Introduction

Patients undergoing primary total hip arthroplasty (THA) following pelvic radiation have historically had poor survivorship free of aseptic acetabular component loosening. However, several series have reported improved results with tantalum acetabular components. The purpose of this study was to assess implant survivorship, radiographic results, and clinical outcomes of contemporary, non-tantalum, porous acetabular components in the setting of prior pelvic radiation.

Methods

We retrospectively reviewed 33 patients (38 hips) with prior therapeutic pelvic radiation between 2006 and 2016 who underwent primary THA. The mean overall pelvic radiation dose was 6300 cGy with a mean latency period to THA of 5 years. The most common acetabular component was Pinnacle (Depuy-Synthes) in 76%, followed by Trident (Stryker) in 8%, Tritanium (Stryker) in 8%, Trilogy (Zimmer-Biomet) in 5%, and G7 (Zimmer-Biomet) in 3%. Eighty-seven percent of cups were fixed with screws, of which the mean number used was 3. The mean age at primary THA was 74 years, 76% were male, and the mean BMI was 30 kg/m². Mean follow-up was 5 years.

Introduction

Survival after contemporary solid organ transplant (SOT) is increasing, and demand for total hip arthroplasty (THA) among SOT recipients is rising accordingly. The purpose of this study is to compare the perioperative outcomes and short-term implant- and patient-survivorship of contemporary THA following the most common types of SOT.

Methods

Among SOT recipients, 119 primary THAs (92 patients, 39% female) were performed at a single institution from 2000–2020 and were retrospectively reviewed at a mean follow-up of 3.6yrs. Revisions, conversion to THA and multiple organs transplanted were excluded. The most common SOT was renal (39%), followed by lung (34%), liver (18%) and heart (8%). Demographics, peri-operative outcomes, 90-day re-admissions, re-operations and mortality were compared between SOT groups using chi-squared, Fisher's exact, Wilcoxon tests and Cox proportional hazard ratios.

Introduction

A staging system has been developed to revise the 1994 ARCO classification for ONFH. The final consensus resulted in the following 4-staged system: stage I—X-ray is normal, but either magnetic resonance imaging or bone scan is positive; stage II—X-ray is abnormal (subtle signs of osteosclerosis, focal osteoporosis, or cystic change in the femoral head) but without any evidence of subchondral fracture, fracture in the necrotic portion, or flattening of the femoral head; stage III—fracture in the subchondral or necrotic zone as seen on X-ray or computed tomography scans. This stage is further divided into stage IIIA (early, femoral head depression ≤2 mm) and stage IIIB (late, femoral head depression >2 mm); and stage IV—X-ray evidence of osteoarthritis with accompanying joint space narrowing, acetabular changes, and/or joint destruction. Radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) scans may all be involved in diagnosing ONFH; however, the optimal diagnostic modality remains unclear. The purpose of this study was to identify: 1) how ONFH is diagnosed at a single academic medical center, and 2) if CT is a necessary modality for diagnosing/staging OFNH.

Methods

The EMR was queried for the diagnosis of ONFH between 1/1/2008–12/31/2018 at a single academic medical center. CT and MRI scans were reviewed by the senior author and other contributors. The timing and staging quality of the diagnosis of ONFH were compared between MRI and CT to determine if CT was a necessary component of the ONFH work-up.

Introduction

In early stage osteonecrosis of the femoral head (ONFH), core decompression (CD) is often performed; however, approximately 30% of CD cases progress to femoral head collapse. Bone healing can be augmented by preconditioning MSCs (pMSCs) with inflammatory cytokines. Another immunomodulatory approach is the timely resolution of inflammation using cytokines such as IL-4. We investigated the efficacy of pMSC and genetically modified MSCs that over-express IL-4 (IL4-MSCs) on steroid-associated ONFH in rabbits.

Methods

Thirty-six male skeletally mature NZW rabbits received methylprednisolone acetate (20mg/kg) IM once 4 weeks before surgery. There were 6 groups:

CD alone – a 3 mm drill hole

+ injection into the CD of:

Eight weeks after surgery, femurs were harvested, and evaluated by microCT, biomechanical, and histological analyses.

Introduction

The long-term survival of modern ceramic-ceramic bearings in young active patients with osteonecrosis undergoing total hip arthroplasty (THA) is unknown. A previously published study of this series at 5-year follow-up demonstrated an extremely high activity level. The purpose of this study is to examine whether this very high activity level is associated with ceramic-on-ceramic THA failure at long-term follow-up.

Methods

This is a retrospective review of a single-surgeon at an academic medical center between years 2003–2010. Inclusion criteria were consecutive series of ceramic-on-ceramic articulations in patients younger than 50 with a diagnosis of osteonecrosis. Median follow-up was 12.4 years (range 10–17). Data was collected via mail, telephone, and e-mail surveys. Exclusion criteria included deceased prior to follow-up. Preoperative and postoperative Western Ontario and McMaster University Arthritis Index (WOMAC) and University of California at Los Angeles Activity scores (UCLA) were collected. Student t-tests were used as appropriate.

Introduction

Instability remains a common complication following total hip arthroplasty (THA) and continues to account for the highest percentage of revisions in numerous registries. Many risk factors have been described, yet a patient-specific risk assessment tool remains elusive. The purpose of this study was to apply a machine learning algorithm to develop a patient-specific risk score capable of dynamic adjustment based on operative decisions.

Methods

22,086 THA performed between 1998–2018 were evaluated. 632 THA sustained a postoperative dislocation (2.9%). Patients were robustly characterized based on non-modifiable factors: demographics, THA indication, spinal disease, spine surgery, neurologic disease, connective tissue disease; and modifiable operative decisions: surgical approach, femoral head size, acetabular liner (standard/elevated/constrained/dual-mobility). Models were built with a binary outcome (event/no event) at 1-year and 5-year postoperatively. Inverse Probability Censoring Weighting accounted for censoring bias. An ensemble algorithm was created that included Generalized Linear Model, Generalized Additive Model, Lasso Penalized Regression, Kernel-Based Support Vector Machines, Random Forest and Optimized Gradient Boosting Machine. Convex combination of weights minimized the negative binomial log-likelihood loss function. Ten-fold cross-validation accounted for the rarity of dislocation events.

Background

Dislocation is a common complication following total hip arthroplasty (THA), and accounts for a high percentage of subsequent revisions. The purpose of this study was to develop a convolutional neural network (CNN) model to identify patients at high risk for dislocation based on postoperative anteroposterior (AP) pelvis radiographs.

Methods

We retrospectively evaluated radiographs for a cohort of 13,970 primary THAs with 374 dislocations over 5 years of follow-up. Overall, 1,490 radiographs from dislocated and 91,094 from non-dislocated THAs were included in the analysis. A CNN object detection model (YOLO-V3) was trained to crop the images by centering on the femoral head. A ResNet18 classifier was trained to predict subsequent hip dislocation from the cropped imaging. The ResNet18 classifier was initialized with ImageNet weights and trained using FastAI (V1.0) running on PyTorch. The training was run for 15 epochs using ten-fold cross validation, data oversampling and augmentation.

Background

The use of the direct anterior approach (DAA) for total hip arthroplasty (THA) has increased in recent years. This is in part due to the proposed benefits of a faster early recovery and a lower risk of dislocation. The purpose of this study is to understand the dislocation rate in a non-selective, consecutive cohort of patients undergoing THA via the DAA including those at high risk for instability due to spinopelvic pathology.

Methods

We performed a retrospective review of a large prospectively collected single institution database assessing all patients undergoing THA via the DAA between 2011 and 2017. The primary outcome measure was dislocation at minimum two-year follow-up. We then stratified patients by known risk factors for dislocation including spinopelvic pathology and performed an in-depth analysis of those patients who had a dislocation event.

Purpose

Patients with acetabular dysplasia demonstrate altered biomechanics during gate and other activities. We hypothesized that these patients exhibit a compensatory increase in the anterior pelvic tilt during gait.

Materials & Methods

Twelve patients were included in this prospective radiographic and gait analysis study prior to the PAO. All were women. The mean age was 27 years (+/− 8 yrs). Tonnis grade was zero in nine, and one in three hips. All patients performed multiple one-minute walking trials on the level, the incline, and the decline treadmill surfaces in an optical motion capture lab. Anterior pelvic tilt is reported in (+), while the posterior pelvic tilt is reported in (–) values.

Introduction

Spinopelvic mobility has been associated with THA outcome. To-date spine assessments have been made quasi-statically, using radiographs, in standing and seated positions but dynamic spinopelvic mobility has not been well explored. This study aims to determine the association between dynamic (motion analysis) and quasi-static (radiographic) sagittal assessments and examine the association between axial and sagittal spinal kinematics in hip OA patients and controls.

Methods

This is a prospective, IRB approved, cohort study of 12 patients with hip OA pre-THA (6F/6M, 67±10 years) and six healthy controls (3F/3M, 46±18 years). All underwent lateral spinopelvic radiographs in standing and seated bend-and-reach (SBR) positions. Pelvic tilt (PT), pelvic-femoral-angle (PFA) and lumbar lordosis (LL) angles were measured in both positions and the differences (Δ) in angles between SBR and standing were computed. All participants performed two dynamic tasks at the motion laboratory: seated maximal trunk rotation (STR) and seated bend and reach (SBR). Three-dimensional joint motion data were collected and processed by a 10-camera infrared motion analysis system (Vicon, Nexus 2.10, UK). Total axial and sagittal spine (mid-thoracic to lumbar) range of motion (ROM) were calculated for STR and SBR, respectively.

Introduction

Cross table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). CTL measurements may differ by >10 degrees from CT scan measurements, but the reasons for this discrepancy are poorly understood. We compare anteversion measurements made on CTL radiographs and CT scans to identify spinopelvic parameters predictive of inaccuracy.

Methods

THA patients (n=47) with preoperative spinopelvic radiographic analysis and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on post-operative CTL radiographs, and CT scans using 3D reconstructions of the pelvis. Patients were grouped by error (CTL-CT)>10° (n=11) or <10° (n=36), and spinopelvic mobility parameters were compared using t-tests. Correlation between error and mobility parameters was assessed with Pearson coefficient.

Introduction

The prevalence of the various patterns of spinopelvic abnormalities that increase the risk for prosthetic impingement is unknown. While prior surgery or lumbar fusion are recognized as a risk factors for postoperative dislocation, many patients presenting for THA do not have obvious radiographic abnormalities. The purpose of this study is to determine the prevalence of large posterior pelvic tilt (PPT) when standing, stiff lumbar-spine (SLL) and spino-pelvic sagittal imbalance (SSI) in patients undergoing primary THA.

Methods

A consecutive series of 1592 patients (56% female) over 2 years underwent functional analysis of spinopelvic mobility using CT, standing, and flexed seated lateral radiographs as part of pre-operative THA planning. The average age was 65 (20–93). We investigated the prevalence of these 3 validated spinopelvic parameters known to increase the risk for impingent and correlated them to the patient's age and gender using Chi squared analysis. Finally, the risk of flexion and extension impingement was modeled for each patient at a default supine cup orientation (DSCO) of 40°/20° (±5°).

Introduction

The effect of spine-pelvis position and motion on hip arthroplasty function has been increasingly appreciated in the past several years. Some authors have stressed the importance of using precision technologies for component placement while others have advocated the use of dual mobility articulations or large bearings and lateralized liners in patients with fused lumbar spines. The current study assesses the prevalence of stiff and fused spines in an elective total hip arthroplasty population.

Methods

One hundred and forty-nine patients undergoing elective total hip arthroplasty were assessed preoperatively with CT (computed tomography) and functional radiographs for the purpose of CT based planning and intraoperative navigation of total hip arthroplasty (HipXpert System, Surgical Planning Associates, Inc., Boston, MA). The functional radiographs included standing and sitting lateral images (EOS Imaging, SA, Paris, France). Patients were assessed for supine, standing and sitting pelvic tilt (PT) and change in sacral slope (SS). Spine stiffness was defined by a change in sacral slope (SS) of less than or equal to 10 degrees on the standing to sitting lateral radiographs according to Luthringer et al JOA 2019.

Introduction

Periacetabular osteotomy (PAO) is the preferred treatment for symptomatic acetabular dysplasia in adolescents and young adults. There remains a lack of consensus regarding whether intra-articular work such as labral repair or improvement of femoral offset should be performed at the time of PAO or addressed subsequent to PAO if symptoms warrant. The purpose of this review was to determine the rate of subsequent hip arthroscopy (HA) in a contemporary PAO cohort with no intra-articular work performed at the time of PAO.

Methods

From June 2012 to September 2019, 272 Rectus Sparing PAOs were performed and followed for a minimum of one year (mean 4.6 years). The average age was 24 (range 14–44) and 87% were female. The average BMI was 25 and average length of hospital stay was 2.9 days. Patients were evaluated at last follow-up with PROMIS PF-CAT, pain and mental health scores. Clinical records were reviewed for complications or subsequent surgery. Pre and post-operative radiographs were reviewed for change in the following acetabular parameters: LCEA, ACEA, AI, and the alpha-angle was obtained from preoperative radiographs. Patients were cross-referenced from the two largest hospital systems in our area to determine if subsequent HA was performed. Descriptive statistics and logistic regression were used to analyze risk factors for HA.

Background

The impact of a patient's activity level following total hip arthroplasty (THA) remains controversial, with some concerned about increased polyethylene wear, aseptic loosening and revisions. The purpose of this study is to report on implant survivorship and outcomes of high activity patients compared to low activity patients after THA with current polyethylene.

Methods

A retrospective review identified 2002 patients (2532 hip) that underwent a primary THA with vitamin E infused highly crosslinked polyethylene liner and 2-year minimum follow-up or revision. Patients were divided in two groups based on their University of California Los Angeles (UCLA) activity level: Low activity (LA) (UCLA ≤5) and high activity (HA) (UCLA ≥ 6). Outcomes included Harris Hip Score, UCLA activity score, complications and reoperations. Multivariate nominal regression analysis was performed to evaluate the significance of postoperative activity level on survivorship while controlling for age, gender, preoperative pain, HHS and body mass index (BMI).

Introduction

Modular dual mobility (MDM) prostheses are increasingly utilized for total hip arthroplasty (THA) to mitigate the risk of postoperative instability in high risk patients. Short-term reports on clinical outcomes are favorable but there are few studies on young active patients. This study quantified proximal femoral stress shielding and metal ion release in MDM combined with modern cementless stem design in young active patients.

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. DEXA scans were performed at 6 weeks postoperatively as a baseline, then again at 6 months, 1 year, 2 years and 5 years postoperatively as were metal ions.

Introduction

THA for patient's 50 years and younger is a procedure at high risk for complications and failure because of the high level of activity of this population. Highly cross linked polyethylene (HXLPE) has greatly improved the durability of the implant because of the improved wear characteristics. Few studies have followed this population into the second decade and therefore the purpose of this investigation was to evaluate the clinical outcome for the patients 5o years of age and younger at a minimum of 15 years. The second purpose was to evaluate the radiographic findings secondary to wear or mechanical failure of the implant.

Methods

Between October 1999 and December 2005, 105 THAs were performed in 95 patients (53 female, 42 male) age 50 years and younger (mean 42 years; range 20–50). Ten patients (10 hips) were lost to follow-up or deceased. The remaining 95 hips and 85 patients were followed for a minimum of 15 years (mean of 16.8, range 15–20.5) for analysis. HXLPE (Longevity, Zimmer Biomet) was the acetabular bearing for all hips. Radiographs were evaluated for radiolucent lines and osteolysis.

Introduction

The BIRMINGHAM HIP^◊ Resurfacing is a metal-on-metal (MOM) hip implant system approved by the US FDA in 2006. The approval required a multicenter, prospective, post-approval study (PAS). Our purpose is to report the current minimum 10-year results.

Methods

253 patients (280 hips) had surgery between October 2006 and December 2009 at one of 5 sites. We report revisions, survivorship, EQ-5D, Harris Hip Score (HHS), radiographic findings, and metal levels including cobalt (Co) and chromium (Cr). The mean age at surgery was 51 years, 74% male, BMI 28, osteoarthritis 95%. 243 (87%) of hips have known outcome or 10-year minimum follow-up (fup). Prior to 10 years, 5 patients died, 20 hips were revised, and 37 hips did not complete 10-year fup.

Background

Hip resurfacing arthoplasty (HRA) showed promising early and mid-terms results at the beginning of the new millennium. Adverse local tissue reactions associated with metal debris considerably slowed down the implantation of HRA which use is now limited to a few specialized centers. The long term success of this procedure, however, is still largely unknown. This study aimed to provide the clinical results of a series of 400 consecutive HRA with a minimum follow-up of 20 years.

Methods

All patients treated with Conserve^®Plus HRA between November 1996 and November 2000 were retrospectively selected and 355 patients (400 hips) were included. The clinical results of this series was previously reported in 2004 at a follow up of 2 to 6 years[1]. There were 96 women (27%) and 259 men (73%). Mean age at surgery was 48.2 ± 10.9 years. Long-term survivorship was assessed with Kaplan-Meier survival estimates. UCLA hip scores and SF-12 quality of life scores were collected at follow-up visits. Radiographic positioning of the acetabular component was assessed with the computation of the contact patch to rim (CPR) distance. Radiolucencies about the metaphyseal stem and around the acetabular component were recorded to assess the quality of the component fixation.

Introduction

While additional resources associated with direct anterior (DA) approach total hip arthroplasty (THA) such as fluoroscopy, staff, and special tables are well recognized, time consumption is not well studied. The purpose of this study was to analyze anesthesia and surgical time in DA and posterior approach THA in a large healthcare system across multiple facilities and surgeons.

Methods

3,155 unilateral primary THAs performed via DA or posterior approaches between 1/1/2017 and 06/30/2019 at nine hospitals and ambulatory surgery centers (ASC) in a large metropolitan healthcare system were retrospectively reviewed. All surgeons were experienced and beyond learning curves. 247 cases were excluded to eliminate confounds. Operating room (OR) in and out times and surgical times were collected via EMR electronic and manual data extraction with verification. Multivariate statistical analyses were utilized with p<0.05 significant.

Introduction

The direct anterior approach (DAA) for total hip arthroplasty (THA) has gained popularity in recent years. Potential advantages over other surgical approaches include less postoperative pain, fewer postoperative precautions, and quicker early recovery. It is most commonly performed in the supine position with traction tables or table mounted bone hooks to facilitate exposure. In this study, we describe a reproducible surgical technique for DAA THA in the lateral decubitus position with use of standard THA equipment and report on our results and learning curve.

Methods

A prospectively collected hip repository was queried for all primary THA DAA performed in the lateral position by a single surgeon over a 4-year period from the surgeon's first case utilizing the technique. Retrospective chart review was performed to identify complications and revisions. Modified Harris Hip Score (mHHS) was collected pre-operatively and again at 1-year post-operative. Radiographic parameters including were measured on the 1-year postoperative radiographs.

Introduction

Cemented femoral fixation has been shown to carry a lower risk of peri-prosthetic fracture (PPF). The aim of this study was to determine whether adequate (1) stem position and (2) cement mantle (i.e. factors associated with outcome of cemented stems) can be achieved with the anterior approach as compared to the posterior approach.

Methods

This is a prospective, multi-surgeon, single center, consecutive, case-matched series. Twenty patients/hips (age: 76±SD 14) that underwent cemented fixation of their femoral component via an anterior approach (AA) were matched with twenty hips that received the same cemented femoral components via the posterior approach by the same surgeons. Outcome measures of interest included Barrack classification (A, B, C or D), Coronal alignment defined as Varus (>5º), mild varus (3–5º), neutral, mild valgus (3–5º) and valgus (>5º) of the stem and sagittal component alignment defined as anterior to posterior, neutral, posterior to anterior (±3 degrees) and cement mantle thickness in all Gruen zones.

Background

The acknowledged benefit of the direct anterior (DA) approach is early functional return. Most surgeons in the U.S. use cementless femoral replacement given the negative track record of some cemented designs. However, delayed osseointegration of a femoral stem typically seen in older patients with poor bone quality will delay recovery, diminishing the benefits of the DA approach. Registry studies have shown a higher revision rate and complications in this patient population leading to a renewed interest in cemented fixation.

Questions posed

To achieve the functional benefits of the DA approach and the fixation benefits of cemented replacement, this study combined the 2 techniques posing the following questions:1) Does the limited access of the DA approach adversely affect the cement technique? 2) Does such a cementing technique reduce the incidence of cementless complications?

Introduction

The rise of the anterior approach (AA) in primary surgery has led to enthusiasm for using this approach in revision surgery, especially because head and liner exchanges have been accompanied by a high dislocation rate when the posterior approach (PA) is used. The aim of this study was to compare the institutional dislocation rate comparing the PA and AA in isolated head and liner exchange.

Methods

A retrospective institutional database query was done to identify all aseptic head and liner exchanges between the years 2010- June, 2020. 186 hips were identified with an average age of 64.8+/−10.8 yrs (27.9–87.6) and average BMI of 28.7+/−6.3 kg/m2 (16.2–52). The reason for revision was polyethylene wear and osteolysis in 105 hips (56.5%), adverse tissue reaction to metal on metal (MOM) in 43 hips (23.1%), and recurrent instability in 38 hips (20.4%). The approach used for the revision surgery was PA in 128 hips (68.8%) and AA in 58 hips (31.2%). The mean follow-up for this cohort is 1.9±2 yrs (0.0–8.6).

Introduction

With resumption of non-urgent surgery in May 2020, standard anesthesia for hip arthroscopy switched from general with endotracheal intubation (GA) to spinal (SA) in response to COVID-19 implications; reducing potential aerosolized exposure for patient and staff and reducing consumption of personal protective equipment (PPE). There are no studies that compare the attributes for these two anesthesia methods for hip arthroscopy; and thus, this was viewed as an opportunity to perform a comparative observational study on SA to a recent matched group of GA.

Methods

Beginning in May 2020, SA became the standard for hip arthroscopy. GA was used if the patient refused SA or had a history of previous lumbar spinal surgery, or body mass index (BMI) greater than 35. SA patients were carefully matched for age, gender and procedure to a recent previous GA population and compared for recovery room (RR) length of stay, entry and discharge visual analog scores (VAS), morphine mg equivalent (MME) usage, and untoward events. Additionally, SA and GA cases performed since May 2020 were compared for the length of time from entry to the operating room (OR) until the surgeon was able to perform an examination under anesthesia (EUA).

Introduction

Early ambulation after total hip arthroplasty (THA) predicts early discharge. Spinal anesthesia is preferred but can delay ambulation, especially with bupivacaine. Mepivacaine, an intermediate-acting local anesthetic, could enable earlier ambulation than bupivacaine. We hypothesized that patients who received mepivacaine would ambulate earlier than those who received hyperbaric bupivacaine or isobaric bupivacaine for primary THA.

Methods

This was a randomized, double-blind controlled trial of patients undergoing primary THA. Patients were randomized 1:1:1 to mepivacaine 52.5 mg, hyperbaric bupivacaine 11.25 mg, or isobaric bupivacaine 12.5 mg for spinal anesthesia. The primary outcome measure was ambulation between 3–3.5 hours. Secondary outcomes included return of motor and sensory function, postoperative pain, opioid consumption, urinary retention, transient neurological symptoms, intraoperative muscle tension, length of stay and 30-day readmissions. A priori power analysis required 44 patients per group. After testing for normality (Shapiro-Wilk test), continuous data were analyzed using analysis of variance (ANOVA) or Kruskal-Wallis, as appropriate, and categorical data were analyzed with chi square.

Introduction

With the widespread legalization of cannabis across the United States, well-powered studies evaluating the impact of cannabis use disorder on outcomes following primary total hip arthroplasty are warranted. Therefore, the aim of this study was to determine whether cannabis use disorder has an effect on patients who undergo primary hip arthroplasty in terms of: 1) hospital lengths of stay (LOS); 2) medical complications; 3) implant-related complications; and 4) costs of care.

Methods

Using an administrative database, patients who underwent primary total hip arthroplasty and had cannabis use disorder were matched to a cohort who did not in a 1:5 ratio by age, sex, and various medical comorbidities. This yielded 44,154 patients; 7,361 who had cannabis use disorder and 36,793 who did not. Variables for analysis included postoperative LOS, 90-day medical complications, 2-year implant-related complications, and 90-day costs of care. Mann-Whitney-U tests were used to compare LOS and costs. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of developing complications. A p-value less than 0.005 was considered statistically significant.

Introduction

Prosthetic designs that use porous metals possess an extremely high surface area and through capillary effect may potentially ‘absorb’ and later elute analgesic solution, serving as a surgical site drug depot. This study aimed to determine if a highly porous acetabular component submerged in an aqueous-based analgesic solution prior to implantation reduced postoperative pain scores and opioid consumption in the early post-operative period.

Methods

Using our IRB approved database, 200 consecutive opioid naïve primary THA patients operated on by a single surgeon at two institutions using the same acetabular component were identified. 100 patients had a standard volume/concentration of an analgesic cocktail soft-tissue injection at closure (control). 100 patients had their acetabular components submerged into the same cocktail prior to implantation (treatment) and the balance of the volume injected. Postoperative protocols were otherwise identical. Groups were compared for visual analog pain scores (VAS), opioid consumption, 1-year radiographic findings and surgical revision rates.

Introduction

Due to the opioid epidemic, our service developed a cultural change highlighted by decreasing discharge opioids after lower extremity arthroplasty. However, concern of potentially increasing refill requests exists. As such, the goal of this study was to analyze whether decreased discharge opioids led to increased postoperative opioid refills.

Methods

We retrospectively reviewed 19,428 patients undergoing a primary hip or knee arthroplasty at a single institution from 2016–2019. Patients that underwent secondary procedures within that timeframe were excluded. Two-thousand two-hundred and forty-one patients (12%) were on narcotics preoperatively or had chronic pain syndrome. Two reductions in routine discharge narcotics were performed over this timeframe. First, 8,898 patients routinely received 750 morphine milligram equivalents (MMEs). After the first reduction, 4,842 patients routinely received 520 MMEs. After a second reduction, 5,688 patients routinely received 320 MMEs. We analyzed refill rates, refill MMEs, and whether discharge MMEs were associated with refill MMEs in a multivariate model.

Introduction

Wound complications following revision total hip arthroplasty (THA) are associated with an increased risk of superficial and deep infections. Closed incision negative-pressure therapy (ciNPT) has been reported to decrease this risk. This study's purpose was to assess if ciNPT decreases the rate of wound complications following revision THA versus a conventional, silver-impregnated dressing.

Methods

This was a single center, randomized controlled trial of patients undergoing both septic and aseptic revision THA. Patients received either ciNPT or a silver-impregnated dressing (control) for 7 days. Wound complications within 90 days of the procedure were recorded, including: surgical site infection (SSI), periprosthetic joint infection (PJI), prolonged drainage greater than 5 days, erythema requiring antibiotics, and hematoma formation. An a priori power analysis determined 201 patients per cohort were necessary to demonstrate a 10% decrease in wound complication rate.

Introduction

Patients with aseptic loosening, a cause of failure in uncemented total joint arthroplasty (TJA), often present with fibrous tissue at the bone-implant interface.¹ In this study, we characterize the presence of neutrophil extracellular traps (NETs) in the intramedullary fibrotic membrane of aseptic loosening patients. We further explore the role of NETs, mediated by peptidyl arginine deiminase (PAD4), in peri-implant fibrosis and osseointegration failure through a murine model of unstable tibial implantation.^2–4

Methods

Peri-implant membrane was retrieved from five patients during total hip revision surgery and analyzed for the presence of NETs (citH3+ with extracellular DNA) via immunofluorescence. A Ti-6Al-4V implant was inserted in an oversized drill-hole in the right proximal tibia of 8-week-old C57BL/6J and PAD4 knockout mice (n=3 per group). Fourteen days later, all mice were euthanized, and implanted tibias were dissected. Fibrosis and osseointegration at the bone-implant interface were assessed by micro-computed tomography (microCT) and hematoxylin and eosin (H&E) staining. H&E samples were scored blindly by the investigator and another observer for signs of poor (score=0) to excellent osseointegration (score=3) using a rubric established in our lab.

Background

Ultraporous metals have now been used in acetabular reconstruction for two decades with excellent survival. The purpose of this study is to evaluate a newer porous metal made from Ti6Al4V titanium alloy in complex primary and revision hip arthroplasty.

Methods

A retrospective review as performed on all total hip arthroplasty (THA) procedures in which a G7 Osseo-Ti (Zimmer Biomet, Warsaw, IN) acetabular component was used between 2015 and 2017. Patients with 2-year minimum follow-up or failure were included, yielding a cohort of 123 patients (126 hips). There were 50 male patients (41%; 51 hips) and 73 females (59%; 75 hips). Mean age was 65 years (range, 43–88) and mean BMI was 30.7 kg/m² (range, 18–56). Indications for ultraporous metal components were in hips with compromised bone stock or severe acetabular deformity. Procedures were 35 complex primary THA and 91 revision THA that included 12 conversions and 24 reimplantations as part of 2-staged exchange for treatment of infection.

Introduction

Previous reports have investigated the correlation between time to revision hip arthroplasty (rTHA) and reason for revision, but little is known regarding the impact of timing on outcomes following rTHA. The purpose of this study is to evaluate the effect of time to rTHA on both indication and outcomes of rTHA.

Methods

This retrospective observational study reviewed patients who underwent unilateral, aseptic rTHA at an academic orthopedic specialty hospital between January 2016 and April 2019 with at least 1-year of follow-up. Patients were early revisions if they were revised within 2 years of primary THA (pTHA) or late revisions if revised after greater than 2 years. Patient demographics, surgical factors, and post-operative outcomes were compared between the groups. Post-hoc power analysis was performed (1-β=0.991).

Background

Modular dual mobility (MDM) acetabular components are often used to prevent dislocation in revision total hip arthroplasty (THA). As there is insufficient data on these components, the outcomes were evaluated in a cohort with a mean follow-up time of greater than five years.

Methods

Using the database of a single academic center, 126 revision THAs (117 patients) with one MDM were retrospectively reviewed. There were 94 hips in 88 patients with a mean follow-up time of 5.5 years. Survivorship analysis was performed with the endpoints of dislocation, reoperation for dislocation, cup revision for aseptic loosening, and cup revision for any reason. The secondary endpoints were perioperative complications and radiographic review.

Introduction

The prevalence of ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is rising in concert with life expectancy, putting more patients at risk for interprosthetic femur fractures (IPFF). Our study aimed to assess treatment methodologies, implant survivorship, and clinical outcomes of patients with IPFF.

Methods

77 patients treated for an IPFF from 1985–2017 at a single large referral center were reviewed. Prior to the fracture, at the hip/knee sites respectively 46 femurs had primary/primary, 21 had revision/primary, 3 had primary/revision and 7 had revision/revision components. Mean age and BMI were 74 years and 30 kg/m², respectively. Mean follow-up after fracture treatment was 7 years.

Introduction

Quality measures play a substantial role in the Centers for Medicare and Medicaid Services' hospital payment and public reporting programs. The purpose of this study was to assess whether public measurement of total hip and knee arthroplasty risk-standardized readmission (RSRRs) and complication rates (RSCRs) was temporally associated with decreasing rates of adverse outcomes among Medicare beneficiaries.

Methods

We evaluated annual trends in hospital-level risk-standardized complication and readmission rates in the fiscal years 2010–11 and 2016–17 for patients undergoing hospital-based inpatient hip/knee replacement procedures. We calculated hospital-level rates using the same measures and methodology used in public reporting. We examined annual trends in the distribution of hospital-level outcomes through density plots (similar to histograms).

Background

The Comprehensive Care for Joint Replacement (CJR) model was implemented in April-2016 to standardize cost and improve quality of care for two of the most commonly billed inpatient procedures for Medicare patients, total knee and total hip arthroplasty. The purpose of this study is to compare one institution's predicted savings and losses under the CJR model with actual savings and losses after two years of implementation and discuss new methods to maintain savings.

Methods

Using our institution's data, we calculated the mean cost per episode of care. We calculated the percent reduction in target price and percent savings or losses per case for the CJR and Bundle Payment Care Initiative (BPCI) for each Medicare Severity Diagnosis Related Group (MS-DRG) using mean cost per episode and CJR and BPCI target prices. We compared the target prices, annual savings, and losses per episode of care for both CJR and BPCI. All CJR savings, projected and actual, were computed by comparing CJR savings to that of 2018 BPCI savings.

Introduction

With the removal of total hip arthroplasty (THA) from the Centers for Medicare & Medicaid Services (CMS) inpatient-only list, understanding predictors of length of stay (LOS) after THA is critical. Thus, we aimed to determine the influence of patient- and procedure-related risk factors as predictors of >1-day LOS after THA.

Methods

A prospective cohort of 5,281 patients underwent primary THA between January 2016 and April 2019. Risk factors increased LOS were categorized as patient-related (demographics, smoking status, baseline Veterans RAND 12 Item Health Survey Mental Component Summary score [VR-12 MCS], Charlson Comorbidity Index [CCI], surgical indication, baseline Hip Injury and Osteoarthritis Outcome Score [HOOS] pain subscore and baseline HOOS physical function shortform (HOOS-PS), range of motion, and predicted discharge disposition) or procedure-related (hospital site, surgeon, approach, day of surgery, and surgery start time). By using the Akaike information criterion (AIC) and internally-validated concordance probabilities (C-index) for discriminating a 1-day LOS from a >1-day LOS, we compared performance between a patient-related risk factors only model and a model containing both patient- and procedure-related risk factors.

Background

Direct anterior approach (DAA), total hip arthroplasty (THA, performed with the patient in the supine position, creates a unique opportunity to do bilateral THA under one anesthesia. Previous studies evaluating this option are limited by small sample size or lack of control group. The purpose of this study is to compare early clinical outcomes of simultaneous bilateral, unilateral and staged bilateral DAA-THA.

Methods

Using an institutional registry database, we reviewed 3977 DAA-THA performed in 3334 patients at minimum 90-days follow up. A single surgeon performed all surgeries. Simultaneous bilateral DAA-THA group included 512 hips in 256 patients, unilateral DAA-THA group 2691 hips and staged bilateral DAA-THA group 774 hips in 387 patients. We reviewed 90-day postoperative complications, readmissions, length of stay, and rate of home discharge between all three groups.

Introduction

The proportion of arthroplasties performed in the ambulatory setting has increased substantially. However, concerns remain regarding whether same-day discharge may increase the risk of complications. The purpose of this study was to compare 90-day outcomes between inpatients and patients having surgery at an ambulatory surgery center (ASC).

Methods

Among a single-surgeon cohort of 721 patients who underwent arthroplasty at a free-standing ASC, 611 (84.7%) were matched one-to-one to inpatients based on age, gender, American Society of Anesthesiologists (ASA) score, and Body Mass Index (110 patients could not be adequately matched). The cohort included 208 total hip arthroplasties (34.0%), 196 total knee arthroplasties (32.1%), 178 unicompartmental knee arthroplasties (29.1%), 25 hip resurfacings (4.1%), two revision hip arthroplasties (0.3%) and two revision knee arthroplasties (0.3%). Post-operative outcomes including readmissions, reoperations, unplanned clinic visits, emergency department visits, and complications were compared. Complications were classified as either major (i.e. death, periprosthetic joint infection, pulmonary embolism) or as minor (i.e. delayed wound healing, rashes, urinary retention).

Introduction

Prosthetic joint infection (PJI) is an devastating complication after total hip arthroplasty (THA). The common treatment in the US is a two-stage exchange which can be associated with significant morbidity and mortality. The purpose of this study was to analyze complications in the treatment course of patients undergoing two-stage exchange for PJI THA and determine when they occur.

Methods

We analyzed all patients that underwent two-stage exchange arthroplasty for treatment of PJI after THA from January 2005 – December 2017 at a single institution. Complications were categorized as medical or surgical, divided into three intervals: (1) inter-stage, (2) early post-reimplantation (<90 days) and (3) late post-reimplantation (> 90 days). Minimum follow up was one year. Success was based on the Musculoskeletal Infection Society (MSIS) definition.

Introduction

Debridement, antibiotics, and implant retention (DAIR) for acute prosthetic hip infection is a popular low morbidity option despite less than optimal success rates. We theorized that the delay between DAIR and explantation in failed cases may complicate eradication due to biofilm maturation and entrenchment of bacteria in periprosthetic bone. We ask, what are the results of two-stage reimplantation after a failed DAIR versus an initial two-stage procedure?

Methods

114 patients were treated with 2-stage exchange for periprosthetic hip infection. 65 were treated initially with a 2-stage exchange, while 49 underwent an antecedent DAIR prior to a 2-stage exchange. Patients were classified according to MSIS host criteria. Failure was defined as return to the OR for infection, a draining sinus, or systemic infection.

Introduction

Total hip replacement failure due to fretting-corrosion remains a clinical concern. We recently described that damage within CoCrMo femoral heads can occur either by mechanically-dominated fretting processes leading to imprinting (via rough trunnions) and surface fretting (via smooth trunnions), or by a chemically-dominated etching process along preferential corrosion sites, termed “column damage”. These corrosion sites occur due to banding of the alloy microstructure. Banding is likely caused during thermo-mechanical processing of the alloy and is characterized by local molybdenum depletion. It was the objective of this study to quantify material loss from femoral heads with severe corrosion, identify the underlying damage modes, and to correlate the damage to the alloy's microstructure.

Methods

105 femoral heads with a Goldberg score 4 were evaluated. Coordinate measuring machine data was used to compute material loss and visualize damage features. Time in situ and stem alloy were identified. Metallographic samples were produced for each case. Grain size and banding were identified using light-microscopy. Mann-Whitney tests were conducted to compare material loss between groups.

Introduction

Modular neck (MN) components in total hip arthroplasty (THA) offer intraoperative flexibility, but adverse local tissue reactions (ALTR) due to tribocorrosion at modular junctions are a potential complication of such designs. Serum ion levels and metal artifact reduction sequence (MARS) MRI are used to assess ALTR following modular THA. This study investigates serum ion levels and MARS MRI findings in a series of hips with MN components and differing articulating surfaces.

Methods

We retrospectively evaluated a cohort of 184 primary THAs in 159 patients implanted with a dual modular femoral stem by one surgeon from 2005–2013. 121 THAs had a cobalt-chromium neck component and non-metal-on-metal articulation, while 63 THAs had a titanium neck component and metal-on-metal (MoM) articulation. Serum ion levels were recorded for all patients. MARS MRI scans were read by musculoskeletal-trained radiologists. Pseudotumor grade and location were measured.

Introduction

Elective surgery elicits a systemic immune response and may result in immunosuppression in certain patients. It is currently unknown whether patients are at an increased risk for viral infection and associated illness in the immediate postoperative period following total joint arthroplasty. This question has become more important given the ongoing coronavirus disease 2019 (COVID-19) pandemic.

Methods

We analyzed 3 large administrative datasets (Medicare 5% and 100% standard analytic files, Humana claims database) to identify patients who underwent total knee arthroplasty (TKA) and total hip arthroplasty (THA) from 2005 to 2013. The influenza vaccination status of each patient was defined using the presence or absence of a code for vaccination. The incidence of a flu diagnosis was recorded in both vaccinated and unvaccinated patients at 1 month, 3 months, and 6 months following the date of surgery and was compared to a cohort of vaccinated patients who did not undergo surgery.

Background

There remains a paucity of clinical studies on the effects of coronavirus on perioperative outcomes, with no existing trials reporting on risk factors associated with increased risk of postoperative mortality in these patients. The objectives of this study were to assess perioperative complications and identify risk factors for increased mortality in patients with coronavirus undergoing surgery.

Methods

This multicentre cohort study included 340 coronavirus negative patients versus 82 coronavirus positive patients undergoing surgical treatment for neck of femur fractures across nine NHS hospitals within Greater London, United Kingdom. Predefined study outcomes relating to patient demographics, fracture configuration, operative treatment, perioperative complications and mortality were recorded by observers using a standardised data collection proforma. Univariate and multivariate analysis were used to identify risk factors associated with increased risk of mortality.

Introduction

In Europe a femoral neck retaining stem (Metha, Aesculap Inc, Tuttlingen, Germany) has been reported with excellent midterm survivorship. We report on a US series and compare it to a review of reports in Europe over the past decade to determine if US experience matches that in Europe.

Methods

A review of published studies was performed on PubMed with search terms: Hip, replacement, arthroplasty, and Metha. We found four publications that met the criteria of reporting survivorship and reasons for revision surgery. The results from these four articles combined had 4179 THA with the Metha stem. After IRB approval three orthopaedic groups in the US were used to combine their experience over the last 11 years. These US sources had 824 surgeries performed between 2008–2019. We then reported on all revisions for comparison of survivorship.

Introduction

The purpose of this study was to evaluate the long term changes in bone mineral density (BMD) following implantation of a low-modulus composite femoral component designed to closely match the stiffness of the proximal femur and minimize stress shielding. Specifically, we asked: 1) How does BMD in the proximal femur change with time and with Gruen zone location; 2) Does BMD in the proximal femur stabilize after two years of implantation?

Methods

We retrospectively reviewed a subgroup of sixteen patients who had preoperative and postoperative DEXA scans in an FDA multi-center prospective trial of this composite stem. Five of these sixteen patients returned for long-term DEXA scans at a mean 22.0 years post-op (range 21.2–22.6 years). BMD in the 7 Gruen zones at final follow-up was compared to immediate post-operative and 2-year follow-up values. Percentage change was calculated and change in BMD was plotted against time from immediate post-operative measurements to each subsequent follow-up.

Introduction

In the United States, cementless femoral fixation remains the dominant mode of fixation for femoral neck fractures, despite strong worldwide registry data that supports cemented fixation. The reason for this discrepancy remains unknown, controversial and often difficult to compare due to multiple variables. The purpose of this study was to evaluate a matched cohort of patients undergoing arthroplasty for femoral neck fractures and assess outcomes of revisions, periprosthetic fractures and mortality.

Methods

This is an exact matched cohort study. Cemented fixation cases were exact matched to cementless fixation cases in a 1:1 fashion based on age, sex and Charlson Comorbidity Index (CCI). Outcome variables included: revision for periprosthetic fracture; all cause revision and mortality at any time point; all cause revision and mortality within 1-year and within 90-days. The primary independent variable was femoral fixation (cemented, cementless) and covariates included race (black, white, other), ethnicity (hispanic, non-hispanic), teaching status (minor, major, nonteaching) and bedsize (1–99, 100–399, >=400). Chi-square tests and multivariable logistic regression models were used for statistical analysis.

Introduction

Patients with FNF may be treated by either total hip arthroplasty (THA) or hemiarthroplasty (HA). Utilizing American Joint Replacement Registry (AJRR) data, we aimed to evaluate outcomes in FNF treatment.

Methods

Medicare patients with FNF treated with HA or THA reported to the AJRR database from 2012–2019 and CMS claims data from 2012–2017 were analyzed in this retrospective cohort study. “Early” was defined as less than 90 days from index procedure. A logistic regression model, including index arthroplasty, age, sex, stem fixation method, hospital size¹, hospital teaching affiliation¹, and Charlson comorbidity index (CCI), was utilized to determine associations between index procedure and revision rates.

Introduction

While interdisciplinary protocols and expedited surgical treatment improve management of geriatric hip fractures, the impact of such interventions on patients undergoing specifically arthroplasty for femoral neck fracture (FNF) has not been well studied. The aim of this study is to evaluate the efficacy of an interdisciplinary hip fracture protocol for patients undergoing arthroplasty for acute FNF.

Methods

In 2017, our tertiary care institution implemented a standardized interdisciplinary hip fracture protocol. We conducted a retrospective review of adult patients who underwent hemiarthroplasty (HA) or total hip arthroplasty (THA) for FNF from July 2012 – March 2020, and compared patient characteristics, hospitalization characteristics, and outcomes between those treated before and after protocol implementation.

Introduction

The purpose of the study was to determine access to and, ability to use telemedicine technology in an adult hip and knee reconstruction patient population and we seek to understand these patients' perceived benefits, risks and preferences of telemedicine.

Methods

We performed a cross-sectional telephone administered survey on patients scheduled to undergo primary THA and TKA by one of six surgeons at a single academic institution between March 23 and June 2, 2020.

Introduction

Recent literature has sought to quantify pre-operative work associated with total joint arthroplasty. These studies have utilized surveys or self-reported time logs to estimate the Pre-op Optimization Work (POW) completed by the surgical team. The purpose of this study was to objectively quantify POW associated with total hip arthroplasty (THA) using electronic medical record (EMR) activity audit logs.

Methods

Retrospective analysis of EMR activity for 4 arthroplasty surgeons and their clinical staff was collected for 100 consecutive THA cases (25 per surgeon). Clinical informatics data was generated using EMR activity audit logs for pre-THA activity. Every action and mouse-click within a patient's chart was recorded for each team member. The time between mouse-clicks was calculated and summed for each user. Times exceeding five minutes without activity were assumed to reflect inactivity and excluded. Descriptive statistics were used to estimate the POW associated with THA preparation.

Background

The purpose of this study is to evaluate the early outcomes with the use of a smartphone-based exercise and educational platform after primary total hip arthroplasty compared to a standard of care control group.

Methods

A multicenter prospective randomized control trial was conducted evaluating the use of the mymobility smartphone-based care platform for primary total hip arthroplasty (THA). Patients randomized to the control group (198 patients) received the respective institution's standard of care. Those randomized to mymobility treatment group (167 patients) were provided an Apple Watch and mymobility smartphone application. The application provides pre and postoperative educational content, video directed exercise programs as well as tracks the patient's activity. Patients in the treatment group were not initially prescribed physical therapy, but could be if their surgeon deemed it necessary. Early outcomes assessed included 90-day hip range of motion, HOOS JR scores, 30-day single leg stance (SLS) and time up and go (TUG) test.

We also evaluated PT utilization, THA complications associated with readmissions, ER visits not associated with readmissions, urgent care (non standard of care) visits, and physician office visits.

Outcome scores include HOOS-Jr, EQ-5D-5L, single stance (SLS), Timed up and go (TUG).

Satisfaction scores for the procedure and the mymobility study group were also recorded.

Introduction

The association between preoperative opioid use and adverse outcomes after total hip arthroplasty (THA) has been reported. However, a quantitative assessment used to evaluate the combined effect of controlled substance use and define a threshold for adverse outcomes after THA has not been established. The current study aimed to identify the association between the NarxCare Score (NCS) (indicative of controlled substance use) and length of stay (LOS), discharge disposition, 90-day emergency department (ED) visits, readmission, and reoperation after primary THA, necessary to identify a preoperative NCS threshold for adverse outcomes.

Methods

A total of 2,787 THAs (57.3% female; mean age: 64.3±11.14 years; NCS range: 0–800) were performed between November 2018-January 2020 at an integrated healthcare system with preoperative NCSs. Outcomes assessed included LOS, discharge disposition, 90-day ED visits, readmission (all-cause, procedure and non-procedure-related) and reoperation. The association between NCS category (in 100-point increments) and was analyzed through multivariate logistic regression accounting for risk factors.

Introduction

Venous thromboembolism (VTE), defined as either pulmonary embolism (PE) or deep venous thrombosis (DVT), is a rare, but serious complication following total hip arthroplasty (THA). Current VTE guidelines recommend pharmacologic agents with or without intermittent pneumatic compression devices (IPCDs). At our institution, both 81mg aspirin (ASA) twice a day (BID) and portable IPCDs were prescribed to THA patients at standard risk for VTE. The aim of this study is to determine if discontinuing the use of portable outpatient IPCDs is safe and does not increase the rate of VTE in patients undergoing THA.

Methods

A retrospective review of 1,825 consecutive THA cases was conducted identifying patients with a VTE 90-days postoperatively. Patients were divided into two separate consecutive cohorts. Cohort one consisted of THA patients who received outpatient IPCDs for a period of 14 days (control). Cohort two consisted of THA patients without outpatient IPCDs (experimental). Patients were non-randomized to 81mg ASA BID for 28 days for VTE chemoprophylaxis. An interim power analysis was performed to determine the proper sample size.

Introduction

The number of total hip arthroplasties (THAs) performed per year is increasing for reasons that are not fully explained by a growing and aging population. The purpose of this study was to determine the role of patient health status as an indication for surgery and determine if patients are undergoing surgery at a better health status than in the past.

Methods

To examine how pre-operative functional health status has changed over time, a systematic review and meta-analysis of the Medline, Embase, and Cochrane databases was performed in accordance with the PRISMA guidelines. Health status was assessed using the physical component summary (PCS) score from the 36-item short-form (SF-36) health survey. Only primary procedures were included; revisions were excluded. Articles were screened by two independent reviewers with conflicts resolved by consensus with a third reviewer. Meta-regression analysis was performed to determine the effect of time, patient age, and gender. Subgroup analysis was performed to assess differences between countries.