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Purpose The effective mechanical advantage (EMA) of the plantarflexor muscles is important for gait function and is likely different from typical in equinus gait. However, this has never been quantified for children who idiopathically toe-walk (ITW), despite being routinely altered through clinical intervention. Methods This study quantified the Achilles tendon and ground reaction force (GRF) moment arms, and the plantarflexor EMA of 5 children who ITW and 14 typically developing (TD) children, whilst walking on an instrumented treadmill. Results There was no difference in the Achilles tendon moment arm length throughout stance between groups (p > 0.05). Children who ITW had a significantly greater GRF moment arm length in early stance (20–24% p = 0.001), but a significantly shorter GRF moment arm length during propulsion (68–74% of stance; p = 0.013) than TD children. Therefore, children who ITW had a greater plantarflexor EMA than TD children when active plantarflexion moments were being generated (60–70% of stance; p = 0.007). Consequently, it was estimated that children who ITW required 30% less plantarflexor muscle force for propulsion. Conclusion Clinical decision making should fully consider that interventions which aim to restore a typical heel-toe gait pattern risk compromising this advantageous leverage and thus, may increase the strength requirements for gait.

The original version of this article unfortunately contained a mistake. The original abstract was published on 16th March 2022. https://doi.org/10.1007/s00421-022-04913-7

Children who idiopathically toe‐walk (ITW) habitually operate at greater plantarflexion angles and thus, at shorter muscle‐tendon unit (MTU) lengths than typically developing (TD) children. Therefore, it is often assumed that habitual use of the gastrocnemius muscle in this way will cause remodelling of the muscle‐tendon architecture compared to TD children. However, the gastrocnemius muscle architecture of children who ITW has never been measured. It is essential that we gain a better understanding of these muscle‐tendon properties, to ensure that appropriate clinical interventions can be provided for these children. Five children who ITW (age 8 ± 2 years) and 14 TD children (age 10 ± 2 years) participated in this study. Ultrasound was combined with isokinetic dynamometry and surface electromyography, to measure muscle architecture at common positions and passive lengthening properties of the gastrocnemius muscle and tendon across full range of motion. Regardless of which common condition groups were compared under, both the absolute and normalised to MTU muscle belly and fascicle lengths were always longer, and the Achilles tendon length was always shorter in children who ITW than TD children (p 0.05); however, passive joint stiffness was greater in children who ITW at maximum dorsiflexion (p = 0.001) and at a joint moment common to all participants (p = 0.029). Consequently, the findings of this pilot study indicate a remodelling of the relative MTU that does not support the concept that children who ITW commonly experience muscle shortening. Therefore, greater consideration of the muscle and tendon properties are required when prescribing clinical interventions that aim to lengthen the MTU, and treatments may be better targeted at the Achilles tendon in children who ITW., We used ultrasound to measure the gastrocnemius medialis muscle architecture in children who idiopathically toe‐walk (ITW). Despite habitually operating at shorter muscle‐tendon unit lengths, children who ITW presented with longer muscle and shorter tendon lengths than typically developing children. Therefore, these findings indicate a remodelling of the relative muscle‐tendon unit that does not support the concept that children who ITW commonly experience muscle shortening.

Data Availability Statement: The datasets generated for this study are available on request to the corresponding author. Copyright © 2020 Harkness-Armstrong, Debelle, Maganaris, Walton, Wright, Bass, Baltzopoulos and O’Brien. Aim: To study the causes of locomotor dysfunction, estimate muscle forces, or understand the influence of altered sarcomere and muscle properties and behaviours on whole body function, it is necessary to examine the leverage with which contractile forces operate. At the ankle joint, current methods to quantify this leverage for the plantarflexors do not account for curvature of the Achilles tendon, and so may not be appropriate when studying equinus gait. Thus, novel methodologies need to be developed and implemented to quantify the Achilles tendon moment arm length during locomotion. Methods: Plantarflexor internal moment arm length and effective mechanical advantage of 11 typically developed young adults were calculated throughout stance, while heel-toe walking and voluntarily toe-walking on an instrumented treadmill. Achilles tendon moment arm was defined in two-ways: (1) assuming a straight tendon, defined between the gastrocnemius medialis myotendinous junction and Achilles tendon insertion point, and (2) accounting for tendon curvature, by tracking the initial path of the Achilles tendon from the calcaneal insertion. Results: When accounting for tendon curvature, Achilles tendon moment arm length and plantarflexor effective mechanical advantage did not differ between walking conditions (p > 0.05). In contrast, when assuming a straight tendon, Achilles tendon moment arm length (p = 0.043) and plantarflexor effective mechanical advantage (p = 0.007) were significantly greater when voluntary toe-walking than heel-toe walking in late stance. Discussion: Assuming a straight Achilles tendon led to a greater Achilles tendon moment arm length and plantarflexor effective mechanical advantage during late stance, compared to accounting for tendon curvature. Consequently, plantarflexor muscle force would appear smaller when assuming a straight tendon. This could lead to erroneous interpretations of muscular function and fascicle force-length-velocity behaviour in vivo, and potentially inappropriate and ineffective clinical interventions for equinus gait. Liverpool John Moores University Ph.D. scholarship.

When studying muscle and whole-body function in children with cerebral palsy (CP), knowledge about both internal and external moment arms is essential since they determine the mechanical advantage of a muscle over an external force. Here we asked if Achilles tendon moment arm (MAAT) length is different in children with CP and age-matched typically developing (TD) children, and if MAAT can be predicted from anthropometric measurements. Sixteen children with CP (age: 10y 7 m ± 3y, 7 hemiplegia, 12 diplegia, GMFCS level: I (11) and II (8)) and twenty TD children (age: 10y 6 m ± 3y) participated in this case-control study. MAAT was calculated at 20° plantarflexion by differentiating calcaneus displacement with respect to ankle angle. Seven anthropometric variables were measured and related to MAAT. We found normalized MAAT to be 15% (∼7 mm) smaller in children with CP compared to TD children (p = 0.003). MAAT could be predicted by all anthropometric measurements with tibia length explaining 79% and 72% of variance in children with CP and TD children, respectively. Our findings have important implications for clinical decision making since MAAT influences the mechanical advantage about the ankle, which contributes to movement function and is manipulated surgically.

Background Flexion deformity of the knee is a common presentation in children with cerebral palsy with hamstring surgery as an option for addressing this. However, concerns with regard to increased pelvic tilt have been raised. The purpose of this study was to compare preoperative and postoperative pelvic tilt after isolated hamstring lengthening versus combined hamstring lengthening and the influence of Gross Motor Function Classification System (GMFCS) levels on pelvic tilt. Methods This retrospective study included 46 ambulatory children with cerebral palsy who had had open medial hamstring lengthening (mean age at surgery, 11 y 11 mo; SD, 2 y 11 mo; GMFCS I, 16; GMFCS II 20; GMFCS III 10). Twelve children underwent isolated surgery and 34 children underwent combined surgery. The isolated hamstring procedures could be combined with foot and/or ankle-level surgery, as only the hamstring procedure would affect the pelvic tilt. Combined surgery was defined as hamstring lengthening with other procedures performed at the knee or more proximally. The preoperative and postoperative 3-dimensional gait analysis data were evaluated in this study. Results Both the isolated and combined hamstring lengthening groups showed no significant change in pelvic tilt ([INCREMENT]1.28, P=0.203; [INCREMENT]1.47, P=0.113, respectively). A significant change in pelvic tilt was seen in children functioning at GMFCS III ([INCREMENT]4.66, P=0.009) but not GMFCS I and II ([INCREMENT]0.37, P=0.718; [INCREMENT]0.48, P=0.697). Significant postoperative decreases in the knee flexion angle at initial contact were seen for both isolated ([INCREMENT]5.72, P=0.010) and combined hamstring lengthening ([INCREMENT]10.95, P Conclusions Hamstring lengthening, for the majority of patients, did not lead to a clinically significant change in mean pelvic tilt and improved knee flexion angle at initial contact. Children who functioned at GMFCS level III had an increase in anterior pelvic tilt and caution should be exercised in this group. Study design Level IV evidence-case series.

NEW FINDINGS: What is the central question of this study? Which structures of the medial gastrocnemius muscle-tendon unit contribute to its lengthening during joint rotation and thus receive the stretching stimulus? What is the main finding and its importance? We show, for the first time, that muscle and tendon lengthen in a different manner in children with cerebral palsy compared with typically developing children during a similar amount of muscle-tendon unit lengthening or joint rotation. This indicates possible differences in mechanical muscle and tendon properties attributable to cerebral palsy, which are not evident by assessment of muscle function at the level of a joint. ABSTRACT: Children with cerebral palsy (CP) commonly present with reduced ankle range of motion (ROM) attributable, in part, to changes in mechanical properties of the muscle-tendon unit (MTU). Detailed information about how muscle and tendon interact to contribute to joint rotation is currently lacking but might provide essential information to explain the limited effectiveness of stretching interventions in children with CP. The purpose of this study was to quantify which structures contribute to MTU lengthening and thus receive the stretch during passive ankle joint rotation. Fifteen children with CP (age, in mean ± SD, 11.4 ± 3 years) and 16 typically developing (TD) children (age, in mean ± SD, 10.2 ± 3 years) participated. Ultrasound was combined with motion tracking, joint torque and EMG to record fascicle, muscle and tendon lengthening of the medial gastrocnemius during passive ankle joint rotations over the full ROM and a common ROM. In children with CP, relative to MTU lengthening, muscle and fascicles lengthened less (CP, 50.4% of MTU lengthening; TD, 63% of MTU lengthening; P

Gait analysis provides detailed objective quantitative measurements with regards to locomotion. The process of gait analysis involves the evaluation of a combination of data. This includes the visual observation of gait, a standardized clinical examination and instrumented analysis. Biomechanical data including joint movements and forces can be quantified and define the segmental movements of the limbs. This allows an accurate quantification of the deviations away from normal gait parameters and using that data to understand deformity and pathology, plan surgical strategy and objectively measure outcomes subsequent to intervention. Whether gait analysis leads to significant improvement in structural abnormalities, gait, function, quality of life, and cost-effectiveness is still yet to be determined.

We compared two commonly used methods of immobilization of Gartland type I supracondylar humeral fractures, with respect to pain control, use of analgesia and sleep interruption. Forty patients were included in the study, collar and cuff immobilization (group 1, n=20) and above elbow back slab immobilization (group 2, n=20). Diagnosis was made in the accident department and patients were immobilized (collar and cuff or back slab) according to the preference of the treating doctor. Patients were then reviewed in the next available fracture clinic where they were assessed. The Wong-Baker faces scale was used to measure pain. Patients immobilized with a collar and cuff had an average pain score of 7.2 compared with 3.4 for those immobilized with a back slab (P

We undertook a retrospective comparative study of all patients with an unstable slipped capital femoral epiphysis presenting to a single centre between 1998 and 2011. There were 45 patients (46 hips; mean age 12.6 years; 9 to 14); 16 hips underwent intracapsular cuneiform osteotomy and 30 underwent pinning in situ, with varying degrees of serendipitous reduction. No patient in the osteotomy group was lost to follow-up, which was undertaken at a mean of 28 months (11 to 48); four patients in the pinning in situ group were lost to follow-up, which occurred at a mean of 30 months (10 to 50). Avascular necrosis (AVN) occurred in four hips (25%) following osteotomy and in 11 (42%) following pinning in situ. AVN was not seen in five hips for which osteotomy was undertaken > 13 days after presentation. AVN occurred in four of ten (40%) hips undergoing emergency pinning in situ, compared with four of 15 (47%) undergoing non-emergency pinning. The rate of AVN was 67% (four of six) in those undergoing pinning on the second or third day after presentation.Pinning in situ following complete reduction led to AVN in four out of five cases (80%). In comparison, pinning in situ following incomplete reduction led to AVN in 7 of 21 cases (33%). The rate of development of AVN was significantly higher following pinning in situ with complete reduction than following intracapsular osteotomy (p = 0.048). Complete reduction was more frequent in those treated by emergency pinning and was strongly associated with AVN (p = 0.005).Non-emergency intracapsular osteotomy may have a protective effect on the epiphyseal vasculature and should be undertaken with a delay of at least two weeks. The place of emergency pinning in situ in these patients needs to be re-evaluated, possibly in favour of an emergency open procedure or delayed intracapsular osteotomy. Non-emergency pinning in situ should be undertaken after a delay of at least five days, with the greatest risk at two and three days after presentation. Intracapsular osteotomy should be undertaken after a delay of at least 14 days. In our experience, closed epiphyseal reduction is harmful.Cite this article: Bone Joint J 2015;97-B:412–19.

A 13 year old boy presented to the accident and emergency department because he was unable to bear weight on his left leg and had a history of pain in the left knee. The pain began 10 days before, after a fall, at which time he had a dull pain in his knee but was still able to bear weight. Three days before his attendance he tripped again, and after this injury, the pain had become more severe and he was unable to bear weight. He was otherwise healthy, with no history of joint problems. He was not particularly active or sporty and had a body mass index of 25.6. On examination, he was in moderate pain and was unable to bear weight. Both knees were normal, but his left leg was shortened and externally rotated, with no evidence of bruising or injury. Examination of his left hip showed limitation of flexion, abduction, and, in particular, internal rotation because of pain. All other joint examinations were unremarkable. He underwent radiography (fig 1⇓). ### 1 What type of radiograph is this and what does it show? #### Short answer Figure 1 is a “frog lateral” radiograph and it shows a widened physis and malalignment of the epiphysis and proximal femoral metaphysis (fig 2⇓), confirming the diagnosis of a left slipped upper femoral epiphysis. Fig 2 Frog lateral radiograph showing a widened physis and malalignment of the epiphysis and proximal femoral metaphysis on the left side #### Long answer Slipped upper femoral epiphysis is the transphyseal displacement of the upper femoral epiphysis from the metaphysis.1 Frog lateral (while the patient is supine with both knees flexed, soles …

We present a case report on transverse divergent dislocation of the elbow, highlighting the spatial relation among the proximal radius, ulna, and distal humerus in this rare pediatric elbow injury and reasons leading to misinterpretation of radiographs. Elbow dislocation is a rare injury in children. It comprises only 6% of pediatric elbow injuries. Most pure dislocations are posterior, but they can occur in any direction. Divergent dislocation of the elbow is a subgroup of posterior dislocation, which is extremely rare. It is important that the pediatric emergency physician is aware, able to identify, and manage this injury. It is defined as a specific elbow dislocation in which the distal humerus is forced between the proximal radius and ulna, resulting in the divergence of the proximal forearm bones. Joint laxity is said to be a predisposing cause in pediatric age group. Atraumatic divergent dislocation of the elbow has been reported in the adults with rheumatoid arthritis. Imaging is challenging because there is no defined specific radiological views, therefore making the diagnosis difficult. This often leads to misdiagnosis or inappropriate treatment. A thorough understanding of mechanism of injury and basis for atypical radiological findings will help in identifying the injury early, and the simple Thompson technique to relocate the elbow will give an excellent functional outcome.

Elastic stable intramedullary nailing (ESIN) for displaced forearm fractures in children has shown good results over the last two decades. To our knowledge, nonunion as complications after ESIN fixation of displaced forearm fractures is not well reported in English literature. In our institute, and over a period of 10 years, we identified three cases of nonunion of the ulna after ESIN fixation of unstable and displaced forearm both bone fractures. Two patients had closed fractures and one patient had an open fracture. There was no deep infection in any case. All cases after revision surgery went into union.

Purpose We have reported the radiological and clinical outcome of scarf osteotomy in the treatment of moderate to severe hallux valgus among adolescent children. Method Data were collected retrospectively between April 2001 and June 2006. The pre- and post-operative intermetatarsal angle (IMA), hallux valgus angle (HVA) and distal metatarsal articular angle (DMAA) were determined. Patients were followed up for a mean of 37.6 months. Results Thirteen patients with 19 operated feet were available at the time of the latest follow-up. There was significant improvement in the mean post-operative IMA, which was maintained to the last follow-up. There was statistically significant improvement in the 6-week post-operative HVA and DMAA. However, this was lost at the final follow-up. The mean American Orthopaedic Foot and Ankle Society score for the whole group was 80 (54–100). Conclusion This study indicates that scarf osteotomy should be used with caution in symptomatic adolescent hallux valgus, as there is a high recurrence rate.

New Findings: What is the central question of this study? Can the increased range of motion seen acutely after stretching in children with cerebral palsy be explained by changes in the stiffness of the medial gastrocnemius fascicles? What is the main finding and its importance? We show, for the first time, that passive muscle and tendon properties are not changed acutely after a single bout of stretching in children with cerebral palsy and, therefore, do not contribute to the increase in range of motion. This contradicts common belief and what happens in healthy adults. Abstract: Stretching is often used to increase or maintain the joint range of motion (ROM) in children with cerebral palsy (CP), but the effectiveness of these interventions is limited. Therefore, our aim was to determine the acute changes in muscle–tendon lengthening properties that contribute to increased ROM after a bout of stretching in children with CP. Eleven children with spastic CP [age 12.1 (3 SD) years, 5/6 hemiplegia/diplegia, 7/4 gross motor function classification system level I/II] participated. Each child received three sets of five × 20 s passive, manual static dorsiflexion stretches separated by 30 s rest, with 60 s rest between sets. Before and immediately after stretching, ultrasound was used to measure medial gastrocnemius fascicle lengthening continuously over the full ROM and an individual common ROM pre- to post-stretching. Simultaneously, three-dimensional motion of two marker clusters on the shank and the foot was captured to calculate ankle angle, and ankle joint torque was calculated from manually applied torques and forces on a six degrees-of-freedom load cell. After stretching, the ROM was increased [by 9.9 (12.0) deg, P = 0.005]. Over a ROM common to both pre- and post-measurements, there were no changes in fascicle lengthening or torque. The maximal ankle joint torque tolerated by the participants increased [by 2.9 (2.4) N m, P = 0.003], and at this highest passive torque the maximal fascicle length was 2.8 (2.4) mm greater (P = 0.009) when compared with before stretching. These results indicate that the stiffness of the muscle fascicles in children with CP remains unaltered by an acute bout of stretching.