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en: Relationship between iliopsoas muscle surface pressure and implant alignment after total hip arthroplasty: a cadaveric study.

en: Iliopsoas impingement after total hip arthroplasty is caused by the implant irritating the iliopsoas muscle, but changes in the iliopsoas muscle have not been quantitatively evaluated. This study assessed changes in the surface pressure of the iliopsoas muscle when the implant alignment was varied. Total hip arthroplasty was performed in 10 fresh-frozen cadaveric hips. We evaluated the maximum and mean surface pressure of the iliopsoas muscle with the hip in 20° and 10° extension, the neutral position, and 10° flexion when the anterior cup protrusion length (ACPL), stem version, and stem offset were varied. When the ACPL was changed to 0, 3, and 6 mm in 20° extension, the maximum surface pressure was significantly increased for ACPL of 6 mm compared with 0 mm. Decreased stem anteversion resulted in a significant reduction in both the maximum and mean surface pressure compared with native anteversion from 20° extension to the neutral position. Increased stem offset resulted in significant increases in the maximum and mean surface pressure of the iliopsoas muscle compared with decreased stem offset in 20° extension. Not only large ACPL but also changes in stem version and offset affected the maximum surface pressure of the iliopsoas muscle.

en: Scientific Reports

ja: Scientific Reports


en: Between-day reliability and minimum detectable change of the Conventional Gait Model 2 and Plug-in Gait Model during running.

en: The between-day reliability of CGM2 was mostly good to excellent for lower limb kinematics and kinetics during running. We believe that CGM2 can more accurately assess kinematic differences between the coronal and transverse planes than the PiG.

en: Gait & Posture

ja: Gait & Posture


en: Contributions of the ischiofemoral ligament, iliofemoral ligament, and conjoined tendon to hip stability after total hip arthroplasty : a cadaveric study

en: An adequate soft tissue balance is important in total hip arthroplasty (THA). This study assessed the contribution of the iliofemoral ligament, ischiofemoral ligament, and conjoined tendon to the range of hip rotation after THA and hip stability in response to axial traction. THA was performed in eight fresh-frozen cadaveric specimens via an anterolateral approach using a navigation system. The ischiofemoral ligament, the medial arm of the iliofemoral ligament, and the conjoined tendon were resected in that order. The ranges of external and internal rotation and the amount of movement of the femoral head in response to axial traction were measured with the hip in 10° of extension, the neutral position, and in 10°, 30°, and 60° of flexion. Resection of the medial arm of the iliofemoral ligament significantly increased the range of external rotation in 10° of extension, the neutral position, and in 10°, 30°, and 60° of flexion. The conjoined tendon was the most important inhibitor of internal rotation from 10° of extension to 30° of flexion. Although each single element had a minor role in stabilizing the hip when axial traction was applied, resection of two or more elements significantly affected joint stability. The iliofemoral ligament and conjoined tendon are the main inhibitors of external rotation and internal rotation, respectively, when THA is performed using an anterior or anterolateral approach. Resection of two or more elements could greatly affect hip stability when axial traction is applied.

en: Journal of Orthopaedic Research

ja: Journal of Orthopaedic Research


en: One-year follow-up ultrasonographic study of the subchondral bone surface of the distal femoral epiphysis in children aged 9-11 years.

en: Subchondral bone surface irregularity of the distal femoral epiphysis was more common on US in growing children aged 9-11 years, and transition from an irregular to a smooth outline accelerated after age 10 years. US is a reliable method for assessing the morphology of the distal femoral epiphysis and could be a useful screening tool for detecting OCD.

en: Journal of Pediatric Orthopaedics. Part B


en: Limiting the Pitch Count in Youth Baseball Pitchers Decreases Elbow Pain.

en: A pitch count limit of 70 pitches per day for baseball pitchers 12 years could be more protective against elbow pain and reduced flexion than a limit of 7 innings per day, but it may not be effective for reducing the risk of capitellar OCD.

en: Orthopaedic Journal of Sports Medicine

ja: Orthopaedic Journal of Sports Medicine


en: Quadriceps strength to body weight ratio is a significant indicator for initiating jogging after anterior cruciate ligament reconstruction.

en: Quadriceps strength recovery after anterior cruciate ligament (ACL) reconstruction is an important criterion for progress in rehabilitation and return to sports. The purpose of this study was to determine whether quadriceps strength to body weight ratio (QS/BW) is a significant indicator for initiating jogging after ACL reconstruction.

ja: QS/BW is a significant indicator for safely initiating jogging 3 months after ACL reconstruction. The cut-off value of QS/BW for initiating jogging was 1.45 Nm/kg.

en: The Knee

ja: The Knee


en: Osteochondritis Dissecans of the Capitellum :Review of the Literature.

en: Osteochondritis dissecans (OCD) of the capitellum is a leading cause of elbow disability in adolescent baseball players. Previous studies have not found an association of player position with capitellar OCD. Elbow pain and a longer playing history might be related to progression of capitellar OCD but do not in themselves increase the risk of development of the condition. The cause of capitellar OCD is likely to include a combination of repetitive microtrauma and internal factors, such as ischemia and genetic predisposition. A combination of radiography, computed tomography, magnetic resonance imaging, and ultrasonography have aided our understanding of the pathology of capitellar OCD. Screening using ultrasonography enables early detection and provides an opportunity for successful conservative treatment. Treatment has conventionally included both operative and nonoperative measures based on the stage and size of the lesion, skeletal maturity, subjective symptoms, and structural integrity of the cartilage. Early-stage lesions respond better to nonoperative treatment than those in more advanced stages. Operative indications include persistent symptoms despite nonoperative treatment, symptomatic loose bodies, and displacement or detachment of fragments. J. Med. Invest. 67 : 217-221, August, 2020.

en: The Journal of Medical Investigation : JMI


en: Factors correlating with recovery of quadriceps strength after double-bundle anterior cruciate ligament reconstruction with hamstring tendon autografts.

en: Recovery of quadriceps strength after anterior cruciate ligament (ACL) reconstruction is one of the criteria used to promote rehabilitation and return to play. The purpose of this study was to investigate the factors associated with recovery of quadriceps strength after ACL reconstruction with hamstring tendon autografts.

ja: Postoperative quadriceps strength index at 6 months after double-bundle ACL reconstruction with hamstring tendon autografts was affected by preoperative quadriceps strength index. Adequate preoperative quadriceps strength may need to be considered in order to facilitate better recovery of quadriceps strength after ACL reconstruction and to support an earlier return to sports activities.

en: European Journal of Orthopaedic Surgery & Traumatology


en: Factors Associated With Knee Pain and Heel Pain in Youth Soccer Players Aged 8 to 12 Years.

en: In this study of youth soccer players, knee pain was associated with older age and more years of play, but heel pain was not significantly associated with any factor.