Is Preoperative Weight Reduction in Patients Who Have Body Mass Index ≥ 40 Associated With Lower Complication Rates After Primary Total Hip Arthroplasty?

BACKGROUND: Given the heightened risk of postoperative complications associated with obesity, delaying total hip arthroplasty (THA) in patients who have a body mass index (BMI) > 40 to maximize preoperative weight loss has been advocated by professional societies and orthopaedic surgeons. While the benefits of this strategy are not well-understood, previous studies have suggested that a 5% reduction in weight or BMI may be associated with reduced complications after THA. METHODS: We identified 613 patients who underwent primary THA in a single institution during a 7-year period and who had a BMI >40 recorded from 9 to 12 months prior to surgery. Subjects were stratified into 3 cohorts based on whether their baseline BMI decreased by >5% (147 patients, 24%), was unchanged ( ± 5%) (336 patients, 55%), or increased by >5% (130 patients, 21%) on the day of surgery. The frequency of 90-days Hip Society and Centers for Medicare & Medicaid Services complications was compared between these cohorts. There were significant baseline differences between the cohorts with respect to baseline American Society of Anesthesiologists class (P < .001) and hemoglobin A1C (P = .011), which were accounted for in a multivariate regression analysis. RESULTS: In univariate analysis, there was a lower incidence of readmission (P = .025) and total complications (P = .005) in the increased BMI cohort. The overall complication rate was 18.4% in the decreased BMI cohort, 17.6% in the unchanged cohort, and 6.2% in the increased cohort. However, multivariable regression analysis controlling for potential confounders did not find that preoperative change in BMI was associated with differences in 90-days complications between cohorts (P > .05). CONCLUSIONS: Patients who have a BMI >40 and achieved a clinically significant (>5%) BMI reduction prior to THA did not have a lower risk of 90-days complications or readmissions. Thus, delaying THA in these patients to encourage weight loss may result in restricting access to a beneficial surgery without an appreciable safety benefit.

Changing the definition of treatment success alters treatment outcomes in periprosthetic joint infection: a systematic review and meta-analysis.

Background: Variability in the definition of treatment success poses difficulty when assessing the reported efficacy of treatments for hip and knee periprosthetic joint infection (PJI). To address this problem, we determined how definitions of PJI treatment success have changed over time and how this has affected published rates of success after one-stage and two-stage treatments for hip and knee PJI. Methods: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted to identify one-stage and two-stage revision hip and knee PJI publications in major databases (2006-2021). Definition of treatment success, based on Musculoskeletal Infection Society tier criteria, was identified for each study. Publication year, number of patients, minimum follow-up, and study quality were also recorded. The association of success definitions and treatment success rate was measured using multi-variable meta-regression. Results: Study quality remained unchanged in the 245 publications included. Over time, no antibiotics (tier 1) and no further surgery (tier 3) (40.7 % and 54.5 %, respectively) became the two dominant criteria. After controlling for type of surgery, study quality, study design, follow-up, and year of publication, studies with less strict success definitions (tier 3) reported slightly higher odds ratios of 1.05 [1.01, 1.10] ( p = 0.009 ) in terms of treatment success rates compared to tier 1. Conclusions: PJI researchers have gravitated towards tier-1 and tier-3 definitions of treatment success. While studies with stricter definitions had lower PJI treatment success, the clinical significance of this is unclear. Study quality, reflected in the methodological index for non-randomized studies (MINORS) score, did not improve. We advocate for improving PJI study quality, including clarification of the definition of treatment success.

Characterizing the Magnitude and Risk Factors of Functional and Anatomic Limb Lengthening in Patients Undergoing Revision Total Knee Arthroplasty.

BACKGROUND: In revision total knee arthroplasty (TKA), there is little information on the magnitude of potential limb lengthening, risk factors for lengthening, or its impact on patient-reported outcome measures. We aimed to quantify limb length alteration during revision TKA and assess risk factors for lengthening. METHODS: We identified 150 patients over a 3-year period who underwent revision TKA and had preoperative and postoperative EOS hip-to-ankle standing radiographs. The average patient age was 64 years, 51% were women; 68% had a preoperative varus deformity and 21% had a preoperative valgus deformity. Outcomes assessed included change in functional and anatomic limb length, risk factors for lengthening, and clinical outcome scores, including the Knee Osteoarthritis Outcome Score Joint Replacement, and the Veterans RAND 12-item Physical and Mental Scores. RESULTS: There were 124 patients (83%) who had functional limb lengthening, and 108 patients (72%) had anatomic limb lengthening. Patients had an average functional limb lengthening of 7 mm (range, -22 to 35) and an average anatomic limb lengthening of 5 mm (range, -16 to 31). Patients undergoing revision for instability experienced significantly greater anatomic lengthening (7.6 versus 4.6, P = .047). Patients who had ≥ 10° of deformity were more likely to be functionally lengthened (91 versus 79%) and had significantly greater average functional lengthening (12 versus 6 mm; P = .003). There was no significant change in clinical outcome scores at 6 weeks and 1 year for patients lengthened ≥ 5 or 10 mm compared to those not lengthened as substantially. CONCLUSIONS: There is major potential for functional and anatomic limb lengthening following revision TKA, with greater preoperative deformity and revision for instability being risk factors for lengthening.

Should We Wait for Bone-on-Bone Arthritis? Equivalent Clinical Outcomes in Patients Requiring Advanced Imaging Before Primary Total Hip Arthroplasty.

BACKGROUND: Plain radiographs remain the standard for diagnosing osteoarthritis (OA). Total hip arthroplasty (THA) is generally offered only for advanced OA by plain radiographs. Advanced imaging is used as an adjunct to assess OA severity in cases of progressive symptoms with less advanced OA by plain radiographs. The objective of this study was to compare outcomes following THA in patients who have advanced OA visualized by plain radiographs to patients who have less severe OA visualized by plain radiographs. METHODS: From February 2016 to February 2020, 93 patients who had Kellgren-Lawrence (KL) grade 0 to 2 OA and underwent THA were identified. The median age was 65 years, and 55% were women. They were matched 1:3 to patients who underwent THA for KL 4 OA based on age, sex, body mass index, and Charlson Comorbidity Index. The primary outcome was achievement of the Hip Injury and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) minimum clinically important difference, substantial clinical benefit, and patient-acceptable symptom state at 1 year postoperatively. RESULTS: There was no difference between the KL 0 to 2 and KL 4 cohorts in the achievement of HOOS JR minimum clinically important difference (86 versus 85.6%, P = .922), substantial clinical benefit (81.7 versus 80.2%, P = .751), or patient-acceptable symptom state (89.2 versus 85.6%, P = .374). The KL 0 to 2 cohort had a similar improvement in their 2-year HOOS JR (42.5 versus 38.6, P = .019). CONCLUSIONS: In this series, there was no difference in outcomes following primary THA between patients who have severe OA on plain radiographs (KL 4) compared to those who have less severe OA (KL 0 to 2). In the setting of severe symptoms and the absence of advanced OA on radiographs, advanced imaging can be used to guide treatment and select patients who could benefit from THA.

Do one-stage indications predict success following two-stage arthroplasty for chronic periprosthetic joint infection?

Introduction: The 2018 International Consensus Meeting (ICM) proposed criteria for one-stage exchange arthroplasty in treating periprosthetic joint infection (PJI). Our study aimed to determine what proportion of PJI patients met the 2018 ICM criteria and how this affected infection-free survivorship for patients. Methods: All chronic PJI patients treated with two-stage exchange within our institution between 2017-2020 were retrospectively reviewed. Included cases met 2011 Musculoskeletal Infection Society (MSIS) criteria for PJI and had a 2-year minimum follow-up. Treatment success was defined as Tier 1A in the 2019 MSIS working group definition. ICM one-stage criteria included non-immunocompromised host, absence of sepsis, adequate soft tissue for closure, known preoperative pathogen, and susceptibility. Immunocompromised host was analyzed as two separate definitions. Kaplan-Meier survivorship, Cox regression, and univariate analyses were performed. Results: A total of 293 chronic PJI patients were included. Overall, treatment failure occurred in 64/293 (21.8 %) patients. Only 13 % (n=37) met ICM criteria definition no. 1 for one-stage exchange; 12 % (n=33) met definition no. 2. In both definitions, infection-free survivorship at 2 years did not differ between patients who met and did not meet criteria (p>0.05). Cox proportional hazard regression analyses demonstrated that the only variable predicting treatment failure was knee joint involvement (p=0.01). Conclusions: We found that a very limited number of chronic PJI patients were suitable for a one-stage exchange. Furthermore, the supposition that healthier hosts with known pathogens (the basis of the ICM criteria) yield better PJI treatment outcomes was not observed. These results justify the ongoing multicenter randomized control trial comparing one-stage versus two-stage treatment for chronic PJI.

Clinical Outcomes of Isolated Polyethylene Exchange Versus Full Component Revision for the Management of Instability Following Total Knee Arthroplasty.

BACKGROUND: Instability following total knee arthroplasty (TKA) is a common cause for revision. Isolated polyethylene exchange (IPE) can be performed to increase knee joint stability, but results have been mixed. The purpose of this study was to compare the survivorship and patient-reported outcomes of patients undergoing revision TKA for instability with IPE versus full component revision. METHODS: We reviewed 280 primary TKAs undergoing revision TKA for instability. There were 181 knees that underwent revision with IPE, compared to 99 knees treated with full component revision. The mean follow-up was 32.8 months (range, 24.8 to 82.5). Patient demographics, radiographic parameters, prosthesis constraints, reoperations for instability, and patient-reported outcomes were compared. RESULTS: The survivorship for instability was significantly higher at 2 years (99 versus 92%, P = .024) and 5 years (94 versus 84%, P = .024) for patients undergoing full component revision. Although there was no difference in Knee Injury and Osteoarthritis Outcome Score for Joint Replacements and Veterans RAND 12 physical component scores between the 2 groups at 6 weeks, 1 year, and 2 years after surgery, full revision patients reported greater pain relief (P = .006) and greater improvements in Veterans RAND 12 physical component scores (P = .027) at 1 year and Knee Injury and Osteoarthritis Outcome Score for Joint Replacements scores at 2 years (P = .017) compared to IPE patients. Men were associated with an increased risk for recurrent instability following IPE (hazard ratio 3.3, 95% confidence interval: [1.0 to 10.6]). CONCLUSIONS: Isolated polyethylene exchange was not as reliable or durable compared to full component revision for the management of postoperative instability. These procedures should only be reserved in cases with competent collaterals and when component position, offset, and rotation are optimized.

Substantial Weight Loss May Not Improve Early Outcomes of Total Knee Arthroplasty in the Morbidly Obese.

BACKGROUND: Body mass index (BMI) cutoffs for morbidly obese patients otherwise indicated for total knee arthroplasty (TKA) have been widely proposed and implemented, though they remain controversial. Previous studies suggested that a 5% reduction in BMI may be associated with fewer postoperative complications. Thus, the purpose of this study was to determine whether a substantial reduction in preoperative BMI in morbidly obese patients improved 90-day outcomes after TKA. METHODS: There were 1,270 patients who underwent primary TKA at a single institution and had a BMI > 40 recorded during the year prior to surgery. Patients were stratified into three cohorts based on whether their BMI within 3 months to 1 year preoperatively had decreased by ≥ 5% (228 patients [18%]); increased by ≥ 5% (310 [24%]); or remained unchanged (within 5%) (732 [58%]) on the day of surgery. There were several baseline differences between the cohorts with respect to medical comorbidities. The rate of 90-day complications and six-week patient-reported outcome measures were compared via univariate and multivariable analyses. RESULTS: On univariate analysis, individual and total complication rates were similar between the cohorts (P > .05). On multivariable logistic regression, the risk of complications was similar in patients who had decreased versus unchanged BMI (OR [odds ratio] 1.0; P = .898). However, there was a higher risk of complications in the increased BMI cohort compared to those patients who had an unchanged BMI (OR 1.5; P = .039). The six-week patient-reported outcome measures were similar between the cohorts. CONCLUSIONS: Patients who have a BMI > 40 who achieved a meaningful reduction in BMI prior to TKA did not have a lower rate of 90-day complications than those whose BMI remained unchanged. Furthermore, considering that nearly one in four patients experienced a significant increase in BMI while awaiting surgery, postponing TKA may actually be detrimental.

Perioperative Cefazolin for Total Joint Arthroplasty Patients Who Have a Penicillin Allergy: Is It Safe?

BACKGROUND: Cefazolin is the standard of care for perioperative antibiotic prophylaxis in total joint arthroplasty (TJA) in the United States. The potential allergic cross-reactivity between cefazolin and penicillin causes uncertainty regarding optimal antibiotic choice in patients who have a reported penicillin allergy (rPCNA). The purpose of this study was to determine the safety of perioperative cefazolin in PCNA patients undergoing primary TJA. METHODS: We identified all patients (n = 49,842) undergoing primary total hip arthroplasty (n = 25,659) or total knee arthroplasty (n = 24,183) from 2016 to 2022 who received perioperative intravenous antibiotic prophylaxis. Patients who had an rPCNA (n = 5,508) who received cefazolin (n = 4,938, 89.7%) were compared to rPCNA patients who did not (n = 570, 10.3%), and to patients who did not have an rPCNA (n = 43,359). The primary outcome was the rate of allergic reactions within 72 hours postoperatively. Secondary outcomes included the rates of superficial infections, deep infections, and Clostridioides difficile infections within 90 days. RESULTS: The rate of allergic reactions was 0.1% (n = 5) in rPCNA patients who received cefazolin, compared to 0.2% (n = 1) in rPCNA patients who did not (P = .48) and 0.02% (n = 11) in patients who have no rPCNA (P = .02). Allergic reactions were mild in all 5 rPCNA patients who received cefazolin and were characterized by cutaneous symptoms (n = 4) or dyspnea in the absence of respiratory distress (n = 1) that resolved promptly with antibiotic discontinuation and administration of antihistamines and/or corticosteroids. We observed no differences in the rates of superficial infections (0.1 versus 0.2%, P = .58), deep infections (0.3 versus 0.4%, P = .68), or C difficile infections (0.04% versus 0%, P = .99) within 90 days in rPCNA patients who received cefazolin versus alternative perioperative antibiotics. CONCLUSIONS: In this series of more than 5,500 patients who had an rPCNA undergoing primary TJA, perioperative prophylaxis with cefazolin resulted in a 0.1% incidence of allergic reactions that were clinically indolent. Cefazolin can be safely administered to most patients, independent of rPCNA severity. LEVEL OF EVIDENCE: III.

Femoral Component Debonding Frequently Missed on Advanced Imaging Prior to Revision of a Recalled Total Knee Arthroplasty.

BACKGROUND: Identification of femoral component debonding in the work-up of painful total knee arthroplasty (TKA) often poses a diagnostic challenge. The purpose of this study was to compare the sensitivity and specificity of radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) for identifying femoral component loosening with debonding at the time of revision of a primary TKA with a recalled polyethylene insert. METHODS: Using an institutional database, we identified all cases of revision TKA performed for this specific implant recall following a primary TKA between 2014 and 2022. Patients who had a preoperative radiograph, CT, and MRI were included (n = 77). Sensitivity, specificity, and positive and negative likelihood ratio (LR) for predicting loosening were compared among the imaging modalities, using the intraoperative evidence of implant loosening as the gold standard. RESULTS: At the time of revision surgery, the femoral component was noted to have aseptic loosening with debonding in 46 of the 77 (60%) of the TKAs. There were no significant differences in demographics in the cohort with femoral debonding compared to those with well-fixed implants. The CT demonstrated a sensitivity of 28% and a specificity of 97%, while the MRI demonstrated a sensitivity of 37% and a specificity of 94% for detecting femoral loosening due to debonding. Both CT and MRI demonstrated poor negative LRs for femoral loosening (LR 0.7). CONCLUSIONS: In this series of revision TKAs for a specific recalled component, neither CT nor MRI accurately diagnosed femoral component debonding. For patients who have this implant, it is imperative to interrogate the implant-cement interface intraoperatively and prepare for full revision surgery as well as marked bone loss secondary to osteolysis.

Body morphometry did not affect the accuracy of a second-generation, miniature imageless navigation system for total hip arthroplasty (THA) using a posterior approach.

Introduction: Some modern imageless navigation platforms for total hip arthroplasty (THA) rely on virtual frontal and sagittal planes determined with the patient in the lateral decubitus position. Body morphometry that changes with gender, body mass index, and other demographic factors may affect accuracy in patient positioning and consequently, navigation accuracy. The objective of this study was to analyze the influence of patient factors on the intraoperative accuracy of a second-generation imageless computer-assisted surgery platform. Methods: 325 consecutive patients undergoing posterior approach, navigated THA arthroplasty for primary osteoarthritis by a single surgeon were retrospectively reviewed. An optic-based imageless navigation system referenced off a generic sagittal and coronal plane was used to determine acetabular inclination and anteversion. Acetabular accuracy was determined by assessing differences between intraoperative values and those obtained from measuring standardized 6-week follow-up radiographs. The effect of age, gender, BMI, race, ethnicity, and laterality on acetabular accuracy was assessed via t-tests, Pearson correlation and ANOVA. Results: Gender had a significant impact on raw inclination accuracy (females and males had an average error of 1.41° and -1.03°, respectively - p < 0.001). There was a weak correlation between acetabular accuracy and patient age and BMI as a continuous variable (both absolute γ < 0.2). No difference was found between acetabular accuracy and BMI groups. Conclusion: This second-generation imageless computer assisted device provided accurate cup positioning regardless of patient's BMI. Gender was the only factor impacting inclination accuracy.

Contemporary Isolated Bearing Exchange for the Management of Hip Instability Following Primary Total Hip Arthroplasty.

BACKGROUND: Isolated ball and liner exchanges (IBLEs) can be performed to increase hip joint stability, but historical results have been mixed due to a lack of head size options or dual mobility articulations. The purpose of this study was to evaluate the contemporary results of IBLEs in patients who have instability following primary total hip arthroplasty (THA). METHODS: We retrospectively reviewed 65 primary THAs from 2016 to 2020 with hip instability undergoing IBLE or conversion to dual mobility articulation. There were 31 men and 34 women who had an average age of 70 years (range, 26 to 92). The mean time to revision from primary was 40.1 months (range, 1 to 120). In 52 cases, IBLE was performed using conventional bearings, while 13 hips were converted to dual mobility. Radiographic factors, including acetabular component orientation, reproduction of hip joint offset, leg lengths, and outcomes such as recurrent instability requiring subsequent revision and patient-reported outcome measure, were recorded and compared. RESULTS: There were 12 (18.4%) hips that experienced subsequent instability and required another revision (17.3% ball and liner exchange versus 23.1% dual mobility articulation, P = .615). The mean time to rerevision for instability was 17.1 months. There were no significant differences in either acetabular component anteversion (P = .25) or restoration of hip joint offset (P = .87) in patients who required another revision for instability compared to those who did not, respectively. At 1 year, patients undergoing conventional bearing exchange reported higher Hip Dysfunction Osteoarthritis Outcome Score for Joint Replacements (P = .002) and Veterans Rand physical component (P = .023) scores compared to those who underwent a conversion to dual mobility articulation. Only age > 75 years at the time of surgery was associated with increased risk for dislocation (odds ratio 7.2, confidence interval 1.2 to 43.7, P = .032). CONCLUSIONS: Isolated bearing exchanges for instability following THA remained at high risk for subsequent instability. Conversion to dual mobility articulations did not reduce the risk of reoperation.

Obesity Severity Does Not Associate With Rate, Timing, or Invasiveness of Early Reinterventions After Total Knee Arthroplasty.

BACKGROUND: The use of body mass index (BMI) cutoff values has been suggested for proceeding with total knee arthroplasty (TKA) in obese patients. However, the relationship between obesity severity and early reoperations after TKA is poorly defined. This study evaluated whether increased World Health Organization (WHO) obesity class was associated with risk, severity, and timing of reintervention within one year after TKA. METHODS: There were 8,674 patients from our institution who had a BMI ≥ 30 and underwent unilateral TKA for primary osteoarthritis between 2016 and 2021. Patients were grouped by WHO obesity class: 4,456 class I (51.5%), 2,527 class II (29.2%), and 1,677 class III (19.4%). A chart review was performed to determine patient characteristics and identify patients who underwent any closed or open reintervention requiring anesthesia within the first postoperative year. Regression analyses were performed to identify variables associated with increased odds ratios (ORs) for requiring a reintervention, its timing, and invasiveness. RESULTS: There were 158 patients (1.8%) who required at least one reintervention, and 15 patients (0.2%) required at least 2 reinterventions. Reintervention rates for obesity classes I, II, and III were 1.8% (n = 81), 2.0% (n = 51), and 1.4% (n = 23), respectively. There were 65 closed procedures (41.1%), 47 minor procedures (29.7%), 34 open with or without liner exchange (21.5%), and 12 revisions with component exchange (7.6%). Obesity class was not associated with reintervention rate (P = .3), timing (P = .36), or invasiveness (P = .93). Diabetes (odds ratio [OR] = 2.47; P = .008) was associated with a need for reintervention. Non-Caucasian race (OR = 1.7; P = .01) and Charlson comorbidity index (OR = 2.1; P = .008) were associated with earlier reintervention. No factors were associated with the invasiveness of reintervention. CONCLUSIONS: The WHO obesity class did not associate with rate, timing, or invasiveness of reintervention after TKA in obese patients. These findings suggest that policies that restrict the indication for elective TKA based only on a BMI limit have limited efficacy in reducing early reintervention after TKA in obese patients. LEVEL OF EVIDENCE: III.

Robotics and Navigation Do Not Affect the Risk of Periprosthetic Joint Infection Following Primary Total Hip Arthroplasty: A Propensity Score-Matched Cohort Analysis.

BACKGROUND: The use of computer navigation or robotic assistance during primary total hip arthroplasty (THA) has yielded numerous benefits due to more accurate component positioning. The utilization of these tools is generally associated with longer operative times and also necessitates additional surgical equipment and personnel in the operating room. Thus, the aim of this study was to evaluate the impact of technology assistance on periprosthetic joint infection (PJI) after primary THA. METHODS: We retrospectively reviewed the records for 12,726 patients who had undergone primary THA at a single high-volume institution between 2018 and 2021. Patients were stratified by surgical technique (conventional THA, computer-navigated THA [CN-THA], or robotic-assisted THA [RA-THA]) and were matched 1:1 with use of propensity score matching. Univariate and logistic regression analyses were performed to compare the rates of PJI within 90 days postoperatively between the cohorts. RESULTS: After propensity score matching, there were 4,006 patients in the THA versus RA-THA analysis (2,003 in each group) and 5,288 patients in the THA versus CN-THA analysis (2,644 in each group). CN-THA (p < 0.001) and RA-THA (p < 0.001) were associated with longer operative times compared with conventional THA by 3 and 11 minutes, respectively. The rates of PJI after conventional THA (0.2% to 0.4%) were similar to those after CN-THA (0.4%) and RA-THA (0.4%). On the basis of logistic regression, the development of PJI was not associated with the use of computer navigation (odds ratio [OR], 1.8 [95% confidence interval (CI), 0.7 to 5.3]; p = 0.232) or robotic assistance (OR, 0.9 [95% CI, 0.3 to 2.3]; p = 0.808). CONCLUSIONS: Despite longer operative times associated with the use of computer navigation and robotic assistance, the use of these tools was not associated with an increased risk of PJI within 90 days after surgery. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Defining the Learning Period of a Novel Imageless Navigation System for Posterior Approach Total Hip Arthroplasty: Analysis of Surgical Time and Accuracy.

Introduction: The use of imageless navigation in total hip arthroplasty (THA) is frequently associated with prolonged surgical times, predominantly during the learning period. The purpose of the present study was to characterize the learning period of a novel imageless navigation system, specifically as it related to surgical time and acetabular navigation accuracy. Materials and Methods: This was a retrospective observational study of a consecutive group of 158 patients who underwent primary unilateral THA for osteoarthritis by a team headed by a single surgeon. All procedures used an imageless navigation system to measure acetabular cup inclination and anteversion angles, referencing a generic sagittal and frontal plane. Navigation accuracy was determined by assessing differences between intraoperative inclination and anteversion values and those obtained from standardized 6-week follow-up radiographs. Operative time and navigation accuracy were assessed by plotting moving averages of 7 consecutive cases. The learning period was defined using Mann-Kendall trend analyses, student t-tests and nonlinear regression modeling based on surgical time and navigation accuracy. Alpha error was 0.05. Results: The average surgical time was 67.3 min (SD:9.2) (range 45-95). The average navigation accuracy for inclination was 0.01° (SD:4.2) (range - 10 to 10), and that for anteversion was - 4.9° (SD:3.8) (range - 14 to 5). Average surgical time and navigation accuracy were similar between the first and final cases in the series with no learning period detected. Conclusions: There was no discernible learning period effect on surgical time or system measurement accuracy during the early phases of adoption for this imageless navigation system.

To Stage or Not to Stage? Comparison of Patient-Reported Outcomes, Complications, and Discharge Disposition After Staged and Simultaneous Bilateral Posterior Total Hip Arthroplasty.

BACKGROUND: Patients who have bilateral hip arthritis can be treated with bilateral total hip arthroplasty (bTHA) in either a staged or simultaneous fashion. The goal of this study was to determine whether staged and simultaneous posterior bTHA patients differ in regard to (1) patient-reported outcome measures, (2) 90-day complication rates, and (3) discharge dispositions and cumulative lengths of stay. METHODS: Patients who (1) underwent simultaneous bTHA or staged bTHA (within 12 months) using the posterior approach, and (2) completed preoperative and 1-year postoperative Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement surveys were included in the study. A total of 266 patients (87 simultaneous bTHA and 179 staged bTHA) were included. Chart review was performed to collect patient-level variables, postoperative complications, discharge dispositions, and lengths of stay. RESULTS: Staged bTHA patients had higher Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, and Veterans RAND 12-Item Health Survey physical component scores compared to simultaneous bTHA patients at 6 weeks after surgery (P = .019, .006, and .008, respectively), but these differences did not meet the minimal clinically important difference threshold for any questionnaire. Simultaneous bTHA was associated with higher rate of periprosthetic fractures (P = .034) and discharge to a location other than home (P < .001). CONCLUSIONS: There were statistically significant, but likely not clinically meaningful differences in patient-reported outcomes for staged and simultaneous bTHA patients at 6 weeks after surgery. Surgeons should be aware of the higher periprosthetic fracture risk and greater likelihood of discharge to a rehabilitation facility associated with simultaneous bTHA. Further research should aim to understand which patients may benefit most from simultaneous bTHA.

The John N. Insall Award: Does Melatonin Improve Subjective Sleep Quality After Total Knee Arthroplasty? A Randomized, Placebo-Controlled Trial.

BACKGROUND: Sleep disturbance is a common problem following total knee arthroplasty (TKA). The objective of this study was to determine if exogenous melatonin improves sleep quality following primary TKA. METHODS: A randomized, double-blind, placebo-controlled trial was conducted. A total of 172 patients undergoing unilateral TKA for primary knee osteoarthritis were randomized to receive either 5 mg melatonin (n = 86) or 125 mg vitamin C placebo (n = 86) nightly for 6 weeks. The primary outcome was the Pittsburgh Sleep Quality Index (PSQI) at 6 weeks and 90 days postoperatively. Secondary outcomes included 6-week and 90-day patient-reported outcome measures (PROMs), morphine milligram equivalents prescribed, medication compliance, adverse events, and 90-day readmissions. RESULTS: Mean PSQI scores worsened at 6 weeks before returning to the preoperative baseline at 90 days in both groups. There were no differences in PSQI scores between melatonin and placebo groups at 6 weeks (10.2 ± 4.2 versus 10.5 ± 4.4, P = .66) or 90 days (8.1 ± 4.1 versus 7.5 ± 4.0, P = .43). Melatonin did not improve the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Lower Extremity Activity Scale, Visual Analog Scale for pain, or Veterans Rand 12 Physical Component Score or Mental Component Score at 6 weeks or 90 days. Poor sleep quality was associated with worse PROMs at 6 weeks and 90 days on univariate and multivariable analyses, but melatonin did not modify these associations. There were no differences in morphine milligram equivalents prescribed, medication compliances, adverse events, or 90-day readmissions between both groups. CONCLUSIONS: Exogenous melatonin did not improve subjective sleep quality or PROMs at 6 weeks or 90 days following TKA. Poor sleep quality was associated with worse patient-reported function and pain. Our results do not support the routine use of melatonin after TKA.

The Surgical Approach Impacts Component Selection in Total Hip Arthroplasty: A Matched Cohort Study of 7,460 Hips.

BACKGROUND: A higher risk of dislocation following total hip arthroplasty (THA) has been reported for the posterior approach (PA) compared to the anterior approach (AA). Dual mobility implants, larger head sizes, and elevated or face-changing liners can reduce the risk for dislocation. It remains unclear whether the component selection is influenced by the surgical approach. METHODS: This is a retrospective study of 7,048 patients who underwent 7,460 primary THA with either AA or PA for primary hip osteoarthritis or osteonecrosis of the femoral head between 2019 and 2021. A propensity score model based on age, body mass index, height, and American Association of Anesthesiologists Score was applied. There were 2,502 AA-THA matched with 4,958 PA-THA (2,456 1:2, and 46 1:1). Groups were compared with multiple linear regression analyses/multivariate logistic regressions after controlling for American Association of Anesthesiologists Score and body mass index. In a second step, only hips operated by surgeons using both approaches were matched 1:1 (1,204 PA and AA, respectively). The same statistics were performed after controlling for "surgeon". RESULTS: The PA was associated with a more frequent use of dual mobility implants, elevated liners, face-changing liners, as well as heads with 36 mm or larger diameters, and the implanted cups were significantly larger (P < .001, respectively). These findings were consistent for both matched cohorts. CONCLUSION: The surgical approach impacts the component selection in THA. Patients undergoing PA-THA are more likely to receive implants with larger head size or stabilizing features compared to AA-THA.

Does Computer Navigation or Robotic Assistance Affect the Risk of Periprosthetic Joint Infection in Primary Total Knee Arthroplasty? A Propensity Score-Matched Cohort Analysis.

BACKGROUND: The use of technology during total knee arthroplasty (TKA) has been associated with more accurate component position and less blood loss. Yet to date, the risk of developing prosthetic joint infection (PJI) associated with computer navigation (CN) or robotic assistance (RA) has not been thoroughly evaluated. This study used propensity score-matching (PSM) in a large cohort of primary TKA patients to compare the rate of PJI following conventional TKA (TKA) versus CN-TKA and RA-TKA. METHODS: We retrospectively reviewed 13,015 knees in 11,727 patients who underwent primary TKA at a single institution from 2018 to 2021. The cohort was stratified into TKA, CN-TKA, and RA-TKA groups. 1:1 PSM was applied to 11,834 patients. Propensity score-matching was performed using logistic regression accounting for age, sex, body mass index, Charlson Comorbidity Index (CCI) score, CCI components, and smoking status. Univariate and multivariable analyses were performed to evaluate differences in surgical time and PJI rate. RESULTS: Significantly longer median operating times were noted in the RA-TKA group (14 minutes) compared to TKA (P < .001). The PJI rates among matched cohorts were similar among RA-TKA (0.3%), CN-TKA (0.3%), and conventional TKA (0.5%). Multivariable logistic regressions demonstrated that the use of robotic assistance (odds ratio (OR) = 0.5, P = .423) or computer navigation (OR = 0.61, P = .128) was not associated with increased risk of PJI when compared to conventional TKA. CONCLUSIONS: Use of computer navigation and robotic assistance during primary TKA are associated with longer surgical times, but no difference in PJI frequency within 90 days of surgery.

Clinical and Biomechanical Evaluation of Mid-Level Constrained and Posterior-Stabilized Polyethylene Inserts in Primary Total Knee Arthroplasty: An Analysis of 12,674 Cases.

BACKGROUND: Mid-level constraint polyethylene designs provide additional stability in total knee arthroplasty (TKA). The purposes of this study were to (1) compare the survivorship and reason for revision between mid-level inserts and posterior-stabilized (PS) used in primary TKA and (2) evaluate the biomechanical constraint characteristics of mid-level inserts. METHODS: We reviewed all cases of primary TKA performed at our institution from 2016 to 2019 using either PS or mid-level constrained inserts from 1 of 6 manufacturers. Data elements included patient demographics, implants, reasons for revision, and whether a manipulation under anesthesia was performed. We performed finite element analyses to quantify the varus/valgus and axial-rotation constraint of each mid-level constrained insert. A one-to-one propensity score matching was conducted between the patients with mid-level and PS inserts to match for variables, which yielded 2 cohorts of 3,479 patients. RESULTS: For 9,163 PS and 3,511 mid-level TKAs, survivorship free from all-cause revision was estimated up to 5 years and was lower for mid-level than PS inserts (92.7 versus 94.1%, respectively, P = .004). When comparing each company's mid-level insert to the same manufacturer's PS insert, we found no differences in all-cause revision rates (P ≥ .91) or revisions for mechanical problems (P ≥ .97). Using propensity score matching between mid-level and PS groups, no significant differences were found in rates of manipulation under anesthesia (P = .72), all-cause revision (P = .12), revision for aseptic loosening (P = .07), and revision for instability (P = .45). Finite element modeling demonstrated a range in varus/valgus constraint from ±1.1 to >5°, and a range in axial-rotation constraint from ±1.5 to ±11.5° among mid-level inserts. CONCLUSIONS: Despite wide biomechanical variations in varus/valgus and axial-rotation constraint, we found minimal differences in early survivorship rates between PS and mid-level constrained knees.

Activity Following Total Hip Arthroplasty: Which Patients Are Active, and Is Being Active Safe?

BACKGROUND: Younger and physically active patients demand a return to sport after total hip arthroplasty (THA). However, because of the risk of implant wear and loosening, high-impact activities are often not recommended. The current study evaluates predictive factors and revision rates in patients with higher activity levels. METHODS: This retrospective study included 4152 hips in 3828 patients aged 45-75 that underwent primary THA for primary osteoarthritis between 2009 and 2019 with a minimum follow-up of 2 years. Pain and Lower Extremity Activity Scale (LEAS) were assessed before and 2 years after surgery. Activity was classified as low (LEAS 1-6), moderate (LEAS 7-13), or high (LEAS 14-18). RESULTS: Pain and LEAS improved from preoperative to 2-years postoperative (p < 0.001). The activity level was low in 6.2%, moderate in 52.9%, and high in 40.9% of the patients. Younger age, lower BMI, ASA, and CCI, male sex, and higher preoperative LEAS correlated with higher activity at 2 years (p < 0.001). The predicted revision-free survival rates between the activity groups were better for more highly active patients (p < 0.001). CONCLUSIONS: High physical activity 2 years following THA, with participating in sports like jogging several times a week, did not increase the risk of revision surgery. THA patients should not be prevented from a highly active lifestyle.