松本 卓巳

OBJECTIVE: Hallux rigidus (HR), a form of osteoarthritis (OA) affecting the first metatarsophalangeal joint, significantly impairs mobility and quality of life. Despite its clinical importance, large-scale epidemiological studies on radiographic HR prevalence and associated factors remain limited. This study investigated the radiographic prevalence of HR and its associated factors in a large, population-based Japanese cohort. DESIGN: Data were obtained from 1998 participants (654 men, 1344 women) in the fifth survey of the nationwide Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study. Non-weight-bearing dorsoplantar foot radiographs were assessed using the Hattrup and Johnson classification (grade 1: mild, grade 2: moderate, and grade 3: severe); HR was defined as grade ≥1. Multivariable logistic regression assessed associated factors, and the Cochran-Armitage trend test evaluated severity-related trends. RESULTS: The mean age was 64.2 ​± ​12.7 years. The overall HR prevalence was 23.5 ​% (25.1 ​% in men, 22.8 ​% in women), with no significant sex difference. Unilateral and bilateral HR were 6.6 ​% and 17.0 ​% of participants, respectively. HR was classified as mild (13.3 ​%), moderate (7.0 ​%), or severe (3.3 ​%). Multivariable analysis identified older age, coastal residence, gout history, and knee OA as independent factors associated with HR. HR severity showed significant linear trends with both gout and knee OA. CONCLUSIONS: This study determined the radiographic prevalence of HR of 23.5 ​% in a Japanese population. Independent factors associated with HR included older age, coastal residence, gout, and knee OA. Findings indicate that HR is multifactorial and highlight the need to explore geographic and lifestyle-related factors in addition to medical conditions.

OBJECTIVE: This study aimed to investigate whether discontinuation of biological or targeted synthetic antirheumatic disease-modifying drugs (bDMARDs or tsDMARDs) influences the incidence of postoperative complications in patients with rheumatoid arthritis (RA) undergoing orthopedic surgery. METHODS: A retrospective multicenter cohort study including patients receiving bDMARDs or tsDMARDs who underwent orthopedic surgery was conducted. Data collected encompassed the duration of drug discontinuation and postoperative adverse events, such as delayed wound healing, surgical site infection (SSI), disease flare-ups, and mortality. The association between drug discontinuation and these outcomes was analyzed. Multivariate analyses were conducted to identify potential risk factors for these events. RESULTS: A total of 2,060 cases were initially enrolled. After applying inclusion and exclusion criteria, data from 1,953 patients were analyzed. No significant differences were observed between the groups regarding delayed wound healing, SSI, or mortality. However, the incidence of disease flare-ups was substantially higher in the drug discontinuation group and in the interleukin (IL)-6 inhibitor group. Multivariate analysis identified that tumor necrosis factor α and IL-6 inhibitor use was associated with a higher risk of delayed wound healing relative to T-cell function modifiers. CONCLUSION: In orthopedic surgery for patients with RA, maintaining the standard or the half of administration interval of bDMARD appears safe in the preoperative period. However, the drug discontinuation may increase the risk of postoperative flare-ups, particularly with IL-6 inhibitors. In addition, T-cell function modifiers may be associated with a lower risk of delayed wound healing, suggesting their safety profile in this context.

OBJECTIVES: This study aimed to reveal the frontal plane relationship between the ground reaction force (GRF), hip center (HC), and Mikulicz line under various standing conditions and during gait. METHODS: A dual-design approach, combining a static experiment and gait-database analysis, was used. First, a static experiment was conducted with 10 healthy adults standing on force plates under five conditions: stance widths of 0, 5, 10, and 20 cm, and single-leg stance. Second, gait data from a public database (n = 162, age ≤50 years) were analyzed to calculate comparable parameters during the single stance phase. The GRF-HC distance and the angle between the GRF and the line through the center of pressure and HC (GRF-Mikulicz angle) were evaluated using analysis of variance. RESULTS: Both the GRF-HC distance and the GRF-Mikulicz angle significantly differed among the bipedal standing conditions, with smallest values at 20 cm (1.3 cm, 0.3°) and largest at 0 cm (7.3 cm, 4.8°). Values at 0 cm did not significantly differ from single-leg standing (8.8 cm, 5.8°), and both fell within the ranges observed during the single stance phase of gait (6.5-9.2 cm, 4.8°-6.7°). CONCLUSION: A 20 cm-stance width best aligns the GRF with Mikulicz line in static standing. Single-leg and closed-leg standing replicate GRF direction during gait. These findings may inform preoperative planning of total knee arthroplasty but require validation in larger and patient-based cohorts, given the small sample size and restriction to healthy subjects. This exploratory study should be interpreted with caution regarding direct clinical application.

BACKGROUND: Achieving precise three-dimensional reconstruction during foot and ankle corrective surgeries is challenging. Intraoperative plantar pressure measurement (IPPM) can help assess foot morphology and detect abnormal pressure distributions. We developed an IPPM system using a navigation to align the floor reaction force with the femoral head's center. This study evaluates its accuracy in anesthetized patients. PATIENTS AND METHODS: Fifteen patients undergoing lower limb surgery were enrolled. Plantar pressure was measured intraoperatively in the supine position and compared with preoperative standing measurements. Similarity was evaluated using normalized cross-correlation (NCC) and peak pressure site agreement across 12 predefined foot regions. RESULTS: The IPPM device replicated standing plantar pressure, with a mean NCC of 0.92 ± 0.1 and a peak pressure site agreement rate of 76.7 ± 37.2 %. CONCLUSIONS: The newly developed intraoperative plantar pressure-measuring device accurately replicates standing plantar pressure in anesthetized patients, offering potential for improving intraoperative assessments and corrective procedures.

BackgroundThe accessory navicular is a common anatomical variant of the foot that may become symptomatic and occasionally require treatment, particularly in younger individuals. Recent evidence indicates that accessory navicular may be associated with posterior tibial tendon dysfunction in middle-aged and elderly individuals, potentially affecting physical function. However, research on its impact in this demographic remains limited. This study aims to assess the epidemiology and impact of accessory navicular, particularly type 2, on physical function in the general population.MethodsData from the fifth Research on Osteoarthritis/Osteoporosis Against Disability (ROAD) study were analyzed, including foot radiographs and physical examinations from 1995 participants. The presence and type of accessory navicular were determined, and physical function was assessed through stabilometer measurements, walking speed tests, and locomotive syndrome risk tests. In addition, the relevant items related to balance and falls were extracted from the structured interviews and analyzed for the relationship with the accessory navicular.ResultsThe prevalence of accessory navicular was higher in females (49.9%) than in males (43.2%), with type 2 being the most frequent type. The analysis revealed a high degree of bilateral symmetry, with 79.5% of males and 76.7% of females showing the same type of accessory navicular or absence thereof on both sides. No significant differences were found in physical performance measurements between feet with and without type 2 accessory navicular. Notably, a higher history of falls was associated with bilateral type 2 accessory navicular.ConclusionsThis study provides insights into the prevalence and type distribution of accessory navicular in the general population. While type 2 accessory navicular did not show significant impacts on physical performance, its association with a history of falls suggests potential implications for dynamic balance ability, warranting further investigation.Levels of Evidence:Level III retrospective case-control study.

BACKGROUND: The etiology and treatment outcomes of hallux valgus (HV) are widely investigated. However, research on pain and its impact on quality of life (QOL) remains limited. This study aimed to examine the detailed characteristics of pain associated with HV and to assess how this pain impacts daily activities and QOL. METHODS: We conducted a large cross-sectional investigation, the Hallux Valgus and Pain Epidemiology Study, in Japan. A total of 1700 participants, aged ≥20 years, provided foot photographs and completed a self-administered questionnaire. The HV angle was measured using the submitted photographs. Propensity score matching for age and sex was performed to compare QOL outcomes, using the Self-Administered Foot Evaluation Questionnaire (SAFE-Q), between participants with and those without HV. RESULTS: Among the 1700 participants, 419 were diagnosed with HV. Those with HV exhibited lower QOL scores across all self-administered foot evaluation questionnaire subscales, including pain, physical functioning, social functioning, and footwear. Greater HV severity correlated with increased foot pain (33.6 % in mild and 57.1 % in severe cases) and reduced QOL. Pain was most common in the big toe in mild/moderate cases but shifted to the lesser toes and metatarsal regions in severe cases. Multivariate analysis revealed the HV angle, daily physical activity, and coexisting knee pain as significant factors associated with HV pain. CONCLUSIONS: HV severity is closely associated with pain and lower QOL, particularly in cases involving pain in the lesser toes and metatarsalgia. Identifying risk factors for HV pain can guide preventive measures and improve patient outcomes.

INTRODUCTION: Hallux valgus (HV) is a common foot deformity characterized by lateral deviation of the great toe. Despite known associations with gender, age, and footwear, the prevalence of HV and its associated risk factors in Japan remain unclear. We conducted the first-ever prospective population-based cohort study (HAPPI study) in Japan to elucidate the prevalence of HV and identify its associated risk factors. METHODS: HAPPI study is a prospective, population-based cohort conducted in Japan from 2020 to 2023. A total of 1499 participants aged 20 and older were included across seven geographic regions in this analysis. HV was objectively assessed using self-photographs, with a hallux valgus angle ≥15° defining the condition. Demographic, clinical, and footwear-related data were collected via questionnaires. Logistic regression analysis identified risk factors, calculating odds ratio (OR) and 95 % confidence interval (CI). RESULTS: The prevalence of HV was 23.5 %, with higher rates in women (31.6 %) than men (13.3 %). Age-specific prevalence rates among women increased from 20.0 % in their 20s to 48.0 % in those aged 80 years or older. Bilateral HV was observed in 12.4 % of participants (5.7 % in men, 17.7 % in women), while unilateral HV was observed in 11.1 % (7.5 % in men, 13.9 % in women). Logistic regression identified significant risk factors, including female gender (OR: 3.2, 95 % CI: 2.4-4.4) and age ≥60 years. High-heeled shoe use in the 20s (OR: 3.3, 95 % CI: 1.2-9.5) and very narrow toe-box shapes (OR: 2.5, 95 % CI: 0.98-6.5) were associated with HV. CONCLUSION: HAPPI study demonstrated that HV is prevalent in Japan, affecting nearly one in four individuals, with significantly higher rates in women and older adults. Early footwear choices, particularly the use of high-heeled and very narrow toe-box shoes, were strongly associated with HV.

INTRODUCTION: We developed a smartphone application capable of automatically measuring the hallux valgus angle (HVA) and various intermetatarsal angles by capturing radiographic images displayed on a monitor. This study aimed to evaluate the accuracy of these measurements using the application. METHODS: Three users-a board-certified orthopedic surgeon, a resident, and a nonhealthcare professional (Users 1, 2, and 3)-independently used the application to measure angles on 92 radiographs from 92 consecutive patients. Mean absolute errors (MAEs) between the application-based measurements and the median of manual measurements performed by three experienced foot and ankle surgeons using a DICOM viewer were calculated for each user. To evaluate whether the measurement errors were acceptably small, one-sided t-tests were conducted to determine whether the MAEs were significantly less than 3°. Differences in MAEs among the three users were also assessed using analysis of variance. RESULTS: The MAEs of HVA by the three users were 1.1°, 1.3°, and 1.4°, respectively, all significantly below the 3° threshold (95% CI upper limit; 1.2°, 1.5°, and 1.5°). Comparable accuracy was observed for intermetatarsal angles, which have slightly greater variability for more lateral metatarsals. All measurements met the accuracy criterion of < 3°, except for the intermetatarsal angles between the first and fifth metatarsals measured by the nonhealthcare user. No significant difference in MAE was found among users for HVA (p = 0.13), whereas significant differences were noted for some intermetatarsal angles. CONCLUSIONS: The developed smartphone application accurately measured the HVA and various intermetatarsal angles, with performance comparable to that of experienced foot and ankle surgeons. Importantly, sufficient accuracy was achieved even when used by individuals without clinical training. The application may be useful as a practical tool in clinical and research settings.

Recurrent hemarthrosis after total knee arthroplasty (TKA) is a rare but challenging complication, with an incidence ranging from 0.3% to 1.6%. Conservative treatment, including rest, joint aspiration, and oral tranexamic acid, is often the first-line approach, but approximately two-thirds of cases require more invasive procedures. Genicular artery embolization (GAE) has emerged as a promising alternative to synovectomy for refractory cases, offering high success rates with fewer complications. While most reports of GAE for recurrent hemarthrosis focus on patients with osteoarthritis, data on its use in patients with rheumatoid arthritis (RA) are scarce. We report a case of a 79-year-old woman with RA who presented with recurrent hemarthrosis 11 years after TKA. Despite conservative treatment, her hemarthrosis persisted. Angiography revealed three hypervascular areas supplied by branches of the superior lateral, superior medial, and middle genicular arteries. Embolization was successfully performed using gelatin sponge, resulting in complete symptom resolution without recurrence at the two-year follow-up. This case highlights the potential of GAE as a viable treatment option for recurrent hemarthrosis in patients with RA, particularly those with multiple bleeding sites or when synovectomy is unsuccessful or impractical. Careful evaluation from multiple angiographic angles is crucial to detect all bleeding sources, especially in post-TKA cases where metal implants may obscure vascular regions. Although further studies are needed, GAE may represent a safe and effective alternative for managing recurrent hemarthrosis in patients with RA.

BACKGROUND: Ankle arthritis significantly impacts a patient's quality of life, often necessitating surgical treatment in advanced cases. While ankle arthrodesis has been the standard procedure for decades, total ankle arthroplasty (TAA) has gained acceptance as a motion-preserving alternative. Although TAA adoption has expanded globally, data on trends and regional variations in Japan are limited. This study aimed to analyze the utilization and regional disparities in TAA and ankle arthrodesis over a 12-year period using a national database. METHODS: Data were retrospectively extracted from the Diagnosis Procedure Combination database, which includes over 50 % of inpatient admissions in Japan. Patients who underwent primary TAA or ankle arthrodesis for osteoarthritis or rheumatoid arthritis between 2010 and 2022 were included. Procedure counts, patient demographics, and regional variations were analyzed. Statistical methods included linear regression for trend analyses and exploration of factors influencing regional disparities, such as hospital volume and the number of members of the Japanese Society for Surgery of the Foot. RESULTS: From 2010 to 2022, 2461 TAA and 9415 ankle arthrodesis procedures were performed. TAA utilization increased 3.8-fold compared with a 1.4-fold increase in ankle arthrodesis. The proportion of TAA among ankle surgeries increased from 13.4 % to 30.2 %. TAA was performed more frequently in older patients and those with rheumatoid arthritis than ankle arthrodesis. Over the study period, the average age of TAA patients significantly increased, whereas the proportion of patients with rheumatoid arthritis decreased, reflecting a shift toward treating patients with osteoarthritis. Significant regional variations in TAA utilization were observed, primarily influenced by the availability of high-volume hospitals. CONCLUSIONS: TAA utilization has grown significantly in Japan, underscoring its acceptance as an alternative to ankle arthrodesis. However, access disparities persist, driven by the limited availability of high-volume hospitals. These findings highlight the need for improved access to TAA and the standardization of surgical practices to ensure equal treatment opportunities for patients with ankle arthritis.

CASE: We present a rare case of a 26-year-old woman with double checkrein deformity involving both the extensor and flexor tendons, secondary to compartment syndrome. The patient experienced hallux and lesser toe deformities, limiting mobility and causing painful callosities. Surgical correction involved the flexor hallucis longus tenotomy and the extensor hallucis longus and extensor digitorum longus tendon lengthening, leading to significant functional improvement and resolution of symptoms at 2-year follow-up. CONCLUSION: This case emphasizes the importance of recognizing double checkrein deformity, a rare condition involving both flexor and extensor tendons, to ensure appropriate diagnosis and optimal treatment outcomes.

OBJECTIVES: Rheumatoid arthritis often leads to debilitating damage in the elbow joint, which may require total elbow arthroplasty (TEA). The Kudo TEA is one of the unlinked type prostheses with reportedly favorable outcomes. However, there is limited information available regarding its long-term performance. This retrospective study aimed to evaluate the long-term survivorship and identify risk factors associated with failure of the Kudo Type-5 TEA in patients with rheumatoid arthritis (RA), specifically exceeding 10 years. METHODS: Patients with RA who underwent TEA with the Kudo Type-5 prosthesis from 1998 to 2009, with a minimum ten-year follow-up, were included. Failure, defined as revision surgery or radiographic loosening, was assessed using the Kaplan-Meier method. The patients' demographic data, radiographic measurements, range of motion, Mayo elbow performance score (MPES), and the material of the ulnar component were compared between the elbows with and without failure. Univariate analysis identified factors affecting long-term survivorship. RESULTS: Among 49 elbows in 38 patients with a mean follow-up of 13.4 years, significant improvements in flexion range and MPES were observed. The failure rate was 39%, occurring in 19 elbows. Among these failures, 13 cases were attributed to issues with the ulnar component, making it the most common cause. The overall survivorship rate of the Kudo Type-5 prosthesis at ten years was 78%, as calculated using the Kaplan-Meier method. Factors associated with a higher failure risk included a shorter duration from RA onset to surgery (17.2 ± 5.8 years vs. 23.3 ± 8.7 years; p = 0.01), a lower preoperative stability score of MPES (6.6 ± 4.1 vs. 9.3 ± 1.7; p < 0.01), larger implant deviation assessed by the implant deviation index (9.3 ± 1.3% vs. 5.4 ± 1.1%; p = 0.03), and the use of the all-polyethylene ulnar component (79.0% vs. 46.7%; p = 0.04). CONCLUSION: Although the Kudo Type-5 prosthesis demonstrated satisfactory results in patients with RA, failures occurred to some extent over a long-term follow-up period. Careful monitoring should be conducted, particularly in cases with a short duration from RA onset to surgery, preoperative instability, misalignment of the implant and the use of the all-polyethylene ulnar component.

OBJECTIVES: We developed the deep neural network (DNN) model to automatically measure hallux valgus angle (HVA) and intermetatarsal angle (IMA) on foot radiographs. The objective is to assess the accuracy of the model by comparing to the manual measurement of foot and ankle surgeons. MATERIALS AND METHODS: A DNN was developed to predict the bone axes of the first proximal phalanx and all metatarsals from the first to the fifth in foot radiographs. The dataset used for model development consisted of 1798 radiographs collected from a population-based cohort and patients at our foot and ankle clinic. The retrospective validation cohort comprised of 92 radiographs obtained from 92 consecutive patients visiting our foot and ankle clinic. The mean absolute error (MAE) between automatic measurements by the model and the median of manual measurements by three foot and ankle surgeons was compared to 3° using one-tailed t-test and was also compared to the inter-rater difference in manual measurements among the three surgeons using two-tailed paired t-test. RESULTS: The MAE for HVA was 1.3° (upper limit of 95% CI 1.6°), and this was significantly smaller than the inter-rater difference of 2.0 ± 0.2° among the surgeons, demonstrating the superior accuracy of the model. In contrast, the MAE for IMA was 0.8° (upper limit of 95% CI 1.0°) that showed no significant difference from the inter-rater difference of 1.0 ± 0.1° among the surgeons. CONCLUSION: Our model demonstrated the ability to measure the HVA and IMA with an accuracy comparable to that of specialists.

BACKGROUND: There is currently no deep neural network (DNN) capable of automatically classifying tibial sesamoid position (TSP) on foot radiographs. METHODS: A DNN was developed to predict TSP according to the Hardy and Clapham's classification. A total of 1554 foot radiographs were used for model development. The validation of the model was conducted using radiographs obtained from 113 consecutive first-visit patients of our foot and ankle clinic. On these 113 radiographs, TSP was independently classified by three foot and ankle surgeons and the DNN, and their results were compared. The weighted kappa value of TSP between the DNN prediction and the median of the three surgeons (KAI) was calculated. RESULTS: The KAI was 0.95 (95 %CI: 0.85- 1.00), indicating sufficient consistency between the surgeons and the DNN. CONCLUSIONS: We have developed a DNN for automated TSP classification that demonstrates sufficient consistency with foot and ankle surgeons. LEVELS OF EVIDENCE: Level 3 - Retrospective Cohort Study.

This study aims to investigate the influence of lumbar spine disorders on the development of asymmetric hallux valgus (HV). Data from the fifth survey of the Osteoarthritis/Osteoporosis Against Disability (ROAD) study, a nationwide prospective study in Japan, were analyzed. HV severity was categorized into 4 grades based on the radiographic HV angle, and asymmetric HV was defined as having at least one HV on either side, with a difference of two or more severity grades between the left and right. Controls were matched from both the Normal group (without HV on both sides) and the Symmetric group (HV on at least one side with a difference of one or less severity grades). Univariate analysis assessed lumbar conditions, and multinomial logistic regression analysis explored the association between lumbar spine disorders and asymmetric HV. Among 1997 participants, 27 had asymmetric HV. Univariate analysis revealed a higher incidence of L5 spondylolisthesis and scoliosis in the Asymmetric group. Multinomial logistic regression analysis revealed that scoliosis independently increased the likelihood of asymmetrical HV (Odds ratio [OR] = 3.586, 95%Confidence interval [CI] 1.111-11.582), but showed no significant impact on symmetrical HV (OR 0.910, 95% CI 0.355-2.334). Asymmetric HV is rare but may be associated with lumbar spine disorders, particularly scoliosis.

BACKGROUND: Janus kinase (JAK) inhibitors, such as baricitinib, are widely used to treat rheumatoid arthritis (RA). Clinical studies show that baricitinib is more effective at reducing pain than other similar drugs. Here, we aimed to elucidate the molecular mechanisms underlying the pain relief conferred by baricitinib, using a mouse model of arthritis. METHODS: We treated collagen antibody-induced arthritis (CAIA) model mice with baricitinib, celecoxib, or vehicle, and evaluated the severity of arthritis, histological findings of the spinal cord, and pain-related behaviours. We also conducted RNA sequencing (RNA-seq) to identify alterations in gene expression in the dorsal root ganglion (DRG) following baricitinib treatment. Finally, we conducted in vitro experiments to investigate the direct effects of baricitinib on neuronal cells. RESULTS: Both baricitinib and celecoxib significantly decreased CAIA and improved arthritis-dependent grip-strength deficit, while only baricitinib notably suppressed residual tactile allodynia as determined by the von Frey test. CAIA induction of inflammatory cytokines in ankle synovium, including interleukin (IL)-1β and IL-6, was suppressed by treatment with either baricitinib or celecoxib. In contrast, RNA-seq analysis of the DRG revealed that baricitinib, but not celecoxib, restored gene expression alterations induced by CAIA to the control condition. Among many pathways changed by CAIA and baricitinib treatment, the interferon-alpha/gamma, JAK-signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) pathways were considerably decreased in the baricitinib group compared with the celecoxib group. Notably, only baricitinib decreased the expression of colony-stimulating factor 1 (CSF-1), a potent cytokine that causes neuropathic pain through activation of the microglia-astrocyte axis in the spinal cord. Accordingly, baricitinib prevented increases in microglia and astrocytes caused by CAIA. Baricitinib also suppressed JAK/STAT3 pathway activity and Csf1 expression in cultured neuronal cells. CONCLUSIONS: Our findings demonstrate the effects baricitinib has on the DRG in relation to ameliorating both inflammatory and neuropathic pain.

Symptomatic neuroma represents a debilitating complication after major limb amputation. The regenerative peripheral nerve interface (RPNI) has emerged as a reproducible and practical surgery aimed at mitigating the formation of painful neuroma. Although previous animal studies revealed axonal sprouting, elongation, and synaptogenesis of proximal nerve stump within the muscle graft in RPNI, there is a lack of reports confirming these physiological reactions at the histopathological level in human samples. This report presents a case of below-knee amputation with RPNI due to foot gangrene resulting from polyarteritis nodosa. Subsequently, an above-knee amputation was necessitated due to the exacerbation of polyarteritis nodosa, providing the opportunity for histopathological examination of the RPNI site. The examination revealed sprouting, elongation, and existence of neuromuscular junction of the tibial nerve within the grafted muscle. To the best of our knowledge, this is the first report demonstrating axonal sprouting, elongation, and possibility of synaptogenesis of the nerve stump within the grafted muscle in a human sample.

BACKGROUND: An association between the medial partite hallux sesamoid (MPHS) and hallux valgus (HV) has been suggested; however, a causal relationship has not been confirmed. This study aimed to determine their causal relationship using a cross-sectional radiographic survey of a large-scale population cohort covering a wide age group. PATIENTS AND METHODS: The fifth survey of the Research on Osteoarthritis/Osteoporosis against Disability study involved 1997 participants aged 21-95 years who had undergone anteroposterior radiography of bilateral feet. The presence of MPHS, its morphology, and radiographic parameters related to the HV were assessed using radiographs. Changes in the prevalence of MPHS with age were assessed using trend tests. The relationship between the MPHS and HV was assessed based on sex and age. RESULTS: MPHS was found in 508 out of 3994 feet (12.7 %), with a significant difference in prevalence between men and women (10.0 % vs. 13.7 %, p < 0.001). Trend analysis demonstrated a significant decrease in MPHS occurrence with age in both sexes. HV angle was significantly higher in feet with MPHS than in those without (Men: 17.8 ± 7.0° vs. 14.0 ± 5.9°, p < 0.0001; Women: 19.6 ± 7.7° vs. 17.7 ± 7.9°, p < 0.0001). The prevalence of HV angle ≥ 20° was also significantly higher in feet with MPHS than in those without (Men: 33.3 % vs. 14.6 %, p < 0.0001; Women: 46.5 % vs. 34.6 %, p < 0.0001). This association between MPHS and HV was noticeable in younger adults and became less prominent with age. CONCLUSIONS: MPHS is associated with HV. The weakening of this relationship and the decreased prevalence of MPHS with age suggest that MPHS is not caused by HV, but is one of the causes of HV, especially in younger adults.

OBJECTIVES: This study aimed to investigate the trend of joint destruction patterns on knee radiographs of patients with rheumatoid arthritis (RA) undergoing total knee arthroplasty (TKA) over the past 16 years. METHOD: Medial joint space, lateral joint space, medial spur area, lateral spur area (L-spur), and femoro-tibial angle were obtained from 831 preoperative knee radiographs of patients with RA who underwent TKA between 2006 and 2021 using software capable of automatic measurements. Non-hierarchical clustering was performed based on these five parameters. Trends in the five individual radiographic parameters and the ratio of each cluster were investigated during the target period. Moreover, clinical data from 244 cases were compared among clusters to identify factors associated with this trend. RESULTS: All parameters, except for L-spur, showed significant increasing trends from 2006 to 2021. The radiographs were clustered into groups according to the characteristic pattern of radiographic findings: cluster 1 (conventional RA type), with bicompartmental joint space narrowing (JSN), less spur formation, and valgus alignment; cluster 2 (osteoarthritis type), with medial JSN, medial osteophytes, and varus alignment; and cluster 3 (less destructive type), with mild bicompartmental JSN, less spur formation, and valgus alignment. The ratio of cluster 1 showed a significantly decreasing trend contrary to the significantly increasing trend in clusters 2 and 3. The DAS28-CRP of cluster 3 was higher than those of clusters 1 and 2. CONCLUSIONS: Radiographs of TKA recipients with RA are increasingly presenting osteoarthritic features in recent decades. Key Points • Using automated measurement software, morphological parameters were measured from radiographs of 831 patients with rheumatoid arthritis who had undergone TKA in the past 16 years. • Cluster analysis based on the radiographic parameters revealed that the radiographs of patients with end-stage knee arthritis requiring total knee arthroplasty were classified into three groups. • In patients with rheumatoid arthritis who have undergone total knee arthroplasty in the past 16 years, the proportion of clusters with features of osteoarthritis and difficult-to-treat rheumatoid arthritis has increased, while the proportion of conventional rheumatoid arthritis has decreased.

BACKGROUND: The present study aimed to investigate changes in hallux alignment after corrective surgery for adult-acquired flatfoot deformity (AAFD). PATIENTS AND METHODS: The present study retrospectively investigated the changes of hallux alignment in 37 feet (33 patients) which were treated with double or triple arthrodesis of the hindfoot for AAFD between 2015 and 2021 and could be followed up to one year postoperatively. RESULTS: Hallux valgus (HV) angle significantly decreased by a mean 4.1° among the whole 37 subjects and by a mean 6.6° among the 24 subjects who had a preoperative HV angle of 15° or more. Those who had HV correction (HV angle correction ≥ 5°) demonstrated more near-normal postoperative alignment of the medial longitudinal arch and hindfoot than those without HV correction. CONCLUSIONS: Hindfoot fusion for AAFD could improve preoperative HV deformity to some degree. HV correction was associated with proper realignment of the midfoot and hindfoot. LEVEL OF EVIDENCE: Level IV; retrospective case series.

To prevent postoperative complications in corrective surgery for foot deformities such as hallux valgus and pes planus, it is critical to quantitatively predict the postoperative standing-position plantar pressure distribution during the operation. The authors have previously proposed an intraoperative plantar pressure measurement system (IPPM) that allows for the measurement of a supine patient’s plantar pressure distribution that is equivalent to that in the standing position. This system consists of an IPPM device comprising of a force plate and pressure distribution sensor, an optical three-dimensional position measurement device, a navigation monitor, and a PC. The plantar pressure distribution in the standing position is reproduced by navigating the operator, as he or she presses the IPPM device against the patient’s sole so that the weight-bearing axis (floor reaction force vector) and femoral head center are as close to each other as possible. However, in our previous study, the reproducibility of the standing position plantar pressure distribution was insufficient. Therefore, in the present study, we add a navigational function that can be used to bring the centers of pressure in the standing position and under measurement, as well as to correct the IPPM’s self-weight in the measured force. The improved device was used in an experiment with nine healthy subjects, and the similarity of the plantar pressure distribution in the standing and supine positions was evaluated using normalized cross-correlation, yielding an average of 0.90. Furthermore, in an evaluation experiment with ten orthopedic surgeons, it was observed that using the system reproduced the plantar pressure distribution significantly better than when the system was not used. These results indicate that the present system can predict the plantar pressure distribution in the standing position. We believe that this system can contribute to reducing complications after foot surgery.

OBJECTIVES: The purpose of this study was to clarify the effect of gait protocols and postoperative shoes on forefoot load in preoperative patients for forefoot disorders and compare footwear comfort between different types of postoperative shoes. METHODS: Fourteen subjects scheduled to undergo forefoot surgeries were recruited. The maximum force under the forefoot region was measured during 10 m straight walking in two gait patterns with six different shoe types. Visual analogue scale (VAS) scores for footwear comfort, subjective lower thigh pain, and electrical activities of lower thigh muscles were also evaluated. RESULTS: The body weight-normalized maximum force under the forefoot region significantly decreased in step-to gait compared to normal gait regardless of the shoe types used. Under the same gait condition, no significant difference was observed in the forefoot off-loading effect between the different shoe types used. Significantly worse VAS scores, significantly higher tibialis anterior muscle activities, and complaints of lower thigh pain were demonstrated in the gait with the reverse camber shoe. CONCLUSIONS: Gait protocol of step-to gait had more forefoot off-loading effect than postoperative shoes. The forefoot off-loading effect did not differ among the postoperative shoes, suggesting that postoperative shoes can be selected with an emphasis on footwear comfort.

To investigate the trend and factors related to the occurrence of osteoarthritis (OA)-like features on knee radiographs of rheumatoid arthritis (RA) patients undergoing total knee arthroplasty (TKA) in the recent decades. To classify antero-posterior knee radiographs into 'RA' and 'OA-like RA' groups, a deep learning model was developed by training the network using knee radiographs of end-stage arthropathy in RA patients obtained during 2002-2005 and in primary OA patients obtained during 2007-2009. We used this model to categorize 796 knee radiographs, which were recorded in RA patients before TKA during 2006-2020, into 'OA-like RA' and 'RA' groups. The annual ratio of 'OA-like RA' was investigated. Moreover, univariate and multivariate analyses were performed to identify the factors associated with the classification as OA-like RA using clinical data from 240 patients. The percentage of 'OA-like RA' had significant increasing trend from 20.9% in 2006 to 67.7% in 2020. Higher body mass index, use of biologics, and lower level of C-reactive protein were identified as independent factors for 'OA-like RA'. An increasing trend of knee radiographs with OA-like features was observed in RA patients in the recent decades, which might be attributed to recent advances in pharmacotherapy.

We investigated the role of hematopoietically expressed homeobox protein (Hhex) in osteoclast development. Trimethylation of lysine 27 of histone H3 at the cis-regulatory element of Hhex was maintained and that of lysine 4 was reduced during receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis, which was associated with a reduction of Hhex expression. Overexpression of Hhex in bone marrow-derived macrophages inhibited, whereas Hhex suppression promoted, RANKL-induced osteoclastogenesis in vitro. Conditional deletion of Hhex in osteoclast-lineage cells promoted osteoclastogenesis and reduced cancellous bone volume in mice, confirming the negative regulatory role of Hhex in osteoclast differentiation. Expression of cyclin-dependent kinase inhibitors such as Cdkn2a and Cdkn1b in osteoclast precursors was negatively regulated by Hhex, and Hhex deletion increased the ratio of cells at the G1 phase of the cell cycle. In conclusion, Hhex is an inhibitor of osteoclast differentiation that is regulated in an epigenetic manner and regulates the cell cycle of osteoclast precursors and the skeletal homeostasis. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

BACKGROUND: There has been a paucity of literature revealing the discrepancy between self-recognition about hallux valgus (HV) and radiographically-evaluated foot configuration. Knowing this discrepancy will help to make a comparative review of the findings of previous literatures about epidemiological studies about the prevalence of HV. QUESTIONS/PURPOSES: (1) Is there a discrepancy between radiographically-assessed and self-recognized HV in the general population? (2) What factors affect the self-recognition of HV in the general population? METHODS: The fifth survey of the Research on Osteoarthritis/Osteoporosis against Disability study involved 1996 participants who had undergone anterior-posterior radiography of bilateral feet and answered a simple dichotomous questionnaire on self-recognition of HV. Measurements of the HV angle (HVA), interphalangeal angle of the hallux (IPA), and intermetatarsal angle between 1st and 2nd metatarsals (IMA) were performed using radiographs. Radiographic diagnosis of HV was done using the definition of hallux valgus angle of 20° or more. After univariate comparison of the participant backgrounds and radiographic measurements between participants with or without self-recognition of HV, multivariable logistic regression analysis was conducted in order to reveal independent factors affecting self-recognition. RESULTS: Significant difference was found between the prevalence of radiographically-assessed and self-recognized HV (29.8% vs. 16.5%, p <  0.0001). The prevalence of self-recognized HV increased with the progression of HV severity from a single-digit percentage (normal grade, HVA < 20°) up to 100% (severe grade, HVA ≥ 40°). A multivariable logistic regression analysis demonstrated that HVA, IMA, and female sex were independent positive factors for self-recognition of HV (HVA [per 1° increase]: OR, 1.18; 95% CI, 1.15-1.20; p <  0.0001; IMA [per 1° increase]: OR, 1.15; 95% CI, 1.09-1.20; p <  0.0001; and female sex [vs. male sex]: OR, 3.47; 95% CI, 2.35-5.18; p <  0.0001). CONCLUSIONS: There was a significant discrepancy between radiographically-assessed and self-recognized HV which narrowed with the progressing severity of HV. HVA, IMA, and female sex were independent positive factors for self-recognition of HV. Attention needs to be paid to potentially lowered prevalence of HV in epidemiological studies using self-reporting based on self-recognition.

BACKGROUND: Suture and staple fixations are commonly used methods for Akin osteotomy; however, there has been a paucity of studies comparing these methods without bias. PATIENTS AND METHODS: We retrospectively compared the outcomes of 58 Akin osteotomies performed by a single surgeon using suture fixation and 39 Akin osteotomies performed by the same surgeon using staple fixation during the same period. RESULTS: Bone union at the osteotomy site was achieved in all cases with no cases of complications related to the materials used. Occurrence of breakage of the lateral cortex of the proximal phalanx showed no significant difference between the suture and staple groups. The lateral cortex breakage produced greater instability at the osteotomy site with the staple fixation compared to the suture fixation. CONCLUSIONS: Comparison of suture and staple fixations of Akin osteotomy demonstrated the superiority of suture fixation against staple fixation in terms of stability and cost-efficiency.

Sagittal misalignment is a major cause of patient dissatisfaction and re-operation after first metatarsophalangeal (MTP) joint arthrodesis. The stereotypical application of the fixed angle would be undesirable, especially in cases of flat or cavus foot. We retrospectively reviewed 31 cases (27 patients) in which first MTP joint arthrodesis was performed using the flat cut joint preparation technique with reference to the plantar clearance beneath the pulp of the toe while simulating weightbearing by pushing a board against the sole. The most common underlying cause of surgery was rheumatoid arthritis (22 cases [71%]). Clinical outcomes were evaluated by the Japanese of Surgery of the Foot (JSSF) hallux scale and the self-administered foot evaluation questionnaire (SAFE-Q). Twenty-three cases were also examined by pedobarography to evaluate postoperative walking plantar pressure. At the most recent follow-up of a mean 19.6 months, the toe-to-floor distance of the hallux in static standing posture was a mean of 2.5 mm (range, 0-10 mm). All but 1 foot (97%) achieved bone union. There were no complications or revisions due to misalignment of the fused MTP joint. JSSF hallux scales improved significantly from 47 preoperatively to 82 postoperatively. All subscale scores except general health and well-being in the SAFE-Q improved significantly at final follow-up versus preoperative period. Plantar pressure under the hallux was correlated with the toe-to-floor distance but not radiographic parameter. In conclusion, first MTP joint arthrodesis achieved good clinical outcomes when using toe-to-floor distance and Kirschner wire template for flat cut joint preparation.

'Giving way' is a rapid inversion of the rear part of the foot, which does not result in an acute lateral ankle sprain. It is a specific event for patients with chronic ankle instability (CAI). This report described a 'giving way' in an 18-year-old female with CAI, which was biomechanically captured during walking on the flat surface. Shoes with unstable heel having a hemisphere rubber on the sole of the heel were used to provoke 'giving way'. To the authors' knowledge, this is the first report describing the kinetics of 'giving way' during walking. The event of 'giving way' was captured by an Inertial Motor Unit located on the dorsum of the foot and an insole-shaped plantar force measurement device. 'Giving way' provided distinctive data on both kinds of devices. Gyroscope data showed a rapid increase of inversion/plantarflexion/internal rotation (maximum levels: 204/280/346 degree/s) and following eversion/dorsiflexion/external rotation (maximum levels: 509/798/797 degree/s) of the foot segment at 350 ms - 492 ms after the heel strike. Plantar force data demonstrated the rapid decrease and subsequent recovery of the regional force on the head of 1st metatarsal head, suggesting a rapid inversion followed by the foot's defensive eversion. Although the maximum angular velocity of the inversion was smaller and the duration of inversion phase of 'giving way' was shorter than in previous reports, the characteristics of the following eversion phase of 'giving way' were consistent with earlier reports. The eversion must be a more specific phase than the inversion in the kinematics of 'giving way'.

OBJECTIVE: To investigate the acute phase response to surgical stress in patients with rheumatoid arthritis (RA) treated with tofacitinib, a Janus kinase (JAK) inhibitor. METHODS: A retrospective matched pair analysis of 34 patients treated with tofacitinib and 34 patients treated with conventional disease-modifying anti-rheumatic drugs (csDMARDs) was performed. Patients were matched for age, sex, and type of surgery; body temperature, C-reactive protein (CRP) level, and white blood cell (WBC) count, neutrophil count, and lymphocyte count were compared between the tofacitinib and csDMARDs groups within 2 weeks after orthopedic surgery. Postoperative complications within 90 days were also assessed. RESULTS: No surgical site infection or delayed wound healing was observed in the tofacitinib group; whereas, one case of superficial infection was noted in the csDMARDs group. A similar postoperative increase in body temperature and CRP level was observed in both the groups. Postoperatively, the tofacitinib group showed an increase in WBC and neutrophils counts and a decrease in lymphocyte count, unlike the csDMARDs group. In contrast to two patients (2.6%) in the csDMARDs group, seven patients (20.6%) in the tofacitinib group had lymphocyte counts below 500 cells/μL within 2 weeks postoperatively. CONCLUSION: Tofacitinib did not suppress postoperative increase in body temperature and CRP level. Because of the postoperative decrease in lymphocyte count in patients treated with tofacitinib, the timing for resuming tofacitinib treatment after surgery should be carefully considered. Key Points • This study is the first to report the complications and systemic inflammatory responses after orthopedic surgery in patients treated with tofacitinib in comparison with matched pairs treated with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) • While tofacitinib does not suppress postoperative increase in body temperature and CRP level, the postoperative decrease in lymphocyte count in patients treated with tofacitinib is significant compared with patients treated with csDMARDs • Attention should be paid to a reduced lymphocyte count when to resume tofacitinib after surgery.

BACKGROUND: The effectiveness of scarf and Akin osteotomy with intra-articular lateral soft tissue release for the correction of hallux valgus (HV) in patients with rheumatoid arthritis (RA) has not been elucidated. METHODS: A total of 36 feet in 28 patients with RA who had scarf and Akin osteotomy with intra-articular stepwise lateral soft tissue release between 2015 and 2020 at a single institute were investigated retrospectively, with a mean follow-up period of 32.0 ± 16.9 months. Radiographic evaluations including the HV angle, intermetatarsal angle, and sesamoid position were performed preoperatively and postoperatively. Clinical outcomes were assessed using the Japanese Society of Surgery of the Foot (JSSF) hallux scale and self-administered foot evaluation questionnaire (SAFE-Q). RESULTS: The procedure resulted in significant HV correction, with a recurrence rate of 13.9%. The JSSF scale and all five SAFE-Q subscale scores significantly improved (p < 0.05), with no major complications. More than 90% of cases achieved adequate lateral soft tissue release without sacrificing the adductor tendon of the hallux. CONCLUSIONS: Intra-articular stepwise lateral soft tissue release in combination with scarf and Akin osteotomy provided satisfactory radiographic and patient-reported outcomes for the correction of HV in patients with RA with minimum lateral soft tissue release.

CASE: Gnathodiaphyseal dysplasia is a generalized skeletal syndrome characterized by frequent bone fractures in childhood, sclerosis and bowing of tubular bones, and cemento-osseous lesions of the jawbones. We present the case of a 53-year-old man with gnathodiaphyseal dysplasia who presented with pathological fracture of the tibial shaft. Internal fixation with the Ender nail was successfully performed with 2 years of follow-up. CONCLUSION: This is the first report describing the treatment of fracture in an adult patient with gnathodiaphyseal dysplasia. Internal fixation with the Ender nail was effective for the tubular bone with deformity. Callus formation was observed without delay.

Lubricin encoded by the proteoglycan 4 (Prg4) gene is produced from superficial zone (SFZ) cells of articular cartilage and synoviocytes, which is indispensable for lubrication of joint surfaces. Loss-of-function of human and mouse Prg4 results in early-onset arthropathy accompanied by lost SFZ cells and hyperplastic synovium. Here, we focused on increases in the thickness of articular cartilage in Prg4-knockout joints and analyzed the underlying mechanisms. In the late stage of articular cartilage development, the articular cartilage was thickened at 2 to 4 weeks and the SFZ disappeared at 8 weeks in Prg4-knockout mice. Similar changes were observed in cultured Prg4-knockout femoral heads. Cell tracking showed that Prg4-knockout SFZ cells at 1 week of age expanded to deep layers after 1 week. In in vitro experiments, overexpression of Prg4 lacking a mucin-like domain suppressed differentiation of ATDC5 cells markedly, whereas pellets of Prg4-knockout SFZ cells showed enhanced differentiation. RNA sequencing identified matrix metalloproteinase 9 (Mmp9) as the top upregulated gene by Prg4 knockout. Mmp9 expressed in the SFZ was further induced in Prg4-knockout mice. The increased expression of Mmp9 by Prg4 knockout was canceled by IκB kinase (IKK) inhibitor treatment. Phosphorylation of Smad2 was also enhanced in Prg4-knockout cell pellets, which was canceled by the IKK inhibitor. Expression of Mmp9 and phosphorylated Smad2 during articular cartilage development was enhanced in Prg4-knockout joints. Lubricin contributes to homeostasis of articular cartilage by suppressing differentiation of SFZ cells, and the nuclear factor-kappa B-Mmp9-TGF-β pathway is probably responsible for the downstream action of lubricin. © 2020 American Society for Bone and Mineral Research (ASBMR).

OBJECTIVES: Patients with rheumatoid arthritis (RA) are at increased risk of falling; therefore, fall prevision and prevention are critical. The present study aimed to evaluate the ability of physical performance assessments to discriminate between RA patients with and without a history of falling. METHODS: Fifty patients with RA were divided into two groups according to the presence or absence of a history of falls within the previous 1 year. Physical performance was assessed using the short physical performance battery (SPPB), which consists of the timed standing balance, gait speed, and chair stand tests. Standing balance was also assessed as postural sway using a force platform in several positions including standing with both feet together, semitandem, and tandem. Backgrounds, SPPB, and postural sway were compared between the two groups. RESULTS: Fourteen patients (28%) reported one or more falls within the previous year. There were no significant intergroup differences in baseline characteristics or SPPB score. The group with a history of falls had significantly longer measured time for the 5-repetition chair stand test and significantly longer postural sway in the semitandem position. The discriminate analysis revealed that 5-repetition chair stand test or its combination with postural sway in the semitandem position significantly discriminated between fallers and non-fallers. CONCLUSION: Numerical evaluation of the chair stand test and postural sway in the semitandem position seems more appropriate than SPPB for assessing the fall risk of patients with RA.

OBJECTIVES: The purpose of this study was to clarify the effect of disease activity on recurrent deformities after resection arthroplasty for forefoot deformities in patients with rheumatoid arthritis (RA). METHODS: This study included 83 feet in 58 patients with RA who underwent resection arthroplasty of all metatarsal heads, with a minimum follow-up of 2 years. The patients' demographic characteristics, preoperative radiographic findings, and RA disease activity evaluated using the 28-joint disease activity score based on the erythrocyte sedimentation rate (determined preoperatively and at the final follow-up) were compared between feet with and without postoperative recurrent deformities of the toes. Recurrent deformities were assessed separately for the hallux and lesser toes. RESULTS: Recurrence in the hallux and lesser toes occurred in 23 feet (27.7%) and 13 feet (15.7%), respectively. With respect to recurrent hallux deformity, only the preoperative severity of hallux deformity was associated with recurrence. On the other hand, postoperative deformity of the lesser toes was positively associated with disease activity alone and not with other preoperative factors. CONCLUSION: Postoperative control of RA disease activity was associated with recurrent deformity of the lesser toes but not that of the hallux after resection arthroplasty of all metatarsals for rheumatoid forefoot deformities.

INTRODUCTION: The objective of this study was to quantitatively evaluate the effects of daily teriparatide on rheumatoid arthritis patients using predicted bone strength (PBS) assessed by quantitative computed tomography-based finite-element analysis (QCT/FEA) and using bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA), and to prospectively investigate clinical determinants associated with PBS and BMD increases. MATERIALS AND METHODS: Participants comprised 39 patients (mean age, 69 years; disease activity score assessing 28 joints with CRP, 3.0; previous vertebral fractures, 82%) enrolled in this study. BMD by DXA and PBS by QCT/FEA of lumbar spine (LS) and proximal femur were measured at baseline, and after 6 and 12 months. In the groups showing increases in these values, variables that may have affected these increases were evaluated using univariate logistic regression analysis. RESULTS: Daily teriparatide treatment significantly increased not only LS BMD, but also LS PBS in RA patients with osteoporosis after both 6 and 12 months of treatment. Increases in N-terminal type I procollagen propeptide (PINP) at 1 and 3 months were significantly associated with increased LS PBS at 12 months according to univariate logistic regression analysis. The threshold value for increased PINP at 1 month for increased PBS at 12 months was 75 µg/L. CONCLUSIONS: Increased LS PBS at 12 months was predicted by increased PINP at 1 month from baseline.

Hypertrophic peroneal tubercle (HPT) is an overgrowth of the peroneal tubercle located on the lateral aspect of the hindfoot, which could cause tenosynovitis of the peroneus longus tendon. Os peroneum (OP) is an accessory ossicle that exists in the peroneus longus tendon at the lateral aspect of the calcaneocuboid joint. Both HPT and OP can cause lateral foot pain and occasionally require surgical treatment. We encountered a case of lateral foot pain of HPT coexisting with OP. Careful preoperative magnetic resonance imaging, dynamic ultrasonographic image, and block injection suggested an impingement of HPT and OP as a cause of lateral foot pain. Surgical resection of HPT, while retaining OP, successfully achieved pain relief in the patient. To the best of our knowledge, this is the first report presenting a case of HPT coexisting with OP successfully treated without OP resection.

Dysplasia epiphysealis hemimelica (DEH), also known as Trevor's disease, is a rare overgrowth of cartilage that commonly arises in the epiphyseal bone of children. We report a rare case of DEH originating from a talus accompanied by multiple intra-articular free bodies in a 7-year-old patient with ankle instability. After the primary surgery for free body removal and microfracture technique for the cartilage defects in the ankle joint, the free body recurred. Secondary surgery of arthroscopic free body removal with lateral ankle ligament repair succeeded in treating the patient, without further recurrence of the free body.

Medial bone excrescence at the base of the distal phalanx of the hallux is a common manifestation which is rarely painful. In this case report, we described the first case of the excrescence becoming symptomatic one year after a metatarsophalangeal (MTP) joint arthrodesis of the great toe in a 74-year-old female. The medial bony excrescence which was obscure preoperatively became obvious postoperatively in the anteroposterior foot radiographs. The patient was successfully treated by an excision of the excrescence. In order to clarify the pathology of the excrescence, we reviewed the radiographs with respect to the excrescence before and after hallux surgeries including 97 metatarsal osteotomies and 33 MTP joint arthrodesis. The width of the excrescence measured in the anteroposterior foot radiographs displayed substantial increment one month after the hallux surgeries (osteotomy group: 0.9 ± 0.7 vs. 1.5 ± 0.7 mm, p < 0.01; arthrodesis group: 1.3 ± 0.8 vs. 1.8 ± 1.0 mm, p < 0.01). However, there was no significant difference in the width of the excrescence between one month after surgery and at the most recent follow-up of around 20 months in average after the surgery (osteotomy group: 1.5 ± 0.7 vs. 1.4 ± 0.7 mm, p = 0.62; arthrodesis group: 1.8 ± 1.0 vs. 1.8 ± 0.7 mm, p = 0.37). The present case and our radiographic review suggested that the postoperative medial bony excrescence was not the result of change of position of the preexisting excrescence. The correction of pronation deformity through hallux surgeries could emphasize the medial bony excrescence and cause symptomatic irritation upon shoe contact.

INTRODUCTION: Clinical studies of intra-articular injection of mesenchymal stem cells for osteoarthritis (OA) indicate its efficacy. Here, we retrospectively investigated the associations of pretherapeutic magnetic resonance imaging (MRI) findings with the clinical outcomes up to 6 months, after intra-articular administration of adipose-derived stem cells (ASCs) to knee OA patients. METHODS: We first analyzed alterations of the visual analog scale (VAS) and knee injury and osteoarthritis outcome score (KOOS) in 57 knees of 34 patients from whom clinical scores were obtained before ASC therapy, and at 1, 3, and 6 months. Among the patients, we further examined MRI findings of 34 knees of 19 patients whose pretherapeutic MRI data were available. RESULTS: The mean improvement of VAS and KOOS-total during 6 months was 2.6 ± 4.0 (from 6.1 ± 2.5 to 3.5 ± 2.9, P < 0.001) and 10.2 ± 12.4 (from 54.4 ± 12.7 to 64.6 ± 13.8, P < 0.01), respectively. Scales related to pain and symptoms improved earlier than those related to activities of daily living (ADL) and sports/recreation. Improvement of VAS and KOOS-sports/recreation was significantly higher in patients with more severe cartilage lesions. Similarly, osteophyte lesions were associated significantly with improvement of VAS and KOOS-ADL, and BML was associated with KOOS-ADL and KOOS-sports/recreation. CONCLUSIONS: In intra-articular administration of autologous ASCs for knee OA, improvement of VAS and KOOS-sports/recreation was significantly higher in patients with more severe cartilage lesions. Similarly, osteophyte lesions were associated significantly with improvement of VAS and KOOS-ADL, and BML was associated with KOOS-ADL and KOOS-sports/recreation. Clinical studies with larger numbers of patients and various kinds of data are necessary to predict therapeutic effects.

Objectives: There have been few reports on factors affecting bone union after metatarsal osteotomies. The purpose of this study was to clarify the factors affecting bone union after distal shortening oblique osteotomy of the lesser metatarsals.Methods: Patients who underwent distal shortening oblique osteotomy of the lesser metatarsals were retrospectively investigated. Failure to achieve bone union at 6 months after surgery was defined as delayed union. Background characteristics and radiographic measurements were compared between patients with and those without delayed union, and factors affecting bone union were assessed using multivariate analysis.Results: Among 204 toes in 58 patients evaluated in this study, delayed union occurred in 28%. In multivariate analysis, corticosteroid use (odds ratio (OR), 3.68; 95% confidence interval (CI), 1.65-8.16; p< .01), larger preoperative overlap between the metatarsal and the proximal phalanx (OR, 1.11 (per 1 mm increase); 95% CI, 1.02-1.21; p= .02), and larger gap at the osteotomy site (OR, 3.02 (per 1 mm increase); 95% CI, 1.76-5.16; p< .01) were identified as independent risk factors of delayed union.Conclusion: The identified risk factors of delayed union after distal shortening metatarsal osteotomies were corticosteroid use, preoperative overlap between the metatarsal and the proximal phalanx, and a gap at the osteotomy site.

OBJECTIVE: To investigate whether abatacept (ABA) causes more adverse events (AE) than conventional synthetic disease-modifying antirheumatic drugs (csDMARD) after orthopedic surgery in patients with rheumatoid arthritis (RA). METHODS: A retrospective multicenter nested case-control study was performed in 18 institutions. Patients receiving ABA (ABA group) were matched individually with patients receiving csDMARD and/or steroids (control group). Postoperative AE included surgical site infection, delayed wound healing, deep vein thrombosis or pulmonary embolism, flare, and death. The incidence rates of the AE in both groups were compared with the Mantel-Haenszel test. Risk factors for AE were analyzed by logistic regression model. RESULTS: A total of 3358 cases were collected. After inclusion and exclusion, 2651 patients were selected for matching, and 194 patients in 97 pairs were chosen for subsequent comparative analyses between the ABA and control groups. No between-group differences were detected in the incidence rates of each AE or in the incidence rates of total AE (control vs ABA: 15.5% vs 20.7% in total, 5.2% vs 3.1% in death). CONCLUSION: Compared with csDMARD and/or steroids without ABA, adding ABA to the treatment does not appear to increase the incidence rates of postoperative AE in patients with RA undergoing orthopedic surgery. Large cohort studies should be performed to add evidence for the perioperative safety profile of ABA.

Objective: To evaluate the difference between adult juvenile idiopathic arthritis (JIA, starting at <16 years) and rheumatoid arthritis (RA).Methods: Data on 128 adult JIA patients were from the National Database of Rheumatic Diseases in Japan (NinJa), 2014, divided into 4 groups by period of disease onset (Group 1: 2000-2013, n = 32; Group 2: 1981-1999, n = 32; Group 3: 1966-1980, n = 31; Group 4: ∼1965, n = 33). Disease activity, treatment and long-term prognosis of adult JIA patients were compared with RA patients matched for sex- and disease duration in each era.Results: In Groups 1 and 2, adult JIA patients had significantly lower clinical disease activity indices (CDAI) (Group 1: adult JIA 1.5 [0.4-6.9]-vs-RA 5.3 [2.5-10.3], p = .001, Group 2: 2.6 [0.6-9.0]-vs-6.9 [3.5-11.0], p = .001, shown as median [quartile range], p-value, respectively), and had higher CDAI remission rates than RA patients (Group 1: 54.8%-vs-28.2%, p = .002, Group 2: 51.7%-vs-17.0%, p < .001). More adult JIA than RA patients in Group 1 used biologics (62.5%-vs-24.7%, p < .001). However, there were no adult JIA-vs-RA differences in joint destruction and physical function in any group.Conclusions: Adult rheumatologists must recognize that adult JIA patients are different from RA patients even when disease duration is the same.

Talonavicular joint arthritis is a great concern after ankle fusion. Although arthrodesis is the gold standard treatment for this complication, it could initiate a vicious cycle of further adjacent joint arthritis. An alternative that may delay or eliminate the need for arthrodesis is excision arthroplasty; however, there are only a few reports on its application on a talonavicular joint. We report 3 cases of excision arthroplasty with interpositional Achilles tendon autograft for the treatment of end-stage talonavicular osteoarthritis in low-demand elderly patients. In 1 patient, excision arthroplasty was performed after tibiotalocalcaneal arthrodesis, and in 2 patients, it was performed after tibiotalar arthrodesis, in which the subtalar joints were also damaged and fused simultaneously on performance of the interpositional arthroplasty of the talonavicular joint. In all cases, pain relief and functional activities of daily living improvement were achieved with this procedure. At a minimum follow-up of 1 year, no patient reported adjacent joint symptoms or flatfoot progression. These cases show that interpositional arthroplasty with Achilles tendon autograft is an effective treatment for end-stage talonavicular arthritis in patients with fused ankle and subtalar joints. This procedure was helpful in relieving pain and improving activities of daily living function in low-demand elderly patients with the preservation of movement of the talonavicular joint. Autograft was considered to be superior to other grafts with respect to availability, graft rejection, or allergy development. Fused subtalar joint resolved the concerning issues, such as flatfoot progression and muscular weakness of ankle plantar flexion, associated with this procedure.

Interphalangeal hyperextension is one of the major hallux deformities in patients with rheumatoid arthritis; however, there is yet no established surgical method for this deformity. We here present the case of a 69-year-old female patient with rheumatoid arthritis who developed hallux interphalangeal hyperextension and painful callosity on the plantar hallux accompanied by limited dorsiflexion at the metatarsophalangeal joint. Lateral weight-bearing radiograph of the foot revealed misalignment of the medial column and hallux, including a collapsed medial arch, elevated first metatarsal, plantar flexion and deviation of the proximal phalanx, and hyperextension of the distal phalanx. The foot was successfully treated and became symptom-free with opening wedge osteotomy of the medial cuneiform, plantar and proximal translation of the metatarsal head, and tenotomy of the extensor hallucis longus. This case suggests that reconstruction of the sagittal alignment of the medial column and hallux through a combination of osteotomy and soft tissue intervention could be an optional treatment for interphalangeal hyperextension.

CASE: Stiff-person syndrome is a rare neurological disorder characterized by rigidity and painful spasms of the trunk and limbs, and patients sometimes have difficulty in walking due to rigid toe deformities. This is a case report of a 76-year-old woman suffering from stiff-person syndrome with painful rigid toe deformities regained walking ability after metatarsal osteotomy and cutting of the toe extensors for all toes in the left foot. CONCLUSION: For patients with stiff-person syndrome, surgical intervention is a powerful treatment option when they have developed rigid and painful toe deformities despite adequate pharmacological treatment.

CTLA4-Ig (cytotoxic T-lymphocyte antigen 4-immunoglobulin; Abatacept) is a biologic drug for rheumatoid arthritis. CTLA4 binds to the CD80/86 complex of antigen-presenting cells and blocks the activation of T cells. Although previous reports showed that CTLA4-Ig directly inhibited osteoclast differentiation, the whole inhibitory mechanism of CTLA4-Ig for osteoclast differentiation is unclear. Bone marrow macrophages (BMMs) from WT mice were cultured with M-CSF and RANKL with or without the recombinant mouse chimera CTLA4-Ig. Intracellular calcium oscillations of BMMs with RANKL were detected by staining with calcium indicator fura-2 immediately after administration of CTLA4-Ig or after one day of treatment. Calcium oscillations were analyzed using Fc receptor gamma- (FcRγ-) deficient BMMs. CTLA4-Ig inhibited osteoclast differentiation and reduced the expression of the nuclear factor of activated T cells NFATc1 in BMMs in vitro. Calcium oscillations in BMMs were suppressed by CTLA4-Ig both immediately after administration and after one day of treatment. CTLA4-Ig did not affect osteoclastogenesis and did not cause remarkable changes in calcium oscillations in FcRγ-deficient BMMs. Finally, to analyze the effect of CTLA4-Ig in vivo, we used an LPS-induced osteolysis model. CTLA4-Ig suppressed LPS-induced bone resorption in WT mice, not in FcRγ-deficient mice. In conclusion, CTLA4-Ig inhibits intracellular calcium oscillations depending on FcRγ and downregulates NFATc1 expression in BMMs. © 2019 American Society for Bone and Mineral Research.

Total ankle arthroplasty is a useful surgical procedure for osteoarthritis of the ankle, but aseptic loosening of components is an issue. We report here a case of aseptic implant loosening with metallosis after total ankle arthroplasty using the TNK ankle (Kyocera, Kyoto, Japan), which occurred despite the components being ceramic. We also report favorable results from our method of treatment using a total talar prosthesis in the revision surgery. During the revision surgery, synovial metallosis was found, probably related to superficial damage to the screw affixing the tibial component to the bone. Because both the tibial and talar components were loose, all the components and the remaining talar bone were removed. A new tibial component and a custom-made alumina-ceramic total talar prosthesis was inserted. Pain relief was achieved and maintained through the latest follow-up visit at 42 months after revision surgery. Dorsiflexion of the ankle improved from 0° to 5° and plantarflexion remained unchanged from its preoperative range of 20°. The American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 38 to 80 points. To the best of our knowledge, this is the first reported case of an alumina-ceramic total ankle prosthesis loosening caused by metallosis resulting from screw abrasion. Favorable treatment results were obtained by using a total talar prosthesis in the revision surgery.

Receptor activator of nuclear factor κB ligand (RANKL) induces osteoclast (OC) differentiation from bone marrow-derived macrophages (BMMs). The transcription factors nuclear factor of activated T cells 1 (NFATc1) and interferon regulatory factor (IRF) 8 play positive and negative roles, respectively, in this process. However, genomewide mapping of the active cis-regulatory elements regulating OC differentiation has not been performed, and little is known about the global landscape of OC-specific gene regulation. We used chromatin immunoprecipitation and formaldehyde-assisted isolation of regulatory elements followed by sequencing to show that PU.1 transcription factor binding motifs were overrepresented at active cis-regulatory regions in both murine BMMs and OCs, while IRF and NFAT binding motifs were selectively enriched at these regions in BMMs and OCs, respectively. We also found that RANKL induced the downregulation of Irf8 and upregulation of Nfatc1 expression, which was associated with dramatic alterations in histone modification. BMM-specific PU.1 binding sites were observed to overlap with IRF8 binding sites in BMMs, and this also occurred for OC-specific PU.1 binding sites and NFATc1 binding sites in OCs. The expression of genes with IRF8 peaks within BMM-specific PU.1 binding sites was significantly higher in BMMs than in OCs, while that of genes with NFATc1 peaks within OC-specific PU.1 binding sites was significantly higher in OCs than in BMMs. Our results suggest that PU.1 switches its transcription partner from IRF8 to NFATc1 and alters the binding regions during RANKL-induced osteoclastogenesis, which is associated with changes in epigenetic profiles and the control of cell type-specific gene expression. © 2019 American Society for Bone and Mineral Research.

Intercuneiform arthrodesis is often required for various midfoot pathologies; however, intercuneiform screw insertion is not easy due to the complicated anatomical structure of cuneiforms. This study aimed to determine the advisable screw entry point and direction using intraoperatively detectable landmarks. The computed tomography (CT) scan data of feet were reformatted using OsiriX software multiplanar reconstruction. First, based on the data of 10 CT scans of normal feet, we determined the advisable screw entry point at the upper one-third in the dorsoplantar direction and center in the anteroposterior direction on the medial aspect of the medial cuneiform and insertion direction toward the outermost point of the base of the fifth metatarsal in the axial plane and parallel to the plantar surface in the coronal plane. Second, we examined the accuracy of these newly designed guideposts in the simulation using other CT scan data of the other 27 normal feet and 12 flat feet. The simulated screw trajectory penetrated the mid three-fifths of all three cuneiforms in 97% of the normal feet and 92% of the flat feet with no cases of cortical wall violation. Levels of Evidence: Level V: Expert opinion.

OBJECTIVES: To investigate the distribution of 25-question Geriatric Locomotive Function Scale (GLFS-25) scores in Japanese rheumatoid arthritis (RA) patients and evaluate relationships with clinical variables. METHODS: Among 15,115 patients registered in the NinJa database for fiscal year 2015, 1710 with complete GLFS-25 and disease activity score-28 (DAS28) data were analyzed. Correlations between GLFS-25 score and clinical variables were assessed by Spearman coefficients. Mean GLFS-25 scores were compared among DAS28 groups (<2.6, 2.6-3.1, 3.2-5.0, ≥5.1) using the Kruskal-Wallis test. To evaluate the performance of the GLFS-25 and Health Assessment Questionnaire Disability Index (HAQ-DI) for predicting DAS28 ≥ 3.2 (moderate/high disease activity), receiver operator characteristic (ROC) curves were constructed. RESULTS: GLFS-25 score was significantly correlated with age, disease duration, DAS28, and HAQ-DI. GLFS-25 score increased in parallel with DAS28. The proportion of patients with locomotive syndrome stage 2 also increased with DAS28. Area under the curve values for HAQ-DI and GLFS-25 score were 0.739 and 0.768, respectively. At a GLFS-25 positive cutoff score ≥16, sensitivity was 0.716 and specificity was 0.661 for predicting DAS28 ≥ 3.2. CONCLUSION: This study documents the GLFS-25 score distribution in Japanese RA patients and demonstrates that GLFS-25 is a useful measure for evaluating functional ability in RA.