Anterior-posterior Mean Research Articles

Transbuccal sonographic evaluation of the local extent of tumors of the tongue with pathological correlation.

The object of this study was to evaluate the usefulness of preoperative transbuccal ultrasound (US) for the evaluation of tongue tumors. Thus, we evaluated the correlation between preoperative US measurements and postoperative pathologic measurements of tongue tumor size. From January 2003 to March 2011, 29 patients with tongue tumors were evaluated. All patients underwent preoperative transbuccal US at 1 day before surgery. Preoperative US was compared with pathology findings, including specimen size. The maximum anterior-posterior (AP) diameter of the long axis of the tumor, the maximum width (WD), and the maximum thickness (TH) of the tumor were measured with US along with a pathologic evaluation of the specimens. The mean AP was 22 ± 1 mm; WD was 13 ± 6 mm, and TH was 10 ± 5 mm using US. The pathologic mean AP was 21 ± 12 mm; WD was 12 ± 6 mm, and TH was 9 ± 4 mm. The Spearman's correlation coefficients of the AP, WD, and TH were 0.905 (p < 0.001), 0.918 (p < 0.001), and 0.971 (p < 0.001), respectively. Transbuccal US is a useful tool for predicting tongue tumor extent.

Anatomic Single-Bundle ACL Reconstruction Is Possible with Use of the Modified Transtibial Technique

Anatomic anterior cruciate ligament (ACL) reconstruction is essential to the restoration of normal knee kinematics and to achieving successful results after ACL surgery. The purpose of this study was to evaluate whether anatomic single-bundle ACL reconstruction can be performed with use of the modified transtibial technique such that the tunnel characteristics are not substantially different from those of the anteromedial transportal technique, with comparable clinical results. One hundred and four patients underwent single-bundle ACL reconstruction performed with use of either the modified transtibial technique or the anteromedial transportal technique. Each group included fifty-two patients retrospectively matched on the basis of age, sex, and body mass index. All patients had postoperative computed tomography (CT) and a minimum duration of follow-up of twenty-four-months. CT parameters, including tunnel position, tunnel length and shape, and graft obliquity, were evaluated. Clinical assessments were based on manual laxity tests, arthrometric analysis, and clinical scores recorded preoperatively and at the time of follow-up. The femoral tunnel was placed at a slightly inferior and anterior position with use of the modified transtibial technique compared with the anteromedial transportal technique, but the difference was not significant (superior-inferior mean [and standard deviation], 35.7% ± 3.1% versus 33.9% ± 4.1%, p > 0.05, and anterior-posterior mean, 31.6 ± 6.8% versus 35.1 ± 6.9%, p > 0.05, as assessed with use of the quadrant method). The femoral tunnel length was significantly longer (p < 0.05) and the tibial tunnel length was significantly shorter (p < 0.05) with use of the modified transtibial technique compared with the anteromedial transportal technique (mean femoral tunnel length, 40.5 ± 4.2 mm versus 34.4 ± 2.6 mm and mean tibial tunnel length, 32.3 ± 3.1 mm versus 35.5 ± 2.7 mm); however, tunnel length was sufficient to allow for adequate fixation. There were no significant differences between the two groups in terms of tibial tunnel position, graft obliquity, tibial tunnel widening, and clinical results. Tunnel characteristics including anatomic position, graft obliquity, and tunnel widening after single-bundle ACL reconstruction performed with use of the modified transtibial technique were not significantly different from those of the anteromedial transportal technique, and clinical results were comparable.

Anthropometric measurements of the human distal femur: a study of the adult Malay population.

The distal femurs of 100 subjects (50 men, 50 women) from the Malay population aged between 19 and 38 years were scanned to measure the anterior-posterior (AP) and medial-lateral (ML) width. The mean AP values were 64.02 ± 3.38 mm and 57.33 ± 3.26 mm for men and women, respectively, and the mean ML values were 74.91 ± 3.52 mm and 64.53 ± 3.07 mm. We compared our data to that published previously for the Chinese and Indian populations. It was found that the Malay population had smaller distal femur than that of the Chinese but was larger than that of the Indian population (P < 0.05). In conclusion, although it is well established that Asians have a smaller distal femur size than that of the Western population, the variations in different Asian ethnicities may need to be considered when designing the appropriate knee implant.

Hinged external fixator placement at the elbow: navigated versus conventional technique

Introduction: During the application of a hinged external elbow fixator, exact placement of the central pin remains difficult. Proper placement often necessitates multiple drilling attempts and fluoroscopic localization, which can be time consuming. We hypothesized that use of computerized navigation would enable a more precise placement of the central axis pin and would reduce the total number of drilling attempts.Materials and Methods: Twelve elbow models incorporating soft tissue coverage were used in this study. First, the optimal placement trajectory (OPJ) of the axis pin was defined in the anterior-posterior (AP) and lateral planes of the elbow. Six elbows were used with the navigation system and the axis pin was inserted in combination with a conventional fluoroscopy system under constant two-dimensional guidance from the virtual images. The pins for the remaining six elbow specimens were implanted conventionally under fluoroscopic guidance. The distances and angular deviations from the OPJ position were measured, and the results for the conventional placement and computer navigation groups were compared. To determine the definitive axis pin placement, a CT scan of each elbow with 1-mm slice thickness was used and the results were measured based on the defined optimal pin placement. AP plane angulations and lateral plane distances were calculated in relation to the optimal insertion trajectory for each specimen. Finally, we counted the overall number of drilling attempts needed to find the optimal position for the axis pin.Results: For the AP angulations, of the six elbows implanted using the conventional technique, half (n = 3) had deviations of ≥20° from the optimal axis. In contrast, in the navigated group, all cases (n = 6) were within 20° of the optimal axis in the AP plane. The mean AP angulation deviation in the conventional group was 20.5°, compared to 15° in the navigation group (p = 0.077). For the lateral distances, the mean distance from the drilling point to the point of optimal placement was 3.83 mm in the conventional group, versus 1.83 mm in the navigation group (p = 0.042). For all navigated cases, only one drilling attempt was necessary to achieve the desired position of the axial pin.Conclusion: Compared with the conventional method of axis pin placement for an elbow fixator, two-dimensional navigation allows a reduction in the number of drilling attempts required. Furthermore, the accuracy in terms of AP angulation and lateral distance from a defined optimal placement is better when compared to that obtained with the conventional technique.

Determining the preferred modality for real-time biofeedback during balance training

Vestibular rehabilitation therapy has been shown to improve balance and gait stability in individuals with vestibular deficits. However, patient compliance with prescribed home exercise programs is variable. Real-time feedback of exercise performance can potentially improve exercise execution, exercise motivation, and rehabilitation outcomes. The goal of this study is to directly compare the effects of visual and vibrotactile feedback on postural performance to inform the selection of a feedback modality for inclusion in a home-based balance rehabilitation device. Eight subjects (46.6±10.6years) with peripheral vestibular deficits and eight age-matched control subjects (45.3±11.1years) participated in the study. Subjects performed eyes-open tandem Romberg stance trials with (vibrotactile, discrete visual, continuous visual, and multimodal) and without (baseline) feedback. Main outcome measures included medial–lateral (M/L) and anterior–posterior mean and standard deviation of body tilt, percent time spent within a no-feedback zone, and mean score on a comparative ranking survey. Both groups improved performance for each feedback modality compared to baseline, with no significant differences in performance observed among vibrotactile, discrete visual, or multimodal feedback for either group. Subjects with vestibular deficits performed best with continuous visual feedback and ranked it highest. Although the control subjects performed best with continuous visual feedback in terms of mean M/L tilt, they ranked it lowest. Despite the observed improvements, continuous visual feedback involves tracking a moving target, which was noted to induce dizziness in some subjects with vestibular deficits and cannot be used during exercises in which head position is actively changed or during eyes-closed conditions.

Predictors of Three-Dimensional Breast Kinematics during Bare-Breasted Running

This study aimed to analyze differences in breast kinematics between breast cup sizes during running and the ability of breast and body size measurements to explain these differences. Forty-eight women (A to G cup; mean ± SD: age = 26.0 ± 6.0 yr, stature = 1.667 ± 0.064 m, mass = 62.78 ± 8.24 kg) with chest sizes of 32 to 38 inches participated. Chest and breast girths, a restricted anthropometric profile, suprasternal notch to nipple distances, and body mass index were measured, and breast mass was estimated. Multiplanar relative breast displacement, velocity, and acceleration during treadmill running were then recorded. Differences in breast kinematics were compared between cup sizes before and after allometric/polynomial scaling using significant breast and body size measures. All kinematic variables significantly increased with breast cup size (P < 0.05). Mean anterior-posterior (a/p), medial-lateral (m/l), and vertical bare-breasted displacements ranged from 0.030 to 0.059 m, from 0.018 to 0.062 m, and from 0.042 to 0.099 m, respectively, across A to G cups. Breast velocities ranged from 0.428 to 1.244 m·s(-1) (a/p), 0.411 to 1.708 m·s(-1)(m/l), and 0.819 to 2.174 m·s(-1) (vertical), respectively. Increases in breast acceleration varied from 11.664 to 48.438 m·s(-1) (a/p), 15.572 to 51.987 m·s(-1) (m/l), and 23.301 to 66.447 m·s(-1) (vertical), respectively. Scaling models found that breast mass was the only anthropometric measure to consistently explain differences in breast kinematics between cup sizes. Bare-breasted kinematics significantly increased with cup size during running. Differences in breast displacement, velocity, and acceleration between cup sizes could be predicted using estimates of breast mass based on conventional brassiere sizing. These data inform the design and evaluation of effective bra support.

Efficacy of different insole designs on fall prevention of the elderly

Purpose Between 28 to 35% of people aged over 65 fall in a year; for those aged over 70 the falling rate is as high as 32 to 42%. Many factors may lead to a fall, and these risk factors can be categorized as either endogenous or exogenous. Propriocepton biofeedback and ankle strategy are one of the basic control mechanism to keep posture balance and prevent falling. The purpose of this study was to evaluate different hardness and arch support designs in controlling the posture stability. Method A group of fifteen ‘fallers’, i.e fall-experienced elderly, (average age 67.7±2.4 years) and eighteen non-faller elderly (average age 68.7±3.1 years) were recruited for this study. The elderly were subjected to an exhaustive examination which included collecting demographic data, a proprioceptive test, a functional balance test, a Berg-balance test, as well as a dynamic balance assessment system tested with the eye open or closed (Biodex Medical System, Inc., USA) with a pressure mat (Xsensor X3, Canada) on top of the platform. Four types of orthotic insoles (Performace, Proactive, and Hardboot from Footdisc®, and Power step from Dr. Kong). The insoles each had different arch support hardness used to support ankle stability during ankle rocker motion, and cushions at metatarsal heel regions used to protect sensitive foot structure against strain and proprioception. During each test, foot pressure and the center of pressure (CoP) were recorded and analyzed. Statistical analysis was performance using SPSS v17.0 software. Results & Discussion The faller group showed significant larger CoP excursion particularly in the medial-lateral direction, as well as the anterior-posterior mean CoP velocity with the eye opened. In the test with eye closed, the CoP trajectory increased profoundly, although the faller group was larger than the non-fallers, but this was not significant. The increased of media-lateral (ML) sway implies an increased fall risk; poor vision elevated the falling rate. With orthotics, the sway trajectory reduced, among that the Proactive insole (arch height 1.75cm) showed the best posture stability control. It reduced the ML-excursion with an average of 29% for non-fallers and 35% for fallers, respectively.

Age Differences In Total And Regional Skeletal Muscle Mass, Posture Control And Physical Working Capacity

Aging is associated with a progressive decline of muscle mass, strength, bone mineral density (BMD) and quality, i.e., a condition described as sarcopenia from aging. The balance ability in elderly people depends on their muscular strength and physical working capacity. PURPOSE: The purpose of this study was to examine control of sit-to-stand, quiet standing, skeletal muscle mass and muscular strength in young and elderly people. METHODS: Healthy young (n=8, age 21.5±1.1yrs, height 169.1±6.4cm, body weight 60.3±6.7kg) and elderly (n=5, age 68.4±4.3yrs, height 162.2±5.7cm, body weight 63.2±7.4kg) male subjects participated in this study. The grip strength, flexibility (sitting trunk flexion), and knee extension muscular strength (30-second chair-stand test; CS-30) of all subjects were measured. The displacements of COP of ground reaction forces were recorded at a frequency of 20 Hz while the subjects were standing still on a force platform for 30 seconds, and the total length of COP displacements was calculated. The thickness of 9 muscles was measured by B-mode ultrasonograph to estimate the total for the whole body and regional skeletal muscle mass by the method of Sanada et al. (Eur J Appl Physiol, 96: 24-31, 2006). RESULTS: In comparison with the young subjects, the elderly subjects were significantly lower in predicted skeletal muscle mass of trunk (37%), thigh (19%), lower leg (22%) and the total for the whole body (24%), and CS-30 (38±4 vs. 16±2 times, p<0.001). However, there was no significant difference between the tow groups in arm skeletal muscle mass and BMD. A significant age difference did exist for the mean anterior-posterior (A/P) length of COP displacements (31.0±6.2 vs. 41.8±5.0 mm, p<0.01). There was a significant negative correlation between CS-30 and A/P length of COP displacements (r=-0.709, p<0.01). CONCLUSIONS: The results reconfirmed that muscle mass, leg strength, and the ability of balance control reduced in the natural aging process. The present study was suggested that the negative correlation between CS-30 and A/P length of COP displacements indicated a conservative enlargement of the muscle mass of the supporting limb by strength training. This conservative strategy may be related to the prevention of accidental fall that causes injury and death in the elderly people.

An Analysis of the Relationship between the Morphometry of the Distal Femur, and Total Knee Arthroplasty Implant Design

Current available implants for total knee replacement are based on the mormphometry of the Caucasian knee. We believe there are significant morphometric differences in the Asian knee that will be relevant in future implant designs. Sixty-nine consecutive patients (80 knees) underwent computer navigated primary total knee arthroplasty. The anterior-posterior (AP) length, and the medial-lateral (ML) width of the distal femur, were analyzed, with respect to the final sizing details of four implants (femoral component) commonly used locally. The mean AP length was 59.9 (SD 4.8) mm, and the mean ML width was 65.0 (SD 5.0) mm. The overall mean aspect ratio (ML/AP) was 1.09 (SD 0.07). The mean aspect ratio for females was 1.08 (SD 0.07). Both were smaller than the aspect ratio of the implants - which ranged from 1.11 to 1.13. All four implants tend to ‘overhang’ at the medial-lateral width of the distal femur. This is more obvious in females. Future implant designs should provide more ‘ML w›dth’ sizes for a given ‘AP length’, in addition to gender differences, for th›s population.

Implications of Respiratory Motion as Measured by Four-Dimensional Computed Tomography for Radiation Treatment Planning of Esophageal Cancer

To evaluate the respiratory motion of primary esophageal cancers and pathologic celiac-region lymph nodes using time-resolved four-dimensional computed tomography (4D CT). Respiration-synchronized 4D CT scans were obtained to quantify the motion of primary tumors located in the proximal, mid-, or distal thoracic esophagus, as well as any involved celiac-region lymph nodes. Respiratory motion was measured in the superior-inferior (SI), anterior-posterior (AP), and left-right (LR) directions and was analyzed for correlation with anatomic location. Recommended margin expansions were determined for both primary and nodal targets. Thirty patients underwent 4D CT scans at Massachusetts General Hospital for planned curative treatment of esophageal cancer. Measurements of respiratory tumor motion were obtained for 1 proximal, 4 mid-, and 25 distal esophageal tumors, as well as 12 involved celiac-region lymph nodes. The mean (SD) peak-to-peak displacements of all primary tumors in the SI, AP, and LR dimensions were 0.80 (0.45) cm, 0.28 (0.20) cm, and 0.22 (0.23) cm, respectively. Distal tumors were found to have significantly greater SI and AP motion than proximal or mid-esophageal tumors. The mean (SD) SI, AP, and LR peak-to-peak displacements of the celiac-region lymph nodes were 0.92 (0.56) cm, 0.46 (0.27) cm, and 0.19 (0.26) cm, respectively. Margins of 1.5 cm SI, 0.75 cm AP, and 0.75 cm LR would account for respiratory tumor motion of >95% of esophageal primary tumors in the dataset. All celiac-region lymph nodes would be adequately covered with SI, AP, and LR margins of 2.25 cm, 1.0 cm, and 0.75 cm, respectively.

Frontal plane knee angle affects dynamic postural control strategy during unilateral stance.

Center of plantar pressure (COPP) location moves toward the forefoot as ankle plantar flexor muscles attempt to maintain postural control during single leg stance. This study evaluated relationships between frontal plane tibiofemoral joint angulation during relaxed bilateral stance and mean COPP locations during vision-denied single leg stance at 20 degrees knee flexion. Fifty-six nonimpaired athletes (29 female, 27 male) were evaluated for frontal plane tibiofemoral joint angulation and standing foot angle by using two-dimensional videography (30 Hz). Mean anterior-posterior and mediolateral COPP locations were assessed during single leg stance on a mat (25 Hz, 15 s). One-way ANOVA and Tukey HSD tests evaluated group differences (P < or = 0.05) based on frontal plane tibiofemoral joint angulation. Group 1 (genu varus or genu valgus < 5 degrees ) displayed a mean anterior-posterior COPP location of 54.2 +/- 6% from the (0,0) coordinate starting point at the anterolateral foot (10.3 +/- 2 cm from the posterior sensor edge). Group 2 (genu varus angulation > or = 5 degrees ) and group 3 subjects (genu valgus angulation > or = 5 degrees ) displayed mean anterior-posterior COPP locations of 60.6 +/- 8% and 60.7 +/- 7% (8.8 +/- 2 cm and 8.7 +/- 2 cm from the posterior sensor edges), respectively. Group 2 (12.5 +/- 3 N x kg(-1)) and group 3 (12.4 +/- 3.1 N x kg(-1)) subjects also displayed greater mean plantar force magnitude/body weight than group 1 (10.3 +/- 2 N x kg(-1)) subjects. Mean ankle plantar flexor moment magnitudes did not differ between groups. Rearfoot directed mean anterior-posterior COPP locations and greater plantar force magnitudes/body weight suggests that subjects with genu varus or genu valgus relied more on the subtalar and midtarsal joint control function of the ankle plantar flexor muscle group for lower extremity dynamic postural control.

Striking findings concerning the variability in the measurement of the fetal renal collecting system.

Using strict thresholds of normality, investigators have reported associations between fetal pyelectasis and aneuploidy, obstructive uropathy, postnatal pyeloplasty and vesicoureteral reflux. Although evidence continues to mount regarding the importance of fetal pyelectasis, little is known of the variability of collecting system measurements. To investigate the short-term variability and its relationship to bladder dilatation, the following study was conducted. During May and June 1996, 20 mid- and late-trimester patients with varying degrees of fetal pyelectasis were recruited into this study. Each consented to undergo periodic (every 15 min for 2 h) ultrasound measurements of the fetal renal collecting systems and bladder. To account for anatomic and technical variability in measurement, we used both the sum of the transverse and anterior-posterior (AP) measurements of the collecting systems, and AP measurement alone for comparison. The variability of the collecting system measurements was assessed based upon gestational age, magnitude of pyelectasis and fetal bladder size. We investigated 38 renal units in 20 patients (eight in the second trimester and 12 in the third). The mean(SE) AP diameter of all kidneys was 5.89(2.49) mm (range 15 (2-17) mm), and the sum of transverse and AP renal collecting system diameters was 13.91(5.73) mm (range 26 (4-31) mm). These data were normally distributed. When assessing the variability in individual kidneys over time, we found the mean variation (minimum to maximum) for the sum of the AP and transverse measurement to be 7.61(4.26) mm and for the AP measurement alone to be 3.80(2.49) mm. No relationship was found between variability of dilatation, magnitude of dilatation or fetal bladder size. Cyclic dilatation of the fetal bladder was observed in all cases. The mean time from maximal to minimal dilatation was 20 min (1.34 observations; range 12-30 min). We found the size of the fetal renal collecting system to be highly variable over the course of a 2-h period. Seventy per cent of cases (14 of 20) had both normal (< 4 mm) and abnormal values (> or = 4 mm) during the 2-h study period. Significant caution should be used when considering the implications of renal collecting system dilatation based upon a single AP measurement.