bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ideal Femoral Head Size in Total Hip Arthroplasty Balances Stability and Volumetric Wear
Authors: Cross Michael B. , Nam Denis , Mayman David J. 
Published: January 2013

Background Over the last several years, a trend towards increasing femoral head size in total hip arthroplasty to improve stability and impingement free range of motion has been observed. Purpose The specific questions we sought to answer in our review were: (1) What are the potential advantages and disadvantages of metal-on-metal, ceramic-on-ceramic, and metal-on-polyethylene bearings? (2) What is effect that femoral head size has on joint kinematics? (3) What is the effect that large femoral heads have on bearing surface wear? Methods A PubMed search and a review of 2012 Orthopaedic Research Society abstracts was performed and articles were chosen that directly answered components of the specific aims and that reported outcomes with contemporary implant designs or materials. Results A review of the literature suggests that increasing femoral head size decreases the risk of postoperative dislocation and improves impingement free range of motion; however, volumetric wear increases with large femoral heads on polyethylene and increases corrosion of the stem in large metal-on-metal modular total hip arthroplasty (THA); however, the risk of potentially developing osteolysis or adverse reactions to metal debris respectively is still unknown. Further, the effect of large femoral heads with ceramic-on-ceramic THA is unclear, due to limited availability and published data. Conclusions Surgeons must balance the benefits of larger head size with the increased risk of volumetric wear when determining the appropriate head size for a given patient.
Ceramic-Ceramic Bearing: Too Unpredictable to Use it Regularly
Authors: Su Edwin P. 
Published: January 2013

Background Ceramic-on-ceramic (CoC) bearings have excellent tribologic properties because of the smoothness, hardness, and wettability of the material. Therefore, their use has been proposed in younger, active patients who may wear out a traditional metal-on-polyethylene bearing. The same material properties that are beneficial to tribology may also create problems, however. For example, squeaking and fracture of the bearing materials have been reported to occur. Purpose The purpose of this paper was to investigate the literature reporting the complications of ceramic bearings and attempt to provide insight into their implications. Methods The US National Library of Medicine Database (PubMed) was searched using the terms “ceramic-ceramic total hip replacement,” “complications,” “squeaking,” and “fracture.” Only clinical studies with a clear reporting of the incidence of these complications were included. Results The literature reports that squeaking of the CoC bearing occurs in a certain percentage of patients and is likely indicative of edge loading and excessive wear. Other factors, such as patient height, weight, range of motion, and implant design, may contribute to the propensity for squeaking. Fracture is a unique risk of the CoC articulation that requires revision surgery. Though improvements in manufacturing techniques have reduced the fracture risk to a very low percentage, the ceramic material remains susceptible to this complication by impingement and component malposition. Conclusions Because of these possible negative outcomes associated with the ceramic material, the CoC bearing is too unpredictable to use regularly, and its use should be limited to patients who would benefit the most from it.
Finite Element Analysis Examining the Effects of Cam FAI on Hip Joint Mechanical Loading Using Subject-Specific Geometries during Standing and Maximum Squat
Authors: Ng K. C. Geoffrey , Rouhi Gholamreza , Lamontagne Mario , Beaulé Paul E. 
Published: January 2013

Background Cam femoroacetabular impingement (FAI) can impose elevated mechanical loading in the hip, potentially leading to an eventual mechanical failure of the joint. Since in vivo data on the pathomechanisms of FAI are limited, it is still unclear how this deformity leads to osteoarthritis. Purpose The purpose of this study was to examine the effects of cam FAI on hip joint mechanical loading using finite element analysis, by incorporating subject-specific geometries, kinematics, and kinetics. Questions The research objectives were to address and determine: (1) if hips with cam FAI demonstrate higher maximum shear stresses, in comparison with control hips; (2) the magnitude of the peak maximum shear stresses; and (3) the locations of the peak maximum shear stresses. Methods Using finite element analysis, two patient models were control-matched and simulated during quasi-static positions from standing to squatting. Intersegmental hip forces, from a previous study, were applied to the subject-specific hip geometries, segmented from CT data, to evaluate the maximum shear stresses on the acetabular cartilage and underlying bone. Results Peak maximum shear stresses were found at the anterosuperior region of the underlying bone during squatting. The peaks at the anterosuperior acetabulum were substantially higher for the patients (15.2 ± 1.8 MPa) in comparison with the controls (4.5 ± 0.1 MPa). Conclusions Peaks were not situated on the cartilage, but instead located on the underlying bone. The results correspond with the locations of initial cartilage degradation observed during surgical treatment and from MRI. Clinical Relevance These findings support the pathomechanism of cam FAI. Changes may originate from the underlying subchondral bone properties rather than direct shear stresses to the articular cartilage.
The Accuracy of the Use of Functional Hip Motions on Localization of the Center of the Hip
Authors: Speirs Andrew D , Benoit Daniel L , Beaulieu Mélanie L , Lamontagne Mario , Beaulé Paul E. 
Published: January 2013

Background The hip joint is generally considered a ball-and-socket joint, the center of which is used as an anatomic landmark in functional analyses and by surgical navigation systems. The location of the hip center has been estimated using functional techniques using various limb motions. However, it is not clear which specific motions best predicted the functional center. Purpose This study aims to compare the predicted functional center of the hip evaluated from multiplanar circumduction and star motions, and to compare this functional center with the geometric center. Methods Eight hips in four fresh–frozen cadavers were used and verified as morphologically normal in CT scans. Three-dimensional motion of each lower limb was recorded using arrays of reflective markers rigidly attached to the femur and pelvis. Each hip was manipulated to produce circumduction or star motion, i.e., abduction–adduction and flexion extension. The hip was then dissected and the bearing surface traced with a probe, from which a best-fit sphere was calculated. The functional center was calculated from the motion data and compared to the geometric technique. Results There was no difference between the functional hip center predicted by circumduction or star motions, although this was offset from the geometric hip center by up to 14 mm. For all except two hips, the functional center was less than 6 mm from the geometric hip in each anatomic direction. Test–retest differences were smaller for circumduction than for star motions. Conclusions Estimation of the hip center based on motion of the femur relative to the pelvis could localize the geometric center of the joint within 14 mm and circumduction motions were more repeatable. Clinical Relevance Many surgical navigation systems make use of the functional hip center as a landmark for alignment or reconstruction. Errors associated with this would have a very minor influence in lower limb alignment, e.g., for knee reconstruction, but could affect proximal femoral geometry relevant to hip reconstruction.
Groin Pain after Metal on Metal Hip Resurfacing: Mid-Term Follow-Up of a Prospective Cohort of Patients
Authors: Illical Emmanuel , Belanger Heather , Kim Paul R. , Beaulé Paul E. 
Published: January 2013

Background and Purpose Groin pain after metal on metal hip resurfacing has been previously reported. The purpose of this study was to determine the natural history of a cohort of patients with groin pain after hip resurfacing previously reported on and incidence of revision surgery. Methods Our group previously reported an 18% incidence of groin pain at a mean of 18 months post hip resurfacing. This cohort of groin pain patients was prospectively followed. Patients were evaluated using a visual analog pain rating score, the University of California at Los Angeles (UCLA) Physical Activity Index, and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Functional outcome scores were compared from initial to latest follow up using the paired Student's t test. Further diagnostic evaluation and/or intervention or other complication was also recorded. Results The latest mean follow up from surgery was 63 ± 15 months. The mean pain rating, UCLA, and WOMAC scores all improved at latest follow up, although WOMAC score improvement was not statistically significant. Mean pain rating score improved from 5.2 ± 2.0 to 2.5 ± 1.4 ( p = 0.0001). UCLA activity score improved from 6.4 ± 2.0 to 6.9 ± 1.6 ( p = 0.03). Total WOMAC score improved from 75.6 ± 20.5 to 84.5 ± 14.8 ( p = 0.15). Only one patient was revised for an adverse local tissue reaction. Conclusion Groin pain post hip resurfacing has a multifactorial etiology, and in the vast majority of cases improves over time with no significant functional limitations. However, the surgeon should be aware of the many potential causes, and help minimize the possibility with proper patient selection and surgical technique.
Recurrence of Dislocation following Total Hip Arthroplasty Revision using Dual Mobility Cups was Rare in 180 Hips followed over 7 Years
Authors: Mertl Patrice , Combes Antoine , Leiber-Wackenheim Frédérique , Fessy Michel Henri , Girard Julien , Migaud Henri 
Published: January 2013

Background Dual mobility (DM) cups of mobile polyethylene were introduced to prevent total hip arthroplasty (THA) dislocation, but no large series with this design to treat recurrent instability have been reported. Purpose Our retrospective investigation ascertained the efficiency of DM cups in correction of recurrent dislocation and assessed any adverse effects. Methods One hundred eighty THAs with recurrent instability were revised to DM cups in 180 patients (mean age, 67.4 ± 11.7 years; range, 19 to 92 years). Thirty-one patients (17.2%) underwent at least one earlier THA revision, and 15 (10.3%) incurred non-union of the greater trochanter. Of the initial group in 2009, 145 patients had completed evaluations which included assessment of the Harris Hip Score and a radiographic assessment at a mean follow-up of 7.7 ± 2.2 years (range, 4 to 14 years). The rate of survival was calculated considering any reason for revision as failure. Results At follow-up, Harris hip score was 83.9 ± 16.1 (range, 21 to 100). Dislocation of the large articulation occurred in seven hips (4.8%), and only two recurred (1.4%) (one requiring additional revision). In addition, two intra-prosthetic dislocations of the small articulation (1.4%) were observed and needed revision surgery. The large number of earlier surgeries and non-union of the greater trochanter were related to recurrent instability. Two cups (1.4%) showed signs of definite loosening; six (4.1%) presented signs of possible loosening. Twenty-nine hips manifested femoral or acetabular osteolysis (20%), but only three were severe. Eight-year survival rate considering revision for any reason was 92.6% (95% CI, 85.5–96.4%). Conclusions This series indicates that DM cups are a viable option to treat recurrent THA instability. Their design provides a low risk of recurrent instability without increasing mechanical complications.
Neck-Preserving Femoral Stems
Authors: Rajakulendran Karthig , Field Richard E. 
Published: January 2013

Background Surgeons undertaking total hip arthroplasty (THA) routinely perform a distal femoral neck resection. It has been argued that retaining the femoral neck during THA can provide mechanical and biological advantages. Purposes The objectives of this study were to review: (1) the current evidence on the advantages of femoral neck preservation during THA and (2) the clinical and radiological outcome of neck-preserving femoral stems. Methods A search of the English-language literature on neck-preserving THA and on the individual neck-preserving implants was performed using PubMed, Ovid SP and Science Direct. Results Studies have indicated that neck preservation offers superior tri-planar implant stability and allows more accurate restoration of the hip geometry and biomechanics. The trend towards tissue sparing surgery has contributed to the development of bone-conserving short-stem implants that offer variable levels of neck preservation. Despite an initial learning curve, these implants have generated promising early clinical results, with low revision rates and high outcome scores. However, radiological evaluation of some neck-preserving implants has detected a characteristic pattern of proximal femoral bone loss with distal cortical hypertrophy. The long-term implications of this finding are not yet known. Conclusions Preserving the femoral neck during THA has biomechanical advantages. However, long-term outcome data are needed on neck-preserving femoral stems to evaluate on-going bone remodelling and assess implant performance and survival.
An Algorithmic Approach to Mechanical Hip Pain
Authors: Poultsides Lazaros A. , Bedi Asheesh , Kelly Bryan T. 
Published: January 2013

Background As our understanding of hip pathology evolves, the focus is shifting toward earlier identification of hip pathology. Therefore, it is vitally important to elucidate intra-articular versus extra-articular pathology of hip pain in every step of the patient encounter: history, physical examination, and imaging. Questions/Purposes The objective was to address the following research questions: (1) Can an algorithmic approach to physical examination of a painful non-arthritic hip provide a more accurate diagnosis and improved treatment plan? (2) Does an anatomical layered concept of clinical diagnosis improve diagnostic accuracy? (3) What are the diagnostic tools necessary for the accurate application of a four-layer (osteochondral, inert, contractile, and neuromechanical) diagnosis? Methods An unrestricted computerized search of MEDLINE was conducted. Different terms were used in various combinations. Results An algorithmic approach to physical examination of a painful nonarthritic hip, including history, physical examination (specific tests), and advanced imaging allow for better interpretation of debilitating intra- and extra-articular disorders and their effect on core performance. Additionally, it improves our understanding as to how underlying abnormal joint mechanics may predispose the hip joint and the associated hemipelvis to asymmetric loads. These abnormal joint kinematics (layer I) can lead to cartilage and labral injury (layer II), as well as resultant injury to the musculotendinous (layer III) and neural structures (layer IV) about the hip joint and the hemipelvis. The layer concept is a systematic means of determining which structures about the hip are the source of hip pathology and how to best implement treatment. Conclusions A clear understanding of the differential diagnosis of hip pain through a detailed and systematic physical examination, diagnostic imaging assessment, and the interpretation of how mechanical factors can result in such a wide range of compensatory injury patterns about the hip can facilitate the diagnosis and treatment recommendations.
Development of Polymeric Nanocarrier System for Early Detection and Targeted Therapeutic Treatment of Peri-Implant Osteolysis
Authors: Purdue P. Edward , Levin Adam S. , Ren Ke , Sculco Thomas P. , Wang Dong , Goldring Steven R. 
Published: January 2013

Background Extensive research has implicated inflammation as a necessary and causative factor in the development of peri-implant osteolysis, suggesting that such an inflammatory response is the sentinel event for the process. The potential to impact the clinical course of this condition is hampered by the lack of an effective medical therapy, as well as a limited ability for early detection prior to radiographically evident osteolysis. Advances in nanotechnology have allowed for the production of engineered water-soluble nanocarriers, which exploit changes in the microvascular architecture for selective distribution to inflamed tissues. Evaluation of the uptake of the nanocarriers in sites of inflammation has elucidated a novel mechanism of cellular uptake and retention of these particles. Purpose The current review discusses the development of a novel, biocompatible, water-soluble nanocarrier utilizing copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA), conjugated to imaging and therapeutic agents for the detection and targeted treatment of inflammatory conditions. Methods We performed Medline searches for the terms “periprosthetic osteolysis,” “murine osteolysis model,” “HPMA osteolysis,” and “HPMA inflammation.” These searches identified 631, 306, 1, and 6 articles, respectively. These were then manually searched for articles relevant to the development of mouse models for inflammatory osteolysis and the use of HPMA copolymer technology in mouse models of inflammation. Results Promising results in a small animal model of osteolysis have demonstrated the capability for detection prior to the development of bone loss, and have highlighted the utility of nanocarriers for selective drug delivery to the affected tissues. Conclusions Challenges to the clinical translation of HPMA nanocarriers in peri-implant osteolysis remain, and the future research directions necessary for human clinical application are reviewed.
The Relationship among Health Literacy, Health Knowledge, and Adherence to Treatment in Patients with Rheumatoid Arthritis
Authors: Quinlan Patricia , Price Kwanza O. , Magid Steven K. , Lyman Stephen , Mandl Lisa A. , Stone Patricia W. 
Published: January 2013

Background Patients with poor health literacy often lack the knowledge needed to manage their treatment. Objective The aim of this cross-sectional study is to determine whether health literacy is a predictor of health knowledge and/or adherence to medication treatment in patients with rheumatoid arthritis. Method The study was completed in an urban, outpatient rheumatology setting. Health literacy was measured using the Test of Functional Health Literacy in Adults. The Arthritis Knowledge Questionnaire was modified to measure medication specific health knowledge, and the Morisky Medication Adherence scale was used to measure adherence. Researchers used regression analyses to determine if health literacy was a predicator of knowledge and/or adherence. Results Participants ( N = 125) had high mean health literacy scores. The average medication knowledge score was 0.73. Adherence to medication regimen was 0.84. Controlling for patient covariates, health literacy was positively associated with education, race, and age. In adjusted analyses, health literacy was a significant predictor of health knowledge but not adherence. Race, neighborhood income, and confidence with contacting provider about medications were predictors of adherence. Conclusion Study findings indicate that health literacy is independently associated with medication knowledge but not medication adherence in patients with rheumatoid arthritis. These results provide useful information for planning initiatives to support individuals with disease self-management.
Bilateral Disruption of Soft Tissue Extensor Mechanism of Knee: Functional Outcome and Comparison to Unilateral Injuries
Authors: Monroy Alexa , Urruela Adriana , Egol Kenneth A. , Tejwani Nirmal C. 
Published: January 2013

Background Bilateral ruptures of the extensor mechanism are rare. Questions/Purpose The purpose of this study was to compare the clinical outcomes of operatively treated unilateral and bilateral knee soft tissue extensor mechanism injuries and to identify risk factors for bilateral disruption. Methods All patients operatively treated for a knee extensor mechanism injury were entered into a database and prospectively followed. Postoperative protocol was standardized for all patients. Demographic data, baseline characteristics, range of motion, complications, pain, and functional status were assessed. The main patient-reported outcome measures used in this study were the SF-36 Health Survey and the Lysholm Scale. Results Patients who sustained bilateral injuries were more likely to have one or more systemic medical conditions. There was no statistical difference between the groups with regard to mechanism of injury or body mass index. The average follow-up was 29 months (range 6–60 months). Patient-reported outcomes, in the form of the SF-36 Health Survey and Lysholm scores, were not significantly different between the two groups at final follow-up. Range of motion and quadriceps strength was also similar between the two cohorts. At latest follow-up, 88% of patients with unilateral injuries and 83% of patients with bilateral disruption were able to return to their pre-injury employment. Conclusion Operatively treated bilateral knee extensor mechanism disruptions fare similar to unilateral injuries with regard to ultimate functional outcome. The presence of one of more preexisting medical conditions was identified as a risk factor for bilateral tendinous disruption.
Autograft and Allograft Unite Similarly in Lateral Column Lengthening for Adult Acquired Flatfoot Deformity
Authors: Vosseller J. Turner , Ellis Scott J. , O'Malley Martin J. , Elliott Andrew J. , Levine David S. , Deland Jonathan T. , Roberts Matthew M. 
Published: January 2013

Background Lateral column lengthening (LCL) is used to address the forefoot abduction associated with the adult acquired flatfoot. This opening wedge osteotomy can be filled with either allograft or autograft bone. Questions/Purposes The investigators sought to determine union rates and any loss of correction in patients undergoing LCL with autograft versus allograft. Methods Over a 3-year period, 126 LCLs performed by five surgeons in 120 patients were reviewed. Autograft was used in 51 patients, allograft in 75 patients. Times to clinical and radiographic union were established for these patients. Any loss of correction of forefoot abduction as manifested by talonavicular uncoverage was recorded for those grafts that healed. Failure was defined as nonunion or loss of 50% or greater correction. The size of the implanted graft was assessed as a risk factor for failure. Results There were 20 total failures: seven in patients with autograft and 13 in patients with allograft ( p = 0.63). The size of the implanted graft was larger in those patients that did fail ( p = 0.04). Conclusions The rate of nonunion and loss of correction for LCL was not significantly different between allograft and autograft. The overall rate of nonunion may be higher than has previously been reported.