The proximal vastus lateralis flap: An anatomical and radiological study.

INTRODUCTION: Soft-tissue reconstruction following acetabular or proximal femur resection for bone tumors is challenging. The vastus lateralis flap has been proposed as an advancement or rotational flap to cover soft-tissue defects for such locoregional indications. We performed an anatomical and a radiological study to assess the vascularization of the proximal vastus lateralis muscle achieved through the transverse branch of the lateral circumflex femoral artery in order to decrease the morbidity of the classical flap retrieval technique. MATERIAL AND METHODS: Five fresh adult cadavers were dissected bilaterally. Each vastus lateralis dissection was prealably injected with contrast-media agent through the lateral circumflex artery and CT scan images was recorded. A descriptive and an analytical study were carried out. RESULTS: The median length and width of the entire muscle were 31.2cm (Q1-Q3: 29.7-33.3) and 12.7cm (Q1-Q3: 7.0-14.9), respectively; the median surface area of the entire vastus lateralis muscle was 282cm2 (Q1-Q3: 172.6-455.6) cm2. The median length and width of the perfused area were 13.3cm (Q1-Q3: 12.3-16.6) and 9.4cm (Q1-Q3: 6.9-8.8) cm, respectively; the median surface of the perfused area was 89.4cm2 (Q1-Q3: 67.4-110.5) cm2. The mean length of the pedicle measured on the CT scan was 6.3cm (95% CI: 5.5-7.1). CONCLUSION: The proximal vastus lateralis flap as a pedicled muscular flap supplied by the transverse branch of the lateral circumflex femoral artery is a muscular flap that can be used by reconstructive and orthopaedic surgeons to repair soft-tissue defects around the hip joint without undue damage to the functional apparatus of the knee.

Micro-finite-element method to assess elastic properties of trabecular bone at micro- and macroscopic level.

OBJECTIVE OF THE STUDY: The objective of the present study is to assess the mechanical behavior of trabecular bone based on microCT imaging and micro-finite-element analysis. In this way two methods are detailed: (i) direct determination of macroscopic elastic property of trabecular bone; (ii) inverse approach to assess mechanical properties of trabecular bone tissue. PATIENTS: Thirty-five females and seven males (forty-two subjects) mean aged (±SD) 80±11.7 years from hospitals of Assistance publique-Hôpitaux de Paris (AP-HP) diagnosed with osteoporosis following a femoral neck fracture due to a fall from standing were included in this study. MATERIALS AND METHODS: Fractured heads were collected during hip replacement surgery. Standardized bone cores were removed from the femoral head's equator by a trephine in a water bath. MicroCT images acquisition and analysis were performed with CTan® software and bone volume fraction was then determined. Micro-finite-element simulations were per-formed using Abaqus 6.9-2® software in order to determine the macroscopic mechanical behaviour of the trabecular bone. After microCT acquisition, a longitudinal compression test was performed and the experimental macroscopic Young's Modulus was extracted. An inverse approach based on the whole trabecular bone's mechanical response and micro-finite-element analysis was performed to determine microscopic mechanical properties of trabecular bone. RESULTS: In the present study, elasticity of the tissue was shown to be similar to that of healthy tissue but with a lower yield stress. CONCLUSION: Classical histomorphometric analysis form microCT imaging associated with an inverse micro-finite-element method allowed to assess microscopic mechanical trabecular bone parameters.

Factors associated with hospital admission and adverse outcome for COVID-19: Role of social factors and medical care.

BACKGROUND: Beyond sex, age, and various comorbidities, geographical origin and socioeconomic deprivation are associated with Coronavirus Disease (COVID-19) morbidity and mortality in the general population. We aimed to assess factors associated with severe forms of COVID-19 after a hospital emergency department visit, focusing on socioeconomic factors. METHODS: Patients with laboratory-confirmed COVID-19 attending the emergency department of Béclère Hospital (France) in March-April 2020 were included. Postal addresses were used to obtain two geographical deprivation indices at the neighborhood level. Factors associated with hospitalization and factors associated with adverse outcomes, i.e. mechanical ventilation or death, were studied using logistic and Cox analyses, respectively. RESULTS: Among 399 included patients, 321 were hospitalized. Neither geographical origin nor socioeconomic deprivation was associated with any of the outcomes. Being male, older, overweight or obese, diabetic, or having a neuropsychiatric disorder were independent risk factors for hospitalization. Among 296 patients hospitalized at Béclère Hospital, 91 experienced an adverse outcome. Older age, being overweight or obese, desaturation and extent of chest CT scan lesions>25% at admission (aHR: 2.2 [95% CI: 1.3-3.5]) and higher peak CRP levels and acute kidney failure (aHR: 2.0 [1.2-3.3]) during follow-up were independently associated with adverse outcomes, whereas treatment with hydrocortisone reduced the risk of mechanical ventilation or death by half (aHR: 0.5 [0.3-0.8]). CONCLUSION: No association between geographical origin or socioeconomic deprivation and the occurrence of a severe form of COVID-19 was observed in our population after arrival to the emergency department. Empirical corticosteroid use with hydrocortisone had a strong protective impact.

Human dentin characteristics of patients with osteogenesis imperfecta: insights into collagen-based biomaterials.

Osteogenesis imperfecta (OI), also known as "brittle bone disease", is a rare genetic disorder of the skeleton, whose most benign form I corresponds to autosomal dominant mutations in the genes encoding type I collagen (COLA1, COLA2). Several associated skeletal manifestations are often observed but, surprisingly, while dentin defects often reflect genetic bone disorders, about half of OI patients have no obvious oral manifestations. Here, we investigated the collagen, mineral and mechanical properties of dentin from deciduous teeth collected from patients with mild form of OI and displaying no obvious clinical signs of dentinogenesis imperfecta. For the first time, an increase in the hardness of OI dentin associated with an increase in mineral content compared to healthy patients was reported. In addition, OI altered the tissue characteristics of the dentin-enamel junction but the interfacial gradient was preserved. The impact of changes in molecular structure due to mutations in OI was assessed by Raman microspectroscopy. Our results highlighted a change in the hydroxyproline-proline ratio in direct association with collagen mineralization. Our findings suggest that the evaluation of teeth could be an important aid for mild types of OI that are often difficult to diagnose clinically and provide experimental evidence that hydroxyproline content should be considered in future studies on collagen-based biomaterials.

Surgical treatment of a 180° thoracolumbar fixed kyphosis in a young achondroplastic patient: a one-stage "in situ" combined fusion and spinal cord translocation.

An achondroplastic patient with a thoracolumbar kyphosis was first seen at the age of 16 at our institution. His only concern at that time was the aesthetic implication of his deformity. His physical examination was normal except for loss of the neurologic reflexes in the lower limbs. The radiographs showed a fixed 180° thoracolumbar kyphosis with correct frontal and sagittal balances. No spinal cord anomaly was found on MRI. Two years later, he developed a progressive neurogenic claudication of the lower limbs. He was still neurologically intact at rest. The MRI showed an abnormal central spinal cord signal in front of the apex of the kyphosis associated with the narrow congenital spinal canal. In regards to this progressive neurological worsening, a surgical treatment was decided. We decided to perform a front and back arthrodesis combined with a spinal cord decompression without reduction of the deformity. A five-level hemilaminotomy was performed with a posterior approach at the kyphosis deformity. The spinal cord was individualised onto 10 cm and the left nerve roots were isolated. A decancellation osteotomy of the three apex vertebrae and a disc excision were performed. The posterior aspect of the vertebral body was then translated forward 2 cm and in association with the spinal cord. Two nerve roots were severed laterally to approach the anterior part of the kyphosis and a peroneal strut graft was inlayed anterolaterally. A complementary anterior and a right posterolateral fusion was made with cancellous bone. The patient was immobilised in a cast for 3 months relayed by a thoracolumbosacral orthosis for 6 months. At 3 years follow-up, the neurogenic claudication had disappeared. No worsening of the kyphosis was observed. His only complaint is violent electric shock in the lower limbs with any external sudden pressure on the spinal cord in the area uncovered by bone.

Microscale mechanical and mineral heterogeneity of human cortical bone governs osteoclast activity.

Human cortical bone permanently remodels itself resulting in a haversian microstructure with heterogeneous mechanical and mineral properties. Remodeling is carried out by a subtle equilibrium between bone formation by osteoblasts and bone degradation by osteoclasts. The mechanisms regulating osteoclast activity were studied using easy access supports whose homogeneous microstructures differ from human bone microstructure. In the current study, we show that human osteoclasts resorb human cortical bone non-randomly with respect to this specific human bone microstructural heterogeneity. The characterization of this new resorption profile demonstrates that osteoclasts preferentially resorb particular osteons that have weak mechanical properties and mineral contents and that contain small hydroxyapatite crystals with a high carbonate content. Therefore, the influence of human bone microstructure heterogeneity on osteoclast activity could be a key parameter for osteoclast behaviour, for both in vitro and clinical studies.

Metacarpal lengthening in children: comparison of three different techniques in 15 consecutive cases.

Metacarpal lengthening is a useful procedure to address hand deficiencies in children. In this study, we aimed to compare the results of three different techniques from one consecutive clinical series of hand deficiencies. A total of 15 metacarpal lengthenings have been performed in 12 children aged from 9 to 14 years. The callotasis technique was used in seven cases, the two-stage distraction-graft technique in four cases and the single-stage lengthening in four cases. All the metacarpals healed with bone. The lengthening obtained was a mean of 13 mm (range 8-21 mm), a mean of 22 mm (range 13-32 mm) and a mean of 12 mm (range 9-15 mm), respectively, in the three different techniques. The healing index was longer for callotasis (81 days/cm) compared with the other techniques (41 days/cm and 46 days/cm, respectively). We observed one case of fracture after callotasis and one after distraction-graft. One patient underwent tenolysis of the extensor mechanism after single-stage lengthening. In conclusion, distraction graft and single-stage lengthening may be valuable alternatives to callotasis. LEVEL OF EVIDENCE: IV; therapeutic study; multi-case series.

[Evaluation of surgical skills of French ophthalmology, orthopedic and gastrointestinal surgery residents: Current status and perspectives]. / Évaluation des compétences techniques des internes de chirurgie ophtalmologique, orthopédique et digestive français : état actuel et perspectives.

The purpose of this study was to evaluate the need for nationwide assessment of surgical skills during residency, and to define ideal methods for assessment in three surgical disciplines: ophthalmology, orthopedics and gastrointestinal surgery. Three online questionnaires were sent by e-mail to 784 residents, fellows and hospital practitioners, and 119 university hospital physican-professors. Questionnaires focused on current assessment methods at the regional level, the roles of the surveyed population in these evaluations, potential obstacles to their development and the most relevant methods for practical evaluations. Nine hundred and three questionnaires were sent; 355 participants replied (response rate: 39%). The establishment of systematic assessment seemed necessary to over 90% of the survey population, and this opinion was equitably distributed among all three specialties. Over 60% of respondents felt that current assessment procedures were not satisfactory. In all three specialties, the ideal evaluation method proposed was a real patient procedure. This "in vivo" evaluation was considered applicable in 80% of cases, potential barriers to its development being the resident's anxiety, medical-legal reasons and the lack of objective criteria. The ideal timing of these assessments was bi-annual. Implementation of surgical skills assessment during residency seems necessary. The survey population appears dissatisfied with current arrangements. A step-by-step evaluation combining surgical simulations, animal training and live patient procedures may be appropriate.

External fixation of the thalamic portion of a fractured calcaneus: a new surgical technique.

The optimal treatment for intra-articular calcaneus fractures remains controversial, despite internal fixation techniques providing good results. The major point of contention is the need to reconstruct the overall morphology versus to restore the anatomy of the subtalar joint perfectly. We will describe a two-stage technique for treating intra-articular calcaneus fractures in which the primary fracture line goes through the thalamic fragment. The first procedure focuses on the overall morphology by restoring the height and length with osteotaxis being accomplished with a medial external fixator. The second procedure consists of internal fixation through a minimally invasive lateral approach to restore the anatomy of the articular facets. Any defects are filled with injectable bone substitute. This novel technique is compared to the complication rates and radiology and anatomy outcomes in published studies. This two-stage surgical technique reduces the length of hospital stays and the number of complications.

The rat model of femur fracture for bone and mineral research: An improved description of expected comminution, quantity of soft callus and incidence of complications.

OBJECTIVES: One commonly used rat fracture model for bone and mineral research is a closed mid-shaft femur fracture as described by Bonnarens in 1984. Initially, this model was believed to create very reproducible fractures. However, there have been frequent reports of comminution and varying rates of complication. Given the importance of precise anticipation of those characteristics in laboratory research, we aimed to precisely estimate the rate of comminution, its importance and its effect on the amount of soft callus created. Furthermore, we aimed to precisely report the rate of complications such as death and infection. METHODS: We tested a rat model of femoral fracture on 84 rats based on Bonnarens' original description. We used a proximal approach with trochanterotomy to insert the pin, a drop tower to create the fracture and a high-resolution fluoroscopic imager to detect the comminution. We weighed the soft callus on day seven and compared the soft callus parameters with the comminution status. RESULTS: The mean operating time was 34.8 minutes (sd 9.8). The fracture was usable (transverse, mid-shaft, without significant comminution and with displacement < 1 mm) in 74 animals (88%). Of these 74 usable fractures, slight comminution was detected in 47 (63%). In 50 animals who underwent callus manipulation, slight comminution (n = 32) was statistically correlated to the amount of early callus created (r = 0.35, p = 0.015). Two complications occurred: one death and one deep infection. CONCLUSIONS: We propose an accurate description of comminution and complications in order to improve experiments on rat femur fracture model in the field of laboratory research. Cite this article: Bone Joint Res 2013;2:149-54.

Primary arthroscopic synovectomy for pigmented villo-nodular synovitis of the knee: recurrence rate and functional outcomes after a mean follow-up of seven years.

BACKGROUND: Pigmented villo-nodular synovitis (PVNS) is an uncommon proliferative condition of the synovial membrane that chiefly affects the knee. Arthroscopic synovectomy may carry lower morbidity rates but higher recurrence rates than open synovectomy. Here, our objective was to evaluate recurrence rates and functional outcomes after primary arthroscopic synovectomy for PVNS of the knee. HYPOTHESIS: Primary arthroscopic synovectomy preserves knee function while producing low recurrence and complication rates. MATERIALS AND METHODS: We retrospectively included consecutive patients with histologically documented PVNS managed with primary arthroscopic synovectomy at two centres between 1998 and 2011. Twenty-three patients, 13 men and 10 women with a mean age of 41 ± 12 years, were reviewed including 16 patients with nodular and 7 with diffuse form of this disease. Patients with localized disease underwent partial synovectomy and those with diffuse disease complete synovectomy followed by chemical synovectomy of any residual lesions. The primary outcome measure was recurrence. Secondary outcome measures were the Tegner-Lysholm and Ogilvie-Harris scores. RESULTS: Follow-up data were obtained after a mean of 7 ± 4 years in 21 patients (14 with nodular and 7 with diffuse disease), of whom 2 had recurrences, after 2 and 5 years, respectively. At last follow-up, neither patient had any evidence of recurrence. The mean Tegner-Lysholm score was significantly improved (from 68 ± 10 to 90 ± 8, P=0.0004) and the mean Ogilvie-Harris score indicated excellent function (11 ± 1). DISCUSSION: Primary arthroscopic synovectomy ensures satisfactory control of PVNS while preserving knee function. A full recovery remains possible even in patients with diffuse disease. In the event of a recurrence, open synovectomy can be performed.

Children ankle valgus deformity treatment using a transphyseal medial malleolar screw.

INTRODUCTION: Ankle valgus deformity is rare in children. It generally leads to difficulties wearing shoes, walking instability and mechanical pain. No medical treatment is effective and the only option is surgical correction of the deformity. Two main options are available: supramalleolar osteotomy and medial malleolar epiphysiodesis. We report our experience with epiphysiodesis using a transphyseal medial malleolar screw. PATIENTS AND METHODS: This is a retrospective study of all children followed for ankle valgus and treated by transphyseal medial malleolar screw epiphysiodesis in our department. The study included 10 cases of ankle valgus deformity in seven children (four with multiple extostoses, two type 1 neurofibromatosis, one Larsen's syndrome) who completed skeletal maturity. At surgery, median bone age was 12 years (10 to 13 years and 6 months) and the median tibiotalar angle was 17.5° (10° to 30°). RESULTS: At skeletal maturity, preoperative valgus was corrected in six patients (9/10 ankles). The median tibiotalar angle was 5° (0° to 25°). Valgus was not corrected in one patient (30° to 25°). No postoperative complications occurred. DISCUSSION: Epiphysiodesis by transphyseal medial malleolar screw is a simple, efficient and safe procedure to correct a significant or symptomatic ankle valgus deformity in children before skeletal maturity. LEVEL OF EVIDENCE: Level IV, retrospective study.

Distally-based vastus lateralis muscle flap: a salvage alternative to address complex soft tissue defects around the knee.

Repeated soft tissue injuries around the knee represent challenging clinical situations where functional prognosis of the joint is often poor, especially in the presence of total knee arthroplasty (TKA). When gastrocnemius muscle flap techniques have already been used and failed, therapeutic solutions become rare. The authors suggest a regional solution to salvage these cases by the transfer of distally-based vastus lateralis muscle flaps. Four clinical operations of this muscle flap transfer are described, with three around TKA revision and one case of a post-traumatic knee amputation resulting from a compound open knee injury. Technical details of the intervention are presented. In all cases, skin closure was achieved, even if distal marginal necrosis was seen in two cases related to the type of muscle flap vascularisation.Final joint mobility was always poor (45 grades on average). Distally-based vastus lateralis muscle flaps represent a salvage procedure to correct iterative soft tissue defects around the knee that threaten short-term joint function. These muscle flaps do not require microsurgical anastomosis.