Ten-year Review of Acute Pediatric Hematogenous Osteomyelitis at a New Zealand Tertiary Referral Center.

BACKGROUND: Acute hematogenous osteomyelitis (AHO) remains a cause of severe illness among children with the possibility of long-term consequences for growth and development. Recent research has highlighted an unusually high burden of disease in the New Zealand population compared with other Western regions. We have sought to identify trends in presentation, diagnosis, and management of AHO, with added focus on ethnicity and access to health care. METHODS: A 10-year retrospective review of all patients <16 years with presumed AHO presenting to a tertiary referral center between 2008 and 2018 was performed. RESULTS: One hundred fifty-one cases met inclusion criteria. The median age was 8 years with a male predominance (69.5%). Staphylococcus aureus was the most common pathogen using traditional laboratory culture method (84%). The number of cases per year decreased from 2008 to 2018. Assessment using New Zealand deprivation scores showed Maori children were most likely to experience socioeconomic hardship ( P ≤0.01). Median distance traveled by families to first hospital consult was 26 km (range 1 to 178 km). Delayed presentation was associated with need for prolonged antibiotic therapy. Incidence of disease varied by ethnicity with 1:9000 cases per year for New Zealand European, 1:6500 for Pacific, and 1:4000 for Maori. Overall recurrence rate was 11%. CONCLUSIONS: The incidence of AHO in New Zealand is concerningly high within Maori and Pacific populations. Future health interventions should consider environmental, socioeconomic, and microbiological trends in the burden of disease. LEVEL OF EVIDENCE: Retrospective study, Level III.

An Update on Pediatric Acute Hematogenous Osteomyelitis in New Zealand - A Decade on.

INTRODUCTION: New Zealand (NZ) has high rates of pediatric acute hematogenous osteomyelitis (AHO) with males and children of Pasifika and Maori ethnicity overrepresented. AIMS: To update the incidence of Pediatric AHO over 10 years, identifying trends in presentation, organisms, treatment, and outcomes. METHODS: A 10-year retrospective review of children aged 6 weeks to 15 years admitted with Pediatric AHO across two centers from 2008 to 2017. Demographic data, features of presentation, investigations, management, and complications were collected. Incidence was calculated from census data. Data were compared with our osteomyelitis database from the previous decade. (1). RESULTS: 796 cases were identified. The incidence was 18 per 100,000 per annum. The average age was 7.7 years. Pasifika and Maori children are overrepresented (57%). 370 children (51%) came from low socioeconomic areas. Methicillin-sensitive Staphylococcus aureus was the most common pathogen (87%). Methicillin-resistant Staphylococcus aureus (MRSA) rates are low (4.4%). Forty-four (5.5%) children were admitted to the Pediatric Intensive Care Unit (PICU) with 9% mortality. The mean duration of antibiotics was 40 days. 325 children (41%) had surgery. Chronic infection has increased from 1.7% to 5.7%. CONCLUSIONS: NZ has high rates of AHO, however, the incidence has decreased from the previous decade. Males, those in low socioeconomic areas, Pasifika and Maori have high disease burden. The use of MRI as a diagnostic modality has increased. Future studies should focus on improving treatment via prospective analysis and reporting long-term morbidity to improve outcomes for children with severe disease and reduce rates of chronic infection.

Microbiology of septic arthritis in young Auckland children.

BACKGROUND: Kingella kingae is an important cause of septic arthritis in young children, with modern laboratory methods leading to increased detection. Prevalence of this pathogen in New Zealand, where there are high rates of childhood infections due to Staphylococcus aureus and Streptococcus pyogenes, is not known. METHODS: We conducted a retrospective review of children <5 years with septic arthritis (without osteomyelitis) at a tertiary children's hospital in Auckland, over 10 years (2005-2014). Data were collected on demographics, microbiology, clinical presentation, investigations and management. RESULTS: Of the 68 cases of septic arthritis, 57 (83.8%) occurred in children aged <24 months. Among those <3 months, Streptococcus agalactiae (Group B streptococcus) was predominant (45.5% of 11 cases), followed by S. aureus (36.4%). The most common pathogen in those 3 to <12 months was Streptococcus pneumoniae (38.5% of 13 cases). In children aged 12 to <24 months, K. kingae was most common (30.3% of 33 cases). Of the 12 cases of K. kingae, 91.7% were identified from synovial fluid culture. All K. kingae isolates were susceptible to amoxicillin. CONCLUSIONS: K. kingae is the leading pathogen in septic arthritis in New Zealand children aged 12 to <24 months. Routine inoculation of synovial fluid into blood culture bottles at time of sample collection, in addition to use of polymerase chain reaction methods, should be encouraged to improve detection rates. For infants and preschool children presenting with single joint septic arthritis, empiric antibiotics should include cover for S. aureus and K. kingae.

How Do Complications Within the First 30 days after Spinal Deformity Surgery in Children with Cerebral Palsy Affect Length of Stay?

BACKGROUND: Surgery for spinal deformity in patients with cerebral palsy is reported to have high perioperative complication rates. However, minor complications are not generally reported and the influence of the varied severity of complications on length of stay is not known. Understanding the risk factors for both minor and major perioperative complications and their effect on length of stay is important information for clinicians who seek to improve care for this group of children. QUESTIONS/PURPOSES: (1) What is the prevalence of postoperative complications in the first 30 days after surgery for spinal deformity in a New Zealand national cohort of children with cerebral palsy using the Clavien-Dindo classification? (2) What are the patient and operative predictive risk factors for minor and major perioperative complications? (3) What is the effect of year of operation on risk of minor and major perioperative complications? (4) What is the effect of perioperative complications on length of stay? METHODS: We conducted a retrospective cohort study, identifying all children in New Zealand with a confirmed diagnosis of cerebral palsy who had surgery for a spinal deformity from January 1997 to January 2018. Two hundred-three patients with cerebral palsy (102 boys) were surgically treated for a spinal deformity, at a mean age of 14 ± 3 years, at one of three centers in New Zealand. Six children had Gross Motor Function Classification System Level II or III, 66 had Gross Motor Function Classification System Level IV, and 131 had Gross Motor Function Classification System Level V. Thirty-day perioperative complications were extracted from the patients' health records and classified according to the Clavien-Dindo system. Univariate and multivariate analyses were performed to identify patient and operative risk factors for complications, and the effect on length of stay. RESULTS: In all, 85% of patients experienced at least one perioperative complication. There were 300 Clavien-Dindo Grade I complications in 141 patients, 156 Clavien-Dindo Grade II complications in 102 patients, 25 Clavien-Dindo Grade III complications in 22 patients, 29 Clavien-Dindo Grade IV complications in 28 patients, and one Clavien-Dindo Grade V complication (death; 0.5%). Univariate analysis showed that multiple independent factors, Gross Motor Function Classification System Level V ability (odds ratio 2.13 [95% confidence interval 1.15 to 3.95]; p = 0.02), seizure disorder (OR 2.27 [95% CI 1.20 to 4.32]; p < 0.01), preoperative Cobb angle of greater than 70° (OR 2.40 [95% CI 1.20 to 4.78]; p < 0.01), and anterior approach to surgery (OR 3.29 [95% CI 1.21 to 8.90]; p = 0.02), were associated with Grade I complications but, of these factors, only the presence of a seizure disorder (OR 2.27 [95% CI 1.20 to 4.32]; p < 0.01) was associated with Grade I complications on multivariate analysis. Previous recurrent respiratory infections predicted an increased risk of Clavien-Dindo Grade II complications (OR 3.6 [95% CI 1.81 to 7.0]; p = 0.03). The presence of a feeding gastrostomy was associated with an increased risk of Clavien-Dindo Grade IV complications (OR 2.6 [95% CI 1.19 to 5.87]; p = 0.02). The year of operation did not influence the frequency of any grade of complication, but the presence of any complication led to an increased length of stay. CONCLUSION: Overall, 85% of patients with cerebral palsy had at least one complication after spinal deformity surgery and 25% had major complications (Grades III, IV, and V), with proportionate increases in the postoperative length of stay. Patient-specific factors aid in the identification of complication risk. LEVEL OF EVIDENCE: Level II, prognostic study.

Temporoparietal Fascial Flap for Soft Tissue Reconstruction of Pediatric and Young Adult Foot Defects: A Case Series.

Soft tissue defects of the foot due to trauma, infection, or malignancy are common and present a reconstructive challenge, as the foot requires specialized tissue that is thin, supple, yet durable enough to support the high demand of its function. The temporoparietal fascial flap, based on the superficial temporal artery and vein, is a reliable and versatile flap that possesses all these advantages. We present a case series detailing our experience with this flap for reconstruction of post-traumatic soft tissue defects of the foot in 4 patients (3 children and 1 young adult) with 5-year follow-up data. All patients were able to use the foot normally again to full capacity and wear normal footwear. They were also satisfied with the aesthetic outcome of the reconstruction and well-concealed donor site. This series highlights the success of this flap in providing excellent functional and aesthetic coverage for soft tissue foot defects in children and young adults, with minimal donor site morbidity.

Mutations Preventing Regulated Exon Skipping in MET Cause Osteofibrous Dysplasia.

The periosteum contributes to bone repair and maintenance of cortical bone mass. In contrast to the understanding of bone development within the epiphyseal growth plate, factors that regulate periosteal osteogenesis have not been studied as intensively. Osteofibrous dysplasia (OFD) is a congenital disorder of osteogenesis and is typically sporadic and characterized by radiolucent lesions affecting the cortical bone immediately under the periosteum of the tibia and fibula. We identified germline mutations in MET, encoding a receptor tyrosine kinase, that segregate with an autosomal-dominant form of OFD in three families and a mutation in a fourth affected subject from a simplex family and with bilateral disease. Mutations identified in all families with dominant inheritance and in the one simplex subject with bilateral disease abolished the splice inclusion of exon 14 in MET transcripts, which resulted in a MET receptor (MET(Δ14)) lacking a cytoplasmic juxtamembrane domain. Splice exclusion of this domain occurs during normal embryonic development, and forced induction of this exon-exclusion event retarded osteoblastic differentiation in vitro and inhibited bone-matrix mineralization. In an additional subject with unilateral OFD, we identified a somatic MET mutation, also affecting exon 14, that substituted a tyrosine residue critical for MET receptor turnover and, as in the case of the MET(Δ14) mutations, had a stabilizing effect on the mature protein. Taken together, these data show that aberrant MET regulation via the juxtamembrane domain subverts core MET receptor functions that regulate osteogenesis within cortical diaphyseal bone.

Pediatric Tibial Osteomyelitis.

BACKGROUND: Osteomyelitis shows a strong predilection for the tibia in the pediatric population and is a significant source of complications. The purpose of this article is to retrospectively review a large series of pediatric patients with tibial osteomyelitis. We compare our experience with that in the literature to determine any factors that may aid diagnosis and/or improve treatment outcomes. METHODS: A 10-year retrospective review was performed of clinical records of all cases of pediatric tibial osteomyelitis managed at the 2 children's orthopaedic departments in the Auckland region. The Osteomyelitis Database was used to identify all cases between 1997 and 2007, at Starship Children's Hospital, and 1998 and 2008 at Middlemore's Kids First Hospital. RESULTS: One hundred ninety-one patients fulfilled the inclusion criteria, and had a review of clinical notes and relevant investigations. The average duration of symptoms before presentation to hospital was 5.7 days. Less than 40% of patients had a recent episode of trauma. Almost 60% of patients could not bear weight on admission. Over 40% of patients had a temperature above 38°C. Erythrocyte sedimentation rate was elevated in 78% and the C-reactive protein was elevated in 90% of patients. In total, 42% of blood cultures and almost 75% of tissue cultures were positive, with Staphylococcus aureus being the most commonly cultured organism. X-rays, bone scans, and magnetic resonance imaging were all used to aid the diagnosis. About 43% of patients had surgery. Treatment length was an average of 2 weeks 6 days of intravenous antibiotics followed by 3 weeks 2 days of oral treatment. Six postsurgical complications and 46 readmissions were noted: 25 for relapse, with the remainder due to social and antibiotic-associated complications. CONCLUSIONS: Although generally diagnosed on presentation, pediatric tibial osteomyelitis can require more sophisticated investigations and prolonged management. Treatment with intravenous and oral antibiotics and surgical debridement where indicated can lead to a good clinical outcome, although complications are often noted. LEVEL OF EVIDENCE: Level IV-Prognostic study.

Pediatric Humeral Osteomyelitis.

BACKGROUND: Osteomyelitis is a common problem among the pediatric population. The humerus is the most commonly affected bone in the upper limb; however, there are relatively few series in the literature. This article retrospectively reviews a large number of cases of pediatric humeral osteomyelitis. We aim to further define the disease and its clinical course to aid in improved treatment. METHODS: A 10-year retrospective review was performed of clinical records of pediatric humeral osteomyelitis at the 2 children's orthopaedic departments in the Auckland region. The Osteomyelitis Database was used to identify all cases between 1997 and 2007 at Starship Children's Hospital, and 1998 and 2008 at Middlemore's Kidz First Hospital. RESULTS: Forty-nine patients were identified. Sixty-one percent were male with an average age of 4.2 years. Maori and Pacific Islanders were overrepresented. Seventy-eight percent were not using the limb, 70% complained of pain. Only 55% were febrile. White cell count, erythrocyte sedimentation rate, and C-reactive protein raised in 73%, 74%, and 79% of cases, respectively. X-ray, bone scintigraphy, and particularly magnetic resonance imaging were useful in radiologic diagnosis. Blood and tissue cultures revealed Staphylococcus aureus as the most common organism; there were 2 cases of community-acquired methicillin-resistant S. aureus. The distal humerus was more commonly affected. Fifty-three percent required surgery. Antibiotic therapy averaged 2.7 weeks intravenous and 2.6 weeks of oral therapy. There were 7 cases with adjacent septic arthritis, which had higher inflammatory markers. Major complications included 2 multiorgan failure and 1 growth disturbance. CONCLUSIONS: Humeral osteomyelitis can be diagnosed with an appropriate history, clinical examination, and investigations. One should be aware of concurrent septic arthritis and be prepared to treat this urgently. Those children with septic arthritis were not using the limb and had higher inflammatory markers. Treatment with intravenous and oral antibiotics and surgical debridement/washout if indicated can lead to good clinical outcomes with minimal complications. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Pediatric Acute Hematogenous Osteomyelitis.

BACKGROUND: Osteomyelitis continues to be a significant problem among the New Zealand pediatric population. We present a large series of acute hematogenous osteomyelitis (AHO) cases, with the aim to identify any changing trends and guide successful management of the disease. METHODS: A 10-year retrospective review was performed of clinical records of children with AHO at the 2 children's orthopaedic departments in the Auckland region. Cases were identified from Starship Children's Hospital between 1997 and 2007 and Middlemore's Kidz First Hospital between 1998 and 2008. RESULTS: A total of 813 cases of pediatric AHO were identified. The incidence was 1:4000, which was decreasing over the 10-year period. There was a male predominance and New Zealand (NZ) Maori and Pacific Islanders were overrepresented. The diagnosis was made clinically in 27%, radiographically in 66%, and surgically in 7%. The most common pathogen was Staphylococcus aureus and the incidence of methicillin-resistant S. aureus was low (2%). The average length of antibiotic treatment was 44 days and 44% required surgery. This produced a recurrence rate of only 7% and a 15% treatment-related complication rate. CONCLUSIONS: In the New Zealand population, the incidence of AHO remains high with NZ Maori and Pacific Islanders overrepresented. The predominant pathogen remains S. aureus and our population has a very low incidence of methicillin-resistant S. aureus; flucloxacillin remains a good choice for empiric treatment in our population. Our rate of relapse and subsequent chronic osteomyelitis is low. This could be explained by traditionally longer antibiotic courses; however, this may also lead to increased treatment-related complications. Through prompt and accurate diagnosis with the aid of laboratory and radiologic tests and effective treatment with appropriate antibiotics (guided by local pathogen sensitivities) and surgical treatment when indicated, AHO can be well managed with minimal severe complications. LEVEL OF EVIDENCE: Level IV-retrospective case series.

Septic arthritis and acute rheumatic fever in children: the diagnostic value of serological inflammatory markers.

INTRODUCTION: Joint pain and raised inflammatory markers are features of both acute rheumatic fever (ARF) and septic arthritis, often posing a diagnostic challenge to clinicians. Important differences in the presenting serological inflammatory marker profile may assist patient diagnosis, however, as clinical experience suggests that ARF is associated with a higher erythrocyte sedimentation rate (ESR), whereas other serological markers may be similarly elevated in these 2 conditions. OBJECTIVE: The goal of this study was to determine the diagnostic value of serological inflammatory markers and white cell count (WCC) in children presenting with acute joint pain secondary to ARF or septic arthritis. METHODS: Data were obtained from the Auckland regional rheumatic fever database and hospital computer records between 2005 and 2012. Records of all patients under the age of 16 years who were admitted with a new diagnosis of ARF or septic arthritis were analyzed. The diagnosis of ARF was defined on the basis of the New Zealand modification of the Jones Criteria, and the diagnosis of septic arthritis was defined on the basis of joint fluid cytology and culture. Baseline characteristics, serological inflammatory markers, and serum WCC were compared between the ARF and septic arthritis patient groups. RESULTS: Children with ARF displayed significantly higher ESR, higher serum C-reactive protein, and lower serum WCC than children with septic arthritis on presentation to hospital. In children presenting with monoarthritis, an ESR>64.5, serum WCC<12.1×109/L, and age above 8.5 years were found to be significant independent predictors of ARF. Children with all 3 predictors had a 71% risk for ARF and a 29% risk for septic arthritis. A significant proportion (30%) of children with the final diagnosis of ARF initially presented with monoarthritis; 14% of these children (5/34) had received nonsteroidal anti-inflammatory medication before hospital presentation, and 74% of these children (25/34) had abnormal echocardiograms on admission. CONCLUSIONS: ARF and septic arthritis are important diagnoses to consider in children presenting with acute joint pain in New Zealand. A significant proportion of patients with ARF initially present with acute monoarthritis. Serological inflammatory markers and WCC on presentation differ significantly between children with ARF and septic arthritis.

Methods to Reduce Cost of Treatment in Childhood Bone and Joint Infection: A Systematic Review.

BACKGROUND: Childhood bone and joint infection (BJI) is a potentially severe disease with consequences for growth and development. Critically unwell children may require prolonged hospitalization and multiple surgeries. Acknowledging rising healthcare costs and the financial impact of illness on caregivers, increased efforts are required to optimize treatment. This systematic review aims to characterize existing costs of hospital care and summarize strategies, which reduce treatment expense. METHODS: A systematic review of the literature was performed from January 1, 1980, to January 31, 2024. Data were extracted on hospitalization costs for pediatric BJI by decade and global region. Results have been converted to cost per day in US dollars with purchase parity for 2023. Studies reporting innovations in clinical care to reduce length of stay (LOS) and simplify treatment were identified. Studies trialing shorter antibiotic treatment were only included if they specifically reported changes in LOS. RESULTS: Twenty-three studies met inclusion criteria; of these, a daily hospitalization cost could be derived from 7 publications. Overall hospitalization cost and inpatient charges rose steeply from the 1990s to the 2020s. By contrast, average LOS seems to have decreased. Cost per day was higher in the United States than in Europe and higher for cases with confirmed methicillin-resistant Staphylococcus aureus. Sixteen studies report innovations to optimize care. For studies where reduced LOS was achieved, early magnetic resonance imaging with immediate transfer to theater when necessary and discharge on oral antibiotics were consistent features. CONCLUSION: Rising costs of hospital care and economic consequences for families can be mitigated by simplifying treatment for childhood BJI. Hospitals that adopt protocols for early advanced imaging and oral antibiotic switch may provide satisfactory clinical outcomes at lower cost. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

In Vitro Cell Surface Marker Expression on Mesenchymal Stem Cell Cultures does not Reflect Their Ex Vivo Phenotype.

Cell surface marker expression is one of the criteria for defining human mesenchymal stem or stromal cells (MSC) in vitro. However, it is unclear if expression of markers including CD73 and CD90 reflects the in vivo origin of cultured cells. We evaluated expression of 15 putative MSC markers in primary cultured cells from periosteum and cartilage to determine whether expression of these markers reflects either the differentiation state of cultured cells or the self-renewal of in vivo populations. Cultured cells had universal and consistent expression of various putative stem cell markers including > 95% expression CD73, CD90 and PDPN in both periosteal and cartilage cultures. Altering the culture surface with extracellular matrix coatings had minimal effect on cell surface marker expression. Osteogenic differentiation led to loss of CD106 and CD146 expression, however CD73 and CD90 were retained in > 90% of cells. We sorted freshly isolated periosteal populations capable of CFU-F formation on the basis of CD90 expression in combination with CD34, CD73 and CD26. All primary cultures universally expressed CD73 and CD90 and lacked CD34, irrespective of the expression of these markers ex vivo indicating phenotypic convergence in vitro. We conclude that markers including CD73 and CD90 are acquired in vitro in most 'mesenchymal' cells capable of expansion. Overall, we demonstrate that in vitro expression of many cell surface markers in plastic-adherent cultures is unrelated to their expression prior to culture.

Three solutions to a single problem: alternative casting frames for treating infantile idiopathic scoliosis.

STUDY DESIGN: This is a technique article discussing 3 alternative frames for casting children with infantile scoliosis. OBJECTIVE: To provide surgeons with alternatives to expensive specialized casting tables to allow local treatment of these children utilizing readily available materials present at most institutions. SUMMARY OF BACKGROUND: Casting for infantile scoliosis has become more popular as reports have shown promising results with this technique without the morbidity and complications associated with more invasive procedures. However, without a specialized casting table, treating these patients has been limited to a few centers throughout the country often causing patients to travel large distances to receive care. METHODS: Three different alternatives to commercially available casting frames are presented. Requirements, setup, and techniques are discussed. RESULTS: Each surgeon has had success with each of these frames. These provide adequate support and traction while allowing enough access to the trunk to apply a well-molded cast. CONCLUSIONS: Cotrel/Metha casting for infantile scoliosis can be accomplished without a specialized table using commonly available equipment.

A microbiology study on the wounds of pediatric patients undergoing spinal fusion for scoliosis.

PURPOSE: Surgical site infection is a significant complication in posterior spinal fusion for scoliosis in pediatric and adolescent patients. Current literature demonstrates a lack of consensus regarding best prophylactic systemic and topical antibiotic regimens for reducing infection rates. This study aims to identify which common microbes are present at particular locations in the spine, and whether these are covered by our current systemic and topical antibiotic prophylaxis regimens. METHODS: A prospective observational study at a National Children's Hospital was conducted on 21 consecutive patients who underwent elective surgery for spinal deformity. Swabs were taken from four layers of the spine, including the superficial skin surface at the start of the case (after surgical site preparation with povidone-iodine), the deep dermis, and the deep surgical bed at the end of exposure and again after the corrective maneuver prior to closure. At each layer, swabs were taken from the proximal, middle, and distal portion of the wound. Swabs were sent to the laboratory for culture and susceptibility testing. RESULTS: Thirteen (62%) of patients had positive microbial growth. Two microbes were identified, Staphylococcus epidermidis (9.5% of patients) and Cutibacterium acnes (Propionibacterium acnes) (52% of patients). 100% of these microbes were sensitive to cefazolin and vancomycin. 3% of patients had positive growth at the skin layer, 32% positive at the dermal layer, 17% positive after exposure, and 40% positive at the conclusion of the case (p = 0.006). No difference was observed in microbial presence in the upper thoracic, lower thoracic and lumbar spine. CONCLUSION: Despite adequate surgical site preparation and sterile procedure, microbial contamination remains abundant in the dermal layer and deeper in the spinal wound throughout the case.

Transfer Validity of Pediatric Supracondylar Humeral Fracture Pin Placement Practice on In-Theater Performance by Orthopedic Trainees Using an Augmented Reality Simulator: Protocol for a Pilot Interventional Cohort Study With a Retrospective Comparator Cohort.

BACKGROUND: Supracondylar humeral fractures (SCHF) are a common cause of orthopedic morbidity in pediatric populations across the world. The treatment of this fracture is likely one of the first procedures involving x-ray-guided wire insertion that trainee orthopedic surgeons will encounter in their career. Traditional surgical training methods of "see one, do one, teach one" are reliant on the presence of real-world cases and must be conducted within an operative environment. We have developed an augmented reality simulator that allows trainees to practice this procedure in a radiation-free environment at no extra risk to patients. OBJECTIVE: This study aims to examine whether training on a simulator in addition to traditional surgical training improves the in-theater performance of trainees. METHODS: This multicenter, interventional cohort study will involve orthopedic trainees from New Zealand in their first year of advanced training between 2019 and 2023. Advanced trainees with no simulator exposure who were in their first year in 2019-2021 will form the comparator cohort, while those in the years 2022-2023 will receive additional regular simulator training as the intervention cohort. The comparator cohort's performance in pediatric SCHF surgery will be retrospectively audited using routinely collected operative outcomes and parameters over a 6-month period. Data on the performance of the intervention cohorts will be collected in the same way over a comparable period. The data collected for both groups will be used to determine whether additional training with an augmented reality training shows improved real-world surgical outcomes compared to traditional surgical training. RESULTS: As of February 2022, a total of 8 retrospective comparator trainees have been recruited by email. The study is financially supported through an external grant from the Wishbone Orthopaedic Research Foundation of New Zealand (September 2021) and an internal research grant from the University of Otago (July 2021). CONCLUSIONS: This protocol has been approved by the University of Otago Health Ethics committee (reference HD21/087), and the study is due for completion in 2024. This protocol may assist other researchers conducting similar studies in the field. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12623000816651; https://tinyurl.com/mtdkecwb. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/38282.

Risk factors for distal construct failure in posterior spinal instrumented fusion for adolescent idiopathic scoliosis: a retrospective cohort study.

PURPOSE: To evaluate risk factors for distal construct failure (DCF) in posterior spinal instrumented fusion (PSIF) in adolescent idiopathic scoliosis (AIS). We hypothesise increased inferior angulation of the pedicle screw in the lowest instrumented vertebra (LIV) predisposes to failure and aim to find the critical angle that predisposes to failure. METHODS: A retrospective cohort study was performed on all patients who underwent PSIF for AIS at our institution from 2010 to 2020. On lateral radiographs, the angle between the superior endplate of the LIV was measured against its pedicle screw trajectory. Data on demographics, Cobb angle, Lenke classification, instrumentation density, rod protrusion from the most inferior screw, implants and reasons for revision were collected. RESULTS: Of 256 patients, 9 patients had DCF with 3 further failures post-revision, giving 12 cases to analyse. The DCF rate was 4.6%. The mean trajectory angle of DCF patients compared to non-DCF was 13.3° (95% CI 9.2° to 17.4°) vs. 7.6° (7.0° to 8.2°), p = 0.0002. The critical angle is less than 11° (p = 0.0076), OR 5.15. Lenke 5 and C curves, lower preoperative Cobb angle, titanium only rod constructs and one surgeon had higher failure rates. 9.6% of rods protruding less than 3 mm from its distal screw disengaged. CONCLUSION: Increased inferior trajectory of the LIV screw increases the rate of DCF; inferior trajectory greater than 11° predisposes to failure. Rod protrusion less than 3 mm from the distal screw increases rate of disengagement. LEVEL OF EVIDENCE: III.

Adolescent idiopathic scoliosis with concomitant spondylolysis: choice of fusion levels and evaluation of the outcomes obtained leaving the lytic level not instrumented.

PURPOSE: 7% of adolescent idiopathic scoliosis (AIS) patients also present with a pars defect. To date, there are no available data on the results of fusion ending proximal to a spondylolysis in the setting of AIS. The aim of this study was to analyze the outcomes of posterior spinal fusion (PSF) in this patient cohort, to investigate if maintaining the lytic segment unfused represents a safe option. METHODS: Retrospective review of all patients who received PSF for AIS, presented with a spondylolysis or spondylolisthesis and had a min. 2-year follow-up. Demographic data, instrumented levels, and preoperative radiographic data were collected. Mechanical complications, coronal or sagittal parameters, amount of slippage, and pain levels were evaluated. RESULTS: Data from 22 patients were available (age 14.4 ± 2.5 years), 18 Lenke 1-2 and 4 Lenke 3-6. 5 patients (24%) had an isthmic spondylolisthesis, all Meyerding I. The mean preoperative Cobb angle of the instrumented curves was 58 ± 13°. For 18 patients, the lowest instrumented vertebra (LIV) was the last touched vertebra (LTV); for 2, LIV was distal to the LTV; for 2, LIV was one level proximal to the LTV. The number of segments between the LIV and the lytic vertebra ranged from 1 to 6. At the last follow-up, no complications were observed. The residual curve below the instrumentation measured 8.5 ± 6.4°, the lordosis below the instrumented levels was 51.4 ± 13°. The magnitude of the isthmic spondylolisthesis remained constant for all included patients. Three patients reported minimal occasional low back pain. CONCLUSION: The LTV can be safely used as LIV when performing PSF for the management of AIS in patients with L5 spondylolysis.

Early results of total hip arthroplasty in patients with developmental dysplasia of the hip compared with patients with osteoarthritis.

We have investigated the results of primary total hip arthroplasty (THA) performed in patients with developmental dysplasia of the hip (DDH). Through the New Zealand Joint Registry, we identified all patients with DDH undergoing primary THA (n = 1205) and all patients with primary osteoarthritis (OA) undergoing primary THA (n = 40 589) between January 1, 1999, and December 31, 2008. Postoperative outcomes, baseline information, and operative characteristics were analyzed and compared between the DDH and the OA groups. There was no significant difference in Oxford Hip Score or revision rate between the 2 groups. Our results support THA as a successful surgical option in the management of degenerative arthritis in DDH, with comparable functional outcomes and revision rates to THA performed for primary OA.

Early results of total hip arthroplasty in patients with slipped upper femoral epiphysis compared with patients with osteoarthritis.

We have investigated the results of primary total hip arthroplasty (THA) performed in patients with slipped upper femoral epiphysis (SUFE). Through the New Zealand Joint Registry, we identified all patients with SUFE undergoing primary THA (n = 117) and all patients with primary osteoarthritis (OA) undergoing primary THA (n = 40 589) between January 1, 1999, and December 31, 2008. Baseline information, operative characteristics, and postoperative outcomes were analyzed and compared between the SUFE and the OA groups. There was no significant difference in postoperative Oxford Hip Score or revision rate between the 2 groups. Our results support THA as a successful surgical option in the management of degenerative arthritis in SUFE, with comparable functional outcomes and revision rates to THA performed for primary OA.

The Effect of the Type of Screw Fixation Used in the Treatment of Slipped Capital Femoral Epiphysis.

Background: Slipped capital femoral epiphysis (SCFE) remains among the most common hip disorders in the adolescent population. The management of SCFE remains controversial; however, the aim of fixation is to stabilize the physis and prevent further slippage. In situ fixation remains the gold standard; however, in the young population, it can lead to reduced femoral neck growth and complications such as leg length discrepancies. The ideal form of in situ fixation for mild to moderate SCFE would stabilize the slip and allow continued proximal femoral growth. This study aimed to determine if partially threaded screws allowed more neck growth than fully threaded screws. Methods: A retrospective review of the radiographs of all patients undergoing in situ fixation for SCFE using partially threaded and fully threaded screws. Measurements included neck length, neck-to-screw ratio, neck shaft angle, neck width, and articular-trochanteric distance. Parameters were compared over a two-year period to determine whether there was any difference in proximal femoral growth between the two types of screws. Results: Fully threaded screw neck length increased by 5 mm versus 5 mm for proximally threaded screws (P ≤ 0.001). No significant difference was observed between the two groups with respect to neck width, neck shaft angle, and articular-trochanteric distance. Conclusions: No difference was observed in proximal femoral growth. Regardless of which type of fixation is used, neck length continues to increase by approximately 3 mm per year.