Alterations in cartilage quantification before and after injections of mesenchymal stem cells into osteoarthritic knees.

Several studies have reported improvement in knee pain following mesenchymal stem cell (MSC) injections for knee osteoarthritis (OA). We developed a novel 3D magnetic resonance imaging (MRI) analysis software program that provides "projected cartilage area ratios" for automatic detection of changes in cartilage amounts. The primary objective of this prospective interventional study was to compare alterations in the projected cartilage area ratio (thickness ≥ 1.5 mm) at the femoral posteromedial region between 30 weeks before and 30 weeks after synovial MSC injections. Secondary objectives were to assess the clinical scores and safety of MSC injections. Patients with OA who complained of knee pain underwent autologous synovial MSC injections into the knee at time 0 and again 15 weeks later. MRI examinations were performed at - 30, - 15, - 1, and 30 weeks. Patients showing < 3% decreases in the projected cartilage area ratio (thickness ≥ 1.5 mm) at the femoral the posteromedial region from - 30 weeks to - 15 weeks were excluded from the study. The Lysholm Knee Score, Knee Injury and Osteoarthritis Outcome Scale (KOOS), and Numerical Rating Scale (NRS) scores were evaluated at - 30, - 15, - 5, - 2, 0, 5, 10, 15, 20, 25, and 30 weeks. Five patients were excluded because 3D MRI analysis showed no cartilage loss at - 15 weeks. Ultimately, eight OA patients underwent MSC injections. The projected cartilage area ratio significantly decreased by 0.07 in the 30 weeks before MSC injections (p = 0.01), but no further decreases occurred in the 30 weeks after MSC injections. The projected cartilage area ratio at the femoral posteromedial region showed a significant difference between 30 weeks before and 30 weeks after MSC injections. The Lysholm Knee Score, KOOS, and NRS values improved significantly after the injections. MSC injection could not be ruled out as the cause of two adverse events: transient knee pain and itching in both hands. Fully automatic 3D MRI analysis showed that synovial MSC injections suppressed cartilage loss in patients with progressive OA.Trial registration: Intraarticular injections of synovial stem cells for osteoarthritis of the knee (Number UMIN 000026732). Date of registration; June 1, 2017. https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000029967 .

Systematic Isolation of Key Parameters for Estimating Skeletal Maturity on Knee Radiographs.

BACKGROUND: The ability to estimate skeletal maturity using a knee radiograph would be useful in anterior cruciate ligament (ACL) injuries and limb-length discrepancy in immature patients. Currently, a quick, accurate, and reproducible method is lacking. METHODS: Serial knee radiographs made 3 years before to 2 years following the chronologic age associated with 90% of final height (an enhanced skeletal maturity gold standard compared with peak height velocity) were analyzed in 78 children. The Pyle and Hoerr (PH) knee method was simplified by developing discrete stages for the distal part of the femur, the proximal part of the tibia, the proximal part of the fibula, and the patella. The Roche-Wainer-Thissen (RWT) knee method was simplified from the 36 original parameters to 14 parameters by removing parameters that were poorly defined, were not relevant to the peripubertal age range, were poorly correlated with 90% final height, or were poorly reliable on a 20-radiograph pilot analysis. We also compared the recently described central peak value (CPV) of the distal part of the femur. The Greulich and Pyle (GP) left-hand bone age was included for comparison. RESULTS: In this study, 326 left knee radiographs from 41 girls (age range, 7 to 15 years) and 37 boys (age range, 9 to 17 years) were included. Stepwise linear regression showed higher correlation in predicting years from 90% final height using the modified RWT and demographic characteristics (R2 = 0.921) compared with demographic characteristics alone (R2 = 0.840), CPV and demographic characteristics (R2 = 0.866), GP and demographic characteristics (R2 = 0.899), and PH and demographic characteristics (R2 = 0.902). Seven parameters were excluded from the RWT and demographic characteristics model using stepwise linear regression and generalized estimating equations analysis, leaving 7 parameters (2 femoral, 4 tibial, and 1 fibular) in the final model. Compared with RWT and demographic characteristics (R2 = 0.921), there were minimal incremental increases by adding CPV (R2 = 0.921), GP (R2 = 0.925), or PH (R2 = 0.931). CONCLUSIONS: This large analysis of knee skeletal maturity systems isolated 7 discrete radiographic knee parameters that theoretically outperform the GP bone age in estimating skeletal maturity. CLINICAL RELEVANCE: We present a modified knee skeletal maturity system that can potentially preclude the need for additional imaging of the hand and wrist in reliably estimating skeletal maturity.

Automated age estimation of young individuals based on 3D knee MRI using deep learning.

Age estimation is a crucial element of forensic medicine to assess the chronological age of living individuals without or lacking valid legal documentation. Methods used in practice are labor-intensive, subjective, and frequently comprise radiation exposure. Recently, also non-invasive methods using magnetic resonance imaging (MRI) have evaluated and confirmed a correlation between growth plate ossification in long bones and the chronological age of young subjects. However, automated and user-independent approaches are required to perform reliable assessments on large datasets. The aim of this study was to develop a fully automated and computer-based method for age estimation based on 3D knee MRIs using machine learning. The proposed solution is based on three parts: image-preprocessing, bone segmentation, and age estimation. A total of 185 coronal and 404 sagittal MR volumes from Caucasian male subjects in the age range of 13 and 21 years were available. The best result of the fivefold cross-validation was a mean absolute error of 0.67 ± 0.49 years in age regression and an accuracy of 90.9%, a sensitivity of 88.6%, and a specificity of 94.2% in classification (18-year age limit) using a combination of convolutional neural networks and tree-based machine learning algorithms. The potential of deep learning for age estimation is reflected in the results and can be further improved if it is trained on even larger and more diverse datasets.

Overexpressing Runx2 of BMSCs Improves the Repairment of knee Cartilage Defects.

BACKGROUND: Recruitment of gene modifying bone marrow mesenchymal stem cells (BMSCs) has been considered an alternative to single-cell injection in articular cartilage repair. PURPOSE: This study aimed to investigate whether the effect of runt-related transcription factor 2(Runx2) overexpression bone marrow mesenchymal stem cells in vivo could improve the quality of repaired tissue of a knee cartilage defect in a rabbit model. METHODS: Thirty-two New Zealand rabbits were randomly divided into four groups. The blank group (Con) did not receive anything, the model group (Mo) was administered saline, the simple stem cell group (MSCs) received MSCs injection, and the Runx2 transfection group (R-MSCs) received Runx2 overexpression MSCs injection. After adapting to the environment for a week, a 5 mm diameter cylindrical osteochondral defect was created in the center of the medial femoral condyle. Cell and saline injections were performed in the first and third weeks after surgery. The cartilage repair was evaluated by macroscopically and microscopically at 4 and 8 weeks. RESULTS: Macroscopically, defects were filled and surfaces were smoother in the MSCs groups than in the Mo group at 4th week. Microscopically, the R-MSCs group showed coloration similar to surrounding normal articular cartilage tissue at 8 weeks in masson trichrome staining. The COL-II, SOX9, and Aggrecan mRNA expressions of MSCs were enhanced at 4 weeks compared with R-MSCs, then the expression reduced at 8 weeks, but was still higher than Mo group level (P<0.05). The western blot examination revealed that the COL-IIand SOX9 expression of MSCs was higher than R-MSCs at 4 weeks, then the expression reduced at 8 weeks, but was still higher than the Mo level (P<0.05). The IL-1ß content in the joint fluid also revealed that cartilage repair with R-MSCs was better than that with MSCs at 8 weeks (P<0.05). CONCLUSION: The R-MSCs group showed cellular morphology and arrangement similar to surrounding normal articular cartilage tissue, and Runx2 overexpression of MSCs resulted in overall superior cartilage repair as compared with MSCs at 8 weeks.

Attenuated activation of knee extensor muscles during fast contractions in older men and women.

AIM: Reduced physical function and increased risk of falls in older adults are accompanied by age-related reductions in torque development of leg muscles, although the mechanisms and potential sex differences are not understood. PURPOSE: To determine the mechanistic origins (neural vs. muscular) for the age-related reduction in torque development, we compared the peak rates of torque development (RTD) during electrically-evoked and fast voluntary contractions of the knee extensors between young and older men and women. METHODS: Sets of single- and double-pulse electrical stimulations evoked contractions of the knee extensor muscles in 20 young (23.0 ± 0.8 years; 10 women) and 20 older adults (78.2 ± 1.5 years; 10 women), followed by voluntary isometric knee extension contractions with torque development as fast as possible that matched the torque during electrically-evoked contraction (10-40% maximal torque). RESULTS: Peak RTD during fast-voluntary contractions was 41% less than electrically-evoked contractions (p < 0.001), but more so for older adults (44%) than young (38%, p = 0.04), with no sex differences. Peak RTD during fast-voluntary contractions was more variable between contractions for the older than young adults (77%MVC s-1 vs. 47%MVC s-1, p < 0.001). Additionally, older women exhibited greater variability than older men (81%MVC s-1 vs. 72%MVC s-1, p = 0.04) with no sex-related differences within the young adults. CONCLUSION: Older adults had slower and more variable RTD during voluntary contractions than young adults, particularly older women. The limited age-related differences in electrically-evoked RTD suggest the primary mechanism for the slower torque development of the knee extensor muscles in older men and women involve reduced neural activation.

Local knee heating increases spinal and supraspinal excitability and enhances plantar flexion and dorsiflexion torque production of the ankle in older adults.

PURPOSE: Aging is associated with progressive loss of active muscle mass and consequent decreases in resting metabolic rate and body temperature, and slowing of nerve conduction velocities and muscle contractility. These effectors compromise the ability of the elderly to maintain an upright posture during sudden balance perturbation, increase the risk of falls, and lead to self-imposed reduction in physical activity. Short-term superficial acute heating can modulate the neural drive transmission to exercising muscles without any marked change in deep-muscle temperature. METHODS: To determine whether the short-term (5 min) application of local passive knee-surface heating (next-to-skin temperature, ~ 44 °C) in healthy older subjects of both sexes (64-74 years; eight men/eight women) enhances reflex excitability, we compared the voluntarily and electrically induced ankle muscle torque production and contractile properties with those of healthy younger subjects of both sexes (21-35 years, 10 men/10 women). RESULTS: The application of local heating (vs. control) increased the maximal Hoffman reflex (Hmax), the maximal volitional wave (Vsup) amplitude, and the Hmax/Mmax amplitude ratio, and decreased Vsup latency only in older adults. In the older adults (vs. younger adults), the application of local heating (vs. control trial) was accompanied by a significant increase in maximal voluntary peak torque, rate of torque development, and isokinetic peak torque of plantar flexion/dorsiflexion muscle contraction. CONCLUSION: The spinal and supraspinal reflex excitability of older adults increased during local knee-heating application. The improved motor drive transmission observed in older adults was accompanied by increased voluntarily induced torque production of the ankle muscles during isometric/isokinetic contractions.

Radiographic/MR Imaging Correlation of the Pediatric Knee Growth.

Normal bone growth of the pediatric knee as well as normal variants of ossification result in different appearances that can be identified on imaging (radiography/MR imaging). Familiarity with these changes is important to avoid confusing normal growth with pathology. This article illustrates the main features related to normal bone growth (growth arrest lines, physeal changes, ossification centers within the epiphysis, hematopoietic marrow within the metaphysis) and physis disappearance (« FOPE ¼). Variants in femur (epiphyseal irregularities, subchondral anomalies of posterior condyles, periosteal desmoid), tibia (tibial tuberosity ossification), and patella (dorsal defect, bipartite patella, lower pole fragmentation) are also described.

Feasibility and outcome of an individualized Tai Chi program for improving balance and strength in the elderly: A pilot study.

BACKGROUND: Traditional Tai Chi is too complex for most elderly individuals. There have been few reports regarding the development of simplified Tai Chi programs to suit the physical needs of elderly adults. However, these programs were not individualized according to the participants' balance control abilities. OBJECTIVE: Purpose of this study is to develop an individualized Tai Chi program and report the feasibility of the program. METHODS: Phase 1: Five Tai Chi masters performed the Tai Chi movements on a force platform. Based on the results of center of pressure displacement and the individual's balance abilities, an individualized program was developed.Phase 2: Ten community-dwelling older adults received 24 half-hour-sessions, using the individualized Tai Chi exercise program. The Berg Balance Scale (BBS) score, Timed Up & Go (TUG) test, forward reach, and strength of the knee extensor were determined before and after intervention. RESULTS: Participants achieved improved performance on balance control as measured with BBS (p≤0.001), TUG (p = 0.004) and forward reach (p = 0.035) as well as knee extensor strength (p = 0.002) after the program. CONCLUSIONS: This preliminary result suggests that the individualized Tai Chi program is potentially effective to improve balance function and knee extensor strength of the elderly.

Comparison of the Viability and Yield of Adipose-Derived Stem Cells (ASCs) from Different Donor Areas.

BACKGROUND: Adipose tissue contains variable amounts of stem cells that have recently attracted increased interest due to their strong proliferative and differentiation capacity. However, significant heterogeneity exists in terms of stem cell yield and viability profile among individuals as well as different donor areas. MATERIALS AND METHODS: Between June 2016 and July 2016, forty (40) women underwent outpatient cosmetic liposuction procedures conferring a total of 53 lipoaspirates; inner thigh (n=13), outer thigh (n=9), abdomen (n=9), waist (n=16) and inner knee (n=6). Lipoaspirates were harvested using a tulip low-pressure syringe lipoaspiration system with a diameter of 3 mm. Centrifugation separated adipocytes from the stromal vascular fraction (SVF). Isolation of the adipose-derived stem cells (ASCs) was achieved through culture of the SVF. Viability of SVF cells and ASCs was evaluated with trypan blue dye under microscope and using flow cytometry with 7-AAD staining, respectively. Total cell count was estimated for both the SVF and ASCs. RESULTS: Outer thigh exhibited significantly higher SVF cell count compared to any other donor site (p<0.05). In addition, inner and outer thigh showed a significantly higher number of ASCs compared to abdominal, waist, and inner knee samples (p<0.05). Finally, viability of SVF cells (range, 94-95%) and ASCs (range, 93.12-96.14%) was excellent with no significant differences among donor areas. CONCLUSION: Tissue-harvesting area is a strong determinant of the quality of the fat grafts. Compared to abdomen, waist and inner knee, thighs seem favorable in terms of viability profile and yield of SVF cells and ASCs. Further randomized controlled trials incorporating a larger cohort of patients are warranted in order to verify our results.

Effects of age and sex on fatigability and recovery from a sustained maximal isometric voluntary contraction.

The aim was to assess the effects of sex and age on fatigability and recovery from sustained maximal voluntary contraction (MVC) of the knee extensor muscles. The central (central activation ratio (CAR) and electrical activity amplitude) and peripheral (electrically evoked torque and muscle contractile properties) factors contributing to fatigue and recovery of 24 young adults (12 males) aged 23.2±3.6years and 20 older adults (12 males) aged 70.6±4.4years were compared. The increase in central and peripheral fatigue was greater (p⩽0.01) in the young adults vs the older adults. Sex differences (p=0.002) regarding MVC were attributed to the greater (p<0.01) peripheral fatigue of males vs females. The recovery rate of MVC was greater (p<0.001) in the young adults vs the older adults, with no sex effect. The recovery of MVC was correlated with the CAR in older adults (p=0.001). Thus, the greater endurance observed with age is caused by differences in central and peripheral mechanisms, whereas the greater endurance in females is caused by a difference in a mechanism located within the muscle. The impaired recovery from fatigue in older adults relied more on the recovery of central factors.

Heads, Shoulders, Elbows, Knees, and Toes: Modular Gdf5 Enhancers Control Different Joints in the Vertebrate Skeleton.

Synovial joints are crucial for support and locomotion in vertebrates, and are the frequent site of serious skeletal defects and degenerative diseases in humans. Growth and differentiation factor 5 (Gdf5) is one of the earliest markers of joint formation, is required for normal joint development in both mice and humans, and has been genetically linked to risk of common osteoarthritis in Eurasian populations. Here, we systematically survey the mouse Gdf5 gene for regulatory elements controlling expression in synovial joints. We identify separate regions of the locus that control expression in axial tissues, in proximal versus distal joints in the limbs, and in remarkably specific sub-sets of composite joints like the elbow. Predicted transcription factor binding sites within Gdf5 regulatory enhancers are required for expression in particular joints. The multiple enhancers that control Gdf5 expression in different joints are distributed over a hundred kilobases of DNA, including regions both upstream and downstream of Gdf5 coding exons. Functional rescue tests in mice confirm that the large flanking regions are required to restore normal joint formation and patterning. Orthologs of these enhancers are located throughout the large genomic region previously associated with common osteoarthritis risk in humans. The large array of modular enhancers for Gdf5 provide a new foundation for studying the spatial specificity of joint patterning in vertebrates, as well as new candidates for regulatory regions that may also influence osteoarthritis risk in human populations.

Sexual dimorphism in growth in the relative length of the forearm and relative knee height during adolescence.

There are numerous studies concerning sexual dimorphism in body proportions, but only a few have investigated growth in the relative length of particular segments of the upper and lower limbs during adolescence. The aim of the study is an assessment of sex differences of longitudinal growth in the relative length of the forearm and knee height among adolescents. Sample involved 121 boys and 111 girls, participants of the Wroclaw Growth Study, examined annually between 8 and 18 years of age. Sexual dimorphism in six ratios: forearm length and knee height relatively to: trunk, height, and limb length were analyzed using a two-way analysis of variance with repeated measurements. The sex and age relative to an estimate of maturity timing (3 years before, and after age class at peak height velocity [PHV]) were independent variables. All of the ratios showed significant sex differences in interaction with age relative to age at PHV. The relative length of the forearm, in boys, did not change significantly with the years relative to age at PHV, whereas in girls, was the lowest in the two first age classes and afterward significantly increased just 1 year before and during the adolescent growth spurt, remaining unchanged in further age classes. For relative knee height no clear pattern for sex differences was noticed. It is proposed that relatively longer forearms, particularly in relation to the trunk in girls, could have evolved as an adaptation to more efficient infant carrying and protection during breastfeeding.

Muscle disuse alters skeletal muscle contractile function at the molecular and cellular levels in older adult humans in a sex-specific manner.

Physical inactivity that accompanies ageing and disease may hasten disability by reducing skeletal muscle contractility. To characterize skeletal muscle functional adaptations to muscle disuse, we compared contractile performance at the molecular, cellular and whole­muscle levels in healthy active older men and women (n = 15) and inactive older men and women with advanced­stage, symptomatic knee osteoarthritis (OA) (n = 16). OA patients showed reduced (P < 0.01) knee extensor function. At the cellular level, single muscle fibre force production was reduced in OA patients in myosin heavy chain (MHC) I and IIA fibres (both P < 0.05) and differences in IIA fibres persisted after adjustments for fibre cross­sectional area (P < 0.05). Although no group differences in contractile velocity or power output were found for any fibre type, sex was found to modify the effect of OA, with a reduction in MHC IIA power output and a trend towards reduced shortening velocity in women, but increases in both variables in men (P < 0.05 and P = 0.07, respectively). At the molecular level, these adaptations in MHC IIA fibre function were explained by sex­specific differences (P ≤ 0.05) in myosin­actin cross­bridge kinetics. Additionally, cross­bridge kinetics were slowed in MHC I fibres in OA patients (P < 0.01), attributable entirely to reductions in women with knee OA (P < 0.05), a phenotype that could be reproduced in vitro by chemical modification of protein thiol residues. Our results identify molecular and cellular functional adaptations in skeletal muscle that may contribute to reduced physical function with knee OA­associated muscle disuse, with sex­specific differences that may explain a greater disposition towards disability in women.

Anterior cruciate ligament injuries in children and adolescents: a review of the recent literature.

In contrast to the treatment of avulsion lesions of the anterior cruciate ligament (ACL) the management of intrasubstance ACL tears in the skeletally immature patient remains controversial. Prospective studies could show that conservative treatment results in severe instability with concomitant intraarticular damage and poor function of the knee. Reconstruction of a torn ACL always carries the risk of damaging the open growth plates; with consecutively affecting the longitudinal or axial growth of the lower extremity either on the femoral or the tibial side. Thus, several surgical procedures are available to prevent adverse events mentioned above. The purpose of this study is to review the recent literature regarding the treatment algorithm for ACL injuries in skeletally immature patients. This review will (1) investigate the indications for ACL surgery in children; (2) determine if a surgical procedure is clinically superior in skeletally immature patients; and (3) correlate the adverse events with the surgical technique.

Longitudinal shrinkage in lower legs: "negative growth" in healthy late-adolescent males.

BACKGROUND/AIMS: We examined the final period of tibial growth in late adolescent males. METHODS: Forty-one healthy male subjects, aged 15.7 to 19.8 years participated in a study on lower leg length (LLL) growth, body height and weight increments. All subjects were measured and weighed at weekly intervals over a period of one year. Body height was determined by an anthropometer, body weight by conventional scales, and LLL was measured by a hand-held knemometer. The state of maturity of the proximal tibial epiphyses was determined by magnetic resonance imaging (MRI). Skeletal maturity was independently assessed by two radiologists. The growth plates were categorized as being open (category I), centrally but not completely fused (category II), or completely fused (category III). RESULTS: Our findings demonstrate that in these adolescents, final tibial growth is characterized by longitudinal shrinkage. As shown in the MRI, when the proximal tibial growth plates have fused (i.e., at an age when lower leg growth is commonly believed to have completed), the lower leg of healthy adolescent males begins to shrink with a negative growth rate of -2.4 (SD 2.1) mm/year. CONCLUSION: Apart from sporadic observations in anorectic girls, longitudinal shrinkage in LLL has not been previously documented. We assume that the final period of growth includes small reductions in bone length, possibly due to stabilization and rearrangements in the formerly growing cartilaginous tissues.