The gold standard treatment of hip dysplasia is a peri-acetabular osteotomy (PAO). Labral tears are seen in the majority of patients presenting with hip dysplasia and diagnosed using Magnetic Resonance Imaging (MRI). The goal was to (1) evaluate utility/value of MRI in patients undergoing hip arthroscopy at time of PAO, and (2) determine whether MRI findings of labral pathology can predict outcome.

A prospective randomized controlled trial was conducted at tertiary institutions, comparing patients with hip dysplasia treated with isolated PAO versus PAO with adjunct hip arthroscopy. This study was a subgroup analysis on 74 patients allocated to PAO and adjunct hip arthroscopy (age 26±8 years; 89.2% females). All patients underwent radiographic and MRI assessment using a 1.5-Tesla with or 3-Tesla MRI without arthrography to detect labral or cartilage pathology. Clinical outcome was assessed using international Hip Outcome Tool-33 (iHOT).

74% of patients (55/74) were pre-operatively diagnosed with a labral tear on MRI. Among these, 41 underwent labral treatment (74%); whilst among those without a labral tear on MRI, 42% underwent labral treatment (8/19). MRI had a high sensitivity (84%), but a low specificity (56%) for labral pathology (p=0.053). There was no difference in pre-operative (31.3±16.0 vs. 37.3±14.9; p=0.123) and post-operative iHOT (77.7±22.2 vs. 75.2±23.5; p=0.676) between patients with and without labral pathology on MRI.

Value of MRI in the diagnostic work-up of a patient with hip dysplasia is limited. MRI had a high sensitivity (84%), but low specificity (44%) to identify labral pathology in patients with hip dysplasia. Consequently, standard clinical MRI had little value as a predictor of outcome with no differences in PROM scores between patients with and without a labral tear on MRI. Treatment of labral pathology in patients with hip dysplasia remains controversial. The results of this subgroup analysis of a prospective, multi-centre RCT do not show improved outcome among patients with dysplasia treated with labral repair.

It has been reported that 60-85% of patients who undergo PAO have concomitant intraarticular pathology that cannot be addressed with PAO alone. Currently, there are limited diagnostic tools to determine which patients would benefit from hip arthroscopy at the time of PAO to address intra-articular pathology. This study aims to see if preoperative PROMs scores measured by IHOT-33 scores have predictive value in whether intra-articular pathology is addressed during PAO + scope. The secondary aim is to see how often surgeons at high-volume hip preservation centers address intra-articular pathology if a scope is performed during the same anesthesia event.

A randomized, prospective Multicenter trial was performed on patients who underwent PAO and hip arthroscopy to treat hip dysplasia from 2019 to 2020. Preoperative PROMs and intraoperative findings and procedures were recorded and analyzed. A total of 75 patients, 84% Female, and 16% male, with an average age of 27 years old, were included in the study. Patients were randomized to have PAO alone 34 patients vs. PAO + arthroscopy 41 patients during the same anesthesia event. The procedures performed, including types of labral procedures and chondroplasty procedures, were recorded. Additionally, a two-sided student T-test was used to evaluate the difference in means of preoperative IHOT score among patients for whom a labral procedure was performed versus no labral procedure.

A total of 82% of patients had an intra-articular procedure performed at the time of hip arthroscopy. 68% of patients who had PAO + arthroscopy had a labral procedure performed. The most common labral procedure was a labral refixation which was performed in 78% of patients who had a labral procedure performed. Femoral head-neck junction chondroplasty was performed in 51% of patients who had an intra-articular procedure performed. The mean IHOT score was 29.3 in patients who had a labral procedure performed and 33.63 in those who did not have a labral procedure performed P- value=0.24.

Our findings demonstrate preoperative IHOT-33 scores were not predictive in determining whether intra-articular labral pathology was addressed at the time of surgery. Additionally, we found that if labral pathology was addressed, labral refixation was the most common repair performed. This study also provides valuable information on what procedures high-volume hip preservation centers are performing when performing PAO + arthroscopy.

Residual Legg-Calve-Perthes (LCP) deformities represent one of the most challenging disorders in hip reconstructive surgery. We assessed mid-term PROMs, radiographic correction, complications and survivorship of combined surgical dislocation (SD) and periacetabular osteotomy (PAO) for the treatment of complex LCP deformities.

A longitudinal cohort study was performed on 31 hips with complex LCP deformities undergoing combined SD/PAO. Treatment included femoral head reshaping, trochanteric advancement and relative neck lengthening, management of intra-articular lesions and PAO. Twenty-seven (87.1%) had minimum 5-year follow up. Average age was 19.8 years with 56% female and 44% having previous surgery.

At a mean 8.4 years, 85% (23/27) of the hips remain preserved (no conversion to THA). The survivorship estimates at 5 and 10 years were 93% and 85%, respectively. The median and interquartile range for mHHS increased from 64 [55–67] to 92 [70–97] (p<0.001), the WOMAC-pain improved from 60 [45–75] to 86 [75–100] (p= 0.001). An additional 19% (n=5) reported symptoms (mHHS <70) at final follow-up. UCLA activity score increased from a median of 8 [6–10] to 9 [7–10] (p=0.207). Structural correction included average improvements of acetabular inclination 15.3^o ± 7.6, LCEA 20.7° ± 10.8, ACEA 23.4° ± 16.3, and trochanteric height 18 mm ± 10 mm (all, p<0.001). Complications occurred in two (7%) patients including one deep and one superficial wound infection.

At intermediate follow-up of combined SD/PAO for complex LCP deformities, 85% of hips are preserved. This procedure provides reliable deformity correction, major pain relief, improved function and acceptable complication/failure rates.

The unparalleled events of the year 2020 continue to evolve and challenge the worldwide community on a daily basis. The COVID-19 pandemic has had a major impact on all aspects of our lives, and has caused major morbidity and mortality around the globe. The impact of COVID-19 on the practice of orthopedic surgery has been substantial with practice shutdowns, elective surgery restrictions, heightened utilization of telemedicine platforms and implementation of precautionary measures for in-person clinic visits. During this transition period the scholarly and educational pursuits of academic surgeons have been de-emphasized as the more immediate demands of clinical practice survivorship have been the priority. This unavoidable focus on clinical practice has heightened the importance of orthopedic subspecialty societies in maintaining an appropriate level of attention on research and educational activities. Under the outstanding presidential leadership of Robert Barrack, MD, The Hip Society adapted to the profound challenges of 2020, and maintained strong leadership in the realms of education and research. The recent 2020 summer meeting of the Hip Society was a testimonial to the resilience and dedication of the Society members to ongoing innovation in research and education. Due to travel and social distancing restrictions the 2020 summer meeting was transitioned from an in-person to a virtual meeting format. Dr Barrack and Program Chair Dr John Clohisy assisted with oversight of the meeting, while Olga Foley and Cynthia Garcia ensured the success of the meeting with remarkable planning and organization. These collaborative efforts resulted in an organized, well-attended, high level scientific meeting with engaging discussion and a remarkable virtual conference environment.

The Bone & Joint Journal is very pleased to partner with The Hip Society to publish the proceedings of this very unique virtual meeting. The Hip Society is based in the United States and membership is granted to select individuals for leadership accomplishments in education and research related to hip disease. The Society is focused on the mission of advancing the knowledge and treatment of hip disorders to improve the lives of patients. The vision of the Hip Society is to lead in the discovery and dissemination of knowledge related to disorders of the hip. The annual closed meeting is one of the most important events of the society as this gathering highlights timely, controversial and novel research contributions from the membership.

The top research papers from The Hip Society meeting will be published and made available to the wider orthopedic community in The Bone & Joint Journal. This partnership with The Bone & Joint Journal enhances the mission and vision of The Hip Society by international dissemination of the meeting proceedings. Given the far-reaching circulation of The Bone & Joint Journal the highest quality work is available to an expanding body of surgeons, associated healthcare providers and patients. Ultimately, this facilitates the overarching Hip Society goal of improving the lives of our patients.

The 2020 virtual Hip Society meeting was characterized by outstanding member attendance, high quality paper presentations and robust discussion sessions. The meeting was held over two days and encompassed 58 open paper presentations divided into ten sessions with moderated discussions after each session. All papers will be presented in this issue in abstract form, while selected full papers passing our rigorous peer review process will be available online and in The Bone & Joint Journal in a dedicated supplement in 2021.

The first session of the meeting focused on issues related to complex primary THA and osteonecrosis of the femoral head. Dr Gross presented on the conversion of hip fusion to THA in 28 patents at a mean 7 years. He reported a high clinical success rate, yet complications of heterotopic ossification and neurologic injury were relatively common. Consideration of heterotopic ossification prophylaxis and the selective use of a constrained liner were recommended. Dr Pagnano summarized the use of various contemporary porous acetabular components in 38 hips in the setting of prior pelvic radiation. The mean follow-up was 5 years and 10 year survivorship was 100% with all implants radiographically fixed. Dr Bolognesi's study demonstrated that THA in solid organ transplant patients is associated with higher risk for facility placement, transfusions and readmissions. This patient population also has increased mortality risk (4.3% risk at 1 year) especially lung transplant patients. The second group of papers focused on femoral head osteonecrosis. Dr Iorio presented single center data demonstrating that CT scan was a useful adjunct for diagnosis in the staging work-up for cancer, yet was not useful for ARCO staging and treatment decision-making. On the basic science side, Dr Goodman utilized a rabbit model of steroid-induced femoral head osteonecrosis to determine that immunomodulation with IL-4 has the potential to improve bone healing after core decompression. The session was concluded by Dr Nelson's study of ceramic-on-ceramic THA in 108 osteonecrosis patients. The median 12 year results were outstanding with marked increases in PROs, maintenance of high activity levels, and a 3.7% revision rate.

In the second session attention was directed to THA instability and spinopelvic mobility. Dr Sierra presented a machine learning algorithm for THA dislocation risk. Two modifiable variables (anterior/lateral approach, elevated liner) were most influential in minimizing dislocation risk. Dr Taunton's study demonstrated a deep learning artificial intelligence model derived from postoperative radiographs to predict THA dislocation risk. High sensitivity and negative predictive value suggest that this model may be helpful in assessing postoperative dislocation risk. In reviewing a large single-center, multiple surgeon cohort of 2,831 DAA procedures, Dr Moskal noted a very low dislocation rate (0.45%) at minimum 2 years. Importantly, spinopelvic pathology or prior spinal instrumentation was not associated with an increased dislocation risk (0.30%). Dr Huo and colleagues analyzed pelvic tilt during functional gait in patients with acetabular dysplasia. They detected variable pelvic tilt on different surfaces with the data suggesting that patients with more anterior pelvic tilt while standing tend to have greater compensatory posterior pelvic tilt during gait. Dr Lamontagne reported on the sagittal and axial spinomobility in patients with hip OA, and highlighted reductions in pelvic tilt, pelvic-femoral-angle, lumbar lordosis and seated maximal trunk rotation when compared to controls. Dr Dennis showed that differences in spinopelvic mobility may explain the variable accuracy of acetabular version measurements on the cross-table lateral radiographs. Dr Gwo-Chin presented on a comprehensive functional analysis of 1,592 patients undergoing THA and observed that spinopelvic abnormalities are not infrequent (14%) in THA patients. Consistent with these findings Dr Murphy and collaborators identified a low prevalence of previous spinal instrumentation (1.5%), yet a high prevalence of spine stiffness (27.6%) in 149 patients undergoing THA.

Session three highlighted various aspects of treating hip disease in young patients. Dr Peters investigated the need for subsequent hip arthroscopy in 272 patients treated with an isolated PAO. Only 4.8% of these patients required subsequent arthroscopy calling into question the routine use of combined arthroscopy and PAO. Three papers addressed questions related to THA in young patients. Dr Berend's study of 2532 hips demonstrated that high activity level was not associated with an increased risk of midterm aseptic or all cause failure. Dr Nunley presented on 43 young patients with an average age of 52 years treated with a cementless stem and modular dual mobility articulation. Stress shielding was minimal and no concerning metal ion release detected. Dr Garvin summarized minimum 15 year data of THA with highly cross-linked polyethylene in patient less than 50 years. These hips performed exceptionally well with no mechanical loosening or radiographic osteolysis. Dr Engh examined 10 year results of the Birmingham Hip Resurfacing implant and reported a 92.9 % overall survivorship, with males less than 55 years achieving a 98.3% survivorship. The session was concluded by long-term data on the Conserve Plus hip resurfacing arthroplasty. Dr Amstutz presented an impressive dataset depicting an 83.1% 20 year survivorship for this early resurfacing cohort.

Direct anterior approach total hip arthroplasty was the focus of session four. Dr Meneghini reported on the anesthesia and surgical times of direct anterior and posterior approaches from a large healthcare system database. These data suggested longer OR and surgical times for the DAA both in the inpatient and ASC environments. Dr Clohisy introduced the technique and early outcomes of lateral decubitus position DAA. In a learning curve experience of 257 hips. 96% of acetabular components were in the Lewinneck safe zone, the aseptic revision rate was 0.9% and there were no dislocations. Dr Beaule analyzed femoral stem cement mantle with the DAA and posterior approaches by comparing two matched cohorts. Stem alignment and cement mantle quality were equivalent with both approaches. Similarly, Dr Emerson demonstrated technical feasibility and fewer cemented femoral stem failures when compared to cementless stems in a series of 360 DAAs THAs. The final paper of the session presented by Dr Hamilton examined the impact of surgical approach on dislocation after isolated head and liner exchange. Neither the posterior nor the anterior approach was superior in reducing the dislocation rate for these high dislocation risk procedures.

The fifth session explored contemporary topics related to anesthesia and pain management. Dr Byrd opened the session with a comparative study evaluating general versus spinal anesthesia for hip arthroscopy. This preliminary study was provoked by the desire to minimize aerosolized exposure early in the COVID-19 pandemic by transitioning to spinal anesthesia. Both anesthetic methods were effective. Dr Austin presented a randomized, double-blind controlled trial comparing spinal anesthetic with mepivacaine, hyperbaric bupivacaine and isobaric bupivacaine. Mepivacaine patients ambulated earlier and were more likely to be discharged the same day. Dr Mont provided a very timely study on the effects of “cannabis use disorder” and THA outcomes. This administrative database study of 44,154 patients revealed this disorder to be associated with longer hospital stays, increased complications rates and higher costs. Dr Bedair investigated whether a highly porous acetabular component submerged in an analgesic solution could enhance perioperative pain management. Interestingly, this novel strategy was associated with a reduction of postoperative pain scores and opioid consumption in 100 experimental patients compared to 100 controls. The concluding paper of the session by Dr Della Valle examined whether decreased discharge opioids led to increased postoperative opioid refills. A large single-center study of 19,428 patients detected a slight increase (5%) in opioid refills but a reduction in total refill morphine milligram equivalents.

The final, sixth session of day one considered various challenging aspects of revision hip arthroplasty. Dr Nam started the session with review of preliminary results from a randomized control trial comparing closed incision negative-pressure therapy with a silver-impregnated dressing for wound management in 113 hips undergoing revision arthroplasty. Unlike previous reports, the negative pressure therapy was associated with a higher reoperation rate for wound-related complications. Dr Bostrom highlighted the potential clinical impact of basic biological interventions by establishing the presence of Neutrophil Extracellular Traps (NETS) in fibrotic tissue from human aseptic loosening specimens and in a murine model of unstable tibial implantation. NET inhibition in the murine model prevented the expected tibial implant osseointegration failure. Dr Lombardi presented early 3.3 year clinical results of a highly porous Ti6al4v acetabular component in complex primary and revision arthroplasty. Survivorship for aseptic loosening was 96.6 % and 95.3% for the primary and revision cases, respectively. Dr Schwarzkopf and colleagues explored the impact of time to revision arthroplasty on clinical outcomes. Analysis of 188 revision cases revealed early revisions (less than 2 years from primary) were associated with worse outcomes, longer hospitalizations and higher reoperation rates. Mid-term results for modular dual mobility implants in revision arthroplasty were reviewed by Dr Lachiewicz who reported on 126 hips at a mean 5.5 years. 11% of hips dislocated and the 6 year survival was 91%. An outer head diameter of 48mm or greater was associated with a lower risk of dislocation. Dr Berry concluded the session by discussing the outcomes of treating the challenging problem of interprosthetic femur fractures. A single-center study of 77 cases treated over 32 years demonstrated a 79% success rate free of reoperation at 2 years with 95% of patients being ambulatory.

The second day commenced with the seventh session evaluating recent strategies to improve short-term THA outcomes. Dr Bozic and colleagues investigated the association of quality measure public reporting with hip/knee replacement outcomes. Annual trend data from 2010–2011 and 2016–2017 indicate that hospital-level complication and readmission rates decease after the start of public reporting, yet it is difficult to prove a direct effect. Dr Slover reviewed his institutions experience with the Comprehensive Care for Joint Replacement (CJR) model and emphasized that lower CJR target prices make it increasingly difficult for programs to meet target price thresholds. Cost saving strategies including same day discharge and reduction of home health services may result in smaller losses of positive margins. Dr Barsoum reported on the influence of patient and procedure-related risk factors of length of stay after THA. Patient-related risk factors provided substantial predictive value yet procedure-related risk factors (hospital site and surgical approach) remain the main drivers of predicting length of stay. Dr Hozack reviewed an impressive, single surgeon cohort of 3,977 DAA THAs and analyzed adverse events and 90 day perioperative outcomes. Simultaneous bilateral DAA THA was comparable with unilateral or staged bilateral procedures in regards to complications, readmission rate and home discharge rate but with an increased risk of transfusion. To examine the risk of complications with outpatient joint arthroplasty, Dr Della Valle performed a single-surgeon matched cohort analysis comparing outpatient and inpatient hip and knee arthroplasties. Outpatient procedures were not associated with an increased risk of any postoperative complications and actually experienced fewer emergency department visits.

The eighth session covered various contemporary challenges in hip arthroplasty care. Dr Griffin began the session with an analysis of the timing of complications associated with two-stage exchange procedures for periprosthetic joint infection (PJI). Of the 189 hips included, 41.6% had a complication and the mortality was 14.1% at 2.5 years, highlighting the morbidity of this treatment method. Dr Fehring provided data assessing the fate of two-stage reimplantation after failed debridement, antibiotics and implant retention (DAIR) for a prosthetic hip infection. This analysis of 114 hips yielded concerning results demonstrating a 42.9% treatment failure of patients treated with a previous DAIR compared to a 12.3% failure rate in patients treated with an initial 2-stage procedure. Dr Jacobs reviewed the analysis of 106 femoral heads with severe corrosion and identified a chemically dominated etching process termed “column damage” to be a detrimental damage mode within CoCr femoral heads that is directly linked to banding within its microstructure. These data indicate that implant alloy microstructure must be optimized to minimize the release of fretting-corrosion products. Simon Mears presented retrospective data from 184 THAs with a dual modular femoral stem. A subgroup of hips with a modular, cobalt chromium femoral neck had a pseudotumor visualized in 15% with only 55% of these having elevated CoCr levels. These findings may support the use of routine follow-up MARS MRI for modular CoCr femoral neck prostheses. The final two studies explored timely issues related to viral illness and hip surgery. Dr Browne analyzed three large administrative databases to elucidate whether patients are at increased risk for viral illnesses following total joint replacement. The incidence of postoperative influenza after total joint replacement was not increased compared to patients not undergoing total joint replacement surgery suggesting that arthroplasty procedures may not heighten the risk of viral illness. In the final paper of the session Dr Haddad presented important data regarding perioperative complications in coronavirus positive patients undergoing surgical treatment of femoral neck fractures. In this multicenter cohort study from the United Kingdom 82 coronavirus positive patients were shown to have longer hospital stays, more critical care unit admissions, higher risk of perioperative complications and an increased mortality compared to 340 coronavirus negative patients.

The eighth session had two papers on alternative femoral stem designs and three presentations more focused on femoral fracture treatments. Dr Mihalko focused on the European and US experiences with the Metha femoral neck retaining stem. The US experience mirrored the encouraging results from Europe with a 94% all cause femoral survivorship and a 99.1% femoral aseptic loosening survivorship at 5 years. Dr Kraay summarized dual energy x-ray absorptiometry (DEXA) evaluation of 16 low modulus composite femoral components at long-term follow-up of a mean 22 years. The bone mineral density associated with the implant increased in Gruen zones 2–6 and showed limited decreases in zones 1 and 7. These data support the concept that a low modulus femoral stem may more effectively load the proximal femur. Dr Springer provided data from the American Joint Replacement Registry (AJRR) and by evaluating outcomes of exact matched cohorts of 17,138 patients treated with cementless or cemented femoral implants for femoral neck fractures. Cemented implants were associated with marked reduction in early revision and periprosthetic fractures. However, cemented fixation was associated with an increased mortality at 90 days and 1 year. Additional data from the AJRR was presented by Dr Huddleston who investigated the risk factors for revision surgery after arthroplasty in a cohort of 75,333 femoral neck fractures. THA when compared to hemiarthroplasty was associated with higher early and overall revision rates. Cementless femoral fixation and increased age were also associated with higher rates of any revision. Both of these studies from the AJRR suggest that further consideration should be given to femoral fixation preferences in the femoral neck fracture population. Dr Vail summarized his institution's experience with an interdisciplinary hip fracture protocol for patients undergoing arthroplasty for acute femoral neck fractures. His study compared 157 cases prior to protocol implementation with 114 patients treated after the protocol was established. The impact of the interdisciplinary protocol was impressive as evidenced by a reduced time to operative treatment, length of stay, complication rate and one-year mortality. All being achieved without an increase in readmissions or facility discharges.

The final session of the meeting addressed innovations in perioperative care of THA patients. Dr Barrack started the session with an interesting study examining the feasibility and patient preferences regarding telemedicine. A cross-sectional telephone survey of 163 arthroplasty patients indicated that 88% of patients use the internet and 94% own a device capable of videoconferencing. Nevertheless, only 18% of patients preferred a video visit over an in-person clinic visit due to concerns of inferior care. Dr Barnes quantified preoperative optimization work in 100 arthroplasty patients by using EMR activity logs and determined the surgical team spends an average 75 minutes per case on preoperative work activities. Dr Duwelius reported the early outcomes of primary THA with a smartphone-based exercise and educational platform compared to standard of care controls. A randomized control trial design with 365 patients demonstrated similar outcomes and non-inferiority of the smartphone platform relative to complications, readmissions, emergency room/urgent care visits. The association of controlled substance use with THA outcomes was assessed by Dr Higuera Rueda. A quantitative assessment using the NarxCare score identified 300 and above as a score associated with adverse outcomes after THA. Dr Macaulay reviewed data from a large retrospective study of 1,825 THAs indicating that discontinuation of intermittent pneumatic compression devices does not increase the risk of venous thromboembolism in standard risk patients being treated with 81mg ASA BID as prophylaxis. Dr Antoniou presented the final paper of the meeting investigating potential changes in patient health status as an indication for surgery over time. Data from this large systematic review of the literature found patients undergoing THA at similar health status to the past with no influence form patient age, gender, year of enrollment or geographic region.

As summarized above, the 2020 virtual Hip Society Summer Meeting was rich in scientific content, productive discussion and a collaborative spirit. This collective body of work will result in impactful scientific contributions and will serve as a foundation for future innovation and advancements in the treatment of hip disease.

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.

The purpose of this study was to examine a cohort of patients with minor acetabular dysplasia features in order to identify the preoperative clinical characteristics and imaging findings that differentiate patients with hip instability from patients with impingement.

A retrospective cohort study of patients with borderline acetabular dysplasia was performed. All patients were identified by prospective radiographic evaluation with an LCEA between 20° and 25°. Multivariate statistical analyses were used to identify independent predictors of disease type.

Of the 143 hips in the cohort, 39.2% (n=56) had the diagnosis of instability, while 60.8% (n=87) had the diagnosis of impingement. The cohort included 109 females (76.2%) and 34 males (23.8%).

Hips with instability had a lower LCEA (21.8° vs. 22.8°; p<0.001), lower ACEA (23.3° vs. 26.6°; p=0.002), a higher AI (11.8° vs. 8.5°; p<0.001), and a lower maximum alpha angle (54.4° vs. 61.1°; p=0.001). The odds of instability increased 1.7 times for each one-degree decrease in LCEA, 1.4 times for each one-degree decrease in ACEA, and 1.1 times for each one-degree increase in acetabular inclination (all p0.003). Female sex was strongly associated with instability.

The instability subgroup had greater range of motion (IRF, 22.7° vs. 12.4°, p<0.001) and total arc of motion (IRF+ERF, 61.2° vs. 47.4°, p<0.001). We identified predictors of diagnosis including: acetabular inclination (1.49, p<0.001), ACEA (0.89, p=0.007), crossover sign (0.27, p=0.014), preoperative mHHS (0.96, p=0.014), IRF (1.10, p=0.001), and age (0.88, p=0.001).

Patients with symptomatic instability tend to have increased acetabular inclination, decreased ACEA, greater functional limitations, younger, greater IRF, while hips with impingement demonstrate the opposite trends.

Introduction

Acetabular dysplasia is associated with an increased risk of hip pain and early development of osteoarthritis (OA). The Bernese peri-acetabular osteotomy (PAO) is the most well-established technique in the Western world for the treatment of symptomatic acetabular dysplasia. This case-control study aims to assess whether the severity of acetabular dysplasia has an effect on outcome following Peri-Acetabular Osteotomy (PAO) and/or the ability to achieve desired acetabular correction.

Surface replacement arthroplasty (SRA) has been proposed as a viable option for the treatment of osteoarthritis in young, active patients. Positive results of the Birmingham Hip Resurfacing (BHR) in select patient groups have been described in international series and registry data. We report 5–10 year U.S. follow-up for the BHR at our high volume institution.

314 patients (361 hips) between 2006–2011 underwent BHR at our institution and agreed to participate in research. Demographic features, modified Harris Hip Score, UCLA Activity Score, and satisfaction were recorded for patients with minimum 5-year follow-up (90%). Radiographs were evaluated for implant position and “at risk” signs. Complications, reoperations, and revisions were investigated.

Mean modified Harris Hip and UCLA scores significantly improved postoperatively to scores of 89.96 and 7.90 (p < 0.001), respectively. Kaplan-Meier estimated survival for all-cause revision was 96.7% [95% CI 94.7 – 98.7%] at 5 years and 91.5% [95% CI 85.3 – 97.6%] at 10 years. Estimated survival for aseptic revision in males less than 60 years old with a primary diagnosis of osteoarthritis was 99.5% [95% CI 98.7 – 100%] at 5 years and 98.8% [95% CI 97.0 – 100%] at 10 years. 14 patients required revision, including 5 revisions for adverse local tissue reaction.

Our study demonstrated excellent survivorship and clinical outcomes at 5–10 year follow up for the BHR. These results mirror other series and registry data published outside of the United States. Continued long-term follow-up and additional studies are necessary to validate the long-term safety and outcomes of the BHR, especially in young active arthroplasty patients.

Developmental dysplasia of the hip (DDH) represents a heterogeneous group of deformities that are commonly associated with secondary osteoarthritis. Affected hips may require total hip arthroplasty (THA) for endstage disease and these cases can present unique challenges for the reconstructive surgeon. While the severity of deformity varies greatly, optimizing THA can be challenging even in the “mildly” dysplastic hip. These disorders are commonly characterised by acetabular deficiency with inadequate coverage of the anterolateral femoral head and proximal femoral abnormalities including excessive femoral antetorsion, coxa valga and femoral stenosis. In more severe cases, major femoral head subluxation or dislocation can add additional complexity to the procedure. In addition to the primary deformities of DDH, secondary deformities from previous acetabular or proximal femoral osteotomies may also impact the primary THA. Primary THA in the DDH hip can be optimised by detailed understanding of the bony anatomy, careful pre-operative planning, and an appropriate spectrum of techniques and implants for the given case. This presentation will review the abnormal hip morphologies encountered in the dysplastic hip and will focus on the more challenging aspects of THA. These include acetabular reconstruction of the severely deficient socket and in the setting of total dislocation, femoral implant procedures combined with corrective osteotomy or shortening, and issues related to arthroplasty in the setting of previous pelvic osteotomy. Despite the complexity of reconstruction for various dysplastic variants the clinical outcomes and survivorship of these procedures are good to excellent for most patients. Nevertheless, more complex procedures are associated with an increased complication rate and this should be considered in the surgical decision-making process.

Over the past fifteen years hip preservation surgery has rapidly evolved. Improved understanding of the pathomechanics and associated intra-articular degeneration of both hip instability and femoroacetabular impingement have led to improved surgical indications, refined surgical techniques and more effective joint preservation surgical procedures. The periacetabular osteotomy (PAO) was initially introduced by Ganz and colleagues and has become the preferred treatment in North America for pre-arthritic, symptomatic acetabular dysplasia. Both hip arthroscopy and safe surgical dislocation of the hip have been popularised for the treatment of symptomatic femoroacetabular impingement disorders. Hip arthroscopy is effective for focal and\or accessible impingement lesions while the surgical dislocation approach is reserved for nonfocal disease patterns as seen in complex FAI, and residual Perthes and SCFE deformities. Femoroacetabular impingement from major acetabular retroversion can be managed with the PAO if there is coexistent posterosuperior acetabular insufficiency. Short- to mid-term results of these procedures are generally good to excellent for most patients and the complication rates associated with these procedures are very acceptable. Long-term outcomes are best known for the PAO. Several recent studies have documented survivorship rates of 65–90% at 10–20-year follow-up. Certain factors are associated with long-term success including minimal pre-operative radiographic OA, early symptoms, accurate acetabular correction, and younger age. These data strongly suggest that the PAO can defer THA to an older age for most patients while completely avoiding arthroplasty may only be possible in select patients with excellent congruency, no secondary OA and an ideal surgical correction.

Introduction

The first highly crosslinked and melted polyethylene acetabular component for use in total hip arthroplasty was implanted in 1998 and femoral heads larger than 32mm in diameter introduced 2004.

The purpose of this study was to re-assemble a previous multi-center patient cohort in order to evaluate the radiographic and wear analysis of patients receiving this form of highly crosslinked polyethylene articulating against large diameter femoral heads at a minimum of 10 years follow-up.

Introduction

The first highly crosslinked and melted polyethylene acetabular component for use in total hip arthroplasty was implanted in 1998. Numerous publications have reported reduced wear rates and a reduction in particle induced peri-prosthetic osteolysis at short to mid-term follow-up.

The purpose of this study was to re-assemble a previous multi-center patient cohort in order to evaluate the radiographic and wear analysis of patients receiving this form of highly crosslinked polyethylene articulating against 32mm femoral heads or less at a minimum of 13 years follow-up.

Introduction

Total hip replacements using highly cross-linked polyethylene show excellent clinical outcomes, low wear, and minimal lysis at 5 years follow-up. A recent RSA study reports a significant increase in femoral head penetration between 5 and 7 years. This study is a multi-center radiographic analysis to determine whether the RSA observation is present in a large patient cohort.

Studies of patients having primary THR using highly cross-linked polyethylene show excellent clinical outcomes and very low radiographic wear results at a minimum of 5 years follow-up. Recently, a radiostereometric analysis (RSA) study of a small group of patients reported that after no detectable wear during years 1–5, they found a significant increase in femoral head penetration between 5 and 7 years follow-up. However, this increase in head penetration after 5 years has not been confirmed in a larger patient cohort.

The purpose of this study was to organize a multicenter radiographic study involving leading medical centers in the U.S. having the longest-term follow-up available on this type of highly cross-linked polyethylene in order to determine if the RSA observation can be confirmed in a larger study.

Six academic centers agreed to contribute radiographic data to this study. All patients received primary total hip replacements with Longevity polyethylene liners (Zimmer, Warsaw, IN) coupled with 26, 28, and 32mm cobalt chrome femoral heads. The radiographic inclusion criteria required a minimum of four radiographs per patient: one at 1 year; at least one from 2 to 4.5 years; one 4.5 to 5.5 years; and at least one from 5.5 to 9 years follow-up. The Martell Hip Analysis Suit-eTM software was used for the wear analysis. All wear values were determined by calculating head penetration between the follow-up radiograph and the 1-year radiograph to remove creep, the majority of which has been shown to occur during the first year. Separate linear regressions, representing the wear rates, were computed for the early period from 1 year to 5.5 years and the late period from 5.5 years to 9 years follow-up. The Zar test was used to determine the significance of the difference between these two linear regressions.

We present the completed analysis of 165 hips. When the early and late data points were combined into one data set, the second-order regression indicated an inflection point at 6.3 years with a slightly positive inflection. There were 402 film comparisons in the early time period, and the slope and confidence interval of the regression line was 4.9μm/yr (95% CI of −28μm/yr to 38μm/yr). There were 188 film comparisons in the late period, and slope of the regression line for the late period was 10.8 μm/yr (95% CI of −58μm/yr to 80μm/yr). The Zar test showed no significant difference between the two slopes (Figure 1, p=0.886).

No significant increase in femoral head penetration was found for the late period after 5 years compared to the early period before 5 years follow-up in either analysis. Additionally, no significant late increase in wear was seen within individuals. While we continue to enroll patients, at this time we do not observe the increase in wear seen in the RSA study after 5 years.

Purpose: Femoroacetabular impingement (FAI) is a precursor to osteoarthritis (OA) of the hip. To investigate the fate of impingement abnormalities we analyzed the contralateral hip in patients undergoing THA for advanced FAI. Our purpose was to determine the bilaterality of FAI abnormalities, and to describe the prognosis of these deformities.

Method: We reviewed 508 patients ≤50 years of age treated with THA. Radiographic review identified 70 hips that had OA secondary to FAI (71% cam, 5% pincer, 24% combined). Bilaterality was determined radiographically, and the fate of the contralateral hip was analyzed by determining radiographic presence and progression of OA, and the need for subsequent THA.

Results: 71% of the patients were male and the average age was 43.2 years. The contralateral hip was analyzed on radiographs over an average 9 year period (range, 4–30 years). 100% of the contralateral hips had radiographic features of FAI. 49 (70%) of the contralateral hips demonstrated degenerative disease. 14 had advanced OA at presentation, 41 had progressive joint space narrowing, 25 had progression of Tonnis OA grade and 26 underwent subsequent THA. Statistical analysis showed that alpha angle, LCEA, joint space width, and head-neck ratio have strong predictive value for subsequent THA (p< 0.05).

Conclusion: This study demonstrates that FAI abnormalities are commonly bilateral and are associated with OA progression in the majority of hips. Patients diagnosed with FAI should have both hips monitored, and joint preservation surgery or THA considered when appropriate.

Introduction: Although there is no absolute diagnostic test for PPI, synovial leukocyte counts and neutrophil percentages have been reported to have high sensitivity and specificity making them valuable tests for diagnosis. However, no cut off value for the latter is agreed upon. This study intends to evaluate to define definite cut-off values for preoperative synovial fluid leukocyte count and PMN percentage that allow physicians to diagnose infection in a prosthetic joint.

Methods: We analyzed synovial fluid aspirated preoperatively from 593 total knee arthroplasties (161 infected; 432 aseptic) from three different institutions. Using ROC curves, we determined cut-off values with optimal accuracy in diagnosis of infection for fluid leukocyte count and PMN percentage. The sensitivity, specificity, and predictive values were calculated for the above cutoff values.

Results: The synovial fluid leukocyte count was higher in patients with PPI (median, 31 × 103 cell/μl) compared to aseptic joint arthroplasties (median, 0.219 × 103 cells/μl)(p< 0.0001). Similarly, the neutrophil percentage was higher in patients with PPI (median, 90%) than in those with noninfected joints (median, 26%)(p< 0.0001). The cut-off values for optimal accuracy in diagnosis of infection were 1760 cells/μl for fluid leukocyte count and 73% for PMN percentage. A fluid cell count > 1760 cells/μl had a PPV of 99% and NPV of 88%, while a neutrophil percentage > 73% yielded a PPV of 96% and NPV of 91%. Chi-square analysis revealed the fluid WBC count and the neutrophil percentage to be significantly associated with the diagnosis of infection (p< 0.0001).

Discussion: Synovial fluid leukocyte count and differential are useful adjuncts to ESR and CRP in the preoperative diagnosis for infection in TKA. This study has identified a cut-off value for leukocyte count and neutrophil percentage that can be used to diagnose infection in a prosthetic joint.

Purpose: Problem : Infection in TKA is a devastating yet common complication. 2-stage reimplant procedures are performed in the treatment of this condition. Purpose:To evaluate the clinical, radiographic, complications, and patient satisfaction results of 2nd stage reimplantation revision TKA with the use of a TTO. Technical aspects of TTO length, fixation, bypass, and complications are reported.

Methods: From 1996–2004 our database identified 25 revision TKA (12% of 206 revision TKA) performed using a TTO. In 20/25 cases the procedure was a 2nd stage reimplant. Demographics, infecting organism, Gustillo grade, clinical, radiographic, AORI defects, complications, patient satisfaction were evaluated prospectively. All patients were followed until radiographic union of the TTO.

Results: At a mean follow up of 22 mo(range,6–84) no patients were lost to follow-up. 24 (96%)TTO’s healed - 1 requiring revision ORIF. Prior to reimplantation, patients had undergone a mean of 3.3 prior knee surgeries(range,2–8). Prior extensor mechanism procedures had been performed in 43% of knees. Methicillin resistant staphylococcus was the infecting organism in > 50% of knees. 19 knees had a static cement spacer removed at revision. Time to 2nd stage reimplant was 39 weeks(range,15–68). Poor preop range of motion and stiffness (mean arc 430 , range 10–950) improved significantly postop (mean flexion 880 p< .05). 13 (56%) knees required an adjunctive extensor procedure at the time of TTO. TTO length averaged 8.8cm(range,8–10). Screws(15 knees), 2mm cables(6), wires(4) were used for TTO fixation. Mean stem bypass of the TTO was 63mm (−20 to 100). 21 (84%) patients were satisfied with the procedure, despite 8 knees(32%) requiring further surgery. 6 (24%) TTO complications occurred; 1 escape requiring fixation. All TTO’s had healed at recent follow up.

Conclusions: TTO is a useful procedure for exposure in 2nd stage revision TKA. TTO union is predictable(96%), despite technical complications. Recurrence of infection requiring further surgery did not compromise TTO results. Prior/concurrent extensor mechanism procedures were noted frequently.

Funding : Other Education Grant

Funding Parties : Wright Medical Technologies