Faculty Bibliography

BACKGROUND:Two-stage revisions for chronic periprosthetic joint infections (PJIs) often include antibiotic-loaded cement spacers to control for infection and preserve function. While studies have reported on complications (dislocations, readmissions, and reoperations) after static versus articulating spacer types, there is a paucity of evidence about whether the degree of spacer constraint in articulating spacers affects these complications. This study aims to address a key gap in understanding as to whether the level of spacer constraint affects complications in two-stage revision THA utilizing articulating spacers. QUESTIONS/PURPOSES/OBJECTIVE:(1) Among patients receiving nonconstrained versus constrained articulating antibiotic spacers during first-stage revision THA for PJI, are there differences in major complications, such as dislocation, loosening, periprosthetic fracture, reinfection, and unplanned revisions? (2) After second-stage reimplantation, do patients who received a nonconstrained versus constrained liner during the first stage show differences in the risk of complications, reoperations, and readmissions? METHODS:This is a retrospective review of 539 patients who underwent two-stage revision THA for PJI at a single-specialty, urban academic referral center between July 2011 and March 2023. Of these 539 patients, 72% (388) were excluded for undergoing a full component revision (femoral or acetabular) for any reason before their first stage, 3% (15) for receiving static spacers, and 6% (35) for receiving prefabricated femoral mono-block stems as part of their first stage. Those who underwent only liner exchange were not excluded. The remaining 19% (101 of 539) of patients were included in the final analysis and categorized by degree of liner constraint: 32 were in the nonconstrained group and 69 were in the constrained group. All surgeons included in this study specialize in adult reconstruction and are fellowship trained, and the selected level of constraint was solely based on their routine practice for articulating spacer construct. Baseline characteristics and clinical data, including age, self-reported gender, race, BMI, American Society of Anesthesiologists score, smoking status, surgical history, and perioperative details, were collected. There were no differences in baseline characteristics between the groups except for smoking status. A priori power analysis determined that 150 patients (75 per group) would be needed to detect a statistical difference in the risk of dislocation between groups, assuming a 20% dislocation risk for the constrained group, at a 0.05 alpha level, and 80% power. RESULTS:Between patients receiving nonconstrained versus constrained liners, there were no differences in complications after the first stage of revision. Three percent (1 of 32) of the nonconstrained liners developed dislocations compared with 3% (2 of 69) in the constrained group (relative risk [RR] 1.1 [95% confidence interval (CI) 0.09 to 12.3]; p > 0.99). Three percent (1 of 32) of the nonconstrained group developed periprosthetic fractures compared with 7% (5 of 69) in the constrained group (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). Similarly, 3% (1 of 32) versus 7% (5 of 69) had persistent infection (RR 0.4 [95% CI 0.05 to 3.69]; p = 0.72). One incident of loosening occurred in the constrained group. There were also no differences in spacer revision incidence: 10% (3 of 32) of the nonconstrained group and 10% (7 of 69) of the constrained group underwent an unplanned revision after the first stage (RR 1.0 [95% CI 0.29 to 3.91]; p = 0.91). For the second stage, dislocation was 14% (3 of 21) in the nonconstrained group and 10% (5 of 52) in the constrained group (RR 1.1 [95% CI 0.2 to 5.9]; p > 0.99). When comparing periprosthetic fractures, 10% (2 of 21) of the nonconstrained group developed periprosthetic fractures compared with 4% (2 of 52) in the constrained group (RR 2.2 [95% CI 0.3 to 16.6]; p = 0.78). Nineteen percent (4 of 21) in the nonconstrained group had persistent infection compared with 12% (6 of 52) in the constrained group (RR 1.5 [95% CI 0.39 to 5.74]; p = 0.81). The occurrence of readmission after the second stage was 19% (4 of 21) in the nonconstrained group compared with 15% (8 of 52) in the constrained group (RR 1.1 [95% CI 0.3 to 3.9]; p > 0.99). Twenty-four percent (5 of 21) of patients in the nonconstrained group required a surgery-related emergency department visit compared with 13% (7 of 52) in the constrained group (RR 1.6 [95% CI 0.4 to 5.6]; p = 0.64). The incidence of reoperation was 14% (3 of 21) in the nonconstrained group and 13% (7 of 52) in the constrained group (RR 0.9 [95% CI 0.2 to 3.8]; p > 0.99). CONCLUSION/CONCLUSIONS:Our results indicated no differences in the risk of dislocations, reinfections, reoperations, and readmissions between patients undergoing constrained versus nonconstrained articulating spacers for two-stage revision THA. Because constrained liners are typically preferred in patients at higher risk of instability, our findings suggest that their use does not necessarily increase the risk of complications. However, because of the small sample size, larger studies are needed to demonstrate whether there is superiority of liner constraint in this patient population. LEVEL OF EVIDENCE/METHODS:Level III, therapeutic study.

BACKGROUND:Optimal femoral stem alignment and femoral canal fill have been associated with improved osteointegration in patients undergoing cementless total hip arthroplasty (THA). Direct anterior approach (DAA) has become more popular among new surgeons, and the ability to achieve appropriate stem alignment and canal fill due to limited surgical exposure may pose added risks. To mitigate these concerns, several modern tissue sparing stem designs have been designed. This study aimed to compare implant canal fill and alignment between two of the leading DAA-friendly femoral stems available. METHODS:This was a multi-center, retrospective study of patients who underwent DAA THA with either A (n = 149) or B stem (n = 85) between 2021 and 2023 and had a minimum one-year follow-up. Radiographic measures of proximal femoral morphology, including canal calcar ratio (CCR), Morphological Cortical Index (MCI), and Dorr Class (based on the CCR), as well as postoperative measures including femoral canal fill ratio (CFR), signs of osteointegration and stem alignment were analyzed and compared between stem types. RESULTS:, p = 0.082). Spot weld formation was significantly higher in stem A group (59.7% vs. 37.6%, P = 0.001). CONCLUSION/CONCLUSIONS:For patients with similar femoral morphology undergoing DAA THA, the stem A group demonstrated superior anatomical fit in the metaphyseal region, as evidenced by CFR, spot weld formation and implant positioning. Further longer follow up research is needed to elucidate these findings and their correlation to clinical outcomes.

BACKGROUND:Methylene blue (MB), a phenothiazine dye with antimicrobial activity, is used to stain soft tissues and guide thoroughness of debridement during revision total knee arthroplasty (rTKA) for periprosthetic joint infection (PJI). The purpose of this study was to determine if instillation of MB prior to arthrotomy impacts culture yield in TKA PJI. METHODS:We retrospectively reviewed 266 patients diagnosed with TKA PJIs according to the 2018 International Consensus Meeting (ICM) criteria from January 2018 - March 2023 at a single academic hospital. Demographics, perioperative outcomes, and preoperative and intraoperative culture positivity were compared between patients who received intraoperative MB (MB group; n = 26) and those who did not (nMB group; n = 241). A record of detected organisms was included in the analysis. RESULTS:There was no difference in preoperative aspiration culture positivity between groups. However, the MB group had a higher percentage of preoperative to intraoperative culture concordance (89.5 vs. 69.9%; P = 0.04). Although the overall rate of intraoperative culture positivity did not differ significantly between groups, the MB group had more intraoperative cultures obtained per patient (4.9 vs. 4.5; P = 0.02) and higher numbers of positive intraoperative cultures per patient. Concordance rates for patients in both groups with positive preoperative and negative intraoperative cultures were similar (10.5 vs. 16.5%, P = 0.50). Among patients with negative preoperative cultures, intraoperative culture positivity was more discordant in the MB group (0 vs. 18.8%; P = 0.03). There was no difference in the number of patients that received antibiotics following aspiration (68.4 vs. 49.6%; P = 0.12). CONCLUSION/CONCLUSIONS:While MB use did not affect overall culture positivity, it could interfere with intraoperative pathogen detection in patients with negative preoperative cultures. In these cases, MB should be avoided to decrease inaccuracies in intraoperative culture yield. If preoperative cultures are positive, MB may improve surgical debridement and likelihood of infection eradication.

BACKGROUND:High body mass index (BMI) is a risk factor for tibial baseplate loosening following total knee arthroplasty (TKA) but may not adequately correlate with stresses at the tibial baseplate. In this study, we aimed to determine an optimal cutoff of a weight-to-tibial baseplate surface-area ratio (weight/SA) for predicting aseptic tibial baseplate loosening. We further examined whether tibial stem extensions have a protective effect. METHODS:We identified 16,368 patients who underwent primary, elective TKA from June 2011 to March 2023. Patient demographics, including age, sex, and race, implants used, and revision surgeries were extracted. Revisions were manually reviewed to confirm revision indications. The exact surface areas of tibial baseplates were obtained from manufacturers. Receiver operating characteristic (ROC) analysis of patients without tibial stem extensions was utilized to examine the utility of BMI and weight/SA for predicting aseptic tibial baseplate loosening. Optimal weight/SA and BMI cutoffs for predicting loosening were determined. The effect of tibial stem extensions on loosening was then examined in patients at or above (n = 7,698; 3.7% with stem extension) and below (n = 8,670; 1.3% with stem extension) the determined weight/SA cutoff. RESULTS:There were 16,368 patients in the final sample (median age, 67 years; 68.9% female; 54.1% White). Weight/SA (area under the curve [AUC] = 0.653; p < 0.001) was a better predictor of aseptic tibial baseplate loosening requiring revision compared with patient BMI (AUC = 0.624; p < 0.001). The optimal weight/SA cutoff for predicting loosening was 0.0162 kg/mm2 (sensitivity = 0.747, specificity = 0.537). Multivariable logistic regression demonstrated that being at or above the weight/SA cutoff (odds ratio [OR] = 3.17; p < 0.001) but not the BMI cutoff (p = 0.911) was a significant predictor of revision for tibial baseplate loosening in patients without stem extensions. No cases of revision for aseptic tibial baseplate loosening in patients with stem extensions occurred either at or above or below the cutoff. The rate of revision for aseptic tibial baseplate loosening in patients without stem extensions was 0.3% for patients below and 1.0% for patients at or above the weight/SA cutoff. CONCLUSIONS:The ratio of weight-to-tibial baseplate surface area was more predictive of revision for aseptic tibial baseplate loosening following TKA compared with BMI alone. For patients with obesity with small tibial baseplate sizes, utilization of a tibial stem extension may protect against tibial loosening. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Changing from standing to sitting positions requires rotation of the femur from an almost vertical plane to the horizontal plane. Osteoarthritis of the hip limits hip extension, resulting in less ability to recruit spinopelvic tilt (SPT) while standing and requiring increased SPT while sitting to compensate for the loss of hip range of motion. To date, the effect of total hip arthroplasty (THA) on spinopelvic sitting and standing mechanics has not been reported, particularly in the setting of patients with coexistent sagittal plane spinal deformity. METHODS:A retrospective review was performed of patients ≥18 years of age undergoing unilateral THA for hip osteoarthritis with sitting and standing radiographs made before and after THA. Alignment was analyzed at baseline and follow-up after THA in both standing and sitting positions in a relaxed posture with the fingers resting on top of the clavicles. Patients were grouped according to the presence or absence of sagittal plane deformity preoperatively into 3 groups: no sagittal plane deformity (normal), thoracolumbar (TL) deformity (pelvic incidence-lumbar lordosis [PI-LL] mismatch > 10° and/or T1-pelvic angle [TPA] > 20°), or apparent deformity (PI-LL ≤ 10° and TPA ≤ 20°, but sagittal vertical axis [SVA] > 50 mm). RESULTS:In this study, 192 patients were assessed: 64 had TL deformity, 39 had apparent deformity, and 89 had normal alignment. Overall, patients demonstrated a reduction in standing SVA (45 to 34.1 mm; p < 0.001) and an increase in SPT (14.6° to 15.7°; p = 0.03) after THA. There was a greater change in standing SVA (p < 0.001) among patients with apparent deformity (-29.0 mm) compared with patients with normal alignment (0.9 mm) and patients with TL deformity (-16.3 mm). Those with apparent deformity also experienced the greatest difference (p = 0.03) in postural SPT change (moving from standing to sitting) (-10.1°) from before to after THA when compared with those with normal alignment (-3.6°) and TL deformity (-1.2°). The difference in postural SVA change from before to after THA was also greatest (p < 0.001) in those with apparent deformity (32.1 mm) compared with those with normal alignment (6.5 mm) and TL deformity (17.3 mm). CONCLUSIONS:Postural changes in spinopelvic alignment vary after THA depending on the presence of TL deformity or apparent deformity due to hip flexion contracture. Patients with apparent deformity had larger changes in standing and sitting alignment than patients with TL deformity or patients with normal alignment. The assessment of global sagittal alignment findings can be used to predict the likelihood of improvement in sagittal alignment after THA. LEVEL OF EVIDENCE/METHODS:Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Total hip arthroplasty and total knee arthroplasty are among the most successful orthopedic procedures, with increasing numbers performed annually in the United States. However, adverse perioperative complications like acute kidney injury (AKI) can adversely affect patient outcomes and increase health care costs. The incidence of AKI post-total joint arthroplasty varies widely, with large-scale studies reporting less than 2% and smaller studies indicating rates as high as 21.9%. Holding angiotensin converting enzyme inhibitors, aldosterone receptor blockers, NSAIDs, diuretics, and avoiding nephrotoxic antibiotics can help mitigate the risk.

BACKGROUND:Inflammatory bowel disease (IBD) can have orthopaedic manifestations related to decreased bone mineral density and increased fracture risk. The impact of IBD-spectrum diseases, including Crohn's disease (CD) and ulcerative colitis (UC), on the overall performance of total hip arthroplasty (THA), is not well understood. The present study sought to evaluate whether patients who have IBD were at increased risk of THA failure compared to those who did not have IBD. METHODS:The Statewide Planning and Research Cooperative System (SPARCS) was used to compare postoperative outcomes between patients who have IBD (CD and UC) and patients who do not have IBD from 2010 to 2020. A total of 119,094 patients were included in the study, of whom 1,165 had a diagnosis of IBD. Overall, 501 of those had CD, while 664 had UC. RESULTS:When controlling for comorbidities, patients who had CD had longer hospital length of stay (CD: 3.6 +/- 2.5 versus UC: 3.4 +/- 2.1 versus control: 3.2 +/- 2.3 days, P < 0.001), higher rates of 90-day readmission (CD: 13.6 versus UC: 8.3 versus control: 7.7%, P < 0.001) and 1-year readmission (CD: 20.4 versus UC: 15.1 versus control: 12.8%, P < 0.001), and higher rates of 90-day emergency room visits (CD: 15.4 versus UC: 12 versus control: 11.1%, P = 0.007). There were no differences in all-cause revision or revision for periprosthetic joint infection (PJI) between CD and UC compared with control patients. CONCLUSIONS:Patients who have UC had more emergency room visits and hospital readmissions following THA, however, survival analysis demonstrated that IBD patients are not at increased risk of revision or PJI after THA.

BACKGROUND:Patient comorbidities can lead to worse outcomes and increase the risk of revisions after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Sparse research is available on the effects of ostomies on postoperative outcomes. Our study aimed to assess whether patients who have ostomies, who underwent TKA or THA, have worse outcomes and increased rates of all-cause and periprosthetic joint infection (PJI)-related revisions. METHODS:We performed a retrospective cohort study comparing the outcomes of THA and TKA patients who have and do not have a history of ostomy using the Statewide Planning and Research Cooperative System. Patient demographics, ostomy diagnosis, 3-month emergency department visits and readmissions, and revisions were collected. A total of 126,414 THA and 216,037 TKA cases were included. Log-rank testing and a Cox proportional hazards model were used to account for covariates. RESULTS:In total, 463 THA patients (0.4%) had ostomies. They had a longer length of stay (4.0 versus 3.1 days, P < 0.001) and were less likely to be discharged home (55.3 versus 62.2%, P = 0.01). They had higher rates of PJI-related revisions (1.9 versus 0.9%, P = 0.02) and had increased odds of PJI-related revision (OR [odds ratio] = 2.2, P = 0.02). Of TKA patients, 619 patients (0.3%) had an ostomy. They had a longer length of stay (3.6 versus 3.3 days, P = 0.02) and was less likely to be discharged home (49.4 versus 52.4%, P = 0.16). However, there was no difference in the rate (1.8 versus 1.4%, P = 0.49) or odds (OR = 1.2, P = 0.53) of PJI-related revision. CONCLUSIONS:THA, but not TKA, patients who have ostomies have an increased risk of PJI-related revisions. The proximity of the surgical incision to the ostomy site may play a role in the risk of PJI in THA patients.

PURPOSE/OBJECTIVE:This study aimed to evaluate the safety of total knee arthroplasty (TKA) in Jehovah's Witness patients compared to non-Jehovah's Witness patients using standard peri-operative TKA protocols as well as assess the role of tranexamic acid (TXA) in managing blood loss in this population. METHODS:Patients undergoing TKA between 2011 and 2021 at two tertiary academic centers were retrospectively reviewed. Patient demographics, pre- and post-operative hematologic laboratory values, intra-operative tranexamic acid use, 90-day post-operative complications, and subsequent revisions were collected. These variables were then compared between propensity score-matched cohorts at a 2:1 ratio of those who did not identify as Jehovah's Witness to those who did. Regression analysis was used to determine the effect of intraoperative TXA on hemoglobin (hgb) shift. RESULTS:After applying exclusion criteria and matching, the TKA outcomes of 316 non-Jehovah's Witness patients and 152 Jehovah's Witness patients were analyzed. Univariate analysis suggested that non-Jehovah's Witness patients and Jehovah's Witness patients had similar pre- and post-operative hgb, hgb shift, and hematocrit (hct). Only 1 (0.8%) Jehovah's Witness patient reached a hgb < 8.0 mg/dL post-operatively. Multivariate logistic regression suggested that Jehovah's Witness patients did not have increased odds of reaching a hgb < 8.0 mg/dL (odds ratio [OR] = 0.99 [0.96, 1.02]; P = 0.42). Multivariate linear regression suggested that intra-operative TXA was positively correlated with hgb shift and thus a smaller decrease in hgb from pre- to post-TKA (β = 0.38 [0.06, 0.69]; P = 0.02). Additionally, Jehovah's Witness patients had excellent revision-free (95% [91, 99]) and infection-free (98% [95, 100]) survival at 8 years. CONCLUSION/CONCLUSIONS:Standard peri-operative TKA protocols are safe for Jehovah's Witness patients who do not have the need for transfusion, especially with appropriate pre-operative hgb levels and the use of intra-operative TXA. Furthermore, these patients have excellent survivorship at 5 and 8 years follow-up.