Is the increase in the number of total hip arthroplasties in Japan due to an aging society?

BACKGROUND: The number of total hip arthroplasty (THA) is increasing globally, including Japan. The Japanese Orthopaedic Association has been conducting a registry of joint replacement surgery, but there may be a gap between the reported numbers of THA in the registry and the actual number. This study aimed to investigate the exact number of THA and assess the trends in Japan using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB). METHODS: We downloaded data from 2014 to 2019 from the NDB Open Data. Data on primary THA were extracted, and we calculated the annual number and number for each 10-year age group and sex. We also compared the number and trends between elderly and non-elderly groups. RESULTS: During the study period, number of THAs increased by approximately 20,000, showing a continuous upward trend. The highest number of THAs were performed on patients in their 60s, except for the years 2014 and 2019. Comparison of the numbers in 2014 and 2019 by age group showed an increase in the number in patients in their 90s (by 2.05 times). There were significantly a greater number of elderly patients (P < 0.001). The number of THAs performed was higher in women than in men (P < 0.001). CONCLUSION: The number of THAs in Japan increased substantially from 2014 to 2019, despite a decrease in population. Significantly higher number of THAs were performed on elderly patients in Japan, which might be due to an aging society. The NDB data is highly valuable for epidemiological research in Japan, as it might enable the early detection of issues occurring during THA, facilitating their prompt integration into daily clinical practice.

Influence of broach surface design of a fully hydroxyapatite coated, double tapered stem on periprosthetic bone mineral density after total hip arthroplasty: a study based on the morphology of the proximal femur.

INTRODUCTION: This study aimed to compare the impact of different broach surface designs on post-operative clinical outcomes, bone reactions and changes in bone mineral density (BMD) in patients who underwent total hip arthroplasty (THA) using a fully hydroxyapatite coated and double tapered stem with either compaction shape (COM) or hybrid shape (HYB) broaches. MATERIALS AND METHODS: A retrospective analysis was conducted on 76 patients (100 hips) who underwent primary THA using the Avenir complete stem®. Patients were divided into two groups: the COM broach group (50 hips) and HYB broach group (50 hips). We evaluated clinical outcomes using the Japanese Orthopaedic Association hip scores one month before the surgery, and 12 and 24 months after the surgery. Radiographic findings, including stem alignment angles, radiolucent lines, spot welds, and cortical hypertrophy, were assessed. BMD around the stem in Gruen zones 1-7 was evaluated using dual-energy X-ray absorptiometry (DEXA) at 7 days, 12, and 24 months post-operatively. The Dorr classification was used to assess femoral morphology. RESULTS: There were no significant differences in clinical outcomes, radiographic findings, or BMD changes between the COM and HYB broach groups in the overall patient cohort. However, in Dorr type A femurs, the COM broach group demonstrated superior BMD superior preservation in zones 1 and 7 after 12 months and in zones 1, 6 and 7 after 24 months. Additionally, in Dorr type B femurs, significant BMD preservation was observed in zone 3 at 24 months in the COM broach group. CONCLUSIONS: This study suggests that the broach surface design of fully hydroxyapatite coated stems may influence periprosthetic BMD changes, especially in Dorr type A and B femurs. Surgeons should consider broach selection based on patient-specific femoral morphology to optimize BMD preservation in THA procedures using fully hydroxyapatite coated stems.

Effects of perioperative exercise therapy combined with nutritional supplementation on functional recovery after fast-track total hip arthroplasty.

BACKGROUND: The combination of exercise therapy combined with nutritional supplementation (Nutr) is widely used for frail or sarcopenic older persons. However, the effects of Nutr in elderly patients after fast-track total hip arthroplasty (THA) are unknown. This study examined the effects of perioperative Nutr on muscle strength, functional performance, and quality of life (QOL) in frail elderly women after fast-track THA. METHODS: A total of 58 frail elderly women aged 65-80 years scheduled for unilateral primary THA were randomly allocated to two groups: the physical exercise (Ex) combined with Nutr (Ex + Nutr; n = 29) group, and the Ex alone (Ex; n = 29) group. Protein and vitamin D supplements were provided daily from 4 weeks preoperatively to 8 weeks postoperatively (12 weeks) to the patients in the Ex + Nutr group, whereas the Ex group did not receive any supplements. Surgery and postoperative rehabilitation programmes during intervention were identical in both groups. Hip abductor and knee extensor muscle strength, functional performance (Timed Up & Go test, Harris Hip Score), and QOL (Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire) were assessed at baseline and at 12 weeks (8 weeks postoperatively). RESULTS: After the intervention, hip abductor muscle strength on the contralateral leg and knee extensor muscle strength on both sides significantly improved in the Ex + Nutr group compared to the Ex group (p = 0.03, 0.01, and 0.01, respectively). However, hip abductor muscle strength on the operated side did not differ significantly between the groups (p = 0.23). There were no significant differences in functional performance and QOL. CONCLUSION: Ex + Nutr does not have an additional effect on the improvement of hip abductor strength, functional performance, and QOL compared to Ex alone after fast-track THA. However, significant improvements were observed in the strength of some muscles after fast-track THA. TRIAL REGISTRATION: UMIN 000042964. THE IRB APPROVAL: This study was approved by the Mirai Iryo Reesearch Center (approval number TGE1602-115).

Increase in TPSB2 and TPSD1 Expression in Synovium of Hip Osteoarthritis Patients Who Are Overweight.

While research suggests that increasing body mass index (BMI) is a risk factor for hip osteoarthritis (HOA), the mechanisms of this effect are not fully understood. Tryptases are among the main proteases found in mast cells (MCs) and contribute to OA pathology. TPSB2, which encodes ß-tryptase, is increased in the synovium of overweight and obese knee OA patients. However, it remains unclear whether tryptase in the synovium of HOA is increased with increasing BMI. Here, we investigated tryptase genes (TPSB2 and TPSD1) in the synovium of overweight HOA patients. Forty-six patients radiographically diagnosed with HOA were allocated to two groups based on BMI, namely normal (<25 kg/m2) and overweight (25-29.99 kg/m2). TPSB2 and TPSD1 expression in the synovium of the two groups was compared using real-time polymerase chain reaction. To compare TPSB2 and TPSD1 expression in MCs between the groups, we isolated the MC-rich fraction (MC-RF) and MC-poor fraction (MC-PF), extracted using magnetic isolation. TPSB2 and TPSD1 expression was increased in the overweight group compared with the normal group. Expression of both genes in the MC-RF was significantly higher than that in MC-PF in both groups. However, TPSB2 and TPSD1 expression levels in the MC-RF did not differ between the groups. Tryptase genes were highly expressed in the synovium of overweight HOA patients. Further investigation to reveal the role of tryptase in the relationship between increasing BMI and HOA pathology is required.

Sports activity participation and subjective health status of patients after total hip arthroplasty via the anterolateral-supine approach: a case series study.

BACKGROUND: No reports have been published about participation in sports activity and subjective health status after total hip arthroplasty via the anterolateral approach in the supine position (ALS-THA) in Japanese patients. This study assessed sports activity participation and subjective health status, as well as factors potential associated with these variables, in patients who underwent ALS-THA. METHODS: Of 698 patients who underwent total hip arthroplasty at our institution between 2013 and 2018, questionnaires were sent to 355 patients under 80 years old who had undergone ALS-THA and 242 responded. Patients were asked about their subjective health status, participation in sports activity, the EuroQol 5-dimensions 5-level (EQ-5D-5L), the University of California Los Angeles (UCLA) activity scale score and the Forgotten Joint Score (FJS). Patient characteristics and hospitalization information were also collected. Patients' subjective health status was categorized as "healthy" or "unhealthy". Univariate and multivariate logistic regression analyses were performed to determine factors associated with participation in sports activity after ALS-THA and a "healthy" status. RESULTS: The pre- and postoperative sports activity participation rates were 54.0% and 57.8%, respectively. Most patients (76.8%, n = 182) were considered "healthy". Age (P = .019) and UCLA activity score (P < .001) were significantly associated with sports activity after ALS-THA. FJS (P = .002) and EQ-5D-5L (P = .004) were significantly associated with a "healthy" status. CONCLUSION: Patients participating in sports activity after ALS-THA are older and have higher UCLA activity scores and patients considered "healthy" have higher FJS and EQ-5D-5L scores.

Prevalence of locomotive syndrome in Japanese patients more than 10 years after total hip arthroplasty: A cross-sectional cohort study.

BACKGROUND: Locomotive syndrome (LS) is a high risk condition that requires nursing care. It is important to investigate the prevalence of and factors related to LS to maintain a healthy life expectancy for patients; however, only a few reports have focused on the relationship between LS and total hip arthroplasty (THA). The purpose of this study was to evaluate the prevalence of LS and to identify factors associated with LS in patients more than 10 years after THA. METHODS: This is a cross-sectional cohort study. Patients were assessed via a mail survey that included items regarding demographic data, cardiometabolic and motor disorders, the incidence of falls, physical activity level, and the 25-question Geriatric Locomotive Function Scale (GLFS-25) questionnaire. LS was defined as having a score ≥16 on the GLFS-25, and the respondents were categorized into two groups: an LS group and a non-LS group. The prevalence of LS was calculated in each gender and age group. Differences in variables between the groups were determined using the unpaired t-test and chi-squared test. RESULTS: A total of 593 patients were included in the study (mean age, 70.4 years; 525/593 females). According to the GLFS-25, 164 patients (27.7%; 21.1% men and 28.8% women) were classified as having LS, which increased with age. In addition, compared with the non-LS group, the LS group had a significantly higher prevalence of motor diseases, cardiometabolic diseases, and falls and significantly lower levels of activity. CONCLUSION: These findings suggest that the prevalence of LS in patients more than 10 years after THA is 27.7%. The result suggest that the prevalence of LS in patients more than 10 years after THA is similar to the prevalence of LS in the general elderly population. Furthermore, LS is related to not only motor diseases but also cardiometabolic diseases.

Increased Synovial CD14 mRNA Expression and Proportion of CD14high Subsets in Early-Stage Hip Osteoarthritis: Propensity Matched Score Analysis.

The pathophysiology of early-stage hip osteoarthritis (EOA) is not fully understood. Although a previous study in an age-unmatched cohort reported that the number of macrophages was increased in knee EOA compared to late OA (LOA), it remained unclear whether increased macrophages in EOA accurately reflect EOA pathology. We investigated the differences in CD14 expression levels between EOA and LOA using age-unmatched and -matched cohorts. Synovial tissues were obtained from 34 EOA (Tönnis grades 0 and 1) and 80 LOA (Tönnis grades 2 and 3) patients. To correct for differences in demographics between patients with LOA and EOA, we also created propensity score-matched cohorts (16 EOA and 16 LOA). CD14 expression and its association with pain was estimated in LOA and EOA before and after propensity matching. We performed flow cytometry on tissues from the 16 patients, with 8 from each group, to assess for CD14+ subsets in the cells. The CD14 expression in EOA was higher than that in LOA both before and after propensity matching. The proportion of CD14high subsets in EOA was higher than that in LOA. The CD14 expression was associated with pain in EOA before matching. However, no difference was observed between the pain and CD14 expression after matching in EOA. The increased CD14 expression and the proportion of CD14high subsets may be important features associated with hip EOA pathology. To accurately compare early and late OA, the analysis of a propensity score-matched cohort is necessary.

A predictive model for hip abductor strength and knee extensor strength 12 months after total hip arthroplasty with an interaction term.

BACKGROUND: Identifying populations with poor muscle recovery after total hip arthroplasty (THA) is important for postoperative physical therapy. Preoperative muscle strength is a strong factor that determines postoperative muscle strength. However, this effect may depend on other factors. Thus, predictive models with interaction terms are important for accurately predicting postoperative muscle strength. This study aimed to develop a predictive model for lower muscle strength 12 months after THA which incorporates interaction terms. METHODS: Subjects were female patients with hip osteoarthritis who underwent unilateral THA. Patients with locomotor disorders, neurological disorders, or postoperative complications were excluded. Hip abductor and knee extensor strength were measured, and a generalized linear model approach with preoperative muscle strength, age, body weight, height, disease duration, physical activity, and leg extension as explanatory variables was used to identify factors that determine muscle strength 12 months after THA. Models with interaction terms between preoperative muscle strength and other explanatory variables were also examined. RESULTS: A total of 82 patients were analyzed. Preoperative muscle strength, age, body weight, physical activity, and disease duration were extracted as factors that significantly and independently determine hip abductor and knee extensor strength. The interaction term between preoperative muscle strength and age was identified as a factor that significantly determines knee extensor strength. Regression coefficients for preoperative knee extensor strength and postoperative muscle strength were significant when age was +1 SD, but not when age was -1 SD. CONCLUSIONS: The predictive model demonstrated that lower muscle strength 12 months after THA is determined by preoperative muscle strength, age, weight, physical activity, disease duration, and preoperative muscle strength, with the effect of preoperative muscle strength on knee extensor strength being dependent on age. When predicting postoperative knee extensor strength using preoperative muscle strength, it is important to consider the effect of age.

Elevated levels of TNF-α, IL-1ß and IL-6 in the synovial tissue of patients with labral tear: a comparative study with hip osteoarthritis.

BACKGROUND: Labral tear can be the initiating factor in the onset of hip osteoarthritis (HOA). However, the physiopathology of labral tear is not fully understood. Our aim was to compare synovial tissue inflammatory cytokine levels between patients with labral tear and late-stage HOA. METHODS: Synovial tissue from sites showing the greatest inflammation was harvested from 106 hips from 100 subjects during hip surgery. RNA was extracted, and levels of TNFA, IL1B, IL6 and COX2 mRNA were compared among all patients using real-time PCR. Additionally, we examined whether femoroacetabular impingement (FAI) was associated with elevated levels of inflammatory cytokines in patients with labral tear. To analyze the effects of TNF-α on inflammatory mediators in hip synovial tissue, synovial fibroblasts were extracted from hip synovial tissue of patients with labral tear and late-stage HOA (n = 5 each). Mononuclear cells were extracted from synovial tissue, cultured for 7 days, and stimulated with control or 10 ng/mL human recombinant TNF-α for 1 day. mRNA was extracted from stimulated cells and IL1B, IL6, and COX2 levels were determined using real-time PCR. RESULTS: TNFA, IL1B, and COX2 expression in synovial tissue were significantly higher in patients with labral tear than late-stage HOA (TNFA, p <  0.001; IL1B, p <  0.001; COX2, p = 0.001). There were no differences in expression between patients with labral tear with and without FAI (TNFA, p = 0.546; IL1B, p = 0.559; IL6, p = 0.599; COX2, p = 0.124). Compared to vehicle control, TNF-α stimulation significantly elevated IL1B, IL6, and COX2 expression in synovial fibroblasts collected from patients with labral tear and late-stage HOA (IL1B, p = 0.043 and p = 0.043; IL6, p = 0.043 and 0.043; COX2, p = 0.043 and p = 0.080, respectively). CONCLUSIONS: TNFA, IL1B, and COX2 expression were elevated in the synovial tissue of patients with labral tear. Further investigations are needed to reveal the relationship between inflammatory cytokine levels and various aspects of labral tear pathology, including pain and the onset and progression of OA.

Efficacy and safety of arthroscopic treatment for native acute septic arthritis of the hip joint in adult patients.

BACKGROUND: As septic arthritis is time-dependent and has a propensity for irreversible joint damage, early diagnosis and treatment are needed. Frequently, adult patients with septic arthritis cannot undergo invasive surgery because of comorbidities and a weakened immune system. Hip arthroscopic irrigation and debridement for native acute septic arthritis of the hip joint have been performed as the first choice of treatment for patients of all ages. This study aimed to assess the efficacy and safety of arthroscopic management for native acute septic arthritis of the hip joint in adult patients. METHODS: Five adult patients (mean age, 46.2 years; all male) were retrospectively reviewed. Immediately after diagnosis, all patients underwent hip arthroscopic irrigation, debridement with synovectomy, and drainage. Partial weight-bearing was permitted once the C-reactive protein level normalised to < 1.0 mg/dl. Preoperative comorbidities, bacterial culture results, surgical complications, duration of hospital stay, time-to-confirmed normalisation of the C-reactive protein level, and recurrence incidence were evaluated. RESULTS: All patients had comorbidities, and the cultured microorganisms differed among cases. There were no complications related to arthroscopic surgery. All patients achieved confirmed C-reactive protein normalisation within an average of 69.8 days, and there was no recurrence during the follow-up period (mean, 40.2 months; range, 16-60 months). CONCLUSION: Arthroscopic management for native acute septic arthritis of the hip joint is a safe and effective procedure in adult patients.

Management of regional bone bank during declaration of a state of emergency concerning the COVID-19 in Japan.

Bone banks are necessary for providing biological allografts for a series of orthopedic procedures. As nations cope with new realities driven by the 2019 coronavirus disease (COVID-19) pandemic, health-care providers, institutions, and patients share a particular concern about the effect of COVID-19 on organ donation and transplantation. Here, we describe the management of the Kitasato University Bone Bank during the state of emergency declared in response to COVID-19. Living donors received pre-operative screening by PCR, and allograft bone from COVID-19-negative donors was cryopreserved as transplantable tissues. The weekly rate of infection gradually increased from February 2-9 to April 5-11 in the dead donor-derived allograft bone-harvesting region covered by the Bank. It is becoming clear that the virus can be transmitted by asymptomatic patients, and that this route may have facilitated the spread of COVID-19. Therefore, the Bank stopped dead donor donation to consider the safety of medical staff. Three recipients received bone allografts following pre-operative COVID-19 screening by PCR. All patients were asymptomatic after bone allograft. Our experience may provide helpful information for the management of tissue banks.

Central sensitization inventory scores correlate with pain at rest in patients with hip osteoarthritis: a retrospective study.

BACKGROUND: Patients with persistent pain due to osteoarthritis (OA) complain of multiple symptoms that cannot be explained solely by structural changes. A poor correlation exists between structural and inflammatory changes in OA and pain levels. Central sensitization (CS) has been identified as a factor that induces chronic pain in patients with OA. Although it is important to identify osteoarthritis patients with CS components, the prevalence and characteristics of CS, especially those in patients with hip OA, are not well understood. Thus, we aimed to determine the prevalence and characteristics of CS in patients with hip OA, in this study. METHODS: The CS Inventory (CSI), used as a non-invasive routine clinical tool to evaluate the presence of CS 1 month before surgery in 100 patients with hip OA, was measured at our outpatient clinic, and the data were retrospectively reviewed. We determined the number of patients with a CSI score of 40 points or higher and assessed the relationships between the CSI score and clinical factors (including age, duration of hip pain, degree pain at rest and on activity, by using the visual analogue scale [VAS] and the Harris Hip Score) using the Spearman's correlation coefficient. RESULTS: The mean age of participants was 63.9 ± 11.6 years, and there were 15 men and 85 women. All patients had hip OA, categorised as advanced and terminal stage (Tönnis grade 2-3) on preoperative plain radiography. The mean duration of hip pain was 4.2 ± 4.4 years. The mean CSI score was 19.5 ± 11.3 and 5 (5.0%) of the patients had a score of 40 or more points. CSI scores correlated significantly only with VAS pain at rest (r = 0.348, P < 0.001). CONCLUSION: In this study, 1 out of every 20 hip OA patients had CS components. CSI scores were significantly correlated with pain at rest in hip OApatients. CS approaches to hip OA may be one of the treatment options for pain at rest.

The maximal gait speed is a simple and useful prognostic indicator for functional recovery after total hip arthroplasty.

PURPOSE: The present study aimed to compare the capabilities of preoperative usual and maximal gait speeds in predicting functional recovery in patients who have undergone total hip arthroplasty (THA). METHODS: Primary and unilateral THAs were performed in 317 patients, and the proportion of patients who achieved unassisted walking (functional recovery) 5 days postoperatively was recorded as an outcome measure. Preoperative functional assessment included hip pain, leg muscle strength, range of motion (ROM), and gait speed evaluations. The capabilities of preoperative usual and maximal gait speeds in predicting functional recovery were compared based on the areas under the curves (AUCs) of receiver operating characteristic (ROC) curves. Further, ROC curves were constructed using two models: 1. a model of gait speed only and 2. a clinical model including age, sex, leg muscle strength, and ROM. RESULTS: On the AUCs for predictive ability of functional recovery, maximal gait speed was greater than usual gait speed (0.66 and 0.70, respectively). The AUC for maximal gait speed was as large as that of the clinical model (0.70 and 0.70, respectively). CONCLUSION: Our results suggest that maximal gait speed is a simple and useful prognostic indicator of functional recovery in patients who have undergone THA.

Sports activity participation after curved periacetabular osteotomy for acetabular dysplasia.

BACKGROUND: Curved periacetabular osteotomy (CPO) was developed to treat acetabular dysplasia. Given that CPO can improve physical function in the early post-operative period, patients might be able to participate in sports activities post-operatively. Therefore, this study examined the post-operative sports activity participation and characteristics of acetabular dysplasia patients who have undergone CPO. METHODS: A total of 52 patients who underwent CPO for acetabular dysplasia were given a questionnaire on pre- and post-operative sports activities; 43 patients responded. We surveyed patients' sports activities, satisfaction, and physical function. Patients were divided according to whether they participated in sports activities after CPO. Physical function was compared before and after CPO. RESULTS: The pre- and post-operative sports activity participation rates were 55.8 and 72.1%, respectively. Patients mostly performed low-impact sports activities. Moreover, patients who participated in sports activities post-operatively had smaller pre-operative range of motion of hip flexion and returned to full weight bearing earlier. CONCLUSIONS: Among acetabular dysplasia patients who underwent CPO, 72.1% participated in sports activities post-operatively. Post-operatively, patients participated not only in low-impact sports activities, but also in high-impact ones. These findings might be useful for advising patients who are concerned about participating in sports activities after CPO.

Reference values for the locomotive syndrome risk test quantifying mobility of 8681 adults aged 20-89 years: A cross-sectional nationwide study in Japan.

BACKGROUND: The locomotive syndrome risk test was developed to quantify the decrease in mobility among adults, which could eventually lead to disability. The purpose of this study was to establish reference values for the locomotive syndrome risk test for adults and investigate the influence of age and sex. METHODS: We analyzed 8681 independent community dwellers (3607 men, 5074 women). Data pertaining to locomotive syndrome risk test (the two-step test, the stand-up test, and the 25-question geriatric locomotive function scale [GLFS-25]) scores were collected from seven administrative areas of Japan. RESULTS: The reference values of the three test scores were generated and all three test scores gradually decreased among young-to-middle-aged individuals and rapidly decreased in individuals aged over 60 years. The stand-up test score began decreasing significantly from the age of 30 years. The trajectories of decrease in the two-step test score with age was slightly different between men and women especially among the middle-aged individuals. The two physical test scores were more sensitive to aging than the self-reported test score. CONCLUSION: The reference values generated in this study could be employed to determine whether an individual has mobility comparable to independent community dwellers of the same age and sex.

Effects of Tissue Flossing and Dynamic Stretching on Hamstring Muscles Function.

Tissue flossing aims to improve range of motion (ROM), reduce pain, and enhance injury prevention. However, evidence is lacking regarding its effects. Therefore, this study examined the effects of flossing on hamstring muscles function in comparison to dynamic stretching (DS). Seventeen healthy young men ([mean ± SD] age, 23.2 ± 1.1 years; height, 1.72 ± 0.08 m; body mass, 63.5 ± 9.3 kg) volunteered as subjects in this randomized crossover trial. The subjects received flossing, DS, and control interventions in random order at least 1 week apart to eliminate the influence of the previous intervention. Flossing involved passive twisting and active movement using a floss band (Sanctband COMPRE Floss Blueberry, Sanct Japan Co., Ltd.). DS was performed for 4 minutes in 30-second sets consisting of 15 repetitions of 2 seconds stretching. The following were measured before and after each intervention: straight leg raise (SLR) test, passive knee extension (KE) test, passive torque, passive stiffness, fascicle length in the biceps femoris long head as an indication of hamstring muscles flexibility, and maximal isometric knee flexion contraction, maximal eccentric knee extension/flexion contraction, rate of force development, and muscle activity. Flossing yielded significant improvements in the SLR test (mean difference in post-intervention changes between interventions: 5.4°, percentage change from pre- to post-value: 13.4%, p = 0.004), passive KE test (6.2°, 4.5%, p < 0.001), passive torque at end-ROM (3.8 Nm, 4.7%, p = 0.03), and maximal eccentric knee flexion contraction (14.9% body weight, 8.2%, p = 0.03) than control. Moreover, flossing yielded 2.1-fold greater improvements in the passive KE test (3.8°, 4.5%, p = 0.03) and yielded significant improvements in the maximal eccentric knee extension contraction (29.9% body weight, 13.8%, p = 0.02) than DS. Therefore, flossing on hamstring muscles is more beneficial than DS with respect to increasing ROM and muscle exertion.

Muscle strength is associated with bone health independently of muscle mass in postmenopausal women: the Japanese population-based osteoporosis study.

There are conflicting reports on whether muscle strength is associated with bone mineral density (BMD) independently of muscle mass. Here, we examined the association between muscle strength and BMD in a representative population of Japanese women. Cross-sectional data from 680 postmenopausal women, who were participants in the 15th-year follow-up survey of the Japanese Population-based Osteoporosis cohort study, were analyzed. Areal BMD (aBMD) at the femoral neck and lumbar spine, whole-body bone mineral density, and appendicular skeletal muscle mass (ASM, kg) were measured by dual-energy X-ray absorptiometry. The ASM index (ASMI, kg/m2) was calculated as ASM divided by height squared (m2). Grip strength (kg) was measured as an indicator of muscle strength. Grip strength showed significantly (P < 0.05) positive relationships with aBMDs at several skeletal sites after adjusting for ASMI and age (standardized partial regression coefficient (ß) = 0.102 at femoral neck, ß = 0.126 at lumbar spine). Adjusted means of aBMD at the femoral neck and lumbar spine showed significant increasing trends from the lowest to highest tertile of grip strength. Our findings indicate that muscle strength is associated with aBMD at several sites independently of muscle mass in Japanese postmenopausal women. Thus, postmenopausal women with strong muscle strength tend to have a healthy bone status regardless of muscle size.

Electromyographic analysis of infraspinatus and scapular muscles during external shoulder rotation with different weight loads and positions.

BACKGROUND: Strengthening the infraspinatus is important in shoulder rehabilitation. Changes in infraspinatus activity with changing load and position have not been quantified. We sought to determine the most appropriate load and posture for early infraspinatus strengthening by assessing for changes in electromyographic activity in the healthy infraspinatus and other shoulder girdle muscles during isometric external rotational exercise under different loads with the shoulder adducted in the supine and seated positions. METHODS: Sixteen healthy adults (30 shoulders) performed isometric shoulder external rotation in the sitting and supine positions, starting with the shoulder and forearm in neutral position and the elbow flexed 90°. Loads (0.5 kg, 1 kg, and 2 kg) were applied at rest. We assessed the infraspinatus, upper trapezius, posterior deltoid, and biceps brachii. For analysis, we used the mean percentage of maximum voluntary muscle contraction (%MVC) value measured during each isometric contraction divided by the maximum voluntary muscle contraction (MVC) of each muscle. RESULTS: In the infraspinatus and posterior deltoid, significant interaction was observed between body position and load. Compared to the sitting position, an increase in activity in the supine position was attenuated as load increased, especially at 2 kg. The supine values of the upper trapezius and biceps brachii were always significantly lower than those in the sitting position regardless of load. CONCLUSION: The activity of the infraspinatus can be increased gradually during rehabilitation by beginning in the supine position, which assures low activity of the upper trapezius and biceps brachii. Exercise with the shoulder adducted in the supine position can strengthen the infraspinatus gradually and avoid compensatory mobility. LEVEL OF EVIDENCE: Level 3.

The impact of switching once-weekly teriparatide to denosumab in osteoporosis patients.

BACKGROUND: It has been reported that switching from daily (d) teriparatide (TPTD) to denosumab (DMAb) is effective for severe osteoporosis patients. However, there have been no reports about switching from weekly (w) TPTD to DMAb in patients with osteoporosis. Once-weekly 56.5-µg TPTD treatment increases bone mineral density (BMD) and reduces fracture events. The objective of the current retrospective study was to elucidate the impact of switching w-TPTD to DMAb in patients with osteoporosis. METHODS: In this study, 40 patients were treated with w-TPTD for 18 months and then switched to DMAb for 18 months. The sample included 2 men and 38 women with a mean age of 74.5 (60-85) years. Twenty-five subjects had primary osteoporosis, and 15 had secondary osteoporosis. The mean number of osteoporotic vertebral fractures was 4.1. Serum bone turnover markers and BMD were evaluated every 6 months. RESULTS: Bone alkaline phosphatase (BAP) and tartrate resistant acid phosphatase 5b (TRACP5b), markers of bone formation and resorption respectively, were not significantly different in w-TPTD subjects at 18 months compared with those at baseline (p > 0.05), but BAP and TRACP5b in subjects treated with DMAb were significantly lower at 36 months compared with those at baseline (p < 0.05). BMD of the lumbar spine (LS), femoral neck (FN), and total hip (TH) increased by 12.3%, 2.5%, and 2.2% by 36 months with DMAb treatment, significantly higher than at baseline (p < 0.05). Changes in BMD of FN and TH in primary osteoporosis patients were significantly higher than in secondary osteoporosis patients at 18 months (w-TPTD) and 36 months (DMAb, p < 0.05). CONCLUSION: BMD significantly increased in osteoporosis patients switched from w-TPTD to DMAb. However, the impact of switching from w-TPTD to DMAb in secondary osteoporosis patients was not as great as in primary osteoporosis patients at the view points of changes in BMD of FN and TH.

Relationship between spinal sagittal alignment and acetabular coverage: a patient-matched control study.

INTRODUCTION: The significance of the relationship between the spine and hip joints has been frequently discussed. However, the relationship between acetabular coverage and spinal sagittal alignment has not been fully elucidated as previous studies did not adequately control for factors that might affect the spinopelvic alignment. The aim of this study was to elucidate the impact of acetabular coverage on spinal sagittal alignment by comparing patient groups matched on sex, age, and the presence of hip and anterior impingement pain. MATERIALS AND METHODS: We prospectively enrolled 30 women undergoing periacetabular osteotomy (PAO) for developmental dysplasia of the hip (DDH) and 30 women undergoing hip arthroscopic surgery (HAS) for labral tears. The lateral centre edge angle was measured on hip radiographs. In addition, the sagittal vertical axis, pelvic tilt, pelvic incidence, sacral slope (SS), and lumbar lordosis (LL) were measured on preoperative plain radiographs of the whole spine to assess the sagittal spinal alignment. Clinical and radiologic data were compared between the two groups (PAO vs. HAS). RESULTS: The patient groups did not differ in age and body mass index. The mean SS was significantly greater in the PAO group (41.6° ± 1.6°) than in the HAS group (35.3° ± 1.5°; P = 0.0039). Additionally, the mean LL was significantly greater in the PAO group (54.5° ± 2.0°) than in the HAS group (45.1° ± 1.9°; P = 0.0015). CONCLUSIONS: The SS and LL were greater in patients with DDH than in patients with hip pain, but without DDH. Patients with DDH might show lumbar hyperlordosis to rotate the pelvis anteriorly, increasing the anterosuperior acetabular coverage.