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 (ß=0.37; p=0.022), KOOS subscale for activities of daily living (ß=0.42; p=0.0096), and OKS (ß=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.

Unicompartmental Knee Arthroplasty for Osteoarthritis Eliminates Lateral Thrust: Associations between Lateral Thrust Detected by Inertial Measurement Units and Clinical Outcomes.

The purpose of this study was to investigate the relationship between clinical outcomes and lateral thrust before and after unicompartmental knee arthroplasty (UKA) using inertial measurement sensor units. Eleven knees were evaluated with gait analysis. The varus angular velocity was used to evaluate lateral thrust. The femorotibial angle (FTA) and hip-knee-ankle angle (HKA) were used to evaluate lower-limb alignment, and the Oxford Knee Score (OKS) and Japanese Orthopaedic Association Score (JOA) were used to evaluate clinical outcomes. The mean pre-UKA peak varus velocity was 37.1 ± 9.8°/s, and that for post-UKA was 28.8 ± 9.1°/s (p = 0.00003), such that instabilities clearly improved. Assuming the definition of lateral thrust is when the varus angular velocity is more than 28.1°/s, 81.8% of patients had lateral thrust preoperatively, but this decreased to 55.6% postoperatively, such that the symptoms and objective findings improved. Both OKS and JOA improved after surgery. In addition, HKA was -7.9° preoperatively and -5.8° postoperatively (p = 0.024), and FTA was 181.4° preoperatively and 178.4° postoperatively (p = 0.012). There was a positive correlation between postoperative JOA and FTA, indicating that changes in postoperative alignment affected clinical outcomes. This study quantitatively evaluated the disappearance of lateral thrust by UKA, and it found that the stability can be achieved by UKA for unstable knees with lateral thrust.

Preventing Loss of Femoral Periprosthetic Bone Mineral Density in Cementless Total Hip Arthroplasty Using a Tapered Wedge Stem: A Retrospective, Cohort Study in Osteoporotic Patients Treated with Denosumab.

Purpose: Bone quality is an important issue in elderly osteoporotic patients who undergo total hip arthroplasty (THA) because periprosthetic fracture or aseptic loosening of implant caused by periprosthetic bone loss is a serious concern. Denosumab has been approved for osteoporosis patients. Thus, the purpose of this study was to investigate whether denosumab prevents loss of proximal femoral periprosthetic bone mineral density (BMD) in cementless THA using a tapered wedge stem in patients with osteoporosis. Methods: Seventy consecutive patients who had undergone primary THA were included in this study. Twenty-seven patients who received denosumab for osteoporosis formed the denosumab group, and 43 patients without denosumab formed the control group. Bone turnover markers and femoral periprosthetic BMD were measured at two weeks, six months, and 12 months after THA. BMD was evaluated in seven regions of interest according to the zones of Gruen. Results: BMD in zone 1 was significantly increased from baseline at both six and 12 months after THA in the denosumab group (10.0±10.2%, p<0.001 and 13.1±12.7%, p<0.001, respectively) and significantly decreased in the control group (-3.6±9.7%, p<0.05, and -5.9±9.4%, p<0.001, respectively). BMD in zone 7 was significantly decreased compared to baseline at both six and 12 months after THA in the control group (-19.2±20.2%, p<0.001 and -22.3±16.8%, p<0.001, respectively) but not in the denosumab group (-0.7±18.5% and -1.1±16.6%, respectively). The use of denosumab for THA patients with osteoporosis was independently related to preventing loss of periprosthetic BMD of the femur at 12 months after surgery in zones 1 (p<0.001) and 7 (p<0.001) on multivariate analysis. Conclusions: Denosumab significantly increased proximal femoral periprosthetic BMD in zone 1 and prevented loss of BMD in zone 7 in patients with osteoporosis after cementless THA using a tapered wedge stem at both seven and 12 months. Future studies of denosumab treatment following THA in patients with osteoporosis should focus on clinical outcomes such as the risk of periprosthetic fracture and revision THA.

Pediatric femoral shaft fracture requiring revision surgery for nonunion associated with vitamin D and K deficiencies: a case report.

BACKGROUND: Nonunion of femoral shaft fractures in children is rare, and there is no clear treatment protocol. In this case report, a pediatric femoral shaft fracture that developed in nonunion due to vitamin deficiency after osteosynthesis, which was successfully treated with vitamin augmentation and replacement with a rigid antegrade intramedullary nail, is described. CASE PRESENTATION: The patient is an 11-year-old Japanese girl. She injured her right femoral shaft fracture when she hit a wall after kickboarding down a hill and underwent osteosynthesis with a titanium elastic nail. Six months postoperatively, she developed nonunion, was found to be deficient in vitamins D and K, and was started on vitamin supplementation. She underwent replacement with a rigid antegrade intramedullary nail at 7 months postoperatively, and bone union was achieved 3 months after reoperation. CONCLUSION: When delayed union of a fracture is observed postoperatively, even in children without underlying disease, the cause of the problem must be investigated and treated promptly.

Cardiac Tamponade Due to Intrapericardial Hernia Mimicking ST-Segment Elevation Myocardial Infarction.

Intrapericardial hernia is a diaphragmatic hernia that extremely rarely causes cardiac tamponade. We present a case of a cardiac tamponade caused by an intrapericardial hernia in a 78-year-old male patient with a history of coronary artery bypass grafting, mimicking ST-segment elevation myocardial infarction, which was successfully treated by emergent laparotomy.