Bone defects are serious abnormalities caused by accidental fractures, disease, or congenital defects that can severely impact a patient's quality of life. Gold standard traditional techniques, including autografts and allografts, are limited in their reparative ability, leading to advances in bone tissue engineering (BTE). Currently, biomaterials-based 3D implants have acquired a pivotal role in treating bone defects. Specifically, bioprinting with natural polymer-based bioinks has become a widely used method for repairing bone defects. Biopolymer-based composite bioink has attracted sustained interest in the field of BTE due to its ability to print and generate complex hierarchical architectures that mimic bone environments, thereby promoting osteogenic activity. Despite these advantages, there is still a lack of clear understanding of the limitations of natural hydrogel-based bioinks in terms of mechanical strength, printability, and in vivo performance. Here, the challenges associated with the development, printing, and applications of natural hydrogel-based bioinks in the field of BTE are discussed. The specific criteria of hydrogels for application in the repair of bone defects are discussed, including material and biological properties. The various printing techniques adopted for 3D printing of hydrogels are investigated, including extrusion-based, laser-based, and inkjet-based printing. The limitations of commonly used natural hydrogels are analyzed in both preclinical and clinical studies, particularly their poor mechanical properties, fast degradation, and limited ability to support bone formation in vivo. The review also assesses recent advances in the use of natural polymer-based bioinks in animal models and clinical scenarios. In conclusion, a mismatch between current bioink design and clinical requirements is defined and future directions are proposed to enhance translational potential, while summarizing the key advantages and drawbacks of natural hydrogel-based bioprinting for BTE.

BACKGROUND:Periacetabular osteotomy (PAO) is a common procedure for the treatment of symptomatic acetabular dysplasia in adolescent patients. Despite concerns regarding surgical outcomes and complications in patients with hypermobility spectrum disorders (HSD), the outcomes of PAO in such patients are not well documented. METHODS:We conducted a retrospective cohort review of patients who underwent PAO for the treatment of symptomatic acetabular dysplasia. Radiographic parameters including the lateral center edge angle of Wiberg (LCEA), medial center edge angle (MCEA), anterior wall index (AWI), posterior wall index (PWI), and Tönnis angle were measured. Patient-reported outcomes (PROs) were also collected. RESULTS:The mean duration of follow-up of non-HSD and HSD patients was 2.86 ± 0.73 years and 3.00 ± 1.11 years, respectively. No significant differences were found in mean age ( P = 0.289), sex, body mass index ( P = 0.125), laterality ( P = 0.192), or the duration of follow-up ( P = 0.636). Postoperatively, LCEA and AWI in patients with HSD were higher than those in non-HSD patients ( P = 0.002, P = 0.007, respectively). No notable differences were observed in Modified Harris Hip Score, Nonarthritic Hip Score, International Hip Outcome Tool, Hip Dysfunction and Osteoarthritis Outcome Score, or mean changes in PROs between the non-HSD and HSD groups at preoperative, 1-year postoperative, and most recent follow-up timepoints. However, patient-reported satisfaction with surgery in the HSD group (9.39 ± 1.04) was significantly higher than the non-HSD group (8.35 ± 1.95; P = 0.047). CONCLUSION:Patients with HSD exhibited similar outcomes to patients without HSD after PAO for symptomatic acetabular dysplasia. Postoperative AWI and LCEA were markedly greater in patients with HSD consistent with our technical bias toward increased correction in such hips, suggesting greater anterolateral coverage of the femoral head after PAO may be a promising strategy to achieve improved outcomes in patients with HSD.

INTRODUCTION:Osteochondral lesions of the femoral head in young patients are a rare but challenging clinical problem. Fresh osteochondral allograft (OCA) transplantation has been proposed as one potential treatment option that may improve function and delay hip arthroplasty. However, there is a paucity of published data. The purpose of this study was to assess allograft survivorship and patient-reported outcomes in patients undergoing OCA transplantation for osteochondral lesions of the femoral head. METHODS:Sixteen patients (16 hips) who underwent femoral head OCA transplantation for the treatment of avascular necrosis between 1985 and 2021 were included. Mean age was 21.0±10.1 years (range: 11.6 to 43.5 y) and 56% were male. Mean allograft diameter was 26.9±4.2 mm (range: 20 to 35 mm) and mean thickness was 10.2±3.2 mm (range: 5 to 15 mm). We evaluated the frequency and type of further surgery, Hip Disability and Osteoarthritis Outcome Score (HOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), modified Harris Hip Score (mHHS), and UCLA function score. Clinical failure was defined as conversion to total hip arthroplasty. RESULTS:Six of 16 hips (38%) experienced clinical failure (5 total hip arthroplasties and 1 resurfacing arthroplasty), with a mean time to failure of 3.6±2.6 years (range: 1.0 to 8.5 y). Allograft survivorship for patients under age 18 was 85.7% at 3 years and 42.9% at 5 years compared with patients over age 18 years who experienced a survivorship of 66.7% at 3 and 5 years ( P =0.911). Of the remaining 10 hips, the mean follow-up duration was 4.1 years (range: 1.9 to 7.4 y). At the latest follow-up, mean HOOS was 74.5±20.2 (range: 48.6 to 100), mean WOMAC was 79.9±18.2 (range: 56.1 to 100), mean mHHS was 74.9±20.9 (range: 41 to 100.1), and mean UCLA score was 7.0±2.7 (range: 4 to 10). CONCLUSIONS:Young patients with large chondral lesions of the femoral head may benefit from fresh OCA transplantation, but failure rates remain quite high for this challenging patient population. OCA can be considered as a useful treatment option that preserves function and delays the need for arthroplasty in young individuals with osteochondral lesions of the femoral head.

In modern civilization with fast work culture and uncontrolled lifestyles increase bone-related problems, moreover, lack of auto-regeneration of bone, indulge to formulate a suitable methodology to get rid of this problem. In this article, nanohydroxyapatite (nHA) decorated hierarchical titanium phosphate (TP) was synthesized by solvothermal process and incorporated into newly synthesized tartaric acid-based polyurethane (PU) through in situ technique. The porous 3D scaffold was fabricated by most advanced 3D printing technique with desired porous structure in a controlled manner. The biochemical properties of scaffold's surface were improved via immobilizing polydopamine (PDA) at ambient temperature. Elemental analysis indicated that TP-doped nanohybrid scaffolds experienced higher amount of PDA immobilization as compared to pristine and nHA-doped scaffolds. The unoccupied 'd' orbital of introduced Ti can form a coordinate bond with catechol groups of dopamine (DA) which augments PDA deposition on the scaffold's surface. Furthermore, the higher effective nuclear charge (Z⁎) of tetravalent Ti ion generates an effective dative bond with the urethane groups of PU chain which improves hardness and tensile strength (TS) of produced nanocomposites (PU/TP-nHA) remarkably by 71.3 % and 126 % compared to pristine PU. Ti-doped nanohybrid scaffolds, containing calcium and phosphate components with higher amounts of deposited PDA exhibited improved in vitro osteogenic bioactivity. Moreover, in vivo study expressed superior bone regeneration efficacy of the TP-doped nHA-integrated PU scaffold without showing any organ toxicity. Thus, the optimum level of TP-doped nHA with higher amount of PDA-immobilized PU nanohybrid scaffold would be a suitable bone graft substitute in bone regeneration applications.

Stainless-steel screws are commonly used for fragment fixation during periacetabular osteotomy (PAO) at our institutions. Titanium is reserved for patients with documented nickel allergies. Titanium screws possess a significantly lower Young's modulus than stainless steel and, therefore, potentially less resistance to physiologic loading. Thus, we hypothesized that the use of titanium screws might be associated with changes in acetabular correction prior to healing. The aim of this study was to compare the maintenance of acetabular correction following PAO using stainless-steel or titanium screws. A documented nickel allergy was confirmed with an allergy specialist. Patients' age at surgery, gender and BMI were collected. The lateral center-edge angle of Wiberg (LCEA), medial center-edge angle (MCEA), anterior wall index (AWI), posterior wall index (PWI) and Tonnis angle were measured. The delta value for radiographic parameters was calculated as the difference between values immediately post-operation and at 6 months post-operation. Only age at surgery (P < 0.001) and the pre-operative LCEA (P = 0.013) were significantly different between groups (Tables I and II). The remaining pre- and post-operative radiological measurements were similar (Table II). Comparison of delta values at 6 months follow-up indicated no significant differences between screw types (Table III). No patients in the titanium group had a trans-iliac retrograde screw included in their construct (P = 0.003). All patients healed from their osteotomies. The use of titanium screws in patients with an allergy to nickel was not associated with differences in acetabular correction or the rate of osseous union rates despite its lower inherent mechanical properties.

Critical sized bone defects are difficult to manage and currently available clinical/surgical strategies for treatment are not completely successful. Polycaprolactone (PCL) which is a biodegradable and biocompatible thermoplastic can be 3D printed using medical images into patient specific bone implants. The excellent mechanical properties and low immunogenicity of PCL makes it an ideal biomaterial candidate for 3D printing of bone implants. Though PCL suffers from the limitation of being bio-inert. Here we describe the use of PCL as a biomaterial for 3D printing for bone regeneration, and advances made in the field. The specific focus is on the different 3D printing techniques used for this purpose and various modification that can enhance bone regeneration following the development pathways. We further describe the effect of various scaffold characteristics on bone regeneration both in vitro and the translational assessment of these 3D printed PCL scaffolds in animal studies. The generated knowledge will help understand cell-material interactions of 3D printed PCL scaffolds, to further improve scaffold chemistry and design that can replicate bone developmental processes and can be translated clinically.

This pediatric orthopaedic update represents a review of articles predominantly from October 2020 to October 2021. Trauma Supracondylar Humeral Fractures The conventional wisdom on remodeling was challenged by Gamble and Vorhies, who showed remodeling of up to 100% capitellar displacement in children <5 years of age with sagittal plane malunions. However, of note, patients >8 years of age had little to no remodeling capacity1. Bekmez et al. studied older patients (7 to 15 years of age) with supracondylar humeral fractures (Sauvegrain ≥ 1) treated with percutaneous pinning. Although the lack of pin spread (p < 0.01) or of bicolumnar fixation (p < 0.01) was associated with a loss of reduction, age and skeletal maturity were not, showing that this is a viable treatment option even in an older age group2. Radial Fractures In a series of radial neck fracture closed reductions, 0 of 10 patients with fracture angulation of ≥60° and only 1 of 14 patients presenting >24 hours after the injury had a successful reduction in the emergency room3. Lynch et al. studied remodeling of distal radial fractures in the coronal plane and discovered that this occurred at a rate of 2° per month. They recommended against manipulation for coronal angulation of <24°4. Lower-Extremity Fractures Jian et al. described a salvage technique for the management of old femoral neck fractures (>3 weeks) with a corticoperiosteal pedicle flap from the greater trochanter. In their series of 23 patients, there were no nonunions and the rate of osteonecrosis was 13%5. Siddiqui et al. reviewed a series of 58 femoral shaft fractures treated with titanium elastic nails, of which 26 (45%) were length-unstable. There was no difference between the stable and unstable fracture patterns with regard to the incidence of major complications (p = 0.68) or minor complications (p > 0.99)6. In their study, Lurie et al. compared the use of trans-syndesmotic screw fixation with that of suture buttons for the management of syndesmotic injuries. Although both techniques maintained the reduction, 36 (80%) of 45 patients in the screw group underwent a surgical procedure for implant removal compared with 4 (12.5%) of 32 patients in the suture button group (p < 0.00001)7. In a series of 83 patients, an alternative technique of lag screws alone for the management of unstable lateral malleolar fractures was compared with traditional plate fixation. Both groups had 100% union rates without a loss of reduction; however, the mean surgical time was longer in the plate group at 64 minutes compared with the lag screw group at 49 minutes (p = 0.001), and the plate group was 3.8 times more likely to have symptomatic implants (p < 0.044) than the lag screw group8. A randomized controlled trial comparing an above-the-knee cast with a controlled ankle motion (CAM) orthosis (CAM boot) for the treatment of nondisplaced tibial fractures (toddlers’ fractures) showed no difference in fracture healing, but early ambulation was more common in the CAM boot group, with 78% of patients weight-bearing at 7 to 10 days compared with 54% of those in the cast group9. Spine Adolescent Idiopathic Scoliosis Shin et al. performed a systematic review of outcomes of tethering and posterior spinal fusion for adolescent idiopathic scoliosis in 10 anterior vertebral body tethering studies (211 patients) and 14 posterior spinal fusion studies (1,069 patients). The pooled reoperation rate for studies with a minimum follow-up of 36 months was 24.7% with anterior vertebral body tethering compared with 1.8% with posterior spinal fusion. The deformity correction, clinical outcomes, and intermediate-term Scoliosis Research Society (SRS)-22 scores were similar between the 2 groups, and the authors noted that, despite the potential for and excitement over anterior vertebral body tethering, caution should be exercised10. Concerns have been raised with regard to a unilateral posterior peri-apical distraction device (ApiFix). In a series of 20 patients with adolescent idiopathic scoliosis and a mean follow-up of 3.4 years, 10 patients had serious complications requiring revision. The study was terminated early due to safety concerns11. Given advancements in quality and safety, Mehta et al. reviewed the rate of unplanned returns to the operating room for patients with adolescent idiopathic scoliosis undergoing spinal fusion and found that this rate decreased 0.46% per year from 1997 to 201312. In a review of patients undergoing posterior spinal fusion, Hughes et al. noted continued improvement from 2 to 5 years postoperatively with regard to the rate of coronal imbalance of >2 cm, which decreased from 17% to 6%, and shoulder asymmetry of >2 cm, which decreased from 8% to 1%13. Farrell et al. elegantly demonstrated that the pulmonary dysfunction in patients with adolescent idiopathic scoliosis is not only restrictive but also obstructive. Correlating low-dose computed tomographic (CT) scans with pulmonary function tests, the authors found that chest intrusion creates right-sided bronchial narrowing and lung function loss in preoperative patients with adolescent idiopathic scoliosis, with nearly half (48%) of patients having a percent-of-predicted forced expiratory volume in 1 second (FEV1%) or percent-of-predicted forced vital capacity (FVC%) that was <65% compared with controls14. Early-Onset Scoliosis A case-matched comparison of patients with severe early-onset scoliosis (≥90°) treated with magnetically controlled growing rods compared with traditional growing rods showed that the 2-year unplanned revision-free survival was 91% in the magnetically controlled growing rod group compared with 71% in the traditional growing rod group15. Mathew et al. found that serum titanium, cobalt, and chromium levels were elevated in children with spinal implants, particularly with growing spine devices, although the clinical importance of this remains uncertain16. Mackey et al. compared older patients (ages 8 to 11 years) with early-onset scoliosis treated with magnetically controlled growing rods, posterior spinal fusion, or vertebral body tethers. They found quality-of-life improvements with spinal fusion and vertebral body tethers but not with magnetically controlled growing rods. With a mean follow-up of 3 years, the complication rate was lower for patients who underwent fusion at 14% compared with 27% in the vertebral body tether group and 61% in the magnetically controlled growing rod group (p < 0.0005), adding to the growing body of evidence that this intermediate age group may be best served by a 1-stage fusion17. Neuromuscular Scoliosis In a series of 198 patients with neuromuscular scoliosis, Stephan et al. demonstrated that the rate of postoperative infection following spinal fusion decreased from 16.1% to 4.4% with the institution of recommendations from the 2013 Best Practice Guideline, showing the significant impact (p = 0.005) of preventive measures in this high-risk population18. Using the Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) questionnaire, Miller et al. prospectively evaluated 157 patients with nonambulatory cerebral palsy undergoing posterior spinal fusion. Meaningful improvement was observed at 2 years in 36% of patients; however, with the absence of a control group, it is possible that even maintaining similar quality-of-life scores represents improvement over the natural history19. Infection In a series of nearly 600 patients hospitalized with septic arthritis or osteomyelitis, Lansell et al. found no difference in the culture positivity rate in patients pretreated with antibiotics, with regard to bone cultures (75% for the pretreated group compared with 64% for the group not pretreated; p = 0.29), joint cultures (39% for the pretreated group compared with 39% for the group not pretreated; p = 0.95), or blood cultures (44% for the pretreated group compared with 42% for the group not pretreated; p = 0.62). These results suggest that empiric antibiotics can be initiated early without impacting the ability to identify the responsible organism20. Ramchandar et al. compared patients with culture-proven methicillin-sensitive Staphylococcus aureus osteoarticular infections (septic arthritis or osteomyelitis) who transitioned from intravenous antibiotics to either 4 times daily or 3 times daily oral dosing of cephalexin and found equivalent efficacy with the more convenient 3 times daily dosing21. Hamilton et al. found that patients with septic arthritis and contiguous osteomyelitis had longer hospitalizations (median, 8.0 compared with 4.0 days), a higher readmission rate (17.1% compared with 5.2%), a higher complication rate (38.1% compared with 0.7%), and a higher rate of intensive care (21.0% compared with 1.5%) when compared with patients with septic arthritis alone22. Cerebral Palsy Hip In a recent study, Terjesen and Horn showed that the femoral head-shaft angle in young children was not a predictor of late hip displacement, and, therefore, measurement of this angle was considered unnecessary during hip surveillance in patients <5 years of age23. In 229 children with spastic quadriplegic cerebral palsy and severe scoliosis, Hadad et al. evaluated factors associated with hip stability. They found that gestational age of ≥37 weeks, female sex, and normal brain magnetic resonance imaging (MRI) findings were associated with a lower risk of hip displacement24. Carroll et al. evaluated factors influencing outcomes in the dysplastic hip in children with nonambulatory cerebral palsy and found that pelvic osteotomy had a positive effect on hip reconstruction outcomes with severely subluxated hips. However, capsulorrhaphy did not improve the rate of success in this population25. Knee In patients undergoing distal femoral extension osteotomies for knee flexion contractures, patellar tendon imbrication for extensor mechanism shortening was associated with significant improvements in quadriceps strength, knee extensor lag, and popliteal angle (p < 0.01)26. Rectus femoris tendon transfer and resection were compared, and both resulted in an improvement in peak knee flexion during swing. However, the transfer technique resulted in a greater tendency to crouch in children with Gross Motor Functional Classification System (GMFCS) Levels III and IV, which was not observed in the resection group27. Foot and Ankle Stotts et al. found that revision of gastrocnemius-soleus complex lengthening was needed in around 40% of patients who were <7 years of age and had GMFCS Level III28. Lower revision rates were found for older patients and patients who had GMFCS Levels I and II28. Rethlefsen et al. found that both calcaneal lengthening osteotomy and calcaneal slide osteotomy were effective in providing planovalgus foot correction. Talonavicular fusion, when combined with calcaneal slide osteotomy, provided superior results and was considered a key to success in patients with low functional levels29. Pediatric Foot Deformity In the management of clubfoot, Monforte et al. found comparable results using plaster of Paris or semirigid fiberglass while performing Ponseti casting30. Ankle dorsiflexion after Ponseti treatment was shown to be influenced by age and the initial severity of clubfoot. Overall, ankle dorsiflexion of around 20° was maintained through the age of 3 years, and dorsiflexion of 15° was maintained through the age of 5 years. Values lower than these thresholds were suggested as possible indicators of relapse31. Using 7 pairs of cadaveric feet, Siebert et al. analyzed the occurrence of calcaneocuboid subluxation with lateral column lengthening with and without the use of a Steinmann pin. The authors found that subluxation occurred in both groups and proposed the use of 2 pins to potentially prevent this rotatory subluxation32. Another anatomic study showed the presence of an accessory cuboid facet in 75% of feet that have calcaneonavicular coalition33. In the treatment of congenital vertical talus, a minimally invasive approach, consisting of serial casting followed by talonavicular joint reduction and Achilles tenotomy, demonstrated overall good outcomes34. However, although no recurrence was seen in idiopathic deformities, 29% of syndromic clubfeet had recurrence34. Lower-Extremity Alignment Several studies focused on predicting remaining growth35-37. Combining multiple methods was recommended for higher accuracy in growth prediction36,37. Proximal tibial metaphyseal width and lateral tibial epiphyseal height seem ideal to determine the growth remaining in children38. In addition, epiphyseal-metaphyseal ratio measurements around the knee, when combined with sex and chronological age, were comparable with the Greulich and Pyle technique for the estimation of skeletal maturity39. The Roche-Wainer-Thissen system using 7 radiographic parameters around the knee was also supported and was found to be resilient to rotational variations40. The White-Menelaus formula with skeletal age was recommended to predict lower-extremity segment length at maturity35. Hemiepiphysiodesis continues to be a topic of interest. Screw configuration in tension-band plating systems did not show an effect on the rate of correction41. A prospective study of 48 patients undergoing tension-band plating showed that, at 1 month postoperatively, 65% of the patients had not yet returned to their preoperative activity level, which can be used in guiding preoperative discussions42. The use of a percutaneous retrograde transphyseal screw was also effective for hemiepiphysiodesis43. A recent femoral lengthening technique of using extramedullary (submuscular) placement of magnetically lengthening nails in a retrograde fashion with a 10° bend matching the distal femoral metaphysis revealed promising early results. Satisfactory and safe deformity correction and lengthening can be achieved with careful patient selection and reasonable lengthening goals44. Although good outcomes were seen with vascularized fibular grafting in the management of congenital tibial pseudarthrosis, ankle valgus at the donor site occurred despite tibiofibular synostosis45. Upper Extremity Kazarian et al. compared the cost-effectiveness of surgical release with that of botulinum toxin injections in treating upper-extremity cerebral palsy. The authors concluded that a surgical procedure provided a greater benefit at a lower cost and suggested that botulinum toxin injections should be used sparingly in this population; the potential cost savings could be $5.6 billion to $11.3 billion annually in the United States46. A systematic review and meta-analysis of 13 articles showed that arthroscopic release improved shoulder mobility and bone deformity in young children with brachial plexus birth injury47. In a study of 78 patients, at a follow-up of 5 years, 32% of pediatric trigger thumbs resolved spontaneously and 43% eventually had a surgical release. At 3 years, patients who had had interphalangeal joint flexion contractures of >30° at baseline often lacked spontaneous resolution; it may be reasonable to consider these patients as early surgical candidates48. In a series of 125 patients with acute posterior sternoclavicular dislocations, 11 patients underwent successful closed reduction, and 114 patients (91%) underwent open reduction and internal fixation. Compression without laceration of the ipsilateral brachiocephalic vein was common on axial imaging (50%), but there were no vascular or mediastinal injuries that required intervention. Regardless, the authors acknowledged that an injury to the vascular structures is potentially catastrophic and urged careful consideration of institutional interventional resources for patient safety49. Zheng et al. concluded that improvements in elbow motion, especially supination, could be achieved following surgical reconstruction of missed Monteggia lesions at a mean time of 12.9 weeks after the injury. Seventy-five percent of patients achieved radiocapitellar stability, and 6 of 52 patients had a further surgical procedure for instability. Repair of the anular ligament, rather than its reconstruction or lack of its treatment, increased radiocapitellar stability50. Sports Anterior Cruciate Ligament (ACL) Mitchell et al. theorized that an ACL-deficient knee would have a more vertical orientation of the lateral collateral ligament (LCL) and that the LCL could then be seen on a single coronal slice, termed the coronal LCL sign. In a series of 153 adolescents with ACL reconstruction, the authors found that the coronal LCL sign was predictive of an anterolateral complex injury, with an odds ratio of 4.3 for ACL graft failure51. A multicenter cohort of patients with tibial eminence fractures was reviewed for subsequent ACL rupture. Of the 385 patients, ACL injuries occurred at a rate of 2.6% with a median follow-up of 6.5 months. The median time to rupture was 10.2 months following operative fracture treatment, and rupture most commonly occurred with completely displaced (type-III or IV) fractures. Of note, in patients with follow-up of at least 2 years, the rate of ACL rupture increased to 21.7%52. In a series with a mean follow-up of 10 years, Martin et al. evaluated the lateral posterior tibial slope in skeletally immature patients with ACL injuries initially managed nonoperatively. The authors found that the posterior slope increased in the ACL-injured knee more than in the contralateral side over the study period. Twenty-two patients had ACL reconstruction during the study period and 16 did not, and the posterior tibial slope was not predictive of surgical intervention53. Discoid Meniscus Logan et al. reported on 470 cases of symptomatic discoid menisci in adolescents and found a high rate of failure with nonoperative treatment (39%), common findings of a meniscal tear (63%) and instability, and a high rate of either reoperation or continued symptoms postoperatively (33%)54. Another group, which included 2 authors of the previous group, also conducted a survey following lateral meniscal rim-preserving surgery in 25 patients with a mean age of 10.8 years at the time of the surgical procedure. At a minimum follow-up of 15 years, two-thirds of patients were satisfied with their outcomes, although nearly half of patients underwent revision saucerization55. Patellar Instability Lin et al. investigated the association between external tibiofemoral rotation and the increased risk of a medial patellofemoral ligament injury and concluded that the degree of tibiofemoral rotation is correlated with the severity of patellar instability. The authors postulated that high external tibiofemoral rotation may be an important factor in obligatory or fixed dislocators and, with further understanding, may become a surgical target or a prognostic factor56. Similarly, Ling et al. sought to develop a model to predict recurrent instability in first-time patellar dislocators. The authors determined that age, Insall-Salvati ratio, history of contralateral patellar dislocation, tibial tubercle-trochlear groove (TT-TG) distance, skeletal immaturity, lateral patellar tilt, and trochlear dysplasia were the most important predictors of recurrent dislocation, but cautioned that prospective validation is needed57. Shoulder Yapp et al. sought to determine the incidence of recurrent instability following shoulder dislocation in patients who were ≤14 years of age. The authors found that recurrent dislocation occurred in 18 (43.9%) of 41 patients at a median of 14.7 months after the injury. Skeletal maturity was associated with recurrent instability (6 of 24 immature patients compared with 12 of 17 mature patients; p = 0.01). Twenty percent of patients with recurrent instability and a mean of 8 dislocations required surgical intervention58. Hip Hip Preservation Hassan et al. queried the Pediatric Health Information System (PHIS) Database for patients who underwent hip arthroscopy and were between 10 and 19 years of age and found that, over 10 years, the number of hip arthroscopies had a 3.9-fold increase compared with the number of total orthopaedic surgical procedures in adolescents. The authors postulated that this increase may be due to improved understanding of hip pathology and increasing sports participation59. Hanke et al. found that 52% of hockey players enrolled in a longitudinal MRI study at the ages of 12 and 13 years developed cam morphology within 3 years. The authors concluded that the cam lesion develops at the end of the growth spurt of the femoral head between the ages of 13 and 16 years60. Youngman et al. found that an increased α angle correlated with labral pathology, including severity of disease and increased tear length in patients undergoing a surgical procedure for femoroacetabular impingement61. Allahabadi et al. evaluated venous thromboembolism in adolescents who had undergone pelvic osteotomies and determined that the overall rate of venous thromboembolism was 0.61%. Aspirin was the most common anticoagulant, used in 47.6% of patients, but there was no difference in the overall venous thromboembolism rates between those who received prophylaxis and those who did not, highlighting the need for guidelines with regard to this aspect of postoperative care62. Southam et al. reported on pediatric and adolescent acetabular fractures treated with open reduction and internal fixation. Eighteen (86%) of 21 patients had a favorable functional outcome, although 2 patients with a delayed reduction (>6 hours) of a fracture-dislocation developed osteonecrosis63. Griffith et al. reviewed patients with sickle cell disease who had a mean age of 14 years and were undergoing core decompression with a bone marrow aspirate concentrate injection for femoral head osteonecrosis. At a mean follow-up of nearly 4 years, skeletally immature patients demonstrated regression of at least 1 Steinberg grade in 89% of cases and reconstitution of the femoral head in 78% of cases64. Rainer et al. reported on the outcomes of primary total hip arthroplasty in patients with open triradiate cartilage and a mean follow-up of 5.5 years. The mean postoperative Harris hip score was 92.3. Follow-up radiographs demonstrated osseointegration in 12 (92%) of 13 acetabular components, and the authors concluded that it is not necessary to await triradiate closure prior to total hip arthroplasty65. Slipped Capital Femoral Epiphysis (SCFE) St George et al. reported using a posterior sloping angle threshold of 14.5° for prophylactic fixation in preventing contralateral SCFE, which prevented 77% of subsequent SCFEs while decreasing unnecessary intervention. The authors also stated that a posterior sloping angle can increase over time and recommended that the protocol be used for the entire follow-up66. Comparing patients undergoing surgical hip dislocation for the sequelae of SCFE with patients who underwent arthroscopic surgery for primary femoroacetabular impingement, more diffuse cartilage injury was found in patients with SCFE. Lieberman et al. advocated for early surgical intervention in patients with symptomatic SCFE because of the risk of premature joint damage67. Sinha et al. reviewed 55 unstable SCFE cases and 255 stable SCFE cases to identify preoperative factors associated with osteonecrosis and found that there was greater superior translation in hips that developed osteonecrosis (17.2 mm) compared with hips that did not (12.9 mm) (p < 0.02)68. Legg-Calvé-Perthes Disease Selberg et al. hypothesized that variable anatomy supports the concept of anatomically specific containment in Legg-Calvé-Perthes disease. Of 168 patients, 35% were substantially dysplastic, 30% were in varus, and 12% were in valgus, suggesting that the one-surgery-fits-all approach may lack specificity for an individual patient69. Kim et al. performed a review of 65 patients, with a mean age of 7.9 years at the diagnosis of Legg-Calvé-Perthes disease, who underwent an early proximal femoral osteotomy and had a mean follow-up of 11.8 years. Of the patients who underwent early proximal femoral osteotomy, 40.5% bypassed the fragmentation stage. The degree of lateral pillar collapse was lower, and there were more patients with a spherical femoral head, in this bypass group70. Developmental Dysplasia of the Hip Lin et al. investigated the effect that an inverted acetabular labrum had on the outcomes of Pavlik harness treatment for developmental dysplasia of the hip in 229 hips. The authors found a significant difference (p < 0.001) in the incidence of Pavlik harness treatment failure: 91% (20 of 22) in the inverted labrum group and 27% (55 of 207) in the control group71. Imerci et al. assessed risk factors for Pavlik harness treatment failure and found that the onset of treatment after the seventh week of age, infants of multigravida mothers, and initial hip mobility (fixed-dislocated hips) by dynamic sonography were predictive of Pavlik harness treatment failure. Six percent of hips with no risk factors had failed Pavlik harness treatment, and treatment failure occurred in 42% of hips with 1 risk factor, 69% of hips with 2 risk factors, and 100% of hips with all 3 risk factors72. Theunissen et al. studied whether treatment duration was reduced by shortening the time to the first routine follow-up ultrasound after the initiation of a Pavlik harness. The median time of harness treatment was reduced from 12 weeks to 6.1 weeks (p < 0.001). Residual dysplasia at 1 year of age was detected in 17% of patients in the 12-week group compared with 11% of patients in the 6-week group (p = 0.189). The authors concluded that the first routine follow-up ultrasound can be safely accelerated from 12 to 6 weeks after harness initiation73. The impact of Pavlik harness weaning was evaluated and, although they had longer total harness time, infants treated with Pavlik weaning, compared with those who were not weaned, did not demonstrate different radiographic results at 1 year of age74. In their study, Morris et al. examined patients with late reduction of developmental dysplasia of the hip and found that patients treated with closed reduction had a higher rate of a secondary surgical procedure (47%) than those with open reduction (30%), despite a decreased severity of displacement. There was no difference in the prevalence of osteonecrosis: 22% for the closed reduction group and 19% for the open reduction group (p = 0.60)75. A review of 9,299 patients who presented from 1998 to 2019 was conducted to evaluate the impact of a universal newborn ultrasound screening program instituted in 2006. The mean age at presentation for developmental dysplasia of the hip decreased from 2.65 to 2.19 years with universal screening (p = 0.0067)76. In a prospective study, Murphy et al. described the implementation of a virtual clinic for developmental dysplasia of the hip and found that median waiting times from referral to treatment decision were reduced by >70% and that only 1.8% of parents opted for in-person appointments, demonstrating considerable cost savings without adverse outcomes77. Evidence-Based Orthopaedics The editorial staff of JBJS reviewed a large number of recently published studies related to the musculoskeletal system that received a higher Level of Evidence grade. In addition to articles cited already in this update, 5 other articles relevant to pediatric orthopaedic surgery are appended to this review after the standard bibliography, with a brief commentary about each article to help guide your further reading, in an evidence-based fashion, in this subspecialty area. Evidence-Based Orthopaedics Colaco K, Willan A, Stimec J, Barra L, Davis A, Howard A, Boutis K. Home management versus primary care physician follow-up of patients with distal radius buckle fractures: a randomized controlled trial. Ann Emerg Med. 2021 Feb;77(2):163-73. In this noninferiority randomized controlled trial, 149 patients underwent either home removal of a splint and follow-up as needed (referred to as home management) or evaluation in 1 to 2 weeks with a primary care physician. The outcomes in both groups were similar with regard to functional recovery and significant cost savings were demonstrated in the home management group, showing the viability of this treatment option. This study provides valuable information supporting a treatment option that is more convenient and cost-effective for both patients and providers in managing these mild injuries. James EW, Dawkins BJ, Schachne JM, Ganley TJ, Kocher MS, Anderson CN, Busch MT, Chambers HG, Christino MA, Cordasco FA, Edmonds EW, Green DW, Heyworth BE, Lawrence JTR, Micheli LJ, Milewski MD, Matava MJ, Nepple JJ, Parikh SN, Pennock AT, Perkins CA, Saluan PM, Shea KG, Wall EJ, Willimon SC, Fabricant PD; PLUTO Study Group. Early operative versus delayed operative versus nonoperative treatment of pediatric and adolescent anterior cruciate ligament injuries: a systematic review and meta-analysis. Am J Sports Med. 2021 Mar 15:363546521990817. In this systematic review and meta-analysis of 30 studies with 1,176 patients, both early and delayed operative treatment achieved knee stability. However, delaying ACL reconstruction for >12 weeks was associated with an increased risk of meniscal injuries (odds ratio, 0.23; p = 0.006) and irreparable meniscal tears (odds ratio, 0.31; p = 0.001). The results of nonoperative management were a low rate of return to sports, an increased risk of meniscal tears, and high rates of residual knee instability. This study demonstrated the importance of prompt management in pediatric ACL injuries to minimize the potential for associated meniscal injury and negative outcomes in this young patient population. Kelley-Quon LI, Kirkpatrick MG, Ricca RL, Baird R, Harbaugh CM, Brady A, Garrett P, Wills H, Argo J, Diefenbach KA, Henry MCW, Sola JE, Mahdi EM, Goldin AB, St Peter SD, Downard CD, Azarow KS, Shields T, Kim E. Guidelines for opioid prescribing in children and adolescents after surgery: an expert panel opinion. JAMA Surg. 2021 Jan 1;156(1):76-90. A multidisciplinary team reviewed current literature and the expert panel created a series of recommendations. The 3 themes highlighted were: (1) health-care professionals caring for children who require a surgical procedure must recognize the risk of opioid misuse; (2) nonopioid analgesic use should be optimized in the perioperative period; and (3) patient and family education with regard to safe opioid use should occur both before and after the surgical procedure. This effort represents the first opioid-prescribing guidelines for children following a surgical procedure and is a promising first step in a more cohesive approach to address the opioid epidemic. Lin Y, Lou E, Lam TP, Cheng JCY, Sin SW, Kwok WK, Wong MS. The intelligent automated pressure-adjustable orthosis for patients with adolescent idiopathic scoliosis: a bi-center randomized controlled trial. Spine (Phila Pa 1976). 2020 Oct 15;45(20):1395-402. This study investigated the use of an automated pressure-adjustable orthosis compared with a traditional orthosis for the management of adolescent idiopathic scoliosis and demonstrated enhanced wear, with a mean duration that was 1 hour longer, and a 34% higher targeted pressure in the pressure-adjustable orthosis group. Although this concept is intriguing, currently, this bracing option is not commercially available in the United States. It also appears quite prominent in the provided images, raising concerns about the generalizability of these results. Singh KA, Shah H, Joseph B. Comparison of plaster-of-Paris casts and Woodcast splints for immobilization of the limb during serial manipulation and casting for idiopathic clubfoot in infants. Bone Joint J. 2020 Oct;102-B(10):1399-404. In this randomized controlled trial, 23 idiopathic clubfeet were immobilized with plaster-of-Paris casts and 23 clubfeet were treated with Woodcast splints that only encircled two-thirds of the limb. The time required for the application and removal of Woodcast splints was significantly less than that for the plaster-of-Paris casts (p < 0.001), although both treatments had similar effectiveness in maintaining the deformity correction. In this small series, Woodcast splints showed promise as an alternative to the traditional Ponseti method. Although further study is warranted, this has exciting potential to increase clinic efficiency given its decreased application and removal time while achieving similar outcomes.

Objectives: To evaluate the functional outcomes of pediatric and adolescent patients (<18 year old) who sustained acetabulum fractures that were treated with open reduction internal fixation (ORIF). Design: Retrospective cohort. Setting: Level 1 trauma center. Patients: Thirty-four pediatric and adolescent patients underwent acetabulum fracture ORIF between 2001 and 2018. Of the operatively treated patients, 21 patients had sufficient follow-up (>6 months), one died after fixation secondary to other traumatic injuries, and 12 patients were lost to follow-up. Intervention: Acetabulum fracture ORIF. Main Outcome Measurement: The SF-36 Health Survey and Short Musculoskeletal Functional Assessment (SMFA) were compared with population norms. The modified Merle d'Aubigné clinical hip score, Matta radiologic outcome, and postoperative complications were also documented. Results: Functional outcome data were available at a mean of 5 years 2 months. Mean SF-36 scores were 44.8 and 50.1 for the physical component score and mental component scores, respectively, which did not differ significantly from US population norms (physical component score mean: 50, P = 0.061 and mental component score mean: 50, P = 0.973). Furthermore, the mean SMFA Bother Index score was 18.6, which is not significantly different from the population norm mean of 13.8 (P = 0.268). However, the function index mean was 31.9, which was significantly worse than the population norm mean of 12.7 (P = 0.001). Two patients with a delayed reduction (>6 hours) of an acetabulum fracture dislocation had poor outcomes related to the development of avascular necrosis and post-traumatic osteoarthritis. Conclusion: In this small cohort, 86% (18/21) of these patients had a favorable functional outcome with the exception of the SMFA Functional Index that was significantly less than population norms. Although long-term follow-up is needed, we advocate for operative management of pediatric and adolescent acetabulum fractures when adult displacement and instability criteria are present. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background Acetabular retroversion is observed frequently in healed Legg–Calvé–Perthes disease (LCPD). Currently, it is unknown at which stage and with what prevalence retroversion occurs because in non-ossified hips, retroversion cannot be measured with standard radiographic parameters. Methods In a retrospective, observational study; we examined pelvic radiographs in children with LCPD the time point of occurrence of acetabular retroversion and calculated predictive factors for retroversion. Between 2004 and 2017, we included 55 children with a mean age of 5.7 ± 2.4 years at diagnosis. The mean radiographic follow-up was 7.0 ± 4.4 years. We used two new radiographic parameters which allow assessment of acetabular version in non-ossified hips: the pelvic width index and the ilioischial angle. They are based on the fact that the pelvic morphology differs depending on the acetabular version. These parameters were compared among the four Waldenström stages and to the contralateral side. Logistic regression analysis was performed to determine predictive factors for acetabular retroversion. Results Both parameters differed significantly among the stages of Waldenström ( p < 0.003 und 0.038, respectively). A more retroverted acetabulum was found in stage II and III (prevalence ranging from 54 to 56%) compared to stage I and IV (prevalence ranging from 23 to 39%). In hips of the contralateral side without LCPD, the prevalence of acetabular retroversion was 0% in all stages for both parameters. Predictive factors for retroversion were younger age at stage II and IV, collapse of the lateral pillar in stage II or a non-dysplastic hip. Conclusions This is the first study evaluating acetabular version in children with LCPD from early stage to healing. In the developing hip, LCPD may result in acetabular retroversion and is most prevalent in the fragmentation (stage II) and early healing stage (stage III). Partial correction of acetabular retroversion can occur after healing. This has a potential clinical impact on the timing and type of surgical correction, especially in pelvic osteotomies for correction of acetabular version. Level of evidence Level III, retrospective observational study.

Treatment options for large osteochondral injuries (OCIs) are limited by donor tissue scarcity, morbidity, and anatomic mismatch. 3D printing technology can produce patient-specific scaffolds to address these large defects. Thermoplastics like polycaprolactone (PCL) offer necessary mechanical properties, but lack bioactivity. We fabricated 3D printed PCL scaffolds embedded with polylactic acid microspheres containing decellularized cartilage matrix (DM). DM incorporation within polylactic acid microspheres prevented its thermal degradation during the 3D printing process. The scaffolds replicated the mechanical properties of native cartilage and demonstrated controlled release of DM proteins. Human mesenchymal stem cells (hMSCs) seeded on the composite scaffolds with DM and cultured in basal media self-assembled into aggregates mimicking mesenchymal condensates during embryonic development. The DM composite scaffolds also induced higher expression of biochemical markers of cartilage development than controls, providing evidence for their translational application in the treatment of OCIs. The present study demonstrates the potential of direct incorporation of DM with thermoplastics for 3D printing of patient-specific scaffolds for osteochondral regeneration.

3D printed hydrogels have emerged as a novel tissue engineering and regeneration platform due to their ability to provide a suitable environment for cell growth. To obtain a well-defined scaffold with good post-printing shape fidelity, a proper hydrogel ink formulation plays a crucial role. In this regard, alginate has received booming interest owing to its biocompatibility, biodegradability, easy functionalization, and fast gelling behavior. Hence, this review highlights the significance of alginate-based hydrogel inks for fabricating 3D printed scaffolds for bone and cartilage regeneration. Herein, we discuss the fundamentals of direct extrusion 3D bioprinting method and provide a comprehensive overview of various alginate-based hydrogel ink formulations that have been used so far. We also summarize the requirements of hydrogel inks and 3D printed scaffolds to achieve similarity to the native tissue environment. Finally, we discuss the challenges, and research directions relevant for future clinical translation.

AbstractTotal hip arthroplasty (THA) in pediatric patients is controversial with concern for high failure rates, and lack of promising outcomes as compared with the adult population. Increased survivorship of implants invites the potential for improved function and quality of life in young adults. Although THA is now an option for end-stage symptomatic hip disease in young patients, outcomes with contemporary techniques and implants have yet to be reported.Following the institutional review board approval, a retrospective chart review of 25 patients (29 hips) with end-stage hip disease at a single institution from 2010 to 2017 was performed. All patients underwent THA with noncemented, contemporary THA with highly cross-linked polyethene liners. Clinical, radiographic, and patient-reported outcomes were obtained including any postoperative complications, revisions, evidence of loosening or wear, and lastly, Western Ontario & McMaster Universities Osteoarthritis Index, Harris Hip Scores, Non-Arthritic Hip scores, and International Hip Outcome Tool. With a minimum follow-up duration of 2 years, there were no revisions or evidence of loosening or wear on follow-up radiographs. All patients underwent noncemented THA with metal or ceramic on highly cross-linked polyethylene liners. Six patients accounting for seven THAs completed patient-reported outcomes: two reporting excellent outcomes, four good outcomes, and one failed outcome. With advancing techniques and strategies, treatment options for hip pathology in the pediatric population are growing. We present favorable outcomes 2 years post-procedure, suggesting THA as a potential option for end-stage hip disease in pediatric and young adult patients.

Abstract Perioperative pain management protocols have a significant impact on early surgical outcomes and recovery. We hypothesized that multimodal protocol including fascia iliaca compartment nerve block (MM-FICNB) would decrease the length of hospital stay (LOS) by facilitating earlier mobilization, without compromising analgesia, compared to a traditional lumbar epidural-based protocol (EP). Demographics/comorbidities, surgical/block characteristics and perioperative pain/mobilization data were collected from a prospectively recruited MM-FICNB group (N = 16) and a retrospective EP cohort (N = 16) who underwent PAO using similar surgical techniques, physical therapy/discharge criteria. Association of MM-FICNB group with LOS (primary outcome), postoperative pain, postoperative opioid requirements in morphine equivalent rates (MER) (mcg/kg/h) and time to complete physical therapy were tested using multivariable and survival regression. Patient and surgical characteristics were similar between groups. Median time for FICNB performance was significantly less than epidural (6 versus 15 min; P < 0.001). LOS was significantly decreased in the MM-FICNB group (2.88 ± 0.72 days) compared to the EP group (4.38 ± 1.02 days); P < 0.001. MM-FICNB group had significantly lower MER on POD1 (P = 0.006) and POD2 (P < 0.001), with similar pain scores on all POD. MM-FICNB group was associated with decreased LOS and earlier mobilization (P < 0.001) by covariate-adjusted multivariate regression. Cox proportional hazard regression model showed MM-FICNB subjects had 63 (95% CI 7–571, P < 0.001) times the chance of completing physical therapy goals, compared to EP. Compared to EP, MM-FICNB protocol allowed earlier mobilization and decreased post-surgical hospitalization by 1.5 days, without compromising analgesia, with important implications for value-based healthcare and cost-effectiveness.

Along with other proteins in the coagulation cascade, including tissue factor and thrombin, fibrinogen has been shown to promote tumor metastasis across numerous cancer types. However, the role of fibrin(ogen) in primary tumor growth is context dependent and not universally important. One cancer strongly dependent on fibrin(ogen) for primary tumor growth is colorectal cancer (CRC), but the mechanisms by which fibrinogen supports colon cancer growth are not well understood. To delineate the mechanism of fibrin(ogen)-supported tumor growth, we implanted C57BL/6-derived murine colon cancer cells (MC38) into the dorsal subcutis of syngeneic mice with specific deletions/alteration in fibrinogen or FXIII-deficiency. Complete fibrinogen deficiency significantly limited the growth of colon cancer cells. However, the imposition of FXIII-deficiency or specific mutations in fibrinogen that 1) prevent the formation of fibrin polymer (FibAEK), limit fibrin(ogen) binding to the integrin αMβ2 (Fibɣ390-396A), or remove the ɣ chain binding motif for the platelet integrin αIIbβ3 (FibɣΔ5) had no impact on colon cancer growth. To explore the mechanisms coupling fibrin(ogen) to colon cancer growth using a nonbiased approach, we performed RNA-Seq analyses of murine CRC tumors harvested from Fib+ and Fib- mice. We detected significant differences in the expression of 214 genes (128 downregulated and 86 upregulated) involved in cellular proliferation, survival, migration and metabolism. Notably, Stratifin (SFN), which encodes 14-3-3-σ, was one of the genes found to be highly upregulated in tumors from Fib- mice relative to Fib+ mice. 14-3-3-σ is a potent cell cycle regulator and it is also known to stabilize p53, which ultimately inhibits tumor growth. In a separate validation cohort, we observed significantly increased protein expression of 14-3-3-σ and its upstream and downstream targets (i.e., p53, p21 and p27) in tumors harvested from Fib- mice relative to controls. We also compared FAK activation, a key negative regulator of p53, in tumors from Fib+ and Fib- mice. FAK was inactive in tumors from Fib- mice, as indicated by lack of phosphorylation at tyrosine 397 (p-FAK Tyr397). Also, MDM2 was less phosphorylated at Ser166 in Fib- tumors, suggesting that p53 is not degraded by MDM2 in the absence of fibrinogen. Taken together, these data suggest that fibrin(ogen)-mediated downregulation of p53 and other targets via FAK activation and downregulation of 14-3-3-σ results in senescence of CRC cells. Consistent with this view, Ki67 positive nuclei were significantly less in tumor from Fib- mice relative to controls We also observed senescence-associated-β-galactosidase (SA-β-gal) activity in the tumors from Fib- mice, but not those from Fib+ animals. Furthermore, NMR-based metabolomics analyses demonstrated significantly less NAD+ and lactate levels in tumors from Fib- mice, which further confirms that fibrinogen deficiency hampers proliferation by inhibiting major metabolic pathways. In order to determine if fibrinogen-mediated support of CRC growth is tumor cell intrinsic, we compared MC38 growth in the 3D bioprinted matrices consisting of fibrin or albumin. MC38 cells showed a higher proliferation rate in the fibrinogen printed 3D environment compared to the albumin environment. These findings suggest that fibrin(ogen)-mediated engements of tumor cells activates FAK which inhibits p53 and its downstream targets including 14-3-3-σ and p21 which promote cellular proliferation and prevent senescence. Overall, these studies suggest that fibrin(ogen) is the important component of the CRC microenvironment and could be exploited for targeting and treating the CRC. Disclosures Whitlock: POSNA: Other: Research Committee; MTF Biologics Grant Program: Other: site co-investigator. Palumbo:Ionis Pharmaceuticals: Research Funding.

Objectives: To investigate the association of obesity with fracture characteristics and outcomes of operatively treated pediatric supracondylar humerus fractures. Design: Retrospective multicenter. Setting: Two Level I pediatric hospitals. Patients: Patients (age <18 years) with operatively treated Gartland type III and type IV fractures 2010–2014. Intervention: Closed or open reduction and percutaneous pinning of supracondylar humerus fractures. Main Outcome Measure: Incidence of Gartland IV fracture, preoperative nerve palsy, open reduction and complication rates. Results: Patients in the obese group had a significantly higher likelihood of having a Gartland IV fracture (not obese: 17%; obese: 35%; P = 0.007). There was a significantly higher incidence of nerve palsy on presentation in the obese group (not obese: 20%; obese: 33%; P = 0.03). No significant differences were found between groups regarding incidence of open reduction, compartment syndrome, and rates of reoperation. Conclusions: The present study demonstrates that obese children with a completely displaced supracondylar humerus fractures have an increased risk of Gartland type IV and preoperative nerve palsy compared with normal weight children. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The corona mortis (CM) is a vascular connection between the obturator and external iliac or internal epigastric vessels that has historically been identified as a source of hemorrhage in pelvic surgery. However, its frequency, location, proximity to the osteotomies performed, vascular contributions and impact on blood loss in patients undergoing periacetabular osteotomy (PAO) are unknown. We sought to identify the frequency, origin, location relative to osteotomies performed during surgery and impact on blood loss of the CM. Preoperative magnetic resonance imaging (MRI) of the hips of 28 adolescent patients (56 hips) undergoing PAO was retrospectively reviewed for the presence of a CM. When identifiable, the size, nature (arterial or venous), orientation, position relative to the iliopectineal eminence (IPE) and associated estimated blood loss (EBL) were recorded. 75% (21/28) of patients possessed an identifiable, ipsilateral CM to the site of PAO, 90% of which were venous and 10% arterial. The vessel was typically 8.3 ± 3.8 mm medial and 11.1 ± 5.3 mm caudal from the anterosuperomedial edge of the IPE. There was no significant difference in the amount of EBL (519 ± 260 versus 694 ± 369 ml) or need for post-op transfusions (1/21 versus 0/7) between patients who possessed a CM and those who did not, respectively (P = 0.21). CM was more prevalent in this study than previously reported. However, the presence of an ipsilateral CM was not associated with an increase in EBL or transfusion during routine PAO surgery using modern surgical techniques.