Other. The purpose of the present study was to analyze the violation of statistical independence in recent orthopaedic research papers and to demonstrate the effect of statistical analysis that considered the data dependency within a subject. Methods: First, all original articles that had been published in The Journal of Bone and Joint Surgery (American Volume) over a two-year period were evaluated. The analysis was designed to identify articles that included bilateral cases and possible violations of statistical independence. Second, a demonstrative logistic regression without consideration of statistical independence was performed and was compared with a statistical analysis that considered data dependency within a subject. Radiographs of 1200 hips in 600 patients were used to examine the differences in terms of odds ratios (with 95% confidence intervals) of the risk factors for hip osteoarthritis. Results: Four hundred and eighty-six original articles were reviewed, and 151 articles (including forty-one articles involving the hip, thirty-four involving the knee, twenty-one involving the foot or ankle, nineteen involving the shoulder, ten involving the hand or wrist, nine involving the elbow, and seventeen involving other structures) were considered to include bilateral cases. Of the 486 articles that were reviewed, 120 articles (25%) (including thirty-six articles involving the hip, twenty-six involving the knee, fifteen involving the foot or ankle, fourteen involving the shoulder, seven involving the elbow, six involving the hand or wrist, and sixteen involving other structures) were found to have possibly violated statistical independence. Demonstrative statistical analysis showed that logistic regression was not robust to the violation of statistical independence. The 95% confidence intervals of the odds ratios for the risk factors showed narrower ranges (1.13 to 2.68 times) when data dependency within a subject was not considered. Conclusions: Researchers need to consider statistical independence when performing statistical analysis, particularly in studies involving bilateral cases. If data dependency within a subject is not considered, studies involving bilateral cases can bias results, depending on the context of those studies....

Won SH, et al. Yonsei Med J. 2014 Sep;55(5):1373-1378. http://dx.doi.org/10.3349/ymj.2014.55.5.1373

Background: The purpose of this study was to analyze kinematic trunk motion data in normal adults and to investigate gender effect. Methods: Kinematic trunk motion data were obtained for 20 healthy subjects (11 men and 9 women; age from 21 to 40 years) during walking a 9 m long lane at a self selected speed, namely, motions in the sagittal (tilt), coronal (obliquity), and transverse (rotation) planes, which were all expressed as motions in global (relative to the ground) and those in pelvic reference frame (relative to pelvis), i.e., tilt (G), obliquity (G), rotation (G), tilt (P), obliquity (P), rotation (P). Results: Range of tilt (G), obliquity (G) and rotation (G) showed smaller motion than that of tilt (P), obliquity (P) and rotation (P), respectively. When genders were compared, female trunks showed a 5 degree more extended posture during gait than male trunks (p = 0.002), which appeared to be caused by different lumbar lordosis. Ranges of coronal and transverse plane motion appeared to be correlated. In gait cycle, the trunk motion appeared to counterbalance the lower extremity during swing phase in sagittal plane, and to reduce the angular velocity toward the contralateral side immediate before the contralateral heel strike in the coronal plane. Conclusions: Men and women showed different lumbar lordosis during normal gait, which might be partly responsible for the different prevalence of lumbar diseases between genders. However, this needs further investigation.

Background: Several 3D multi‐segment foot models (MFMs) have been introduced for the in vivo analysis of dynamic foot kinematics. However, reproducibility of a model should be checked and ascertained before clinical utilization of a MFM. The purpose of this study was to determine the reliability of recently introduced MFM with a 15‐marker set by assessing the participant's stride‐to‐stride (intra‐session) and visit‐to‐revisit (inter‐session) repeatability.Methods: Twenty healthy adults with a mean age of 28.9 years (10 males and 10 females) were tested. Three representative strides from five separate trials were used for analysis from each session. Kinematic data of foot segmental motion was collected and tracked using the Foot3D Multi‐Segment Software (Motion Analysis Co., Santa Rosa. CA). A retest was performed in the same manner at an interval of 4 weeks. Coefficients of multiple correlation (CMC) and intra‐class correlation coefficient (ICC) were calculated in order to assess the intra‐session and inter‐session repeatability.Results: Inter‐segment foot angles from healthy adults from a MFM with 15‐marker set showed a narrow range of variability during the gait cycle. The mean intra‐session ICC was 0.981 (±0.010), which was interpreted as excellent. The mean intra‐session CMC was 0.948 (±0.027), which was interpreted as very good repeatability. The mean inter‐session ICC was 0.886 (±0.047) and the mean inter‐session CMC was 0.801 (±0.077), which were interpreted as excellent and good repeatability, respectively.Conclusion: We demonstrated a MFM with a 15‐marker set had high intra‐session and inter‐session repeatability, especially in sagittal plane motion. We thought this MFM would be applicable to evaluation of the segmental foot motion during gait.

Background: The relationship between torsional bony deformities and rotational gait parameters has not been sufficiently investigated. This study was to investigate the degree of contribution of torsional bony deformities to rotational gait parameters in patients with diplegic cerebral palsy (CP). Methods: Thirty three legs from 33 consecutive ambulatory patients (average age 9.5 years, SD 6.9 years; 20 males and 13 females) with diplegic CP who underwent preoperative three dimensional gait analysis, foot radiographs, and computed tomography (CT) were included. Adjusted foot progression angle (FPA) was retrieved from gait analysis by correcting pelvic rotation from conventional FPA, which represented the rotational gait deviation of the lower extremity from the tip of the femoral head to the foot. Correlations between rotational gait parameters (FPA, adjusted FPA, average pelvic rotation, average hip rotation, and average knee rotation) and radiologic measurements (acetabular version, femoral anteversion, knee torsion, tibial torsion, and anteroposteriortalo-first metatarsal angle) were analyzed. Multiple regression analysis was performed to identify significant contributing radiographic measurements to adjusted FPA. Results: Adjusted FPA was significantly correlated with FPA (r=0.837, p<0.001), contralateral FPA (r=0.492, p=0.004), pelvic rotation during gait (r=−0.489, p=0.004), knee rotation during gait (r=0.376, p=0.031), and femoral anteversion (r=0.350, p=0.046). In multiple regression analysis, femoral anteversion (p=0.026) and tibial torsion (p=0.034) were found to be the significant contributing structural deformities to the adjusted FPA (R²=0.247). Conclusions: Femoral anteversion and tibial torsion were found to be the significant structural deformities that could affect adjusted FPA in patients with diplegic CP. Femoral anteversion and tibial torsion could explain only 24.7% of adjusted FPA.

Neutralization of CTRP3 opposes degenerative tendon matrix remodeling during tendinopathy.