A Recess Is Observed Between the Posterior Knee Capsule and the Meniscotibial Ligament Complex in Pediatric Specimens.

Purpose: To define the surgical anatomy of the meniscotibial ligament complex of the pediatric medial and lateral menisci and their relation to the proximal tibial physis and posterior joint capsule. Methods: Fourteen pediatric cadaveric knee specimens (aged 3 months to 11 years) were dissected to clarify the relation of the posterior knee capsule, the meniscus, and the meniscotibial ligament complex. Metallic markers were placed marking the meniscotibial ligament capsular attachment on the proximal tibia. Specimens underwent computed tomography scanning to evaluate pin placement and relation to the physis. A digital measurement tool was used to measure the distances between the proximal tibial physis and the pins (placed at 5 points on both the lateral and medial menisci). Results: In each specimen, clear separation was noted between the posterior joint capsule from the meniscus and meniscotibial ligament complex in the medial and lateral compartments. There was an increase in the distance between the proximal tibial physis and the insertion points of the meniscotibial ligament complex with increasing specimen age. For both the medical and lateral menisci in group 1, the median meniscotibial ligament insertion points were often less than 7 mm (interquartile range, 0.00-7.8 mm) away from the physis. The median meniscotibial ligament insertion points in group 2 tended to be farther from the physis but always less than 20 mm (interquartile range, 2.5-17.5 mm)-and as close as less than 5 mm (lateral posterior root). Conclusions: In this anatomic study of pediatric knees, we observed a distinct recess/cul-de-sac space between the posterior knee capsule and meniscal attachments in all specimens. This defines a distinct plane between the posterior knee capsule and the meniscotibial ligament complex, with a distance between the physis and meniscotibial ligament capsular attachments that increases with age. Clinical Relevance: The anatomic parameters evaluated in our study should be considered as future meniscal repair and transplantation techniques aim to restore the meniscal anatomy, stability, and mobility provided by the meniscotibial ligament complex and capsule structures.

Optimizing exoskeleton assistance to improve walking speed and energy economy for older adults.

BACKGROUND: Walking speed and energy economy tend to decline with age. Lower-limb exoskeletons have demonstrated potential to improve either measure, but primarily in studies conducted on healthy younger adults. Promising techniques like optimization of exoskeleton assistance have yet to be tested with older populations, while speed and energy consumption have yet to be simultaneously optimized for any population. METHODS: We investigated the effectiveness of human-in-the-loop optimization of ankle exoskeletons with older adults. Ten healthy adults > 65 years of age (5 females; mean age: 72 ± 3 yrs) participated in approximately 240 min of training and optimization with tethered ankle exoskeletons on a self-paced treadmill. Multi-objective human-in-the-loop optimization was used to identify assistive ankle plantarflexion torque patterns that simultaneously improved self-selected walking speed and metabolic rate. The effects of optimized exoskeleton assistance were evaluated in separate trials. RESULTS: Optimized exoskeleton assistance improved walking performance for older adults. Both objectives were simultaneously improved; self-selected walking speed increased by 8% (0.10 m/s; p = 0.001) and metabolic rate decreased by 19% (p = 0.007), resulting in a 25% decrease in energetic cost of transport (p = 8e-4) compared to walking with exoskeletons applying zero torque. Compared to younger participants in studies optimizing a single objective, our participants required lower exoskeleton torques, experienced smaller improvements in energy use, and required more time for motor adaptation. CONCLUSIONS: Our results confirm that exoskeleton assistance can improve walking performance for older adults and show that multiple objectives can be simultaneously addressed through human-in-the-loop optimization.

Can Caregivers Forecast Their Child's Postoperative Disability After Elective Orthopedic Surgery?

Background While there has been a growing emphasis on evaluating the patient's perspective of health outcomes, caregiver expectations of post-orthopedic procedure disability and pain in a pediatric population are yet to be investigated. This study evaluates whether caregivers' preoperative expectations of pain and function differ from their child's early outcomes after surgical orthopedic intervention. Methodology Patients eight to 18 years old undergoing elective orthopedic surgery were enrolled. The caregivers of consented patients completed a survey at the child's preoperative appointment to predict their postoperative pain and disability. The child was given the same survey during their postoperative visit four to six weeks after surgery to assess actual levels of functioning following the procedure. Scores were analyzed to study correlations between patient and caregiver responses (n = 48). Results Caregivers underestimated their child's postoperative psychosocial functioning, as evidenced by the Psychosocial Health Summary Score, and overestimated pain, as demonstrated by the Numeric Pain Rating Scale. The Pediatric Quality of Life Inventory scores showed caregivers had differing expectations of the impact surgery had across various aspects of the physical, emotional, social, and school functioning domains. Higher parental pain catastrophizing was associated with underestimated predictions of their child's psychosocial functioning after surgery. No significant difference was found in the patient's physical functioning, as shown by the Physical Health Summary Score. Conclusions Surgical intervention is a major event that can provoke anxiety for parents and caregivers. Understanding differences in caregiver perspectives and early postoperative patient outcomes provides physicians valuable insights. Explaining to caregivers that patient psychosocial factors and functional outcomes after surgery are commonly better than expected can alleviate anxiety and prevent catastrophizing. This knowledge can help guide caregiver expectations and plans for their child's postoperative pain control and functional recovery.

Wearable Sensory Substitution for Proprioception via Deep Pressure.

We propose a sensory substitution device that communicates one-degree-of-freedom proprioceptive feedback via deep pressure stimulation on the arm. The design is motivated by the need for a feedback modality detectable by individuals with a genetic condition known as PIEZO2 loss of function, which is characterized by absence of both proprioception and sense of light touch. We created a wearable and programmable prototype that applies up to 15 N of deep pressure stimulation to the forearm and includes an embedded force sensor. We conducted a study to evaluate the ability of participants without sensory impairment to control the position of a virtual arm to match a target angle communicated by deep pressure stimulation. A participant-specific calibration resulted in an average minimum detectable force of 0.41 N and maximum comfortable force of 6.42 N. We found that, after training, participants were able to significantly reduce angle error using the deep pressure haptic feedback compared to without it. Angle error increased only slightly with force, indicating that this sensory substitution method is a promising approach for individuals with PIEZO2 loss of function and other forms of sensory loss.

Pediatric meniscus morphology varies with age: a cadaveric study.

PURPOSE: In adolescent patients, meniscal tear injury can occur either in isolation (e.g., discoid lateral meniscus tears) or in association with other traumatic injuries including tibial eminence fracture or ACL tear. Damage to meniscal integrity has been shown to increase contact pressure in articular cartilage, increasing risk of early onset osteoarthritis. In symptomatic patients failing conservative management, surgical intervention via meniscus repair or meniscus transplant is indicated. The purpose of this study was to evaluate the radial dimensions of pediatric menisci throughout development. The hypothesis was that the average radial meniscus dimensions will increase as specimen age increases, and mean medial and lateral region measurements will increase at a linear rate. METHODS: Seventy-eight skeletally immature knee cadaver specimens under age 12 years were included in this study. The meniscal specimens were photographed in the axial view with ruler in the plane of the tibial plateau and analyzed using computer-aided design (CAD) software (Autodesk Fusion 360). Measurements were taken from inner to outer meniscus rims at five 45 degree intervals using the clockface as a reference (12:00, 1:30, 3:00, 4:30, 6:00), and total area of meniscus and tibial plateau was recorded. Generalized linear models were used to evaluate the associations of radial width measurements with age, tibial coverage, and lateral vs. medial meniscus widths. RESULTS: All radial width measurements increased significantly with specimen age (p ≤ 0.002), and all lateral-medial meniscal widths increased (p < 0.001). The anterior zones of the meniscus were found to increase at the slowest rate compared to other regions. Tibial plateau coverage was found to not significantly vary with age. CONCLUSIONS: Meniscus radial width and lateral-medial meniscus width are related to age. The anterior width of the meniscus varied least with age. Improved anatomic understanding may help surgeons more effectively plan for meniscus repair, discoid resection/saucerization/repair, and also support appropriate selection of meniscus allograft for transplantation.

Knowledge and Practices Related to Hip-Healthy Swaddling for Newborns Among Maternity Nurses.

OBJECTIVE: To assess the self-reported knowledge, education, and practices related to hip-healthy swaddling of newborns among nurses, how they teach this technique to parents, and the relationships among these factors. DESIGN: Descriptive cross-sectional exploratory survey. SETTING: Academic women and children's hospital with an average of 4,500 annual births. PARTICIPANTS: One hundred four registered maternity nurses who work primarily in the maternity unit. METHODS: At three staff meetings, we surveyed maternity nurses to determine their knowledge, education, and practices related to hip-healthy swaddling and how they teach this technique to parents. We analyzed results using descriptive statistics and chi-square and Fisher's exact tests. RESULTS: Of the 156 nurses in the maternity unit, 104 attended three staff meetings and completed the survey. Among the participants, 18.9% (18/95; 9 participants did not respond) were unable to identify the correct hip swaddling position. Overall, 64.2% (61/95; 9 participants did not respond) reported that they received education on general swaddling technique, yet 14.8% (9/61) of these participants were unable to identify the correct hip-healthy swaddling position. Among the participants, 99.0% (103/104) reported that nurses teach parents how to swaddle infants rather than other health care providers; 12.5% (13/104) of participants responded that medical doctors provide training as well. Overall, 67.0% (69/103; 1 participant did not respond) reported that they taught parents in >75% of parent interactions. CONCLUSION: Our results illustrate a gap in knowledge about hip-healthy swaddling among the maternity nurses who participated in this survey and a need for further education.

Quantifying the Relationship Between the Medial Quadriceps Tendon-Femoral Ligament and Patellar Borders: A Pediatric Cadaveric Study.

BACKGROUND: The medial patellofemoral complex (MPFC) is a structure composed of the medial quadriceps tendon-femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The pediatric MPFL anatomy has been well described, but the precise anatomy of the MQTFL has only recently been described and studied in skeletally immature patients. PURPOSE: To describe the anatomic relationship between the MQTFL and its insertion on the quadriceps tendon and patella in pediatric specimens. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 22 pediatric cadaveric knee specimens were dissected to analyze attachment of the MQTFL to the quadriceps tendon and patella. Dissection was facilitated using lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate MQTFL fibers from its undersurface. RESULTS: The mean specimen age was 7.4 years. Specimens were divided based on age into a younger cohort (1-2 years), middle cohort (4-8 years), and older cohort (9-12 years). The quadriceps tendon attachment (QTA) of the MQTFL proximal to the patella extended a median of 5.0 mm in the younger cohort, 11.4 mm in the middle cohort, and 12.0 mm in the older cohort, with significant differences found between the younger and middle cohorts (P < .047) and the younger and older cohorts (P < .001). The QTA as a percentage of patellar articular height averaged 44.4% across all specimens. The vertical height of the patella measured a median of 14.0 mm, 22.3 mm, and 27.3 mm in the younger, middle, and older cohorts, respectively. CONCLUSION: This study expands on the recently described anatomy of the pediatric MPFC to quantify the anatomic relationship between the MQTFL attachment to the quadriceps tendon and patella in a more clinically relevant cohort of donor specimens. CLINICAL RELEVANCE: As access to pediatric cadaveric tissue is extremely limited, a better understanding of MPFC and MQTFL anatomy will support surgeons in preoperative planning and intraoperative considerations for their approach to MQTFL and MPFL reconstruction. This may facilitate improved anatomic surgical stabilization of the patellofemoral joint in pediatric patients.

Use of a novel pedal-operated compressor is non-inferior to the use of a standard hand-compressed bag-valve mask.

BACKGROUND: The standard bag-valve mask (BVM) used universally requires that a single healthcare practitioner affix the mask to the face with 1 hand while compressing a self-inflating bag with the second hand. Studies have demonstrated that creating a 2-handed seal (with 2 healthcare practitioners) is superior. Our study aims to assess the efficacy of a novel single-practitioner BVM device that uses a foot pedal as the bag compressor, allowing both hands to be available for the seal to facilitate delivery of appropriate tidal volumes during single-practitioner resuscitation. METHODS: This was a prospective, randomized, cross-over study. Participants with various BVM ventilation experience performed 2 minutes of metronome-guided BVM ventilation using a standard BVM and the pedal-operated compressor on a high-fidelity simulation mannequin. Analysis examining differences in mean tidal volume delivered was conducted using a regression model that adjusted for covariates. A secondary analysis using a series of Wilcoxon tests was conducted to compare differences in the additional out-of-range sensed breaths metrics to compare differences by prior BVM ventilation experience. RESULTS: A total of 58 subjects participated. The pedal-operated compressor unadjusted mean tidal volume delivered was 446.5 mL (95% confidence interval [CI], 425.9-467.1) compared with 340.6 mL (95% CI, 312.2-369.0) by standard BVM (mean change, 105.9 mL [95% CI, 71.2-140.6]; P < .001). When modeling a generalized estimation equation regression model, standard BVM ventilation provided a mean difference of 105.9 mL less than pedal-operated compressor ventilation after adjusting for covariates (P = 0.01). For the secondary outcome, the pedal-operated compressor did have a significantly lower median number of out-of-range breaths (median, 3; interquartile range [IQR], 1-11.5) compared with the standard device (median, 13.5; IQR, 6-19; P < 0.001). CONCLUSIONS: Use of a novel pedal-operated compressor may allow a single healthcare practitioner, regardless of prior experience, to deliver consistent, appropriate tidal volumes with more ease compared with the standard BVM during manual respiratory resuscitation.

Anterior Cruciate Ligament Length in Pediatric Populations: An MRI Study.

BACKGROUND: As regards anterior cruciate ligament (ACL) reconstruction (ACLR), graft diameter has been identified as a major predictor of failure in skeletally mature patients; however, this topic has not been well-studied in the higher risk pediatric population. Hamstring tendon autograft configuration can be adjusted to increase graft diameter, but tendon length must be adequate for ACLR. Historical parameters of expected tendon length have been variable, and no study has quantified pediatric ACL morphology with other osseous parameters. PURPOSE: To develop magnetic resonance imaging (MRI)-derived predictors of native ACL graft length in pediatric patients so as to enhance preoperative planning for graft preparation in this skeletally immature patient population. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: MRI scans of 110 patients were included (64 girls, 46 boys; median age, 10 years; range, 1-13 years). Patients with musculoskeletal diseases or prior knee injuries were excluded. The following measurements were taken on MRI: ACL length; sagittal and coronal ACL inclination; intercondylar notch width and inclination; and femoral condyle depth and width. Associations between these measurements and patient sex and age were investigated. Univariate linear regression and multivariable regression models were created for each radiographic ACL measure to compare R 2. RESULTS: Female ACL length was most strongly associated with the depth of the lateral femoral condyle as viewed in the sagittal plane (R 2 = 0.65; P < .001). Other statistically significant covariates of interest included distal femoral condylar width, age, and coronal notch width (P < .05). For males, the ACL length was most strongly associated with the distal femoral condyle width as viewed in the coronal plane (R 2 = 0.70; P < .001). Other statistically significant covariates of interest for male ACL lengths were lateral femoral condyle depth, age, and coronal notch width (P < .05). CONCLUSION: In pediatric populations, femoral condylar depth/width and patient age may be valuable in assessing ACL size and determining appropriate graft dimensions and configuration for ACLRs. The use of this information to optimize graft diameter may lower the rates of ACL graft failure in this high-risk group.

Doxycycline preserves chondrocyte viability and function in human and calf articular cartilage ex vivo.

Prolonging chondrocyte survival is essential to ensure fresh osteochondral (OC) grafts for treatment of articular cartilage lesions. Doxycycline has been shown to enhance cartilage growth, disrupt terminal differentiation of chondrocytes, and inhibit cartilage matrix degradation. It is unknown whether doxycycline prolongs chondrocyte survival in OC grafts. We hypothesized that doxycycline protects against chondrocyte death and maintains function of articular cartilage. To test this hypothesis, we employed human and calf articular cartilages, and incubated chondrocytes isolated from cartilage or cartilage plugs with doxycycline (0, 1 or 10 µg/ml) at either 37°C or 4°C. Chondrocyte viability, apoptosis, glycosaminoglycan (GAG), collagen, and mechanical test in cartilage plugs were measured. We found that reduced chondrocyte viability, increased chondrocyte apoptosis, reduced GAG contents, and impaired equilibrium modulus in cartilage plugs were observed in a time-dependent manner at both 37°C and 4°C. Chondrocyte viability was further reduced when the plugs were cultured at 4°C as compared to 37°C. Doxycycline prolonged viability and reduced apoptosis of chondrocytes during culture of cartilage plugs. Functionally, doxycycline protected against reduced production of GAG and collagen II as well as impaired mechanical properties in cartilage plugs during culture. Mechanistically, doxycycline increased mitochondrial respiration in cultured chondrocytes. In conclusion, preservation at 37°C is beneficial for maintaining chondrocyte viability in cartilage plugs compared to 4°C. Incubation of doxycycline protects against chondrocyte apoptosis, reduced extracellular matrix, and impaired mechanical properties in cartilage plugs. The findings provide a potential approach using doxycycline at 37°C to preserve chondrocyte viability in fresh OC grafts for treatment of articular cartilage lesions.