Cause Of Hip Osteoarthritis Research Articles

Revealing a Natural Model of Pre-Osteoarthritis of the Hip Through Study of Femoroacetabular Impingement.

Femoroacetabular impingement (FAI) is considered the mechanical cause of hip osteoarthritis (OA). Surgical intervention involves labrum repair and osteochondroplasty to remove the impingement, alleviating symptoms. Nevertheless, some patients progress to hip OA after surgery, indicating that factors other than mechanical abnormality are contributing to hip OA progression. This review article discusses our laboratory's studies on hip FAI and OA, undertaken to identify key molecular players in the progression of hip OA. Transcriptome analysis identified peroxisome proliferator activated receptor gamma (PPARγ) as a crucial molecule in early hip OA. PPARγ, widely expressed in chondrocytes, has a protective role in preventing OA, but its true mechanism remains unknown. We observed a dysregulation of DNA methyltransferase (DNMT) in the progression of hip OA, with high expression of DNMT1 and 3A and downregulation of DNMT3B. Moreover, we established that DNMT3A is the main molecule that is binding to PPARγ promoter CpG area, and hypermethylation of this area occurs during disease progression. This suggests that epigenetic changes are a main mechanism that regulates PPARγ expression. Finally, we developed a novel rabbit model of hip FAI and OA and are currently performing studies to validate our small-animal model to human FAI.

Normative values of the alpha angle and triangular index measured from the hip radiographs of an African population

IntroductionUndetected femoroacetabular impingement (FAI), caused by asphericity of the femoral head, has been implicated as a leading cause of hip osteoarthritis in later stages. Two known types of impingement of the femur head with the acetabulum include the cam-type and pincer type, and the alpha angle and triangular index are indices applied in determining the presence of FAI in a hip radiograph. ObjectiveTo determine the normal range and upper limit of normal of the alpha angle and triangular index of an African population using non-pathological hip radiographs. Materials and methodsHip radiographs of 104 subjects reported to be normal were retrospectively studied. The images were reassessed jointly by three radiographers and afterwards by three consultant radiologists. The alpha angle and triangular index of selected radiographs were measured with appropriate electronic callipers. Values obtained were correlated with the age and gender of the patients. ResultsThe mean ± SD of the alpha angle for the population studied was 46.70 ± 12.340 with a range of 33.300–96.820 (males: 45.09 ± 12.030, females: 47.32 ± 12.370), and the upper limit of normal obtained was 79.160. The mean triangular index was 1.71±1.38 with a range of 0.03–5.98 (males: 1.77 ± 1.39, females: 1.65 ± 1.36), 4.12 being the upper limit of normal. There was no statistically significant difference between measurements of both indices with age and gender. However, there was excellent agreement between and within raters for both measurements (alpha angle: 0.992; triangular index: 0.924). ConclusionThe upper limits of normal for the alpha angle and triangular index of the studied population are 79.160 and 4.12. Age and gender were independent of the values measured, and the measurements demonstrated excellent inter-rater and intra-rater agreement. A normal range is thus provided, with upper limits beyond which a possible femoroacetabular impingement may be diagnosed.

Prevalence of radiographic hip dysplasia in japanese population-based study

Objectives The purpose of this study was to measure the indices of radiographic developmental dysplasia of the hip (DDH) in a cross-sectional study of an elderly Japanese population. Methods Hip radiographs of 427 informed, voluntary Japanese community-dwelling individuals (279 female and 148 male) aged 50 to 96 years-old were obtained from Miyagawa village in Japan through a health screening. The hip radiographs were measured by a custom-written, semi-automated MATLAB program. The center edge (CE) angle, acetabular roof obliquity (ARO), acetabular head index (AHI), and minimum joint space width (mJSW) were measured. We examined the associations between gender, side-of-hip, and age group on radiographic DDH and hip osteoarthritis (OA). Results The mean CE angle was 31.0°. The mean ARO was 5.8°. The mean AHI was 88.2%. The mean mJSW was 4.0 mm. Of the total population, 29.9% had DDH and 4.0% had hip OA. Of those who had hip OA, 41.2% were secondary OA, and 58.8% were primary OA. The relationship between DDH and OA was not significant. Conclusion DDH is unlikely to be an important cause of hip OA in the present population-based study.

Can measurements from an anteroposterior radiograph predict pelvic sagittal inclination?

Pelvic sagittal inclination (PSI) is often evaluated in patients with hip pathology using lateral radiographs. However, it would be useful if PSI could be predicted from an anteroposterior radiograph since this film is ubiquitous in the evaluation of hip pathology. Herein, computer-modeling was applied to predict PSI from radiographic measurements assessed in the anteroposterior plane. Three-dimensional surface models of the pelvis, femur, and sacrum were reconstructed from computed tomography images of 50 women with hip dysplasia. This study cohort was selected as changes in PSI alter femoral head coverage, which is relevant to the diagnosis and treatment of hip dysplasia, a known cause of hip osteoarthritis. Five radiographic parameters commonly used to independently estimate PSI were evaluated after bone surfaces were projected to an anteroposterior plane, including the symphysis to sacrococcygeal joint distance (S-S distance), the pelvic foramen aspect ratio (PF ratio), the distance between the symphysis and a line connecting the femoral head centers (S-H distance), the sacro-femoral-pubic angle (SFP angle), and the pelvic vertical ratio (PVR). Regression models determined the ability of these parameters to predict PSI from -20° to 20° at 1° increment. All five parameters showed a strong correlation with the PSI (all r > 0.9). From the regression models, PSI was estimated with a median (maximum) absolute error of 3.6° (18.4°), 3.8° (17.7°), 5.2° (17.9°), 5.8° (28.8°), and 3.2° (23.5°) for the S-S distance, PF ratio, S-H distance, SFP angle, and PVR, respectively. The regression model for S-S distance had a mean slope of 2.18 that ranged from 1.98 to 2.41 when the sacrococcygeal joint was located superior to the symphysis. Results indicated that substantial errors occur when estimating the actual value of PSI from an anteroposterior radiograph. However, the change in PSI could be estimated from the S-S distance, which may aid surgeons to successfully increase head coverage through periacetabular osteotomy and to locate the acetabular cup in a functional position for total hip arthroplasty.

Expression profile of matrix metalloproteinases in the labrum of femoroacetabular impingement.

AimsFemoroacetabular impingement (FAI) is a potential cause of hip osteoarthritis (OA). The purpose of this study was to investigate the expression profile of matrix metalloproteinases (MMPs) in the labral tissue with FAI pathology.MethodsIn this study, labral tissues were collected from four FAI patients arthroscopically and from three normal hips of deceased donors. Proteins extracted from the FAI and normal labrums were separately applied for MMP array to screen the expression of seven MMPs and three tissue inhibitors of metalloproteinases (TIMPs). The expression of individual MMPs and TIMPs was quantified by densitometry and compared between the FAI and normal labral groups. The expression of selected MMPs and TIMPs was validated and localized in the labrum with immunohistochemistry.ResultsOn MMP arrays, most of the targeted MMPs and TIMPs were detected in the FAI and normal labral proteins. After data normalization, in comparison with the normal labral proteins, expression of MMP-1 and MMP-2 in the FAI group was increased and expression of TIMP-1 reduced. The histology of the FAI labrum showed disorderly cell distribution and altered composition of thick and thin collagen fibres. The labral cells expressing MMP-1 and MMP-2 were localized and their percentages were increased in the FAI labrum. Immunohistochemistry confirmed that the percentage of TIMP-1 positive cells was reduced in the FAI labrum.ConclusionThis study established an expression profile of MMPs and TIMPs in the FAI labrum. The increased expression of MMP-1 and MMP-2 and reduced expression of TIMP-1 in the FAI labrum are indicative of a pathogenic role of FAI in hip OA development.Cite this article: Bone Joint Res. 2020;9(4):173–181.

The association between periacetabular osteotomy reorientation and hip joint reaction forces in two subgroups of acetabular dysplasia

Acetabular dysplasia is primarily characterized by an altered acetabular geometry that results in deficient coverage of the femoral head, and is a known cause of hip osteoarthritis. Periacetabular osteotomy (PAO) is a surgical reorientation of the acetabulum to normalize coverage, yet its effect on joint loading is unknown. Our objective was to establish how PAO, simulated with a musculoskeletal model and probabilistic analysis, alters hip joint reaction forces (JRF) in two representative patients of two different acetabular dysplasia subgroups: anterolateral and posterolateral coverage deficiencies. PAO reorientation was simulated within the musculoskeletal model by adding three surgical degrees of freedom to the acetabulum relative to the pelvis (acetabular adduction, acetabular extension, medial translation of the hip joint center). Monte Carlo simulations were performed to generate 2000 unique PAO reorientations for each patient; from which 99% confidence bounds and sensitivity factors were calculated to assess the influence of input variability (PAO reorientation) on output (hip JRF) during gait. Our results indicate that reorientation of the acetabulum alters the lines of action of the hip musculature. Specifically, as the hip joint center was medialized, the moment arm of the hip abductor muscles was increased, which in turn increased the mechanical force-generating capacity of these muscles and decreased joint loading. Independent of subgroup, hip JRF was most sensitive to hip joint center medialization. Results from this study improve understanding of how PAO reorientation affects muscle function differently dependent upon acetabular dysplasia subgrouping and can be used to inform more targeted surgical interventions.

Incidence of femoro-acetabular impingement in adult Indian population on the basis of specific radiological findings: A prospective study

4Introduction: Femoroacetabular impingement is a major cause of early osteoarthritis of the hip, especially in young and active patients. It is characterized by an early pathologic contact during hip joint motion between acetabulum and femur that limits the physiologic hip range of motion,. Depending on clinical and radiographic findings, it can be pincer or cam type. Most patients (86%) have a combination of both forms. The role of imaging in femoroacetabular impingement is to evaluate the hip for abnormalities associated with impingement and to exclude arthritis, avascular necrosis, or other joint problems on radiographs. Materials and Methods: Between August 2010 and November 2010, 100 radiographs of pelvis with both hips and both hips lateral view of normal subjects were obtained and included in this study. All radiographic parameters of interest in the present study were assessed by three observers including one radiologist. The intraobserver and interobserver coefficients for the various parameters, assessed on a sub-set of fifty radiographs, ranged from 0.90 to 0.98 which was significant. All the 100 sets of 3 x-rays were studied in this manner. Discussion: The aim of our study was to determine the prevalence of femoroacetabular impingement in Indian population. Western countries have a proportionally higher rate of primary osteoarthritis of hip. It is increasingly coming to notice that radiographs of idiopathic osteoarthritis of hip show signs of femoroacetabular impingement. Therefore, there could be a causal association between femoroacetabular impingement and idiopathic osteoarthritis of hip. Conclusion: Femoroacetabular impingement is recognized condition causing hip pain in young active adults and is believed to be a cause of hip osteoarthritis. Further studies are still required to evaluate the nature of disease process, its natural history, actual cause and effect relationship between femoroacetabular impingement and osteoarthritis.

Protocol for a multi-centre randomised controlled trial comparing arthroscopic hip surgery to physiotherapy-led care for femoroacetabular impingement (FAI): the Australian FASHIoN trial

BackgroundFemoroacetabular impingement syndrome (FAI), a hip disorder affecting active young adults, is believed to be a leading cause of hip osteoarthritis (OA). Current management approaches for FAI include arthroscopic hip surgery and physiotherapy-led non-surgical care; however, there is a paucity of clinical trial evidence comparing these approaches. In particular, it is unknown whether these management approaches modify the future risk of developing hip OA. The primary objective of this randomised controlled trial is to determine if participants with FAI who undergo hip arthroscopy have greater improvements in hip cartilage health, as demonstrated by changes in delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) index between baseline and 12 months, compared to those who undergo physiotherapy-led non-surgical management.MethodsThis is a pragmatic, multi-centre, two-arm superiority randomised controlled trial comparing hip arthroscopy to physiotherapy-led management for FAI. A total of 140 participants with FAI will be recruited from the clinics of participating orthopaedic surgeons, and randomly allocated to receive either surgery or physiotherapy-led non-surgical care. The surgical intervention involves arthroscopic FAI surgery from one of eight orthopaedic surgeons specialising in this field, located in three different Australian cities. The physiotherapy-led non-surgical management is an individualised physiotherapy program, named Personalised Hip Therapy (PHT), developed by a panel to represent the best non-operative care for FAI. It entails at least six individual physiotherapy sessions over 12 weeks, and up to ten sessions over six months, provided by experienced musculoskeletal physiotherapists trained to deliver the PHT program. The primary outcome measure is the change in dGEMRIC score of a ROI containing both acetabular and femoral head cartilages at the chondrolabral transitional zone of the mid-sagittal plane between baseline and 12 months. Secondary outcomes include patient-reported outcomes and several structural and biomechanical measures relevant to the pathogenesis of FAI and development of hip OA. Interventions will be compared by intention-to-treat analysis.DiscussionThe findings will help determine whether hip arthroscopy or an individualised physiotherapy program is superior for the management of FAI, including for the prevention of hip OA.Trial registrationAustralia New Zealand Clinical Trials Registry reference: ACTRN12615001177549. Trial registered 2/11/2015 (retrospectively registered).

Properties of the cartilage layer from the cam-type hip impingement deformity

Femoro-acetabular impingement (FAI) is associated with significant acetabular cartilage damage and degenerative arthritis. To understand the contact stress and thus biomechanical mechanisms that may contribute to degeneration, the material behaviour of the cartilage layer is required. The objective of this study is to determine the fibril-reinforced poroelastic properties and composition of cartilage from cam deformities and to compare to those of normal cartilage. Patients undergoing surgical treatment of a symptomatic cam FAI deformity were recruited from the clinical practice of one of the authors. Osteochondral specimens were retrieved from the deformity during surgery using a trephine. Control specimens were retrieved from the anterior femoral head bearing surface during autopsy procedures. Indentation stress-relaxation tests were performed to determine the modulus (ES), Poisson’s ratio (ν) and permeability (k0) of the poroelastic component, and the strain-independent (E0) and -dependent (Eε) moduli of the fibril-reinforcement using finite element analysis and optimization. Safranin-O staining was used to quantify proteoglycan content. ES and ν were 71% and 37% lower, respectively, in Cam specimens compared to controls, and k0 was approximately triple that of Control specimens (p<0.05). No significant differences were seen in the fibrillar components, E0 and Eε. Proteoglycan content was substantially depleted in Cam specimens, and was correlated with ES, ν and k0. This study showed that cartilage from the cam deformity exhibits severe degeneration in terms of the mechanical behaviour and composition changes, and is consistent with osteoarthritis. This further supports the hypothesis that FAI is a cause of hip osteoarthritis.

Higher medially-directed joint reaction forces are a characteristic of dysplastic hips: A comparative study using subject-specific musculoskeletal models

Acetabular dysplasia is a known cause of hip osteoarthritis. In addition to abnormal anatomy, changes in kinematics, joint reaction forces (JRFs), and muscle forces could cause tissue damage to the cartilage and labrum, and may contribute to pain and fatigue. The objective of this study was to compare lower extremity joint angles, moments, hip JRFs and muscle forces during gait between patients with symptomatic acetabular dysplasia and healthy controls. Marker trajectories and ground reaction forces were measured in 10 dysplasia patients and 10 typically developing control subjects. A musculoskeletal model was scaled in OpenSim to each subject and subject-specific hip joint centers were determined using reconstructions from CT images. Joint kinematics and moments were calculated using inverse kinematics and inverse dynamics, respectively. Muscle forces and hip JRFs were estimated with static optimization. Inter-group differences were tested for statistical significance (p≤0.05) and large effect sizes (d≥0.8). Results demonstrated that dysplasia patients had higher medially directed JRFs. Joint angles and moments were mostly similar between the groups, but large inter-group effect sizes suggested some restriction in range of motion by patients at the hip and ankle. Higher medially-directed JRFs and inter-group differences in hip muscle forces likely stem from lateralization of the hip joint center in dysplastic patients. Joint force differences, combined with reductions in range of motion at the hip and ankle may also indicate compensatory strategies by patients with dysplasia to maintain joint stability.

Investigation of association between hip morphology and prevalence of osteoarthritis.

The cause of hip osteoarthritis (OA) remains unclear, morphologic abnormality of hip was thought to be a contributing factor to hip OA. The hypothesis was that there were subtle anatomical morphology differences of the hip between normal and OA subjects; the objective of this study was to explore these anatomical differences which are predisposing to hip OA based on CT 3D reconstruction. Ninety-three normal subjects (186 hips) and 66 mild-to-moderate hip OA subjects (132 hips) were recruited in this study. Three parameters of the head-neck relationship were assessed: translation, rotation and concavity. Translation was the potential translational movements of femoral head related to the neck’s axis. Rotation was described by the physeal scar to evaluate the rotation tendency of femoral head related to the neck at the head-neck junction. Concavity was used to assess the sphericity of the head as it joins the neck. The femoral neck anteversion angle and some parameters of the acetabulum: anteversion, inclination and CE angle were measured too. By comparison, it was found that OA subjects had less femoral head sphericity, head-neck junction concavity, acetabular and femoral neck anteversion angle; but greater acetabular coverage. These characteristics increased the risk of hip OA in OA subjects.

Biomechanical Implications of Corrective Surgery for FAI: An Evidence-based Review.

Femoroacetabular impingement (FAI) has been identified as a potential cause of hip osteoarthritis. The goal of FAI surgery is to relieve pain, and hopefully delay or prevent osteoarthritis of the hip. Several studies have now demonstrated favorable clinical outcomes after arthroscopic and open surgical correction of symptomatic FAI. The concept is restoration of normal hip anatomy may result in improved biomechanical function and kinematics of the hip, which may prevent or delay the progression of osteoarthritis. Although many clinical studies demonstrate restoration of "normal" anatomy, there are few studies evaluating improvement of biomechanics and function. To date, only 5 studies have been published in the English literature that study biomechanics and/or kinematics of the hip both preoperatively and postoperatively. At this point in the understanding of FAI, critical analysis of the literature suggests that FAI surgery can improve several parameters of biomechanical hip function. However, the impact of these improved biomechanics on the natural history and progression of degenerative changes in patients that are treated for symptomatic FAI has not been demonstrated.

A review of environmental factors implicated in human developmental dysplasia of the hip.

PurposeDevelopmental dysplasia of the hip (DDH) is common, and the term encompasses a spectrum of anatomical abnormalities of the hip in which the femoral head displaces from the acetabulum. These abnormalities may be congenital or develop during infancy and/or childhood. Neither the prenatal and postnatal factors that predispose to hip instability nor the determinants of its resolution or persistence are well characterised. A multifactorial pathogenesis of DDH is commonly accepted and identified risk factors include a family history, being first born, breech presentation, female gender, high birth weight and oligohydramnios 1. Further to genetic factors, a number of nutritional, hormonal and mechanical influences on ligament laxity have been hypothesised.MethodsA comprehensive search was conducted using NICE Healthcare Databases Advanced Search and Google Scholar engines, and the terms “nutrition”, “environmental”, “risk factors”, “CDH” and “DDH”. Wherever possible, evidence from randomised controlled trials, systematic reviews and expert review articles published in the medical and veterinary literature was considered.ResultsThe relationship between a number of hormones and biochemical markers of nutritional status and the development of DDH has been repeatedly hypothesised upon in the last 45 years. Of those most frequently cited are calcium, vitamins C and D, and relaxin hormone. The evidence for these potential risk factors is provided mainly by canine studies, with a paucity of consistent or strong evidence in humans.ConclusionsDDH is common and remains a leading cause of hip osteoarthritis in young adults. Neonatal clinical screening programmes for this condition have been in practice since the 1950s, albeit with varying levels of sensitivity. This review summarises current understanding of some of the most frequently cited nongenetic hypothesised risk factors, the significance of which remain to be determined.

Subclinical deformities of the hip are significant predictors of radiographic osteoarthritis and joint replacement in women. A 20 year longitudinal cohort study

Femoroacetabular Impingement (FAI) and Acetabular Dysplasia are common deformities, which have been implicated as a major cause of hip osteoarthritis (OA). We examined whether these subtle deformities of the hip are associated with the development of radiographic OA and total hip replacement (THR) in women. A population-based, longitudinal cohort of 1003 women underwent pelvis radiographs at years 2 and 20. Alpha Angle, Triangular Index Height, Lateral Centre Edge (LCE) angle and Extrusion Index were measured. An alpha angle of greater than 65° was defined as Cam-type FAI. Radiographic OA and the presence of a THR were then determined at 20 years. Cam-type FAI was significantly associated with the development of radiographic OA. Each degree increase in alpha angle above 65° was associated with an increase in risk of 5% (Odds Ratio (OR) 1.05 [95% confidence interval (CI) 1.01-1.09]) for radiographic OA and 4% (OR 1.04 [95% CI 1.00-1.08]) for THR. For Acetabular Dysplasia, each degree reduction in LCE angle below 28° was associated with an increase in risk of 13.0% (OR 0.87 [95% CI 0.78-0.96]) for radiographic OA and 18% (OR 0.82 [95% CI 0.75-0.89]) for THR. This study demonstrates that Cam-type FAI and mild Acetabular Dysplasia are predictive of subsequent OA and THR in a large female population cohort. These are independent of age, BMI and joint space and significantly improve current predictive models of hip OA development.

FRI0207 Prevalence of Femoroacetabular Impingement in Caucasians Compared to Chinese in Vancouver, Canada: A Population-Based Study

BackgroundFemoroacetabular Impingement (FAI) is one source of hip pain in young adults and has been suggested as a major cause of hip osteoarthritis (OA). The prevalence of radiographic hip OA...

Relationship of acetabular dysplasia in females with osteoarthritis of the hip to the distance between both anterior superior iliac spines

BackgroundAcetabular dysplasia (AD) is the main cause of hip osteoarthritis in Japan. A simple method to evaluate acetabular dysplasia would be helpful for early treatment or prevention of hip osteoarthritis. Acetabular dysplasia is reported to be associated with pathological transverse growth of the pelvis, indicating that the distance between the 2 anterior superior iliac spines might be useful for screening and detection of acetabular dysplasia. The purpose of this study was to determine if the acetabular dysplasia radiographic parameters are related to the distance between the 2 anterior superior iliac spines in patients with hip osteoarthritis.Material/MethodsIn this study, data obtained in a previous multi-institutional examination of patients with hip osteoarthritis in Japan were evaluated. The anterior superior iliac spine distances of 176 female patients (mean age, 54 years; range, 18–85 years) were measured by physical examination. The relationship between the anterior superior iliac spine distance and acetabular dysplasia was analyzed, and the anterior superior iliac spine distances of the patients with acetabular dysplasia who were at relatively high risk for hip osteoarthritis were compared with that of the patients at lower risk.ResultsA statistically significant relationship between the anterior superior iliac spine distance and all of the acetabular dysplasia parameters was observed. The anterior superior iliac spine distances of the acetabular dysplasia patients with a relatively high risk for radiographic acetabular dysplasia parameters were significantly smaller than those of patients at lower risk. Even after adjustment for age, height, and weight, significantly increased relative risk for having high risk AD was found in patients with an ASIS distance of less than 24.5 cm.ConclusionsThere was a significant relationship between the anterior superior iliac spine distance and the degree of acetabular dysplasia.

A pre‐operative approach of range of motion simulation and verification for femoroacetabular impingement

Femoroacetabular impingement (FAI) is increasingly recognized as a potential cause of hip osteoarthritis. A system capable of pre-operatively simulating hip range of motion (ROM) by given surface models from either healthy or FAI diseased bone is desirable. An impingement detection system using bounding sphere hierarchies was first developed. Both precision and accuracy of the impingement detection system were verified by a custom-designed phantom to imitate ball-and-socket hip movement. The impingement detection system was then implemented into the hip ROM simulation system to simulate the ROM of (1) healthy pelvis and femur, and (2) healthy pelvis and pathologic femur. The ROM simulation system was also verified by manipulating sawbones under the navigation of an optical tracking system. The impingement detection system achieved a distance error of 0.53 ± 0.06 mm and an angular error of 0.28 ± 0.03°. The impingement detection accuracies were 100%, 100%, and 96% in three different phantom orientations, respectively. The mean errors between simulated and verified ROM were 0.10 ± 1.39° for the 'healthy pelvis and femur' group, and - 2.38 ± 3.49° for the 'healthy pelvis and pathologic femur' group. The present study demonstrates a pre-operative approach to virtually simulate and predict the functional hip ROM based on the given bone models. The impingement detection and ROM simulation systems developed may also be used for other orthopedic applications.

Trends in Femoroacetabular Impingement Research over 11 Years

Femoroacetabular impingement is the abutment between the proximal femur and the rim of the acetabulum. It is a common cause of labral injury that has been identified as an early cause of hip osteoarthritis. The diagnosis of femoroacetabular impingement of the hip is currently well defined in orthopedic surgery but should attract the attention of physicians in other disciplines. Conversely, much less is known about the etiology and natural history of femoroacetabular impingement.The goal of this study was to assess the number of articles published on femoroacetabular impingement over 11 years in orthopedic vs nonorthopedic medical journals, and to evaluate the quality of available evidence. PubMed and OvidSP databases were searched for articles on femoroacetabular impingement published from 1999 to 2009. Articles were characterized by publication type and journal type per year. Regression analysis was used to determine the effect of publication year on number of publications of each type. The search yielded 206 publications on femoroacetabular impingement during the evaluation period. Seventy-two percent were published in orthopedic journals. Overall, the number of publications increased exponentially with time. There was an increase in clinical trials over the course of the study period. However, studies with high-quality evidence were scarce. The increase in data from orthopedic and nonorthopedic disciplines is welcome. Nevertheless, high-quality evidence on femoroacetabular impingement is lacking. We believe the current trend toward evidence-based orthopedic surgery will impact future research on this relatively new disorder.

Arthroplasty in Developmental Dysplasia of the Hip

Developmental dysplasia of the hip is a common cause of hip osteoarthritis. Although there have been many advances in surgical techniques of hip joint preservation, once symptomatic degenerative changes are present, arthroplasty or reconstructive procedures remain the main avenues of management. Arthroplasty in this group presents many significant reconstructive challenges in addition to concerns regarding implant survivorship in what is a typically relatively young cohort. In this article we review the many technical aspects of acetabular and femoral reconstruction and the outcomes and potential complications associated with arthroplasty in this group. Despite the complex nature of this surgery, appropriate techniques and implants are associated with excellent symptomatic relief and improved quality of life with acceptable survivorship for these patients.

Expert Opinion and Controversies in Musculoskeletal and Sports Medicine: Femoroacetabular Impingement

Standaert CJ, Manner PA, Herring SA. Expert opinion and controversies in musculoskeletal and sports medicine: femoroacetabular impingement. Femoroacetabular impingement (FAI) has been proposed as a distinct clinical entity that may be a potentially significant cause of hip osteoarthritis (OA). There is a growing body of literature on this condition, including descriptions of biomechanic mechanisms of impingement, anatomic and radiographic findings, and surgical interventions. Although a connection between anatomic abnormalities of the hip and the development of OA has been recognized for some time, there are limited data on the natural history of FAI and no long-term studies on the effect of surgical treatment. Thus, the diagnosis engenders a degree of controversy in multiple regards, including the diagnostic criteria and the role of operative intervention.