Ntative inpatient database to evaluate the impact of hospital volume on the rates of postoperative complications and in-hospital mortality after musculoskeletal tumor surgery. Methods: We used the Japanese Diagnostic Procedure Combination administrative database to retrospectively identify 4803 patients who had undergone musculoskeletal tumor surgery during 2007 to 2010. Patients were then divided into tertiles of approximately equal size on the basis of the annual hospital volume (number of patients undergoing musculoskeletal tumor surgery): low, twelve or fewer cases/year; medium, thirteen to thirty-one cases/year; and high, thirty-two or more cases/year. Logistic regression analyses were performed to examine the relationships between various factors and the rates of postoperative complications and in-hospital mortality adjusted for all patient demographic characteristics. Results: The overall postoperative complication rate was 7.2% (348 of 4803), and the in-hospital mortality rate was 2.4% (116 of 4803). Postoperative complications included surgical site infections in 132 patients (2.7%), cardiac events in sixty-four (1.3%), respiratory complications in fifty-one (1.1%), sepsis in thirty-one (0.6%), pulmonary emboli in sixteen (0.3%), acute renal failure in eleven (0.2%), and cerebrovascular events in seven (0.1%). The postoperative complication rate was related to the duration of anesthesia (odds ratio [OR] for a duration of more than 240 compared with less than 120 minutes, 2.44; 95% confidence interval [CI], 1.68 to 3.53; p < 0.001) and to hospital volume (OR for high compared with low volume, 0.73; 95% CI, 0.55 to 0.96; p = 0.027). The mortality rate was related to the diagnosis (OR for a metastatic compared with a primary bone tumor, 3.67; 95% CI, 1.66 to 8.09; p = 0.001), type of surgery (OR for amputation compared with soft-tissue tumor resection without prosthetic reconstruction, 3.81; 95% CI, 1.42 to 10.20; p = 0.008), and hospital volume (OR for high compared with low volume, 0.26; 95% CI, 0.14 to 0.50; p < 0.001). Conclusions: We identified an independent effect of hospital volume on outcomes after adjusting for patient demographic characteristics. We recommend regionalization of musculoskeletal tumor surgery to high-volume hospitals in an attempt to improve patient outcomes. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence....

Background: There is no consensus on whether mechanical alignment (MA) or kinematic alignment (KA) should be chosen for total knee arthroplasty (TKA) for coronal plane alignment of the knee (CPAK) Type I with a varus arithmetic HKA (aHKA) and apex distal joint line obliquity (JLO). The aim of this study was to investigate whether MA or KA is preferable for soft tissue balancing in TKA for this phenotype. Method: This prospective cohort study included 64 knees with CPAK Type I osteoarthritis that had undergone cruciate-retaining TKA. Using optical tracking software, we simulated implant placement in the Mako system before making the actual bone cut and compared the results between MA and KA. Extension balance (the difference between medial and lateral gaps in extension) and medial balance (the difference in medial gaps in flexion and extension) were examined. These gap differences within 2 mm were defined as good balance. Achievement of overall balance was defined as an attainment of good extension and medial balance. The incidence of balance in each patient was compared with an independent sample ratio test. Results: Compared with the MA group, the KA group achieved better soft tissue balance in extension balance (p < 0.001). A total of 75% of the patients in the KA group achieved overall balance, which was greater than the 38% achieved in the MA group (p < 0.001). Conclusions: In robot-assisted TKA for CPAK Type I osteoarthritis, KA achieved knee balance during extension without soft tissue release in a greater percentage of patients than MA.

We created SRC-1(-/-) mice by mating floxed SRC-1 mice with CMV-Cre transgenic mice. The SRC-1(-/-) mice showed high turnover osteopenia under physiological conditions and hardly responded to osteoanabolic actions of exogenous androgen and estrogen in males and females, respectively, after gonadectomies, indicating that SRC-1 is essential for the maintenance of bone mass by sex hormones. Steroid receptor coactivator-1 (SRC-1) is the first identified coactivator of nuclear receptors. This study investigated the role of SRC-1 in skeletal tissues of males and females using the deficient (SRC-1(-/-)) mice. SRC-1(-/-) mice were generated by mating our original floxed SRC-1 mice with CMV-Cre transgenic mice. Bone metabolism between 24-week-old SRC-1(-/-) and wildtype (WT) littermates under physiological conditions was compared in males and females by radiological, histological, and biochemical analyses. Difference of skeletal responses to steroid hormones was examined by gonadectomies and exogenous administration experiments with the hormones. Statistical analysis was performed by ANOVA determined by posthoc testing using Bonferroni's method. Although SRC-1(-/-) mice showed no abnormality in growth or major organs, both males and females showed osteopenia with high bone turnover in the trabecular bones, but not in the cortical bones, compared with WT littermates. Their serum levels of sex hormones were upregulated, suggesting a compensatory reaction for the insensitivity to these hormones. Gonadectomies caused decreases in BMDs of SRC-1(-/-) and WT mice to the same levels; however, replacement with 5 alpha-dihydrotestosterone and 17 beta-estradiol in males and females, respectively, failed to restore the bone loss in SRC-1(-/-), whereas the WT bone volume was increased to the sham-operated levels. In contrast, bone loss by administered prednisolone was similarly seen in SRC-1(-/-) and WT mice. We conclude that SRC-1 is essential for the maintenance of bone mass by sex hormones, but not for the catabolic action of glucocorticoid, under both physiological and pathological conditions.

Background: Hypermobility of the ulnar nerve from the cubital tunnel reportedly occurs in healthy people without symptoms of ulnar neuropathy. However, the occurrence rate in athletes is unknown. We examined the occurrence rate of ulnar nerve hypermobility using ultrasonography, symptoms, and physical findings in athletes and compared the results of four types of sports. Methods: Medical charts of college athletes competing in baseball, rugby, soccer, and long-distance running between March and November 2018 were retrospectively examined. Dynamic evaluation of the ulnar nerve was performed using ultrasonography and categorized as Types N, S, and D respectively, indicating normal position, subluxation, and dislocation. Subjective and objective findings were evaluated. Results: The present study included 246 male athletes (mean age, 19.7 years; 492 elbows) including 46% Type D, 29.8% Type S, and 24.2% Type N. Subjective findings showed pain and dysesthesia in 9% and 4.5% of participants, respectively, whereas objective findings showed Tinel sign in 6%, nerve tension test in 1.3%, Froment’s sign in 0.5%, and weakness of strength of opponens digiti minimi muscle in 8% of patients with Types D and S. Conclusions: There was a high-frequency hypermobility of the ulnar nerve from the cubital tunnel with or without subjective and objective findings in college athletes.