A Comparison of Clinical Outcomes after Total Knee Arthroplasty in Patients Who Have and Do Not Have Self-Reported Nickel Allergy: Matched and Unmatched Cohort Comparisons.

INTRODUCTION: The impact of a preoperative self-reported nickel allergy in patients undergoing primary total knee arthroplasty (TKA) remains unclear. The aim of this study was to compare the revision rates and outcomes of patients who have a self-reported nickel allergy undergoing primary TKA to patients who do not have a self-reported nickel allergy. METHODS: Over 5 years, a total of 284 TKAs in patients who have and 17,735 in patients who do not have a self-reported nickel allergy were performed. Revision rates and differences in preoperative and postoperative patient-reported outcome measures (PROMs), including Knee Osteoarthritis Outcome Score Joint Replacement (KOOS JR), Visual Analog Scale (VAS), Lower Extremity Activity Scale (LEAS), and the Patient-Reported Outcomes Measurement Information System (PROMIS) Mental and Physical Scores, were compared. RESULTS: Survivorship free of all-cause revision at 1 year was similar for patients who have and do not have a self-reported nickel allergy (99.5% [95% CI (confidence interval): 98.6 to 100.0] versus 99.3% [95% CI: 99.1 to 99.4]), P = 0.49). Patients who have a self-reported nickel allergy undergoing primary TKA had no difference in KOOS JR, VAS, or LEAS scores at 6 weeks and 1 year, and slightly worse PROMIS mental and physical scores at 6 weeks compared to patients who did not have an allergy. Matched analysis revealed no difference in 6-week or 1-year KOOS, JR scores between patients who did and did not have a self-reported nickel allergy when stratified by implant class (nickel-free versus standard Cobalt Chromium (CoCr)) (P = 0.113 and P = 0.415, respectively). CONCLUSIONS: Patients who have a self-reported nickel allergy can be advised that, on average, their clinical outcome scores will improve similarly to patients who do not have a self-reported nickel allergy, and revision rates will be similar.

Implant Choice May Reduce the Risk of Early Mechanical Failure in Total Ankle Replacement.

BACKGROUND: Total ankle replacements (TARs) have rapidly advanced in terms of volume, technique, design, and indications. However, TARs are still at risk for early mechanical failure and revision. Prior studies have investigated potential risk factors for failure, but have been limited to smaller series or older implants. This study sought to identify risk factors for early mechanical failure in modern TAR. METHODS: This is a retrospective study of a single-institution registry. Five surgeons contributed cases involving patients who underwent a primary TAR with any implant. Implants were grouped on the basis of the type of fixation. The primary outcome was early mechanical failure (revision with component removal for a non-infectious etiology, that is, subsidence, aseptic loosening, and/or malalignment). Logistic regression determined the effects of age, weight, hindfoot arthrodesis, implant type, and radiographic deformity on failure. RESULTS: The 731 included patients had a mean follow-up of 2.7 years. Ten percent (71 patients) had hindfoot arthrodesis. There were 33 mechanical failures (4.5%) at a mean of 1.7 years after the index surgical procedure. Our model demonstrated that hindfoot arthrodesis was associated with 2.7 times greater odds of failure (p = 0.045), every 10 kg of body weight increased the odds of tibial-sided failure by 1.29 times (p = 0.039), and implants with more extensive tibial fixation (stems or keels) lowered the odds of tibial failure by 95% (p = 0.031). CONCLUSIONS: In patients with uncontrollable risk factors (hindfoot arthrodesis) or risk factors that may or may not be modifiable by the patient (weight), implants with more robust tibial fixation may be able to reduce the risk of early mechanical failure. Further research is warranted to support efforts to decrease early failure in TAR. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach.

BACKGROUND: There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, reoperation, revision, and patient-reported outcome measures between patients undergoing DAA and PLA robotic-assisted primary THA. METHODS: We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, using DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, reoperation, and revision. Achievement of patient acceptable symptom state and minimum clinically important difference were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR) and Visual Analog Scale. RESULTS: Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = .210). There was no difference in 2-year reoperation-free survivorship (97.8 versus 98.6%, P = .59) or revision-free survivorship (98.8 versus 99.0%, P = .87) at any time point. After controlling for age, sex, and body mass index, there was no difference in dislocation, reoperation, or revision. At 6-week follow-up, after controlling for age, sex, and body mass index, patients in the DAA cohort had higher odds of achieving HOOS JR minimum clinically important difference (odds ratio = 2.01, P = .012) and HOOS JR patient acceptable symptom state (odds ratio = 1.72, P = .028). There were no differences in patient-reported outcome measures by 3 months. CONCLUSIONS: For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, reoperation, or revision rates.

A Patient-Reported Outcome-Based Comparison of Cheilectomy With and Without Proximal Phalangeal Dorsiflexion Osteotomy for Hallux Rigidus.

INTRODUCTION: This study provides the first comparison of patient-reported outcomes between isolated cheilectomy (C) and cheilectomy with Moberg (CM) osteotomy for hallux rigidus. METHODS: A single-center, retrospective registry search identified all patients with preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores who underwent cheilectomy, with and without concomitant proximal phalangeal dorsiflexion osteotomy, for hallux rigidus between January 2016 and December 2020. Because there were far fewer isolated cheilectomies (62), all C patients were compared with a commensurate number of consecutive CM cases (67) using preoperative, 1-year, and 2-year PROMIS scores for physical function, pain interference, pain intensity, global physical health, global mental health, and depression, as well as complication and revision data from a chart review. A multivariable linear regression analysis was performed to compare adjusted postoperative PROMIS scores between the 2 cohorts. RESULTS: There were no differences between groups among the demographic and preoperative variables compared. The CM cohort reported worse pain interference scores preoperatively (P < .001) and at 1 year postoperatively (P = .01). However, the C cohort reported worse pain intensity scores preoperatively (P < .001) and at 1 year postoperatively (P < .001). Adjusted postoperative PROMIS score comparison demonstrated that the CM cohort had better 1-year postoperative pain intensity scores (P < .05). However, there were no differences between cohorts for additional PROMIS scores or complications data. CONCLUSION: The addition of a Moberg osteotomy does not appear to significantly change short- to medium-term outcomes of cheilectomy for hallux rigidus treatment. LEVELS OF EVIDENCE: Level III: Retrospective comparative study.

Early Periprosthetic Femur Fractures After Primary Cementless Total Hip Arthroplasty: High Risk of Periprosthetic Joint Infection and Subsequent Reoperation.

BACKGROUND: Periprosthetic femur fracture (PFF) following total hip arthroplasty (THA) is a leading cause of early reoperation. The objective of this study was to compare rates of periprosthetic joint infection (PJI) and reoperation following PFFs occurring early postoperatively to those that occurred late. METHODS: We retrospectively identified 173 consecutive surgically managed PFFs following primary THA. Cases were categorized as "early" if they occurred within 90 days of THA (n = 117) or "late" if they occurred following the initial 90 days (n = 56). Mean age at time of PFF was 68 years (range, 26 to 96) and 60% were women. Mean body mass index was 29 (range, 16 to 52). Mean follow-up was 2 years (range, 0 to 13). Kaplan-Meier survival analysis estimated cumulative incidences of PJI and reoperation. RESULTS: Early PFFs had higher 2-year cumulative incidence of PJI (11% versus 0%, P < .001) and reoperation (24% versus 13%, P = .110). Following early PFF, 27 patients required reoperation (ie, 13 for PJI, 5 for instability, 2 for re-fracture, 2 for painful hardware, 2 for non-union, 1 for adverse local tissue reaction, 1 for aseptic loosening, and 1 for leg-length discrepancy). Following late PFF, 5 patients required reoperation (ie, 3 for instability, 1 for re-fracture, and 1 for non-union). CONCLUSIONS: There are greater incidences of PJIs and overall reoperations following early PFFs compared to late PFFs after THA. In addition to focusing efforts on prevention of early PFFs, surgeons should consider antiseptic interventions to mitigate the increased risk of PJI after treatment of early PFF.

Predictors for activity following total and unicompartmental knee arthroplasty.

BACKGROUND: Functional demands of patients undergoing knee arthroplasty are increasing. However, it remains unclear which patient-specific factors have an impact on postoperative activity and whether there is a difference between total and unicompartmental knee arthroplasties (TKA/UKA). MATERIALS AND METHODS: This retrospective study analyzed 1907 knees with TKA (n = 1746) or UKA (n = 161), implanted for primary osteoarthritis. Pain and activity (lower extremity activity scale, LEAS) were assessed 2 years after surgery. High activity was defined as LEAS ≥ 14. Cohorts were compared using Kruskal-Wallis or Pearson-Chi-square test. A generalized least squares model was used to predict LEAS scores between cohorts adjusted for age, sex, BMI, Charlson Comorbidity Index, ASA score, and preoperative LEAS. RESULT: There was no difference in pain 2 years after surgery between UKA and TKA (p = 0.952). Preoperative LEAS was similar for UKA and TKA (p = 0.994), and both groups showed significant (p < 0.001 respectively) and similar improvements after surgery (p = 0.068). LEAS 2 years after surgery was 11.1 (SD 3.2) for TKA and 11.9 (SD 3.5) for the UKA group (p = 0.004). After adjusting for preoperative LEAS, age, sex, BMI, CCI and ASA, the difference was not significant (p = 0.225). Male sex, lower BMI, higher preoperative LEAS, and younger age were associated with higher postoperative LEAS (p < 0.001, respectively). CONCLUSION: Patients can achieve a high level of activity following both TKA and UKA. While the postoperative activity level did not depend on the type of the procedure, younger age, male sex, lower BMI, and a higher preoperative activity level were associated with a higher postoperative activity level.

Association Between Fulfillment of Preoperative Expectations and Diagnosis in Foot and Ankle Surgery.

BACKGROUND: There has been growing interest in patient-reported outcomes in foot and ankle surgery, and the fulfillment of patient expectations is a potentially powerful tool that compares preoperative expectations and perceived postoperative improvement. Prior work has validated the use of expectation fulfillment in foot and ankle surgery. However, given the wide spectrum of pathologies and treatments in foot and ankle, no study has examined the association between expectation fulfillment and specific diagnosis. METHODS: This is a retrospective cohort study consisting of 266 patients who completed the Foot & Ankle Expectations Survey and the Foot and Ankle Outcome Survey (FAOS) preoperatively and 2 years postoperatively. A fulfillment proportion (FP) was calculated using the pre- and postoperative Foot & Ankle Expectations Survey scores. An estimated mean fulfillment proportion for each diagnosis was calculated using a multivariable linear regression model, and pairwise comparisons were used to compare the FP between diagnoses. RESULTS: All diagnoses had an FP less than 1, indicating partially fulfilled expectations. Ankle arthritis had the highest FP (0.95, 95% CI 0.81-1.08), whereas neuromas and mid/hindfoot diagnoses had the lowest FPs (0.46, 95% CI 0.23-0.68; 0.62, 95% CI 0.45-0.80). Higher preoperative expectations were correlated with lower fulfillment proportions. CONCLUSION: FP varied with diagnosis and preoperative expectations. An understanding of current expectation fulfillment among different diagnoses in foot and ankle surgery helps highlight areas for improvement in the management of expectations for presumed diagnoses. LEVEL OF EVIDENCE: Level III, retrospective review of prospective cohort study.

No Difference in the Rate of Periprosthetic Joint Infection in Patients Undergoing the Posterolateral Compared to the Direct Anterior Approach.

BACKGROUND: There remains inconsistent data about the association of surgical approach and periprosthetic joint infection (PJI). We sought to evaluate the risk of reoperation for superficial infection and PJI after primary total hip arthroplasty (THA) in a multivariate model. METHODS: We reviewed 16,500 primary THAs, collecting data on surgical approach and all reoperations within 1 year for superficial infection (n = 36) or PJI (n = 70). Considering superficial infection and PJI separately, we used Kaplan-Meier survivorship to assess survival free from reoperation and a Cox Proportional Hazards multivariate models to assess risk factors for reoperation. RESULTS: Between direct anterior approach (DAA) (N = 3,351) and PLA (N = 13,149) cohorts, rates of superficial infection (0.4 versus 0.2%) and PJI (0.3 versus 0.5%) were low and survivorship free from reoperation for superficial infection (99.6 versus 99.8%) and PJI (99.4 versus 99.7%) were excellent at both 1 and 2 years. The risk of developing superficial infection increased with high body mass index (BMI) (hazard ratio [HR] = 1.1 per unit increase, P = .003), DAA (HR = 2.7, P = .01), and smoking status (HR = 2.9, P = .03). The risk of developing PJI increased with the high BMI (HR = 1.04, P = .03), but not surgical approach (HR = 0.68, P = .3). CONCLUSION: In this study of 16,500 primary THAs, DAA was independently associated with an elevated risk of superficial infection reoperation compared to the PLA, but there was no association between surgical approach and PJI. An elevated patient BMI was the strongest risk factor for superficial infection and PJI in our cohort. LEVEL OF EVIDENCE: III, retrospective cohort study.

Does high activity after total and unicompartmental knee arthroplasty increase the risk for aseptic revision?

INTRODUCTION: It has been suggested that high activity might negatively impact implant survival following total and unicompartmental knee arthroplasty (TKA/UKA) and many surgeons advise their patients to only participate in moderate level sport activities. To date, it remains unclear whether such restraints are necessary to assure longevity of the implants. MATERIALS AND METHODS: We conducted a retrospective study on 1906 knees (1745 TKA, 161 UKA) in 1636 patients aged 45-75 years who underwent primary arthroplasty for primary osteoarthritis. Lower extremity activity scale (LEAS) at a two year follow-up was assessed to define the activity level. Cases were grouped in low (LEAS ≤ 6), moderate (LEAS 7-13) and high activity (LEAS ≥ 14). Cohorts were compared with Kruskal-Wallis- or Pearson-Chi2-Test. Univariate logistic regression was conducted to test for association between activity level at two years and later revisions. Odds ratio was reported and converted to predicted probability. A Kaplan-Meier curve was plotted to predict implant survival. RESULTS: The predicted implant survival for UKA was 100.0% at two years and 98.1% at five years. The predicted implant survival for TKA was 99.8% at two years, 98.1% at five years. The difference was not significant (p = 0.410). 2.5% of the UKA underwent revision, one knee in the low and three knees in the moderate activity group, differences between the moderate and high activity group were not significant (p = 0.292). The revision rate in the high activity TKA group was lower than in the low and moderate activity groups (p = 0.008). A higher LEAS two years after surgery was associated with a lower risk for future revision (p = 0.001). A one-point increase in LEAS two years after surgery lowered the odds for undergoing revision surgery by 19%. CONCLUSIONS: The study suggests that participating in sports activity following both UKA and TKA is safe and not a risk factor for revision surgery at a mid-term follow-up. Patients should not be prevented from an active lifestyle following knee replacement.

Significantly Worse Fixation of Cemented Patellar Components on Multiacquisition Variable-Resonance Image Combination Magnetic Resonance Imaging Compared to Femoral and Tibial Components: A Cause for Concern?

BACKGROUND: The etiology of anterior knee pain after total knee arthroplasty (TKA) remains unclear. Few studies have examined patellar fixation quality. The purpose of the present study was to evaluate the patellar cement-bone interface after TKA on magnetic resonance imaging (MRI) and to correlate the patella fixation grade with the incidence of anterior knee pain. METHODS: We retrospectively reviewed 279 knees undergoing metal artifact reduction MRI for either anterior or generalized knee pain at least 6 months after cemented, posterior-stabilized TKA with patellar resurfacing with one implant manufacturer. MRI cement-bone interfaces and percent-integration of the patella, femur, and tibia were assessed by a fellowship-trained senior musculoskeletal radiologist. The grade and character of the patella interface were compared to the femur and tibia. Regression analyses were used to determine the association between patella integration with anterior knee pain. RESULTS: There were more patellar components with ≥75% zones of fibrous tissue (50%) compared to the femur (18%) or tibia (5%) (P < .001). There were a greater number of patellar implants with poor cement integration (18%) compared to the femur (1%) or tibia (1%) (P < .001). MRI findings showed more evidence of patellar component loosening (8%) compared to the femur (1%) or tibia (1%) (P < .001). Anterior knee pain was correlated with worse patella cement integration (P = .01), with women predicted to have better integration (P < .001). CONCLUSION: The quality of the patellar cement-bone interface after TKA is worse compared to the femoral or tibial component interface. Poor patellar cement-bone interface may be a source of anterior knee pain after TKA, but further investigation is required.

COVID-19 disruptions to elective postoperative care did not adversely affect early complications or patient reported outcomes of primary TKA.

INTRODUCTION: Elective orthopedic care, including in-person office visits and physical therapy (PT), was halted on March 16, 2020, at a large, urban hospital at the onset of the local COVID-19 surge. Post-discharge care was provided predominantly through a virtual format. The purpose of this study was to assess the impact of postoperative care disruptions on early total knee arthroplasty (TKA) outcomes, specifically 90-day complications, 120-day rate of manipulation under anesthesia (MUA) and 1-year patient-reported outcome measures (PROMs). MATERIALS AND METHODS: Institutional records were queried to identify 624 patients who underwent primary, unilateral TKA for osteoarthritis and who were discharged home between 1/1/20 and 3/15/20. These patients were compared to 558 controls discharged between 1/1/19 and 3/15/2019. Cohort demographics and in-hospital characteristics were equivalent apart from inpatient morphine milligram equivalent (MME) consumption. Patient-reported access to PT (p < 0.001) and post-discharge care (p < 0.001) were worse among study patients. Study patients were prescribed fewer post-discharge PT sessions (19.8 vs. 23.5; p < 0.001) and utilized telehealth more frequently (p < 0.001). Mann-Whitney U, T, Fisher's Exact, and chi-squared tests were used to compare outcomes. RESULTS: Ninety-day CMS complications were lower among study patients (3.5% vs. 5.9%; p = 0.05). Rates of MUA were similar between groups. Study patients reported similar PROMs and marginally inferior VR-12 mental and LEAS functional outcomes at 1 year. CONCLUSION: Disruptions to elective orthopedic care in March 2020 seemed to have had no major consequences on clinical outcomes for TKA patients. Our findings question the usefulness of pre-pandemic post-discharge protocols, which may over-emphasize in-person visits and PT.

Assessment of Flatfoot Deformity Using Digitally Reconstructed Radiographs: Reliability and Comparison to Conventional Radiographs.

BACKGROUND: Digitally reconstructed radiographs (DRRs) generated from weightbearing computed tomography (WBCT) may potentially substitute for weightbearing plain radiographs (XRs) but have not been clinically validated. This study aims to test the reliability of 6 radiographic parameters of progressive collapsing foot deformity (PCFD) as measured on DRR, to investigate whether DRR represents comparably to XR through the same measurements, and to compare agreement of DRR and XR measurements of a standardized arch height parameter with reference measurements made on WBCT. METHODS: DRR generated from preoperative WBCT of 71 patients (72 feet) treated surgically for PCFD were retrospectively compared with preoperative weight-bearing XR after exclusion criteria were applied. Six radiographic measurements were performed, including Meary angle, calcaneal pitch (CPA), medial cuneiform height (MCH), AP talar-first metatarsal angle (T-1MT), talonavicular coverage (TNCA), and talar incongruency (TIA). Arch height was measured on XR, DRR, and WBCT using a validated, standardized, navicular-based index. Intraclass correlation coefficients assessed DRR intraobserver and interobserver reliability. Paired samples t tests tested differences between XR and DRR. Bland-Altman limits of agreement analysis compared DRR and XR agreement with WBCT measurements. RESULTS: Measurements were within standard PCFD ranges on XR and DRR. All measurements demonstrated excellent intrarater reliability and good to excellent interrater agreement, consistent with previous literature on XR. No differences were found for Meary, CPA, or TNCA. Minor differences were observed for MCH, T-1MT, and TIA. DRR measurements demonstrated greater agreement with WBCT than XR measurements. CONCLUSION: DRR from WBCT may be a promising substitute for XR in the clinical evaluation of PCFD. Radiographic measurements made on DRR demonstrated good to excellent reliability. Although small differences were found between XR and DRR for certain measurements, DRR more accurately represented medial arch anatomy compared to gold standard WBCT data than XR. If validated as a clinical substitute, DRR could eventually obviate XR where WBCT is available. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Return to Physical Activity Following Flatfoot Reconstruction.

BACKGROUND: Progressive collapsing foot deformity (PCFD) is a debilitating condition encompassing several interrelated, progressive deformities requiring a combination of reconstructive procedures. Few studies investigate returns to activity following flatfoot reconstruction, and existing studies only examine 1 or 2 of the numerous procedures employed. This study aims to provide the first generalizable assessment of returns to sports and physical activity following reconstruction surgery in patients with flexible flatfoot deformity. METHODS: Patients aged 18-60 years who underwent reconstructive surgery between February 16 and May 19 for symptomatic flexible-stage flatfoot deformity were identified by registry review. Eighty-two of 113 eligible patients (73%) were reached at a mean 2.9 years (range, 2.0-5.4) of follow-up with mean age at surgery of 48.9 years (range, 18-59). Returns to physical activity were evaluated with a sports-specific survey. Clinical outcomes were evaluated with Patient-Reported Outcomes Measurement Information System (PROMIS) scores. RESULTS: Patients reported participation in 21 specific sports and activities. One-fourth (25.6%) of patients (21/82) reported increased difficulty with physical activities postoperatively, 15.9% reported equal difficulty, and 58.5% (48/82) reported decreased difficulty. Median return times were 9-12 months for participation and 12-18 months to reach maximum preoperative participation levels. Improvements in Physical Function (P= .001), Pain Interference (P < .001), Pain Intensity (P <.001), and Global Physical Health (P = .004) were associated with increased satisfaction with respect to sports and physical activities. DISCUSSION: This study investigated participation in specific sports and physical activities following flatfoot reconstruction. Our findings suggest mixed outcomes, where many patients reported life-changing improvements but many also experienced prolonged pain and difficulty after surgery. Some patients reported increased difficulty or inability to return to their preoperative maximum level of participation, indicating that flatfoot reconstructions can lead to athletic limitations. CONCLUSION: Although flatfoot reconstruction can be a powerful tool to increase patients' capacity to engage in physical activity, in our cohort many patients had reduced physical activity outcomes. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Preoperative PROMIS Physical Function Scores Predict Postoperative Outcomes Following Total Ankle Replacement.

BACKGROUND: Despite good evidence that supports significant improvements in pain and physical function following a total ankle replacement (TAR) for end-stage ankle arthritis, there is a subset of patients who do not significantly benefit from surgery. The purpose of this study was to perform a preliminary analysis to determine if preoperative Patient-Reported Outcome Measurement Information System (PROMIS) scores could be used to predict which patients were at risk of not meaningfully improving following a TAR. METHODS: Prospectively collected preoperative and ≥2-year postoperative PROMIS physical function, pain interference, pain intensity, and depression scores for 111 feet in 105 patients were included in the study. Significant postoperative improvement was defined using minimal clinically important differences (MCIDs). Logistic regression models and area under the curve (AUC) analyses were used to determine whether preoperative PROMIS scores were predictive of postoperative outcomes. RESULTS: Receiver operating characteristic curves found statistically significant AUCs for the PROMIS physical function (AUC = 0.728, P = .004), pain intensity (AUC = 0.720, P = .018), and depression (AUC = 0.761, P < .001) domains. The preoperative PROMIS pain interference domain did not achieve a statistically significant AUC. CONCLUSION: Preoperative PROMIS physical function and pain intensity t scores may be used to predict postoperative improvement in patients following a fixed-bearing TAR; however, preoperative PROMIS pain interference scores were not good predictors. The results of this study may be used to guide research regarding patient-reported outcomes following TAR. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Have newer bearing surfaces changed expectations regarding the longevity of total hip arthroplasty?

AIMS: The purpose of this study is to examine six types of bearing surfaces implanted at a single institution over three decades to determine whether the reasons for revision vary among the groups and how long it takes to identify differences in survival. METHODS: We considered six cohorts that included a total of 1,707 primary hips done between 1982 and 2010. These included 223 conventional polyethylene sterilized with γ irradiation in air (CPE-GA), 114 conventional polyethylene sterilized with gas plasma (CPE-GP), 116 crosslinked polyethylene (XLPE), 1,083 metal-on-metal (MOM), 90 ceramic-on-ceramic (COC), and 81 surface arthroplasties (SAs). With the exception of the COC, all other groups used cobalt-chromium (CoCr) femoral heads. The mean follow-up was 10 (0.008 to 35) years. Descriptive statistics with revisions per 100 component years (re/100 yr) and survival analysis with revision for any reason as the endpoint were used to compare bearing surfaces. RESULTS: XLPE liners demonstrated a lower cumulative incidence of revision at 15 years compared to the CPE-GA and CPE-GP groups owing to the absence of wear-related revisions (4% for XLPE vs 18%, p = 0.02, and 15%, p = 0.003, respectively). Revisions for adverse local tissue reactions occurred exclusively among the MOM (0.8 re/100 year) and SA groups (0.1 re/100 year). The revision rate for instability was lower among hips with 36 mm and larger head sizes compared to smaller head sizes (0.2% vs 2%, p < 0.001). CONCLUSION: The introduction of XLPE has eliminated wear-related revisions through 15-year follow-up compared to CPE-GP and CPE-GA. Dislocation incidence has been reduced with the introduction of larger diameter heads but remains a persistent concern. The potential for adverse local tissue reactions with MOM requires continued follow-up. Cite this article: Bone Joint J 2020;102-B(7 Supple B):105-111.

Narcotic Consumption in Opioid-Naïve Patients Undergoing Total Hip and Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is associated with increased risk of prolonged narcotic requirement compared to total hip arthroplasty (THA). This study aims to compare acute postoperative narcotic consumption between the 2 procedures and quantify amount of narcotics used by opioid prescribed. METHODS: From October 2017 to August 2019, patients were surveyed at 4-week follow-up to determine amount and duration of opioids used and whether they continued to require narcotics. Among 1332 patients who self-identified as opioid naïve, 670 underwent THA and 662 underwent TKA. Descriptive analysis was performed based on data type. RESULTS: The total morphine equivalent dose (MED) used in the postoperative period was lower in THA than in TKA (143 ± 160 vs 259 ± 250 MED, P < .001). The duration of use was shorter, total amount of pills consumed was lower, and refill rates were less in THA compared to TKA regardless of which opioid was prescribed. A smaller proportion of patients required narcotics at 4-week follow-up in THA compared to TKA. A postoperative prescription of 45 pills of any one type of narcotic was sufficient for nearly 90% of THA patients, and 60 pills of any one type of narcotic was appropriate for over 75% of TKA patients. CONCLUSION: THA is associated with less total narcotic consumption, shorter duration of use, less refills, and lower likelihood of requiring narcotics at 4-week follow-up. Percentiles of total narcotics consumed are provided to promote judicious postoperative prescribing patterns, and one could consider further reducing narcotics when utilizing our protocol, particularly for THA patients. LEVEL OF EVIDENCE: This is a level III retrospective cohort study reviewing narcotic use in over 900 consecutive opioid-naïve patients undergoing total hip and knee arthroplasty.

Narcotic Consumption in Opioid Naïve Patients Undergoing Unicompartmental and Total Knee Arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is associated with increased risk of prolonged narcotic requirement compared to unicompartmental knee arthroplasty (UKA). The purpose of the current study is to compare acute postoperative narcotic consumption between the 2 procedures and quantify narcotic consumption. METHODS: From October 2017 to August 2019 patients were surveyed for four weeks to determine the amount and duration of opioids consumed and requirement for continued narcotics. Among 976 opioid naïve patients, 314 (32%) underwent UKA and 662 (68%) underwent TKA. Patients were analyzed according to specific narcotic prescribed. Total morphine equivalent dose (MED), number of pills, duration, refill percentage, and usage percentage for 4 weeks were calculated for each procedure. RESULTS: MED used in the postoperative period was lower in patients undergoing UKA than TKA (200 ± 195 vs 259 ± 250 MED, P = .002). Total number of pills consumed and duration of use was less in UKA compared to TKA regardless of which opioid was prescribed. A smaller proportion of patients required narcotics for 4 weeks after UKA (32% vs 43%, P < .001), and fewer UKA patients required narcotic refills (14% vs 27%, P < .001). Sixty pills of any 1 type of narcotic was sufficient for 90% of UKA patients and over 75% of TKA patients. CONCLUSION: UKA is associated with less narcotic consumption, shorter duration of use, less refills, and lower likelihood of narcotic requirement for 4 weeks. We report narcotic consumption patterns for both procedures to aid surgeons in judicious postoperative prescribing. LEVEL OF EVIDENCE: This is a level III retrospective cohort study reviewing narcotic use in over 900 consecutive opioid naïve patients undergoing UKA or TKA.

CtBP-a targetable dependency for tumor-initiating cell activity and metastasis in pancreatic adenocarcinoma.

Ctbp2 is a uniquely targetable oncogenic transcriptional coregulator, exhibiting overexpression in most common solid tumors, and critical to the tumor-initiating cell (TIC) transcriptional program. In the "CKP" mouse pancreatic ductal adenocarcinoma (PDAC) model driven by mutant K-Ras, Ctbp2 haploinsufficiency prolonged survival, abrogated peritoneal metastasis, and caused dramatic downregulation of c-Myc, a known critical dependency for TIC activity and tumor progression in PDAC. A small-molecule inhibitor of CtBP2, 4-chloro-hydroxyimino phenylpyruvate (4-Cl-HIPP) phenocopied Ctbp2 deletion, decreasing tumor burden similarly to gemcitabine, and the combination of 4-Cl-HIPP and gemcitabine further synergistically suppressed tumor growth. Pharmacodynamic monitoring revealed that the 4-Cl-HIPP/gemcitabine combination induced robust and synergistic tumor apoptosis and marked downregulation of the TIC marker CD133 in CKP PDAC tumors. Collectively, our data demonstrate that targeting CtBP represents a fruitful avenue for development of highly active agents in PDAC that cooperate with standard therapy to limit both primary and metastatic tumor burden.

An intestinal stem cell niche in Apc mutated neoplasia targetable by CtBP inhibition.

C-terminal binding protein 2 (CtBP2) drives intestinal polyposis in the Apcmin mouse model of human Familial Adenomatous Polyposis. As CtBP2 is targetable by an inhibitor of its dehydrogenase domain, understanding CtBP2's role in adenoma formation is necessary to optimize CtBP-targeted therapies in Apc mutated human neoplasia. Tumor initiating cell (TIC) populations were substantially decreased in ApcminCtbp2+/- intestinal epithelia. Moreover, normally nuclear Ctbp2 was mislocalized to the cytoplasm of intestinal crypt stem cells in Ctbp2+/- mice, both Apcmin and wildtype, correlating with low/absent CD133 expression in those cells, and possibly explaining the lower burden of polyps in Apcmin Ctbp2+/- mice. The CtBP inhibitor 4-chloro-hydroxyimino phenylpyruvate (4-Cl-HIPP) also robustly downregulated TIC populations and significantly decreased intestinal polyposis in Apcmin mice. We have therefore demonstrated a critical link between polyposis, intestinal TIC's and Ctbp2 gene dosage or activity, supporting continued efforts targeting CtBP in the treatment or prevention of Apc mutated neoplasia.