Methods

We identified 664,761 THRs in the NJR. The exposure was the unit in which the THR was implanted and the outcome all-cause revision. Net failure was estimated using Kaplan-Meier and adjusted analyses used flexible parametric survival analysis.

Methods

A total of 4126 consecutive THAs were reviewed for patients between 2006 and 2012 to allow for a minimum five-year follow-up. To determine the effects of the stem alignment on results, the hips were classified into 3 groups on the basis of stem alignment in initial postoperative anteroposterior radiographs. The alignment of the stem was defined as neutral, valgus (≥ 3° of lateral deviation), or varus (≥ 3° of medial deviation). The primary outcome was all cause revision with patient related outcomes assessed with Oxford hip score pre and post-operatively.

Methods

Patients awaiting THA were fitted with a bespoke device consisting of a 3D-printed clamp which housed the IMU and positioned over the sacrum. A wide elastic belt was fitted around the patient's waist to keep the device in place. Movement data was transmitted wirelessly to a tablet computer. Pelvic tilt was measured in standing, flexed seated and step-up positions while undergoing X-rays with the IMU capturing the data in parallel. Statistical analysis included measures of correlation between the X-ray and IMU measurements.

Methods

Taperfit (ODEP 10A) is a polished, collarless, double tapered stem available in multiple sizes/offsets. Trinity is a hemispherical porous titanium cementless shell. A prospective audit of implant size was performed for the first 50 cases. Based on these findings, instruments were reduced to a single tray per component based on predicted size, named ‘Corin Hip for the Osteoarthritic Patient’ (CHOP). A further re-audit was performed to confirm correct tray constituent sizes. Financial data were calculated using known TSSU costs of approximately £50 per tray.

Patients/Materials & Methods

41 consecutive patients presenting with a hip fracture on therapeutic dose DOAC were identified. Anti- factorXa levels were collected at 24hours and repeated at 48hours if elevated. We investigated if renal function or clotting screen could help predict safe time to surgery.

Materials and methods

We investigated 16 retrieved acetabular cups divided into ‘3D printed’ (n = 6; Delta TT) and ‘conventional’ (n = 10; Pinnacle Porocoat). The groups were matched for age, time to revision, size and gender (Table 1). Reasons for revision included unexplained pain, aseptic loosening, infection and ARMD. Visual inspection was performed to evaluate tissue attachment. Micro-CT was used to assess clinically relevant morphometric features of the porous structure, such as porosity, depth of the porous layer, pore size and strut thickness. Scanning electron microscopy (SEM) was applied to evaluate the surface morphology.

Methods

We employed a modified Delphi method with four expert surgeons from three international centres of excellence. Surgeons were independently observed performing THA before undergoing semi-structured cognitive task analysis (CTA) before completing successive rounds of electronic surveys until consensus. The agreed CTA was incorporated into a mobile and web-based platform. Forty surgical trainees (CT1-ST4) were randomised to CTA-training or a digital op-tech with surgical videos, before performing a simulated DAA THA in a validated fully-immersive virtual reality simulator.

Methods

At our unit all patients undergoing revision of a MoM hip prosthesis have periprosthetic tissue samples graded for ALVAL. Explants undergo volumetric wear testing of the bearing and taper surfaces. We identified patients with moderate/severe ALVAL who had been exposed to lower than the median wear rate of all recorded patients who had developed ALVAL (<3mm³/year). This was termed the “ALVAL” group. We then identified all patients whose tissues had shown no signs of ALVAL. The patients in the two groups were sent buccal DNA collection kits. DNA was examined using next generation sequencing. Alleleic frequencies in the two groups were compared using Fisher's test and compared to a background UK population group (n=8514). We then conducted binary logistic regression with patient age, sex, primary source of debris (taper/bearing) and HLA genotype as the predictors. With the hypothesis that a cobalt/albumin metalloprotein acts as the epitope, we used validated binding prediction software to determine the relative affinities of the binding grooves created by different DQA1/DQB1 genetic combinations for albumin derived peptides. Given the protection that male sex and younger age appears to confer against ALVAL, we hypothesized that testosterone peptides may compete for these binding sites.

Methods

A computer-based systematic search followed the PRISMA Guidelines (8) was performed using the 6 most comprehensive databases (CENTRAL, PUBMED, EMBASE, SCOPUS, EBSCO, Google Scholar and Web of Science) and included all published studies from inception until November 1^st 2018. Weighted means were calculated for the rate of RTP and duration and for patient reported outcome measures (PROMs).

Objectives

The primary objective was to determine the success of joint preservation after hip arthroscopy. The secondary objective was to determine whether patient characteristics or PROM functional score trends could predict revision hip arthroscopy or Total Hip Arthroplasty (THA).

Methods

UK National Joint Registry is the largest registry of its kind in the world. This study included 2934 patients with 5868 THAs who underwent bilateral THAs s between 2003 and 2016. These patients had undergone bilateral sequential THAs within 3 years of each other: cemented THA on one side and cementless on the other, Patients had identical pre-operative American Society of Anaesthesiologists group for both THAs and same indication for surgery. Implant survival was compared using Cox regression with an endpoint of stem revision.

Patients and Methods

We performed a retrospective observational study involving 60,812 THAs (12.4%=smokers, 31.2%=ex-smokers, 56.4%=non-smokers) from the Clinical Practice Research Datalink. Data were linked with Hospital Episode Statistics and the Office for National Statistics to identify outcomes. The effect of smoking on post-operative outcomes (complications, medications, revision, mortality, PROMs) was assessed using adjusted regression.

Methods

Consecutive patients undergoing THA in Exeter between 1996 and 2012 had OHS' collected prospectively pre-operatively and a minimum of 4 years post-operatively. These scores were analysed looking for trends in patient related outcome scores.

Method

Patients listed for hip arthroplasty were pre-assessed according to the Charlson-Comorbidity-index (CCI) in May 2017. Demographic data, established risk factors and preoperative renal-function were collected. Pre-existing renal dysfunction was classified using KDIGO CKD criteria. RIFLE AKIN scores were used to document post-operative renal impairment based on 7-day serum creatinine. Renal function was assessed at 30 day and 1 year. Risk for early and long-term-complications were determined by univariate and multivariate analysis. Mortality and kidney-disease-progression were estimated using Kaplan Meier plots

Patients, materials and methods

337 647 primary THAs from the National Joint Registry (UK) were included in a multivariable survival and regression analysis to identify the adjusted hazard of PFF revision following primary THA using cementless stems. The effect of a collar in cementless THA on early PFF was evaluated in an in-vitro model using paired fresh frozen cadaveric femora.

Objectives

The aim of the study was to determine the impact of pre-operative depression on patient functional outcomes and satisfaction rates after THA. A secondary objective was to assess potential change in the incidence of depression at mid-term post-operative follow-up.

Methods

A retrospective review of electronic records of 1337 cases who underwent THR using the Corail stem was carried out. 1204 (Collared 1042, Uncollared 162) had a minimum follow up of 1 year, 693 of those had a follow up of at least 5 years. Radiological review was carried out by 2 independent investigators.

Methodology

We conducted a retrospective study of data collected from National Joint Registry for England and Wales, Northern Ireland and the Isle of Man between 1^st September 2005 until 31^st August 2017. A logistic regression analysis model was used to investigate the association between ALBC versus plain cement and the odds ratio (OR) for revision, adjusting for age, ASA grade, bearing surfaces, head size and cup and stem fixation. Indications for revision recorded in NJR were considered in separate models.

Methods

We retrospectively evaluated all non-navigated THAs performed at our institution from 2006–2016. Case-notes were reviewed for dichotomised satisfaction score, LOS and radiographic parameters including inclination, anteversion, limb length discrepancy (LLD) and offset discrepancy. Patients were classified into 4 groupings based on BMI (underweight (<24.5), healthy (24.5–30), obese (30–40), severely obese (>40)). Appropriate statistical analyses were performed to identify between group differences.

Methods

Patients were identified from theatre records. Electronic and paper notes were reviewed.

Methods

Eighteen surgical trainees (CT1-ST4) with no prior experience of direct anterior approach (DAA) THA completed an intensive 1-day course (lectures, dry-bone workshops and technique demonstrations). They were randomised to either a 5-week protocol of VR simulator training or conventional preparation (operation manuals and observation of real surgery). Trainees performed DAA-THA on cadaveric hips, assisted by a passive scrub nurse and surgical assistant. Performance was measured on the Intercollegiate Surgical Curriculum Project (ISCP) procedure-based assessment (PBA), on a 9-point global summary score (Table 1). This was independently assessed by 2 hip surgeons blinded to group allocation. The secondary outcome measure was error in cup orientation from a predefined target (40° inclination and 20° anteversion).

Patients/Materials & Methods

Retrospective analysis of 343 hip aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre-operative aspiration is routine.

Objectives

The objective was to determine the seroprevalence of HIV in patients presenting for THA in an academic institution in a developing country. Secondarily, the aim was to determine if there is any difference in the seroprevalence of patients undergoing THA and TKA and finally to assess the status of disease control in seropositive patients eligible for TJA on pre-existing HAART.

Materials and methods

Hundred and eighteen consecutive cemented revision THAs with minimum follow up of 5 years following primary diagnosis of DDH operated by a single unit between January 1974 and December 2012 were analysed for their clinical and radiological outcomes.

Patients/Materials and Methods

Prospective study with patients recruited in clinic when listed for THR surgery. Patients are emailed login details for the web based electronic resource system (GoWellHealth). The platform delivers content in a time-lined fashion and is individualised to the patient. Data gathered includes the number of patients registering to use this system, their engagement and use of the resources, and results from forms and questionnaires administered.

Methods

A single-centre, retrospective cohort study was performed on a group of patients (n=183) with acetabular retroversion (n=90) or lateral-under-coverage dysplasia (n=93) treated with PAO. Acetabular deformity was defined on pelvic radiographs and 3-D CTs using a number of parameters. Hips with retroversion, were sub-divided into combined pathology - retroversion with dysplasia (lateral centre-edge [LCEA] < 25°), or retroversion-only (LCEA≥25°). The mean age at time of the procedure was 29+/−7 years and most hips were in females (n=171). Complication (as per Dindo-Clavien)-, re-operation-, hip preservation rates and patient-reported-outcome measures were measured using the Non-Arthroplasty-Hip-Score (NAHS).

Methods

PT was measured for 51 patients who underwent a successful PAO. Mean age at PAO was 29±6 years and 48 were females. PT, pelvic incidence (PI), anterior pelvic plane (APP), and sacral slope (SS) were measured from CT data in 23 patients and compared to 44 (32±7 years old, 4 females) asymptomatic volunteers. Change in pelvic tilt in all 51 patients was measured using the Sacro-Femoral-Pubic angle (SFP), a validated method, from pre- and post-operative radiographs at a mean interval of 2.5(±2) years.

Patients and Methods

A retrospective observational study was performed using data collected prospectively by the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. All primary stemmed THAs implanted for hip fractures between 2003–2015 were eligible for inclusion (n=19,432). The two surgical approach groups (posterior versus anterolateral) were propensity-score matched for multiple potential patient and surgical confounding factors (n=14,536, with 7,268/group). Outcomes (implant survival, patient survival, intraoperative complications) were compared between the approach groups using regression analysis.

Methods

A five-year retrospective analysis of all patients receiving THA for displaced intracapsular hip fractures from 2013–18 was performed. Data was collected from the institutions' hip fracture database, including data submitted to the National Hip Fracture Database (NHFD). Cox regression analysis and log-rank tests were implemented to evaluate factors associated with THA dislocation. Patient age, sex, ASA grade, surgeon seniority, surgical approach, femoral head diameter and acetabular cup type were all investigated as independent factors.

Methods

All patients admitted with an acute neck of femur fracture were grouped into three cohorts, depending on provision of 7DPOT services: the initial cohort received 5DPOT between December 2012 and March 2013. Seven-day physiotherapy and occupational therapy was introduced for one year from October 2014 until September 2015 (2^nd cohort). The service then reverted to 5DPOT between January to June 2016 (3^rd cohort). The third cohort was utilised to nullify changes in the overall service which had occurred which were not attributable to 7DPOT. Data was collected prospectively using a specially designed audit tool.

Method

We ran a prospective, 2 arm, single blinded, randomised control trial comparing focused shockwave therapy to an ultrasound guided corticosteroid injection. The primary outcome measure was the visual analogue pain score. Secondary outcome measures included the Harris hip score and Trendelenburg test for function; the SF-36 for quality of life (QoL); and a Likert scale question for a subjective assessment of symptom improvement.

Methods

Post-operative CT scans and lateral standing and seated radiographs of 40 THA patients were performed, 20 of whom had experienced postoperative dislocation. The changes in pelvic and femoral positions on the lateral radiographs were measured between the standing and seated positions, and a 3D digital model was then generated to simulate the movement of the hip when rising from a chair for each patient. The path of the joint reaction force (JRF) across the acetabular bearing surface and the motion of the femoral neck relative to the acetabular margin were then calculated for this “sit-to-stand” movement, in order to identify where there was risk of edge loading or prosthetic impingement.

Objectives

Our aim was to compare the biomechanics of periprosthetic fractures around the CPT and Exeter V40 stems in a composite saw bone model to identify if a difference in fracture risk exists between the two stems. We also compared the engineering design of the two implants in order to analyse the possible effect this may have on fracture risk.

Methods

Data was collected prospectively on 419 consecutive replacements (390 patients), performed between March 2000 and February 2005. A posterior approach was used, and the acetabulum was prepared with multiple key holes. Palacos-R bone cement containing Gentamicin was used with a cement pressuriser.

Methods

This retrospective cohort study included 793823 primary THAs between 2004 and 2016. Relative risks for patient, surgical and implant factors are estimated for any IOPFF fracture and for all anatomical subtypes of IOPFF.

Patients and Methods

This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m² and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (sd 6.5)) were enrolled. All patients had a minimum of two years’ clinical follow-up. Patient-reported outcome measures, whole blood metal ion levels (ug/l), and periprosthetic femoral BMD were measured at baseline, as well as at one and two years postoperatively. Power analysis indicated 40 patients necessary to demonstrate a five-fold increase in cobalt levels from baseline (alpha = 0.05, beta = 0.80). A mixed model with repeated measures was used for statistical analysis.

Methods

For part A, we included all revision surgeries carried out at our unit with the relevant data, including volumetric wear analysis, joint fluid (JF) Co and Cr concentrations, and ALVAL grade (n = 315). Receiver operating characteristic curves were constructed to assess the reliability of the CoCr JFR in identifying severe ALVAL and/or SOTP. For part B, we included only patients with unilateral prostheses who had given matched serum and whole blood samples for Co and Cr analysis (n = 155). Multiple regression was used to examine the influence of JF concentrations on the serum partitioning of Co and Cr in the blood.

Methods

A total of 92 retrieved MoM Pinnacle hips were analyzed, of which 45 were implanted before 2007, and 47 from 2007 onwards. The ‘pre-2007’ group contained 45 implants retrieved from 21 male and 24 female patients, with a median age of 61.3 years (interquartile range (IQR) 57.1 to 65.5); the ‘2007 onwards’ group contained 47 implants retrieved from 19 male and 28 female patients, with a median age of 61.8 years (IQR 58.5 to 67.8). The volume of material lost from their bearing and taper surfaces was measured using coordinate and roundness measuring machines. These outcomes were then compared statistically using linear regression models, adjusting for potentially confounding factors.

Methods

A retrospective chart review was conducted on a consecutive series of 411 primary bilateral DA-THAs performed between 2010 and 2016 at a single institution by two fellowship trained surgeons. These were categorized as: (1) simultaneous (same anesthesia, n=122) and (2) staged (different hospitalizations, n=289). The mean time between staged surgeries was 468 days (± 414 days). Baseline patient demographics as well as hospital LOS, discharge disposition (home vs. other), hospital adverse events (i.e., nausea, vomiting, tachycardia, fever, confusion, pulmonary embolism, etc.), blood transfusions, and unplanned hospital readmissions and reoperations within 90 days were collected. Groups were compared using independent –tests, Fisher's exact test, and Pearson Chi-Square.

Methods

Review the literature produced registry data and controlled studies data establishing that XLPE reduced the “all cause” revision rate over the first 15 years of follow-up of total hip replacements at least in half, and often more.

A conservative estimate of the number of revisions annually in the United States is 50,000. A conservative estimate of the average, integrated cost for a THR revision in the United States is $50,000, meaning that the costs of these revisions annually is at least $2.5 billion.

Using a very conservative figure of just 40% for the percent reduction in revision surgery resulting from the use of XLPE reduces this burden by at least $1 billion annually.

Methods

Following IRB approval with informed consent, self-reported asymptomatic primary COP and HRA patients greater than one year post arthroplasty were evaluated with 4 annual (TP1–4) MRIs using a standardized protocol and serum ion level testing. Morphologic and susceptibility reduced images were acquired for each hip and evaluated for synovial thickness, volume, capsule dehiscence and the presence of ALTR. Patient reported outcomes were evaluated by Hip Disability and Osteoarthritis Outcome Scores (HOOS). Analyses were performed to detect differences of synovial thickness and volume, and HOOS subgroups between and within bearing surfaces at each time point and over time, and to compare the time to and the risk of developing MRI ALTR. Analyses were adjusted for age, gender, and length of implantation.

Methods

A single-center tertiary care departmental database was queried for all cases of osteoid osteoma seen between Jan 1, 2003 and December 31, 2015. Medical records were reviewed to identify those with lesions identified within or around the hip joint. Clinical, demographic, and radiologic data were analyzed.

Methods

We conducted a descriptive analysis of adult patient encounters with a primary diagnosis of osteoarthritis during a one-year time period from Jan –Dec 2016 at a large, healthcare system. Demographic data, prescription data, patient-specific prescription drug use risk criteria were collected. Descriptive analysis was conducted to characterize the population of arthritis patients who received prescription opioids. The rate of controlled substance prescribing was calculated for the population as a whole and among subgroups (age, facility type, and patient risk profile).

Introduction

Total joint arthroplasty (TJA) candidates have historically received high doses of opioids within the perioperative period for the management of surgical pain. Healthcare systems have responded by improving opioid prescribing documentation and implementing narcotic-sparing pain protocols into TJA integrate care pathways (ICP). Despite these efforts, there are few technological platforms designed to curtail excessive inpatient narcotic administration. Here we present an early iteration of an inpatient narcotic administration reporting tool which normalizes patient narcotic consumption as an average daily morphine milligram equivalence (MME) per surgical encounter (MME/day/encounter) among total hip arthroplasty (THA) recipients. This information may help orthopaedic surgeons visualize their individual granular inpatient narcotic prescribing habits individually and compared to other surgeons, while taking into consideration patient and procedure specific variables.

Methods

The mathematical criteria for radiographic measurement of anatomic I&A are defined as well as the mathematical relationships and discrepancies between anatomic and radiographic I&A for any given cup.

$$\begin{array}{c}A=Angle\hspace{0.17em}of\hspace{0.17em}anteversion\hspace{0.17em}of\hspace{0.17em}cup\\ I=Angle\hspace{0.17em}of\hspace{0.17em}inclination\hspace{0.17em}of\hspace{0.17em}cup\end{array}$$

E = Angle of ellipse major diameter to horizontal

E = Radiographic inclination

$$\begin{array}{l}\text{Sin}\hspace{0.17em}A=\frac{Horizontal\hspace{0.17em}width\hspace{0.17em}of\hspace{0.17em}ellipse}{Length\hspace{0.17em}of\hspace{0.17em}ellipse\hspace{0.17em}major\hspace{0.17em}diameter}\hfill \\ \text{Sin}\hspace{0.17em}I=\frac{Vertical\hspace{0.17em}height\hspace{0.17em}of\hspace{0.17em}ellipse}{Length\hspace{0.17em}of\hspace{0.17em}ellipse\hspace{0.17em}major\hspace{0.17em}diameter}\hfill \end{array}$$

Tan I = Tan E / Cos A

Tan E = (Tan I) x (Cos A)

Methods

The outcomes of 37 consecutive hip abductor tendon repairs treated between January 2009 and December 2017 were retrospectively reviewed. Large tears were defined as detachment of 33–100% of the gluteus medius insertion. There were 15 DSF and 10 BT cases. Postoperative pain, ability to perform single leg stance, hip abduction, and Trendelenburg lurch, were examined. Small tears (12 cases) were defined as having no gluteus medius avulsion from the trochanteric insertion and were comprised of longitudinal tears (repaired side-by-side) and isolated gluteus minimus tears (repaired by tenodesis to the overlying gluteus medius). Standard statistical analyses were utilized. Type I error for all analyses was set at α=0.05.

Methods

Ten cadaveric hips from donors who were a mean (and standard deviation) of 80 ± 9 years old at the time of death were evaluated after posterior soft tissue repair utilizing two different techniques. Five specimens were repaired using no. 2 non-absorbable sutures while five specimens had a repair utilizing braided polyblend suture with a rucking hitch knot technique. Cadaveric specimens were matched based upon age, sex, and laterality. Biomechanical tensile testing using the Instron E10000 Mechanical Testing System and the mechanism of failure were assessed.

Methods

We retrospectively reviewed 2568 aseptic revision THAs completed at our academic institution between 2005 and 2015 through our total joint registry. There were 34% isolated acetabular revisions, 18% isolated femoral revisions, 28% both component revisions, and 20% modular component exchanges. The mean age at index revision THA was 66 years, and 46% were males. The most common indications for the index revision THA were aseptic loosening (21% acetabular, 15% femoral, 5% both components), polyethylene wear and osteolysis (18%), instability (13%), fracture (11%), and other (17%). Mean follow-up was 6 years.

Methods

Patients from two academic institutions undergoing acetabular distraction for chronic pelvic discontinuity were identified between January 2002 and December 2013 with minimum 2-year follow-up. Radiographs at latest follow-up were compared to serial radiographs from the index surgery. Data was collected by chart review in accordance with institutional IRB protocol from both institutions.

Methods

Between May 2010 and July 2016, 32 total hip arthroplasties were performed using a 3-part femoral stem with neck-metaphyseal-stem modular junctions. Surgeries were either the final stage of a two-stage revision for infection, revision THR for loosening, or a revision of a previous non-prosthetic replacement procedure. Patients were entered into an IRB-approved registry and followed with x-rays, HHS, Oxford scores, and patient satisfaction scores. Patients who failed to return for routine follow-up were contacted by phone or email. Two patients had died with their implants intact. Six patients could not be reached for an updated follow-up. One stem was revised for loosening at 33 months due to failed osseointegration in a patient with chronic renal failure. This removed stem was submitted for taper exam and sectioning.

Materials and Methods

Tissues were processed routinely into paraffin sections, stained with H&E and characterized with light microscopic semi-quantitative scores for ALVAL features and for the number of macrophages and lymphocytes, extent of metal debris and the estimated percentage of necrosis per slide. Spearman correlation analysis was conducted to evaluate any correlations between retrieval wear measurements and histological findings.

Background

The Bundled Payments for Care Improvement (BPCI) initiative was introduced to reduce healthcare costs while maintaining quality. We examined data from a healthcare system comprised of five hospitals that elected to participate in the BPCI Major Joint Replacement of the Lower Extremity Model 2 initiative beginning July 1, 2015. We compared one hospital that did 439 BPCI hip cases to the four other hospitals that did 459 cases. Stratifying the data by hospital volume, we sought to determine if costs decreased during the BPCI period, how the savings were achieved, and if savings resulted in financial rewards for participation.

Methods

The Medicare data included the target cost for each episode (based on historical data from 2009–2012 for each hospital that was adjusted quarterly) and actual Part A and Part B spending for 90 days. Using 1,574 primary hip replacements, we analyzed the costs associated with the anchor hospitalization, inpatient rehabilitation, skilled nursing facilities, home health, outpatient physical therapy and readmission to compare the 898 hips done during the 16-month BPCI initiative period with the 676 hips done during the 1-year period preceding BPCI participation. Owing to the nonparametric distribution of the cost data, a Mann-Whitney U test was used to compare the higher volume hospital with the four lower volume hospitals.

Methods

Patients ≥18 years who underwent THA between 2005 and 2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database using procedural codes. Patients with surgical durations >240 minutes were excluded. Patient demographics, operation length, and 30-day major and minor complications were ascertained. Multivariable regression was used to determine if the rate of complications differed depending on length of operation, while adjusting for relevant covariables, and to identify independent predictors of operation length. Covariables of interest included age, sex, American Society of Anaesthesiologists (ASA) class, smoking status, functional status, comorbidities, anesthesia type, and Body Mass Index (BMI).

Methods

The National Surgical Quality Improvement Program database was queried for all primary THAs (CPT code 27130) between 2012 and 2016, yielding 122,451 cases. Cases with reported superficial and/or deep SSIs were combined for an overall rate, and then independently analyzed as deep and superficial SSIs. The infection incidence for each year was calculated. After an overall 5-year correlation and trends, univariate analysis was also performed to compare the most recent year, 2016, with each of the preceding 4 years. Furthermore, a comparison of overall and deep SSI incidences from this study were compared to meta-analysis of pooled data from 2001 to 2011. Pearson correlation coefficients and chi-squared tests were used to determine correlation and statistical significance which was maintained at a p-value less than 0.05.

Methods

Twenty-one cortical bone specimens were from the mid-diaphysis of human donor bone tissue (bilateral femurs from 4 donors: 63M, 61M, 51F, 48F) obtained from the Musculoskeletal Transplant Foundation. Six Raman biomarkers were analyzed: collagen disorganization, type B carbonate substitution (a surrogate for mineral maturation), matrix mineralization, and 3 water compartments. Specimens underwent cyclic fatigue testing under fully reversed conditions at 35 and 45MPa (physiologically relevant stress levels for structural allografts). Specimens were tested to fracture or to 30 million cycles (“run-out”), simulating 15 years of moderate activity (i.e., 6000 steps per day). Multivariate regression analysis was performed using a tobit model (censored linear regression) for prediction of cyclic fatigue life. Specimens were right-censored at 30 million cycles.

Methods

Patients who had a primary THA were identified from the 5% subset of Medicare Parts A/B from 2002–2015. A subgroup with previous CMN for IT hip fracture within the previous 5 years was identified and compared to the remaining THA patients without prior CMN. Length of stay (LOS) was compared using both univariate and multivariate analysis. Infection, dislocation, revision, and readmission were compared between those with and without prior CMN, using multivariate analysis (adjusted for demographic, hospital, and clinical factors).

Methods

Between November 1999 and April 2005, 105 THAs were performed for 90 patients 50 years of age or younger (mean, 42 years; range, 20–50 years). The mean body mass index (BMI) was 30 kg/m2 (range, 17–51 kg/m2). The mean follow-up was 15.25 years (range, 12–19 years). Eight patients (two bilateral) were lost to follow-up, which left 82 patients with 95 hips for analysis. HXLPE was the acetabular bearing for all hips. Harris Hip Scores were collected from all patients. Radiographs were obtained on all patients to evaluate for wear and osteolysis.

Methods

46 prosthetic joint infections underwent irrigation and debridement using 6L of normal saline and 3L of a normal saline and bacitracin mixture prior to the insertion of a new polyethylene liner. This protocol utilized a single equipment setup with all surgical members donning new gloves prior to polyethylene exchange. Between 3 and 5 intraoperative cultures were obtained both prior to and after debridement as per the surgeon's standard protocol. A two-tailed student's t-test was used to evaluate for any differences in the rate of positive culture between these two groups.

Methods

This was an extension of previous work with an updated patient cohort of 5090 consecutive direct anterior primary total hip arthroplasties at a single institution with a single-taper, wedge femoral stem with 4 variants involving length and geometry: Group 1) full length, standard profile; Group 2) full length, reduced distal profile; Group 3) short length, standard profile; and Group 4) short length, reduced distal profile. Records were reviewed retrospectively for the incidence of early periprosthetic fracture or aseptic loosening and analyzed with regard to patient demographics and femoral stem type.

Methods

Serum Co and Cr levels were measured prospectively in 22 patients with a modular dual-mobility construct and a ceramic femoral head. Patients with CoCr heads or contralateral THAs with CoCr heads were excluded. Mean age 64 years with 50% female. The mean follow-up was 4 years. Indications for modular dual-mobility were: periprosthetic joint infection treated with 2-stage exchange and subsequent reimplantation (n=8), ALTR revision (n=7), complex primary THA (n=6), and periprosthetic femoral fracture (n=1). Mean preoperative Co and Cr in patients revised for an ALTR were 29.7 µg/L and 21.5 µg/L, respectively.

Methods

304 Opioid naïve patients undergoing THA or TKA were randomized to receive a prescription for either 30 or 90 5mg oxycodone immediate release (OxyIR) tablets at discharge. All patients received acetaminophen, meloxicam, tramadol and gabapentin perioperatively. Daily opioid consumption, reported in morphine equivalent dose (MED), number of unused OxyIR, and pain scores were calculated for 30 days postoperatively with a patient-completed medication diary. The number of OxyIR refills and total MED received were recorded for 90 days postoperatively. Power analysis determined that 141 patients per group were necessary to detect a 25% reduction in means in opiate consumption between groups. Statistical analysis involved t-test, rank sum, and chi-squared tests with alpha=0.05.

Materials and Methods

This is a retrospective study, using the Truven Health MarketScan database, of anticoagulation medication prescriptions after elective THA, in both commercially insured (CI) and Medicare supplement insured (MS) patients, from 2010 to 2015. After exclusions, there were 83,179 CI and 50,534 MS patients available for analysis. There were 12,876 new users of warfarin (W) and 10,892 new users of rivaroxaban (R) in CI patients, and 7,416 new users of W and 4,739 new users of R in MS patients. We asked the following questions: (1) What were the trends and predictive factors for anticoagulant use after elective THA? (2) What was the actual clinical efficacy: frequency of deep vein thrombosis (DVT) and pulmonary embolism (PE), and frequency of adverse events within 90 days with the two most commonly used oral agents, rivaroxaban and warfarin, from June 2011 to September 2015? Data was analyzed for each anticoagulant by odds ratios using logistic regression models with stabilized inverse probability treatment weighting.

Questions/purposes

The purpose of this study was to assess survivorship, complications and functional outcomes at a minimum 10 years after the constrained tripolar liners used in our institute.

Questions/purposes

The purpose of the present study is to compare the new surgical protocol above to our previously reported early complications in this group of patients

We specifically looked at (1) complications including reoperations; (2) radiologic outcomes; and (3) functional outcomes. Complication rates after (Group 1), and before (Group 2) modified surgical protocol were compared using Chi-square test, assuming statistical significance p<0.05.

Methods

Hip arthroplasty data were extracted from the annual reports from the AJRR and other national registries including: the Australian registry; the New Zealand registry; the United Kingdom, Wales, and Isle of Man registry; the Norwegian registry; and the Swedish registry from 2014 to 2016. Data regarding femoral and acetabular fixation, bearing surface type, femoral head size, the use of dual mobility articulation bearings, hip resurfacing utilization, and THA revision burden were evaluated. Revision burden is defined as the ratio of implant revisions to the total number of arthroplasties performed in a given time period. Registry characteristics and patient demographic data were recorded across all registries. The results were compared between the various registries and reported using descriptive statistics.

Methods

54 primary THA by a single surgeon were reviewed. A new patient questionnaire was administered to document preoperative opioid consumption (type, dosage and length of use); preoperatively and postoperatively POO's measurements [visual analog scale (VAS), QWB-7, SF-36, and WOMAC] and hip scores were recorded. Patients were stratified into two groups: (1) Opioid Users and (2) Non-Opioid Users. Oral morphine equivalents (OME) were calculated for opioid using patients using standard methodology.

Methods

Two head sizes (28 mm, n = 12 and 36 mm, n = 12) and two taper adapter sleeve offsets (small, n = 12 and extra-large, n = 12) were tested in this study. A dynamic impaction rig was constructed to seat the head, sleeve, and stem assembly (Fig. 1). Consistent impaction forces were achieved by dropping a hammer fixed to a lever arm from a pre-determined height onto a standard impactor instrumented with a piezoelectric force sensor (PCB Piezotronics Inc.). Axially applied forces of 2 kN and 6 kN were used to cover a range of typical impaction forces. Three non-contact differential variable reluctance transducers (LORD Sensing Systems) were used to track the displacement of the head relative to the stem. Subsequently, samples were transferred to a servo hydraulic testing machine, and a pull-off test was carried out per ISO 7206–10 to measure the disassembly force.

Methods

A retrospective study of 10,000 joint replacement episodes from a large healthcare system in CJR and a private orthopedic practice in BPCI was conducted. Episodes with costs greater than target price (TP) were designated as bundle busters and sub-divided into 4 groups:

1)

< 1 standard deviation (SD) above TP (n=1700)

Bundle busters were compared to the control that were at/below the TP (n= 7500). For the CJR/BPCI cohorts, one SD was defined as $10,700/$13,000, respectively.

Two linear regressions assessed the likelihood of factors predicting a bundle buster and the total episode cost. These variables included demographics, acuity classifications, comorbidities, length of stay, readmissions, discharge disposition, post-acute utilization, and episode costs.

Methods

Demographic factors and comorbidities were retrospectively reviewed in 863 primary unilateral CJR THAs performed between 2013 and 2017 at a single institution. A predictive model was built from 31 validated comorbidities and a base set of 5 patient factors (age, gender, BMI, ASA, marital status). A multivariable logistic regression model was refined to include only parameters predictive of exceeding the target reimbursement level. These were then assigned weights relative to the weakest parameter in the model.

Materials & Methods

We queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to identify patients who underwent primary THA or TKA between 2010 and 2014. Patients were stratified by procedure and classified as non-obese, obese, or morbidly obese according to BMI. Thirty-day rates of wound complications, deep infection, total complications, and reoperation were compared using univariate and multivariate logistic regression analyses.

Methods

Demographic, cost, and readmission data for 2,605 primary unilateral TJA cases was collected retrospectively and analyzed prior to and after a protocol change where routine closed suction drains and postoperative laboratory tests were eliminated. This protocol change was designed to treat all primary TJA like outpatients regardless of their admission status. Drain usage changed from routine to selective based on hemostasis. Lab studies changed from routine to selective for patients on warfarin for VTE prophylaxis (INR), with ASA 4 or 5 status (BMP), and with a hematocrit < 27% in the recovery room after THA (CBC).

Methods

A canine transcortical model was used to evaluate the performance of three different laser rapid manufacturing (LRM) Ti6Al4V cylindrical implants (5.2 mm diameter, 10mm length): LRM with precipitated hydroxyapatite (P-HA), LRM with plasma sprayed hydroxyapatite (PS-HA), and a hydroxyapatite-free control (No-HA). The implants were 50–60% porous with a mean pore size of 450 μm and have a random interconnected architecture with irregular pore sizes and shapes that are designed based on the structure of cancellous bone. A lateral approach to the femoral diaphysis was used to prepare 5 mm unicortical, perpendicular drill holes in 12 canines. One of each implant type was press-fit into each femur. The femora were harvested at both 4 and 12 weeks post implantation, radiographed and prepared for either mechanical push-out testing to assess the shear strength of the bone-implant interface (left femora, N=6) or for histological processing (right femora, N=6). An un-paired Student's t-test was used to compare statistical significance between the 4 and 12-week results, as well as differences due to implant type; p<0.05 was considered significant.

Methods

PPFFx were identified among all THAs performed at a single academic institution between 1977 and 2015. A training cohort (n = 90 PPFFx) selected randomly by an electronic program was utilized to develop a prototype NLP algorithm and an additional randomly-selected 86 PPFFx were used to further validate the algorithm. Keywords to identify, and subsequently classify, Vancouver type PPFFx about THA were defined. The algorithm was applied to consult and operative notes to evaluate language used by surgeons as a means to predict the correct pathology in the absence of a listed, precise diagnosis (e.g. Vancouver B2). Validation statistics were calculated using manual chart review as the gold standard.

Methods

We used nation-wide linked discharge data from the Hospital Cost and Utilization Project from 2005–2014 to analyze the incidence and recurrence of complications following the first and second stage operations in staged bilateral total hip arthroplasty (BTHAs). Complications included perioperative risks within 30–60 days, and infection and mechanical complications within one year. Conditional probabilities and odds ratios were calculated to determine whether experiencing a complication after the first stage of surgery increased the risk of developing the same complication after the second stage.

Methods

A multi-center cohort from US surgeons in 28 states collected sociodemographic data; medical, emotional, musculoskeletal comorbidities; BMI; and patient-reported pain and function (SF36, HOOS) for elective THR patients. Cases in 2011–2013 were matched with CMS data to ascertain 1 year revision through 2014. Predictors of revision were identified. Chart reviews to verify reasons for revision were performed.

Methods

We conducted a retrospective review of 128 consecutive revision THAs between August 2015 and August 2017, with 62% being referred from another institution. Mean time to revision THA from the index arthroplasty was 10 months. Mean age at revision THA was 61 years, with 67% being female. Three fellowship-trained adult reconstruction surgeons reviewed the radiographs and operative notes and classified the revision THAs into two categories: preventable vs. non-preventable. Reviewers were instructed to be extremely lenient with the benefit of the doubt given to the operative surgeon. Inter-observer reliability was assessed by Cohen's kappa analysis.

Methods

We performed a retrospective review of 3,264 revision THAs (2,645 patients) between 2005–2014, of which 1,142 patients received IV TXA (1g at incision and 1g at closure). The mean age was 65 years with 49% males in the revision group with TXA, and 67 years with 45% males in the revision group treated without TXA. Outcomes analyzed included rates of transfusion and VTE (within 90 days) between cases treated with TXA and cases not treated with TXA. These comparisons were performed for the overall cohort, as well as within the subset of aseptic cases and septic cases. In order to minimize potential bias between these two subgroups, the analyses were weighted with inverse probability of treatment weights based on a propensity score which included age at revision THA, sex, BMI, ASA score, preoperative anticoagulation, and year of surgery. Mean follow-up was 2 years.

Materials & Methods

Clinical scenarios were devised for 5 fictional patients with both symptomatic hip and lumbar spine disorders for which surgical treatment was indicated. An email with survey link was sent to 110 clinical members of the Hip Society and 101 experienced spine surgeons in the USA requesting responses to: which procedure should be performed first, and the rationale for the decision with comments. The clinical scenarios were painful hip osteoarthritis and (1) lumbar spinal stenosis with neurologic claudication; (2) lumbar degenerative spondylolisthesis with leg pain; (3) lumbar disc herniation with leg weakness; (4) lumbar scoliosis with back pain; and (5) thoracolumbar disc herniation with myelopathy. Surgeon choices were compared among scenarios and between surgical specialties using chi-square analysis and comments analyzed using text mining.

Methods

6086 continuous patients undergoing primary THA at a single institution from 2013–2016 were retrospectively evaluated. Data obtained from electronic patient medical records included age, sex, body mass index (BMI), medical comorbidities, surgical approach, and presence of deep PJI. Deep PJI was defined according to National Healthcare Safety Network's (NHSN) criteria for joint space infection following prosthetic hip replacement. Infection rates were calculated yearly for the DA and NA approach groups. Covariates were assessed and used in multivariate analysis to calculate adjusted odds ratios for risk of development of PJI with DA compared to NA approaches. In order to determine the effect of adopting a set of infection prevention protocols and patient optimization on PJI, we calculated odds ratios for PJI comparing patients undergoing THA for two distinct time periods: 2013–2014 and 2015–2016. These periods corresponded to before and after we implemented a set of perioperative infection protocols.

Methods

Relative Value Unit's (RVU's), reimbursement and operative time for 50 PJI procedures were reviewed and compared to 250 primary (1°) THA and 250 primary (1°) TKA by four surgeons. Coding was done per AAOS guidelines.

Materials

Bilateral THA was performed on three fresh frozen cadavers using oversized (jumbo) offset head center revision acetabular cups with an anterior recess (60, 62 and 66 mm diameter) and tapered wedge primary stems through a posterior approach. The relatively large shell sizes were chosen to simulate THA revision cases. At least one fixation screw was used with each shell. A 2mm diameter flexible stainless steel cable was inserted into the psoas tendon sheath between the muscle and the surrounding membrane to identify the location of the psoas muscle radiographically. Following the procedure, CT scans were performed on each cadaver. The CT images were imported in an imaging software for further analysis. The acetabular shells, cables as well as pelvis were segmented to create separate solid models of each. To compare the offset head center shell to a conventional hemispherical shell in the same orientation, the offset head center shell was virtually replaced with an equivalent diameter hemispherical shell by overlaying the outer shell surfaces of both designs and keeping the faces of shells parallel. enabled us to assess the relationship between the conventional shells and the cable. The shortest distance between each shell and cable was measured. To determine the influence of cup inclination and anteversion on psoas impingement, we virtually varied the inclination (30°/40°/50°) and anteversion (10°/20°/30°) angles for both shell designs.

Methods

A total of 864 patients from 17 centers across 8 countries were enrolled into a prospective study. Patients were treated with components from a single manufacturer, which have been shown to be well-functioning in other studies.

Patients completed a battery of PROMs preoperatively, and at one, three, five, and seven years post-THA. Changes in PROMs between study visits were assessed via paired tests.

Postoperative trends for each PROM were determined for each subject by the slope of the best-fit line of the four postoperative data points. Significant PROM deterioration was defined as one literature-defined minimum clinically important difference over 5-years. Binary logistic regressions were used to identify independent predictors of significant decline in the EuroQol (EQ-5D) visual analogue scale (VAS) for Health State, 36-Item Short Form Survey (SF-36) physical composite summary (PCS), and SF-36 mental composite summary (MCS).

Methods

As part of our level one trauma center's institutional hip fracture registry, a retrospective analysis identified 199 intertrochanteric fractures fixed with CMN between 2009 and 2015 with follow up to union or a minimum of three months. The mean follow-up was 22 months (3 to 94 months). Mean patient age was 75 years (50 to 97 years) and 72% were women. Postoperative radiographs were used to measure the TAD, quality of reduction, neck-shaft angle (NSA), and lateral lag screw prominence. Follow-up radiographs were reviewed to assess fracture union, translation, and progression of lateral lag screw prominence. Complications and reoperations were recorded.

Methods

The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2008 to 2016 was queried. Patients were identified using the Current Procedural Terminology (CPT) code for THA (27130) and divided into groups by diagnosis; OA in one group and FNF in another. Univariate statistics were performed. T-test compared continuous variables between groups, and Chi-square test compared categorical variables. Multivariate and propensity matched logistic regression analyses were performed to control for risk factors of interest. The primary outcomes for this study were death or serious morbidity (surgical site infection (SSI), infection, respiratory complication, cardiac complication, sepsis, or blood loss anemia requiring postoperative transfusion). Additional secondary outcomes included the incidence of specific complications, total operative time (time from incision to closure), length of hospital stay and proportion of patients that were discharged home.

Methods

This was a prospective cohort study. Patients completed the PHQ-2 and the Hip Disability and Osteoarthritis Outcome Score - Joint Replacement (HOOS-JR) prior to THA, with follow-up at 6 weeks and 6 months. An a priori power analysis determined a sample size of 31 would detect an effect size of 0.5 with a power of 0.80. We used previously established minimum clinically important difference (MCID) values for HOOS-JR. Continuous variables were analyzed with t-tests or Mann-Whitney tests while categorical variables were analyzed with Chi square or Fisher exact tests.

Methods

In a cluster-randomized, crossover trial, 235 patients undergoing THR were assigned to receive multimodal analgesia with minimal opiates (Group A-10 tablets), multimodal analgesia with a full opiate supply (Group B-60 tablets), or a traditional opiate regimen without multimodal analgesia (Group C-60 tablets). The multimodal regimen comprised scheduled-dose acetaminophen, meloxicam, and gabapentin. Primary outcomes were daily pain and opiate utilization for the first 30-days. Secondary outcomes included assessments of satisfaction, sleep-quality, opiate-related symptoms, hip function, and adverse events.

Methods

We reviewed 96 CFAC cases performed in 91 patients between 2004 and 2017, from which 36 variables were collected spanning patient demographics, pre-operative clinical and radiographic features, intraoperative information, and implant design characteristics. Patient demographics and relevant clinical features were collected from individual medical records. Radiographic review included analysis of pre-operative radiographs, computer tomographic (CT) scans, and serial post-operative radiographs. Radiographic failure was defined as loosening or gross migration as determined by a board-certified orthopedic surgeon. CFAC implant design characteristics and intra-operative features were collected from the design record, surgical record and post-operative radiograph for each case respectively.

Two sets of statistical analyses were performed with this dataset. First, univariate analyses were performed for each variable, comprising of a Pearson chi-square test for categorical variables and an independent t-test for continuous variables. Second, a random forest supervised machine learning method was applied to identify the most influential variables within the dataset, which were then used to perform a bivariable logistic regression to generate odds ratios. Statistical significance for this study was set at p < 0.05.

Methods

We performed a retrospective review of concurrent HS/PAO cases in a prospectively collected institutional hip preservation database. From November 2005 to December 2012, 85 hips in 80 patients underwent combined HS/PAO. Two hips had a diagnosis other than acetabular dysplasia and 12 hips were lost to follow up, leaving 71 hips for analysis at mean 6.6-year follow-up (range 4–11 years). Hips were evaluated using the University of California, Los Angeles (UCLA) Activity Score, modified Harris Hip Score (mHHS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscore. Hips were stratified into preserved or failed groups, with failure defined as conversion to THA or a symptomatic hip (mHHS <70 or WOMAC pain subscore > 10). Complications were recorded and graded by the Clavien-Dindo classification. Regression analyses were performed to identify the interaction between patient factors, radiographic measures, and surgical details with outcome.

Methods

All patients were assessed jointly by a paediatric hip surgeon and an adult hip arthroplasty surgeon pre-operatively, with all procedures conducted at a dedicated tertiary care paediatric centre under general anesthesia. All procedures were completed through a direct lateral (trans-gluteal) approach, using uncemented components (Zimmer Biomet®, Warsaw, IN) and a ceramic on highly cross-linked polyethylene bearing. Data was collected prospectively after approval from the Institutional Review Board. All patients completed clinical examination and functional scores pre-operatively and at six months post-operatively.

Methods

We retrospectively compared the radiographic pelvic ratio among 90 patients undergoing THA. AP radiographs were obtained in the standing position preoperatively and at 6 weeks after surgery; in the lateral decubitus position after trial reduction intraoperatively; and in the supine position in the post anesthesia care unit (PACU). Pelvic ratio was defined as the ratio between the vertical distance from the inferior sacroiliac (SI) joints to the superior pubic symphysis and the horizontal distance between the inferior SI joints. Radlink software was used to determine the pelvic ratio on each radiograph. Changes in apparent cup position based on changes in pelvic ratio were calculated using data from the literature, and a change of at least 10 degrees in acetabular component position was defined as clinically meaningful. Analyses were performed using paired t-tests, with p<0.05 defined as significant.

Methods

From Jan 1 2009 to Dec 31 2013, 525 primary THAs were performed by the author. After the components were implanted, the greater trochanteric bursa was removed, and the gluteus medius and minimus attachments to the greater trochanter were visualized and palpated. Ninety-five hips (95 patients) were found to have damaged muscle attachments to bone. Fifty-four hips had mild damage consisting of splits in the tendon, but no frank avulsion of abductor tendon from the bone attachment. None had severe atrophy of the abductor muscles, but all had partial fatty infiltration. All hips with this mild lesion had repair of the tendons with #5 Ticron sutures to repair the tendon bundles together, anchored to the greater trochanter. Forty-one hips had severe damage with complete or nearly complete avulsion of the gluteus medius and minimus muscles from their attachments to the greater trochanter. Thirty-five of these hips had partial fatty infiltration of the abductor muscles, but all responded to electrical stimulation. The surface of the greater trochanter was denuded of soft tissue with a rongeur, the muscles were repaired with five-seven #5 Ticron mattress sutures passed through drill holes in the greater trochanter, and a gluteus maximus flap was transferred to the posterior third of the greater trochanter and sutured under the vastus lateralis. Six hips had complete detachment of the gluteus medius and minimus muscles, severe atrophy of the muscles, and poor response of the muscles to electrical stimulation. The gluteus medius and minimus muscles were sutured to the greater trochanter, and the gluteus maximus flap was transferred. Postoperatively, patients were instructed to protect the hip for 8 weeks, then abductor exercises were started.

Methods

Patients were selected from a clinical registry at an urban tertiary academic medical center. All patients undergoing primary THA between January 1, 2000 and April 1, 2016 were eligible for this study. During this period, patients were asked to complete the Harris Hip Score (HHS), Euro-QoL 5 Dimension (EQ-5D), 0–10 Numerical Rating Scale (NRS) Pain, 0–10 NRS Satisfaction (only given postoperatively), the Charnley Classifier, and the University of California Los Angeles (UCLA) Activity Score.

To determine SES, patients were matched by zip code to corresponding median household income as reported by the United States Census Bureau. Patients were then dichotomized into low and high SES groups using 2016 median household income of $57,617 USD as a cutoff point.

Statistical differences between low and high SES patients were determined for demographic factors, preoperative PROMs, postoperative PROMs, and PROM change. Non-parametric variables were tested with the Mann Whitney U test and categorical variables were tested with the Chi squared test.

Multivariate models were created to determine if SES group was independently predictive of achieving a minimal clinically important improvement (MCII) in PROMs (18.0 for HHS, −2.0 for NRS Pain, and 0.92 for UCLA). As potential confounders, we tested body mass index (BMI), preoperative health state from EQ-5D visual analog scale (EQ VAS), age at surgery, preoperative Charnley class, sex, and time between PROMs.

Methods

Over the last 10 years, a systematic search of the US national library of Medicine and National institutes of health with the key words “metal-on-metal” and hip resurfacing” was conducted and returned 2186 items. Of these items, 862 were deemed relevant to our research purposes and entered in our center's reference database from which this review was performed.

Methods

The Limited Data Set (LDS) from the Centers for Medicare and Medicaid (CMS) were used for this study. All elective, DRG 470 Total Hip Arthroplasties (THA) reported by CMS from the first quarter of 2013 through the second quarter of 2016 were included. Volume and part A Medicare payments over a 90-day period for the 20 highest volume hospitals in the US were analyzed. Cost associated with initial hospital stay and post discharge skilled nursing, home health, long term acute care, inpatient rehabilitation facilities, and readmission was aggregated and analyzed. For each episode, demographic information (age, sex, and race), geographic location, and Elixhauser comorbidities were calculated to control for major confounding factors in the regression.

Methods

We constructed a state-transition Markov model to compare the cost-utility of THA and NM in the six above-mentioned BMI groups over a 15-year time period. Model parameters for transition probability (i.e. risk of revision, re-revision, death), utility, and costs (inflation adjusted to 2017 US dollars) were estimated from the literature. Direct medical costs of managing hip arthritis were accounted in the model. Indirect societal costs were not included. A 3% annual discount rate was used for costs and utilities. The primary outcome was the incremental cost-effectiveness ratio (ICER) of THA versus NM. One-way and Monte Carlo probabilistic sensitivity analysis of the model parameters were performed to determine the robustness of the model.

Methods

An a priori power analysis determined 123 participants per group were needed to detect a relative difference of 20% among groups with 80% power. After IRB approval, patients were screened; included patients met American College of Rheumatology classification criteria. Patients were approached between April 2017 and May 2018 and asked to perform a nasal swab while on site using the Center for Disease Control's swabbing protocol; questionnaires pertaining to their current health status were collected. Swabs were inoculated onto ChromAgar/ChromID MRSA plates for detection of S. aureus. Mann-Whitney U and Chi-square tests were used to evaluate baseline differences between groups. Logistic regression evaluated the associations between groups and S. aureus carriage. All statistical analyses were performed using SAS Software version 9.3 (SAS Institute, Cary, NC); statistical significance was defined as p<0.05.