Continuing Home Oral Hypoglycemic Medications Was Associated With Superior Postoperative Glycemic Control Versus Initiating Sliding Scale Insulin After Total Hip Arthroplasty.

BACKGROUND: This retrospective study investigated the impact of continuing vs discontinuing home oral hypoglycemic medications for patients with diabetes undergoing total hip arthroplasty. MATERIALS AND METHODS: Patients who were not exclusively receiving home oral hypoglycemic regimens were excluded. Additionally, patients whose diabetes was not managed inpatient postoperatively were excluded. Included patients were retrospectively evaluated for early postoperative glycemic control, renal function, and metabolic abnormalities. Patients were then compared based on whether their home oral hypoglycemic regimen was continued vs discontinued in favor of initiating insulin while inpatient and analyzed using multivariable regression analysis. RESULTS: A total of 532 patients undergoing total hip arthroplasty met inclusion criteria, with 78.6% continuing their home oral hypoglycemic regimen. Those who continued showed significantly lower median maximum inpatient blood glucose (178.5 mg/dL vs 249.5 mg/dL; P<.001) and median average inpatient blood glucose (138.4 mg/dL vs 178.6 mg/dL; P<.001). Linear regression analysis, adjusting for various potential confounding factors, revealed a positive correlation between discontinuation of home hypoglycemic medications and higher maximum in-patient blood glucose (ß=70.15 [95% CI, 59.27-81.03]; P<.001). Patients in the continuation group had lower proportions of acute kidney injury (18.7% vs 41.2%; P<.001) and metabolic acidosis (4.3% vs 17.5%; P<.001), along with a shorter length of stay (1.0 d vs 2.0 d; P<.001). CONCLUSION: These findings suggest that continuing a home oral hypoglycemic regimen for patients with diabetes after total hip arthroplasty is associated with superior glycemic control without exacerbating renal abnormalities or increasing metabolic complications. [Orthopedics. 202x;4x(x):xx-xx.].

Unsuspected Positive Intraoperative Cultures in Aseptic Revision Knee Arthroplasty: Prevalence, Management, and Infection-Free Survivorship.

BACKGROUND: The purpose of this study was to evaluate the management and outcomes of aseptic revision total knee arthroplasty (arTKA) with unsuspected positive cultures (UPCs) compared to those with sterile cultures. METHODS: The institutional database at a single tertiary center was retrospectively reviewed for arTKA from January 2013 to October 2023. Patients who met Musculoskeletal Infection Society (MSIS) criteria for periprosthetic infection (PJI) based on available preoperative infectious workup, received antibiotic spacers, or did not have at least 1 year of follow-up were excluded. Patients were stratified based on intraoperative cultures into 4 cohorts: sterile cultures, 1 UPC, ≥ 2 UPCs with different organisms, and ≥ 2 UPCs with the same organism. Univariable analyses were used to compare these groups. Kaplan-Meyer survivorship analysis assessed infection-free survival at 5 years, and Cox proportional hazards regressions were used to evaluate factors that influence infection-free survival. A total of 691 arTKAs at a mean follow-up of 4.2 years were included in the study. Of these, 49 (7.1%) had 1 UPC with a new organism, 10 (1.4%) had ≥ 2 UPCs of the same organism, and 2 (0.2%) had ≥ 2 UPCs with different organisms. RESULTS: Postoperative antibiotics were prescribed to 114 (16.5%) patients - 13 (26.5%) with 1 UPC, 6 (60.0%) with ≥ 2 UPCs of the same organism, and 0 (0.0%) of patients who had ≥ 2 UPCs of different organisms. There were no differences in infection-free survival at 5 years between patients who had sterile cultures and 1 UPC (96 versus 89%; P = 0.39) nor between sterile cultures and ≥ 2 UPCs of different organisms (96 versus 100%; P < 0.72). However, patients who had ≥ 2 UPCs of the same organism had significantly worse infection-free survival at 5 years compared to patients who had sterile cultures (58 versus 96%; P < 0.001). Cox proportional hazards regression suggested that when adjusting for covariates, an American Society of Anesthesiologists classification of ≥ 3 (hazard ratio [HR] = 3.1; P = 0.007), ≥ 2 UPCs of the same organism (HR = 11.0; P < 0.001), 1 UPC (HR = 4.2; P = 0.018), and arTKA with hinge constructs (HR = 4.1; P = 0.008) were associated with increased risk of re-revision for PJI. CONCLUSION: Patients who had 1 UPC or ≥ 2 UPCs with different organisms had similar infection-free survival at 5 years as patients who had sterile cultures. However, patients who had ≥ 2 UPCs of the same organism had significantly worse infection-free survival at five years. Overall, 1 UPC or ≥ 2 UPCs of the same organism at the time of arTKA may suggest the patient is at higher risk of re-revision for PJI. More studies are needed to determine what interventions can be implemented to mitigate this risk.

Mixed Reality Navigation in Hip Fusion Conversion: A Novel Utilization of Advanced Technology: A Case Report.

CASE: A 32-year-old woman with a history of hip fusion presented with significant lower back, hip, and knee pain as well as severely limited hip mobility and function. Single-stage fusion takedown and conversion to total hip arthroplasty (THA) was performed using augmented reality navigation. At 1 year, the patient was pain free with improved function. This study is the first to report the technique and outcomes of surgical fusion conversion to THA, using mixed reality navigation. CONCLUSION: Mixed reality navigation in complex conversion THA can be useful for identifying the patient's true acetabulum and for patient-specific acetabular component placement to maximize outcomes.

Risk Factors of Failure to Discharge Before "Two Midnights" in Outpatient-Designated Total Hip Arthroplasty.

INTRODUCTION: The Centers for Medicare and Medicaid Services removed total hip arthroplasty (THA) from the inpatient-only list but continued to classify admissions as inpatient if they include two midnights, complicating care if an outpatient THA requires extended hospitalization. This study evaluates risk factors of patients undergoing outpatient-designated THA with a length of stay (LOS) ≥ 2 days. METHODS: A total of 17,063 THA procedures designated as outpatient in the National Surgical Quality Improvement Program database between 2015 and 2020 were stratified by LOS < 2 days (n = 2,294, 13.4%) and LOS ≥ 2 days (n = 14,765, 86.6%). Demographics, comorbidities, and outcomes were compared by univariate analysis. Multivariable regression analysis identified predictors of LOS ≥ 2 days. RESULTS: Outpatients with extended LOS were older (mean 65.3 vs. 63.5 years; P < 0.01); were more likely to have body mass index (BMI) > 35 (24.0 vs. 17.8%; P < 0.01); and had higher incidences of smoking (15.1% vs. 10.3%; P < 0.01), diabetes (15.4% vs. 9.9%; P < 0.01), chronic obstructive pulmonary disease (4.4% vs. 2.3%; P < 0.01), and hypertension (57.6% vs. 49.2%; P < 0.01). Patients with LOS ≥ 2 days had a higher incidence of surgical site infection (P < 0.01), hospital readmission (P < 0.01), and revision surgery (P < 0.01) over 30 days. Multivariable analysis demonstrated advanced age, female sex, African American race, Hispanic ethnicity, diabetes, smoking, and hypertension were independent risk factors for LOS ≥ 2 days. CONCLUSION: Despite removal from the inpatient-only list, a subset of outpatient THA remains at risk of an extended LOS. This study informs surgeons on the relevant risk factors of extended stay, enabling early inpatient preauthorization.

The relationship between pseudotumours and infected complications in patients who have undergone metal-on-metal total hip arthroplasty.

Aims: This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection. Methods: A total of 1,171 total hip arthroplasty (THA) patients with MoM articulations from August 2000 to March 2014 were retrospectively identified. Of those, 328 patients underwent metal artefact reduction sequence MRI and had minimum two years' clinical follow-up, and met our inclusion criteria. Data collected included demographic details, surgical indication, laterality, implants used, history of pseudotumour, and their corresponding preoperative ESR (mm/hr) and CRP (mg/dl) levels. Multivariate logistic regression modelling was used to evaluate PJI and history of pseudotumour, and receiver operating characteristic curves were created to assess the diagnostic capabilities of ESR and CRP to determine the presence of infection in patients undergoing revision surgery. Results: The rate of PJI for all identified MoM THAs was 3.5% (41/1,171), with a mean follow-up of 10.9 years (2.0 to 20.4). Of the patients included in the final cohort, 8.2% (27/328) had PJI, with a mean follow-up of 12.2 years (2.3 to 20.4). Among this cohort, 31.1% (102/328) had a history of pseudotumour. The rate of PJI in these patients was 14.7% (15/102), which was greater than those without pseudotumour, 5.3% (12/226) (p = 0.008). Additionally, logistic regression analysis showed an association between history of pseudotumour and PJI (odds ratio 4.36 (95% confidence interval 1.77 to 11.3); p = 0.002). Optimal diagnostic cutoffs for PJI in patients with history of pseudotumour versus those without were 33.1 mm/hr and 24.5 mm/hr for ESR and 7.37 mg/dl and 1.88 mg/dl for CRP, respectively. Conclusion: Patients with history of pseudotumour secondary to MoM THA had a higher likelihood of infection than those without. While suspicion of infection should be high for these patients, ESR and CRP cutoffs published by the European Bone and Joint Infection Society may not be appropriate for patients with a history of pseudotumour, as ESR and CRP levels suggestive of PJI are likely to be higher than for those without a pseudotumour. Additional investigation, such as aspiration, is highly recommended for these patients unless clinical suspicion and laboratory markers are low.

Enhanced Total Hip Arthroplasty Education Using Augmented Reality: A Survey From a Tertiary Center.

BACKGROUND: For total hip arthroplasty (THA), a new technology in the evolution of computer-assisted surgery has emerged in the form of augmented reality (AR). We sought to determine the impact of AR on resident and fellow education after implementation at an academic teaching center. MATERIALS AND METHODS: The senior author's intraoperative technique allows for the orthopedic trainee to use AR to correct the acetabular component's position after an attempt is made with standard instrumentation. One year after the implementation of this AR method, both resident and fellow trainees were issued an anonymous survey regarding their experience and descriptive statistics were calculated for the results. RESULTS: Sixteen trainees responded to the survey. One hundred percent felt the use of AR improved their understanding of acetabular component placement and improved their intraoperative experience. Sixty-nine percent reported feeling there was a small increase in operative time but 25% reported no increase in operative time when using AR. Seventy-five percent of trainees felt that patients benefited from the technology and would be in favor of AR if they were having a THA. The majority of those surveyed reported a desire to use AR in their practice if it is available. CONCLUSION: Computer-assisted surgery has demonstrated variable impacts on orthopedic education. After the implementation of AR at an academic teaching center, all trainees reported it improved their intraoperative experience and their understanding of acetabular component placement. Further studies are needed to determine if AR is able to improve a trainee's component placement. [Orthopedics. 202x;4x(x):xx-xx.].

Total Joint Arthroplasty Is a Viable Treatment Option for Patients With Osteonecrosis and Osteoarthritis After Bone Marrow Transplantation.

Background: Long-term survival in patients who receive bone marrow transplantation (BMT) is increasing. However, osteonecrosis and secondary osteoarthritis (OA) of the hip and knee are common complications in this population due to post-transplant steroid treatment to prevent graft vs host disease. The purpose of this study was to evaluate the outcomes of total joint arthroplasty (TJA) in patients with prior BMT and compare them to those of patients undergoing TJA for primary OA. Methods: Patients with a history of BMT undergoing primary TJA from 2013 to 2021 were retrospectively reviewed. Patients were matched 1:1 by surgical site, sex, age, body mass index, American Society of Anesthesiologists score, and Elixhauser Comorbidity Index to patients undergoing TJA for primary OA. Demographics, intraoperative blood loss, perioperative transfusion requirements, hospital length of stay, 90-day emergency department visits and readmissions, all-cause revisions, and 2-year mortality were compared between cohorts. Results: There were 17 patients undergoing total knee arthroplasty (TKA) after BMT (TKA-BMT) and 43 patients undergoing total hip arthroplasty (THA) after BMT (THA-BMT). More TKA-BMT and THA-BMT patients were immunosuppressed preoperatively compared to 17 matched TKA-OA and 43 THA-OA patients (P = .018 and P < .001). There were no other significant perioperative differences between BMT and OA groups. Two-year patient and implant survivorship for TKA-BMT and THA-BMT patients were high and not statistically different from TKA-OA and THA-OA cohorts. Conclusions: TJA after BMT provides satisfactory perioperative and short-term outcomes and is a viable treatment option for patients with osteonecrosis and secondary OA after BMT treatment.

The Removal of Total Knee Arthroplasty From the Inpatient-Only List has Improved Patient Optimization.

INTRODUCTION: On January 1, 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only (IPO) list, expanding outpatient TKA (oTKA) to include patients with insurance coverage through their programs. These regulatory changes reinforced the need for preoperative optimization to ensure a safe and timely discharge after surgery. This study compared modifiable preoperative optimization metrics in patients who underwent oTKA pre-IPO and post-IPO removal. The authors hypothesized that patients post-IPO removal would demonstrate improvement in the selected categories. METHODS: Outpatient TKA in a national database was identified and stratified by surgical year (2015 to 2017 versus 2018 to 2020). Preoperative optimization thresholds were established for the following modifiable risk factors: albumin, hematocrit, sodium, smoking, and body mass index. The percentage of patients who did not meet thresholds pre-IPO and post-IPO removal were compared. RESULTS: In total, 2,074 patients underwent oTKA from 2015 to 2017 compared with 46,480 from 2018 to 2020. Patients undergoing oTKA after IPO removal were significantly older (67.0 versus 64.4 years; P < 0.01). A lower percentage of patients in the post-IPO cohort fell outside the threshold for all modifiable risk factors. Results were significant for preoperative sodium (10.7% versus 8.8%; P < 0.01), body mass index (12.4% versus 11.0% P = 0.05), and smoking history (9.9% versus 6.6%; P < 0.01). CONCLUSION: Outpatient TKA has increased considerably post-IPO removal. As this regulatory change has allowed older patients with increased comorbidities to undergo oTKA, the need for appropriate preoperative optimization has increased. The current data set demonstrates that surgeons have improved preoperative optimization efforts for select modifiable risk factors.

The Posterior Approach is Associated With Lower Total Encounter and 90-Day Costs When Compared to the Direct Anterior Approach.

BACKGROUND: The clinical impact of the surgical approach in total hip arthroplasty (THA) has been widely reviewed. This study evaluated the total encounter and 90-day costs of THA for 2 surgical approaches (posterior [P] and direct anterior [DA]) in 1 tertiary health system. METHODS: This is a retrospective review of 2,101 THAs (1,092 P and 1,009 DA) by 4 surgeons (2 with the highest volume of DA and P, respectively) from 2017 to 2022 at 1 academic center. Demographics, comorbidities, operative time, length of hospital stay, 90-day hospital returns, and complications were compared. The total encounter cost and 90-day postoperative cost were itemized. Multivariable regression analyses evaluated associations with increased cost at each time point. RESULTS: The DA cohort had a higher median encounter cost ($8,348.66 versus 7,332.42, P < .01), resulting from higher intraoperative (P < .01) and radiology (P < .01) expenses. Regression analyses demonstrated the DA was independently associated with increased encounter costs (odds ratio 1.1; 95% confidence interval 1.1 to 1.1; P < .01). There was a higher incidence of 90-day emergency department visits in the DA cohort (16 versus 12%, P = .02), with a trend toward increased readmissions. There was no difference in 90-day reoperations. Median 90-day cost was higher in the DA cohort ($126.99 versus 0.00, P < .01), and regression analyses demonstrated the DA had an association with increased 90-day cost (odds ratio 2.2; 95% confidence interval 1.5 to 3.0; P < .01). CONCLUSIONS: Despite a younger patient population, the DA was independently associated with increased encounter and 90-day costs in a single academic hospital system. This study may underestimate the cost difference, as capital costs such as specialized tables were not analyzed.

Timing of Renal Transplant Prior to Total Knee Arthroplasty Impacts 90-Day Postoperative Outcomes.

BACKGROUND: Renal transplant (RT) patients are at increased risk for complications after total knee arthroplasty (TKA); however, it is unknown if the time from RT to TKA influences such risks. This study evaluated RT patients undergoing primary TKA at various time intervals after transplant. We hypothesized that increased time between RT and TKA would decrease the risk of complications after TKA. METHODS: There were 499 RT patients in a national database undergoing subsequent primary TKA from 2010 to 2020. Patients were stratified by intervals of less than 1 year, between 1 and 2 years, and more than 2 years from RT to TKA. Medical complications up to 90 days, readmissions, and 2-year revisions were compared via univariable and multivariable analyses. RESULTS: Patients who underwent TKA less than 1 year after RT were associated with higher 90-day medical complications when compared to those who underwent TKA 1 to 2 years after RT (odds ratio [OR] 0.4, confidence interval [CI] 0.2 to 0.8, P = .01) and more than 2 years (OR 0.3, CI 0.2 to 0.7, P < .01) after RT. Acute kidney injury and blood transfusion were the most common complications. The TKAs performed 2 years after RT were less likely to have 90-day readmissions when compared to TKAs performed less than 1 year after RT (OR 0.4, CI: 0.2 to 0.9, P < .01). However, time from RT to TKA did not increase the risk of revision at 2 years (P > .30). CONCLUSIONS: Patients undergoing TKA within 1 year of RT have an increased risk of 90-day postoperative medical complications and readmissions, but the time interval from RT does not appear to affect revision risk. These findings suggest waiting 1 year after RT before proceeding with TKA may be advantageous.

Continuation of Oral Antidiabetic Medications Was Associated With Better Early Postoperative Blood Glucose Control Compared to Sliding Scale Insulin After Total Knee Arthroplasty.

BACKGROUND: This study evaluated blood glucose (BG), creatinine levels, metabolic issues, length of stay (LOS), and early postoperative complications in diabetic primary total knee arthroplasty (TKA) patients. It examined those who continued home oral antidiabetic medications and those who switched to insulin postoperatively. The hypothesis was that continuing home medications would lead to lower BG levels without metabolic abnormalities. METHODS: Patients who had diabetes who underwent primary TKA from 2013 to 2022 were evaluated retrospectively. Diabetic patients who were not on home oral antidiabetic medications or who were not managed as an inpatient postoperatively were excluded. Patient demographics and laboratory tests collected preoperatively and postoperatively as well as 90-day emergency department visits and 90-day readmissions, were pulled from electronic records. Patients were grouped based on inpatient diabetes management: continuation of home medications versus new insulin coverage. Acute postoperative BG control, creatinine levels, metabolic abnormalities, LOS, and early postoperative complications were compared between groups. Multivariable regression analyses were performed to measure associations. RESULTS: A total of 867 primary TKAs were assessed; 703 (81.1%) patients continued their home oral antidiabetic medications. Continuing home antidiabetic medications demonstrated lower median maximum inpatient BG (180.0 mg/dL versus 250.0 mg/dL; P < .001) and median average inpatient BG (136.7 mg/dL versus 173.7 mg/dL; P < .001). Logistic regression analyses supported the presence of an association (odds ratio = 17.88 [8.66, 43.43]; P < .001). Proportions of acute kidney injury (13.5 versus 26.7%; P < .001) were also lower. There was no difference in relative proportions of metabolic acidosis (4.4 versus 3.7%; P = .831), LOS (2.0 versus 2.0 days; P = .259), or early postoperative complications. CONCLUSIONS: Continuing home oral antidiabetic medications after primary TKA was associated with lower BG levels without an associated worsening creatinine or increase in metabolic acidosis. LEVEL III EVIDENCE: Retrospective Cohort Study.

A Cost Analysis of Surgical Approach in Total Hip Arthroplasty.

BACKGROUND: With pressures to decrease the financial burden of total hip arthroplasty (THA), it is imperative to understand the cost drivers of this procedure. This study evaluated operative and total encounter costs for two surgical approaches to THA-posterior (P) and direct anterior (DA). MATERIALS AND METHODS: A total of 233 THAs (134 P and 99 DA) performed by two fellowship-trained arthroplasty surgeons from 2017 to 2022 were reviewed. Demographics, comorbidities, mobility status, operative time, length of stay, implants used, discharge location, and complications until final follow-up were recorded. Total encounter cost was collected and itemized. Multivariable regression analyses evaluated predictors of cost. RESULTS: There were differences in age (67 years for DA and 63 years for P; P=.03), body mass index (28.0 kg/m2 for DA and 33.8 kg/m2 for P; P<.01), Elixhauser Comorbidity Index score (4.6 for DA and 5.6 for P; P=.04), and operative time (2.1 hours for DA and 1.9 hours for P; P<.01) between the two cohorts. The DA cohort trended toward shorter length of stay, with the highest percentage of patients discharged home (86.9%; P=.02). The P cohort had the lowest encounter ($9601 for DA and $9100 for P; P=.20) and intraoperative (including implant used) ($7268 for DA and $6792 for P; P<.01) costs. The DA cohort had a significantly higher cost of radiology during the encounter ($244; P<.01). Regression analysis demonstrated that length of stay and DA approach were both predictors of increased encounter cost. CONCLUSION: The DA cohort had improved measures of health; however, this approach was associated with a higher operative cost and was predictive of increased encounter cost despite a shorter length of stay. [Orthopedics. 2024;47(3):e151-e156.].

Ultracongruent Polyethylene Liners Do Not Affect Survival of Total Knee Arthroplasty for Valgus Deformity.

BACKGROUND: Valgus knee deformity is observed in nearly 10% of patients undergoing total knee arthroplasty (TKA). The degree of polyethylene constraint required to balance a valgus knee remains controversial, and historically, posterior-stabilized (PS) designs have been favored. This study evaluated the survivorship of TKA done in valgus knees based on implant design and specifically compared posterior-stabilized (PS) and ultracongruent (UC) liners. METHODS: A total of 549 primary TKAs performed on valgus knees by fellowship-trained arthroplasty surgeons from 2013 to 2019 were reviewed. Demographics, comorbidities, degrees of preoperative deformity, implants used, and all-cause revisions until final follow-up were recorded. Cox regression analyses evaluated survival to all-cause revision in each cohort. The mean follow-up was 4.9 years (range, 2 to 9). RESULTS: There were 403 UC liners compared to 146 PS liners. There was no difference in patient age (68 versus 67 years; P = .30), body mass index (30.9 versus 30.4; P = .36), or degree of deformity (8.6 versus 8.8 degrees; P = .75) between the cohorts. At final follow-up, there were 5 revisions in the PS cohort (3.4%) versus 11 revisions in the UC cohort (2.7%) (P = .90). The most common reason for revision in both cohorts was periprosthetic joint infection (4 PS; 8 UC). Multivariable regression analyses controlling for age, body mass index, Elixhauser comorbidity score, sex, and degree of deformity demonstrated UC polyethylene liners were not associated with revision (hazard ratio 0.76; 95% confidence interval [CI] 0.26 to 2.21; P = .62). There was no difference in eight-year survivorship to all-cause revision, including aseptic and septic failure. CONCLUSIONS: Alternative polyethylene liners from the historically utilized PS liners for TKA for valgus deformity did not reduce survivorship. With modern polyethylene designs, UC inserts can be utilized for this deformity without increasing the risk of failure.

Femoral Component Design Is Associated With the Risk of Periprosthetic Femur Fracture After Cementless THA in Patients 65 Years or Older.

BACKGROUND: Periprosthetic femur fracture is a known complication after THA. The associated risk of cementless femoral component design for periprosthetic femur fracture in a registry population of patients older than 65 years has yet to be clearly identified. QUESTIONS/PURPOSES: (1) Is femoral stem geometry associated with the risk of periprosthetic femur fracture after cementless THA? (2) Is the presence or absence of a collar on cementless femoral implant designs associated with the risk of periprosthetic femur fracture after THA? METHODS: We analyzed American Joint Replacement Registry data from 2012 to March 2020. Unique to this registry is the high use of cementless femoral stems in patients 65 years and older. We identified 266,040 primary cementless THAs during the study period in patients with a diagnosis of osteoarthritis and surgeries linked to supplemental Centers for Medicare and Medicaid data where available. Patient demographics, procedure dates, and reoperation for periprosthetic femur fracture with revision or open reduction and internal fixation were recorded. The main analysis was performed comparing the Kheir and Chen classification: 42% (112,231 of 266,040) were single-wedge, 22% (57,758 of 266,040) were double-wedge, and 24% (62,983 of 266,040) were gradual taper/metadiaphyseal-filling cementless femoral components, which yielded a total of 232,972 primary cementless THAs. An additional analysis compared cementless stems with collars (20% [47,376 of 232,972]) with those with collarless designs (80% [185,596 of 232,972]). A Cox proportional hazard regression analysis with the competing risk of death was used to evaluate the association of design and fracture risk while adjusting for potential confounders. RESULTS: After controlling for the potentially confounding variables of age, sex, geographic region, osteoporosis or osteopenia diagnosis, hospital volume, and the competing risk of death, we found that compared with gradual taper/metadiaphyseal-filling stems, single-wedge designs were associated with a greater risk of periprosthetic femur fracture (HR 2.9 [95% confidence interval (CI) 2.2 to 3.9]; p < 0. 001). Compared with gradual taper/metadiaphyseal-filling stems, double-wedge designs showed an increased risk of periprosthetic femur fracture (HR 3.0 [95% CI 2.2 to 4.0]; p < 0. 001). Collarless stems showed an increased risk of periprosthetic fracture compared with collared stems (HR 7.8 [95% CI 4.1 to 15]; p < 0. 001). CONCLUSION: If cementless femoral fixation is used for THA in patients 65 years or older, surgeons should consider using gradual taper/metadiaphyseal-filling and collared stem designs because they are associated with a lower risk of periprosthetic femur fracture. Future investigations should compare gradual taper/metadiaphyseal-filling and collared cementless designs with cemented fixation in this population. LEVEL OF EVIDENCE: Level III, therapeutic study.

Risk factors for failure after rotational muscle flap coverage for prosthetic knee infections.

INTRODUCTION: Soft tissue defects are a devastating complication of prosthetic joint infections (PJI) after total knee arthroplasty (TKA). Rotational flaps are commonly utilized to address these defects with variable reports of success. This study aimed to identify predictors of poor outcomes in rotational muscle flap placement after prosthetic knee infections. The authors hypothesized that outcomes may vary based on infecting pathogen and treatment characteristics. METHODS: 44 cases of rotational muscle flaps for prosthetic knee infection were retrospectively evaluated at a tertiary referral hospital from 2007 to 2020. Muscle flap types included 39 medial and four lateral gastrocnemius, and one anterior tibialis. Minimum follow-up was 1 year (median: 3.4 years). Primary outcome was flap-related complications. Secondary outcomes included recurrent infection requiring additional surgery, final joint outcomes, and mortality. RESULTS: One-year complication-free flap survivorship was 83.9%, recurrent infection-free survivorship was 65.7%, and amputation-free survivorship was 79%. Multivariable cox regression revealed that rheumatoid arthritis diagnosis (HR: 3.4; p = .028) and methicillin-resistant Staphylococcus aureus-positive culture (HR: 4.0; p = .040) had increased risk, while Coagulase-negative Staphylococcus infections had reduced risk for recurrent or persistent infection (HR: 0.2; p = .023). Final joint outcome was retained TKA implant in 18 (40.9%), amputation in 15 (34.1%) patients, and definitive treatment with articulating spacer in 10 (22.7%). 5-years survivorship from death was 71.4%. CONCLUSION: Rotational muscle flaps for soft tissue coverage of the knee are often performed in limb salvage situations with poor survivorship from flap complications, reinfections, and amputation. When considering surgical options for limb salvage, patients should be counseled on these risks.

Inferior Outcomes for Patients Transferred Between Surgical Stages for Knee Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infection (PJI) in total knee arthroplasty may result in 2-stage revision surgery. There are limited data describing outcomes when the first stage is completed at an outside hospital and the patient is referred to a tertiary center. We hypothesized that patients have greater success when both surgeries occur at a single center. METHODS: There were 25 knee PJI patients who presented with an antibiotic spacer and had a minimum 2-year follow-up who were retrospectively identified at a single tertiary referral center from 2014 to 2021. A cohort matched for age, sex, body mass index, Elixhauser comorbidity measure, spacer type, infectious organism, and year of surgery was established with patients who had both stages completed at the investigating institution. Modified Delphi success criteria of no subsequent surgery or reinfection with any species were compared. RESULTS: The transferred group demonstrated a treatment success of 40% compared to 84% in the continuous group (P < .01). The transferred group was more likely to have an additional procedure between stages (44 versus 8%, P < .01), with a higher number of surgeries after primary total knee arthroplasty (4.8 versus 3.0, P < .01), between stages (1.4 versus 0.2, P < .01), and after second stage (0.8 versus 0.2, P = .03). The transferred group had longer durations between stages (20.1 versus 7.0 weeks, P < .01). CONCLUSION: Patients who have PJIs transferred between stages demonstrated higher treatment failure. Surgeons should consider transfer early with a goal of continuous management by a single institution.

Does Medically Supervised Weight Loss Prior to Total Knee Arthroplasty Improve Patient-Reported Pain and Physical Function?

BACKGROUND: Weight loss is commonly recommended before total knee arthroplasty (TKA) despite inconsistent evidence for better outcomes. This study sought to examine the impacts of preoperative weight loss on patient-reported and adverse outcomes among TKA patients supervised by a medical weight management clinic. METHODS: This study retrospectively analyzed patients who underwent medical weight management supervision within 18 months before TKA comparing patients who did and did not have clinically relevant weight loss. Preoperative body mass indices, demographics, Patient-Reported Outcomes Measurement Information System physical function and pain interference scores, pain intensity scores, and adverse outcomes were extracted. Multivariable linear regressions were performed to determine if preoperative weight loss correlated with patient-reported outcomes after controlling for confounders. RESULTS: There were 90 patients, 75.6% women, who had a mean age of 65 years (range, 42-82) and were analyzed. There were 51 (56.7%) patients who underwent clinically relevant weight loss with a mean weight loss of 10.4% and experienced no difference in adverse outcomes. Preoperative weight loss predicted significantly improved 3-month postoperative physical function (ß = 15.2 [13.0-17.3], P < .001), but not pain interference (ß = -18.9 [-57.1-19.4], P = .215) or pain intensity (ß = -1.8 [-4.9-1.2], P = .222) scores. CONCLUSION: We found that medically supervised preoperative weight loss predicted improvement in physical function 3 months after TKA. This weight loss caused no major adverse effects. Further research is needed to understand the causal relationships between preoperative weight loss, medical supervision, and outcome after TKA and to elucidate potential longer-term benefits in a larger sample.

Outcome Disparities in Total Knee and Total Hip Arthroplasty among Native American Populations.

BACKGROUND: No prior racial disparities studies in total knee arthroplasty (TKA) and total hip arthroplasty (THA) have specifically evaluated outcomes among American Indian or Alaska Native (AIAN) patients. We hypothesized that AIAN patients have worse outcomes than White patients after controlling for demographics and comorbidities. METHODS: This was a retrospective cohort study comparing White and AIAN patients undergoing primary TKA/THA from 2012-2019 using the American College of Surgeons National Surgical Quality Improvement Program. Race, demographics, and comorbidities were analyzed for correlations with 30-day outcomes and complications using multivariable logistic and linear regression analyses. RESULTS: Comparing 422,215 White and 2,676 AIAN patients, AIAN patients had higher American Society of Anesthesiologist (ASA) classifications, body mass index (BMI), and were younger at the time of surgery. AIAN patients more often stayed inpatient > 2 days (49.4% vs 36.2%, p < 0.001), underwent reoperation (2.1% vs 1.4%, p < 0.01), and were discharged home (91.4% vs 81.7%, p < 0.01). Regression analyses controlling for age, BMI, sex, ASA classification, and functional status found that AIAN race was significantly positively correlated with a length of stay > 2 days (OR 1.6), reoperation (OR 1.4), and discharging home (OR 2.0). CONCLUSION: AIAN patients undergoing TKA/THA present with a greater comorbidity burden compared to White patients and experience multiple worse outcome metrics including increased hospital length of stay and reoperation rates. Interestingly, AIAN patients were more likely to discharge home, representing a unique racial disparity which warrants further study.

Higher Risk of Reoperation after Total Knee Arthroplasty in Young and Elderly Patients.

As outcomes and survivorship improve, total knee arthroplasty (TKA) has expanded into broader age groups. The purpose of this study is to analyze the impact of age on TKA outcomes using the National Surgical Quality Improvement Program (NSQIP) database from 2015 to 2020. Patients were categorized into young (40-49 years), middle (50-79 years), and elderly (80-89 years) groups. Findings reveal notable differences across age groups. The young cohort had the highest BMI, smoking incidence, and steroid use, while the elderly group exhibited a higher prevalence of comorbidities. Young patients experienced shorter hospital stays (p < 0.001) but longer operative times (p < 0.001), and outpatient surgery was most common in the middle age group. Multivariable regression demonstrated that the elderly group faced increased risks of pneumonia (p < 0.001), acute renal failure (p < 0.001), stroke (p < 0.001), cardiac arrest (p < 0.001), and transfusions (p < 0.001), while both young and elderly patients had higher 30-day reoperation risks (youngest cohort, 1.4% and elderly cohort 1.3% (p < 0.001)). In summary, elderly patients undergoing TKA are at the highest risk for medical complications, while young patients are more likely to undergo inpatient surgery, experience reoperations, and have longer operative times. This study underscores the importance of age-specific counseling for TKA patients and contributes valuable insights into the evolving landscape of knee replacement surgery.

Evaluation of anterior translation in total knee arthroplasty utilizing stress radiographs.

BACKGROUND: Flexion instability is a common cause for revision after total knee arthroplasty (TKA); however, little objective criteria exist to determine excessive laxity in flexion. This study sought to determine the reliability of stress radiographs for flexion laxity using manual stress as well as a commercially available flexion stress device, with the hypothesis that a commercially available force device would provide increased translation compared to manual stress, and radiographic measurements would be reproducible. METHODS: Ten patients who previously underwent TKA with non-hinged components were prospectively and consecutively enrolled at a single center to undergo stress radiographs. Three lateral radiographs with the knee at 90° of flexion were obtained for each patient: rest, commercial stress device at 150N, and manual stress. Calibrated radiographs were evaluated by two raters, and inter-rater and intra-rater reliability were determined using intraclass correlation coefficients (ICC). RESULTS: Ten patients (seven female) with mean age 72 (range 55-82) years and average duration from surgery 36 (range 12-96) months were evaluated. The commercial stress device provided significantly less anterior translation than manual stress (- 0.3 mm vs. 3.9 mm; p < 0.01). Two patients reported pain with use of the stress device. Inter-observer reliability of measurements was good for commercial stress (ICC = 0.86) and excellent for manual stress (ICC = 0.94). Eighty-five percent of measurements were within 1 mm between observers. Intra-observer reliability of measurements was good to excellent for both the stress device and manual stress. CONCLUSIONS: Lateral stress radiographs may assist in the objective evaluation of flexion instability. A commercially available product provided less translation than manual stress; however, measurements were reliable and reproducible between observers. Further research is required to correlate translation with stress radiographs to patient outcomes following revision arthroplasty.