Chondrogenesis is accompanied by not only cellular renovation, but also metabolic stress. Therefore, macroautophagy/autophagy is postulated to be involved in this process. Previous reports have shown that suppression of autophagy during chondrogenesis causes mild growth retardation. However, the role of autophagy in chondrocyte differentiation still largely remains unclear. Here, we show the important role of autophagy on chondrogenesis. The transition of mesenchymal cells to chondrocytes was severely impaired by ablation of Atg7, a gene essential for autophagy. Mice lacking Atg7 after the transition exhibited phenotypes severer than mutant mice in which Atg7 was removed before the transition. Atg7-deficient chondrocytes accumulated large numbers of glycogen granules, hardly proliferate and died specifically in the proliferative zone without any ER-stress signal. Our results suggest that the suppression of autophagy in prechondrogenic cells drives compensatory mechanism(s) that mitigate defective chondrogenesis, and that autophagy participates in glycogenolysis to supply glucose in avascular growth plates.

Background: Several researchers consider the clinical epicondylar axis (CEA) as the functional flexion-extension axis of the knee. The anterior pelvic plane (APP) is commonly used as an anatomical reference plane of the pelvis. However, no study has investigated the relationship of the APP with the CEA and PCA. In this study, we aimed to investigate the relationship of the APP with the CEA and posterior condylar axis (PCA) in the standing and supine positions. Methods: We recruited 77 healthy Japanese subjects for this study, and carried out measurements using the Hip CAS ® system, a 3D system used for the assessment of lower extremity alignment. Results: The mean femoral neck anteversion was 16.33˚. There was an approximate discrepancy of 6˚ between the male and the female in anatomy (15.73˚ and 21.15˚ in the male and female subjects, respectively). The mean condylar twist angle (CTA) was 6.86˚ and the mean APP-PCA value in the standing position was −6.88˚. The mean APP-CEA value in the standing position was 0.02˚, and the discrepancy between males and females was only 0.21˚ (0.09˚ and −0.13˚ for the male and female subjects, respectively). This meant that Xp axis of APP and CEA were almost parallel. On the other hand, the mean APP-CEA value in the supine position was 7.07˚ (male subjects = 9.48˚; female subjects = 5.62˚). Here, the CEA was approximately parallel to the horizontal axis of the APP, which was compatible with the neutral position of the knee and hip joint, and anatomically and kinesiologically justified in normal subjects. Conclusion: CEA was approximately parallel to the horizontal axis of the APP. These results are compatible with regard to the neutral position of the knee and hip joints, and anatomically and kinesiologically justified in normal subjects. Moreover, CEA is a potential reference axis for the insertion of the femoral component in THA.

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The maximum CSA of the gluteus maximus was found just above the femoral head and that of the gluteus medius was near the lowest end of the sacroiliac joint; hence, CSAs should be calculated at these sites. The CSA reflected muscle volume and strength.

Background: Malpositioning during total hip arthroplasty may cause dislocation, pain, and other complications. To evaluate the potential of sacral slope (SS) as a reliable parameter of pelvic flexion. Methods: We developed a model of pelvic flexion to determine the intraobserver and interobserver variability and reliability of SS measurements by lateral radiography by three independent observers. Results: Measurement error was 1.2° and the intraobserver reliability was moderate to substantial (Interclass correlation coefficient: 0.31 to 0.66). Based on the Spearman-Brown formula, the measurement is reliable if it is done at least seven times by two observers, and four times by three observers. Conclusions: The data suggest that measurement of SS of pelvic flexion is a clinically useful parameter for the optimization of THA conditions.

Global femoral offset (GFO) and femoral offset (FO) reportedly affect outcomes following total hip arthroplasty (THA). However, FO assessed using plain radiography is affected by internal and external rotations of the hip joint. We investigated the relationship between leg length discrepancy and Harris hip score (HHS), and their influence on acetabular offset (AO), FO, GFO, anterior femoral offset, and outcomes after THA. We retrospectively evaluated 140 patients with hip osteoarthritis who underwent THA. A three-dimensional (3D) pelvis and femur model created from computed tomography (data using ZedHip software was used to investigate these parameters. The modified (m)HHS scores were significantly improved from 49.0 to 88.8 in total mHHS, 20.0–44.5 in pain, and 28.9–44.4 points in function. Significant correlations were found between the differences in AO, FO, GFO, and pain score in binominal, with maximum values of − 1.24, + 1.54, and + 0.90 mm/100 cm body height, respectively. The maximum value of GFO and mHHS in binominal was + 1.17 mm/100 cm body height (BH). The optimal range of difference of GFO was − 1.75 to 4.09 mm/100 cm BH. This is the first report using a 3D method for assessing FO. Preoperative planning using the system could improve postoperative function.

Introduction A 2015 study showed a decreasing trend in the incidence of osteoporotic hip fractures in Niigata Prefecture, Japan, which had been increasing. This study aimed to investigate the incidence of osteoporotic hip fractures in 2020, determine the long-term change in the incidence of hip fractures from 1985 to 2020, and assess whether the decline in fracture incidence since 2010 has continued. Materials and Methods We obtained data from the registration forms submitted by hospitals and clinics of patients who lived in Niigata Prefecture and were diagnosed with osteoporotic hip fracture through a survey conducted from January 1, 2020 to December 31, 2020. Results In 2020, 3,369 hip fractures were recorded in Niigata Prefecture. Although the overall incidence of age-specific hip fractures decreased, it increased in patients aged ≥ 90 years, regardless of sex. The proportion of patients receiving anti-osteoporosis drugs prior to hip fracture increased from 7.6% in 2004 to 17.3% in 2020. Notably, surgical treatment should be performed as early as possible, and the preoperative waiting time was 2.9 days, which was mainly due to holidays. Conclusion The incidence of hip fractures in Niigata Prefecture has gradually increased over the past 35 years, with an increasing change observed in the very elderly recently in 2020. Although the treatment of osteoporotic hip fractures in Niigata Prefecture is adequate, improvements may include increasing the rate of adoption of osteoporosis treatment further and decreasing the number of days of preoperative waiting.

Background and Objectives: In the field of orthopedic surgery, novel techniques of three-dimensional shape modeling using two-dimensional tomographic images are used for bone-shape measurements, preoperative planning in joint-replacement surgery, and postoperative evaluation. ZedView® (three-dimensional measurement instrument and preoperative-planning software) had previously been developed. Our group is also using ZedView® for preoperative planning and postoperative evaluation for more accurate implant placement and osteotomy. This study aimed to evaluate the measurement error in this software in comparison to a three-dimensional measuring instrument (3DMI) using human bones. Materials and Methods: The study was conducted using three bones from cadavers: the pelvic bone, femur, and tibia. Three markers were attached to each bone. Study 1: The bones with markers were fixed on the 3DMI. For each bone, the coordinates of the center point of the markers were measured, and the distances and angles between these three points were calculated and defined as “true values.” Study 2: The posterior surface of the femur was placed face down on the 3DMI, and the distances from the table to the center of each marker were measured and defined as “true values.” In each study, the same bone was imaged using computed tomography, measured with this software, and the measurement error from the corresponding “true values” was calculated. Results: Study 1: The mean diameter of the same marker using the 3DMI was 23.951 ± 0.055 mm. Comparisons between measurements using the 3DMI and this software revealed that the mean error in length was <0.3 mm, and the error in angle was <0.25°. Study 2: In the bones adjusted to the retrocondylar plane with the 3DMI and this software, the average error in the distance from the planes to each marker was 0.43 (0.32–0.58) mm. Conclusion: This surgical planning software could measure the distance and angle between the centers of the markers with high accuracy; therefore, this is very useful for pre- and postoperative evaluation.