A comparison of three strategies to reduce the burden of osteoarthritis: A population-based microsimulation study.

OBJECTIVES: The purpose of this study was to compare three strategies for reducing population health burden of osteoarthritis (OA): improved pharmacological treatment of OA-related pain, improved access to joint replacement surgery, and prevention of OA by reducing obesity and overweight. METHODS: We applied a validated computer microsimulation model of OA in Canada. The model simulated a Canadian-representative open population aged 20 years and older. Variables in the model included demographics, body mass index, OA diagnosis, OA treatment, mortality, and health-related quality of life. Model parameters were derived from analyses of national surveys, population-based administrative data, a hospital-based cohort study, and the literature. We compared 8 what-if intervention scenarios in terms of disability-adjusted life years (DALYs) relative to base-case, over a wide range of time horizons. RESULTS: Reductions in DALYs depended on the type of intervention, magnitude of the intervention, and the time horizon. Medical interventions (a targeted increase in the use of painkillers) tended to produce effects quickly and were, therefore, most effective over a short time horizon (a decade). Surgical interventions (increased access to joint replacement) were most effective over a medium time horizon (two decades or longer). Preventive interventions required a substantial change in BMI to generate a significant impact, but produced more reduction in DALYs than treatment strategies over a very long time horizon (several decades). CONCLUSIONS: In this population-based modeling study we assessed the potential impact of three different burden reduction strategies in OA. Data generated by our model may help inform the implementation of strategies to reduce the burden of OA in Canada and elsewhere.

Implementation of the Good Life with osteoArthritis in Denmark (GLA:D) Program across Canada for the Management of Hip and Knee Osteoarthritis.

Good Life with osteoArthritis in Denmark (GLA:D®) is a program for the management of patients with hip and knee osteoarthritis (OA). Adapted for the Canadian population, the GLA:DTM Canada program implements evidence-based strategies to support the prevention, early diagnosis and effective management of hip and knee OA. GLA:D assists local communities in implementing OA strategies across the spectrum of disease severity. An integral part of this program is a national quality and outcomes registry, which includes data concerning participant characteristics and both patient-reported and functional outcomes. This registry helps healthcare providers and healthcare decision makers ensure that individuals with OA receive effective, high-quality care through the GLA:D Canada program.

Editorial Commentary: With Properly Indicated and Performed Surgery, We Can (Hopefully) Prevent Osteoarthritis in Patients With Hip Femoroacetabular Impingement.

Surgical treatment of femoroacetabular impingement (FAI) syndrome has been proven to be tremendously successful, outperforming the best conservative care and physical therapy in several prospective multicenter randomized controlled trials. The durability of this operation over time is less commonly reported on. We do know that FAI is associated with the development of hip osteoarthritis, and this is well established. We also know that surgical FAI treatment results in good short-term return to function/sport and improvements in patient-reported outcomes. We do not yet know if we are able to alter the natural history of FAI and prevent or delay conversion to total hip arthroplasty in this population.

Mecanismos etiopatogénicos de la artrosis / Ethiopathogenic mechanism of osteoarthritis

La artrosis es una enfermedad incurable que se caracteriza por un deterioro progresivo del cartílago articular asociado a una proliferación ósea subcondral y osteofitaria, que provoca dolor, limitación de la movilidad, discapacidad y deterioro de la calidad de vida del paciente. Existe una discrepancia clínica entre pacientes que radiológicamente están en un estadio similar.Se han descrito una serie de factores de riesgo que actuarían de forma sistémica o local en cada articulación. Estos factores, solos o de manera coincidente, darían lugar a las alteraciones estructurales de los tejidos articulares y desarrollarían la enfermedad. El mecanismo real por el cual estos factores de riesgo actúan no es del todo conocido. El conocimiento de su forma de actuar y el momento en que actúan sería una buena oportunidad para realizar un tratamiento específico y precoz que evite la aparición o la progresión de la artrosis.(AU)

Osteoarthritis is an incurable disease characterized by a progressive deterioration of the articular cartilage associated with a subchondral and osteophyte bone proliferation, which causes pain, limitation of mobility, disability, and deterioration of the patient's quality of life. There is a clinical discrepancy between patients who are radiologically in a similar stage.A series of risk factors have been described that would act systemically or locally in each joint. These factors alone or coincidentally would give rise to structural alterations of the joint tissues and would develop the disease. The actual mechanism by which these risk factors act is not entirely known. Knowing their way of acting and when they act would be a good opportunity to carry out a specific and early treatment that prevents the appearance or progression of osteoarthritis.(AU)

Is cup positioning easier in DDH patients previously treated with Bernese periacetabular osteotomy?

BACKGROUND: Acetabular orientation changes after periacetabular osteotomy (PAO) lead to technical change when performing subsequent total hip arthroplasty (THA). There is no unified consensus regarding the solution for acetabular component installation after PAO. In the current study, we performed computed tomography (CT)-based simulation of acetabular component installation and compared the acetabular defect and component position following THA after PAO and the same patient before PAO. METHODS: From January 2014 to December 2018, pelvic models of 28 patients (28 hips) underwent PAO and with the risk factors to develop secondary osteoarthritis. The acetabular reconstruction process was simulated using 3D models from CT data, and the acetabular component coverage was calculated in 3D space based on the measurement and algorithm we proposed. We evaluated the anterior, posterior, superior, inferior acetabular sector angle (ASA), the medial wall thickness (MWT), and the distance from the hip center to the plane of pubic symphysis and ossa sedentarium in the study group (post-PAO group) and control group (pre-PAO group). In addition, we investigated the changes in the acetabular component covering and size between the two groups. RESULTS: A-ASA and I-ASA values were significantly smaller in the post-PAO group than in the pre-PAO group. The S-ASA and distance values were significantly bigger in the post-PAO group. Compared to the pre-PAO group, the post-PAO group has a bone defect in the anterior and inferior medial. However, the post-PAO group has to elevate the cup to improved component coverings. CONCLUSION: Acetabular defection following simulation of cup installation after PAO was significantly changed compared to those without PAO. Elevation of hip joint centers as much as 4 mm and increase acetabular cup anteversion were therapeutic options for DDH patients following THA after PAO.

Periacetabular Osteotomy for Developmental Dysplasia of the Hip and Femoroacetabular Impingement: A Study Using the U.K. Non-Arthroplasty Hip Registry (NAHR) Data Set.

BACKGROUND: Periacetabular osteotomy (PAO) is a well-recognized procedure for the treatment of hip dysplasia in young adults and can be used for the surgical management of femoroacetabular impingement (FAI) with acetabular retroversion. The aim of this study was to use a national database to assess the outcomes of PAO for developmental dysplasia of the hip (DDH) and for FAI. METHODS: All patients in whom an isolated PAO had been performed between January 2012 and February 2019 were identified in the Non-Arthroplasty Hip Registry (NAHR). Their outcomes were assessed using the EuroQol-5 Dimensions (EQ-5D) index and the International Hip Outcome Tool (iHOT)-12 preoperatively and then at 6 months, 12 months, and 2 years postoperatively. RESULTS: Six hundred and thirty (630) PAOs were identified, with 558 (89%) performed for DDH and 72 (11%) performed for FAI. Most patients (90%) were female. The mean age in the DDH group (31.2 years) was significantly higher (p < 0.0001) than that in the FAI group (26.5 years). There were no other significant between-group demographic differences. Preoperatively and at each follow-up time-period, iHOT-12 scores were better in the DDH group than in the FAI group; however, only the preoperative scores differed significantly. There was significant improvement between the preoperative and 6-month iHOT-12 and EQ-5D index scores in both the DDH and the FAI group. This improvement was maintained at 12 months postoperatively, by which time almost 90% of the patients had achieved the minimum clinically important difference (MCID) in their iHOT-12 score. CONCLUSIONS: This study shows that PAO is a successful surgical intervention for DDH and FAI in the short term, with significant improvement in patient-reported outcome scores that is maintained up to 2 years postoperatively. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

To what extent is severe osteoarthritis preventable? Occupational and non-occupational risk factors for knee and hip osteoarthritis.

OBJECTIVES: To explore the relative contribution of cumulative physical workload, sociodemographic and lifestyle factors, as well as prior injury to hospitalization due to knee and hip OA. METHODS: We examined a nationally representative sample of persons aged 30-59 years, who participated in a comprehensive health examination (the Health 2000 Study). A total of 4642 participants were followed from mid-2000 to end-2015 for the first hospitalization due to knee or hip OA using the National Hospital Discharge Register. We examined the association of possible risk factors with the outcome using a competing risk regression model (death was treated as competing risk) and calculated population attributable fractions for statistically significant risk factors. RESULTS: Baseline age and BMI as well as injury were associated with the risk of first hospitalization due to knee and hip OA. Composite cumulative workload was associated with a dose-response pattern with hospitalizations due to knee OA and with hospitalizations due to hip OA at a younger age only. Altogether, prior injury, high BMI and intermediate to high composite cumulative workload accounted for 70% of hospitalizations due to knee OA. High BMI alone accounted for 61% and prior injury only for 6% of hospitalizations due to hip OA. CONCLUSION: Our results suggest that overweight/obesity, prior injury and cumulative physical workload are the most important modifiable risk factors that need to be targeted in the prevention of knee OA leading to hospitalization. A substantial proportion of hospitalizations due to hip OA can be reduced by controlling excess body weight.

Treatment for Post-Slipped Capital Femoral Epiphysis Deformity.

In situ pinning of slipped capital femoral epiphysis (SCFE) is a safe and effective treatment modality, but often results in residual deformity leading to femoroacetabular impingement, which may limit patient activities and predispose to early onset arthritis. Enhanced understanding of the implications of femoroacetabular impingement and new surgical techniques have prompted interest in treating post-slipped capital femoral epiphysis deformity to both improve current symptoms and delay or prevent hip arthrosis.

The two-year incidence of hip osteoarthritis after arthroscopic hip surgery for femoroacetabular impingement syndrome.

BACKGROUND: One of the reported goals of hip preservation surgery is to prevent or delay the onset of osteoarthritis. This includes arthroscopic surgery to manage Femoroacetabular Impingement (FAI) Syndrome. The purpose of this study was to describe the prevalence of clinically-diagnosed hip OA within 2 years after hip arthroscopy for FAI syndrome, and 2) determine which variables predict a clinical diagnosis of OA after arthroscopy. METHODS: Observational analysis of patients undergoing hip arthroscopy between 2004 and 2013, utilizing the Military Health System Data Repository. Individuals with prior cases of osteoarthritis were excluded. Presence of osteoarthritis was based on diagnostic codes rendered by a medical provider in patient medical records. Adjusted odds ratios (95% CI) for an osteoarthritis diagnosis were reported for relevant clinical and demographic variables. RESULTS: Of 1870 participants in this young cohort (mean age 32.2 years), 21.9% (N = 409) had a postoperative clinical diagnosis of hip osteoarthritis within 2 years. The 3 significant predictors in the final model were older age (OR = 1.04; 95%CI = 1.02, 1.05), male sex (OR = 1.31; 95%CI = 1.04, 1.65), and having undergone an additional hip surgery (OR = 2.33; 95% CI = 1.72, 3.16). Military status and post-surgical complications were not risk factors. CONCLUSION: A clinical diagnosis of hip osteoarthritis was found in approximately 22% of young patients undergoing hip arthroscopy in as little as 2 years. These rates may differ when using alternate criteria to define OA, such as radiographs, and likely underestimate the prevalence. A more comprehensive approach, considering various criteria to detect OA will likely be necessary to accurately identify the true rates. Females were at lower risk, while increasing age and multiple surgeries increased the risk for an OA diagnosis. OA onset still occurs after "hip preservation" surgery in a substantial number of individuals within 2 years. This should be considered when estimating rates of disease prevention after surgery. Prospective trials with sound methodology are needed to determine accurate rates and robust predictors of osteoarthritis onset after hip preservation surgery.

The Natural History of Lower Extremity Malalignment.

BACKGROUND: Lower extremity malalignment is a common problem presented to pediatric orthopaedists. Risk for early arthritis is often a concern among parents seeking advice and treatment. We seek to review previous research with regard to the natural history of malalignment. METHODS: A search of available literature on PubMed was constructed to capture articles covering the natural history of malalignment, secondary to childhood fracture as well as congenital and acquired pediatric deformity. In order to remain strictly relevant to pediatrics, articles reviewing deformities acquired in adulthood were not referenced. Biomechanical data and animal studies were included when deemed appropriate. RESULTS: High-quality data with regard to long-term risk of arthritis due to malalignment is lacking. Through a combination of biomechanical data, animal models, and a small body of longitudinal clinical data, it is clear that some patients with malalignment progress to early arthritic change. Unfortunately, detailed risk factors of who is at high risk versus low risk remains difficult to determine. CONCLUSIONS: Treatment of minor lower extremity malalignment is not supported by the current orthopaedic literature. Treatment plans should focus on the presence of symptoms, and in asymptomatic but severe cases. Even in more severe cases, strong evidence to support prophylactic realignment is not available. Evidence to suggest that preventative realignment is superior to intervention at the time of symptom onset does not exist.

Effect of contralateral cane use on hip moment impulse in the frontal plane during the stance phase.

BACKGROUND: Recent reports have shown that the daily cumulative moment in the frontal plane (i.e., product of hip moment impulse in the frontal plane during the stance phase and mean steps per day) is a risk factor for hip osteoarthritis. This study aimed to clarify the effect of contralateral cane use on hip moment impulse in the frontal plane of the stance limb. METHODS: This study included 15 healthy subjects who walked under four experimental conditions: (1) without a cane and (2-4) contralateral cane use with 10%, 15%, and 20% body weight support (BWS), respectively. To maintain the same walking speed in all conditions, the cadence was set to 80 steps/min, and the step length was fixed. The hip moment impulses in the frontal plane (i.e., area under the hip ab-adduction moment waveform) and peak hip adduction moments in all conditions were calculated. RESULTS: Contralateral cane use significantly decreased the hip moment impulse in the frontal plane and peak hip adduction moment compared to non-cane use. Moreover, the hip moment impulse in the frontal plane and peak hip adduction moment decreased significantly with increased cane BWS. There were no significant differences in walking speed, cadence, and step length between the four conditions. CONCLUSION: Contralateral cane use decreases the hip moment impulse in the frontal plane and peak hip adduction moment in the stance limb. These findings may help clarify how to delay the progression of hip osteoarthritis.

Gait abnormalities following slipped capital femoral epiphysis treated with in situ fixation.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is a common disorder in adolescent for which no consensus exists regarding management. The aim of the present study was to analyze gait modifications following SCFE treated with in situ fixation (ISF) and to relate it to radiologic stage. RESEARCH QUESTION: To verify if gait biomechanics are impaired in patients with SCFE and to try to determine a degree of slippage from which gait modifications would appear. METHODS: We evaluated 16 patients treated by ISF for SCFE with slippage ranging from 11° to 61°. Gait variables were compared to normal population according to age and walking speed and were normalized in Z-scores. RESULTS: Spatiotemporal parameters, mechanical and energetic variables were inferior to |1.5| Z-scores and considered as normal. Kinematics showed increase of pelvic tilt and hip adduction. Kinetic variables showed modifications with increased hip extension moment. There was also a strong increase in power of hip extensor. Hip extension moment and power of hip extensors were significantly correlated to radiologic stage. Analysis of ROC curves showed a cut-off value of slippage about 25°-30° affecting kinematics of pelvis and hip and kinetic variables. CONCLUSION: The gait variables were close to normal values. Main modifications were observed in kinematic and kinetic data with a significant increase in extension moment and power generated at the operated hip. This could participate to long-term joint degradation observed in SCFE, even in mild slips. The clinical message is to control regularly SCFE with initial slippage greater than >25-30° to allow for early diagnosis of premature hip osteoarthritis.

The Effects of Hip Mobilizations on Patient Outcomes: A Critically Appraised Topic.

Clinical Scenario: Hip osteoarthritis currently affects up to 28% of the population, and the number of affected Americans is expected to rise as the American population increases and ages. Limited hip range of motion (ROM) has been identified as a predisposing factor to hip osteoarthritis and limited patient function. Clinicians often apply therapy techniques, such as stretching and strengthening exercises, to improve hip ROM. Although traditional therapy has been recommended to improve hip ROM, the efficiency of the treatments within the literature is questionable due to lack of high-quality studies. More recently, clinicians have begun to utilize joint mobilization and the Mulligan Concept mobilization with movement techniques to increase ROM at the hip; however, there is a paucity of research on the lasting effects of mobilizations. Given the difficulties in improving ROM immediately (within a single treatment) and with long-lasting results (over the course of months), it is imperative to examine the evidence for the effectiveness of traditional therapy techniques and more novel manual therapy techniques. Focused Clinical Question: Is there evidence to suggest manual mobilizations techniques at the hip are effective at treating hip ROM limitations? Summary of Clinical Findings: 5 Randomized Controlled Studies, improved patient function and ROM with the Mulligan concept, high velocity low amplitude improved. Clinical Bottom Line: We found moderate evidence to suggest favorable outcomes following the use of hip mobilizations aimed at improving hip ROM and patient function. Strength of Recommendation: Strength of the studies identified are 1B.

Bernese periacetabular osteotomy through a double approach : Simplification of a surgical technique.

OBJECTIVE: Reorientation of the acetabulum to normalize load transfer or avert femoroacetabular pincer impingement to prevent osteoarthritis of the hip. INDICATIONS: Persisting acetabular dysplasia after closure of growth plates or acetabular malrotation. CONTRAINDICATIONS: High dislocation of hip, secondary acetabulum, increased misalignment on functional X­ray, high-grade mobility restriction. Relative: degenerative changes, advanced age. SURGICAL TECHNIQUE: Bernese periacetabular osteotomy through two incisions; all bone cuts are carried out under direct vision. The osteotomies are equivalent to the classic Ganz method. In a slightly tilted forward lateral decubitus position, a posterior incision is applied for the ischium osteotomy and the caudal portion of the retroacetabular osteotomy. The pubis and ilium osteotomies are performed in a supine position through an anterior approach with subsequent reorientation and screw fixation. The rectus femoris is not dissected unless joint exposure is required. POSTOPERATIVE MANAGEMENT: Partial weight bearing with 20 kg for the first 6 weeks postoperatively, followed by stepwise transition to full loads after radiological control. RESULTS: In total, 34 patients (37 hips) were followed up for 20.4 ± 10.3 months. Tönnis osteoarthritis scale levels remained constant. The center-edge angle of Wiberg increased from 13.2 ± 7.5° to 26.5 ± 6.7°, the Tönnis angle (acetabular index) changed from 13.8 ± 6.5° to 3.4 ± 4.4°. At follow-up, the Merle d'Aubigné and Postel score was 16.5 ± 1.4; the modified Harris hip score 87.6 ± 13.9 and the International hip outcome tool (iHOT)-12 78.2 ± 20.3 points. The mean surgical time was 213 ± 29 min. Severe complications were not observed.

Single Versus Combined Procedures for Severely Involved Legg-Calvé-Perthes Disease.

BACKGROUND: The concept of containment as an effective approach to reduce the risk of femoral head deformity has been questioned because modest results have been achieved after nonoperative and operative treatments for severely involved Legg-Calvé-Perthes disease. Several reports have shown the limited effectiveness of some conventional single procedures. However, there is limited data on the effectiveness of combined procedures. METHODS: The surgical group comprised 77 patients (mean age 8.3 y) and involved 79 hips. The average follow-up term was 9.5 years. Sixty-five patients were unilaterally involved and 12 patients were bilaterally involved (although 10 of the latter patients only received surgery on 1 hip). Among patients, 28 hips were classified as Herring class B/C border (>8 y old) and 51 hips were Herring class C. The 79 hips were divided into 2 treatment groups for further analysis: group 1, single procedures (femoral varus osteotomy) (n=47); group 2, combined procedures [femoral varus osteotomy+Dega (Pemberton) osteotomy] (n=32). RESULTS: Using Stulberg classification I and II (acceptable outcome), the final outcome was statistically significant for group 2 (21 hips, 65.6%) compared with group 1 (18 hips, 38.3%) (P=0.031). The average remodeling efficacy, defined as the change in caput index between preoperation and postoperation, was better in group 2 (12.7%) than in group 1 (3.9%) (P=0.005). The acetabulum-head index and α-angle were also statistically significant in group 2 than in group 1 at the last follow-up. Clinical evaluations were statistically significant in group 2 compared with group 1. CONCLUSIONS: Both clinically and radiologically, the combined procedure group demonstrated significantly better outcomes with accelerated remodeling in both the severely affected femoral heads and the acetabula compared with the single procedure group. With this procedure, we anticipate the increased likelihood of preventing or delaying coxarthroses in adulthood. LEVEL OF EVIDENCE: Level III-therapeutic study.

Delays in diagnosis are associated with poorer outcomes in adult hip dysplasia.

Background and Aims Developmental dysplasia of the hip is a common cause of osteoarthritis. Periacetabular osteotomy can restore femoral head coverage; however, it is reserved for patients with minimal articular degeneration. We examined the relationship between delays in diagnosis and outcomes. Methods We identified patients presenting to a hip specialist with a new diagnosis of hip dysplasia. The time taken between patients presenting to their general practitioner and attending the young adult hip clinic was established. Patients were stratified into Early, Moderate and Late Referral groups. Hip and SF-12 questionnaires were completed. Radiographs were graded according to the Tönnis classification system and the outcome following hip specialist review documented. Results Fifty-one patients were identified. Mean time from attending a general practitioner to review at the young adult hip clinic was 40.4 months. Lower hip and SF-12 scores, and higher radiological osteoarthritis grades were found in the Moderate and Late Referral groups. A higher proportion of the Moderate and Late Referral group underwent total hip arthroplasty rather than periacetabular osteotomy. Conclusion Delays in referring a patient to a hip specialist are associated with poorer outcomes. We propose pelvic radiographs are requested early by general practitioners to allow prompt diagnosis and referral to a hip specialist.

Changes in chondrolabral mechanics, coverage, and congruency following peri-acetabular osteotomy for treatment of acetabular retroversion: A patient-specific finite element study.

Using a validated finite element (FE) protocol, we quantified cartilage and labrum mechanics, congruency, and femoral coverage in five male patients before and after they were treated for acetabular retroversion with peri-acetabular osteotomy (PAO). Three-dimensional models of bone, cartilage, and labrum were generated from computed tomography (CT) arthrography images, acquired before and after PAO. Walking, stair-ascent, stair-descent, and rising from a chair were simulated. Cartilage and labrum contact stress, contact area, and femoral coverage were calculated overall and regionally. Mean congruency (average of local congruency values for FE nodes in contact) and peak congruency (most incongruent node in contact) were calculated overall and regionally. Load supported by the labrum was represented as a raw change in the ratio of the applied force transferred through the labrum and percent change following surgery (calculated overall only). Considering all activities, following PAO, mean acetabular cartilage contact stress increased medially, superiorly, and posteriorly; peak stress increased medially and posteriorly. Peak labrum stresses decreased overall and superiorly. Acetabular contact area decreased overall and laterally, and increased medially. Labral contact area decreased overall, but not regionally. Load to the labrum decreased. Femoral head coverage increased overall, anterolaterally, and posterolaterally, but decreased anteromedially. Mean congruency indicated the hip became less congruent overall, anteriorly, and posteriorly; peak congruency indicated a less congruent joint posteriorly. CLINICAL RELEVANCE: Medialization of contact and reductions in labral loading following PAO may prevent osteoarthritis, but this procedure increases cartilage stresses, decreases contact area, and makes the hip less congruent, which may overload cartilage. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2567-2576, 2017.

Bone Mineral Density and the Risk of Hip and Knee Osteoarthritis: The Johnston County Osteoarthritis Project.

OBJECTIVE: To address knowledge gaps regarding the relationship between bone mineral density (BMD) and incident hip or knee osteoarthritis (OA); specifically, lack of information regarding hip OA or symptomatic outcomes. METHODS: Using data (n = 1,474) from the Johnston County Osteoarthritis Project's first (1999-2004) and second (2005-2010) followup of participants ages ≥45 years, we examined the association between total hip BMD and both hip and knee OA. Total hip BMD was measured using dual x-ray absorptiometry, and participants were classified into sex-specific quartiles (low, intermediate low, intermediate high, and high). Radiographic OA (ROA) was defined as development of Kellgren/Lawrence grade ≥2. Symptomatic ROA (sROA) was defined as onset of both ROA and symptoms. Weibull regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs). RESULTS: Median followup time was 6.5 years (range 4.0-10.2 years). In multivariate models, and compared with participants with low BMD, those with intermediate high and high BMD were less likely to develop hip sROA (HR 0.52 [95% CI 0.31-0.86] and 0.56 [95% CI 0.31-0.86], respectively; P = 0.024 for trend); high BMD was not associated (HR 0.69 [95% CI 0.45-1.06]) with risk of hip ROA. Compared with participants with low BMD, those with intermediate low and intermediate high total hip BMD were more likely to develop knee sROA (HR 2.15 [95% CI 1.40-3.30] and 1.65 [95% CI 1.02-2.67], respectively; P = 0.325 for trend); similar associations were seen with knee ROA. CONCLUSION: Our findings suggest that higher BMD may reduce the risk of hip sROA, while intermediate levels may increase the risk of both knee sROA and ROA.

Comparison of femoral head translation following eccentric rotational acetabular osteotomy and rotational acetabular osteotomy.

PURPOSE: Eccentric rotational acetabular osteotomy (ERAO) is a modification of rotational acetabular osteotomy (RAO); it has been reported that ERAO allows the femoral head to translate medially and distally. However, no study has compared femoral head translation following RAO or ERAO. The purpose of this study was to compare immediate postoperative translation of the femoral head after RAO and ERAO in comparison with the preoperative position by radiological methods. METHODS: Patients treated by RAO or ERAO between 2006 and 2014 were retrospectively evaluated. 19 hips (17 patients) were treated with RAO, and 25 hips (22 patients) were treated with ERAO. The acetabular roof angle and the location of the femoral head were measured on anteroposterior pelvic radiographs. RESULTS: The mean preoperative acetabular roof angle was 20.9° in the RAO group and 22.0° in the ERAO group, showing no significant difference. The mean acetabular roof angle immediately postoperatively was -0.5° in the RAO group and -0.4° in the ERAO group, again showing no significant difference. The mean femoral head translation immediately postoperatively was 3.1 mm (95% confidence interval (CI), 1.5-4.7 mm) laterally and 3.0 mm (95% CI, 1.3-4.7 mm) proximally in the RAO group and 0.8 mm (95% CI, -0.7-2.3 mm) medially and 2.8 mm (95% CI, 1.5-4.1 mm) distally in the ERAO group; this difference was very highly significant (p<0.001). CONCLUSIONS: In contrast with RAO, ERAO resulted in significant femoral head translation both medially and distally immediately postoperatively.