shoulder arthroplasty) and no need for further intervention; (2) clinical results (patient-reported pain and functional scores); and (3) radiological outcomes. METHODS: We queried PubMed and found 15 reports that fit the inclusion criteria for studies concerning the use of CD as well as studies discussing nonoperative treatment for stage I-III osteonecrotic lesions of the shoulder. A total of 9 studies encompassed 291 shoulders that underwent CD analyzed at a mean follow-up of 8.1 years (range, 67 months-12 years), and 6 studies examined 359 shoulders that underwent nonoperative management at a mean follow-up of 8.1 years (range, 35 months-10 years). Outcomes of CD and nonoperative management included success rate, number of shoulders requiring shoulder arthroplasty, and evaluation of several normalized patient-reported outcomes. We also assessed radiographic progression (pre- to postcollapse or further collapse progression). RESULTS: The mean success rate of CD for avoiding further procedures was 76.6% (226 of 291 shoulders) in stage I through stage III. Stage III shoulders avoided shoulder arthroplasty in 63% (27 of 43 shoulders). Nonoperative management resulted in a success rate of 13%, P < .001. In the CD studies, 7 of 9 showed improvements in clinical outcome measurements compared with 1 of 6 of the nonoperative studies. Radiographically, there was less progression in the CD group (39 of 191 shoulders [24.2%]) vs. the nonoperative group (39 of 74 shoulders [52.3%]) (P < .001). CONCLUSIONS: Given the high success rate and positive clinical outcomes reported, CD is an effective method for management, especially when compared with nonoperative treatment methods for stage I-III osteonecrosis of the humeral head. The authors believe that it should be used as treatment to avoid arthroplasty in patients who have osteonecrosis of the humeral head.

Antibiotic Prophylaxis is Often Unnecessary for Screening Colonoscopies Following Total Knee Arthroplasty.

BACKGROUND: Incidence of bacteremia following screening colonoscopy is low, but risk of hematogenous spread causing prosthetic joint infection (PJI) may exist in total knee arthroplasty (TKA) patients. In multivariate analyses, we examined PJI risk among 3 TKA cohorts: (1) colonoscopy recipients given antibiotic prophylaxis; (2) colonoscopy recipients not given antibiotic prophylaxis; and (3) no colonoscopy. We assessed 90-day to 1-year (A) PJI risk and (B) risk factors for postcolonoscopy PJI. METHODS: We queried a national, all-payer database for primary TKA recipients from 2010 to 2020. Patients who had colonoscopies and who did (n = 2,558) or did not have antibiotic prophylaxis (n = 20,000) were identified. These were compared those who did not undergo colonoscopy (n = 20,000). The 20,000 patients were randomly selected to mitigate type-1 errors. Multivariate regressions compared PJI risk factors, such as alcohol abuse (AA), rheumatoid arthritis (RA), and diabetes. RESULTS: Both colonoscopy cohorts had no increased PJI risk compared to noncolonoscopy (odds ratio (OR) ≤ 2.20, P ≥ .064). Alcohol abuse, diabetes, and RA were found to be risk factors further enhancing likelihood of PJI for TKA patients not receiving antibiotics undergoing colonoscopies (OR ≥ 1.35, P ≤ .044). CONCLUSION: Overall, antibiotic prophylaxis does not decrease PJI risk following colonoscopy TKA recipients. After adjusting for known risk factors, both colonoscopy cohorts demonstrated similar PJI risks compared to the noncolonoscopy cohort. However, AA, diabetes, and RA were associated with further increased PJI risk for TKA patients undergoing colonoscopies compared to those who did not. Therefore, if undergoing colonoscopy after TKA, our findings suggest that most patients do not need to have antibiotics except for these high-risk patients.

Does Preoperative Statin Exposure Reduce Prosthetic Joint Infections and Revisions Following Total Joint Arthroplasty?

INTRODUCTION: The pleiotropic effects of statins extend beyond managing cardiovascular health and are suggested to modulate Staphylococcus aureus biofilm formation with prosthetic joint infection (PJI) reduction. However, a large analysis of statin use prior to total joint arthroplasty (TJA) to determine infection and revision risk is lacking. We specifically evaluated: 90-day to two-year (1) prosthetic joint infection (PJIs); (2) revisions; and (3) respective risk factors. MATERIALS AND METHODS: We queried a national, all-payer database for patients undergoing either TKA or THA between 2010-2020. Chronic statin exposure was defined as >3 prescriptions filled within one-year prior to TJA (statin users). A control cohort of patients undergoing TJA without history of statin use prior was identified (statin naïve). Cohorts were matched 1:1 based on demographics and comorbidities (TKA: n=579,136; THA: n=202,092). Multivariate logistic regression was performed to evaluate risk factors for PJIs and revisions. RESULTS: Among TKA recipients, statin users had lower incidence of PJIs at one year (0.36 vs. 0.39%) to two years (0.45 vs. 0.49%) compared to the statin naïve (all, p≤0.007). Similarly, statin users had lower incidence of one- to two-year revisions (all, p≤0.048). Among THA recipients, statin users had lower incidence of PJIs at 90 days (0.37 vs. 0.45%) to two years (2% vs. 2.14%) (all, p<0.001). Similar trends were observed for 90-day to two-year revisions (all, p≤0.022). Statin use was independently associated with decreased odds of PJIs and revisions by one year. CONCLUSIONS: Statin use is associated with a reduced risk of PJIs and revisions from one to two years following TJA. It may be worthwhile to ensure patients take statin therapy if indicated for previously established cardiovascular guidelines.

The Efficacy of Platelet-Rich Plasma for the Treatment of Knee Osteoarthritis Symptoms and Structural Changes: A Systematic Review and Meta-Analysis.

BACKGROUND: Platelet-rich plasma (PRP) usage in orthopedics continues to rise, despite guidelines suggesting non-superiority to comparative cohorts. Therefore, we performed a systematic review and meta-analysis on PRP efficacy using two clinical assessments: (1) Visual Analog Scale and (2) Western Ontario and McMaster Universities Osteoarthritis Index. We assessed consistency and clinical relevancy by determining study heterogeneity (eg, sample sizes, ages, body mass index, arthritic severities, etc.). Comparative cohorts were: (A) hyaluronic acid (HA); (B) corticosteroid (CS); (C) normal saline (NS); and (D) exercise therapy. We performed sub-analyses of structural changes assessed on ultrasound, radiograph, or magnetic resonance imaging . METHODS: We utilized PubMed, Cochrane Library, and Embase databases up to December 1, 2021, according to Preferred Reporting Items for Systematic-Reviews and Meta-Analyses guidelines. Twenty-four studies met criteria, with comparisons to: HA (n = 11); CS (n = 6); NS (n = 5); and exercise therapy (n = 3). Seven studies assessed structural changes. Evaluations utilized a methodological scoring system. I2 statistics and forest plots pooled analyses and delineated study results. RESULTS: PRP led to Visual Analog Scale and Western Ontario and McMaster Universities Osteoarthritis Index improvements in most studies when compared to HA, CS, and NS (P ≤ .05). Comparison to exercise therapy resulted in inconclusive findings (P ≥ .05). However, substantial heterogeneity (I2 ≥ 76%) was reported due to study variability. No differences were found when assessing structural changes or cartilage thickness by magnetic resonance imaging (standardized mean difference -0.01 [-0.19, 0.18], P = .91). CONCLUSIONS: PRP may be associated with pain and functional improvements but was not clinically relevant (inconsistent study- and patient-metrics). In addition, PRP did not confer superiority when assessing knee-related structural changes.

Biologic Therapies for the Treatment of Knee Osteoarthritis: An Updated Systematic Review.

BACKGROUND: Use of "orthobiologics" continues to expand for patients who have knee osteoarthritis (OA). We sought to perform a systemic review of biologic therapies relative to comparative groups, including the following: (1) platelet-rich plasma (PRP); (2) bone marrow-derived mesenchymal stem cells (BMSCs); (3) adipose-derived mesenchymal stem cells (ADSCs); and (4) amniotic-derived mesenchymal stem cells (AMSCs). We assessed the following: (1) study methodologies; (2) cell preparations and formulations; (3) patient-reported outcome scores (PROMs); and (4) structural changes. METHODS: PubMed, Cochrane Library, and Embase databases were queried (2013-2021) to conduct a systematic review of biologic therapies for knee OA, according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eighty-two studies were included: PRP (51); BMSC (15); ADSC (11); and AMSC (5). Study evaluations were made using the Modified Coleman Methodology Score. PROMs included the Western Ontario and McMaster Universities Arthritis Index and the Visual Analog Scale. Structural change evaluations included ultrasounds, radiographs, or magnetic resonance imaging. RESULTS: PRP comprised a majority of the studies (n = 51), most with "fair" to "good" Modified Coleman Methodology Score. Studies had variable cell preparations and formulations, with comparison study results leading to inconsistent PROMs, and structural changes. A limited number of studies were included for BMSC, ADSC, and AMSC, all with similar findings to PRP. CONCLUSION: Available literature evaluating "orthobiologics" for knee OA remain nonsuperior to comparison cohorts. Higher level studies with larger sample sizes and improved methodologies are warranted to suggest differences. Despite a growth of "orthobiologics" in clinics, this updated systematic review highlights the uncertain efficacy for use in knee OA.

Low Wear at 10-Year Follow-Up of a Second-Generation Highly Cross-Linked Polyethylene in Total Hip Arthroplasty.

BACKGROUND: Characterizations and factors influencing longer term performance of second-generation sequentially irradiated and annealed highly cross-linked polyethylene (HXLPE) are lacking. We evaluated patients who underwent total hip arthroplasty with HXLPE at mean 10-year follow-up for (1) linear and volumetric wear rates, (2) patient and implant characteristics, (3) implant survivorships, and (4) functional scores. METHODS: We evaluated 130 hips (110 patients) that received HXLPE acetabular liners at a single center. The mean age was 56 years (range, 20-79 years), with a mean follow-up of 10 years (range, 8-15). Radiographic linear (millimeters/year) and volumetric (cubic millimeters/year) wear rates were quantified using radiographic analysis. Survivorship was assessed by all-cause and wear-related revision rates. Functional outcomes were assessed by Short Form 12 and modified Harris Hip Scores. RESULTS: The mean linear wear rate was 0.02 ± 0.03 mm/y, and the mean volumetric wear rate was 12.6 ± 5.3 mm3/y. Younger age had higher volumetric wear (total and yearly, P = .01). Increasing body mass index trended toward higher total and yearly linear (both, P ≤ .09) and volumetric wear (both, P ≤ .07). Ten patients required revisions, with an all-cause survivorship of 92% and a wear survivorship of 100%. The mean modified Harris Hip Scores was 84, and the mean Short Form 12 scores were 46 (physical) and 55 (mental). CONCLUSION: We observed low linear and volumetric wear rates for HXLPE at 10-year mean follow-up. Younger age and higher body mass index at the time of surgery may be important patient characteristics influencing long-term wear. These results illustrate the potential for this second-generation HXLPE to be an appropriate long-term total hip arthroplasty interface.

Social Determinants of Health in Total Hip Arthroplasty: Are They Associated With Costs, Lengths of Stay, and Patient Reported Outcomes?

BACKGROUND: Social determinants of health (SDOH) may play a larger role in predicting patient outcomes as outpatient total hip arthroplasty (THA) expands. We specifically examined the association between SDOH and patient metrics (demographics and comorbidities) for: (1) 30-day post-discharge costs of care; (2) lengths of stay (LOS); and (3) patient-reported outcomes (Hip Disability and Osteoarthritis Outcomes Score for Joints Replacement (HOOS JR)). METHODS: Medicare patients who underwent primary THA between 2018 and 2019 were identified. Those who had complete social determinant data were included (n = 136). Data elements were drawn from institutional, regional, and government databases, as well as the Social Vulnerability Index (SVI). Multiple regression analyses were performed to determine SDOH and baseline comorbidities associations with costs, LOS, and HOOS JR scores. RESULTS: Various SDOH factors were associated with higher 30-day costs, including residing in a food desert ($53,695 ± 15,485; P < .001) and the following SVI themes: 'Minority Status and Language' ($24,075 ± 9845; P = .01) and 'Housing and Transportation' ($16,190 ± 8501; P = .06), although the latter did not meet statistical significance. Baseline depression was associated with longer LOS (P = .02), while none of the other SDOH or patient metrics affected LOS. No relationships were observed between SDOH and HOOS JR changes from baseline. CONCLUSION: Patients who live in food deserts and have minority status had higher costs of care after primary THA. Poor housing and transportation may also increase costs, albeit insignificantly. These results highlight the utility of assessing SDOH-related risk factors to optimize post-operative outcomes, with potential implications for bundled care.

Survival and Outcomes of 1.5-Stage vs 2-Stage Exchange Total Knee Arthroplasty Following Prosthetic Joint Infection.

BACKGROUND: Traditional management of prosthetic joint infection following total knee arthroplasty (TKA) consists of a 2-stage approach. However, 1.5-stage exchange has seen preliminary success, whereby metal femoral and all-polyethylene tibia components are placed without intention for subsequent second stage. We sought to examine all patients who underwent a 1.5-stage exchange TKA at a single institution compared to historical 2-stage controls. We assessed the following: (1) infection-free survivorship and risk factors for reinfection; (2) 1-year surgical/medical outcomes; (3) patient-reported outcomes (ie, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement [KOOS JR]); and (4) radiographic outcomes. METHODS: We reviewed all patients undergoing a 1.5-stage (between 2015 and 2019) and 2-stage exchange TKA (between 2011 and 2016) at a single institution. A total of 162 knees were included (1.5-stage: 114; 2-stage: 48) with mean clinical follow-up of 2.6 years. KOOS JR scores and radiographic outcomes were evaluated at last clinical follow-up. RESULTS: The 1.5-stage exchange TKA resulted in a 10.1% difference in infection-free survival (85.1% vs 75.0%, P = .158), compared to 2-stage exchange. Prior prosthetic joint infection was found to be an independent risk factor for reinfection (P = .030). Overall, postoperative complications were lower among 1.5-stage exchanges (8.8% vs 31.3%, P < .001). KOOS JR scores improved more from baseline among 1.5-staged (Δ24.7 vs Δ16.6, P < .001). Radiographic review did not demonstrate any progressive radiolucent lines, subsidences, or failures in either group. CONCLUSION: A 1.5-stage exchange TKA is an effective alternative to the traditional 2-stage protocols with noninferior infection eradication and absence of radiographic complications at over 2 years of mean follow-up.

Timing and Type of Bariatric Surgery Preceding Total Knee Arthroplasty Leads to Similar Complications and Outcomes.

BACKGROUND: No consensus exists regarding the appropriate timing of bariatric surgery (BS) or the complication profiles between Roux-en-Y Gastric Bypass (RYGB) and sleeve gastrectomy (SG) prior to total knee arthroplasty (TKA). We sought to compare 90-day medical and up to two-year surgical complications and revisions among (1) BS performed 6 months and 1 year prior to TKA; (2) between BS types (RYGB and SG) prior to TKA; and (3) with comparison to 2 non-BS cohorts of morbidly and nonmorbidly obese patients. METHODS: We queried a national database to identify patients undergoing BS (RYGB and SG) prior to TKA from 2010 to 2020. Timing (six-month and one-year intervals) and type of BS (RYGB and SG) were identified. Cohorts without prior BS served as comparators: BMI, kg/m2 > 40 and 20-35. Ninety-day to two-year medical/surgical complications and revisions were assessed. Multivariate regression analyses examined the risk factors for prosthetic joint infections (PJIs) and revisions. RESULTS: The timing of BS (6 months and 1 year) had similar incidences of medical/surgical complications and revisions, with both lower than the BMI > 40 cohort (P < .001). Differences between types of BS were also lower than the BMI > 40 cohort (P < .001). The BMI 20-35 had lower complications and revisions among all cohorts. No differences were observed between BS timing or type as risk-factors for PJIs and revisions. CONCLUSION: Timing (6 months or 1 year prior to TKA) and type of BS shared similar complication profiles, lower than BMI > 40 and higher than BMI 20-35. These findings support a surgeon's decision to proceed with TKA at six months post-BS if indicated.

Neighborhood Socioeconomic Disadvantages Associated With Prolonged Lengths of Stay, Nonhome Discharges, and 90-Day Readmissions After Total Knee Arthroplasty.

BACKGROUND: Low socioeconomic status and neighborhood context has been linked to poor health care outcomes after total knee arthroplasty (TKA). The area deprivation index (ADI) addresses this relationship by ranking neighborhoods by socioeconomic disadvantage. We examined the following relationships of the ADI among TKA recipients: (1) patient demographics, (2) lengths of stay (LOS), (3) nonhome discharges, and (4) 90-day readmissions, emergency department visits, and reoperations. METHODS: We reviewed a consecutive series of primary TKAs from 2018 through 2020 at a tertiary health care system. A total of 3928 patients who had complete ADI data were included. A plurality of patients (14.9%) were categorized within ADI 31-40, below the national median ADI of 47. Associations between the national ADI decile and 90-day postoperative health care utilization metrics were evaluated using multivariate regressions (adjusted for patient demographics and comorbidities). RESULTS: The 91-100 ADI cohort was disproportionately African American, female, younger, and smokers. Compared with ADI 31-40 (reference), the ADI 61-70 cohort was associated with higher odds of LOS ≥3 days (odds ratio [OR] = 1.6 [1.08-2.36], P = .019) and nonhome discharges (OR = 1.73 [1.08-2.75], P = .021). The ADI 91-100 cohort was associated with the highest odds of prolonged LOS (OR = 2.27; [1.47-3.49], P < .001), nonhome discharges (OR = 3.49 [2.11-5.78], P < .001), and all-cause readmissions (OR: 1.79, [1.02-3.14], P = .044). No significant associations were found between the ADI and 90-day emergency department visits or reoperations (P > .05). CONCLUSION: A higher ADI was associated with prolonged LOS, nonhome discharge status, and 90-day readmissions after TKA. This index highlights potential areas of intervention for assessing health care outcomes.

Revision Distal Femoral Replacement for Patello-Femoral Maltracking: A Surgical Technique.

The use of the distal femoral replacement (DFR) has grown in recent years. Historically, this procedure was reserved for malignancy and complex revision cases with relative success. In recent years, complex reconstruction cases have had relative success. DFR has been associated with a range of complications including anterior knee pain, patellar instability, limitations in knee motion, and rotational instability that are sequelae of altered patello-femoral mechanics. Thus, subsequent dysfunction may require revision. To our knowledge, no surgical technique to correct DFR patello-femoral maltracking has been demonstrated in current literature. We present a surgical technique for DFR patello-femoral maltracking corrected surgically with femoral component revision and femoral stem retention.

Tapered Modular Femoral Stems for Revision Total Hip Arthroplasty Show Excellent Mid-Term Survivorship.

INTRODUCTION: Revision total hip arthroplasty (THA) can be challenging in the face of proximal femoral bone loss, catastrophic implant failure, or recurrent hip instability. Tapered modular femoral stems have shown substantial success at short follow up for aseptic revisions. The purpose of this study was to report mid-term revision THA outcomes of a tapered modular femoral stem at a tertiary referral center used to treat both aseptic as well as periprosthetic joint infections (PJIs). We specifically sought to assess: (1) revision-free implant survivorship; (2) patient-reported outcome measurements (i.e., Hip Disability and Osteoarthritis Outcome Score, Joint Replacement [HOOS JR]); (3) postoperative surgical complications and 30-day readmissions; as well as (4) radiographic outcomes. MATERIALS AND METHODS: We reviewed a consecutive series of 92 patients who underwent revision THA between 2009 and 2013 with a tapered modular femoral stem. After accounting for mortality (n=7) and loss to follow up (n=13), a total of 72 implants in 66 patients who had eight years of mean follow up (range, 2 to 11) were included. PJI (46%) was the predominant preoperative indication for revision THA, followed by aseptic loosening (25%), periprosthetic fracture (18%), and symptomatic hardware (10%). Outcomes of interest included all-cause revision-free survivorship, postoperative complications, and HOOS JR, as well as SF-12 scores. Radiographically, they were evaluated for subsidence, radiolucencies, and loosening. RESULTS: Aseptic revision-free survivorship of the femoral component was 95.8% (69 out of 72). Including septic cases, revision-free survivorship was 87.5% (63 cases), and 60 implants (83.3%) had an all-cause revision-free survivorship. For those patients who underwent septic revisions, eight out of nine remained infection free, while one underwent a resection arthroplasty. Furthermore, the cause for femoral aseptic revisions were subsidence (1.4%) and aseptic loosening (2.8%). Functional score improvements for HOOS JR, SF-12 PCS, as well as MCS were 29, 13, and 2, respectively (all p<0.001). There were eight emergency department visits (11.1%,) and six inpatient readmissions (8.3%). Additionally, two patients had dislocations (2.8%, two out of 72) not requiring revision. There were two cases of femoral subsidence and one aseptic loosening requiring revision; whereas, the rest did not demonstrate any progressive radiographic lucencies. DISCUSSION: The eight-year mean survivorship results of the tapered modular femoral stems in revision THA demonstrated excellent results. Our series found improved outcome scores and relatively low postoperative complications, which indicate a favorable implant survivorship profile for revision THA. CONCLUSION: These results serve to inform arthroplasty surgeons of expected outcomes of the modular stems when used for patients who need complex revision THA.

THAs Performed Within 6 Months of Clostridioides difficile Infection Are Associated with Increased Risk of 90-Day Complications.

BACKGROUND: Clostridioides difficile infection (CDI) may be a surrogate for poor patient health. As such, a history of CDI before THA may be used to identify patients at higher risk for postoperative CDI and complications after THA. Investigations into the associations between CDI before THA and postoperative CDI and complications are lacking. QUESTIONS/PURPOSES: We compared the (1) frequency and potential risk factors for CDI after THA, (2) the frequency of 90-day complications after THA in patients with and without a history of CDI, and (3) the length of stay and frequency of readmissions in patients experiencing CDIs more than 6 months before THA, patients experiencing CDIs in the 6 months before THA, and patients without a history of CDI. METHODS: Patients undergoing primary THA from 2010 to 2019 were identified in the PearlDiver database using ICD and Current Procedural Terminology codes (n = 714,185). This analysis included Medicare, Medicaid, and private insurance claims across the United States with the ability to perform longitudinal and costs analysis using large patient samples to improve generalizability and reduce error rates. Patients with a history of CDI before THA (n = 5196) were stratified into two groups: those with CDIs that occurred more than 6 months before THA (n = 4003, median 2.2 years [interquartile range 1.2 to 3.6]) and those experiencing CDIs within the 6 months before THA (n = 1193). These patients were compared with the remaining 708,989 patients without a history of CDI before THA. Multivariable logistic regression was used to evaluate the association of risk factors and incidence of 90-day postoperative CDI in patients with a history of CDI. Variables such as antibiotic use, proton pump inhibitor use, chemotherapy, and inflammatory bowel disease were included in the models. Chi-square and unadjusted odds ratios with 95% confidence intervals were used to compare complication frequencies. A Bonferroni correction adjusted the p value significance threshold to < 0.003. RESULTS: Prior CDI during either timespan was associated with higher unadjusted odds for postoperative CDI (CDI > 6 months before THA: OR 8.44 [95% CI 6.95 to 10.14]; p < 0.001; CDI ≤ 6 months before THA: OR 49.92 [95% CI 42.26 to 58.54]; p < 0.001). None of the risk factors included in the regression were associated with increased odds for postoperative CDI in patients with preoperative history of CDI. Patients with a history of CDI before THA were associated with higher unadjusted odds for every 90-day complication compared with patients without a history of CDI before THA. CDI during either timespan was associated with longer lengths of stay (no CDI before THA: 3.8 days; CDI > 6 months before THA: 4.5 days; CDI ≤ 6 months before THA: 5.3 days; p < 0.001) and 90-day readmissions (CDI > 6 months before THA: OR 2.21 [95% CI 1.98 to 2.47]; p < 0.001; CDI ≤ 6 months before THA: OR 3.39 [95% CI 2.85 to 4.02]; p < 0.001). CONCLUSION: Having CDI before THA was associated with higher odds of postoperative CDI compared with patients without a history of CDI. A history of CDI within the 6 months before THA was associated with the greatest odds for postoperative complications and readmissions. Providers should strongly consider delaying THA until 6 months after CDI, if possible, to provide adequate time for patient recovery and eradication of infection. LEVEL OF EVIDENCE: Level III, therapeutic study.

Osteoarthritis and Osteonecrosis in Total Hip Arthroplasty: 90-Day Postoperative Costs and Outcomes.

BACKGROUND: Two common diagnoses for patients undergoing total hip arthroplasty (THA) are osteoarthritis (OA) and osteonecrosis (ON), pathologically different diseases that affect postoperative complication rates. The underlying pathology of ON may predispose patients to a higher rate of certain complications. Previous research has linked ON with higher mortality and revisions, but a comparison of costs and complication rates may help elucidate further risks. This study reports 90-day costs, lengths of stay (LOS), readmission rates, and complication rates between patients undergoing THA for OA and ON. METHODS: The Nationwide Readmissions Database was retrospectively reviewed for primary THAs, with 90-day readmissions assessed from the index procedure. Patients diagnosed with OA (n = 1,577,991) and ON (n = 55,034) were identified. Costs, LOS, and any readmission within 90 days for complications were recorded and analyzed with the chi-square and t-tests. RESULTS: Patients with ON had higher 90-day costs ($20,110.80 vs. 22,462.79, P < .01) and longer average LOS (3.48 vs. 4.49 days, P < .01). Readmission rates within 90 days of index THA were significantly higher among patients with ON (7.7% vs. 13.1%, P < .01). Patients with OA had a lower incidence of 90-day overall complications (4.1 vs. 6.4%, P < .01). CONCLUSIONS: Patients undergoing THA for ON incur higher readmission-related costs and complication rates. Understanding the predisposing factors for increased complications in ON may improve patient outcomes.

How Does Conversion Total Hip Arthroplasty Compare to Primary?

BACKGROUND: Recent institutional evidence suggests that conversion total hip arthroplasty (THA) incurs higher complication rates and costs when compared to primary THA. These findings contrast with the current reimbursement system as conversion and primary THAs are classified under the same diagnosis-related group. Thus, a national all-payer database was utilized to compare complication rates up to 2 years, 30-day readmission rates, and 90-day costs between conversion THA and matched primary THA patients. METHODS: A retrospective review of the PearlDiver database between 2010 and second quarter of 2018 was performed using Current Procedural Terminology (CPT) codes to compare conversion THA (CPT 27132) to primary THA (CPT 27130). Patients were matched at a 1:3 ratio based on age, gender, Charlson Comorbidity Index, body mass index, tobacco use, and diabetes (conversion = 8369; primary = 25,081 patients). RESULTS: Conversion THA had higher rates of periprosthetic joint infections (conversion: 7.7% vs primary: 1.4%), hip dislocations (4.5% vs 2.0%), blood transfusions (2.0% vs 1.0%), mechanical complications (5.5% vs 1.0%), and revision surgeries (4.0% vs 1.5%) (P < .001 for all) by 90 days. The 30-day readmission rate for conversion THA was significantly higher compared to the primary group (7.3% vs 3.3%) (P < .001). Median cost at 90 days for conversion THA was significantly higher compared to primary THA ($18,800 vs $13,611, P < .001). CONCLUSION: This study revealed increased complication rates, revisions, readmissions, and costs among conversion THA patients compared to matched primary THA patients. These results support the reclassification of conversion into a diagnosis-related group separate from primary THA.

Endplate volumetric bone mineral density measured by quantitative computed tomography as a novel predictive measure of severe cage subsidence after standalone lateral lumbar fusion.

PURPOSE: Quantitative computed tomography (QCT) is an alternate imaging method to dual X-ray absorptiometry to measure bone mineral density (BMD). One advantage of QCT is that it allows site-specific volumetric BMD (vBMD) measurements in a small region. In this study, we utilized site-specific, endplate vBMD (EP-vBMD) as a potential predictive marker of severe cage subsidence in standalone lateral lumbar interbody fusion (SA-LLIF) patients and conducted a retrospective comparative study between EP-vBMD and trabecular vBMDs (Tb-vBMD) in the vertebrae. METHODS: Patients undergoing SA-LLIF from 2007 to 2016 were retrospectively reviewed. EP-vBMD was defined as the average of the upper and lower endplate volumetric BMDs measured in cortical and trabecular bone included in a 5-mm area of interest beneath the cage contact surfaces. We compared Tb-vBMDs and EP-vBMDs between disk levels that had severe cage subsidence and levels with no severe subsidence. RESULTS: Both EP-vBMD and Tb-vBMD could be measured in 210 levels of 96 patients. Severe cage subsidence was observed in 58 levels in 38 patients. Median (IQR) Tb-vBMD was 120.5 mg/cm3 (100.8-153.7) in the non-severe subsidence group and 117.9 mg/cm3 (90.6-149.5) in the severe subsidence group (p = 0.393), whereas EP-vBMD was significantly lower in the severe subsidence group than the non-severe subsidence group (non-severe subsidence 257.4 mg/cm3 (216.3-299.4), severe subsidence 233.5 mg/cm3 (193.4-273.3), p = 0.026). CONCLUSION: We introduced a novel site-specific vBMD measurement for cage subsidence risk assessment. Our results showed that EP-vBMD was a reproducible measurement and appeared more predictive for severe cage subsidence after SA-LLIF than Tb-vBMD. These slides can be retrieved under Electronic Supplementary Material.