Current Femoral Stem Fixation Selection in Hip-Fracture Bipolar Hemiarthroplasties, and Factors Affecting Surgeons’ Confidence in Their Ability to Teach about Cemented Stems: A Questionnaire in a Region of Japan with Super-Aged Patients

Japan’s hip fracture management guidelines now recommend the use of cemented stems in cases of bone fragility. However, the current stem selection practices in bipolar hemiarthroplasty (BHA) in a super-aging area in Japan remain unclear. This study aimed to examine the stem selection policies, the surgeons’ concerns about cemented stems, and factors affecting their confidence in their ability to coach others on cemented stem procedures. Ninety-four orthopedic surgeons (27 facilities) responded to our web-based questionnaire conducted in January/February 2022. Cementless stem was the first choice of 97.8% of the surgeons; <15% of the respondents expected to increase their use of cemented stems in the future. The cement technique was the greatest concern; almost half of the surgeons described having insufficient experience with cemented stems. The factor that most affected the surgeons’ expertise in using cemented stems is the number of surgeries they had conducted with a cemented stem (multivariable analysis odds ratio 8.42, p=0.001). Greater experience was associated with increased expertise of the surgeons in using cemented stems, with a threshold of 11 cases showing sensitivity of 41.7% and specificity of 98.3% for their confidence to instruct cemented stems

Massive Deposition and Accumulation of Hydroxyapatite Crystal after Total Hip Arthroplasty: A Case Report

We presented a case in which massive hydroxyapatite accumulation was observed around the artificial hip joint. A 66-year-old female showed a massive accumulation of fluid in and around the hip joint, and milk-like aspirate was obtained. Her aspirate culture was negative, and sediment analysis by X-ray diffraction showed that its component was hydroxyapatite. Since pain was mild, the patient was treated conservatively. To our knowledge, this is the first case in which liquid hydroxyapatite (milk of calcium) was accumulated around the artificial hip joint

Combined effect of teriparatide and low-intensity pulsed ultrasound for nonunion: a case report

BACKGROUND: Low-intensity pulsed ultrasound is a pain-free therapy performed daily at home by the patient and has been shown to promote fracture healing. Teriparatide is a parathyroid hormone preparation that activates osteoblastic bone formation and is also reported to be effective in promoting bony union. CASE PRESENTATION: We report the case of a 56-year-old Japanese male with a femoral shaft fracture who underwent intramedullary osteosynthesis nailing initially. He had no radiologic or clinical sign of healing 3 months later and low-intensity pulsed ultrasound was initiated at that time. He was reassessed in another 3 months, with evidence of mild bone consolidation but the fracture gap persisted. Subsequent treatment with human parathyroid hormone was initiated in combination with low-intensity pulsed ultrasound. Full fracture healing was present 6 months after beginning the combination low-intensity pulsed ultrasound and teriparatide. It is hypothesized that the potential additive effects of low-intensity pulsed ultrasound and teriparatide therapy ultimately triggered sufficient bone formation to support osseous union. CONCLUSION: The case reported herein is a femoral shaft atrophic nonunion in which traditional interventions failed. Successful fracture healing was finally achieved with low-intensity pulsed ultrasound and teriparatide therapy. This is the first reported case of diaphyseal nonunion with deterioration of bone quality in long bones resolved with teriparatide and low-intensity pulsed ultrasound

Potential of imaging analysis in establishing skin concentration-distance profiles for topically applied FITC-dextran 4 kDa

Quantitatively determining the skin concentration-distance profiles of topically applied drugs is important for evaluating their safety and efficacy. The aim of the present study was to quantitatively visualize the distribution of hydrophilic drugs through the skin using confocal laser scanning microscopy (CLSM) in order to obtain skin concentration-distance profiles. FITC-dextran with a molecular weight of approximately 4 kDa (FD-4) was selected as the model fluorescent drug in the present study, and excised pig ear skin was used. The skin concentration of FD-4 at each depth of a skin section was assessed by imaging analysis of the intensity of fluorescence. The FD-4 skin concentration-distance profile obtained was analyzed using Fick’s second law of diffusion, and was markedly similar to that using skin permeation parameters in the skin permeation study. These results suggest that the present CLSM method may be a promising tool for quantitatively visualizing the concentration-distance profiles of drugs through the skin

The Impact of Reduced Skeletal Muscle Mass on Patients with Knee Osteoarthritis

Although several studies have suggested a possible association between sarcopenia and knee osteoarthritis (OA) in the elderly, there remains no definitive evidence. Recently, however, the serum creatinine/cystatin C ratio (sarcopenia index: SI) was reported to correlate with skeletal muscle mass. The present retrospective study therefore investigated the impact of reduced skeletal muscle mass on advanced knee OA using SI. In 55 individuals scheduled for knee osteotomy or knee arthroplasty, correlations between SI and patient-reported outcomes such as the Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Oxford Knee Score (OKS) were explored. Significant associations were found between SI and the KSS functional activity score (β=0.37; p=0.022), KOOS subscale for activities of daily living (β=0.42; p=0.0096), and OKS (β=0.42; p=0.0095). This study underscores the role of reduced muscle mass in functional outcomes and introduces SI as a valuable marker for assessing muscle loss in knee OA patients

Allosteric regulation by cooperative conformational changes of actin filaments drives mutually exclusive binding with cofilin and myosin

Heavy meromyosin (HMM) of myosin II and cofilin each binds to actin filaments cooperatively and forms clusters along the filaments, but it is unknown whether the two cooperative bindings are correlated and what physiological roles they have. Fluorescence microscopy demonstrated that HMM-GFP and cofilin-mCherry each bound cooperatively to different parts of actin filaments when they were added simultaneously in 0.2 μM ATP, indicating that the two cooperative bindings are mutually exclusive. In 0.1 mM ATP, the motor domain of myosin (S1) strongly inhibited the formation of cofilin clusters along actin filaments. Under this condition, most actin protomers were unoccupied by S1 at any given moment, suggesting that transiently bound S1 alters the structure of actin filaments cooperatively and/or persistently to inhibit cofilin binding. Consistently, cosedimentation experiments using copolymers of actin and actin-S1 fusion protein demonstrated that the fusion protein affects the neighboring actin protomers, reducing their affinity for cofilin. In reciprocal experiments, cofilin-actin fusion protein reduced the affinity of neighboring actin protomers for S1. Thus, allosteric regulation by cooperative conformational changes of actin filaments contributes to mutually exclusive cooperative binding of myosin II and cofilin to actin filaments, and presumably to the differential localization of both proteins in cells