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The management of type 3 lateral condyle fractures (LCFs) remains controversial. The main goal of this study was to evaluate the feasibility of closed reduction and percutaneous pinning (CRPP) in patients with type 3 LCFs and to assess the outcome of such injuries according to the type of treatment, CRPP, or open reduction and internal fixation (ORIF).This is a retrospective review of prospectively enrolled children with type 3 LCF managed by CRPP or ORIF between 2018 and 2021. All patients were followed for at least 12 months. Patients were divided into two groups according to the type of treatment, CRPP or ORIF. Demographic characteristics were recorded for all patients. Standard radiographs were used to identify, evaluate, and classify each fracture and to detect the presence of other concomitant bone lesions. The clinical outcome was assessed according to the Hardacre et al. criteria.Seventy-eight children with type 3 LCF were included; 42 were treated by CRPP (53.8%) and 36 by ORIF (46.2%); the mean follow-up time was 17.7 months (range, 12.3-40.9). The baseline characteristics did not differ between the two groups of patients. Overall, successful CRPP could be achieved in 39 out of 42 patients (92.9%). The mean surgical time was 63.4 and 84.5 min in patients treated by CRPP and ORIF, respectively (p = 0.01). Fluoroscopy time was significantly shorter in patients managed by ORIF than in those treated by CRPP (12 versus 40 s, respectively; p 0.001). Clinical outcome according to the Hardacre et al. criteria was excellent in 37 out of 39 (94.4%) and in 35 out of 36 patients (97.2%) treated by CRPP and ORIF, respectively (p = 0.09).CRPP management of paediatric type 3 LCF has clinical and radiographic outcomes similar to ORIF; if satisfactory reduction cannot be achieved by CRPP, conversion to ORIF should be considered.

This paper is devoted to introducing a new implicit iterative algorithm based on viscosity approximation method and hybrid steepest-descent iterative method for finding the common fixed points set of a finite family of non-expansive mappings in Hilbert spaces. We certify that the sequences generated by this new implicit rule strongly converges to the unique solution of a class of variational inequalities under some suitable conditions of the parameters. The result extends and improves the corresponding results announced by many others. Moreover, applications to a broader family of λ-strictly pseudo-contractive mappings and generalized equilibrium problems. Finally, numerical results are given to clarify the effectiveness and practicability of the proposed algorithm, which compares with the iterative scheme of Cai and Shehu. Mathematics Subject Classification (2010). 47H10, 47J25, 49J40.

Purpose: To investigate the value of antero-posterior and lateral radiographs in predicting clubfoot relapse after treatment with the Ponseti method. Methods: This was a retrospective review of 104 children (157 feet) younger than 3 months of age with idiopathic clubfoot treated using the Ponseti method at our institution between January 2007 and December 2014. All patients underwent Achilles tenotomy and were divided into two groups according to the need for further surgery to correct the deformity: relapsed group (24 patients; 36 feet) and non-relapsed group (80 patients; 121 feet). All antero-posterior and lateral foot radiographs were performed less than 3 months after Achilles tenotomy. The talo-calcaneal (TC-AP) and talus-first metatarsal (TM-AP) angles were measured in the antero-posterior view, while the tibio-calcaneal (TIC-L), talus-first metatarsal (TM-L), and talo-calcaneal (TC-L) angles were measured in the lateral view. The multi-factor logistic regression model of the stepwise selection method was used to predict the relapse of clubfoot deformity from the potential predictive values. Results: The mean age at initial plain radiography examination was 99.45 ± 21.54 days. Differences in TC-AP, TM-AP, TC-L, and TIC-L between the two groups were statistically significant. However, only TM-AP and TIC-L were included in the “ risk of relapse” formula using the multi-factor logistic stepwise selection method. Conclusion: Early antero-posterior and lateral radiographs in children younger than 3 months of age at initial Ponseti treatment have positive predictive value for relapse. Reduced TM-AP angle and increased TIC-L were associated with an increased risk of relapse. Level of evidence: level III.

The aim of this study was to evaluate the characteristics of paediatric hand fractures (PHF) at a tertiary hospital in South China based on sex, age, mechanism of injury and anatomical region. A retrospective observational study was performed on children aged 15 years and younger who were referred for actual or suspected hand fractures between January 2016 and December 2020. Medical records and radiographs were reviewed for age at the time of injury, sex, site and fracture pattern and mechanism of injury. A total of 436 consecutive children with 478 hand fractures were reviewed. Hand fractures was more common in boys (281/436; 64.4%) than in girls (155/436; 35.6%), although most fractures occurred in children aged 0-3 years (198/436; 45.4%). Distal phalanges were the most commonly injured bones (184/478; 38.5%), and the base fractures were most common (151/476; 31.7%); the fifth digit was most commonly injured (150/478; 31.3%). Crush injuries were the leading cause of fracture in children younger than 6 years of age (207/325; 63.7%), whereas punch injuries were the major cause of injury in older age groups (55/153; 35.9%); 60.1% of the fractures were managed nonsurgically. This study showed patterns of PHF in a tertiary hospital in South China. It illustrates the local variability across sex, age group, injury type and injury mechanism. Such demographic data will be valuable for optimally resourcing healthcare systems locally and help guide prevention policies.

Purpose To investigate the success rate of the Tübingen hip flexion splint (THFS) for the treatment of developmental dysplasia of the hip (DDH), of different severity as per the Graf classification, among infants younger than six months of age. The type and incidence rate of complications associated with THFS treatment were also evaluated. Methods The following databases were searched using keywords and limited for age less than six months: PubMed, Embase, Web of Science, Cochrane Library, and SinoMed, between inception and July 2020. Articles were screened and extracted by two researchers, and the quality of the included literature was evaluated (methodological index for non-randomized studies criteria). R studio 1.3 was used for statistical analysis. The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Results After screening, eight articles were included in the analysis, contributing 1211 hips (875 patients). The overall success rate of THFS treatment is 91% (95% confidence interval (CI) 0.82 to 0.95). The success rate by Graf type is as follows: type-II, 98% (95% CI 0.94 to 1.00); type-III, 96% (95% CI 0.88 to 1.00); and type-IV, 32% (95% CI 0.18 to 0.47). Complications (24/1211, 2%) included transient femoral nerve palsy (n = 1); avascular necrosis of the femoral head (n = 9) and residual acetabular dysplasia (n = 14). Conclusion THFS treatment is successful for Graf type-II and –III, but low for type-IV, with a low rate of complication. THFS may be an effective treatment option for DDH among infants less than six months of age. However, those with Graf type-IV require close monitoring. Level of Evidence III

There is a paucity of data describing sagittal alignment changes in children with congenital scoliosis (CS) treated by hemivertebra (HV) resection. This study aimed to evaluate the effects of posterior HV resection on spine sagittal alignment in children with CS. This is a retrospective analysis of 31 children with CS (mean age at surgery: 49.61 ± 10.21 months; range, 39-72; mean follow-up time: 5.16 ± 1.21 years; range: 3-7) treated at our Institution. Only patients with single thoracic or single lumbar, fully segmented HV managed by posterior HV resection and two segments fusion with four screws and two robs were included. According to the anatomical location of the HV, patients were divided into two groups: thoracic (group A) and lumbar (group B). Thoracic kyphosis (T1-T12; TK) and lumbar lordosis (L1-S1; LL) were measured pre- and postoperatively at 6 months interval. Postoperative TK and LL were 30.3 ± 11.47 and 28.8 ± 9.47, and were 31.98 ± 9.66 and 46.7 ± 11.37 at the last follow-up visit, respectively. The incidence of thoracic hypokyphosis in group B was 53.3%, and it was significantly higher compared to group A (12.5%, P = 0.04). During follow-up, TK changes were comparable between the two groups of patients while LL improved in all patients 6 months after surgery, and continued to improve thereafter. Posterior HV resection and short segment fusion have limited impact on the evolution of TK; in particular, children with lumbar HV were more likely to be hypokyphotic preoperatively, but less likely postoperatively with an increase in LL and a stabilization of TK.

The objectives of this study were to (1) evaluate the radiographic characteristics of children with congenital thumb duplication (CTD) seen in our institution between August 2015 and April 2021; (2) introduce a modified radiographic classification system (MCS) capable of including all cases of CTD based on their radiographic pathoanatomy; and (3) evaluate the inter- and intrarater reliability of the new classification system.We retrospectively reviewed 2,108 patients with 2,300 CTDs. The MCS is based on the Wassel-Flatt and Chung et al classification systems and includes specific subtypes from the Rotterdam and modified Wassel-Flatt classifications. The MCS is characterized by 4 groups according to the anatomical morphology of the duplication: A (joint), B (epiphysis), C (bone), and D (soft tissues). Each group includes 4 subtypes according to the location of the CTD, with subtypes 1-3 extending from the distal phalanx to the metacarpal or interphalangeal joints, then to the carpometacarpal joint, and with subtype 4 only including the triphalangia of the main thumb.Among the 2,300 fingers, 360 (15.7%), 2 (0.1%), and 3 (0.1%) CTDs could not be classified according to the Wassel-Flatt, Chung et al, and Rotterdam classifications, respectively. According to the MCS, the 2 most common forms of CTD were A2 (680/2,300; 29.6%) and D2 (308/2,300; 13.4%). All cases could be classified according to this classification system. The MCS showed excellent intrarater (0.875) and interrater (0.851) reliability relative to the Wassel-Flatt (0.863 and 0.820, respectively), Chung et al (0.793 and 0.822, respectively), and Rotterdam (0.873 and 0.836, respectively) systems.The MCS is a potential radiographic classification for CTD that enables the classification of all patients and has excellent inter- and intrarater reliability.Existing classification systems do not allow classification of the full spectrum of CTD and are not always related to surgery, and some existing systems are complex, with many categories that are rarely encountered, or are difficult to use widely in clinical practice.

Some patients with developmental dysplasia of the hip (DDH) before 6 months of age successfully treated by Pavlik Harness (PH) still had persistent acetabular dysplasia (PAD). This study aimed to investigate the incidence and risk factors for PAD in patients with DDH treated by PH. We retrospectively reviewed the data of 89 patients (109 hips; mean age, 3.2 ± 1.5 months) with DDH treated by PH. Prior to treatment, all patients underwent ultrasound examination and classified according to Graf's method. PH was terminated once the hip achieved imaging recovery criteria. At final follow-up, the acetabular index (AI), center-edge angle (CEA) of Wiberg were measured on radiograph. Overall, 67/109 hips (61.5%) had successful PH treatment. Among these 67 hips, 58 hips (86.6%) achieved satisfactory outcome, nine (13.4%) had PAD. Age of the patients with PAD (4.3 ± 1 months) was significantly higher than those without PAD (2.8 ± 1.5 months) (P = 0.001). Hips with PAD had higher mean Graf grade than those with satisfactory outcome (P = 0.014). Logistic regression-confirmed age and Graf classification were risk factors for PAD. Overall, 55/67 (82.1%) met imaging recovery criteria to stop PH treatment, whereas 12/67 hips (17.9%) did not. The rate of PAD at final follow-up in patients achieving recovery criteria (4/55; 7.3%) was significantly lower than those not achieving it (41.7%) (P = 0.007). In conclusion, age and Graf classification are risk factors for PAD. If hips are not normal at the end of PH treatment, the risk of PAD increases further.

Background: Idiopathic congenital talipes equinovarus (ICTEV) is one of the most common congenital deformities of children, and dysplasia of the striated muscle may be one of the causes of ICTEV. P...

Open reduction with or without pelvic and femoral osteotomy is the accepted treatment option for children older than 18 months with developmental dislocation of the hip (DDH). However, few studies have investigated hip function in children with late DDH treated by open reduction. Therefore, we performed a retrospective study investigating the risk factors potentially associated with unsatisfactory hip function.We hypothesized that some risk factors can be associated with unsatisfactory hip function in patients with late DDH treated by open reduction.We retrospectively reviewed the clinical and radiographic data of 79 children (98 hips, mean age 39.7±18.6 months; range, 19-95.3) with late-detected DDH treated by open reduction. Acetabular index (AI), Tönnis grade, Center Edge Angle (CEA), avascular necrosis of the femoral epiphysis (AVN), and Severin radiographic grade were evaluated on radiographs. Hip function was rated according to modified Outcome Evaluation Standard for Congenital Dislocation of the Hip with a maximum score of 15. According to type of surgery, patients were divided into four groups: open reduction alone (Group A), open reduction in conjunction with pelvic osteotomy (Group B), and open reduction in conjunction with femoral osteotomy and Pemberton/Salter (Group C) or Bernese-type triple pelvic osteotomy (Group D). Analysis of variance (ANOVA), t-test, chi-square test, and multivariate regression analysis were used to evaluate the independent risk factors of unsatisfactory hip function.The mean hip function score was 10.8±2.8 (4.5-15); 61 hips (62.2%) had satisfactory function (23 [23.5%] excellent and 38 [38.8%] good), while 37 hips (37.8%) had unsatisfactory function (16 [16.3%] fair and 21 [21.4%] poor). Spearman correlation analysis indicated that age at surgery was negatively correlated with function score (r=-0.326, p=0.001). The age of patients with satisfactory hip function (34.5±14.2 months; range, 19.4-74.8) was significantly lower than those with unsatisfactory function (43.7±21 months; range, 20.6-95.3) (p=0.011). The hip function score in Group A (14.2±0.8; range, 12.8-15) was significantly higher than in the other three groups (p0.001). Hip function score in patients with type III or IV AVN was significantly lower than those without AVN, or with type II AVN (p=0.001). Multivariate regression analysis confirmed age at surgery, type of surgery and AVN were negatively correlated with hip function score. Logistic regression analysis and chi-square test confirmed age and type of surgery, and AVN were independent risk factors of unsatisfactory hip function. Multivariate regression analysis found ability to squat and amount of hip flexion and abduction, significantly decreased with age at surgery; while presence of limping, amount of hip flexion, abduction, adduction and external rotation significantly decreased with type of surgery.Age at surgery, type of surgery and severe AVN are independent risk factors for unsatisfactory hip function in patients with late-detected DDH treated by open reduction. The ability to squat, the amount of hip flexion and abduction are the main functional parameters affected by age and surgery.IV, case series.

Aims This study aimed to investigate the effect of solute carrier family 20 member 2 ( SLC20A2) gene mutation (identified from a hereditary multiple exostoses family) on chondrocyte proliferation and differentiation. Methods ATDC5 chondrocytes were cultured in insulin-transferrin-selenium medium to induce differentiation. Cells were transfected with pcDNA3.0 plasmids with either a wild-type (WT) or mutated (MUT) SLC20A2 gene. The inorganic phosphate (Pi) concentration in the medium of cells was determined. The expression of markers of chondrocyte proliferation and differentiation, the Indian hedgehog (Ihh), and parathyroid hormone-related protein (PTHrP) pathway were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Results The expression of SLC20A2 in MUT group was similar to WT group. The Pi concentration in the medium of cells in MUT group was significantly higher than WT group, which meant the SLC20A2 mutation inhibited Pi uptake in ATDC5 chondrocytes. The proliferation rate of ATDC5 chondrocytes in MUT group was greater than WT group. The expression of aggrecan (Acan), α-1 chain of type II collagen (COL2A1), and SRY-box transcription factor 9 (SOX9) were higher in MUT group than WT group. However, the expression of Runt-related transcription factor 2 (Runx2), α-1 chain of type X collagen (COL10A1), and matrix metallopeptidase 13 (MMP13) was significantly decreased in the MUT group. Similar results were obtained by Alcian blue and Alizarin red staining. The expression of Ihh and PTHrP in MUT group was higher than WT group. An inhibitor (cyclopamine) of Ihh/PTHrP signalling pathway inhibited the proliferation and restored the differentiation of chondrocytes in MUT group. Conclusion A mutation in SLC20A2 (c.C1948T) decreases Pi uptake in ATDC5 chondrocytes. SLC20A2 mutation promotes chondrocyte proliferation while inhibiting chondrocyte differentiation. The Ihh/PTHrP signalling pathway may play an important role in this process. Cite this article: Bone Joint Res 2020;9(11):751–760.

Purpose The objective of this study was to explore the predictors for failed reduction in children with developmental dysplasia of the hip (DDH) managed by arthrogram, closed reduction (CR) and spica cast immobilization. Methods We retrospectively reviewed the clinical data of patients with DDH treated by CR and cast immobilization (2015-2020), including age, sex, affected side, presence/absence of an ossific nucleus, International Hip Dysplasia Institute classification, the delineation of labrum and acetabular surface on arthrogram, inverted labrum, acetabular index (AI), hip abduction angle and medial dye pool (MDP) distance. Predictors that potentially predicted failure of CR were evaluated by logistic regression analysis, simple t-test, Fisher's Exact Test and chi-square test. Results In total, 16 out of 187 hips failed to achieve initial CR (8.6%). Gender, age, preoperative AI and poor delineation of arthrogram were candidate predictors for failed CR in children aged six to 24 months with DDH; on the other hand, logistic regression analysis confirmed age and poor delineation of arthrogram significantly predicted failure of CR. Receive operating characteristic curve (ROC) showed MDP less than 6 mm and age higher than 14.5 months significantly increased the failure rate of CR in children aged six to 24 months with DDH. Conclusion Age and poor delineation of labrum and acetabular surface during arthrogram predicted failure of CR in children with DDH. In particular, age > 14.5 months and MDP distance ≥ 6 mm significantly increased the risk of CR failure. Level of evidence III

To retrospectively evaluate the clinical and radiographic outcomes of fractures of the base of the proximal phalanx (FBPP) in children by closed reduction and cast immobilization (CRCI) and closed reduction and percutaneous pinning (CRPP). Thirty-four consecutive children with FBPP were treated by CRCI (group A) and CRPP (group B). The diaphyseal axis-metacarpal head angle (DHA) was measured in anteroposterior radiographs before and after treatment. At the last follow-up visit, the range of motion of the injured finger was evaluated by the Total Active Flexion Scale. One year and more after the index procedure, patients were asked to answer the Michigan Hand Outcomes Questionnaire (MHQ). Fifteen patients (44.1%) were in group A and 19 (55.9%) in group B. groups A and B did not differ significantly in their demographics and preoperative DHA (P > 0.05). However, the postoperative DHA improved significantly after treatment, whether group A (P < 0.001) or group B (P < 0.001). And nonoperative treatment yielded a better DHA than surgical treatment (P = 0.01). Overall, five in group A (20%) and two in group B (37%) (P = 0.06) developed a complication. The mean MHQ score was 97.2 ± 5.3 (range, 78.1-100) and 99.3 ± 2.0 (range, 92.8-100) in groups A and B, respectively (P = 0.15). Children with isolated, displaced FBPP treated conservatively can achieve similar clinical and radiological outcomes, and lower complication rates, compared to patients managed surgically; however, fracture more severely displaced initially may have higher rates of complications after surgical fixation. If conservative treatment fails, surgery is recommended.

This study aims to evaluate (1) the probability to achieve normal pelvic radiographs in children with developmental dysplasia of the hip (DDH) treated by closed reduction and (2) the amount of time needed to achieve normal pelvic radiographs and to assess what factors influence both probability and time to achieve normal radiographic parameters following CR and spica cast immobilization for DDH. We retrospectively reviewed 436 patients (393 girls, 43 boys; 507 hips) with DDH treated by closed reduction (CR). Tonnis grade, AVN, acetabular index (AI), centre-edge angle (CEA), and Severin radiographic grade were evaluated on plain radiographs. Criteria to rate pelvis radiographs as normal were established. Cox regression was used to evaluate the factors influencing the probability and the time to achieve normal radiographs. According to our criteria, 167 hips (32.9%) achieved normal radiographic parameters during follow-up. The overall amount of time to achieve normal pelvis radiographs was 36.1 ± 15.5 months. Patients older than 24 months of age at the time of CR needed longer time to achieve normal radiographic parameters (55.2 ± 28 months) compared with other age groups. Cox regression analysis suggested the overall cumulative probability of recovery increased by 46% at five years following CR, then it tended to plateau with an annual increase less than 5%. Age older than 24 months, bilateral dislocation, pre-operative AI greater than 40°, and AVN were risk factors for reduced probability of achieving normal radiographic parameters. The cumulative probability of achieving normal pelvis radiographs increases linearly during the first five years following CR, then it tends to plateau. Age older than 24 months and Tonnis grade III and IV are associated with longer time to achieve normal radiographic parameters. Age older than 24 months, bilateral dislocation, pre-operative AI greater than 40°, and AVN are risk factors for reduced probability of achieving normal radiographic parameters in children with DDH treated by closed means.

Purpose The purpose of this study was to identify if any correlation between size of the proximal femoral epiphysis and avascular necrosis (AVN) exists. Methods We retrospectively reviewed 111 patients with developmental dysplasia of the hip treated by closed reduction (124 hips). The diameter and height of both femoral head and ossific nucleus were assessed on preoperative MRI. Results The diameter and the height of the femoral head as well as of the ossific nucleus of the contralateral side were significantly greater than the dislocated side. AVN occurred in 21 (16.9%) out of 124 hips. The rate of AVN gradually decreased with age: 30.0% at six to 12 months, 18.2% at 12 to 18 months and 3.7% at 18 to 24 months. Spearman correlation analysis showed that age is negatively correlated with the incidence of AVN (r = -0.274; p = 0.002) and the diameter of the femoral head has a significantly negative association with the incidence of AVN (r = -0.287; p = 0.001). No significant association was observed between the incidence of AVN and height of the femoral head or size of the ossific nucleus. Hips with AVN were significantly smaller than hips without AVN. Conclusions The size of both the femoral head and the ossific nucleus increase with age although the dislocated femoral head is smaller compared with the contralateral side. The diameter of the femoral head and not the size of the ossific nucleus negatively correlate with the risk of AVN, with a bigger femoral head showing lower risk of AVN. Level of evidence III

Background: Percutaneous Achilles tenotomy (PAT) is an important component of the Ponseti method and is performed in 85% to 90% of patients. However, there is a lack of objective data assessing early radiographic changes in children undergoing PAT. Methods: Forty-nine patients with idiopathic clubfoot treated by Ponseti casting were prospectively enrolled between October 2017 and October 2018. Preoperative and postoperative ankle dorsiflexion (pre-ADFmax, post-ADFmax) and lateral talocalcaneal angle (pre-LTCAmax, post-LTCAmax) values with the ankle in maximal dorsiflexion as well as postoperative LTCA values with the ankle in the neutral position (post-LTCAneutral) were measured. The relationship between the preoperative and postoperative ADF and LTCA values was studied using Pearson or Spearman correlation coefficients. Forty-nine patients (72 feet) were included; the mean age at initial treatment was 32.2 ± 24.1 days. Results: Post-LTCAmax improved significantly from 18.6 ± 9.2 degrees to 25.1 ± 10.5 degrees ( P < .0001). Pre-ADF and pre-LTCAmax showed a positive correlation in both the less than 28-day group ( r = 0.42; P = .015) and the Dimeglio III group ( r = 0.29; P = .035). However, post-ADF and post-LTCAmax showed a positive correlation in the Dimeglio III group ( r = 0.30; P = .028). The degree of improvement in post-LCTAmax in the Dimeglio III group was similar to that in the Dimeglio IV group ( P = .28). Conclusion: The LTCA increased immediately after PAT in clubfoot, although the improvement seemed to be unrelated to the severity of the disease. PAT led to an increase in both ADF and the LTCA, and it contributed to the improvements in subtalar joint motion and alignment. Level of Evidence: Level III, comparative study.

This study was aimed to evaluate the kinetics and kinematics of the foot and ankle using three-dimensional gait analysis in children with recurrent clubfoot treated with tibialis anterior tendon transfer (TATT). Three-dimensional gait analysis of 17 children with dynamic supination (24 feet; 12 males; mean age: 6.34 years) was performed pre- and post-TATT. Spatial, temporal and kinematic parameters, as well as the gait deviation index (GDI), were recorded for all patients. Moreover, to evaluate the severity of dynamic supination during walking, we also measured the angle between the plane of the foot and the X-axis during the swing phase (V-angle-S). The postoperative step length (38.95 ± 8.36 cm) and stride length (76.73 ± 15.92 cm) were significantly smaller than their preoperative values (40.68 ± 9.35 cm and 80.57 ± 17.51 cm; P = 0.0316 and P = 0.0028, respectively). The postoperative peak internal ankle rotation angle in the frontal plane (20.45° ± 14.44) was significantly lower than the preoperative value (25.93° ± 9.84; P = 0.029). The postoperative peak internal foot progression angle in the transverse plane (0.96° ± 5.83) was significantly lower than the preoperative value (4.34° ± 8.88; P = 0.026). However, both the peak ankle varus moment and GDI were not significantly different between the pre- and postoperative data. Postoperative V-angle-S values (28.55° ± 7.56) were reduced compared to their preoperative values (32.52° ± 6.53; P = 0.0094). TATT to the lateral cuneiform can correct dynamic supination in patients with a recurrent clubfoot; however, it has limited or no effects on hindfoot varus deformity. Level of evidence: Level III.

BACKGROUND To compare the effects of two types of cast immobilization (human position cast and dynamic cast) on hip development in children with Developmental dysplasia of the hip (DDH) after closed reduction (CR). METHODS A retrospective study of 60 children (64 hips) with DDH who underwent CR and cast immobilization between January 2015 and December 2016 at our Institution was performed. The average age at the time of CR was 14.6 months (range, 6.1-23.5). Fifty-seven females and 3 males were included. According to the technique of cast immobilization, two groups of patients could be identified: patients with DDH managed by human position cast immobilization (Group A: 32 patients, 34 hips) and patients with DDH treated by dynamic cast immobilization (Group B: 28 patients, 30 hips). Hip joint distance (HJD) after CR was measured on MRI. Acetabular index (AI) and Acetabular Depth Radio (ADR) were measured of anterior-posterior (AP) radiographs before and 3 months after CR; AI and central edge angle (CEA) were measured last follow-up AP radiographs. The presence of subluxation or dislocation and avascular necrosis (AVN) at the last follow-up visit was also evaluated. RESULTS The patients were comparable regarding to sex, side, age, Tonnis degree, AI, and ADR before the reduction between two groups. There was no significant difference in HJD improvement between the two groups 6 weeks following closed reduction. The AI(27.5±5.1°) of group B was significantly lower than those of Group A (31±4.9°) (p=0.03) when cast was removed 3 months after CR. At the last follow-up, the incidence of AVN was similar between the two groups of patients (Group A: 11.8% versus Group B: 13.3%), and the incidence of subluxation or dislocation (Group A: 8.8% versus Group B: 10%). At last follow-up visit, the AI (23.7±5.4°) in Group B was significantly lower than in Group A (26.9±4.1°) (p=0.02). CONCLUSIONS Dynamic cast immobilization promotes acetabular development following CR in patients aged 6 to 24 months with DDH. Dynamic cast immobilization does not increase the risk of dislocation or subluxation, nor of AVN.

Neurofibromatosis type I (NF1) is an autosomal dominant genetic disease that is caused by mutations in the NF1 gene. Various studies have previously demonstrated that the mTOR complex 1 signaling pathway is essential for the NF1-modulated osteogenic differentiation of bone mesenchymal stem cells (BMSCs). Additionally, the mTOR signaling pathway plays a notable role in autophagy. The present study hypothesized that NF1 could modulate the osteogenic differentiation of BMSCs by regulating the autophagic activities of BMSCs. In the present study, human BMSCs were cultured in an osteogenic induction medium. The expression of the NF1 gene was either knocked down or overexpressed by transfection with a specific small interfering RNA (siRNA) targeting NF1 or the pcDNA3.0 NF1-overexpression plasmid, respectively. Autophagic activities of BMSCs (Beclin-1, P62, LC3B I, and LC3B II) were determined using western blotting, electron microscopy, acridine orange (AO) staining and autophagic flux/lysosomal detection by fluorescence microscopy. In addition, the autophagy activator rapamycin (RAPA) and inhibitor 3-methyladenine (3-MA) were used to investigate the effects of autophagy on NF1-modulated osteogenic differentiation in BMSCs. Inhibiting NF1 with siRNA significantly decreased the expression levels of autophagy markers Beclin-1 and LC3B-II, in addition to osteogenic differentiation markers osterix, runt-related transcription factor 2 and alkaline phosphatase. By contrast, overexpressing NF1 with pcDNA3.0 significantly increased their levels. Transmission electron microscopy, AO staining and autophagic flux/lysosomal detection assays revealed that the extent of autophagosome formation was significantly decreased in the NF1-siRNA group but significantly increased in the NF1-pcDNA3.0 group when compared with the NC-siRNA and pcDNA3.0 groups, respectively. In addition, the activity of the PI3K/AKT/mTOR pathway [phosphorylated (p)-PI3K, p-AKT, p-mTOR and p-p70S6 kinase] was significantly upregulated in the NF1-siRNA group compared with the NC-siRNA group, and significantly inhibited in the NF1-pcDNA3.0 group, compared with the pcDNA3.0 group. The knockdown effects of NF1-siRNA on the autophagy and osteogenic differentiation of BMSCs were reversed by the autophagy activator RAPA, while the overexpression effects of NF1-pcDNA3.0 on the autophagy and osteogenic differentiation of BMSCs were reversed by the autophagy inhibitor 3-MA. In conclusion, results from the present study suggest at the involvement of autophagy in the NF1-modulated osteogenic differentiation of BMSCs. Furthermore, NF1 may partially regulate the autophagic activity of BMSCs through the PI3K/AKT/mTOR signaling pathway.

Purpose The purpose of this study was to explore whether increasing the hip abduction angle would increase the incidence of avascular necrosis (AVN) in patients with late- detected developmental dysplasia of the hip (DDH) treated by closed reduction (CR) and spica cast immobilization. Methods A total of 55 patients (59 hips) with late-detected DDH underwent MRI after CR. Hip abduction angle and hip joint distance were measured on postoperative MRI transverse sections. The acetabular index and centre-edge angle were measured on plain radiographs at the last follow-up. The presence of AVN according to Kalamchi and McEwen's classification was assessed. We retrospectively analyzed the associations among abduction angles, hip joint distances, radiographic parameters, AVN and final outcomes, exploring the relationship between hip joint abduction angle and AVN rate. Results The mean age at the time of CR was 14.4 months SD 5.5 (6 to 28), and the mean follow-up was 26.2 months SD 8.1 (12.4 to 41.7). The mean hip abduction angle was 70.2° SD 7.2° (53° to 85°) on the dislocated side and 63.7° SD 8.8° (40° to 82°) on the normal side; the mean hip joint distance was 5.1 mm SD 1.9 (1.3 to 9.1) on the dislocated side and 2.2 mm SD 0.6 on the normal side (1.3 to 3.3). Eight of 59 hips (13.6%) developed AVN. Neither the amount of abduction nor hip joint distance increased the AVN rate (p = 0.97 and p = 0.65, respectively) or the dislocation rate (p = 0.38 and p = 0.14, respectively). Conclusion Abduction angle up to 70.2° following CR did not increase the AVN rate in children aged six to 28 months with late-detected DDH treated by CR. Level of evidence III.