Trendelenburg gait after total hip arthroplasty due to reduced muscle contraction of the hip abductors and extensors.

Background: Despite experiencing pain relief and improved activities of daily living after total hip arthroplasty (THA) for osteoarthritis of the hip, a Trendelenburg gait may be observed in some patients. The concentric and eccentric contraction patterns of hip muscles in a Trendelenburg gait are not well understood. Methods: This study included 89 patients (28 males and 61 females, mean age 66.5 ± 8.4 years, mean postoperative period 1.3 ± 0.4 years) after unilateral THA without functional impairment on the contralateral side. Gait analysis utilized a three-dimensional motion capture system to assess pelvis and hip angles, hip moment, and hip power. A Trendelenburg gait was defined as positive when nonoperative pelvic descent occurred at 30 % of the gait cycle, equivalent to mid-stance. Patients were classified into Trendelenburg gait-positive and -negative groups for statistical analysis. Unpaired t-test and chi-square test were used to compare the two groups. Multiple regression analysis was conducted to identify factors associated with the presence of a Trendelenburg gait. Results: A Trendelenburg gait was observed in 24 patients (27 %). Multiple regression analysis indicated that abduction (p < 0.01) and extension (p = 0.03) of hip joint power were significant determining of a Trendelenburg gait. Patients with a Trendelenburg gait exhibited reduced eccentric contraction of the hip abductor muscles and decreased concentric contraction of hip extensor muscles during early to mid-stance of their gait. Conclusion: Centrifugal contraction of hip abductor muscles and diminished eccentric contractility of hip extensor muscles appear crucial for hip stabilization mechanisms during gait after THA.

Cancer risk assessment of premalignant breast tissues from patients with BRCA mutations by genome profiling.

Patients with germline pathogenic variants of BRCA1/2 genes have a particular predisposition to develop breast cancer. No clinical test has been developed to accurately and quantitatively evaluate their risk of developing breast cancer. We hypothesized that aberrant cell clonal expansion may be initiated in normal breast tissues without manifesting pathologic changes. To assess the prevalence of clonal expansion in the normal breast, we collected normal breast tissue from 24 breast cancer patients who had undergone surgical resection and 5 carriers of pathogenic BRCA1/2 variant who had undergone prophylactic mastectomy. Whole-exome sequencing (WES) was conducted in 97 specimens from 14 individuals, and TOP panel, a gene panel targeting 464 genes, was conducted in 321 specimens from 26 individuals, including 8 individuals with germline pathogenic variants of BRCA1/2 genes. Recurrent oncogenic mutations within PIK3CA, ARHGAP35, HRAS, and NF1 were identified in normal breast tissue at considerable variant allelic frequencies (VAF), suggesting clonal expansion. In addition, 937 normal breast tissues were evaluated using the Breast Cancer Panel (BCP) targeting 25 genes to determine the exact prevalence and distribution of clonal expansion. To assess the clonal expansion, we developed the clonality score, which is the mean value of clonal cell fractions for samples obtained from a given breast. The average clonality score in macroscopically normal breast tissue was 0.95 (0-2.46), with a significant difference between cases with and without a history of breast cancer of stage 2 or more advanced stage (p = 0.01). Additional WES on 42 samples with relatively large clone size (VAF > 3%) confirmed that these cell clones harbored multiple mutations (10.7 mutations/sample), and the number of existing mutations was consistent with the clone size (R = 0.50). The results suggest that clonal changes occur in normal breast tissue of women at high risk for breast cancer even before cancer is detected pathologically and/or radiologically, and the clonality score shows the potential to be a valid method of evaluating clonal expansion for cancer-risk assessment that provides appropriate preventive options for patients at high risk for breast cancer.

PRAME expression in fibrosarcomatous dermatofibrosarcoma protuberans.

PRAME (PReferentially expressed Antigen in MElanoma) was first identified as a malignant melanoma-specific antigen. Recently, a few cases of fibrosarcomatous dermatofibrosarcoma protuberans (FS-DFSP) were shown to have positivity for PRAME, while conventional dermatofibrosarcoma protuberans (C-DFSP) was negative. Because PRAME may be of diagnostic utility in FS-DFSP and is raising expectations as a new immunotherapy target, we examined the positivity of PRAME in FS-DFSP. Twenty-one cases of FS-DFSP and age/sex/location-matched cases of C-DFSP as a control group were examined by immunohistochemistry for CD34 and PRAME. The results were then evaluated by H-score, which was objectively and semi-quantitatively calculated using the open-source bioimaging analysis software QuPath. The results revealed that the PRAME H-score in FS-DFSP was significantly higher than that in C-DFSP (p = 0.0137). As for CD34, the H-score in FS-DFSP was significantly lower than that in C-DFSP (p < 0.001). Using these two immunohistochemical analyses in combination, the sensitivity and specificity for the diagnosis of FS-DFSP were 86% and 90%, respectively. Double staining of CD34 and PRAME revealed that PRAME-positive and CD34-positive areas did not overlap. This is the largest study to examine PRAME expression in FS-DFSP, and it confirmed the usefulness of PRAME in diagnosing this condition.

Impact of COVID-19 pandemic on bone and soft tissue sarcoma patients' consultation and diagnosis.

The coronavirus disease (COVID-19) pandemic negatively affected the diagnosis and treatment of several cancer types. However, this pandemic's exact impact and extent on bone and soft tissue sarcomas need to be clarified. We aimed to investigate the effect of the COVID-19 pandemic and emergency declaration by the local government on consultation behavior and clinical stage at diagnosis of bone and soft tissue sarcoma. A total of 403 patients diagnosed with bone and soft tissue sarcoma who initially visited three sarcoma treatment hospitals between January 2018 and December 2021 were included. The monthly number of newly diagnosed soft tissue sarcoma patients was reduced by 25%, and the proportion of soft tissue patients with stage IV disease at diagnosis significantly increased by 9% during the COVID-19 pandemic compared to before the COVID-19 pandemic. Furthermore, the monthly number of new primary bone and soft tissue sarcoma patients significantly decreased by 43% during the state of emergency declaration. The COVID-19 pandemic had a negative impact on soft tissue sarcoma patients' consultation behavior and increased the proportion of advanced-stage patients at initial diagnosis. An emergency declaration by the local government also negatively affected primary bone and soft tissue sarcoma patients' consultation behavior.

Controlling the pore size of carbonate apatite honeycomb scaffolds enhances orientation and strength of regenerated bone.

To restore functions of long bones and avoid reconstruction failure, segmental defects should be quickly repaired using abundant amounts of regenerated bone with high mechanical strength and orientation along the bone axis. Although both bone volume and bone matrix orientation are important for faster restoration of long bones with segmental defects, researchers have primarily focused on the former. Artificial bone scaffolds with uniaxial channels, (e.g., honeycomb (HC) scaffolds), are considered adequate for regenerating bone oriented along the bone axis. The channel size may affect the orientation, amount, and strength of the regenerated bone. In this study, we investigated the effects of channel size in carbonate apatite HC scaffolds on the orientation of bones regenerated in segmental bone defects and determined the adequate channel size. Carbonate apatite HC scaffolds, with different channel sizes (350, 550, 730, and 890 µm in length on the side of the square aperture), were fabricated by extrusion molding of a mixture of calcium carbonate and organic binder, debinding, and subsequent phosphatization to convert the composition from calcium carbonate to carbonate apatite. No significant difference in the amounts of regenerated bones was observed for different channel sizes. However, bone along the bone axis was formed in the channels ≤550 µm in size but not in channels ≥730 µm. The HC scaffolds with a channel size of 350 µm regenerated bone with higher bending strength than those with a channel size of 890 µm. However, bone regenerated with the HC scaffolds having channel sizes of 350, 550, and 730 µm showed equal bending strength. Thus, the adequate channel size for fast regeneration of high-strength bone, oriented to the bone axis, is ≤730 µm. To the best of our knowledge, this is the first study to report the effect of channel size on bone orientation and strength. The findings of this study are relevant to the fast repair of segmental bone defects.

Pre- and postoperative Coronal Plane Alignment of the Knee classification and its impact on clinical outcomes in total knee arthroplasty.

Aims: The Coronal Plane Alignment of the Knee (CPAK) classification has been developed to predict individual variations in inherent knee alignment. The impact of preoperative and postoperative CPAK classification phenotype on the postoperative clinical outcomes of total knee arthroplasty (TKA) remains elusive. This study aimed to examine the effect of postoperative CPAK classification phenotypes (I to IX), and their pre- to postoperative changes on patient-reported outcome measures (PROMs). Methods: A questionnaire was administered to 340 patients (422 knees) who underwent primary TKA for osteoarthritis (OA) between September 2013 and June 2019. A total of 231 patients (284 knees) responded. The -Knee Society Score 2011 (KSS 2011), Knee injury and Osteoarthritis Outcome Score-12 (KOOS-12), and Forgotten Joint Score-12 (FJS-12) were used to assess clinical outcomes. Using preoperative and postoperative anteroposterior full-leg radiographs, the arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) were calculated and classified based on the CPAK classification. To investigate the impact on PROMs, multivariable regression analyses using stepwise selection were conducted, considering factors such as age at surgery, time since surgery, BMI, sex, implant use, postoperative aHKA classification, JLO classification, and changes in aHKA and JLO classifications from preoperative to postoperative. Results: The preoperative and postoperative CPAK classifications were predominantly phenotype I (155 knees; 55%) and phenotype V (73 knees; 26%), respectively. The change in the preoperative to postoperative aHKA classification was a significant negative predictive factor for KOOS-12 and FJS-12, while postoperative apex proximal JLO was a significant negative predictive factor for KSS 2011 and KOOS-12. Conclusion: In primary TKA for OA, preoperative and postoperative CPAK phenotypes were associated with PROMs. Alteration in varus/valgus alignment from preoperative to postoperative was recognized as a negative predictive factor for both KOOS-12 and FJS-12. Moreover, the postoperative apex proximal JLO was identified as a negative factor for KSS 2011 and KOOS-12. Determining the target alignment for each preoperative phenotype with reproducibility could improve PROMs.

Robotic Arm-Assisted System Improved Accuracy of Cup Position and Orientation in Cementless Total Hip Arthroplasty for Dysplastic Hips: A Comparison Among Groups With Manual Placement, Computed Tomography-Based Navigation, and Robotic Surgery.

Background: Accurate cup placement in total hip arthroplasty (THA) for patients with dysplasia is challenging due to the distinctive bone deformities. This study aimed to compare the accuracy of cup placement position and orientation across robotic arm-assisted systems (R-THA), computed tomography-based navigation (N-THA), and manual procedure (M-THA) in THA for osteoarthritis secondary to dysplasia. Methods: A total of 167 patients (197 hips), including 88 R-THAs, 45 N-THAs, and 46 M-THAs, were analyzed. Propensity score matching was performed to align the patient backgrounds. Horizontal and vertical centers of rotation were measured for cup position, whereas radiographic inclination and anteversion were measured for cup orientation. The proportion of cases with cup placement within 3 mm and 5° from the target was compared. Results: R-THA had a significantly higher percentage of cup placement within 3 mm of the target compared to N-THA (78% vs 49%; P = .0041) and M-THA (78% vs 53%; P = .013). Similarly, R-THA was significantly more successful in placing the cup within 5° of the target compared to N-THA (84% vs 58%; P = .0049) and M-THA (91% vs 20%; P < .0001). Moreover, N-THA was significantly better at placing the cup within 5° of the target compared to M-THA (62% vs 14%; P < .0001), whereas there was no significant difference in the percentage of cup placement within 3 mm of the target (51% vs 51%; P = 1.0). Conclusions: Robotic arm-assisted system and computed tomography-based navigation improved accuracy in cup orientation compared to the manual procedure. Additionally, the robotic arm-assisted system further improved cup position accuracy.

Geriatric nutritional risk index as a predictor for surgical site infection in malignant musculoskeletal tumours of the trunk.

BACKGROUND AND OBJECTIVE: Surgical site infection (SSI) is common in surgery for malignant musculoskeletal tumours, specifically those arising from the trunk. In this study, we investigated the risk factors for SSI after resection of musculoskeletal tumours of the trunk. METHODS: This retrospective observational study included 125 patients (72 males, 53 females) with musculoskeletal tumours of the trunk in our hospital from 1 April 2008 to 31 August 2023. The incidence of SSI and its risk factors were investigated. RESULTS: SSI was observed in 26% (32/125), and the median time to SSI was 22 days. On multivariate analysis, the following were identified as risk factors for SSI: tumours arising caudal to Jacoby's line (hazard ratio [HR] 4.04; P = .0107), soft tissue reconstruction (HR 3.43; P = .0131), and low Geriatric Nutritional Risk Index (GNRI) (HR 0.96; P = .0304). Patients were classified into two risk categories based on GNRI scores: the risk group (GNRI ≤98) and no risk group (>98). The risk group showed a significantly lower overall noninfection survival rate (P = .023). CONCLUSION: Tumours arising caudal to Jacoby line, soft tissue reconstruction, and lower GNRI were risk factors for SSI. Preoperative and postoperative nutritional interventions should be considered to improve GNRI.

Association of sarcopenia with regional brain atrophy and white matter lesions in a general older population: the Hisayama Study.

Sarcopenia has been reported to be associated with cognitive decline and the risk of dementia. However, few studies have addressed the association between sarcopenia and brain morphological changes in the general population. A total of 1373 community-dwelling participants aged ≥ 65 years underwent brain MRI. Sarcopenia was defined based on the Asian Working Group for Sarcopenia's criteria. The pattern of regional gray matter volume loss associated with sarcopenia were assessed using a voxel-based morphometry (VBM) analysis. Regional brain volumes, intracranial volumes (ICV), and white matter lesions volumes (WMLV) were also measured using FreeSurfer. An analysis of covariance was used to examine the associations of sarcopenia with regional brain volumes in proportion to ICV. Of the participants, 112 had sarcopenia. The participants with sarcopenia had significantly lower total brain volume/ICV and total gray matter volume/ICV and higher WMLV/ICV than those without sarcopenia after adjusting for confounders. In VBM, sarcopenia was associated with lower gray matter volume in the frontal lobe, insula, cingulate gyrus, hippocampus, amygdala, and basal ganglia. Using FreeSurfer, we confirmed that the participants with sarcopenia had significantly lower frontal, insular, cingulate, and hippocampal volumes than those without sarcopenia. The current study showed that participants with sarcopenia had significantly lower volume in the frontal lobe, insula, cingulate, and hippocampus and higher WMLV than participants without sarcopenia. As these brain regions are likely to play an important role in cognitive function, these changes may suggest a shared underlying mechanism for the progression of sarcopenia and cognitive decline.

Component rotational mismatch in the standing position is a potential risk factor for unfavourable functional outcomes after total knee arthroplasty.

Purpose: This study assessed rotational mismatch between components after total knee arthroplasty (TKA) in the supine and standing positions and aimed to investigate the effect of rotational mismatch in the standing position on postoperative patient-reported outcome measures (PROMs). Methods: Seventy-one patients (71 knees) who underwent TKA for medial knee osteoarthritis were used to investigate rotational mismatches between components. Rotational mismatches between components were examined on postoperative standing whole-leg and supine knee radiographs using a three-dimensional-to-two-dimensional model image registration technique, and the angles between the reference axes of the components were measured. Component alignment was evaluated using postoperative computed tomography images, and a questionnaire (2011 version of the Knee Society Score: [KSS 2011]) was mailed to investigate postoperative PROMs. Results: In the entire cohort, rotational mismatches in the supine and standing positions were similar (p = 0.9315). In 15% of patients, the mismatch was large (>5°) in the supine position but small (<5°) in the standing position (overestimated group). However, in 23% of patients, the mismatch was small (<5°) in the supine position and large (>5°) in the standing position (underestimated group). The underestimated group had severe preoperative varus deformity, resulting in external rotation of both femoral and tibial components. Rotational mismatch in the standing position (p = 0.0032) was a significant risk factor for unfavourable PROMs. Patients with a mismatch in the standing position had significantly lower scores than those without a mismatch (p = 0.0215), exceeding the minimal clinically important difference values. Conclusions: The underestimated group is clinically important because the surgical procedure and intraoperative assessment of component placement are performed in the supine position. In cases of severe preoperative varus deformity, care should be taken not to place the component in malrotation to avoid rotational mismatch in the standing position. Level of Evidence: Ⅳ, Case series.

Can necrotic depth be a substitute of necrotic volume to predict collapse progression in osteonecrosis of the femoral head?

OBJECTIVE: Although some patients may experience collapse progression while others may not in post-collapse osteonecrosis of the femoral head (ONFH) with a necrotic lesion located within the weight-bearing part of the acetabulum (Type B/C1), few studies have focused on the natural course after collapse. This study aimed to clarify the correlation between necrotic volume (NV) and necrotic depth (ND) in predicting collapse progression in patients with post-collapse ONFH Type B/C1. MATERIALS AND METHODS: We retrospectively reviewed 54 hips with post-collapse ONFH Type B/C1 from 52 consecutive patients who were conservatively followed up for more than 1 year. We measured the amount of femoral head collapse using biplane radiographs at each follow-up period, and produced Kaplan-Meier survival curves with collapse progression (≥ 1 mm) as the endpoint. We compared NV and ND, which were calculated as the ratio of the distance from the articular surface of the femoral head to the deepest point of a necrotic lesion to the femoral head diameter in the mid-coronal slice of T1-weighted magnetic resonance imaging (MRI). RESULTS: We observed collapse progression in 31 hips (57.4%). The NV and ND were significantly greater in hips with collapse progression than in those without collapse progression (p = 0.0127 and 0.0047, respectively). Necrotic volume was significantly correlated with ND　(rs = 0.56, p < 0.0001). CONCLUSION: This study suggests that necrotic depth on the mid-coronal slice of T1-weighted MRI can be a substitute for necrotic volume to predict collapse progression in ONFH Type B/C1.

Expression of Forkhead Box M1 and Anticancer Effects of FOXM1 Inhibition in Epithelioid Sarcoma.

Epithelioid sarcoma (ES) is a rare aggressive sarcoma that, unlike most soft-tissue sarcomas, shows a tendency toward local recurrence and lymph node metastasis. Novel antitumor agents are needed for ES patients. Forkhead box transcription factor 1 (FOXM1) is a member of the Forkhead transcription factor family and is associated with multiple oncogenic functions; FOXM1 is known to be overexpressed and correlated with pathogenesis in various malignancies. In this study, we immunohistochemically analyzed FOXM1 expression levels and their clinical, clinicopathologic, and prognostic significance in 38 ES specimens. In addition, to investigate potential correlations between FOXM1 downregulation and oncologic characteristics, we treated ES cell lines with thiostrepton, a naturally occurring antibiotic that inhibits both small interfering RNA (siRNA) and FOXM1. In the analyses using ES samples, all 38 specimens were diagnosed as positive for FOXM1 by immunohistochemistry. We separated specimens into high (n = 19) and low (n = 19) FOXM1-protein expression groups by staining index score, and into large (n = 12), small (n = 25), and unknown (n = 1) tumor-size groups using a cutoff of 5 cm maximum diameter. Although there were significantly more samples with high FOXM1 expression in the large tumor group (P = .013), there were no significant differences with respect to age (P = 1.00), sex (P = .51), primary site of origin (P = .74), histologic subtypes (P = 1.00), depth (P = .74), or survival rate (P = .288) between the high and low FOXM1-protein expression groups. In the in vitro experiments using ES cell lines, FOXM1 siRNA and thiostrepton successfully downregulated FOXM1 mRNA and protein expression. Furthermore, downregulation of FOXM1 inhibited cell proliferation, drug resistance against chemotherapeutic agents, migration, and invasion and caused cell cycle arrest in the ES cell lines. Finally, cDNA microarray analysis data showed that FOXM1 regulated cIAP2, which is one of the apoptosis inhibitors activated by the TNFα-mediated NF-κB pathway. In conclusion, the FOXM1 gene may be a promising therapeutic target for ES.

Interlocking Open-Wedge Distal Tibial Tuberosity Osteotomy: Stabilizing Technique in the Retro-Tubercle Without Complementary Screw Fixation.

We present a knee osteotomy procedure that we have termed the interlocking open-wedge distal tibial tuberosity osteotomy. In this context, the term interlocking pertains to the manner in which the repositioned segments of the retro-tubercle seamlessly fit together as the transverse osteotomy opens to the intended corrective angle. This interlocking mechanism, serving as a distinctive feature, engenders a stable retro-tubercle configuration resembling a mortise-and-tenon joint. The distal end of the tibial tuberosity fits snugly behind the tibial diaphysis, augmenting stability and promoting the healing process. Consequently, poor union of the retro-tubercle caused by the widening of the retro-tubercle gap and an increase in posterior tibial slope are effectively prevented. In addition, the need for complementary hardware such as anteroposterior screw fixation, which is used to secure the retro-tubercle during the healing process, is notably eliminated. This elimination not only simplifies the surgical procedure but also eliminates potential complications that could arise from its use.

Continuous co-prescription of rebamipide prevents upper gastrointestinal bleeding in NSAID use for orthopaedic conditions: A nested case-control study using the LIFE Study database.

BACKGROUND: Rebamipide has been widely co-prescribed with non-steroidal anti-inflammatory drugs (NSAIDs) in Japan for decades. This study aimed to evaluate the effectiveness of rebamipide in preventing upper gastrointestinal bleeding in new users of NSAIDs without risk factors of NSAID-induced ulcers other than age. METHODS: A nested case-control study was conducted using medical claims data of 1.66 million inhabitants of 17 municipalities participating in Japan's Longevity Improvement & Fair Evidence study. The cohort entry (t0) corresponded to a new user of NSAIDs for osteoarthritis or low back pain. Patients with risk factors of NSAID-induced ulcers other than age were excluded. Cases were defined as patients who underwent gastroscopy for upper gastrointestinal bleeding (occurrence date was defined as index date). A maximum of 10 controls were selected from non-cases at the index date of each case by matching sex, age, follow-up time, and type and dosage of NSAIDs. Exposure to rebamipide was defined as prescription status from t0 to index date: Non-user (rebamipide was not co-prescribed during the follow-up period), Continuous-user (rebamipide was co-prescribed from t0 with the same number of tablets as NSAIDs), and Irregular-user (neither Non-user nor Continuous-user). Conditional logistic regression analysis was conducted to estimate each category's odds ratio compared to non-users. FINDINGS: Of 67,561 individuals who met the inclusion criteria, 215 cases and 1,516 controls were selected. Compared with that of Non-users, the odds ratios and 95% confidence interval were 0.65 (0.44-0.96) for Continuous-users and 2.57 (1.73-3.81) for Irregular-users. CONCLUSIONS: Continuous co-prescription of rebamipide significantly reduced the risk of upper gastrointestinal bleeding in an Asian cohort of new users of NSAIDs with osteoarthritis or low back pain without risk factors other than age.

Risk factor analysis of vertebral fractures requiring surgery in patients with ankylosing spondylitis.

OBJECTIVES: This study aimed to determine the risk factors for vertebral fractures requiring surgery in patients with ankylosing spondylitis (AS). METHODS: We included 60 patients with AS diagnosed by using the modified New York criteria and who were treated in our department from April 2004 to March 2019. We evaluated age, sex, disease duration, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), ankylosed sacroiliac joint, bamboo spine, number of ankylosed vertebrae, and treatment (nonsteroidal antiinflammatory drugs (NSAIDs)), prednisolone (PSL), conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), biological disease-modifying antirheumatic drugs (bDMARDs), spine surgery for vertebral fracture) at the final follow-up of the nonsurgical group and the preoperative follow-up of the surgical group. RESULTS: At the final follow-up, the mean age was 49 years, 46 patients (75%) were male, and the mean disease duration was 27 years. Additionally, 8 (13.3%) and 43 patients (71%) underwent surgical and medical treatments, respectively. The group of surgery for vertebral fracture had significantly higher CRP levels, which was also significantly associated with vertebral fracture surgery by multivariate analysis. CONCLUSIONS: CRP was identified as a risk factor for vertebral fractures requiring surgery. Control of systemic inflammation in patients with AS may reduce the risk of vertebral fractures requiring surgery.

Changing trends in traumatic spinal cord injury in an aging society: Epidemiology of 1152 cases over 15 years from a single center in Japan.

Traumatic spinal cord injury (TSCI) causes an insult to the central nervous system, often resulting in devastating temporary or permanent neurological impairment and disability, which places a substantial financial burden on the health-care system. This study aimed to clarify the up-to-date epidemiology and demographics of patients with TSCI treated at the largest SCI center in Japan. Data on all patients admitted to the Spinal Injuries Center with TSCI between May 2005 and December 2021 were prospectively collected using a customized, locally designed SCI database named the Japan Single Center Study for Spinal Cord Injury Database (JSSCI-DB). A total of 1152 patients were identified from the database. The study period was divided into the four- or five-year periods of 2005-2009, 2010-2013, 2014-2017, and 2018-2021 to facilitate the observation of general trends over time. Our results revealed a statistically significant increasing trend in age at injury. Since 2014, the average age of injury has increased to exceed 60 years. The most frequent spinal level affected by the injury was high cervical (C1-C4: 45.8%), followed by low cervical (C5-C8: 26.4%). Incomplete tetraplegia was the most common cause or etiology category of TSCI, accounting for 48.4% of cases. As the number of injuries among the elderly has increased, the injury mechanisms have shifted from high-fall trauma and traffic accidents to falls on level surfaces and downstairs. Incomplete tetraplegia in the elderly due to upper cervical TSCI has also increased over time. The percentage of injured patients with an etiology linked to alcohol use ranged from 13.2% (2005-2008) to 19% (2014-2017). Given that Japan has one of the highest aging populations in the world, epidemiological studies in this country will be very helpful in determining health insurance and medical costs and deciding strategies for the prevention and treatment of TSCI in future aging populations worldwide.

Development of an automatic surgical planning system for high tibial osteotomy using artificial intelligence.

BACKGROUND: This study proposed an automatic surgical planning system for high tibial osteotomy (HTO) using deep learning-based artificial intelligence and validated its accuracy. The system simulates osteotomy and measures lower-limb alignment parameters in pre- and post-osteotomy simulations. METHODS: A total of 107 whole-leg standing radiographs were obtained from 107 patients who underwent HTO. First, the system detected anatomical landmarks on radiographs. Then, it simulated osteotomy and automatically measured five parameters in pre- and post-osteotomy simulation (hip knee angle [HKA], weight-bearing line ratio [WBL ratio], mechanical lateral distal femoral angle [mLDFA], mechanical medial proximal tibial angle [mMPTA], and mechanical lateral distal tibial angle [mLDTA]). The accuracy of the measured parameters was validated by comparing them with the ground truth (GT) values given by two orthopaedic surgeons. RESULTS: All absolute errors of the system were within 1.5° or 1.5%. All inter-rater correlation confidence (ICC) values between the system and GT showed good reliability (>0.80). Excellent reliability was observed in the HKA (0.99) and WBL ratios (>0.99) for the pre-osteotomy simulation. The intra-rater difference of the system exhibited excellent reliability with an ICC value of 1.00 for all lower-limb alignment parameters in pre- and post-osteotomy simulations. In addition, the measurement time per radiograph (0.24 s) was considerably shorter than that of an orthopaedic surgeon (118 s). CONCLUSION: The proposed system is practically applicable because it can measure lower-limb alignment parameters accurately and quickly in pre- and post-osteotomy simulations. The system has potential applications in surgical planning systems.

Life Course Epidemiology of Hip Osteoarthritis in Japan: A Multicenter, Cross-Sectional Study.

BACKGROUND: The incidence of developmental dysplasia of the hip (DDH) in Japanese newborns has reduced drastically following a primary prevention campaign initiated around 1972 to 1973; this perinatal education campaign promoted maintaining the hips of newborns in the naturally flexed-leg position. The purpose of the present study was to describe the life course epidemiology of hip osteoarthritis (OA) in adolescent and adult patients and to assess its association with exposure to the primary prevention campaign for DDH. METHODS: We included new patients with hip OA diagnosed from January 1, 2022, to December 31, 2022, at 12 core hospitals (8 special-function hospitals and 4 regional medical care support hospitals). The trend in the percentage of hips with a history of DDH treatment in childhood was estimated with use of a centered moving average using the birth year of the patient. We compared the prevalence of severe subluxation (Crowe type II, III, or IV) between patients with secondary hip OA due to hip dysplasia who were born in or before 1972 and those who were born in or after 1973. RESULTS: Overall, 1,095 patients (1,381 hips) were included. The mean age at the time of the survey was 63.5 years (range, 15 to 95 years). A total of 795 patients (1,019 hips; 73.8% of hips) were diagnosed with secondary OA due to hip dysplasia. Approximately 13% to 15% of hips among patients born from 1963 to 1972 had a history of DDH treatment in childhood; however, the percentage decreased among patients born in or after 1973. The prevalence of severe subluxation (Crowe type II, III, or IV) among patients born in or after 1973 was 2.4%, which was significantly less than that among patients born in or before 1972 (11.1%; odds ratio, 0.20; p < 0.001). CONCLUSIONS: As of 2022, secondary hip OA due to hip dysplasia is still responsible for most new cases of adolescent and adult hip OA seen in core hospitals in Japan. However, the perinatal education campaign initiated 50 years ago, which utilized a population approach and advocated for maintaining the hips of newborns in the naturally flexed-leg position, may have improved the environmental factors of DDH, as indicated by the apparently reduced need for treatment of DDH in childhood and the associated severe subluxation. This may result in a reduced need for challenging hip surgery later in life. LEVEL OF EVIDENCE: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Small change in the arithmetic hip-knee-ankle angle during unicompartmental knee arthroplasty improves early postoperative functional outcomes.

INTRODUCTION: The optimal lower-limb alignment after unicompartmental knee arthroplasty (UKA) remains controversial. This study aimed to investigate the optimal lower-limb alignment for functional improvement in the early post-UKA period. We hypothesized that a small change (Δ) in the arithmetic hip-knee-ankle (aHKA) angle during surgery would result in better postoperative knee function. MATERIALS AND METHODS: This single-centered, retrospective study analyzed 91 patients (91 knees) who underwent UKA from April 2021 and December 2022. Preoperative and postoperative standing whole-leg radiographs were used to evaluate the mechanical HKA angle and aHKA angle. The aHKA angle was calculated from the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). We defined restored aHKA angle as a postoperative aHKA angle within ± 3° of the preoperative aHKA angle. Functional improvement was evaluated using the preoperative and one-year postoperative Knee Society Scoring 2011 (KSS 2011). A multivariate regression analysis was performed to investigate the optimal lower-limb alignment for functional improvement. RESULT: Postoperative restored aHKA angle (p = 0.020) was the only significant factor for improved KSS 2011 scores. Postoperative restored aHKA angle was obtained in 64 patients (70%). ΔMPTA (p < 0.001) and ΔLDFA (p = 0.037) were significant factors associated with a postoperative restored aHKA angle. CONCLUSIONS: UKA restores the native knee, including resurfacing constitutional alignment and medial collateral ligament tension. Minimal change in the aHKA angle during UKA improves the functional outcomes of the knee during the early postoperative period, consistent with the minimally invasive surgical concept of UKA.