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Purpose: Steroid-related osteonecrosis of the femoral head (ONFH), arising from steroid administration for underlying diseases, represents a unique pathology for total hip arthroplasty (THA) and typically affects a younger demographic compared to osteoarthritis (OA). Given the significant age-related differences, this study aims to employ propensity score matching to align patient backgrounds between these two diseases and compare physical function. Additionally, our objective is to scrutinize the patterns of clinical score recovery over the course of one year following THA., Methods: Using propensity score matching, 29 patients each with steroid-related ONFH and OA were selected. Muscle strength (hip abductor and knee extensor) were assessed before and after THA. Additionally, recovery of the Harris Hip Score (HHS) and Oxford Hip Score (OHS) up to one year postoperatively was analyzed., Results: The steroid-related ONFH group exhibited gender bias and significantly younger age compared to the OA group. Propensity score matching achieved balanced patient backgrounds. Physical function showed trends of lower hip abduction and knee extensor strength on the operative side in the steroid-related ONFH group. Notably, nonoperative knee extensor strength decreased significantly after matching. HHS and OHS were poor in steroid-related ONFH up to three months postoperatively but recovered after six months., Conclusions: Patients with steroid-related ONFH experience positive outcomes in clinical score following THA. Propensity score matching effectively identified muscle weakness on both operative and nonoperative sides, highlighting its utility in comparative analyses., (© 2024. The Author(s) under exclusive licence to SICOT aisbl.)

Objective: This study aimed to investigate the association between muscle density as an indicator of fatty infiltration of lower extremity muscles and physical activity (PA) after total hip arthroplasty (THA) and identify the patient characteristics with high postoperative PA., Methods: This study included 62 female patients who underwent THA for unilateral hip osteoarthritis. Muscle density of the gluteus maximus, gluteus medius, iliopsoas, and quadriceps muscles was measured using computed tomography (CT). PA was assessed using University of California, Los Angeles (UCLA) activity scores. CT and UCLA activity score were obtained before and 1 year after THA. The patients were divided into two groups, sufficient (score ≥ 6) and insufficient (score < 6) activity groups, based on their level of PA as determined by their UCLA activity score 1 year after THA. The association of PA with the amount of changes in muscle density was examined with Spearman's rank correlation coefficient. Logistic regression analysis was performed to identify postoperative factors determining PA at 1 year after THA., Results: Spearman's rank correlation coefficient showed a significantly positive association between recovery in PA and an increase in muscle density of the gluteus maximus, gluteus medius, iliopsoas, and quadriceps muscles. Additionally, logistic regression analysis confirmed that postoperative muscle densities of the gluteus maximus and quadriceps muscles were variables determining the PA 1 year after THA., Conclusion: The findings of this study indicated that the improvement of fatty infiltration in lower limb muscles, especially in the gluteus maximus and quadriceps, is likely to promote the increase in postoperative PA., (© 2023. The Author(s), under exclusive licence to International Skeletal Society (ISS).)

Introduction: Total hip arthroplasty (THA) can significantly improve quality of life (QOL) in patients with hip osteoarthritis. A relationship exists between activity levels and postoperative QOL, but its determinants are not well known. The aim of this work was to investigate the relationship between hip, pelvis and lumbar spine mobility and alignment before and after THA with QOL., Material and Methods: Consecutive patients with hip arthrosis and an indication for THA were included prospectively between July 2019 and December 2020, and they underwent lateral radiographs in free-standing, extension, relaxed- and flexed-seated position. Spinopelvic and hip parameters were measured, as well as their changes between positions to assess hip, pelvis and lumbar spine mobility. Patients were also administered QOL questionnaires. Data were collected preoperatively and 6 and 12 months postoperatively., Results: Seventy patients were included; QOL significantly increased 6 months after THA (from 18 [10; 27] to 61 [48; 72], p < 0.001). QOL further increased by 10 points or more after 6 months in 18% of patients, while it decreased in 16%. The latter showed higher pelvic range of motion (between flexion and extension) than the former., Conclusions: This study confirmed that QOL is significantly improved by THA, and that spinopelvic alignment and function can play a role. Future work should elucidate how to better predict postoperative QOL from preoperative patient characteristics to improve patient treatment and establish early postoperative physical therapy for patients who could benefit from postoperative improvement of activity-related QOL., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Many studies have demonstrated that low back pain (LBP) improves after total hip arthroplasty (THA). However, the mechanism underlying this improvement remains unclear. We aimed to investigate changes in the spinal parameters of patients who had LBP improvement after THA to elucidate the mechanism of LBP improvement., Methods: We included 261 patients who underwent primary THA between December 2015 and June 2021 and had a preoperative visual analog scale score of ≥ 2 for LBP. The patients were classified into the LBP-improved or LBP-continued groups based on the visual analog scale for LBP at 1 year after THA. Preoperative and postoperative changes in the coronal and sagittal spinal parameters were compared between the 2 groups after propensity score matching for age, sex, body mass index, and preoperative spinal parameters., Results: A total of 161 patients (61.7%) were classified into the LBP-improved group. After 85 patients in both groups were matched, the LBP-improved group showed significant differences in spinal parameter changes, which were a higher lumbar lordosis (LL) (P = .04) and lower sagittal vertical axis (SVA) (P = .02) and pelvic incidence (PI) minus LL (PI-LL) (P = .01) postoperatively, whereas the LBP-continued group showed worsened changes in LL and SVA and PI-LL mismatch., Conclusion: Patients who had LBP improvement after THA had significant differences in spinal parameter changes in LL, SVA, and PI-LL. These spinal parameters may be the key factors in the mechanism of LBP improvement after THA., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: To determine the reproducibility, criterion-related validity, and minimal clinically important difference (MCID) of the stair negotiation test (SNT) after total hip arthroplasty (THA)., Methods: Sixty patients who underwent THA were included in this study. They performed the SNT and rated their difficulty in stair negotiation (question 7 of the Oxford Hip Score [OHSQ7]) before and 6 months after surgery. The SNT determined the time taken by a patient to ascend, turn around, and descend the stairs (15 cm × 4 steps) and was measured twice each time. As a measure of reproducibility, the intraclass correlation coefficient (ICC 1,1 ) was calculated using the preoperative SNT. As an index of criterion-related validity, Spearman's rank correlation coefficient was used to evaluate the relationship between the better score of two trials in the preoperative SNT and the OHSQ7. The MCID of the SNT was calculated using the distribution-based method and the anchor-based method. The change in the OHSQ7 between before and after surgery was used as an anchor in the latter method., Results: The ICC 1,1 of the SNT was 0.97. The SNT was significantly correlated with the OHSQ7 (r = 0.40, p < .05). Moreover, the anchor-based MCID of the SNT was 1.98 seconds., Conclusion: The SNT is an objective assessable test of stair negotiation ability in post-THA patients that has good reproducibility and moderate criterion-related validity. Changes in the SNT beyond the MCID (1.98 seconds) represent clinically important changes in stair negotiation ability.

Introduction: In hip osteoarthritis, hip flexion contracture can severely alter the patient's alignment, and, therefore, affect the patient's quality of life (QOL). Hip contracture is not well-studied, partly because of the difficulties of its diagnosis. The aim of this study was to propose a quantitative definition of hip flexion contracture, and to analyse sagittal alignment in these patients compared to non-contracture ones, before and 12 months after total hip arthroplasty (THA)., Materials and Methods: Consecutive patients with hip arthrosis and an indication for THA were included (N = 123). Sagittal full-body radiographs were acquired in free standing position and in extension. QOL questionnaires were administered before and after surgery. Spinopelvic parameters were measured, including the pelvic-femur angle (PFA). Patients with low pelvic incidence (< 45°) were included in the hip contracture group if PFA > 5°, or PFA > -5° when pelvic incidence ≥ 45°., Results: 29% of patients were in the hip flexion contracture group, and they showed lower pelvic tilt than the no-contracture group (p < 0.001), larger lumbar lordosis (LL) and smaller PI-LL (p < 0.001), as well as a forward position of the head. 16% of patients still had hip contracture 12-months postop. Contracture patients showed higher QOL scores after surgery., Conclusions: The proposed method to diagnose hip contracture group allowed to define a group of patients who showed a specific pattern of sagittal spinopelvic alignment. These patients improved their alignment and quality of life postoperatively, but their hip mobility was not always restored. Diagnosing these patients is a first step toward the development of more specific surgical approaches, aiming to improve their surgical outcome., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Although introduction of minimally invasive techniques via anterolateral approaches considerably decreased prolonged limp after total hip arthroplasty (THA), potential damage to the abductor muscles is still a concern. This study aimed to evaluate the residual damage after primary THA with two types of anterolateral approach by assessing fatty infiltration and atrophy of the gluteus medius (GMed) and gluteus minimus (GMin) muscles., Methods: We retrospectively analyzed 100 primary THAs using computed tomography; surgeries were performed by detaching the anterior part of the abductor muscles with a bone fragment (anterolateral approach with trochanteric flip osteotomy) or without it (anterolateral approach without trochanteric flip osteotomy). The change in radiodensities (RDs), cross-sectional areas (CSAs), and clinical scores preoperatively and at 1 year after operation were evaluated., Results: The RD and CSA of GMed increased 1 year postoperatively in 86 and 81% of patients, respectively, while RD and CSA of GMin decreased in 71 and 94%, respectively. The improvement of RD of GMed was more frequently seen in the posterior rather than the anterior part, while the GMin decreased in both parts. The RD decrease of GMin was significantly lower in the anterolateral approach with trochanteric flip osteotomy group than the anterolateral approach without trochanteric flip osteotomy group (P = .0250). However, there was no difference in the clinical scores between the two groups. The change in the RD of GMed was the only factor that correlated with clinical scores., Conclusion: The two anterolateral approaches both improved the RD of GMed, recovery of which was significantly associated with postoperative clinical scores. Although the two approaches showed different recovery patterns in GMin until 1 year after THA, both showed similar improvements in clinical scores., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The purpose of this study is to investigate the relationship between gait and fat infiltration in anterior and posterior gluteus minimus in the patients with hip osteoarthritis., Methods: Ninety-one female patients who were diagnosed as the unilateral hip osteoarthritis, classified into Kellgren-Lawrence global scoring system grades 3 or 4, and candidate for total hip arthroplasty were retrospectively reviewed. The horizontally cross-sectional regions of interest for the gluteus medius and anterior and posterior gluteus minimus were manually circumscribed in a single transaxial computed tomography image and muscle density of those regions were obtained. The gait was assessed as the step and speed with the 10-Meter Walk Test. The multiple regression analysis was used to compare the step and speed with age, height, range of motion in flexion, the muscle density of anterior gluteus minimus in the affected side, and that of gluteus medius muscle in both affected and unaffected sides., Findings: Multiple regression analysis for step revealed that the muscle density of anterior gluteus minimus in the affected side and height were the independent predictors for step (R 2  = 0.389, p < 0.001). That for speed identified the muscle density of anterior gluteus minimus in the affected side as the only factor determining speed (R 2  = 0.287, p < 0.001)., Interpretation: The fatty infiltration of anterior gluteus minimus muscle in affected side can be a predictor for the gait in in female with unilateral hip osteoarthritis and candidates for total hip arthroplasty., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Cementless glass ceramics containing apatite and wollastonite (AW-GC) bottom-coated titanium hip implants were developed; early excellent clinical and radiographic results have been reported previously. This study aimed to investigate the long-term clinical and radiographic outcomes in detail, and the wear rate of HXLPE., Methods: We retrospectively evaluated 99 patients (117 hips) between November 2001 and December 2007. The survival rate was estimated using the Kaplan-Meier method. Hip joint function was evaluated using the Japanese Orthopaedic Association (JOA) score. The extent of radiographic signs was determined from the radiographs performed at the last follow-up. Polyethylene wear was measured using Martell's Hip Analysis Suite. We assessed the possible factors affecting the steady-state linear wear rate., Results: The mean follow-up period was 14.8 ± 2.1 (10-18.6) years. The mean JOA score improved to 88.7 ± 9.4 (59-100) at the final follow-up from 47.8 ± 12.5 (17-76) before surgery. The overall survival rate with the end point of all-cause revision and wear-related revision was 99% and 100% respectively. There was no osteolysis or loosening of either the acetabular or femoral component. All hips were classified as having bone ingrowth fixation. The mean steady-state wear rate was 0.008 ± 0.025 mm/year. We found no significant correlation between the wear rate and age, body weight, body mass index, cup inclination and femoral head size., Conclusion: The combination of AW-GC bottom-coated implants and HXLPE showed excellent implant survival and wear resistance for 15 years., Competing Interests: Declaration of competing interest Shuichi Matsuda received grants or contracts from Kyocera and Smith & Nephew, consulting fees from Kyocera, and honoraria from Kyocera and Zimmer Biomet., (Copyright © 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Introduction: Hip-spine syndrome, wherein flexion deformity of the hip might exaggerate normal lumbar lordosis (LL), was first described in 1983. It could result in subluxation of the posterior facets and cause low back pain (LBP). However, the clinical outcomes of total hip arthroplasty (THA) and spinal alignment changes in patients with lumbar hyperlordosis (hyper LL) remain unknown. We aimed to clarify the proportion of patients with hyper LL before THA and compare pre- and post-operative sagittal spinal alignment, LBP, and clinical outcomes between patients with hyper LL and those with normal LL., Materials and Methods: We investigated 278 patients who underwent primary THA between December 2015 and December 2019. Spine radiographs in the standing position were examined preoperatively and 1 year postoperatively. Patients with hyper LL were defined as having a pelvic incidence (PI) minus LL of < - 9° preoperatively. The control group included age- and sex-matched patients with normal LL, defined by a PI minus LL of - 9° to 9°. Clinical outcomes were evaluated using the visual analogue scale (VAS) for LBP, Harris hip score (HHS), Oxford hip score (OHS), and University of California, Los Angeles (UCLA) activity score., Results: Thirty-eight patients (13.7%) had hyper LL, and they exhibited a lower pelvic tilt, lower sagittal vertical axis, and greater sigmoid curvature than did the controls. Evaluation of changes in the spinal alignment after surgery showed that the pelvis tilted more posteriorly, and LL decreased more in the hyper LL group than in the control group. Pre- and post-operative VAS for LBP, HHS, OHS, and UCLA activity scores were not significantly different between the two groups., Conclusion: Hyper LL in patients with hip osteoarthritis had no adverse effects on LBP and the clinical outcomes of THA. Hyper LL may partially result from a flexible and adaptable lumbo-pelvic structure., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To develop clinical prediction rule (CPR) of physical activity 1 year after total hip arthroplasty (THA)., Design: Retrospective cohort study., Setting: University hospital with orthopedic surgery., Participants: The study group included 321 patients (56 men) who underwent primary THA (N=321)., Intervention: Not applicable., Main Outcomes Measures: The data collected included age, body mass index, clinical score from the questionnaires, hip pain, range of motion, muscle strength, and Physical functions (10-meter walk test [10MWT], timed Up and Go test, sit-to-stand test). Patients were classified into sufficient and insufficient activity groups based on their University of California, Los Angeles (UCLA) activity score 1 year after THA. Variables measured preoperatively and 3 weeks postoperatively were analyzed using univariate and multivariate methods to derive CPR for physical activity., Results: A CPR was developed using the following 5 factors and cutoffs: age 70.5 years or younger, preoperative UCLA activity score ≥3.5, preoperative hip abduction strength ≥0.54 Nm/kg, preoperative knee extension strength ≥1.04 Nm/kg, and 10MWT ≤8.49 seconds 3 weeks after surgery. The presence of 4 of the 5 factors predicted a sufficient physical activity level at 1 year, with a positive likelihood ratio of 5.94 and probability of 85.4%. The presence of 5 predictor variables increased the probability of sufficient physical activity after THA to 94.7%., Conclusions: This study developed a CPR for physical activity 1 year after THA. Having 4 or more of the 5 measurements were useful indicators for predicting of physical activity 1 year postoperatively., (Copyright © 2022 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Introduction: The surface topography is one key factor that affects the initial fixation of prosthesis in total hip arthroplasty (THA). We aimed to evaluate the mid-term results of a Zweymüller-type noncemented femoral implant (Elance stem) that had a matte surface with a target average roughness of 1.0 to 2.5 μm. The prosthesis was subjected to alkali and heat treatments to enhance its bone-bonding property., Methods: In this retrospective study, 30 THAs (27 patients) done using an Elance stem from September 2012 to October 2014 were evaluated clinically and radiographically for a mean follow-up of 6.3 ± 1.7 years after the index THA., Results: Stem revision was indicated for six hips (20%). The survival rate with stem revision for any reason was 86.4% (95% confidence interval, 68.9%-94.8%) at 5 years. Stem subsidence >5 mm was noted in 17 hips (56.7%). The survival rate with stem subsidence >5 mm as the end point was 46.6% (95% confidence interval, 29.9%-64.2%) at 5 years., Conclusion: The Zweymüller-type noncemented stem with a low-roughness matte surface demonstrated a high subsidence rate, although the bone-bonding property was potentially enhanced by the alkali and heat treatments. Surgeons should be aware that an insufficient surface roughness could lead to poor mechanical fixation of the noncemented stem, even with an appropriate stem geometry and surface chemistry., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Purpose: This retrospective study aimed to evaluate the benefits of closed suction drainage (CSD) in hybrid total hip arthroplasty (THA) with intra-articular administration of tranexamic acid (TXA)., Methods: We included 369 hips that underwent primary hybrid THA between November 2015 and September 2020. We compared peri-operative blood test results, blood loss, and post-operative complications including transfusion, wound complications, and venous thromboembolism (VTE) with or without CSD. Propensity score matching was performed to balance baseline patient demographics., Results: Transfusion, wound complications, and VTE were observed in 1.9% (seven), 2.4% (nine), and 2.2% (eight) of hips, respectively. There were no significant differences in transfusion, blood loss, wound complications, and deep venous thrombosis in both overall patients and propensity score-matched patients with or without CSD. The calculated total blood loss was approximately 600 ml and showed no significant difference between the two groups in the matched cohort (p = 0.59)., Conclusion: CSD does not provide any benefits and is not needed in primary hybrid THA with intra-articular administration of TXA., (© 2022. The Author(s) under exclusive licence to SICOT aisbl.)

Aims: The relationship between prosthetic position and range of motion (ROM) after total hip arthroplasty (THA) has been rigorously examined. However, the effects of limb lengthening on postoperative hip ROM remain unclarified. We aimed to examine the effect of limb lengthening on hip ROM after THA., Methods: We retrospectively reviewed the data from 120 patients who underwent unilateral THA. Univariate and multivariate regression models were used to evaluate the effects of the following patient- and surgery-related covariates on hip flexion ROM at 3, 6, and 12 months after THA: age, sex, body mass index, diagnosis, preoperative University of California Los Angeles activity score, preoperative Oxford Hip Score, preoperative flexion ROM, amount of leg lengthening, cup inclination, and cup anteversion., Results: A large preoperative hip flexion ROM was the strongest predictor of a large hip flexion ROM at 12 months after THA (standardized coefficient: 0.519, P < 0.0001). A larger amount of leg lengthening was associated with a smaller postoperative hip flexion ROM (standardized coefficient: -0.159, P = 0.039), and male sex was another predictor of a smaller postoperative hip flexion ROM (standardized coefficient: -0.204, P = 0.014). Cup inclination (P = 0.99) and anteversion (P = 0.18) were not significantly associated with hip flexion ROM at 12 months after THA., Discussion: A large amount of limb lengthening was associated with decreased hip flexion ROM after THA. In THA, minimizing the leg length discrepancy is important; however, the postoperative improvement in hip flexion ROM may be limited when a large amount of leg lengthening is needed., (Copyright © 2022 by the American Academy of Orthopaedic Surgeons.)

Background: Corticosteroids are essential for immunosuppression after orthotopic liver transplantation (OLT), but also have many side effects. Osteonecrosis of the femoral head (ONFH) is one of the most serious complications requiring prostheses. However, few studies have investigated ONFH after OLT. The purpose of this study is to survey the incidence of corticosteroid-induced ONFH after OLT and the outcomes of total hip arthroplasty (THA)., Methods: Between January 2001 and December 2010, a series of 926 patients underwent OLT at our Hospital. A retrospective analysis was performed on a total of 738 patients who survived at least 2 years after OLT. The incidence of symptomatic ONFH, the interval from OLT to the initial diagnosis of ONFH, and the cumulative dose of corticosteroids were analyzed. The side effects related to OLT, such as other osteonecrosis lesions, osteoporotic fractures, and infection, were monitored. For patients who underwent THA, radiological findings and Japanese Orthopaedic Association (JOA) scores were evaluated., Results: ONFH occurred in 10 patients (13 hips) (6 men [7 hips], 4 women [6 hips]), with an incidence of 1.36%. The average age at OLT was 51.4 years (range, 31-61 years). The average interval from OLT to ONFH was 86.7 months (range, 22-155 months). The average cumulative dose of corticosteroids was 7274 mg (range, 1342-29,514 mg). Twenty patients suffered from side effects related to OLT. Seven patients (8 hips) underwent THA. No adverse events including infection arose during the perioperative process. One hip dislocated, and one femoral stem displayed a radiolucent line. The average JOA score improved from 45.4 (range, 25-76) preoperatively to 86.9 (range, 73-99) at final follow-up. No patients required revision surgery., Conclusions: The incidence of symptomatic ONFH after OLT was 1.36%. Once the graft function becomes stable, THA can be a safe and effective treatment option for patients with ONFH after OLT., Competing Interests: Conflicts of interest The authors have no conflicts of interest to disclose., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Polyethylene wear is one of the major concerns of orthopedic surgeons. However, there is no standardized calculation method for the wear rate following radiographic measurement. The purpose of this study was to propose a novel method of wear calculation and to compare its accuracy with a representative conventional method., Methods: Relative position of the center of the femoral head to that of the cup progresses in one direction following arthroplasty surgery because of bedding-in and wear. We predetermined the amount of bedding-in, wear rate, and random error in measuring the head center position in a 2-dimensional plane. We calculated the wear rate using the head center coordinates over a certain number of measurement periods using a representative conventional method and our novel method. The conventional method consisted of transforming vector data into scalars and conducting a least-squares method. The least-squares method was directly applied to each component of the vector in the novel method. We evaluated the accuracy of these methods by comparing the expected value for the wear rate with their predetermined true values., Results: If the error were limited to being random, the novel method could provide the predetermined wear rate as the calculation result. However, the conventional method could not., Conclusion: We recommend using the novel method for the wear calculation rather than the conventional method because of its mathematical accuracy., (© 2022. The Author(s).)

Aims: The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA)., Methods: We retrospectively evaluated 29 patients (35 hips) who underwent THA between December 2000 and February 2002. The survival rate was estimated using the Kaplan-Meier method. Hip joint function was evaluated using the Japanese Orthopaedic Association (JOA) score. Two-dimensional polyethylene wear was estimated using Martell's Hip Analysis Suite. We calculated the wear rates between years 1 and 5, 5 and 10, 10 and 15, and 15 and final follow-up., Results: The mean follow-up period was 19.1 years (SD 0.6; 17.3 to 20.1). The 19-year overall survival rate with the end point of all-cause revision was 97.0% (95% confidence interval (CI) 91 to 100). The mean JOA score improved from 43.2 (SD 10.6; 30 to 76) before surgery to 90.2 (SD 6.4; 76 to 98) at the final follow-up (p < 0.001). There was no osteolysis or loosening of the acetabular or femoral components. The overall steady-state wear rate was 0.013 mm/year (SD 0.012). There was no hip with a steady-state wear rate of > 0.1 mm/year. There was no significant difference in wear rates for each period. We found no significant correlation between the wear rate and age, body weight, BMI, or cup inclination., Conclusion: First-generation annealed HXLPE shows excellent wear resistance and no acceleration of wear for approximately 20 years, with low all-cause revision rates. Cite this article: Bone Joint J  2022;104-B(2):200-205.

Introduction: Hip osteoarthritis (OA) with acetabular dysplasia negatively affects pelvic alignment and muscle function. We aimed to investigate the changes in muscle atrophy and fatty infiltration of the hip and trunk muscles 1 year after total hip arthroplasty (THA) in patients with hip OA with acetabular dysplasia., Methods: This study included 51 female patients who underwent THA for unilateral hip OA with acetabular dysplasia. The cross-sectional area (CSA) and muscle density of the gluteus maximus, gluteus medius, gluteus minimus, piriformis, iliopsoas, rectus abdominis, and abdominal oblique muscles using computer tomography and pelvic inclination angle using radiographs were assessed before and 1 year after THA., Results: At the 1-year follow-up, the CSA and muscle density of the gluteus medius (2,078 to 2,522 mm2 and 30.3 to 39.4 hounsfield units [HU]), iliopsoas (715 to 901 mm2 and 40.3 to 50.8 HU), and rectus abdominis (336 to 363 mm2 and 28.6 to 30.6 HU) of the affected limb had increased significantly (P < 0.05). The CSA and muscle density of the gluteus maximus (2,429 versus 2,884 mm2 and 23.7 versus 32.6 HU), gluteus minimus (636 versus 785 mm2 and 14.3 versus 37.1 HU), piriformis (505 versus 607 mm2 and 23.4 versus 31.6 HU), and iliopsoas (901 versus 997 mm2 and 50.8 versus 54.5 HU) in the affected limb were lower than those in the unaffected limb (P < 0.01). Postoperatively, the CSA and muscle density of the rectus abdominis were not significantly different between the limbs, and the pelvic inclination angle (35.2° to 32.1°, P < 0.01) was significantly decreased., Discussion: Compared with the nonoperated limb, substantial atrophy and fatty infiltration of most hip muscles persisted in the operated limb 1 year after THA in patients with acetabular dysplasia; asymmetry in the rectus abdominis muscle fully resolved. In patients with acetabular dysplasia, the surgical technique and postoperative rehabilitation should be further considered to optimize hip muscle recovery., (Copyright © 2021 by the American Academy of Orthopaedic Surgeons.)

Background: Spinal disorders and low back pain (LBP) have been associated with worse clinical outcomes of total hip arthroplasty (THA). It is essential to identify spinal factors associated with post-THA LBP improvement. Therefore, we aimed to determine the proportion of patients with improved LBP after THA and to identify the preoperative spinal factors associated with LBP improvement., Methods: We included 151 patients who underwent primary THA between December 2015 and December 2019 and had a preoperative visual analog scale score for LBP of ≥2. The patients were classified into the LBP improved or LBP continued group based on a visual analog scale score for LBP at 1 year after THA. Preoperative spinal parameters were compared between the 2 groups., Results: Ninety-five patients (62.9%) were classified into the LBP improved group. Among the coronal spinal parameters, the Cobb angle was significantly lower in the LBP improved group. Among the sagittal spinal parameters, the LBP continued group showed a significantly more posteriorly titled pelvis, lower lumbar lordosis, greater sagittal vertical axis, and greater pelvic incidence minus lumbar lordosis mismatch, indicating a sagittal spinal imbalance. Logistic regression analysis found that preoperative factors associated with LBP improvement after THA had a low Cobb angle and high anterior pelvic plane angle (anteriorly tilted pelvis)., Conclusion: Among patients with LBP before THA, 62.9% had improved LBP. Sagittal spinal imbalance and high Cobb angle were the key spinal factors associated with persistent LBP. Our findings suggest that hip surgeons should evaluate spinal alignment before THA in patients with LBP., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Aims: We aimed to evaluate the long-term outcome of highly cross-linked polyethylene (HXLPE) cemented acetabular components and assess whether any radiolucent lines (RLLs) which arose were progressive., Methods: We retrospectively reviewed 170 patients who underwent 187 total hip arthroplasties at two hospitals with a minimum follow-up of ten years. All interventions were performed using the same combination of HXLPE cemented acetabular components with femoral stems made of titanium alloy. Kaplan-Meier survival analysis was performed for the primary endpoint of acetabular component revision surgery for any reason and secondary endpoint of the appearance of RLLs. RLLs that had appeared once were observed over time. We statistically assessed potential relationships between RLLs and a number of factors, including the technique of femoral head autografting and the Japanese Orthopaedic Association score., Results: The mean follow-up period was 13.0 years (10.0 to 16.3). Femoral head autografting was performed on 135 hips (72.2%). One acetabular component was retrieved because of deep infection. No revision was performed for the aseptic acetabular loosening. The Kaplan-Meier survival curve for the primary and secondary endpoints were 98.2% (95% confidence interval (CI) 88.6% to 99.8%) and 79.3% (95% CI 72.8% to 84.6%), respectively. RLLs were detected in 38 hips (21.2%), at a mean of 1.7 years (1 month to 6 years) postoperatively. None of the RLLs were progressive, and the presence of RLLs did not show a significant association with the survival and clinical score. RLLs were more frequently observed in hips without femoral head autografts than in those with autografts., Conclusion: The use of HXLPE cemented acetabular components in total hip arthroplasty demonstrated excellent clinical outcomes after ten years, and no RLLs were progressive, and their presence did not affect the outcome. Femoral head autografting did not negatively impact the acetabular component survival or the appearance of RLLs. Cite this article: Bone Joint J  2021;103-B(10):1604-1610.

Aim: This study aimed to evaluate the 2-year outcomes from a clinical trial of recombinant human FGF-2 (rhFGF-2) for osteonecrosis of the femoral head (ONFH). Patients & methods: Sixty-four patients with nontraumatic, precollapse and large ONFHs were percutaneously administered with 800 μg rhFGF-2 contained in gelatin hydrogel. Setting the end point of radiological collapse, we analyzed the joint preservation period of the historical control. Changes in two validated clinical scores, bone regeneration and safety were evaluated. Results: Radiological joint preservation time was significantly higher in the rhFGF-2 group than in the control group. The ONFHs tended to improve to smaller ONFHs. The postoperative clinical scores significantly improved. Thirteen serious adverse events showed recovery. Conclusion: rhFGF-2 treatment increases joint preservation time with clinical efficacy, radiological bone regeneration and safety.

For patients with non-traumatic osteonecrosis of the femoral head (ONFH), core decompression (CD) and bone grafts (BG) are mainly performed in the West, while osteotomy is found to be predominant in Japan. It is not well recognized how the surgical procedures for joint preservation in patients with ONFH are completely different between the United States and Japan. This paper identifies the contexts and the differences in treatment strategies for ONFH between the two countries. We compared the surgical trends of the two countries over three periods, 1997-2001, 2002-2006, and 2007-2011 (the US data for the third period was 2007-2008), based on a 2014 US paper and a 2013 national publication in Japan. We compared the details of surgery for non-traumatic ONFH under the same conditions in the two reports. For the period 1997-2001, the rates of surgeries for ONFH in the US were as follows: total hip arthroplasty (THA), 86%; CD, 10%; and osteotomy, 0.4%. In Japan, THA was 61%, osteotomy 38%, and CD 0%. For the recent period, 2007-2011 (US 2007-2008), the rate of THA was 91%, CD 6%, and osteotomy 0.1%, in the US, compared to a THA rate of 73%, CD 0%, and osteotomy 26% in Japan. The results for the interim period (2002-2006) were between the old and new data. The use of joint-preserving surgery for ONFH differs greatly between the US and Japan. The first-line joint-preserving surgery was CD in the US and osteotomy in Japan. Each procedure was rarely done in the other country. From about 2000 to 2010, the percentage of THA increased in both countries. The proportion of joint-preserving surgery (CD in the US and osteotomy in Japan) declined. The decrease in joint-preserving procedures may be largely attributed to improved long-term outcomes of THA due to technological advances. There is also a reluctance for young ONFH patients to undergo joint-preserving procedures, such as osteotomy, that require long-term hospitalization., (© 2021 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Case: We report 2 patients who developed chronic expanding hematomas (CEHs) more than 20 years after ceramic-on-polyethylene total hip arthroplasty (THA). One CEH occurred after a minor fall, and the other appeared with no obvious injury. Neither of the 2 was on anticoagulation. Each caused extensive osteolysis., Conclusion: The only 2 previously reported post-THA cases of CEH involved metal-on-metal THAs and occurred several years after the index THA. Our patients show that CEH also can occur after ceramic-on-polyethylene THA, even after an uneventful clinical course of more than 20 years. Complete removal of both hematoma stopped osteolytic progression, with no recurrence to date., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B369)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Background: Half of osteonecrosis of the femoral head (ONFH) patients suffer femoral head collapse at initial diagnosis, and more than half are bilaterally affected. This study developed a percutaneous autologous impaction bone graft (IBG) technique as a modification of core decompression (CD). We also summarized the short-term results and treatment efficacy of percutaneous autologous IBG in advanced ONFH., Methods: Twenty patients (12 males, 8 females) with nontraumatic, postcollapse ONFH except one case underwent CD (10-mm core diameter) and reverse IBG. Radiological changes of the ONFH stage and type were analyzed. Survival analysis using Kaplan-Meier estimates was performed with conversion to total hip arthroplasty (THA) as the endpoint. In addition, the Harris hip score (HHS) and University of California, Los Angeles (UCLA) activity rating scale were evaluated., Results: Percutaneous autologous IBG was performed successfully, with an average operation time of < 1 h and small blood loss, and 7 patients (35%) needed conversion to THA at an average of 17 months postoperatively. We observed radiological progressive change in 60% of the patients during a mean observation period of 3 years. The mean clinical scores, except data recorded, after THA significantly improved (before vs. after 3 years: UCLA activity score, 3.7 vs. 5.2 [P = 0.014]; HHS, 57.6 vs. 76.5 points [P = 0.005]). In addition, 6 patients showed radiological progression but no clinical deterioration., Conclusions: Percutaneous autologous IBG was technically simple and minimally invasive, but short-term results were unsatisfactory for advanced ONFH. Indications for this procedure should be carefully examined to improve it in order to enable bone formation.

Background: The etiology of sacroiliac joint (SIJ) degeneration has not been fully elucidated, and there has been almost no report on the relevance between SIJ degeneration and hip osteoarthritis secondary to developmental dysplasia of the hip (DDH). We investigated factors associated with SIJ degeneration, specifically its laterality in patients with end-stage hip osteoarthritis secondary to unilateral DDH., Methods: We included 152 patients with end-stage unilateral hip osteoarthritis secondary to DDH who underwent primary THA between January 2008 and November 2015. SIJ degeneration was classified (type 0, no degenerative change, to type 3, ankyloses) using preoperative axial computed tomography. SIJ degeneration of the DDH (shorter leg) and contralateral (longer leg) sides was compared; differences in patient demographics and radiological parameters between SIJ degeneration of type 0 or 1 versus type 2 or 3 for the shorter and longer leg sides were analyzed., Results: SIJ on the longer leg side showed more degenerative changes (p < 0.001). Substantial SIJ degeneration or ankylosis (type 2 or 3) was observed on 62.5% of longer leg sides and 33.6% of shorter leg sides. Factors significantly associated with SIJ degeneration severity were percent hip subluxation and leg length discrepancy for the longer leg side and body weight and body mass index (BMI) for the shorter leg side. Patients with worse degeneration on the shorter leg side (9.9%) had significantly larger BMI and longer sagittal vertical axis, whereas patients with worse degeneration on the longer leg side (46.7%) had significantly longer leg length discrepancy., Conclusion: Severe SIJ degeneration was common in patients with end-stage hip osteoarthritis secondary to unilateral DDH. Patients with worse SIJ degeneration on the longer leg side had more hip subluxation, whereas patients with worse SIJ degeneration on the shorter leg (DDH) side tended to have sagittal spinal imbalance and greater body weight with larger BMI., Competing Interests: Declaration of Competing Interest This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2020 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Objective: The aim of this study was to identify which aspect of the preoperative lower limb functions is most likely to affect the functional mobility at 6 mos after total hip arthroplasty., Design: The study subjects included 125 women who underwent total hip arthroplasty. Hip flexion and abduction angles, hip abductor and knee extensor strengths, and lower limb load were measured preoperatively. The Timed Up and Go test was performed 6 mos postoperatively. Then, patients were divided into fast or slow groups as per the comparison with the Timed Up and Go score of healthy women., Results: Hip abductor strength and lower limb load on the nonoperative side were revealed as significant measurements that affected functional mobility after total hip arthroplasty according to stepwise multiple logistic regression analysis. Moreover, receiver operating characteristic curve analyses showed that the postoperative functional mobility was predicted by the lower limb load of the nonoperative side (cutoff point, 8.97 N/kg; sensitivity, 62.3%; specificity, 82.8%; and area under the curve, 77.5%)., Conclusions: This study revealed that patients with preoperative hip abductor strength of greater than 0.66 Nm/kg and lower limb load of greater than 8.97 N/kg on the nonoperative side could achieve better functional mobility at 6 mos postoperatively than healthy women of the same age group., Competing Interests: Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Background: We report on the outcomes of a double-tapered cemented stem made of β-titanium alloys (Ti-15Mo-5Zr-3Al) at least 10 years after total hip arthroplasty., Methods: We retrospectively analyzed 148 consecutive, primary total hip arthroplasties using this stem performed in 130 patients between January 2004 and August 2008. The patients' mean age was 59.6 years (range, 24-79). Implant survival was evaluated using Kaplan-Meier curves with the primary end point being stem revision for any reason and the secondary end point being stem revision for aseptic stem loosening. We also clinically and radiologically followed 140 hips (in 123 patients) for an average of 12.2 years (range, 10-15)., Results: The only revisions were for 2 stems with deep infection. Ten-year survival was 99.3% (95% confidence interval, 95.4%-99.9%) and 100% for the primary and secondary end point, respectively. The mean Japanese Orthopaedic Association hip score improved from 51.4 preoperatively to 88.7 at the last follow-up. Radiolucent lines at the stem-cement interface were seen in 14 hips (10.0%). None of the hips met the criteria of radiological stem loosening. Nineteen stems (13.6%) subsided by around 1 mm between 2 and 8 years after surgery. Distal femoral cortical hypertrophy occurred in 24 hips (17.0%), mostly with valgus alignment., Conclusion: The clinical outcomes of the femoral stems were excellent with survival at 10 years. Stem subsidence and distal femoral cortical hypertrophy did not affect the results. Long-term use of β-titanium alloy stems is safe and effective., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Total hip arthroplasty (THA) with subtrochanteric shortening osteotomy for Crowe type IV hips poses the risk of nonunion at the osteotomy site. The aim of this study was to analyze the factors that affect the bone union rate at the osteotomy site., Methods: We retrospectively reviewed a consecutive series of 27 THAs with subtrochanteric transverse shortening osteotomy performed for Crowe type IV hips. The effects of patient-related and surgery-related factors on the risk of delayed union were analyzed using univariate and multivariate regression analyses., Results: The mean follow-up period was 10.0 (1.4 to 19.1) years. The implant survival rate was 87.8% (95% confidence interval: 60.2% to 97.2%) at 10 years. The length of femoral bone resection was the only factor associated with the risk of delayed union. Longer bone resection lengths were significantly correlated with the reduced risk of delayed union (odds ratio: 0.63 [0.030 to 0.90], P = 0.0013). Other variables, including the use of a cement stem (P = 0.34) and the presence of a gap >1 mm at the osteotomy site (P = 0.98), were not associated with the risk of delayed union., Discussion: THA with subtrochanteric transverse osteotomy provides satisfactory long-term results for Crowe type IV hips. For shorter required femoral resection lengths, the risk of delayed union was higher. A longer resection could permit fabrication of longer autologous longitudinal bone struts and likely contributes to enhanced stability at the osteotomy site.

Background: Regional clinical pathways, a new type of clinical pathway, are practiced with the aim of standardizing and optimizing medical care by cooperation among multiple medical institutions in a region. However, current evaluation of the effectiveness of regional clinical pathways for hip fracture, a major health problem requiring hospitalization for orthopedic surgery, is insufficient. This study aimed to determine the association between regional clinical pathways and postoperative hospital length of stay (LOS) among hip fracture patients. In particular, we focused on the variation in postoperative LOS of hip fracture patients among hospitals and the contribution of regional clinical pathways to this variation., Methods: Using data from the Diagnosis Procedure Combination (DPC) database in Japan from April 2011 to March 2013, patients who were diagnosed with "fracture of head and neck of femur" (ICD10 code S72.0) or "pertrochanteric fracture" (S72.1) and received "bipolar hip arthroplasty" or "open reduction and internal fixation" were extracted. A total of 110,133 patients were included. Associations between regional clinical pathways and postoperative LOS were analyzed using cross-sectional analysis with multilevel regression models., Results: Hospitals that implemented a regional clinical pathway showed a significant reduction (13 days) in the postoperative LOS of hip fracture patients. We found a 16% inter-hospital variation in postoperative LOS, which might be explained by hospital-level implementation of regional clinical pathways. Application of regional clinical pathways at the patient level resulted in a 4-day decrease in postoperative LOS., Conclusions: Implementation of regional clinical pathways for hip fracture patients at the hospital level was associated with reduced postoperative LOS, regardless of whether or not pathways were implemented at the patient level. This suggests that regional clinical pathways are effective for patient care management in hospitals., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Total hip arthroplasty is a successful treatment for hip diseases including osteoarthritis, osteonecrosis of the femoral head, and rheumatoid arthritis. Various designs of cemented femoral stems made of stainless steel and titanium alloy have been used. Among them, Charnley-type femoral stems made of stainless steel have often been reported to have good long-term outcome. However, the long-term outcome of the Charnley-type femoral stem made of Ti alloy is yet to be reported. We conducted a retrospective study to assess the long-term outcome of cemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy., Methods: Between October 1988 and February 1997, 341 cemented primary total hip arthroplasties with the Charnley-type femoral stem made of Ti alloy were consecutively performed in our hospital. Among these, 164 patients (211 hips) who underwent this procedure were followed up for more than 12 years, and the surgical hips were analysed clinically and radiologically. The mean follow-up period was 20.6 years. Kaplan-Meier survival analyses were performed to assess femoral component survival. Factors affecting stem revision for aseptic loosening were also investigated using log-rank tests., Results: In the functional assessment, the preoperative Japanese Orthopaedic Association score significantly improved from 47.2 points preoperatively to 79.0 points at the final follow-up. Eventually, 33 femoral stems were revised, of which 12 were revised for aseptic loosening. In the Kaplan-Meier survival analysis, the 20-year survival rates with stem revision for aseptic loosening and radiological stem loosening at the end points were 95.9% and 97.1%, respectively. Original diagnosis (non-osteoarthritis) was the only significant factor for aseptic loosening of the femoral stem., Conclusions: Cemented primary total hip arthroplasty with the Charnley-type femoral stem made of Ti alloy showed excellent outcomes for more than 20 years., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Aims: In the 1990s, a bioactive bone cement (BABC) containing apatite-wollastonite glass-ceramic (AW-GC) powder and bisphenol-a-glycidyl methacrylate resin was developed at our hospital. In 1996, we used BABC to fix the acetabular component in primary total hip arthroplasty (THA) in 20 patients as part of a clinical trial. The purpose of this study was to investigate the long-term results of primary THA using BABC., Patients and Methods: A total of 20 patients (three men and 17 women) with a mean age of 57.4 years (40 to 71), a mean body weight of 52.3 kg (39 to 64), and a mean body mass index (BMI) of 23.0 kg/m 2 (19.8 to 28.6) were evaluated clinically and radiologically. Survival analyses were undertaken, and wear analyses were carried out using a computer-aided method., Results: The mean follow-up was 17.6 years (1.5 to 21.1). Radiological loosening occurred in four sockets with aseptic loosening at a mean of 7.8 years (1.5 to 20.7). Kaplan-Meier survival analyses using revision of the acetabular component, radiological loosening of the acetabular component, and the worst-case scenario with revision of the acetabular component to include the two patients lost to follow-up as endpoints yielded survival rates of 94.7%, 84.4%, and 85.0% at ten years, and 70.0%, 84.4%, and 62.8% at 20 years, respectively. Wear analysis revealed a mean linear wear rate of 0.068 mm per year., Conclusion: The long-term results of primary THAs using BABC were unsatisfactory. Its brittle nature and poor handling properties need to be improved before it becomes an alternative method of fixing the acetabular component in cemented THA. Cite this article: Bone Joint J 2019;101-B:787-792.

We developed a composite cement containing low-content bioactive titania fillers dispersed among specific polymethylmethacrylate (PMMA) polymers and investigated the mechanical properties and bioactivity of this titania bone cement (TBC) under load-bearing conditions in cemented total hip arthroplasty (THA) in adult female beagles. TBC and PMMA bone cement (PBC) were compared using custom-made prostheses. The dogs were killed 1, 3, 6, and 12 months postoperatively. The acetabulum was harvested to evaluate the osteoconductivity of the cement, whereas the femur was harvested for the push-out test and histological analyses. The compressive strength of TBC was significantly higher than that of PBC (p < 0.001), whereas the flexural and tensile strengths, as well as fracture toughness, were equivalent. The bonding strength values for TBC and PBC were 72.9 and 58.0 N/mm at 1 month, 69.4 and 57.2 N/mm at 3 months, 106.1 and 85.0 N/mm at 6 months, and 114.3 and 100.7 N/mm at 12 months, respectively. Histologically, TBC was in direct contact with bone without intervening with fibrous tissue over larger areas and newly formed bone was observed along the cement. The excellent mechanical properties and apparent bioactivity of this novel bone cement indicate its potential utility in clinical practice. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1238-1245, 2019., (© 2018 Wiley Periodicals, Inc.)

Background: Recently, the topical application of tranexamic acid has become widespread, and it is effective in reducing postoperative blood loss and transfusion rate in total hip arthroplasty. There is no consensus on the optimal dose of topical tranexamic acid. This study aimed to assess the efficacy and safety of topical tranexamic acid on postoperative blood loss and determine the optimal topical dose for primary total hip arthroplasty., Methods: This prospective cohort study with a robust protocol enrolled 79 patients who received either 1 or 2 g of topical tranexamic acid in 30 mL normal saline solution or an equivalent volume of normal saline at the end of surgery. The primary outcomes were postoperative drain blood loss and hemoglobin decrease on postoperative day 7. The secondary outcomes were transfusion rate, d-dimer level on postoperative day 7, symptomatic deep vein thrombosis rate, and duration of hospital stay., Results: Both 1 and 2 g tranexamic acid significantly reduced postoperative drain blood loss (p < 0.001). These doses also reduced the hemoglobin concentration decrease on postoperative day 7, but not significantly. Furthermore, 1 and 2 g doses of tranexamic acid had similar effects on postoperative blood loss and hemoglobin concentration decrease. There was no difference in the transfusion rate, d-dimer level, symptomatic deep vein thrombosis rate, and length of hospital stay., Conclusions: The use of topical tranexamic acid at the end of surgery is effective and safe for reducing postoperative blood loss in primary total hip arthroplasty. Topical tranexamic acid at a dose of 1 g may be sufficient and cost-effective, with fewer side effects than the higher dose., (Copyright © 2018 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Dislocation following total hip arthroplasty is mainly caused by malposition. However, the coexistence of neuromuscular disorders is also considered a risk for dislocation due to excessive hip joint laxity. To minimize risk of dislocation, preoperative planning using combined anteversion has been widely used. The recommended combined anteversion angle (the total of cup and stem anteversion angles) is 50 ± 10°., Case Presentation: A 33-year-old Japanese woman underwent elective total hip arthroplasty due to osteonecrosis of the femoral head associated with corticosteroid pulse therapy for myasthenia gravis. Intraoperatively, no tendency of dislocation was found when simulating an evoking position under general anesthesia. In postoperative X-ray and computed tomography scans, cup inclination, cup anteversion, and stem anteversion angles were 37°, 13°, and 35° respectively. The resulting combined anteversion was 48°, which was set as the target along with accurate placement. Her postoperative course was normal and she was discharged without adverse events. Three months postoperatively, due to worsening of myasthenic weakness in her lower extremities while resting, she tended to raise her left limb up using both hands for sitting up. An anterior dislocation occurred when her legs were in a figure-of-four position. She was brought to an emergency department, and reduction of dislocation was performed. It was inferred that myasthenic crisis in the affected limb enabled excessive passive motion due to joint hyperlaxity. At the end of 2016, elective total hip arthroplasty on the contralateral side was performed. Cup anteversion, stem anteversion, and the combined anteversion angles were 27°, 24°, and 51° respectively. We instructed her to exercise care during passive leg movement, which may worsen her myasthenic condition. She returned to a normal life and was able to walk long distances without a cane. No recurrence of dislocation was seen at final follow-up., Conclusions: Even if accurate component orientation is attained in total hip arthroplasty, patients with neuromuscular disorders such as myasthenia gravis have a potential risk of muscle weakness in the affected limb. Therefore, physicians' instructions and patients' careful attention are required to prevent dislocation due to excessive hip joint laxity under conditions of motor weakness.

Background: The Elite-Plus stem has two shape variations: roundback and flanged. The correlation between the radiographic results and stem geometry has not been previously investigated. The objective of this study was to evaluate the long-term primary total hip arthroplasty results using Elite-Plus stems, and the effect of stem geometry on radiographic distal femoral cortical hypertrophy., Methods: We retrospectively evaluated, radiographically, 156 patients (173 hips) who underwent total hip arthroplasty between April 1998 and November 2005, and were followed up for >5 years, postoperatively. Radiographic factors affecting distal femoral cortical hypertrophy were analysed using multivariable logistic regression analysis., Results: The mean follow-up period was 11.6 (5-17.8) years. During follow-up, femoral components were revised in 7 hips; one was revised due to aseptic loosening. Another femoral component was loosened and waiting for revision. The 10- and 15-year survival rates for aseptic stem loosening were 100% and 98.1% (95% CI: 92.5-99.5), respectively. Distal femoral cortical hypertrophy occurred in 23 hips (14.8%), and more often with roundback type (34.1%) than with flanged type (7.2%). Distal femoral cortical hypertrophy was observed in 34.8% of hips with valgus alignment, 11.3% with neutral alignment, and 12.5% with varus alignment. Multivariable logistic regression analysis showed that roundback stem shape and valgus stem alignment significantly affected the occurrence of distal femoral cortical hypertrophy., Conclusions: The Elite-Plus stem has excellent long-term clinical and radiographic results in Japanese patients. The occurrence of distal femoral cortical hypertrophy significantly depends on the shape and alignment of Elite-Plus stems., (Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Few reports are available on the long-term outcomes of femoral component revision by using the cement-in-cement technique. We report the mid- and long-term results of femoral component revision in total hip arthroplasty using the cement-in-cement technique., Methods: Between April 1996 and June 2009, 62 consecutive total hip arthroplasties with femoral component revision were performed in 57 patients by using the cement-in-cement technique. We retrospectively reviewed the cases with a follow-up period of at least five years. Three patients died, and two were lost to follow-up. Thus, 52 patients (57 hips), comprising 51 women and one man, were followed for average 10.8 years., Results: The mean Japanese Orthopaedic Association hip score improved from 57.6 points (range, 28-95 points) preoperatively to 79.8 points (range, 52-98 points) at one year postoperatively and to 77.4 points (range, 59-96 points) at the final follow up. Three revisions of the femoral component were necessary. One of the causes for the revision was a periprosthetic infection that occurred 20 months postoperatively. Another was aseptic loosening that occurred 99 months postoperatively and required revision of the acetabular component. The well-fixed femoral component was revised using the cement-in-cement technique at time of the acetabular revision. The third case was aseptic loosening of the femoral component that occurred 84 months postoperatively. The five-, 10-, and 15-year survival rates for the femoral re-revision due to any reason were 98.4%, 94.0%, and 94.0%, respectively., Conclusion: Use of the cement-in-cement technique for revision total hip arthroplasty resulted in good mid- and long-term radiological and clinical outcomes., (Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to investigate the effects of an exercise program focusing on hip external rotator muscle on physical recovery in the early post-operative period of total hip arthroplasty (THA)., Methods: Patients who underwent THA were randomized to an exercise group (n = 14) or a control group (n = 14). In exercise group, the hip external rotator exercise program was performed 5 times per week for four weeks. Outcome measures were hip pain, hip range of motion, muscle strength of lower extremity and Timed Up and Go (TUG) test., Results: Both the hip abductor strength (effect size = 0.60) and TUG test (effect size= -0.53) in the exercise group improved significantly after the intervention., Conclusions: The results of the present study demonstrated that exercise program focusing on hip external rotator muscle was an effective intervention, especially in improving both hip abductor strength and walking ability in the acute post-THA stage. Implication for Rehabilitation After THA, in order to safely progress patients back to their desired activity level, there is a need to develop rehabilitation strategies to expedite and promote the recovery during the acute postoperative period. Exercise program focusing on hip external rotator muscle may lead to significant improvement of hip abductor muscle strength and gait ability in the acute post-THA stage.

Background: The durability of uncalcined and unsintered hydroxyapatite-poly-l-lactide composite screws is unclear when used for the fixation of acetabular bone graft in total hip arthroplasty under full-weight conditions. We have used this type of screw for the fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty since 2003. Hence, we conducted a follow-up study to assess the safety and efficacy of these screws when used for cemented socket fixation., Methods: In this study, 98 patients (106 cases) who underwent fixation of acetabular bone graft in cemented or reverse-hybrid total hip arthroplasty using hydroxyapatite-poly-l-lactide composite screws were followed up for over 5 years and evaluated clinically and radiographically. The patient population comprised 10 men and 88 women with a mean age of 60.3 years (range, 41-81 years) at the time of surgery. The original diagnosis for primary total hip arthroplasty was secondary osteoarthritis in 97 cases and high hip dislocation in nine cases., Results: The mean follow-up period was 7.6 years (range, 5-11 years). No patient in this series required revision surgery, and no radiographical loosening occurred during the follow-up period. The mean Japanese Orthopaedic Association score improved from 48 (range, 7-73) preoperatively to 87 (range, 50-100) at the final follow-up. Radiographically bone graft consolidation was confirmed in all cases, and no apparent osteolysis around the cemented socket or composite screws was detected. Kaplan-Meier survival analyses with socket revision surgery for any reason, socket loosening, and appearance of a radiolucent line >1 mm in any zone as the endpoints yielded survival rates of 100%, 100%, and 86.8% at 5 years, and 100%, 100%, and 81.0% at 10 years, respectively., Conclusion: This absorbable screw seems to have no negative effects on the mid-term clinical results of cemented socket fixation., (Copyright © 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Fifty-four patients (64 hips) underwent cementless total hip arthroplasty between 2000 and 2003 with a 22-mm zirconia ceramic bearing on highly cross-linked polyethylene, and were evaluated with a mean 11.9-year postoperative follow-up (range, 10-14 years). Linear wear was measured on the anteroposterior radiograph of the hip. No evidence of osteolysis and loosening was found on the final radiograph in any of the cases, and the steady-state linear wear rate was 0.017±0.018 mm/year. No significant correlation was found between the linear wear rate and age, body weight, cup inclination angle, or polyethylene thickness. Highly cross-linked polyethylene showed excellent wear resistance for >10 years when used in combination with 22-mm zirconia heads., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: A lateral approach is common in total hip arthroplasty because of the good exposure it provides and its low complication rates. However, a drawback of the procedure is that the abductor mechanism is damaged when the tendinous insertion of the abductor muscle is split. Here, we describe a wafer technique using ultra-high-molecular-weight polyethylene tape for promising reattachment of the abductor mechanism., Methods: We retrospectively evaluated 120 consecutive primary total hip arthroplasties performed using a modified Mostardi approach, which involved reattaching the trochanter using either a braided polyester suture (polyester suture group, n = 60) or ultra-high-molecular-weight polyethylene tape (UHMWPE tape group, n = 60). The osteotomized fragment was reattached by inducing bone-to-bone contact using 3-mm-wide tapes that were precisely tied with a double-loop sliding knot in conjunction with a cable gun tensioner. The abductor strength and radiographic union rate were postoperatively assessed at 4 weeks and 6 months, respectively., Results: A statistically significant lower incidence of nonunion and cutout was observed in the UHMWPE group (0 and 5.0 %, respectively) compared to the polyester suture group (8.3 and 15 %, respectively). No differences in abductor strength either preoperatively or at 4 weeks postoperatively were observed between the groups. In radiographically healed patients, abductor strength at 4 weeks post-surgery exceeded preoperative strength. The recovery rate of hip abductor strength was 109.9 ± 34.3 % in union patients and 92.9 ± 23.3 % in nonunion patients, which was statistically significant. The mean Japanese Orthopedic Association hip scores improved from 48.6 to 86.8 in union patients and from 50.3 to 85.9 in nonunion patients at 1 year postoperatively; however, this difference was not significant., Conclusions: The modified Mostardi approach using ultra-high molecular weight polyethylene tape can promote successful union of the osteotomized fragment.

Objectives: The aim of this study was to estimate the effect of fondaparinux and enoxaparin combined with mechanical prophylaxis (MP) after total hip arthroplasty (THA) and total knee arthroplasty (TKA). We also investigated the occurrence of pulmonary embolism (PE) and its associated risk factors., Methods: Data were retrospectively collected on patients who underwent THA or TKA between 2008 and 2010 from the Japanese Diagnosis Procedure Combination database (n = 49,678). We extracted information on sex, age, main diagnosis, types of anesthesia, duration of anesthesia, comorbidities, hospital volume, the use of MP, and the use of anticoagulant drugs., Results: The overall occurrence of PE was 0.41%. Multivariate logistic regression analysis showed that the occurrence of PE was significantly higher in females (odds ratio, 2.17; p < 0.001, compared with males), TKA (1.47; p = 0.039, compared with THA), and longer-duration anesthesia (2.63; p = 0.008 in the ≥ 240-min. group compared with the ≤ 119-min. group). Compared with the MP-alone group, the occurrence of PE was significantly reduced in the fondaparinux group (0.58; p = 0.025) and the enoxaparin group (0.59; p = 0.046)., Conclusions: Fondaparinux or enoxaparin combined with MP decreased the occurrence of PE. The risk factors for PE were female patients, TKA, and longer-duration anesthesia (≥ 240 min.).

Introduction: Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in revision hip arthroplasty. Here we examine the clinical and radiographic outcome of this procedure using a cemented stem, including experimental analysis of the initial stability of mesh-grafted bone-cemented stem complexes., Methods: We retrospectively reviewed six hips (six patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 3.9 years (range 2.4-4.8 years). Hip joint function was evaluated using the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of mesh-grafted bone-cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur., Results: The hip score improved from 50 (range 10-84) preoperatively to a mean of 74 (range 67-88) at the final follow-up. The overall implant survival rate was 100 % at five years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within one year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no relationship between IBG reconstruction rates under axial compression and stem subsidence or failure load. In contrast, under rotational load, the rotation angles of the stem to the stainless steel mesh were strongly affected by the IBG reconstruction rate., Conclusions: The short-term results show good outcomes for reconstruction of proximal bone loss with IBG and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half the length of the implanted stem.

Objective: To identify an assessment tool and its cut-off point for indicating ambulatory status 6 months after total hip arthroplasty (THA)., Design: Cross-sectional study., Setting: Kyoto University Hospital., Participants: Eighty-eight patients who underwent unilateral THA., Main Outcome Measure: Lower-extremity muscle strength, hip range of motion and hip pain were measured 6 months after THA. The patients were divided into two groups according to their ability to walk 6 months after THA: an independent ambulation group and a cane-assisted ambulation group., Results: A stepwise multiple logistic regression analysis indicated that age and lower-extremity maximal load were significant variables affecting mid-term ambulatory status following THA. Receiver operating characteristic curve analyses revealed that ambulatory status following THA was indicated more accurately by leg extension strength (cut-off point=8.24N/kg, sensitivity=92%, specificity=82%, area under the curve=0.93) than age., Conclusion: Lower-limb load force with a cut-off point of 8.24N/kg is a reliable assessment tool for indicating ambulatory status 6 months after primary THA., (Copyright © 2013 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.)

Cortical onlay strut allografting is a promising surgical option to reconstruct and reinforce the deficient femur in a hip arthroplasty. However, the union of the allograft to the host bone takes a long time. To accelerate the process of cortical onlay strut allograft healing, we studied the effects of low-intensity pulsed ultrasound (LIPUS) on callus formation. From 2 wk after the operation, LIPUS was given for 20 min/d at each end of the strut allograft. The LIPUS treatment group was assigned 14 allograft transplantations, while 21 control patients were treated without LIPUS. The LIPUS treatment group formed calluses and had complete bridging between the host femur and the allograft faster after operation (16.9 and 29.4 wk after operation, respectively) compared with the control group (40.7 and 82.0 wk after operation, respectively). Our findings showed that LIPUS stimulated bone bonding between the host femur and the cortical onlay strut allografts., (Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Background: Cementless total hip arthroplasty (THA) implants using alkaline and heat treatments were developed to enhance bone bonding. Although bone-bonding ability of the alkali- and heat-treated titanium surface has been demonstrated in animal studies, it remains unknown whether it enhances or provides durable bone bonding in humans., Questions/purposes: We therefore (1) determined long-term survivorship, function, and radiographic signs of failure of fixation of alkali- and heat-treated THA implants; and (2) histologically examined their bone-bonding ability in two human retrievals., Methods: We retrospectively reviewed 58 patients who underwent 70 primary THAs, of whom 67 were available for minimum followup of 8 years (average, 10 years; range, 8-12 years). Survival rate was calculated. Hip function was evaluated using the Japan Orthopaedic Association (JOA) hip scores, and radiographic signs of implant failure were determined from anteroposterior radiographs. Two retrieved implants were investigated histologically., Results: Using revision for any reason as the end point, the overall survival rate was 98% (95% confidence interval, 96%-100%) at 10 years. The patients' average JOA hip scores improved from 47 points preoperatively to 91 points at the time of the last followup. No implant had radiographic signs of loosening. Histologically we observed bone in the pores 2 weeks after implantation in one specimen and apparently direct bonding between bone and the titanium surface in its deep pores 8 years after implantation., Conclusions: Cementless THA implants with alkaline and heat treatments showed a high survival rate. Further study is required to determine whether the treatment enhances direct bone bonding.

Background: Surgical revision after failed total hip replacement is a technically challenging procedure. The aim of this study was to analyze the long-term results of revision total hip replacement using a cemented long femoral component and identify factors that influence the results., Methods: We retrospectively reviewed 34 hips in 33 patients who had undergone revision total hip replacement using a cemented long femoral component between 1994 and 2001. Hip function was evaluated according to the scoring system of the Japanese Orthopaedic Association. Radiographic examination was performed for evaluation of stem loosening, and its possible risk factors were investigated., Results: The mean follow-up duration was 11.3 years (9-15). Perioperative complications included intraoperative femoral cortex perforation (six hips, 18 %), dislocation (five hips, 15 %), deep venous thrombosis (one hip, 3 %) and postoperative periprosthetic fracture (one hip, 3 %). The mean preoperative Japanese Orthopaedic Association hip score was 50.3 ± 14.9 vs 78.2 ± 11.5 at the latest follow-up. The Kaplan-Meier survival rate at 15 years, calculated using radiological failure or re-revision of the femoral component for any reason as the end point, was 87 or 100 %, respectively. The failure-free survival rate for the subgroup with a good-quality cement mantle was significantly higher than that for the subgroup with poor quality (p = 0.033)., Conclusions: The quality of cementation was identified as a significant risk factor for further loosening. Revision total hip replacement using a cemented long femoral component yielded satisfactory long-term results in this series.

Background: Total hip arthroplasty (THA) is an effective procedure that provides patients with long-term relief from pain and enables them to resume their normal daily activities. Preoperative instruction about the functional outcomes and optimum goal of rehabilitation is helpful for patients undergoing THA., Objective: The purposes of this study were: (1) to examine the relationships between preoperative physical functions and ambulation following THA and (2) to identify optimal cutoff values for estimating ambulatory status at 6 months after THA., Design: This was a retrospective study., Methods: The study participants were 204 patients who underwent a unilateral THA. Hip abductor and knee extensor strength were measured and the Timed "Up & Go" Test (TUG) was conducted preoperatively. The patients were divided into 2 groups according to self-reported walking ability at 6 months postoperatively: an independent ambulation group (n=118) and a cane-assisted ambulation group (n=86). Differences between the 2 groups were examined using an unpaired t test or the chi-square test. A stepwise multiple logistic regression analysis was performed with walking ability at 6 months postoperatively as a dependent variable and age, sex, contralateral hip osteoarthritis (ie, whether a participant had contralateral hip osteoarthritis or not), body mass index, hip abductor strength, knee extensor strength, and TUG score as independent variables. Receiver operating characteristic curve analysis was used to identify a cutoff point for classifying the participants into the 2 groups., Results: A stepwise multiple logistic regression analysis selected 3 factors (age, knee extensor strength, and TUG score) as significant variables affecting the midterm ambulatory ability after THA. Moreover, receiver operating characteristic curve analyses revealed that the midterm (ie, 6-month) ambulatory status after THA was more accurately predicted by the patient's TUG score (cutoff point=10 seconds, sensitivity=76.7%, specificity=93.2%, area under the curve=0.93) than by age and knee extensor strength., Limitations: The categorization of ambulatory status in this study was based solely on self-reported walking ability., Conclusion: The findings indicate that patients with a preoperative TUG score of less than 10 seconds are likely to walk without an assistive device at 6 months after THA.

Background: Prosthetic alignment and size are important factors in achieving a long-term survival in TKA. Although two-dimensional and three-dimensional (3-D) planning for component sizing has been introduced, it sometimes is difficult to cut the bones accurately according to preoperative planning. It is unclear whether changing sagittal alignment of the distal femur affects the AP dimension and sizing of the prepared bone., Questions/purposes: We therefore determined whether the AP dimension of the prepared distal femur increases if the distal femur is cut in extension and decreases if it is cut in flexion., Methods: One hundred knees were evaluated using 3-D imaging software. The AP dimension of the cutting surface was measured when the femoral component was aligned perpendicular to the anatomic axis. The measurement was repeated when the distal bone cut was planned in flexed positions of 3° and 5° and extended positions of 3° and 5°., Results: The AP dimension of the prepared femur was increased by 2 and 3 mm with 3° and 5° extension, respectively. The AP dimension of the prepared femur was decreased by 2 and 3 mm with 3° and 5° flexion, respectively., Conclusions: Our data suggest upsizing or downsizing of the femoral component can occur if the femoral osteotomy is performed in at least 3° extension or flexion., Level of Evidence: Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Background and Purpose: Cementless total hip arthroplasty is currently favored by many orthopedic surgeons. The design of the porous surface is critically important for long-term fixation. We examined the clinical and radiographic outcome of the cementless titanium hip implant with a bottom coating of apatite-wollastonite containing bioactive glass ceramic., Methods: We retrospectively reviewed 109 hips (92 patients) that had undergone primary cementless total hip arthroplasty with bioactive glass ceramic bottom-coated implants. The mean follow-up period was 7 (3-9) years. Hip joint function was evaluated with the Merle d'Aubigné and Postel hip score, and radiographic changes were determined from anteroposterior radiographs., Results: The mean hip score improved from 9.7 preoperatively to 17 at the final follow-up. The overall survival rate was 100% at 9 years, when radiographic loosening or revision for any reason was used as the endpoint. 3 stems in 2 patients subsided more than 3 mm vertically within 1 year after implantation. Radiographs of the interface of the stem and femur were all classified as bone ingrowth fixation., Conclusions: The short-term results of this study show good outcome for cementless implants with a bottom coating of apatite-wollastonite containing bioactive glass ceramic.