Romain Olivier Pierre Dayer

Strontium Ranelate Treatment Improves Trabecular and Cortical Intrinsic Bone Tissue Quality, a Determinant of Bone Strength†

Beside its influence on determinants of bone strength (geometry, microarchitecture), which is likely to be related to a cellular effect, strontium ranelate improves bone tissue quality as evaluated by nanoindentation, increasing elastic modulus, hardness, and dissipated energy in vertebrae of rats treated for 104 wk with daily dose from 0 to 900 mg/kg.

Defective implant osseointegration under protein undernutrition: prevention by PTH or pamidronate

Protein deficiency is associated with impaired titanium osseointegration. We studied whether systemic treatment with PTH or pamidronate could influence the resistance to pull‐out of titanium rods implanted into rats proximal tibia under normal and isocaloric low protein intake. PTH or pamidronate prevented the deleterious effects of protein undernutrition on bone microarchitecture close to the implant and on mechanical fixation. PTH even significantly improved implant osseointegration.

Low Protein Intake Is Associated With Impaired Titanium Implant Osseointegration

Low protein intake is highly prevalent among orthopaedic elderly patients. We studied the effects of an isocaloric low protein diet on the resistance to pull‐out of titanium rods implanted into rats proximal tibia. Isocaloric low protein intake impairs titanium implant osseointegration, with a decreased strength needed to completely loose the implant and altered bone microarchitecture in its vicinity.

Pelvic fixation for neuromuscular scoliosis deformity correction

Pelvic fixation is most frequently indicated in the pediatric population for the treatment of neuromuscular scoliosis with significant pelvic obliquity. Neuromuscular scoliosis surgery is associated with a high risk of complications, and this is further increased by extension of fusion to the sacrum. Numerous techniques have been described for pelvic fixation associated with a long spine fusion each with its own set of specific benefits and risks. This article reviews the contemporary surgical techniques of pelvic fixation used to extend a spine fusion to the sacrum and pelvis focusing on the management of neuromuscular scoliosis, including their biomechanical rationale, results, and complications.

Possible association of Kingella kingae with infantile spondylodiscitis.

The course of the spondylodiscitis’ infantile form is characterized by a mild-to-moderate clinical and biologic inflammatory response. Unfortunately, blood and disk/vertebral aspiration cultures show a high percentage of negative results. However, detecting Kingella kingae DNA in the oropharynx provided reasonable suspicion, to our opinion, that this microorganism is responsible for the spondylodiscitis.

Calcitropic Hormones and IGF-I Are Influenced by Dietary Protein

Elderly men and women with protein deficiencies have low levels of circulating IGF-I, and it is likely this contributes to reduced bone formation and increased bone resorption. We hypothesized that calcitropic hormones are involved in this effect and are affected by dietary protein. We therefore investigated the influence of a low-protein diet on the PTH-1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] axis and IGF-I in rats, using pamidronate to block resorption that normally contributes to mineral homeostasis. We fed 6-month-old Sprague Dawley female rats isocaloric diets containing 2.5% or 15% casein for 2 wk. Pamidronate was then administered sc (0.6 mg/kg/) for 5 d. Blood samples were collected at different time points. Serum 1,25(OH)₂D₃, IGF-I, PTH, calcium, and phosphorus were determined in all rats; vertebral bone strength and histomorphometric analysis were performed in rats subject to the longest low-protein diets. We found 2 wk of low protein increased PTH levels, decreased 1,25(OH)₂D₃, calcium, and IGF-I, suggesting that increased PTH compensates for low-protein-induced decreases in 1,25(OH)₂D₃. Pamidronate augmented the increased PTH after 8 wk of low protein and prevented the 1,25(OH)₂D₃ decrease. IGF-I remained low. Protein malnutrition induced decreases in relative bone volume and trabecular thickness, which was prevented by pamidronate. Maximal load was reduced by protein restriction, but rescued by pamidronate. In summary, the low protein diet resulted in hyperparathyroidism, a reduction in circulating levels of IGF-I, and reduced 1,25(OH)₂D₃ despite hyperparathyroidism. Blocking resorption resulted in further increases in PTH and improved microarchitecture and biomechanical properties, irrespective of vitamin D status or protein intake.

Systemic Treatment with Strontium Ranelate Accelerates the Filling of a Bone Defect and Improves the Material Level Properties of the Healing Bone

Rapid bone defect filling with normal bone is a challenge in orthopaedics and dentistry. Strontium ranelate (SrRan) has been shown to in vitro decrease bone resorption and increase bone formation, and represents a potential agent with the capacity to accelerate bone defect filling. In this study, bone tibial defects of 2.5 mm in diameter were created in 6-month-old female rats orally fed SrRan (625 mg/kg/d; 5/7 days) or vehicle for 4, 8, or 12 weeks (10 rats per group per time point) from the time of surgery. Tibias were removed. Micro-architecture was determined by micro-computed tomography (µCT) and material level properties by nanoindentation analysis. µCT analysis showed that SrRan administration significantly improved microarchitecture of trabecular bone growing into the defect after 8 and 12 weeks of treatment compared to vehicle. SrRan treatment also accelerated the growth of cortical bone over the defect, but with different kinetics compared to trabecular bone, as the effects were already significant after 4 weeks. Nanoindentation analysis demonstrated that SrRan treatment significantly increased material level properties of both trabecular bone and cortical bone filling the defect compared to vehicle. SrRan accelerates the filling of bone defect by improving cortical and trabecular bone microarchitecture both quantitatively and qualitatively.

Tibial Aplasia-hypoplasia and Ectrodactyly in Monozygotic Twins With a Discordant Phenotype

Tibial hemimelia with ectrodactyly is reported for the first time in monozygotic female twins with a positive family history for limb anomalies. This very rare autosomal dominant condition is known to be associated with a highly variable phenotype, as illustrated by the distinct clinical presentations, despite identical genotype.

Primary epiphyseal or apophyseal subacute osteomyelitis in the pediatric population: a report of fourteen cases and a systematic review of the literature.

BACKGROUND Primary epiphyseal or apophyseal subacute osteomyelitis (PEASAO) is a rare condition that typically has mild symptoms and lack of a systemic reaction, according to opinions, case reports, and case series. We reviewed fourteen consecutive cases of PEASAO treated at our institution over a thirteen-year period to characterize this disorder. METHODS We retrospectively reviewed the medical records of all children and adolescents who had been surgically managed for PEASAO at our institution from January 2000 to December 2012. A systematic review of the literature was also performed to identify trends in causative organisms and formulate evidence-based recommendations for diagnosis and treatment. RESULTS Fourteen children (median age, 27.8 months) with PEASAO were included in the study. Fever (rectal temperature, >38°C) was present at admission in two children, C-reactive protein was within the normal range (<10 mg/dL) in eleven, the erythrocyte sedimentation rate was >20 mm/hr in eight, and the white blood-cell count was normal in all. The pathogen was not identified on blood cultures in any child and was identified on classical cultures of bone samples in only one. Use of PCR (polymerase chain reaction) assays allowed the pathogen to be identified in an additional eight children. The pathogen was Kingella kingae in eight and methicillin-sensitive Staphylococcus aureus in one. DISCUSSION The use of organism-specific real-time PCR assays markedly improves the detection rate of the pathogen responsible for PEASAO, and K. kingae is the most commonly detected pathogen. The literature highlights a biphasic age distribution of PEASAO in children. The infantile form affects children from one to less than four years of age, accounting for approximately 75% of all PEASAO cases. The second form, in older children, is more likely to be associated with fever and systemic symptoms. The femur and the tibia are the most commonly affected long bones. Laboratory data are usually noncontributory for diagnosing PEASAO, and blood cultures are often sterile. Although K. kingae is the most commonly detected microorganism in children less than four years of age, S. aureus is responsible for most PEASAO in older children. Antibiotic treatment is usually sufficient to eradicate the pathogen.

Conditions found among pediatric survivors during the early response to natural disaster: a prospective case study

Background: Major natural disasters may provoke a mass casualty situation, and children tend to represent an important proportion of the victims. The purpose of this study was to prospectively record medical conditions presented by pediatric survivors of a major natural disaster to determine the type of medical specialists most needed during the acute phase of relief response. Methods: After the 2010 Haiti earthquake, age, sex, date of presentation, diagnosis, and treatment provided were prospectively recorded for all patients less than 18 years old treated by a medical relief team. Patients were then allocated to 1 of the 2 groups: surgical (traumatism or surgical disorder) and medical (medical disorder). Medical activity lasted for 43 days. Results: Four hundred seventy-one of the 796 treated patients were less than 18 years old. Two hundred forty-four (52%) were assigned to the surgical group and 227 (48%) to the medical group. As there was a substantial decrease in the number of new surgical patients registered on day 11 of activity, we arbitrarily defined an early period (until day 10 of activity) and a late period (beginning on day 11 of activity). Data obtained from the 147 new patients registered during the early period revealed 134 (91%) surgical patients and 13 (9%) medical patients. Eighty-eight percent of patients needed specialized care for traumatic orthopaedic lesions, and procedures under anesthesia or sedation were mainly (98%) performed for traumatic conditions. Data obtained for the 324 new patients registered during the late period revealed 110 (34%) surgical patients and 214 (66%) medical patients. There was a switch from high surgical needs to more routine medical and surgical care, with less procedures (88%) for the treatment of traumatic lesions. Conclusions: Pediatric orthopaedic surgeons have a major role to play in the acute phase of relief response to potentially minimize long-term physical and psychosocial disability associated with these complex injuries in growing patients. Level of Evidence: Economic or decision analyses, level II.