RESUMEN
OBJECTIVES: This study documents the time elapsed from the diagnosis of osteonecrosis of the femoral head (ONFH) to surgery, exploring the factors that influence ONFH severity. DESIGN: Retrospective observational study of a nationwide database. SETTING: The Kaplan-Meier method with log-rank tests was applied to examine the period from definitive diagnosis of ONFH to surgery using any surgery as the end point. For bilateral cases, the date of the first surgery was the endpoint. PARTICIPANTS: This study included 2074 ONFH cases registered in 34 university hospitals and highly specialised hospitals of the multicentre sentinel monitoring system of the Japanese Investigation Committee between 1997 and 2018. MAIN OUTCOME MEASURE: The primary outcome was the time from diagnosis to surgery. The secondary outcome was the proportion of subjects remaining without surgery at 3, 6 and 9 months, and at 1, 2 and 5 years after diagnosis. RESULTS: The median time to surgery was 9 months (IQR 4-22 months) after diagnosis of ONFH. The time to surgery was significantly shorter in the alcohol alone group and the combined corticosteroid and alcohol group than in the corticosteroid alone group (p=0.018 and p<0.001, respectively), in early stage ONFH with no or mild joint destruction (stages II and III, p<0.001), and with joint preserving surgery (p<0.001). The proportion without surgery was 75.8% at 3 months, 59.6% at 6 months, 48.2% at 9 months, 40.5% at 1 year, 22.2% at 2 years and 8.3% at 5 years. CONCLUSION: ONFH has been considered to be an intractable disease that often requires surgical treatment, but the fact that surgery was performed in more than half of the patients within 9 months from diagnosis suggests severe disease with a significant clinical impact. TRIAL REGISTRATION NUMBER: Chiba University ID1049.
Asunto(s)
Necrosis de la Cabeza Femoral , Humanos , Japón/epidemiología , Necrosis de la Cabeza Femoral/diagnóstico , Necrosis de la Cabeza Femoral/cirugía , Cabeza Femoral/cirugía , Estudios Retrospectivos , CorticoesteroidesAsunto(s)
Artroplastia de Reemplazo de Cadera , Fémur , Osteotomía , Humanos , Osteotomía/métodos , Fémur/cirugía , Fémur/diagnóstico por imagen , Artroplastia de Reemplazo de Cadera/métodos , Artroplastia de Reemplazo de Cadera/instrumentación , Resultado del Tratamiento , Femenino , Masculino , Persona de Mediana Edad , Recuperación de la Función , Factores de Tiempo , Articulación de la Cadera/cirugía , Articulación de la Cadera/fisiopatología , Articulación de la Cadera/diagnóstico por imagen , Fenómenos Biomecánicos , Adulto , Rango del Movimiento Articular , Estudios RetrospectivosRESUMEN
Snapping knee syndrome on the medial side is rare. Here, we report the case of a patient with snapping knee syndrome of the sartorius with knee osteoarthritis. A large osteophyte at the posteromedial femoral condyle impinged on the sartorius myotendinous junction, causing painless snapping. The patient was successfully treated with osteophyte removal and total knee arthroplasty while preserving the tendon. Hence, tendon release or resection to treat snapping syndrome is not always necessary if the underlying cause can be eliminated. Furthermore, we found that while tendon tension is important for the occurrence of snapping syndrome, the impingement site determines the occurrence of snapping pain.
RESUMEN
OBJECTIVE: The aim of this study was to elucidate the efficacy of T2-mapping MRI and correlation with histology for the evaluation of tissue repair quality following the first-in-human implantation of an autologous tissue engineered construct. DESIGN: We directly compared the results of T2-mapping MRI of cartilage repair tissue with the histology of a biopsy specimen from the corresponding area at 48 weeks postoperatively in 5 patients who underwent the implantation of a scaffold-free tissue-engineered construct generated from autologous synovial mesenchymal stem cells to repair an isolated cartilage lesion. T2 values and histological scores were compared at each of 2 layers of equally divided halves of the repair tissue (upper and lower zones). RESULTS: Histology showed that the repair tissue in the upper zone was dominated by fibrous tissue and the ratio of hyaline-like matrix increased with the depth of the repair tissue. There were significant differences between upper and lower zones in histological scores. Conversely, there were no detectable statistically significant differences in T2 value detected among zones of the repair tissue, but zonal differences were detected in corresponding healthy cartilage. Accordingly, there were no correlations detected between histological scores and T2 values for each repair cartilage zone. CONCLUSION: Discrepancies in the findings between T2 mapping and histology suggest that T2 mapping was limited in ability to detect details in the architecture and composition of the repair cartilage.
Asunto(s)
Cartílago Articular , Células Madre Mesenquimatosas , Cartílago Articular/diagnóstico por imagen , Cartílago Articular/patología , Cartílago Articular/cirugía , Condrocitos , Humanos , Imagen por Resonancia Magnética/métodos , Trasplante AutólogoRESUMEN
PURPOSE: The Clinical Practice Guidelines for Osteonecrosis of the Femoral Head (ONFH) 2019 Edition, written by the working group for ONFH guidelines of the Japanese Investigation Committee (JIC) for ONFH under the auspices of the Japanese Ministry of Health, Labour, and Welfare and endorsed by the Japanese Orthopaedic Association, were published in Japanese in October 2019. The objective of this guideline is to provide a support tool for decision-making between doctors and patients. METHODS: Procedures for developing this guideline were based on the Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014, which proposed an appropriate method for preparing clinical guidelines in Japan. RESULTS: This clinical practice guideline consists of 7 chapters: epidemiology; pathology; diagnosis; conservative therapy; surgical treatment: bone transplantation/cell therapy; surgical treatment: osteotomy; and surgical treatment: hip replacement. Twelve background questions and 13 clinical questions were determined to define the basic features of the disease and to be addressed when deciding treatment in daily practice, respectively. CONCLUSIONS: The clinical practice guidelines for the ONFH 2019 edition will be useful for physicians, investigators, and medical staff in clinical practice, as well as for patients, during the decision-making process when defining how to treat ONFH.
Asunto(s)
Artroplastia de Reemplazo de Cadera , Necrosis de la Cabeza Femoral , Ortopedia , Cabeza Femoral , Necrosis de la Cabeza Femoral/diagnóstico , Necrosis de la Cabeza Femoral/terapia , Humanos , Japón/epidemiologíaRESUMEN
During pharmaceutical manufacturing, line-scan hyperspectral imaging enables us to collect several electromagnetic spectra at each pixel in a two-dimensional plane for each tablet. The present study quantitatively determines two independent values of the active pharmaceutical ingredient (API) content in a tablet and the amount of coating on a surface of the same tablet simultaneously; the process is visualized by means of a near-infrared hyperspectral imaging (NIR-HSI) system combined with multivariate data analysis at a typical manufacturing speed of 4,000 tablets per minute. The API content and the amount of coating were controlled to be in the range 80-120% and 0-7 mg, respectively. The results of the cross validation of regression models demonstrated a coefficient of determination (R2) of 0.942, a root-mean-square error of cross validation (RMSECV) of 3.48% for the API content, an R2 of 0.939, and an RMSECV of 0.46 mg for the amount of coating. These results demonstrated that the API content in a tablet as well as the amount of coating on the surface of the same tablet can be simultaneously determined with sufficient accuracy. This technique is practically applicable to process analytical technology in pharmaceutical manufacturing.
Asunto(s)
Imágenes Hiperespectrales , Espectroscopía Infrarroja Corta , Análisis de los Mínimos Cuadrados , Análisis Multivariante , Comprimidos , Tecnología FarmacéuticaRESUMEN
STUDY DESIGN: This was a retrospective case series at a single institution. OBJECTIVE: The study was performed to investigate the characteristics of spinal injuries in survivors of suicidal jumping. SUMMARY OF BACKGROUND DATA: Spinal fracture/dislocation is associated with high-energy trauma such as that induced by motor vehicle accidents. Survivors of suicidal jumping sometimes sustain spinal injuries. However, the characteristics of such spinal injuries are unclear. METHODS: We identified 87 survivors of suicidal jumping who sustained spinal injuries from 2007 to 2016 in our institution. We compared the demographic data, radiological findings, neurological status, associated injuries, treatments, and mental health conditions between these 87 survivors and 204 non-suicidal patients with spinal injury. RESULTS: Suicidal jumpers were predominantly female (67%) and 10 years younger than non-suicidal patients. Mental health problems, mainly schizophrenia and depression, were diagnosed in 77% of suicidal jumpers. Neurological damage from spinal trauma was generally less severe in suicidal jumpers than in non-suicidal patients. Most spinal injuries in suicidal jumpers were located in the thoracic or lumbar spine region (85%). Among comorbid injuries, extremity injuries were highly associated with spine injury in suicidal jumpers. Nearly 70% of suicidal jumpers exhibited extremity injury in contrast to 33% of non-suicidal patients. Approximately, 25% of suicidal jumpers underwent surgical treatment. Surgical treatment was similarly performed on suicidal jumpers and non-suicidal patients regardless of the discrepancy in neurological damage between these two groups. CONCLUSION: Spinal injuries in suicidal jumpers differed from spinal injuries in non-suicidal patients with regard to sex, age, mental health condition, injury location, neurologic damage, and associated injuries. Most survivors of suicidal jumping were young female patients with mental health problems. They tended to have thoracic and lumbar spine trauma rather than cervical trauma with less severe neurological deficits and a higher incidence of accompanying limb injury. LEVEL OF EVIDENCE: 3.
Asunto(s)
Traumatismos Vertebrales/diagnóstico por imagen , Traumatismos Vertebrales/etiología , Intento de Suicidio , Suicidio , Adulto , Femenino , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Fracturas de la Columna Vertebral/diagnóstico por imagen , Fracturas de la Columna Vertebral/etiología , Fracturas de la Columna Vertebral/psicología , Fracturas de la Columna Vertebral/cirugía , Traumatismos Vertebrales/psicología , Suicidio/psicología , Intento de Suicidio/psicología , Sobrevivientes/psicología , Vértebras Torácicas/diagnóstico por imagen , Vértebras Torácicas/cirugía , Adulto JovenRESUMEN
BACKGROUND: Articular cartilage has limited healing capacity, owing in part to poor vascularity and innervation. Once injured, it cannot be repaired, typically leading to high risk for developing osteoarthritis. Thus, cell-based and/or tissue-engineered approaches have been investigated; however, no approach has yet achieved safety and regenerative repair capacity via a simple implantation procedure. PURPOSE: To assess the safety and efficacy of using a scaffold-free tissue-engineered construct (TEC) derived from autologous synovial membrane mesenchymal stem cells (MSCs) for effective cartilage repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Five patients with symptomatic knee chondral lesions (1.5-3.0 cm2) on the medial femoral condyle, lateral femoral condyle, or femoral groove were included. Synovial MSCs were isolated from arthroscopic biopsy specimens and cultured to develop a TEC that matched the lesion size. The TECs were then implanted into chondral defects without fixation and assessed up to 24 months postoperatively. The primary outcome was the safety of the procedure. Secondary outcomes were self-assessed clinical scores, arthroscopy, tissue biopsy, and magnetic resonance image-based estimation of morphologic and compositional quality of the repair tissue. RESULTS: No adverse events were recorded, and self-assessed clinical scores for pain, symptoms, activities of daily living, sports activity, and quality of life were significantly improved at 24 months after surgery. Secure defect filling was confirmed by second-look arthroscopy and magnetic resonance imaging in all cases. Histology of biopsy specimens indicated repair tissue approaching the composition and structure of hyaline cartilage. CONCLUSION: Autologous scaffold-free TEC derived from synovial MSCs may be used for regenerative cartilage repair via a sutureless and simple implantation procedure. Registration: 000008266 (UMIN Clinical Trials Registry number).
Asunto(s)
Autoinjertos/cirugía , Articulación de la Rodilla/cirugía , Membrana Sinovial/trasplante , Ingeniería de Tejidos , Adulto , Femenino , Humanos , Masculino , Trasplante de Células Madre Mesenquimatosas , Persona de Mediana Edad , Proyectos Piloto , Andamios del TejidoRESUMEN
BACKGROUND: Prevalence of developmental hip dysplasia is high in Japan. Exercise therapy has been proven effective to treat certain aspects of hip osteoarthritis. Moreover, therapy provided via digital video discs (DVDs) and websites allows patients to exercise in the comfort of their own homes. However, no studies have evaluated the effectiveness of visual instructions in patients with hip disorders. OBJECTIVE: This study aimed to compare the effectiveness of exercise therapy administered via DVD and that administered via a website. METHODS: We developed a six-step progressive exercise therapy program for patients with hip osteoarthritis, which included three kinds each of open kinetic chain and closed kinetic chain exercises. Once the program was developed, exercise DVDs were produced. In addition to the six-step exercise program, our website was enabled to count the number of exercises performed by each patient and was accessible via the Internet at any time. Patients with hip osteoarthritis for whom surgery was not advised were enrolled by one university hospital in the Kansai area in Japan. Clinical symptoms and hip function were quantified using the Japanese Orthopedic Association Hip Disease Evaluation Questionnaire (JHEQ) and the Oxford Hip Score (OHS). Quality of life was measured using the SF-8 Health Survey, and self-efficacy for continued exercise was measured using the General Self-Efficacy Scale (GSES). Questionnaires were completed preintervention and after 6 months. RESULTS: At 6-month follow-up, 10 DVD users (1 male, 9 female; mean age 51.3, SD 16.1 years) and 18 website users (2 male, 16 female; mean age 52.4, SD 10.4 years) were reachable. The change in each parameter could not be confirmed a significant improvement. However, most items tended to reflect overall improvement during the 6 months of intervention (P=.05-.94; paired t test). Regarding effect size, we considered a small effect to be greater than 0.2. Little effect was observed for JHEQ pain, SF-8 physical component summary (PCS), and SF-8 mental component summary in the DVD group, as well as OHS, SF-8 (PCS), and GSES in the website group. CONCLUSIONS: When comparing the effectiveness of exercise therapy between our DVD and website, we found that although both groups tended to improve in physical function, only the website group showed tendency of enhanced self-efficacy.
RESUMEN
In this study, the distribution of biomaterials and its molecular mechanism of embryonic development in Japanese medaka fish were analyzed nondestructively and noninvasively without staining using near-infrared (NIR) imaging. The microscopic NIR imaging system used in this research was a device capable of ultra-high-speed imaging; using this system, one can acquire microscopic imaging data in a few seconds. Therefore, the medaka eggs remained alive throughout measurements and were successfully monitored in vivo. The distributions of biomolecules were examined by mapping the intensities of NIR bands resulting from lipids, proteins and water in 2 dimensions (2D). The structures of eyes, lipid bilayer membranes, micelles and water-structure differences at the interface of different substances constituting different structures on the egg were visualized. Furthermore, insights on the metabolic mechanisms of lipids and membrane functions were drawn from the biased distribution of lipoproteins and the presence of unsaturated fatty acids in the egg membrane. These results indicated the potential for NIR imaging in evaluating the biological functions and metabolic systems of cells and embryos.
Asunto(s)
Embrión no Mamífero/diagnóstico por imagen , Fertilización , Rayos Infrarrojos , Microscopía , Oryzias/embriología , Óvulo/fisiología , Animales , Factores de TiempoRESUMEN
The purpose of this study was to clarify bone turnover marker levels in rapidly destructive coxopathy (RDC). Twenty patients with RDC (mean age, 72 ± 11 years; 3 men, 17 postmenopausal women), 111 with osteoarthritis (OA) (age, 60 ± 10 years; 15 men, 13 premenopausal women, 83 postmenopausal women), and 18 with osteonecrosis of femoral head (ON) (55 ± 14 years; 11 men, 3 premenopausal women, 4 postmenopausal women), and 100 patients with femoral neck fracture (FNF) (81 ± 10 years; 27 men, 73 postmenopausal women) were included. Serum tartrate-resistant acid phosphatase 5b (TRACP-5b), bone alkaline phosphatase (BAP), matrix metalloproteinase-3 (MMP-3) levels, and bone mineral density (BMD) of proximal femur and lumbar spine were investigated. TRACP-5b levels were significantly higher in RDC than in OA and ON, whereas BAP levels were higher in RDC than in OA (P < 0.05). MMP-3 levels were higher in RDC and ON than in OA (P < 0.05). TRACP-5b were higher in RDC than OA (P < 0.05) and FNF (P < 0.05) in performing propensity score matching; there were no differences in BMD between RDC and OA. TRACP-5b showed the largest area under the curve (AUC, 0.82) according to receiver operating characteristic (ROC) curve analysis for diagnosing RDC against OA and ON. AUCs of BAP and MMP-3 were 0.78 and 0.74. The respective sensitivities and specificities were 70.0 % and 85.3 % for TRACP-5b (cutoff, 623 mU/dl), 95.0 % and 57.1 % for BAP (13.8 U/l), and 70.0 % and 76.4 % for MMP-3 (52.7 ng/ml). The lack of differences in BMD suggested that high bone turnover marker levels may reflect osteoclast cell activation in RDC hips. Serum TRACP-5b and BAP could be RDC markers.
Asunto(s)
Biomarcadores/sangre , Enfermedades Óseas/sangre , Remodelación Ósea , Adulto , Anciano , Fosfatasa Alcalina/sangre , Densidad Ósea , Enfermedades Óseas/enzimología , Estudios de Cohortes , Femenino , Fracturas del Cuello Femoral/sangre , Fracturas del Cuello Femoral/enzimología , Humanos , Masculino , Metaloproteinasa 3 de la Matriz/sangre , Persona de Mediana Edad , Osteoartritis/sangre , Osteoartritis/enzimología , Puntaje de Propensión , Curva ROC , Fosfatasa Ácida Tartratorresistente/sangreRESUMEN
PURPOSE: Rotational acetabular osteotomy (RAO) is used to treat developmental hip dysplasia (DDH). It requires detailed anatomical knowledge of the pelvic anatomy and three-dimensional cognitive skills. We addressed whether a computer navigation system combined with a preoperative computed tomography-based plan enabled surgeons to perform RAO safely and reliably through a mini-incision regardless of their level of experience with performing osteotomies. METHODS: We enrolled 24 patients (25 hips) with DDH (radiographic grade 0 or 1 osteoarthritic changes: Tönnis classification). Using the navigation system, four surgeons performed RAO via a mini-incision transtrochanteric approach. Two experienced surgeons treated 15 patients (16 hips). Two surgeons with low-level RAO experience treated nine patients (9 hips). Operative data and clinical and radiographic outcomes were compared. Average follow-up was 3.2 years. RESULTS: There were no significant differences in the (1) incision length, operation time, or intraoperative blood loss; (2) numerical pain rating scale score and Western Ontario and McMaster Universities Osteoarthritis Index Scale score at 1, 2 years, and at the latest follow-up; (3) preoperative and postoperative acetabular coverage of the femoral head, postoperative joint congruency, postoperative medial and distal femoral head displacement, or acetabular thickness; and (4) positional accuracy of iliac, pubic, and ischial osteotomy and accuracy of acetabular coverage of the femoral head. CONCLUSIONS: Clinical and radiographic outcomes of RAO with navigation were not influenced by the surgeons' level of osteotomy experience.
Asunto(s)
Acetábulo/cirugía , Competencia Clínica , Osteotomía/métodos , Adolescente , Adulto , Femenino , Cabeza Femoral/diagnóstico por imagen , Estudios de Seguimiento , Luxación Congénita de la Cadera , Humanos , Imagenología Tridimensional , Masculino , Persona de Mediana Edad , Pelvis/diagnóstico por imagen , Periodo Preoperatorio , Reproducibilidad de los Resultados , Estudios Retrospectivos , Cirujanos , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento , Adulto JovenRESUMEN
BACKGROUND: Inadequate soft-tissue tension in total hip arthroplasty is regarded as one cause of dislocation or abductor muscle weakness. The purpose of the present study was to assess how the postoperative discrepancy in limb offset (consisting of both femoral offset and acetabular offset) affects soft-tissue tension compared with other factors among patients with unilateral hip disease undergoing total hip arthroplasty. METHODS: A total of 89 consecutive patients underwent mini-incision total hip arthroplasty involving an anterolateral or posterior approach and with use of a computer navigation system. Soft-tissue tension was measured by applying traction amounting to 40% of body weight with the joint positioned at 0°, 15°, 30°, and 45° of flexion. The separation between the cup and the prosthetic head was measured using the navigation system. RESULTS: The cup-head separation differed significantly for varying angles of flexion (p < 0.001), with the greatest distance noted at 15° of flexion (mean and standard deviation, 11 ± 5 mm). Stepwise multiple regression analysis showed that postoperative limb-offset discrepancy, an anterolateral approach, and preoperative abduction range of motion were correlated with the cup-head separation at 15° of flexion. Postoperative limb-offset discrepancy was negatively correlated with the cup-head separation at 0°, 15°, and 30° of flexion. CONCLUSIONS: Postoperative limb-offset discrepancy significantly affected the soft-tissue tension in total hip arthroplasty at varying degrees of flexion. This indicated that it is important to restore normal limb offset without overlengthening to obtain adequate soft-tissue tension in total hip arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Asunto(s)
Artritis Reumatoide/cirugía , Artroplastia de Reemplazo de Cadera/métodos , Luxación de la Cadera/cirugía , Articulación de la Cadera/cirugía , Osteoartritis de la Cadera/cirugía , Osteonecrosis/cirugía , Rango del Movimiento Articular/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Prótesis de Cadera , Humanos , Masculino , Persona de Mediana Edad , Periodo Posoperatorio , Resultado del TratamientoRESUMEN
The optimal reorientation of the acetabulum for developmental dysplasia of the hip (DDH) is unknown in terms of hip range-of-motion (ROM). The simulated ROMs of 52 DDHs after rotational acetabular osteotomy (RAO) with several patterns of femoral head coverage and those of 73 normal hips were analyzed using computer models reconstructed from CT images. After RAO with a lateral center edge angle (LCEA) of 30° and an anterior center edge angle (ACEA) of 55° producing coverage similar to that of normal hips, the maximal flexion and maximal internal rotation at 110° flexion with 20° adduction were significantly smaller than those of the normal group. To achieve ROMs after RAO similar to those of the normal group, an LCEA of 30° with an ACEA of 45°, an LCEA of 25° with an ACEA of 45° to 50°, and an LCEA of 20° with an ACEA of 50° could be preferred angles to target, even though they provided smaller coverage than that of normal hips. After RAO producing femoral head coverage similar to that of normal hips, the maximal flexion and the maximal internal rotation at 110° flexion with 20° adduction were significantly smaller than those of the normal group.
Asunto(s)
Luxación de la Cadera/cirugía , Articulación de la Cadera/fisiología , Rango del Movimiento Articular , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Persona de Mediana Edad , Osteotomía , Estudios Retrospectivos , Adulto JovenRESUMEN
Rotation of the femur is usually measured by the posterior condylar line (PCL). However, the functional position of the PCL has not been studied well. The angles between the PCL and the horizontal body line (HBL) were measured on preoperative computed tomographic (CT) images of 324 hips with osteoarthritis and compared with the CT images taken after hip arthroplasty. The PCL rotated 0.4° (±10.9° SD) internally from the HBL on preoperative CT images and was significantly correlated with femoral anteversion, Kellgren-Lawrence grade, and sex. On postoperative CT images, the PCL rotated 10.1° (interquartile range, 1.7°-15.5°) internally from the HBL. There was individual variance in the position of the PCL, and caution may be needed when using it as a rotational reference.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Fémur/cirugía , Osteoartritis de la Cadera/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Fémur/anatomía & histología , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Osteoartritis/cirugía , Periodo Posoperatorio , Periodo Preoperatorio , Valores de Referencia , Reproducibilidad de los Resultados , Rotación , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Muscle atrophy in osteoarthritis (OA) patients is expected to recover after total hip arthroplasty (THA) because of the increase in activity levels. Although some reports have shown an increase in the thigh muscles (Th) after THA, no reports of increases in the gluteal muscles and of analyses of the factors related to muscle recovery have been published. In this study, the changes in the gluteal and Th volumes after THA were quantitatively evaluated using computed tomography (CT) images, and the factors related to muscle recovery were analyzed. METHODS: The subjects were 40 OA hips with CT images taken 3 weeks after THA (first postoperative [postop] CT) and more than 2 years after THA (second postop CT). The cross-sectional areas of gluteus maximus (G-max), gluteus medius (G-med), and Th were measured in both CT images. The factors related to muscle recovery that were measured and evaluated were age, gender, days from operation, surgical approach, Kellgren-Lawrence grades, and hip functional score (Japanese Orthopaedics Association hip score). RESULTS: All measured cross-sectional areas of the operated side increased significantly from the first postop CT to the second postop CT (G-max, 40%; G-med, 11%; and Th, 20%). In the analysis of the factors related to muscle recovery, the increase rate of G-max correlated significantly with patient age, and the increase rate of G-med correlated significantly with the increase in Japanese Orthopaedics Association hip score. CONCLUSIONS: Hip OA can lead to atrophy of the gluteal and Th, but the muscle volume can recover more than 2 years after THA.