Photoresponsive stripe pattern in achiral azobenzene liquid crystals.

A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid-crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33 . In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans-cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds.

Bone mineral density in patients with destructive arthrosis of the hip joint.

Recent reports have shown the existence of subchondral insufficiency fracture in rapidly destructive arthrosis of the hip joint (RDA), and the findings suggest that osteopenia is related to the pathogenesis of the rapid progression of this disease. Therefore, we measured bone mineral density (BMD) in RDA patients. We measured BMD of the lumbar spine, radius, and calcaneus using dual-energy X-ray absorptiometry in 19 patients with RDA and 75 with osteoarthritis of the hip (OA) and compared BMD at different skeletal sites between RDA and OA patients. No significant differences were observed in BMD of the lumbar spine, ultradistal radius, mid-radius, and calcaneous between the RDA and OA groups. Our data suggest that RDA is not accompanied by generalized osteoporosis. Factors other than generalized bone status, for example, BMD around the affected hip joint before destruction, need to be analyzed to elucidate the pathophysiological mechanism of RDA.

Relationship of acetabular dysplasia in females with osteoarthritis of the hip to the distance between both anterior superior iliac spines.

BACKGROUND: Acetabular dysplasia (AD) is the main cause of hip osteoarthritis in Japan. A simple method to evaluate acetabular dysplasia would be helpful for early treatment or prevention of hip osteoarthritis. Acetabular dysplasia is reported to be associated with pathological transverse growth of the pelvis, indicating that the distance between the 2 anterior superior iliac spines might be useful for screening and detection of acetabular dysplasia. The purpose of this study was to determine if the acetabular dysplasia radiographic parameters are related to the distance between the 2 anterior superior iliac spines in patients with hip osteoarthritis. MATERIAL AND METHODS: In this study, data obtained in a previous multi-institutional examination of patients with hip osteoarthritis in Japan were evaluated. The anterior superior iliac spine distances of 176 female patients (mean age, 54 years; range, 18-85 years) were measured by physical examination. The relationship between the anterior superior iliac spine distance and acetabular dysplasia was analyzed, and the anterior superior iliac spine distances of the patients with acetabular dysplasia who were at relatively high risk for hip osteoarthritis were compared with that of the patients at lower risk. RESULTS: A statistically significant relationship between the anterior superior iliac spine distance and all of the acetabular dysplasia parameters was observed. The anterior superior iliac spine distances of the acetabular dysplasia patients with a relatively high risk for radiographic acetabular dysplasia parameters were significantly smaller than those of patients at lower risk. Even after adjustment for age, height, and weight, significantly increased relative risk for having high risk AD was found in patients with an ASIS distance of less than 24.5 cm. CONCLUSIONS: There was a significant relationship between the anterior superior iliac spine distance and the degree of acetabular dysplasia.

Discrepancy in bone mineral densities at different skeletal sites in hip osteoarthritis patients.

OBJECTIVE: Increased femoral neck bone mineral density (BMD) in a hip with osteoarthritis (OA) has been previously reported, however, it is possible that increased BMD at sites other than the hip joint is influenced by the disease process of OA. Therefore, we measured BMD at locations different from the hip joint and determined whether higher BMD was also observed at these different skeletal sites in hip OA patients. METHODS: We measured BMD in 68 women (average age 61.0 years) scheduled to undergo total hip arthroplasty for end-stage OA and 100 healthy women (average age 60.9 years) as age-matched controls. BMD at the lumbar spine, radius, and calcaneus was measured by dual-energy X-ray absorptiometry (DXA). Moreover, we measured speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index of the calcaneus by quantitative ultrasonography (QUS). RESULTS: BMD obtained by DXA at the lumbar spine and radius was significantly higher in hip OA patients than in controls. However, at the calcaneus, no significant differences were observed between the groups in BMD obtained by DXA. SOS, BUA, and stiffness index obtained by QUS were significantly lower in the OA group than in controls. CONCLUSION: Higher BMDs of the spine and radius suggest that the incidence of osteoporosis is inversely associated with the incidence of OA. However, it remains unclear whether lack of difference in BMD and lower SOS, BUA, and stiffness index of the calcaneus in the OA group was secondary to the effect walking disturbance resulting from hip pain. Our data suggest that hip OA patients have higher BMD than healthy women, and that inactivity or immobilization caused by hip OA may reduce BMD in the lower limb.

Discrepancy in bone mineral densities at different skeletal sites in hip osteoarthritis patients.

OBJECTIVE: Increased femoral neck bone mineral density (BMD) in a hip with osteoarthritis (OA) has been previously reported, however, it is possible that increased BMD at sites other than the hip joint is influenced by the disease process of OA. Therefore, we measured BMD at locations different from the hip joint and determined whether higher BMD was also observed at these different skeletal sites in hip OA patients. METHODS: We measured BMD in 68 women (average age 61.0 years) scheduled to undergo total hip arthroplasty for end-stage OA and 100 healthy women (average age 60.9 years) as age-matched controls. BMD at the lumbar spine, radius, and calcaneus was measured by dual-energy X-ray absorptiometry (DXA). Moreover, we measured speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index of the calcaneus by quantitative ultrasonography (QUS). RESULTS: BMD obtained by DXA at the lumbar spine and radius was significantly higher in hip OA patients than in controls. However, at the calcaneus, no significant differences were observed between the groups in BMD obtained by DXA. SOS, BUA, and stiffness index obtained by QUS were significantly lower in the OA group than in controls. CONCLUSION: Higher BMDs of the spine and radius suggest that the incidence of osteoporosis is inversely associated with the incidence of OA. However, it remains unclear whether lack of difference in BMD and lower SOS, BUA, and stiffness index of the calcaneus in the OA group was secondary to the effect walking disturbance resulting from hip pain. Our data suggest that hip OA patients have higher BMD than healthy women, and that inactivity or immobilization caused by hip OA may reduce BMD in the lower limb.

Formation of chiral environments by a mechanical induced vortex flow.

A chiral molecule absorbs preferentially right- or left-handed circularly polarized light in a circular dichroism (CD) measurement. Usually, the chirality of individual molecules is regarded as the origin of the CD signals. However, recently, several reports have suggested that the vortex flow of a solution of an achiral molecule gives rise to a CD signal, which is dependent on the stirring direction. This article introduces types of molecular architecture and material designs that show stir-induced chirality. We also discuss the effects of the molecular structure and alignment in vortex flows on this phenomena, reviewing the related issues.

Bone mineral density is not related to heterotopic ossification after total hip arthroplasty.

PURPOSE: Heterotopic ossification (HO) after total hip arthroplasty (THA) is a frequent complication that compromises the success of this procedure; however, its precise pathogenesis is unknown. Patient-related risk factors have previously been investigated to predict patients likely to have HO. In this study, we compared bone mineral density (BMD) between patients with and without HO after THA. METHODS: We measured BMD of the lumbar spine, radius, and calcaneus using dual-energy X-ray absorptiometry in 98 females who were scheduled to undergo THA. Radiographs were graded for the presence of HO according to the criteria of Brooker at a minimum follow-up of two years following THA. BMD were compared between those with HO and those without. RESULTS: In total, HO was observed in 20 of 98 hips. There were no significant differences in age, height, weight, body mass index, and pre-operative total hip score between the HO and non-HO groups. No significant difference was observed in BMD of the lumbar spine, distal radius, mid-radius, and calcaneus between the two groups. CONCLUSIONS: Our findings suggest that generalized BMD is not related to the occurrence of HO after THA in women.

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia.

BACKGROUND: We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed. METHODS: Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval. RESULTS: The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males. CONCLUSIONS: These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Circularly polarized luminescence of rhodamine†B in a supramolecular chiral medium formed by a vortex flow.

Sucked into the vortex: Hydrogels with embedded Rhodamine B dye showed stir-induced circularly polarized luminescence (CPL; see picture), the sense of which can be controlled by switching the stir direction from clockwise (CW) to counterclockwise (CCW) with slow cooling from the sol to gel states. The chiral alignment of the dye was erased by heating the sample above the gel-sol transition temperature.

Brothers with novel compound heterozygous mutations in COL27A1 causing dental and genital abnormalities.

COL27A1 encodes a collagen type XXVII alpha 1 chain. It is the product of this gene that provides the structural support of connective tissue and is reported to be the causative gene of Steel syndrome (OMIM #615155). The primary symptoms of patients with this defect are consistent with systemic bone disease; however, recent reports note findings of intellectual disability and hearing loss. In this study, we identified novel COL27A1 compound heterozygous variants in two brothers with rhizomelia and congenital hip dislocation as well as dental and genital abnormalities that have not yet been reported in Steel syndrome. This variant, of maternal origin, caused an amino acid substitution of arginine for glycine, c.2026G>C or p.G676R, in the collagen helix domain, which is assumed to damage the structure of the helix. The paternally transmitted variant, c.2367G>A, is located at the 3' end of exon 12, and cDNA analysis revealed a splicing alteration. These novel, compound heterozygous COL27A1 variants might indicate an association of the gene with tooth and genital abnormalities.

Revision with impacted bone allografts and the Kerboull cross plate for massive bone defect of the acetabulum.

We retrospectively reviewed 31 hips with massive bone defect because of aseptic loosening of the acetabulum treated with impacted bone allografts with the Kerboull-type acetabular device. Mean age at surgery was 67.9 years, and mean duration of follow-up was 6.3 years. Thickness of the bone graft was evaluated by postoperative radiography. Seven hips showed radiological failure associated with 6 breakages of the device, and 24 hips showed stability on follow-up radiographs. Of the 13 hips showing a bone graft thickness of greater than 20 mm on follow-up radiographs, 7 were classified as failure group. If an acetabular reinforcement device with a bone graft of more than 20 mm thickness is necessary, then a structural allograft should be considered in the weight-bearing area of the support ring in addition to the morselized bone graft.

Analysis of interobserver reliability for radiographic staging of coxarthrosis and indexes of acetabular dysplasia: a preliminary study.

BACKGROUND: We are planning a multicenter survey on coxarthrosis and acetabular dysplasia in Japan. To collect reliable data, we performed a preliminary study to elucidate the observer agreement on assessment items. METHODS: We collected radiographs of hip joints in eight patients with various findings of coxarthrosis. Twelve registered orthopedic specialists evaluated them regarding the roentgenographic stage of coxarthrosis and five indexes of acetabular dysplasia (acetabular angle, center-edge angle, acetabular roof obliquity, acetabular head quotient, approximate acetabular quotient). To assess observer agreement, we calculated the value of the kappa statistic for stages and the coefficient of variation for the indexes. The same 12 specialists then assessed the coxarthritis stage on the same radiographs 1 month after the first evaluation based on our own descriptions of the roentgenographic stages. RESULTS: For the first evaluation of the roentgenographic stage, the value of the kappa statistic was 0.448; and for the second evaluation it was 0.600. The results of the coefficient of variation for the indexes of acetabular dysplasia, ranked in ascending order, were as follows: acetabular angle, acetabular head quotient, acetabular roof obliquity, center-edge angle, approximate acetabular quotient. CONCLUSIONS: For the upcoming multicenter survey, clear descriptions of the stages of coxarthrosis and selection of appropriate indexes can be helpful for collecting dependable results.

Joint congruency in abduction before surgery as an indication for rotational acetabular osteotomy in early hip osteoarthritis.

We conducted a retrospective review of the results of rotational acetabular osteotomy (RAO) procedures in 92 hips of 89 patients (81 females and eight males) with early-stage osteoarthritis. In this study, we discuss the indications for this surgery based on the preoperative congruency in abduction. The mean postoperative follow-up was 12.2 (7-19) years. The mean age at operation was 32.5 (13-54) years. Two hips with apparent technical failure were excluded. During follow-up, the osteoarthritic stage remained unchanged in 76 hips (good group) and progressed in 14 hips (poor group). Preoperative joint congruency in abduction was excellent in 20 hips, good in 62, and fair in eight. All eight hips with fair joint congruency showed progression to osteoarthritis at follow-up. Patients without good congruency in abduction may experience progression of osteoarthritis after RAO procedures even in early-stage osteoarthritis.

Light-induced deformation of photoresponsive liquid crystals on a water surface.

Photodeformation: Azobenzene derivatives showing a room-temperature liquid crystal (LC) phase exhibit photoinduced deformation on a water surface. While a droplet of a LC sample floating on the surface expands upon UV irradiation, a LC sample containing a solvent is condensed towards the center of the illuminated regions (see figure).

Joint congruency as an indication for rotational acetabular osteotomy.

UNLABELLED: Long-term results of periacetabular osteotomy for advanced-stage osteoarthritis secondary to developmental dysplasia of the hip are reportedly unsatisfactory compared with results for early-stage osteoarthritis. Other preoperative information that can be used to determine indications for periacetabular osteotomy is therefore important to avoid performing osteotomy in young patients with advanced-stage osteoarthritis who would not likely achieve substantial benefit. We retrospectively reviewed 47 patients (49 hips) with advanced-stage osteoarthritis who underwent rotational acetabular osteotomy (RAO) using preoperative congruency in abduction. The minimum postoperative followup was 8 years (mean, 12.3 years; range, 8-20 years) and mean age at surgery was 43.1 years (range, 30-59 years). At followup, osteoarthritic stage was improved in 12 hips, unchanged in 24 hips, and had progressed in 13 hips. Preoperative joint congruency in abduction was good in 13 hips, poor in 32 hips, and narrowed in four hips. Patients with better congruency in abduction had better results. We believe osteoarthritis with good congruency in abduction preoperatively remains a good indication for RAO even in advanced stages of disease. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Long-term outcome of Ludloff's medial approach for open reduction of developmental dislocation of the hip in relation to the age at operation.

We reviewed long-term outcomes after open reduction by the medial approach for developmental dislocation of the hip (DDH). Forty-five hips in 43 patients with more than ten years of follow-up were assessed clinically and radiologically. The mean age at surgery was 14.0 (range 6-31) months, and the follow-up period ranged from ten to 28 years (mean 16.4 years). We compared the good (18 hips) and poor groups (27 hips) as classified by the Severin classification. The mean age at surgery was significantly older in the poor group than the good group (17.1 and 9.4 months, respectively, P < 0.001). Thirteen (29%) of 45 hips had avascular necrosis (AVN) of the femoral head. The mean age at surgery was significantly older in the patients with AVN than without AVN (20.0 and 11.6 months, respectively, P < 0.001). Another approach, such as the wide exposure method, should be selected for DDH with increased age at operation.

Radiographic joint space width in patients with Crowe Type-I dysplastic hips.

UNLABELLED: Radiographic evaluation of preoperative joint space width is believed important to predict the long-term results of osteotomy. We asked whether joint space width differs in the supine and standing positions in patients with Crowe Type-1 osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH). Joint space width was measured in the supine and standing positions in 146 women and 16 men (231 hips) with OA. Subjects had a mean age of 46.7 years (range, 22-59 years). Differences were seen on radiographs in joint space width between supine (2.35 +/- 1.65 mm; range, 0.1-6.2 mm) and standing (2.04 +/- 1.78 mm; range, 0.0-5.9 mm). In 27 of 172 hips with greater than 1 mm joint space in the supine position, joint space width was decreased by greater than 1 mm in the standing position. To evaluate preoperative joint space width in patients scheduled for osteotomy, radiographs should be obtained with the patient in the standing position. LEVEL OF EVIDENCE: Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Femoral head deformity after open reduction by Ludloff's medial approach.

Ludloff's medial approach has been described as a simple procedure for open reduction of developmental dysplasia of the hip (DDH) requiring minimal dissection and tissue disruption. Many patients undergo subsequent reconstruction of the acetabulum after skeletal maturity for residual dysplasia. Femoral head deformity reportedly influences the long-term outcome of these osteotomies. The literature suggests this deformity may be related to the patient's age at the time of a medial approach. We therefore asked whether femoral head deformity (roundness index, femoral head enlargement) at skeletal maturity correlates with patient age at surgery. We assessed the radiographs of 40 patients (42 hips). Their mean age at surgery was 14.3 months (range, 6-31 months); the minimum followup was 10 years (mean, 15.8 years; range, 10-27 years). The mean roundness index at skeletal maturity correlated with increased age at the time of the operation (mean index, 58.3; range, 47-79) while enlargement did not. Using a medial approach for correction of DDH in older patients increases the risk of femoral head deformity at skeletal maturity.

Rotational acetabular osteotomy with excision of the capital drop for advanced osteoarthritis secondary to developmental dysplasia of the hip.

INTRODUCTION: Advanced-stage osteoarthritis may occasionally be associated with capital drop of the femoral head. In such cases, excision of the capital drop is performed to obtain good congruency with sufficient coverage of the femoral head by rotational acetabular osteotomy (RAO). In the present study, we examined the outcome of RAO with excision of the capital drop. MATERIALS AND METHODS: Rotational acetabular osteotomy (RAO) with excision of the capital drop was performed in 17 hips of 16 patients with a mean follow-up of 12.6 years (excision group), while only RAO was performed in 42 hips of 41 patients with a mean follow-up of 12.3 years (non-excision group). All 57 patients indicated radiographic evidence of advanced-stage osteoarthritis. Clinical follow-up was performed using the Merle d'Aubigné and Postel system. The clinical and radiological results were compared between the two groups. RESULTS: The mean Merle d'Aubigne and Postel's total hip-joint scores at follow up significantly (p < 0.001) improved compared with the mean pre-operative scores only in the non-excision group. While the numbers of hips in excision group (17 hips) showing progressive and non-progressive osteoarthritic changes were 10 and 7, those in the non-excision group (42 hips) were 11 and 20, respectively. Although none (0/17) in the excision group showed any improvement in osteoarthritic stage at follow up, 11 of 42 hips indicated a favorable outcome in the non-excision group. There were significantly (p = 0.0077) higher improvements in osteoarthritis stage in the non-excision than excision group. Three patients each of the excision group (18%) and non-excision group (7%) underwent total hip arthroplasty during the follow-up period. CONCLUSION: Excision of capital drop of the femoral head is not a useful adjunct to the RAO procedure for the treatment of advanced osteoarthritis. Based on results from a previous study, Chiari pelvic osteotomy may serve as a more favorable alternative.

Outcome of rotational acetabular osteotomy for early hip osteoarthritis secondary to dysplasia related to femoral head shape: 49 hips followed for 10-17 years.

BACKGROUND: Hip osteoarthritis in Japanese patients is in most cases secondary and purpose to congenital dislocation of the hip or acetabular dysplasia - often associated with a deformed femoral head. Thus, we examined the outcome of rotational acetabular osteotomy (RAO) procedures in patients with early-stage osteoarthritis secondary to developmental dysplasia of the hip, and its relationship to femoral head deformity. PATIENTS AND METHODS: We retrospectively reviewed the outcome of RAO procedures in 49 hips of 48 patients (43 females). All patients had radiographic evidence of early-stage osteoarthritis. The mean age was 33 (13-54) years at surgery, and the mean duration of follow-up was 13 (10-17) years. The roundness index of the femoral head was measured on preoperative radiographs. Clinical follow-up was performed using the Merle d'Aubigné and Postel system. RESULTS: The mean preoperative clinical score was 13 points; this had improved to 17 points at the most recent follow-up (p < 0.001). Radiographically, this procedure gave adequate improvement of femoral head coverage. At follow-up, stage of osteoarthritis was unchanged in 38 hips and had progressed in 11 hips. 2 of the 11 hips with progression of the osteoarthritic stage had obvious technical failure and were excluded from subsequent comparisons. The mean preoperative round index of the femoral head was different for the 38 hips with no obvious progression than for the 9 hips that showed progression (55% and 68%, respectively; p < 0.001). INTERPRETATION: Patients with a deformed femoral head may experience progression of osteoarthritis within 10 years of the RAO procedure, even in early-stage osteoarthritis.