In Vivo Postoperative Motion of Fixed and Mobile Medial Pivot Knees Under Weight-Bearing Conditions after Cruciate-Sacrificing Total Knee Arthroplasty.

BACKGROUND: In vivo three-dimensional (3D) motion under weight-bearing conditions was analyzed postoperatively in medial pivot cruciate-substituting (CS) knee systems with fixed and mobile inserts. METHODS: Tibiofemoral knee kinematics during squatting were captured with X-ray fluoroscopy for 4 patients in each cohort. The 3D motion of implants was analyzed with KneeMotion motion analysis software (LEXI Corporation; Tokyo, Japan). In addition, anterior-posterior (AP) movement of the distal-most points and the angle of axial rotation of the femoral component on the tibial component were assessed in both cohorts. RESULTS: Mean AP movement of the femoral component on the tibial component was 3.8±0.5 mm on the medial side and 9.5±0.5 mm on the lateral side in the cohort with fixed prostheses and 5.9±2.1 mm on the medial side and 10.0±2.5 mm on the lateral side in the cohort with mobile prostheses. The mean angle of axial rotation of the femoral component on the tibial component was 14.4±1.1 degrees and 8.2±2.7 degrees of external rotation for fixed knees and mobile knees, respectively. CONCLUSIONS: Postoperative motion analysis confirmed that fixed and mobile CS implants, which have a similar design, guided medial pivot motion under weight-bearing conditions. However, motion differed between these implant types after mid-flexion: bicondylar rollback after medial pivot motion was noted in the mobile cohort.

Bone microstructure changes due to once-/twice-weekly teriparatide administration: A report of five cases using high-resolution peripheral quantitative computed tomography.

This study was conducted with the aim of presenting cases in which high-resolution peripheral quantitative computed tomography (HR-pQCT) was used to investigate changes in the bone microstructure due to once-weekly/twice-weekly administration of teriparatide (TPTD). Of osteoporosis patients who participated in a non-inferiority trial (TWICE study: once-weekly vs twice-weekly TPTD) with lumbar bone mineral density as the primary endpoint, five cases scanned by HR-pQCT before TPTD administration were analysed. Two cases were given once-weekly TPTD, three were given twice-weekly TPD, and HR-pQCT was repeated after 48 weeks. A sufficient anabolic effect of once-weekly/twice-weekly TPTD on the trabecular and cortical bone at the tibia was obtained. In addition, the average change in cortical porosity (Ct.Po) was only 0.3% in the tibia and 0.2% in the radius. These findings indicate that once-weekly and twice-weekly TPTD can be expected to improve the bone microstructure, and the increase in Ct.Po may be suppressed.

Daily activity relates to not only femoral bone mineral density, but also hip structural analysis parameters: A cross-sectional observational study.

OBJECTIVES: Physical activity to maintain bone mass and strength is important for hip fracture prevention. We aim to investigate the relationship between physical performance/activity status and bone mineral density (BMD)/hip structural analysis (HSA) parameters among postmenopausal women in Japan. METHODS: Sixty-two postmenopausal women diagnosed with osteoporosis (mean age: 72.61 ± 7.43 years) were enrolled in this cross-sectional observational study. They were evaluated for BMD and HSA in the proximal femur by dual-energy X-ray absorptiometry and underwent several physical performance tests, the Geriatric Locomotive Function Scale of 25 questions (GLFS-25). Principal component analysis (PCA) was used to summarize data on the BMD/HSA parameters. Partial correlation analysis, multiple regression analysis, and structural equation modeling (SEM) were performed to investigate the relationship between physical performance/activity status and BMD/HSA parameters of the proximal femur. RESULTS: In a partial correlation analysis adjusted for age and body mass index (BMI), GLFS-25 scores were correlated with HSA parameter (|r| = 0.260-0.396, P < 0.05). Principal component 1 (PC1) calculated by PCA was interpreted as more reflective of bone strength based on the value of BMD/HSA parameters. The SEM results showed that the model created by the 3 questions (Q13, brisk walking; Q15, keep walking without rest; Q20, load-bearing tasks and housework) of the GLFS-25 had the best fit and was associated with the PC1 score (ß = -0.444, P = 0.001). CONCLUSIONS: The GLFS-25 score was associated with the BMD/HSA parameter, which may reflect the bone strength of the proximal femur as calculated by PCA.

Efficacy of non-steroidal anti-inflammatory drugs on zoledronic acid-induced acute-phase reactions: randomized, open-label, Japanese OZ study.

INTRODUCTION: Zoledronic acid infusion is used to treat osteoporosis but patients, especially Japanese patients, often experience acute-phase reactions (APRs). In this multicenter, randomized, open-label, parallel-group study, we examined the efficacy of the most commonly used non-steroidal anti-inflammatory drug loxoprofen in Japan in reducing the incidence rate of zoledronic acid-induced APRs and body temperature, and investigated risk/protective factors for APRs in this population. MATERIALS AND METHODS: Patients aged ≥ 60 years with primary osteoporosis (n = 368) were allocated randomly to zoledronic acid plus loxoprofen (ZOL + LOX) or zoledronic acid alone (ZOL). All patients received 5-mg zoledronic acid infusion on day 1, and patients in the ZOL + LOX group also received 120 mg and 180 mg of oral loxoprofen on days 1 and 2, respectively. Adverse events and body temperature were recorded during the 7-day observation period. RESULTS: The incidence rates of APRs were 34.4% (64/186 patients) and 47.8% (87/182 patients) in the ZOL + LOX and ZOL groups, respectively (P = 0.0109). The proportions of patients with increased body temperature (≥ 1 °C and ≥ 37.5 °C) were similar in both groups (P = 0.1186). Past bisphosphonate users had a significantly lower incidence rate of APRs than treatment-naïve patients (odds ratio 0.444, 95% confidence interval 0.285-0.692, P = 0.0003). CONCLUSIONS: Zoledronic acid-induced APRs appeared to be suppressed by loxoprofen. Known risk/protective factors, including prior osteoporosis treatment, were applicable to Japanese patients.

The relationship between the lesion-to-ankle articular length ratio and clinical outcomes after bone marrow stimulation for small osteochondral lesions of the talus.

PURPOSE: The purpose of this study was to determine the relationship between the defect-to-ankle articular length ratio and clinical outcomes after arthroscopic bone marrow stimulation. METHODS: Seventeen male and 24 female patients (mean age 36.0 years, height 160.7 cm, weight 62.5 kg, body mass index 24.0) with an osteochondral lesion of the talus were treated with arthroscopic bone marrow stimulation and assessed using the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale, Berndt and Harty scales and clinical outcome criteria. The lengths of the tibial and talar articular surfaces were defined from the anterior tip to posterior tip of the articular cartilage on sagittal magnetic resonance imaging scans. The size of the defect area was defined and determined for each patient on magnetic resonance images using coronal length, sagittal length, and area. The relationship between clinical outcome and sagittal tibia ratio (sagittal length of defect/length of tibia articular cartilage) and sagittal talus ratio (sagittal length of defect/length of talus articular cartilage) were assessed. RESULTS: The mean lesion length was 11 mm (range 6-14 mm), lesion size was 67 mm(2) (range 19-134 mm(2)), sagittal tibia ratio was 0.42 (range 0.21-0.75), and sagittal talus ratio was 0.32 (range 0.16-0.58). The mean JSSF scale improved from 74 (range 18-90) to 89 (range 67-100) postoperatively. Lesion area was not associated with the JSSF scale (r = -0.10, P = 0.52). Talus articular length (r = 0.64, P < 0.0001) and tibia articular length (r = 0.64, P < 0.0001) were correlated with patient height. The sagittal talus ratio and sagittal tibia ratio were not associated with the JSSF scale (r = -0.10, P = 0.55; r = -0.02, P = 0.90). CONCLUSION: Arthroscopic bone marrow stimulation provides good clinical outcomes in small osteochondral lesions of the talus (<15 mm). For small lesions, the lesion size is not a prognostic factor. LEVEL OF EVIDENCE: IV: Retrospective Case Series.