The Relationship Between Quadriceps Femoris Muscle Function and MRI-Derived Water Diffusion and Adipose Tissue Measurements in Young Healthy Males.

BACKGROUND: Water diffusion and adipose tissue in a muscle can be evaluated by MRI. However, determining which quadriceps femoris muscle (QM) characteristics independently predict peak knee extension torque during maximum voluntary isometric contractions (MVICs), individual muscle activity during MVICs and sit-to-stand transitions is unknown. PURPOSE: To determine which QM characteristics predict knee extension muscle strength and individual muscle activity. STUDY TYPE: Prospective, cross-sectional. SUBJECTS: A total of 20 healthy males (aged 22-40 years) with a physical activity level <1 hour/week. FIELD STRENGTH/SEQUENCE: 1.5-T, diffusion-weighted fast spin-echo echo-planar imaging and T1-weighted fast spin-echo sequences. ASSESSMENT: The vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), and vastus intermedius were segmented in a single axial diffusion-weighted image and T1-weighted image at the right mid-thigh region. λ1-3 and fractional anisotropy (FA), and the percentage of intramuscular adipose tissue (IMAT) were measured. The knee extension peak force during MVICs was measured by a dynamometer, and the torque was calculated at the peak force × length. The ratios of the individual muscle activity to the total muscle (VM, VL, and RF) during MVICs and sit-to-stand transitions were assessed using surface electromyography. STATISTICAL TESTS: Regression analysis was conducted to identify the predictors of peak knee extension torque and of individual muscle activity ratios. A P value < 0.05 was considered statistically significant. RESULTS: The RF λ1 significantly predicted the peak knee extension torque (ß = -0.51). The IMAT percentage of the VM significantly predicted the VM muscle activity ratio during the MVIC and sit-to-stand transition (ß = -0.82 and ß = -0.61, respectively), whereas the ratio of the VM λ1 to the whole QM λ1 significantly predicted the VM muscle activity ratio during the sit-to-stand transitions (ß = 0.35 and ß = 0.46, respectively). DATA CONCLUSION: The RF λ1 may allow to estimate peak knee extension muscle torque, and the VM IMAT and λ1 may predict muscle activity in youth. EVIDENCE LEVEL: 3. TECHNICAL EFFICACY: Stage 3.

Knee alignment and individual quadriceps femoris muscle thicknesses and their relationships with postnatal motor development and subcutaneous fat thickness: A cross-sectional study in Japanese infants.

BACKGROUND: Postnatal changes in individual quadriceps femoris muscle thicknesses and the relationships between knee alignment and quadriceps thicknesses, postnatal motor development, and subcutaneous fat thickness are unclear. This study investigated knee alignment and individual quadriceps thickness ratios in Japanese infants and investigated their relationships with postnatal motor development and subcutaneous fat thickness. METHODS: One-year-old (n = 28), 2-year-old (n = 26), and 3-year-old infants (n = 22) were included. Postnatal months when the infants began crawling, standing, and walking were assessed. The intercondylar distance was measured, and the individual quadriceps and subcutaneous fat thicknesses at the right mid-thigh were measured using ultrasonography. The individual quadriceps:total quadriceps muscle thickness ratios were calculated. Analysis of variance tests in the 3 groups were conducted for the intercondylar distances and individual quadriceps thickness ratios, and correlation coefficients between the parameters were evaluated in each group. FINDINGS: Intercondylar distance was longer in 1-year-old infants than in 2-year-old infants (p < 0.001), without significant differences between 2-year-old and 3-year-old infants (p = 0.33). The rectus femoris thickness ratio was higher in 1-year-old infants than in 3-year-old infants (p = 0.013), whereas the vastus medialis thickness ratio was higher in 3-year-old infants than in 2-year-old infants (p = 0.024). In 3-year-old infants, a larger subcutaneous fat thickness, but not postnatal motor development, was correlated with a longer intercondylar distance and a lower vastus medialis thickness ratio (rs = 0.53, p = 0.012; rs = -0.46, p = 0.032, respectively). INTERPRETATION: Further studies on the relationships between subcutaneous fat and knee alignment and vastus medialis in juveniles, adolescents, young adults, and elderly people are expected.

The influence of knee varus and valgus on quadriceps muscle activity changes induced by stretching and kneeling.

This study aimed to determine the influence of knee varus (VARUS) and valgus (VALGUS) on the differences in individual quadriceps muscle (QM) activity during knee extension maximum voluntary isometric contractions (MVICs) and sit/stand transitions and on the changes in individual QM activity during sit/stand transitions after QM stretching and kneeling. Ten young healthy males each with VARUS and VALGUS were included. The electromyography signals of the vastus medialis (VM), vastus lateralis, and rectus femoris were recorded during sit/stand transitions before and after rest, stretching, and kneeling and during knee extension MVICs after rest. The individual muscle-to-total muscle activity ratio was assessed. The VARUS group exhibited a significantly higher VM muscle activity ratio in the sit-to-stand and stand-to-sit tasks than in knee extension MVICs (p = 0.004 and p = 0.044, respectively) and a tendency that the VM muscle activity ratio increased in the sit-to-stand task after stretching (p = 0.051), whereas the VALGUS group exhibited no significance. Individuals with VARUS required high VM muscle activity ratios during sit/stand transitions. Future studies should be conducted to determine whether habitual sit-to-stand exercises after QM stretching are effective in preventing knee medial osteoarthritis development in individuals with VARUS.

A risk factor associated with subsequent new vertebral compression fracture after conservative therapy for patients with vertebral compression fracture: a retrospective observational study.

Lumbar BMD and functional recovery in the acute period were independently strongly associated with subsequent new VCF after hospital conservative therapy for patients with new fragility VCFs. Functional recovery was related with age, pain intensity during first month after hospitalization, VCF past history and multiple new VCFs. PURPOSE: This study aimed to determine the factors independently associated with the subsequent vertebral compression fracture (VCF) after hospital conservative therapy in patients with new fragility VCFs and parameters related with functional recovery in the acute period. METHODS: Subsequent VCF (n = 37) was defined as patients who sustained a new VCF within 9 months after new VCF, whereas patients without a new VCF were classified as non-subsequent VCF (n = 179). Logistic regression analysis was performed to determine independent factors associated with the subsequent VCF, including patients' characteristics, past histories, number of new VCFs, bone mineral density (BMD), lumbar sagittal alignment, fractured vertebral body height, spine muscle mass, pain intensity, corset types, medications for osteoporosis and pain relief, recovery ratio of functional independence measure (FIM) and bone union. Correlation coefficients were accessed between the FIM recovery ratio and continuous variable parameters, while intergroup comparisons or analysis of variance was conducted to examine significant differences in the FIM recovery ratio for categorical variable parameters. RESULTS: Lumbar BMD, FIM recovery ratio at the first month after hospitalization and segmental Cobb angle were significantly independently associated with subsequent VCF (odds ratio: 27.8, 9.6 and 1.1, respectively). The FIM recovery ratio was moderately negatively correlated with age and pain intensity and was significantly worse in patients with multiple new VCFs or past history of VCF. CONCLUSIONS: Conservative therapies focused on lumbar BMD, functional recovery and pain relief in the acute period may be useful in preventing subsequent VCF.

Atrophy of individual thigh muscles measured by MRI in older adults with knee osteoarthritis: A cross-sectional study.

BACKGROUND: The characteristics of thigh-muscle cross-sectional area (CSA) in older adults with knee osteoarthritis (KOA) remain controversial. OBJECTIVES: This study aimed to evaluate atrophy of individual thigh muscles in older adults with KOA and to determine which muscle CSA should be measured to detect KOA-related muscle atrophy of the thigh. METHODS: In older adults, individual thigh-muscle CSA measured by 1.5 Tesla MRI was analyzed at 5% intervals of the femoral length (FL) around the mid-thigh between the proximal 25% of the FL and the distal 25%. Participants with KOA grade≤1 and grade≥2 were compared for ratios of quadriceps muscle (QM) CSA to total thigh, individual QM CSA to QM, and individual hamstring (HAM) CSA to HAM at 5% intervals. RESULTS: We included 40 older adults [20 males; mean (SD) age 73.3 (4.7) years; 20 with KOA grade≤1 and 20 with KOA grade≥2]. The ratio of vastus medialis (VM) CSA to QM from the proximal 25% to distal 15% and the ratio of semi-membranosus (SM) CSA to HAM at the distal 10% to 25% were significantly lower with KOA grade≥2 than grade≤1; the effect sizes were 0.34 to 0.67 for VM and 0.40 to 0.60 for SM. The effect sizes were greatest for the ratios of VM CSA to QM at the mid-thigh with 5% intervals and the ratio of SM CSA to HAM at the distal 25%. CONCLUSIONS: The ratio of VM CSA to QM and/or that of SM CSA to HAM were low and were the best indicators to detect KOA-related muscle atrophy of the thigh. However, to detect KOA-related muscle atrophy, the VM CSA ratio should be analyzed in the thigh region around the mid-thigh, whereas the SM CSA ratio should be analyzed in the thigh region at the muscle belly.

Characteristics of individual thigh muscles including cross-sectional area and adipose tissue content measured by magnetic resonance imaging in knee osteoarthritis: a cross-sectional study.

This study aimed to identify the parameters related to the area and adipose tissue content of thigh muscles that are associated with radiographic knee osteoarthritis grade. Fifty patients (mean age ± standard deviation, 73.0 ± 4.5 years) were divided into early osteoarthritis (n = 23) and established osteoarthritis (n = 27) groups based on Kellgren-Lawrence classification. The femorotibial angle was measured from anteroposterior radiographs of the lower limbs. Individual thigh muscle and adipose tissue areas were analyzed using axial T1-weighted magnetic resonance imaging. After intergroup comparison, logistic regression analysis was performed to determine independent parameters associated with established osteoarthritis. Moreover, correlation coefficients were assessed between the left-right differences of osteoarthritis grade and parameters. Established osteoarthritis exhibited a significantly greater femorotibial angle and increased adipose tissue content in the subcutaneous, intermuscle, and intramuscle of the adductor, vastus lateralis, vastus intermedius, as well as a lower vastus medialis area, in comparison to early osteoarthritis. A greater femorotibial angle, increased intermuscular adipose tissue, and a lower vastus medialis area to knee extensor ratio were significantly independently associated with established osteoarthritis (odds ratio 3.2, 1.8, and 2.0, respectively). The left-right differences of femorotibial angle and vastus medialis area were significantly correlated with osteoarthritis grade, whereas adipose tissue content had no significant correlations with osteoarthritis grade. Greater femorotibial angle and lower vastus medialis area were related with higher osteoarthritis grade. Greater intermuscular adipose tissue content was associated with established osteoarthritis; however, in the left-right differences, adipose tissue content was not related with osteoarthritis grade.

Effects of post-fracture non-weight-bearing immobilization on muscle atrophy, intramuscular and intermuscular adipose tissues in the thigh and calf.

OBJECTIVE: Disuse and/or a non-weight-bearing condition changes muscle composition, with decreased skeletal muscle tissue and increased fat within (intramuscular adipose tissue, IntraMAT) and between (intermuscular adipose tissue, InterMAT) given muscles. Excessive adipose tissue contributes to dysfunctional and metabolically impaired muscle. How these adipose tissues change during orthopedic treatment (e.g., cast immobilization, daily use of crutches) is not well documented. This study aimed to quantify changes in IntraMAT, InterMAT, and thigh and calf muscle tissue during orthopedic treatment. MATERIALS AND METHODS: We studied 8 patients with fifth metatarsal bone or fibular fractures. The ankle joint involved underwent plaster casting for approximately 4 weeks, with crutches used during that time. Axial T1-weighted MRI at the mid-thigh and a 30% proximal site at the calf were obtained to measure IntraMAT and InterMAT cross-sectional areas (CSAs) and skeletal muscle tissue CSA before treatment and 4 weeks afterward. RESULTS: Thigh and calf muscle tissue CSAs were significantly decreased from before to after treatment: thigh, 85.8 ± 7.6 to 77.1 ± 7.3 cm2; calf, 53.3 ± 5.5 to 48.9 ± 5.0 cm2 (p < 0.05). None of the IntraMAT or InterMAT changes was statistically significant. There was a relation between the percentage change of thigh IntraMAT CSA and muscle tissue CSA (rs = -0.86, p < 0.01). CONCLUSIONS: The 4 weeks of treatment primarily induced skeletal muscle atrophy with less of an effect on IntraMAT or InterMAT. There is a risk of increasing IntraMAT relatively by decreasing skeletal muscle tissue size during orthopedic treatment.

Estimation of individual thigh muscle volumes from a single-slice muscle cross-sectional area and muscle thickness using magnetic resonance imaging in patients with knee osteoarthritis.

PURPOSE: This study aimed to identify the best single-slice anatomical muscle cross-sectional area (CSA) and muscle thickness (MT) on magnetic resonance imaging (MRI) to estimate the overall individual muscle volumes (MVs) of knee extensors and flexors in patients with knee osteoarthritis (KOA). METHODS: Twelve patients (24 legs; 4 men and 8 women) with KOA underwent a 1.5-Tesla axial MRI scan in the femoral region of interest (ROI), between the lesser trochanter and rectus femoris tendon. Individual MVs were calculated by numerical integration based on individual CSAs analyzed at the ROI. The best slice was determined as follows: coefficient of determination ( R2) between MVs measured and those estimated from the femoral length (FL) × CSAs or FL × MTs measured at each 10% interval level of the ROI. These estimation equations were applied for a cross-validation group (24 KOA patients: 12 men and 12 women). RESULTS: Estimated individual MVs of knee extensors and flexors, based on the CSAs at the distal 10% level, significantly correlated with each of the measured individual MVs ( R2: 0.79-0.96, p < 0.05 for all). Similarly, estimated individual knee extensor MVs, based on MTs at the mid-slice, significantly correlated with each of the measured individual MVs ( R2: 0.77-0.84, p < 0.05 for all). The application of the developed regression equation to the cross-validation group did not exhibit any systematic bias. CONCLUSION: These simple methods could be applied in prospective research with a larger number of patients with KOA.

Sagittal Alignment of a Strut Graft Affects Graft Subsidence and Clinical Outcomes of Anterior Cervical Corpectomy and Fusion.

STUDY DESIGN: Retrospective study. PURPOSE: The purpose of this study was to investigate the influence of sagittal alignment of the strut graft on graft subsidence and clinical outcomes after anterior cervical corpectomy and fusion (ACCF). OVERVIEW OF LITERATURE: ACCF is a common technique for the treatment of various cervical pathologies. Although graft subsidence sometimes occurs after ACCF, it is one cause for poor clinical results. Malalignment of the strut graft is probably one of the factors associated with graft subsidence. However, to the best of our knowledge, no prior reports have demonstrated correlations between the alignment of the strut graft and clinical outcomes. METHODS: We evaluated 56 patients (33 men and 23 women; mean age, 59 years; range, 33-84 years; 45 with cervical spondylotic myelopathy and 11 with ossification of the posterior longitudinal ligament) who underwent one- or two-level ACCF with an autogenous fibular strut graft and anterior plating. The Japanese Orthopaedic Association (JOA) score recovery ratio for cervical spondylotic myelopathy was used to evaluate clinical outcomes. The JOA score and lateral radiograms were evaluated 1 week and 1 year postoperatively. Patients were divided into two groups (a straight group [group I] and an oblique group [group Z]) based on radiographic assessment of the sagittal alignment of the strut graft. RESULTS: Group I showed a significantly greater JOA score recovery ratio (p<0.05) and a significantly lower graft subsidence than group Z (p<0.01). CONCLUSIONS: Our findings suggest that a straight alignment of the strut graft provides better clinical outcomes and lower incidence of graft subsidence after ACCF. In contrast, an oblique strut graft can lead to significantly increased strut graft subsidence and poor clinical results.

Muscle atrophy and recovery of individual thigh muscles as measured by magnetic resonance imaging scan during treatment with cast for ankle or foot fracture.

PURPOSE: We aimed to longitudinally investigate individual thigh muscle changes using magnetic resonance imaging (MRI) during treatment with cast of ankle or foot fracture. Moreover, we aimed to demonstrate whether measurements of muscle cross-sectional area (CSA) are sensitive to muscle changes, contributing to simpler methods in clinical application . METHODS: Ten patients undergoing treatment with cast of acute ankle or foot fractures were studied. Axial MRI (1.5 T) was conducted around the affected mid-thigh region after the injury (Pre), after maintaining a nonweight-bearing (NWB) period (approximately 28 days), and after finishing rehabilitation (recovery). Regarding individual thigh muscles, the total CSAs corresponding to 40% of the femoral length (FL) and the CSAs at 5% interval of the FL were longitudinally measured. Standardized response means (SRMs) were accessed for sensitivity in the muscle changes. RESULTS: The total CSAs at NWB were significantly lower than those at Pre in vastus lateralis (10.9% ± 5.4%), vastus intermedius (8.4% ± 6.7%), and vastus medialis (11.2% ± 6.9%) ( p < 0.01 for all). In contrast, at recovery, the only significant muscle atrophy relative to that at Pre was observed in the semitendinosus of the proximal 15% and 10% CSAs ( p < 0.01 and p = 0.01, respectively). In all muscles, SRM using a single-slice CSA at or near the muscle belly was high. CONCLUSION: Thigh muscle changes differ according to the variations in individual muscles. CSA measurements at or near the muscle belly are simple methods and sensitive indicators of these muscle changes.

Comparison of morphological features in the femur between femoral neck fractures and femoral intertrochanteric fractures.

PURPOSE: The purpose of this study is to make proximal femur fracture types more predictable by considering morphological features of an acetabulum as well as of a proximal femur in the Japanese population. METHODS: A retrospective review of radiographs of the proximal femoral fractures was conducted in patients registered from 2010 to 2012, dividing into patients with femoral neck fractures; Group Neck (n = 101), and patients with femoral intertrochanteric fractures; Group IT (n = 99). Intergroup comparison was conducted: age, sex, height, weight, the ratios of femoral intertrochanteric length (IT Length), femoral neck length (Neck Length), femoral neck width (Neck Width), lateral offset length (Offset) to femoral head diameter, neck-shaft angle (N-S angle), and center-edge angle of the acetabulum (C-E angle), adjusting for age. Multiple logistic regression analysis was conducted among these parameters. RESULTS: The Group IT showed significantly older age than the Group Neck. Greater C-E angle in Group IT was observed in the patients in their 80s and 90s years of age. The Group Neck showed greater N-S angle only in the patients in their 80s years of age. In multiple logistic regression analysis, the impact of the age and the C-E angle on the fracture types was similar (odds ratio 1.08, 1.09, respectively, p < 0.01 both). CONCLUSIONS: Age, N-S angle, and C-E angle could be independent predictors for determining the proximal femur fracture types.

Comparison of functional recovery in the very early period after surgery between plate and nail fixation for correction of stable femoral intertrochanteric fractures: a controlled clinical trial of 18 patients.

PURPOSE: This study aimed to compare the differences in functional recovery between patients undergoing plate and nail fixation in the very early period after surgery. METHOD: This study was designed as a controlled clinical trial that included 18 patients who were surgically treated with either dynamic hip screw as plate fixation or proximal femoral nail as nail fixation for stable intertrochanteric fractures. In particular, all patients selected for the study reported walking completely independently without the use of walking aids prior to sustaining their initial fracture. In all, 8 patients (mean age, 73.8 years; range, 65-89 years) were treated with plate fixation (group plate) and 10 patients (mean age, 79.7 years; range, 70-90 years) were treated with nail fixation (group nail). Functional evaluations were assessed every week after surgery using the Japanese Orthopaedic Association (JOA) hip functional scores and active range of motion (ROM) of the hip joint. RESULTS: The recovery of activities of daily living (ADLs) according to JOA hip functional scores at week 4 after surgery was significantly better in group nail than in group plate (P = .03), whereas active ROM of hip flexion improved significantly in group plate than in group nail at weeks 3 and 4 after surgery (P = .04 and P = .02, respectively). CONCLUSIONS: The results suggested that nail fixation may provide a more rapid recovery of ADLs than that of plate fixation in the very early period after surgery. However, plate fixation may provide better ROM of hip flexion than that of nail fixation.

Fatal fat embolism syndrome in a case of isolated L1 vertebral fracture-dislocation.

Although fat embolism syndrome is a well-known complication of fractures of the long bones or pelvis, fat embolism syndrome occurring subsequent to fracture of the lumbar spine is rare. We report a fatal case of fat embolism syndrome characterized by fat and bone marrow embolism that occurred 36 h after an isolated fracture-dislocation of the L1 vertebra. A postmortem examination was performed and pathological finding demonstrated fat and bone marrow tissue which were disseminated in the bilateral pulmonary arteries. We need to be aware of the possibility of fat embolism syndrome as a complication of spinal fractures, including isolated vertebral body fractures.

The relationship between intestinal histology and function as shown by compensatory enlargement of remnant villi after midgut resection in chickens.

To demonstrate the relationship between intestinal histology and function, we investigated the possibility that compensatory enlargement of villi in the chickens' remnant intestine can be induced after 50% or 80% jejunal resection as well as after 50% jejunal plus 70% ileal resection. Compared with intact control chickens, operated chickens showed an almost similar body weight, nitrogen retention, and ether extract digestibility, an improved dry matter digestibility, and a much greater absorption of protein and ether extract by the remnant jejunum and ileum. This suggests an enhanced absorptive function of the remnant intestine. In these chickens, increased value of most light microscopic parameters, increased frequency of anastomosing of each villus, and increased number of protuberated epithelial cells appeared with an increase in the intestinal resection area. This suggests that intestinal villi and epithelial cells are hypertrophied in the remnant jejunum and ileum, and that intestinal villi adapt to activated intestinal absorptive function not by increasing their numbers, but by fusing together into larger villi. These findings demonstrate that intestinal histology is intimately related to intestinal function.

Characteristics of upper extremity injuries sustained by falling during snowboarding: a study of 1918 cases.

BACKGROUND: Little epidemiological research on characteristics of upper extremity injuries resulting from snowboarding has been conducted, particularly in relation to snowboarding stance, falling direction, and the side of the body where the injury occurs. HYPOTHESIS: Snowboarding stance and the direction of the fall may influence the frequency of the side or the location of the upper extremity injury. STUDY DESIGN: Descriptive epidemiology study. METHODS: This study analyzed the information obtained from 1918 patients with fractures or dislocations of the upper extremity (excluding the fingers and scapula) sustained during snowboarding/sliding between 2000 and 2008. Diagnosis, injured part and side, stance (regular or goofy), and falling directions were prospectively analyzed. Associations among these parameters were also analyzed. RESULTS: As characterized by skill level, patients were beginners (57.9%), intermediates (38.0%), and experts (4.0%). Eighty-eight percent had not received instruction from licensed instructors. Diagnoses included wrist fractures (53.7%), upper arm fractures (16.8%), shoulder dislocations (11.5%), and elbow dislocations (9.8%). In sum, 1742 (90.8%) patients were in regular stance when they fell, whereas 176 (9.2%) were in goofy stance. There was a significant difference in the prevalence of the injured side between the 2 stances. When the injured sides were classified according to the sliding direction, wrist fractures (61.7%) occurred on the side opposite the sliding direction, whereas shoulder dislocations (65.6%), upper arm fractures (82.9%), and elbow dislocations (79.8%) occurred on the same side as the sliding direction. When the injured sides were classified according to the falling direction, wrist fractures (68.1%) and elbow dislocations (63.5%) occurred because of backward falls, and shoulder dislocations (68.9%) and upper arm fractures (60.7%) occurred because of forward falls. CONCLUSION: Two snowboarding stances as well as 2 falling directions had a significant influence on the frequency of the injured side in the upper extremity.