Definition of the Post-COVID syndrome using a symptom-based Post-COVID score in a prospective, multi-center, cross-sectoral cohort of the German National Pandemic Cohort Network (NAPKON).

PURPOSE: The objective examination of the Post-COVID syndrome (PCS) remains difficult due to heterogeneous definitions and clinical phenotypes. The aim of the study was to verify the functionality and correlates of a recently developed PCS score. METHODS: The PCS score was applied to the prospective, multi-center cross-sectoral cohort (in- and outpatients with SARS-CoV-2 infection) of the "National Pandemic Cohort Network (NAPKON, Germany)". Symptom assessment and patient-reported outcome measure questionnaires were analyzed at 3 and 12 months (3/12MFU) after diagnosis. Scores indicative of PCS severity were compared and correlated to demographic and clinical characteristics as well as quality of life (QoL, EQ-5D-5L). RESULTS: Six hundred three patients (mean 54.0 years, 60.6% male, 82.0% hospitalized) were included. Among those, 35.7% (215) had no and 64.3% (388) had mild, moderate, or severe PCS. PCS severity groups differed considering sex and pre-existing respiratory diseases. 3MFU PCS worsened with clinical severity of acute infection (p = .011), and number of comorbidities (p = .004). PCS severity was associated with poor QoL at the 3MFU and 12MFU (p < .001). CONCLUSION: The PCS score correlated with patients' QoL and demonstrated to be instructive for clinical characterization and stratification across health care settings. Further studies should critically address the high prevalence, clinical relevance, and the role of comorbidities. TRAIL REGISTRATION NUMBER: The cohort is registered at www. CLINICALTRIALS: gov under NCT04768998.

Do's and Don'ts in Primary Aneurysmal Bone Cysts of the Proximal Femur in Children and Adolescents: Retrospective Multicenter EPOS Study of 79 Patients.

BACKGROUND: Aneurysmal bone cysts (ABC) are rare benign cystic bone tumors, generally diagnosed in children and adolescents. Proximal femoral ABCs may require specific treatment strategies because of an increased pathologic fracture risk. As few reports are published on ABCs, specifically for this localization, consensus regarding optimal treatment is lacking. We present a large retrospective study on the treatment of pediatric proximal femoral ABCs. METHODS: All eligible pediatric patients with proximal femoral ABC were included, from 11 tertiary referral centers for musculo-skeletal oncology (2000-2021). Patient demographics, diagnostics, treatments, and complications were evaluated. Index procedures were categorized as percutaneous/open procedures and osteosynthesis alone. Primary outcomes were: time until full weight-bearing and failure-free survival. Failure was defined as open procedure after primary surgery, >3 percutaneous procedures, recurrence, and/or fracture. Risk factors for failure were evaluated. RESULTS: Seventy-nine patients with ABC were included [mean age, 10.2 (±SD4.0) y, n=56 male]. The median follow-up was 5.1 years (interquartile ranges=2.5 to 8.8).Index procedure was percutaneous procedure (n=22), open procedure (n=35), or osteosynthesis alone (n=22). The median time until full weight-bearing was 13 weeks [95% confidence interval (CI)=7.9-18.1] for open procedures, 9 weeks (95% CI=1.4-16.6) for percutaneous, and 6 weeks (95% CI=4.3-7.7) for osteosynthesis alone ( P =0.1). Failure rates were 41%, 43%, and 36%, respectively. Overall, 2 and 5-year failure-free survival was 69.6% (95% CI=59.2-80.0) and 54.5% (95% CI=41.6-67.4), respectively. Risk factors associated with failure were age younger than 10 years [hazard ratios (HR)=2.9, 95% CI=1.4-5.8], cyst volume >55 cm 3 (HR=1.7, 95% CI=0.8-2.5), and fracture at diagnosis (HR=1.4, 95% CI=0.7-3.3). CONCLUSIONS: As both open and percutaneous procedures along with osteosynthesis alone seem viable treatment options in this weight-bearing location, optimal treatment for proximal femoral ABCs remains unclear. The aim of the treatment was to achieve local cyst control while minimizing complications and ensuring that children can continue their normal activities as soon as possible. A personalized balance should be maintained between undertreatment, with potentially higher risks of pathologic fractures, prolonged periods of partial weight-bearing, or recurrences, versus overtreatment with large surgical procedures, and associated risks. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Implementation of Copy Number Variations-Based Diagnostics in Morphologically Challenging EWSR1/FUS::NFATC2 Neoplasms of the Bone and Soft Tissue.

In the last decade, new tumor entities have been described, including EWSR1/FUS::NFATC2-rearranged neoplasms of different biologic behavior. To gain further insights into the behavior of these tumors, we analyzed a spectrum of EWSR1/FUS::NFATC2-rearranged neoplasms and discuss their key diagnostic and molecular features in relation to their prognosis. We report five patients with EWSR1/FUS::NFATC2-rearranged neoplasms, including one simple bone cyst (SBC), two complex cystic bone lesions lacking morphological characteristics of SBC, and two sarcomas. In three cases, fluorescence in situ hybridization (FISH) and in all cases copy number variation (CNV) profiling and fusion analyses were performed. All patients were male, three cystic lesions occurred in children (aged 10, 14, and 17 years), and two sarcomas in adults (69 and 39 years). Fusion analysis revealed two FUS::NFATC2 rearrangements in two cystic lesions and three EWSR1::NFATC2 rearrangements in one complex cystic lesion and two sarcomas. EWSR1 FISH revealed tumor cells with break-apart signal without amplification in one complex cystic lesion and EWSR1 amplification in both sarcomas was documented. CNV analysis showed simple karyotypes in all cystic lesions, while more complex karyotypes were found in NFATC2-rearranged sarcomas. Our study supports and expands previously reported molecular findings of EWSR1/FUS::NFATC2-rearranged neoplasms. The study highlights the importance of combining radiology and morphologic features with molecular aberrations. The use of additional molecular methods, such as CNV and FISH in the routine diagnostic workup, can be crucial in providing a correct diagnosis and avoiding overtreatment.

Long-term clinical and radiological outcomes following surgical treatment for symptomatic pediatric flexible flat feet: a systematic review.

BACKGROUND AND PURPOSE: Albeit pediatric flexible flat foot (FFF) is a common condition, only a minority of patients become symptomatic. Long-term outcomes of surgically treated pediatric patients with symptomatic FFF are largely unknown. In this systematic review, studies providing outcomes at a mean follow-up of at least 4 years after the procedure in these patients were analyzed. MATERIAL AND METHODS: A PubMed search was undertaken involving original articles published up to July 2021 on outcome in children aged 6 to 14 with surgically treated FFF and mean (or minimum) follow-up of at least 4 years. Radiographic and clinical outcomes were analyzed. RESULTS: Of initially 541 entries, 10 could be included in the systematic review (all level IV), involving 846 pediatric patients with 1,536 symptomatic FFF. Pooled mean radiological (n = 8) and clinical follow-up (n = 10) was 5.3 (range 0.5-15) and 7.0 (range 4.1-15) years, respectively. Surgical procedures included arthroereisis (n = 8), lateral column lengthening (n = 1), and Horseman procedure (n = 1). Overall relative frequency of implant-associated complications and wound-healing problems was 3.2% and 1.3%, as well as 2.8% and 1.6% following subtalar arthroereisis only. From preoperative to latest radiological assessment following subtalar arthroereisis (including 3 studies with radiological follow-up < 48 months), pooled median decrease in talonavicular coverage angle (TNCA; -9.2°), anteroposterior talocalcaneal angle (A-TCA; -6.5°), lateral talocalcaneal angle (L-TCA; -3.5°), talar declination angle (TDA; -14°), Moreau Costa Bertani angle (MCB; -13°), and talo-firstmetatarsal angle (L-T1MA; -10°) was observed, as was an increase in calcaneal pitch (4.5°). INTERPRETATION: In symptomatic pediatric FFF patients, surgery is associated with a manageable complication profile, and results in satisfactory long-term clinical as well as radiological outcome. Yet scientific evidence is low, warranting larger scaled studies in the future.

α-Synuclein in Plasma-Derived Extracellular Vesicles Is a Potential Biomarker of Parkinson's Disease.

BACKGROUND: Extracellular vesicles are small vesicles that are released from many cells, including neurons. α-Synuclein has recently been described in extracellular vesicles derived from the central nervous system and may contribute to the spreading of disease pathology in α-synuclein-related neurodegeneration. OBJECTIVES: We aimed to examine the potential diagnostic value of α-synuclein in plasma extracellular vesicles from patients with Parkinson's disease (PD). METHODS: Preanalytical variables were studied to establish an optimized assay for preparation of plasma extracellular vesicles and detection of extracellular vesicle-derived α-synuclein. Plasma samples were obtained from 2 independent cohorts. The Tübingen cohort contained 96 patients with PD, 50 patients with dementia with Lewy bodies, 50 patients with progressive supranuclear palsy (PSP), and 42 healthy controls; the Kassel cohort included 47 patients with PD, 43 patients with dementia with Lewy bodies, and 36 controls with secondary parkinsonian syndromes. Extracellular vesicles were prepared from total plasma by size exclusion chromatography and quantified by nanoparticle tracking analysis, α-synuclein content was measured by an electrochemiluminescence assay. RESULTS: α-Synuclein concentration in plasma extracellular vesicles provided the best discrimination between PD, dementia with Lewy bodies, PSP, and healthy controls, with an area under the curve of 0.804 (PD vs dementia with Lewy bodies), 0.815 (PD vs. PSP), and 0.769 (PD vs healthy controls) in the Tübingen cohort. Results were validated in the Kassel cohort. CONCLUSIONS: The concentration of α-synuclein in plasma extracellular vesicles may serve as a potential diagnostic biomarker for PD. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

International Interdisciplinary Consensus Meeting on the Evaluation of Developmental Dysplasia of the Hip.

In September 2018, an international meeting of doctors of various disciplines, with expertise in the detection and treatment of DDH, was held in Csolyospalos, Hungary. The aim was to achieve consensus on the detection and early treatment of the condition and to develop a standardized system of teaching and training for hip ultrasound. There was strong agreement that US screening is essential. Specifically the Graf technique was selected as the technique of choice. Universal US screening was strongly favored. Screening should be carried out as soon as possible, but not later than the sixth week of age. US screening is cost-effective, does not result in overtreatment, and contributes to a reduction of long-term consequences. The essential principle of treatment is timely application of a device to achieve reduction, retention and maturation, by holding the hips in flexion, and a safe degree of abduction. It was agreed that the effectiveness of any screening policy depends on the correct scanning technique. Therefore, standardization of teaching and training of the Graf technique is mandatory. A unified teaching policy and materials should be developed for this purpose. Certification, re-certification and audit were discussed. The group, which has been formalized as the International Interdisciplinary Consensus Committee On DDH Evaluation (ICODE), will continue to meet and work towards establishing international consensus on DDH, standardizing and developing teaching and training of the Graf technique for hip US, and maintaining standards for detection and management.

Surgical treatment of posterior cruciate ligament lesions does not cause growth disturbances in pediatric patients.

PURPOSE: The aim of the present study was to describe epidemiology, management and outcome of pediatric and adolescent patients with posterior cruciate ligament (PCL) injuries. METHODS: Sixteen patients of less than 18 years of age with 7 PCL avulsion fractures and 9 PCL tears were included over a 10-year period. Trauma mechanism, additional injuries and treatment methods were analyzed. Follow-up examination included range of motion and ability to perform squats. Pedi-IKDC and Lysholm score were obtained and posterior shift was measured in kneeling view radiographs and compared to the contralateral side. Patients were grouped into pediatric patients with open physes at the time surgery and adolescent patients with closing or closed physes. In case of open physes, growth disturbances were assessed. RESULTS: Six of the treated patients (median age 12.5 years, range 10-13) had open physes at time of surgery. Five of those sustained avulsion fractures and treatment consisted of open reduction and screw fixation in four cases and graft reconstruction in one case. One patient sustained a PCL tear and underwent graft reconstruction. Follow-up at a median of 71.5 months (range 62-100) did not reveal any growth disturbances. Median Pedi-IKDC was 71.9 (range 51.7-92.1), median Lysholm score was 81.5 (range 66-88) and median posterior shift difference was 2.5 mm (range 0-11). The remaining 10 patients (median age 16 years, range 14-17) had closing/closed physis at the time of operation. Two patients presented with avulsion fractures treated with open reduction and screw fixation and 8 patients sustained PCL tears treated with graft reconstruction. At a median follow-up of 69.5 months (range 11-112), median Pedi-IKDC was 86.8 (range 36.8-97.7), median Lysholm score was 84.0 (range 45-95) and median posterior shift difference was 4 mm (range 0-15). CONCLUSIONS: In our small number of pediatric patients with PCL injuries, open reduction and epiphyseal screw fixation of displaced avulsed fractures and steep tunnel drilling in case of PCL reconstruction did not cause growth disturbances. Nevertheless, long-term functional impairment should be expected and close follow-up has to be recommended. LEVEL OF EVIDENCE: Therapeutic, Level IV.

Outcome following excision of the radial head in children with open physes for impaired elbow motion.

BACKGROUND: Only few reports have described the outcome of pediatric patients following radial head resection. Therefore, the aim of the present study was to assess clinical and radiologic outcome of patients with open physes following resection of the radial head. MATERIALS AND METHODS: Skeletally immature patients treated with resection of the radial head were included. Range of motion (ROM) of the elbow joint was compared with preoperative values. Grip strength, pronation and supination strength, and carrier angle were compared with the unaffected side. Radiographs were assessed for signs of arthrosis, radial migration, and perifocal ossification. Disabilities of the Arm, Shoulder and Hand and Mayo Elbow Performance scores were obtained. RESULTS: The study included 7 patients (mean age, 11 years), 5 with post-traumatic and 2 with congenitally impaired elbow joint motion. Mean follow-up was 47 months. Pronation/supination ROM improved significantly (P = .018). Extension/flexion ROM did not improve significantly (P = .122). Although grip strength (P = .027) and pronation strength (P = .028) of the affected side were significantly lower compared with the contralateral side, supination strength did not differ significantly (P = .176). The carrying angle was increased in 3 patients. Significant radial migration occurred (mean, 3 mm; standard deviation [SD], 3 mm; P = .018). Arthrosis was found in 3 patients. The mean Disabilities of the Arm, Shoulder and Hand score was 16.1 (range 8.8-30.8; SD, 10.1) and mean Mayo Elbow Performance Score was 88 (range, 70-100; SD, 12). CONCLUSIONS: Radial head excision may be considered for selected patients with open physes in cases of severe impairment of pronation/supination. However, sequelae such as radial migration, arthrosis, and elevation of the carrying angle should be expected.

Medial patellofemoral ligament (MPFL) reconstruction in combination with a modified grammont technique leads to favorable mid-term results in adolescents with recurrent patellofemoral dislocations.

PURPOSE: The aim of the present study is to present the outcome of a cohort of adolescent patients with trochlear dysplasia and elevated tibial tuberosity trochlear groove (TTTG) distance suffering from recurrent patellar dislocation. Treatment consisted of medial patellofemoral ligament (MPFL) reconstruction and a modified Grammont procedure. METHODS: MRI examinations were obtained pre- and postoperatively. Trochlear dysplasia was classified according to Déjour, and TTTG was measured on MRI. The Tegner Activity Scale and the Kujala Knee Score were assessed preoperatively and at follow-up. The Kujala Knee score and the IKDC 2000 knee score were documented at follow-up (median 50, range 20-61 months; SD 16.6). RESULTS: Seven knees of six patients (median age 16.5 years, range 14-17 years) with trochlear dysplasia and elevated TTTG distance (median 17 mm, range 16.1-21.9 mm; SD 2.8) were treated. Trochlear dysplasia was classified as Déjour type A in 1, type B in 5, and type C in 1 knee. The Kujala Knee Score significantly increased from values of 55 (range 17-88; SD 25.9) to 94 (range 73-100; SD 9.1) at follow-up (p = 0.028). TAS improved from preoperative 2 (range 0-7; SD 2.5) to 5 (range 4-9; SD 1.8) at follow-up (p = 0.034). Median IKDC 2000 Knee Score at follow-up was 89 (range 61-100, SD 13.4). No re-dislocations were encountered. CONCLUSION: In selected adolescents with recurrent patellofemoral instability, MPFL reconstruction in combination with a modified Grammont technique yields excellent functional outcome and could, therefore, help to avoid major procedures, such as osteotomies. LEVEL OF EVIDENCE: Therapeutic, Level IV.

Balloon kyphoplasty and percutaneous fixation of lumbar fractures in pediatric patients.

PURPOSE: Type A fractures of the spine requiring operative stabilization are rare injuries in the pediatric population. Current reports have demonstrated the safety of the combination of balloon kyphoplasty and minimal invasive management of thoraco-lumbar fractures in adults. There is no information about the efficacy of this approach in managing pediatric vertebral fractures. METHODS: The aim of the present study was to report the outcome of a small series of children with A fractures of the lumbar spine treated with the combination of the abovementioned techniques. RESULTS: Three male patients without neurological deficits aged 11, 12 and 14 years were treated with fractures located at L1, L1/L2 and L2/L3, respectively. In total, six kyphoplasties were performed (monolateral in 4 vertebrae, bilateral in one vertebra). Neither cases of cement leakage nor intra- or postoperative complications were noted. Minimally invasive kyphoplasty and stabilization led to a significant improvement of the sagittal index of all five treated vertebrae which could be maintained at follow-up (14, 19 and 20 months postoperatively). CONCLUSION: This study is the first one to present an excellent outcome of children with type A fractures treated with a combination of balloon kyphoplasty and percutaneous stabilization.

The origin points of the knee collateral ligaments: an MRI study on paediatric patients during growth.

PURPOSE: Different femoral origins for both the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) have been reported in the growing skeleton (epiphyseal and metaphyseal). Knowledge about the exact attachment sites is mandatory for anatomically correct reconstruction. This study assesses the femoral origins of the knee collateral ligaments in skeletally immature individuals using magnetic resonance imaging (MRI). METHODS: MRIs of 336 knee joints (median age 15 years (range 2-18 years), m = 209 and f = 127) were retrospectively analysed to assess the distances between the femoral origins of the MCL and LCL to the distal femoral growth plate. In 175 patients, the body sizes were additionally retrieved from medical records. RESULTS: Both MCL and LCL ligament origins were invariably located on the epiphysis. Mean MCL origin-growth plate distance was 9.6 mm (SD 2.1 mm; range 2.2-13.6 mm) in boys and 8.6 mm (SD 1.5 mm; range 3.4-12.0 mm) in girls. Mean LCL origin-growth plate distance was 9.3 mm (SD 1.8 mm; range 4.3-13.0 mm) in boys and 8.2 mm (SD 1.5 mm; range 3.4-11.8 mm) in girls. The distance between the growth plate and both collateral ligaments as well as the length of the LCL correlated positively with patients' age and body size (MCL R(2) = 0.673 and 0.556, LCL R (2) = 0.734 and 0.645, LCL length R(2) = 0.589 and 0.741; all p < 0.001). CONCLUSIONS: During growth, the femoral origins of the MCL and the LCL are constantly located on the distal femoral epiphysis. There is a linear increase in the distances from the ligaments' origins to the growth plate according to age and body size. This new information may be of clinical importance for reconstructive surgery of the knee's collateral ligaments.

Judet type-IV radial neck fractures in children: Comparison of the outcome of fractures with and without bony contact.

Background and purpose - Heavily displaced radial neck fractures in children are sometimes associated with poor outcome. A substantial number of these fractures require open reduction. We hypothesized that Judet type-IV fractures with a completely displaced radial head would result in a worse outcome than radial neck fractures with remaining bony contact. Patients and methods - We analyzed 19 children (median age 9.7 (4-13) years) who were treated for Judet type-IV radial neck fractures between 2001 and 2014. The outcome was assessed at the latest outpatient visit using the Linscheid-Wheeler score at a median time of 3.5 (1-8) years after injury. The patients were assigned either to group A (9 fractures with remaining bony contact between the radial head and the radial neck) or to group B (10 fractures without any bony contact). Results - The 2 groups were similar concerning age and sex. The rate of additional injuries was higher in group B (7/10 vs. 1/9 in group A; p = 0.009). The rate of open reduction was higher in group B (5/10 vs. 0/9 in group A; p = 0.01). Poor outcome was more common in group B (4/10 vs. 0/9 in group A; p = 0.03). In group B, the proportion of children with poor outcome (almost half) was the same irrespective of whether open or closed reduction had been done. Interpretation - The main causes of unfavorable results of radial neck fracture in children appear to be related to the energy of the injury and the amount of displacement-and not to whether open reduction was used.

Diagnosis and treatment of apophyseal injuries of the pelvis in adolescents.

An avulsion fracture occurs when the growth plate of an apophysis is injured due to a sudden and forceful contraction of the attaching musculotendinous unit. Usually it is adolescents who sustain these injuries, and a significant male preponderance has been found. Even though apophyseal fractures have been described in a variety of locations, the apophyses of the pelvis and hip are more prone to these injuries. Due to their rarity, avulsion fractures of the pelvis are often misdiagnosed. Additionally, patients can present late, and other pathologies are suspected initially. In most acute cases conservative treatment is successful. However, some cases require operative intervention. To plan an optimal treatment regimen, it is important to be familiar with the typical pathomechanism, the typical clinical findings, and the most commonly applied imaging modalities of these injures. The present review analyzes the currently available literature on the most frequently encountered apophyseal injuries of the pelvis in adolescent patients. Some case examples are also presented.

Injuries in physically disabled children.

Disability is a condition or function that is judged to be significantly impairing relative to the usual standard of an individual or group. The spectrum of musculoskeletal disabilities in children is immense and varied. Musculoskeletal disabilities are congenital or acquired; they affect a child partially or generally and can occur as a permanent or transient disability.Although injuries still represent a major concern for children and adolescents worldwide, studies focusing on injuries in physically disabled children are lacking. To detect musculoskeletal injuries, radiographs are frequently required. In disabled children the radiographic findings can detect the skeletal injury but also can present special radiographic findings of the underlying disease.This review offers an overview of different musculoskeletal disabilities and their related injuries as well as characteristic findings on radiographs.

Treatment for ischial tuberosity avulsion fractures in adolescent athletes.

PURPOSE: Avulsion fractures of the ischial tuberosity are rare sports injuries typically occurring in young athletes. Their misdiagnosis may lead to chronic pain or disability. The aim of this study is to report a retrospective series of patients sustaining a fracture of the ischial tuberosity and to propose decision guidelines. METHODS: The mechanism of accident, the diagnostic management, the mode of treatment and outcome after avulsion fractures of the ischial tuberosity in adolescents were analysed. RESULTS: Thirteen patients (1 female and 12 males) with a median age of 15 years (range 13-16 years) with an avulsion fracture of the ischial tuberosity were included. Twelve of these patients suffered from sports injuries leading to the avulsion fracture. Five of our patients with a displacement of >15 mm were treated operatively. The outcome was excellent in cases of acute presentation and osteosynthesis. Eight patients were treated conservatively: four of them showed a displacement of <15 mm and had an excellent outcome; and the other four patients had a displacement of >15 mm. Two of those patients had excellent outcome with regular bone healing, the remaining two patients developed pseudarthrosis associated with a good outcome. CONCLUSION: The present paper shows that in patients with displacement of <15 mm, conservative treatment yields excellent results and early operative intervention should be considered in physically active patients with displacement of >15 mm.

Elastic stable intramedullary nailing versus Kirschner wire pinning: outcome of severely displaced proximal humeral fractures in juvenile patients.

BACKGROUND: Significantly displaced juvenile proximal humeral fractures (Neer-Horowitz type 3 and 4) usually require reduction and fixation. The most commonly used fixation methods are Kirschner wire (K-wire) pinning or retrograde elastic stable intramedullary nailing (ESIN). However, results comparing the long-term outcome of both methods are absent in the literature. The aim of this study was to provide an outcome comparison of both techniques. METHODS: Included were 40 patients treated between 1998 and 2008 and who had complete records concerning operation time, duration of hospital stay, and time until implant removal. The assessment of clinical (Disabilities of Arm, Shoulder and Hand [DASH] and Constant-Murley scores) and radiologic long-term outcome was possible in 31 patients (78%). Preoperative, postoperative and follow-up radiographs of these patients were evaluated for angular deformity, reduction, and remodeling. RESULTS: The mean follow-up of the 31 patients (16 ESIN; 15 K-wire) was 5.8 ± 3.6 (standard deviation) years. The operative time of the primary fixation procedure was shorter in the ESIN group (P < .001), but the hospital stay and the time until implant removal were significantly longer. No significant difference was seen between the groups at follow-up for the mean DASH (ESIN, 1.44; K-wire, 1.66) or Constant-Murley (ESIN, 89.5; K-wire, 92) scores. The neck-shaft angle was significantly improved by reduction in both groups (P < .001) and remained unchanged at follow-up. CONCLUSIONS: ESIN and K-wire pinning have a favorable and comparable functional outcome and therefore seem to be adequate methods for treating Neer-Horowitz type 3 and 4 proximal humeral fractures in juvenile patients. The initially achieved improvement of the neck-shaft angle can be maintained at long-term follow-up.

Cellular reactions to biodegradable magnesium alloys on human growth plate chondrocytes and osteoblasts.

PURPOSE: In recent decades operative fracture treatment using elastic stable intramedullary nails (ESINs) has mainly taken precedence over conservative alternatives in children. The development of biodegradable materials that could be used for ESINs would be a further step towards treatment improvement. Due to its mechanical and elastic properties, magnesium seems to be an ideal material for biodegradable implant application. The aim of this study was therefore to investigate the cellular reaction to biodegradable magnesium implants in vitro. METHODS: Primary human growth plate chondrocytes and MG63 osteoblasts were used for this study. Viability and metabolic activity in response to the eluate of a rapidly and a slower degrading magnesium alloy were investigated. Furthermore, changes in gene expression were assessed and live cell imaging was performed. RESULTS: A superior performance of the slower degrading WZ21 alloy's eluate was detected regarding cell viability and metabolic activity, cell proliferation and morphology. However, the ZX50 alloy's eluate induced a favourable up-regulation of osteogenic markers in MG63 osteoblasts. CONCLUSIONS: This study showed that magnesium alloys for use in biodegradable implant application are well tolerated in both osteoblasts and growth plate chondrocytes respectively.

As simple as it sounds? The treatment of simple bone cysts in the proximal femur in children and adolescents: Retrospective multicenter EPOS study of 74 patients.

Purpose: Simple bone cysts are among the most prevalent benign cystic tumor-like lesions in children. Proximal femoral simple bone cysts may require specific treatment because of increased fracture risk. With limited literature available on this specific localization, consensus regarding optimal treatment is lacking. We present a large international multicenter retrospective cohort study on proximal femoral simple bone cysts. Methods: All consecutive pediatric patients with proximal femoral simple bone cyst from 10 tertiary referral centers for musculoskeletal oncology were included (2000-2021). Demographics, primary treatment, complications, and re-operations were evaluated. Primary outcomes were time until full weight-bearing and failure-free survival. Results: Overall, 74 simple bone cyst patients were included (median age 9 years (range = 2-16), 56 (76%) male). Median follow-up was 2.9 years (range = 0.5-21). Index procedure was watchful waiting (n = 6), percutaneous procedure (n = 12), open procedure (n = 50), or osteosynthesis alone (n = 6). Median time until full weight-bearing was 8 weeks (95% confidence interval = 0.1-15.9) for watchful waiting, 9.5 (95% confidence interval = 3.7-15.3) for percutaneous procedure, 11 (95% confidence interval = -0.7 to 13.7) for open procedure, and 6.5 (95% confidence interval = 5.9-16.1) for osteosynthesis alone (p = 0.58). Failure rates were 33%, 58%, 29%, and 0%, respectively (p = 0.069). Overall failure-free survival at 1, 2, and 5 years was 77.8% (95% confidence interval = 68.2-87.4), 69.5% (95% confidence interval = 58.5-80.5), and 62.0% (95% confidence interval = 47.9-76.1), respectively. Conclusion: A preferred treatment for proximal femoral simple bone cysts remains unclear, with comparable failure rates and times until full weight-bearing. Watchful waiting may be successful in certain cases. If not feasible, osteosynthesis alone can be considered. Treatment goals should be cyst control, minimizing complications and swift return to normal activities. Therefore, an individualized balance should be made between undertreatment, with potentially higher complication risks versus overtreatment, resulting in possible larger interventions and accompanying complications. Level of evidence: Level IV, retrospective multicentre study.

Reconstruction of the sternoclavicular joint in active patients with the figure-of-eight technique using hamstrings.

BACKGROUND: Dislocations of the sternoclavicular joint are rare injuries caused by massive forces applied to the joint. A high rate of complications has been reported following this injury emphasizing the importance of an accurate diagnosis and therapy. METHODS: We report a series of patients with chronic anterior or posterior sternoclavicular instability treated with figure-of-eight gracilis- or semitendinosus-tendon reconstruction. Tendon grafts were collected from the patient's ipsilateral knee. Preoperative and postoperative DASH scores were compared to evaluate the outcome. RESULTS: Six patients (mean age, 22 years; range 15-46; male = 3; female = 3) were included. The patients sustained an isolated dislocation of the sternoclavicular joint resulting from a high-energy trauma. Anterior instability was observed in 3 patients, posterior instability in 2 patients and the remaining patient showed multidirectional instability. The mean time from injury to operation was 8 months (range, 4-33). The semitendinosus tendon was used in 4 patients, the gracilis tendon in 2 patients, respectively. Follow-up examination was after 22 months (range, 14-34). The DASH score improved from 54.3 points (range, 45.7-68.8) preoperatively to 28.8 points (range, 25.8-34.5) postoperatively. All patients returned to full activity without limitations including competitive contact sports. CONCLUSION: Stabilization of the sternoclavicular joint with the figure-of-eight technique seems to be a feasible alternative for young and active patients with remaining instability following conservative treatment.