Minimally invasive periacetabular osteotomy using a modified Smith-Petersen approach: technique and early outcomes.

AIMS: Periacetabular osteotomy is an effective way of treating symptomatic hip dysplasia. We describe a new minimally invasive technique using a modification of the Smith-Peterson approach. We performed a prospective, longitudinal cohort study to assess for any compromise in acetabular correction when using this approach, and to see if the procedure would have a higher complication rate than that quoted in the literature for other approaches. We also assessed for any improvement in functional outcome. PATIENTS AND METHODS: From 168 consecutive patients (189 hips) who underwent acetabular correction between March 2010 and March 2013 we excluded those who had undergone previous pelvic surgery for DDH and those being treated for acetabular retroversion. The remaining 151 patients (15 men, 136 women) (166 hips) had a mean age of 32 years (15 to 56) and the mean duration of follow-up was 2.8 years (1.2 to 4.5). In all 90% of cases were Tönnis grade 0 or 1. Functional outcomes were assessed using the Non Arthritic Hip Score (NAHS), University of California, Los Angeles (UCLA) and Tegner activity scores. RESULTS: The mean pre-operative lateral centre-edge angle was 14.2° (-5° to 30°) and the mean acetabular index was 18.4° (4° to 40°). Post-operatively these were 31° (18° to 46°) and 3° (-7° to 29°), respectively, a significant improvement in both (p < 0.001). Allogenic blood transfusion was required in two patients (1.2%). There were no major nerve or vascular complications, and no wound infections. At the time of last follow-up, we noted a significant improvement in functional outcome scores: UCLA improved by 2.31 points, Tegner improved by 1.08 points, and the NAHS improved by 25.4 points (p < 0.001 for each). Hypermobility and longer duration of surgery were significant negative predictors for a good post-operative UCLA score, while residual retroversion was a positive predictor of post-operative UCLA score. CONCLUSION: We have found this approach to be safe and effective, facilitating early recovery from surgery. Cite this article: Bone Joint J 2017;99-B:22-8.

Probing the spiral magnetic phase in 6 nm textured erbium using polarised neutron reflectometry.

We characterise the magnetic state of highly-textured, sputter deposited erbium for a film of thickness 6 nm. Using polarised neutron reflectometry it is found that the film has a high degree of magnetic disorder, and we present some evidence that the film's local magnetic state is consistent with bulk-like spiral magnetism. This, combined with complementary characterisation techniques, show that thin film erbium is a strong candidate material for incorporation into device structures.

Magnetic Phases of Sputter Deposited Thin-Film Erbium.

We present a detailed structural and magnetic characterization of sputter deposited thin film erbium, determined by x-ray diffraction, transport measurements, magnetometry and neutron diffraction. This provides information on the onset and change of the magnetic state as a function of temperature and applied magnetic field. Many of the features of bulk material are reproduced. Also of interest is the identification of a conical magnetic state which repeats with a wavevector parallel to the c axis τc = 4/17 in units of the reciprocal lattice parameter c*, which is a state not observed in any other thin film or bulk measurements. The data from the various techniques are combined to construct magnetic field, temperature (H, T)-phase diagrams for the 200 nm-thick Er sample that serves as a foundation for future exploitation of this complex magnetic thin film system.

The incidence of stress fracture following peri-acetabular osteotomy: an under-reported complication.

Stress fractures occurring in the pubis and ischium after peri-acetabular osteotomy (PAO) are not well recognised, with a reported incidence of 2% to 3%. The purpose of this study was to analyse the incidence of stress fracture after Bernese PAO under the care of two high-volume surgeons. The study included 359 patients (48 men, 311 women) operated on at a mean age of 31.1 years (15 to 56), with a mean follow-up of 26 months (6 to 64). Complete follow-up radiographs were available for 348 patients, 64 of whom (18.4%) developed a stress fracture of the inferior pubic ramus, which was noted at a mean of 9.1 weeks (5 to 55) after surgery. Most (58; 91%) healed. In 40 of the patients with a stress fracture (62.5%), pubic nonunion also occurred. Those with a stress fracture were significantly older (mean 33.9 years (16 to 50) vs 30.5 years (15 to 56), p = 0.002) and had significantly more mean pre-operative deformity: mean centre-edge angle (9.8° (-9.5 to 35) vs 12.4° (-33 to 28), p = 0.04) and mean Tönnis angle (22.8° (0 to 45) vs 18.7° (-2 to 38), p < 0.001). The pubic nonunion rate was significantly higher in those with a stress fracture (62.5% vs 7%, p < 0.001), with regression analysis revealing that these patients had 11.8 times higher risk than those without nonunion.

The results of uncemented total hip replacement in children with juvenile idiopathic arthritis at ten years.

The inherent challenges of total hip replacement (THR) in children include the choice of implant for the often atypical anatomical morphology, its fixation to an immature growing skeleton and the bearing surface employed to achieve a successful long-term result. We report the medium-term results of 52 consecutive uncemented THRs undertaken in 35 paediatric patients with juvenile idiopathic arthritis. The mean age at the time of surgery was 14.4 years (10 to 16). The median follow-up was 10.5 years (6 to 15). During the study period 13 THRs underwent revision surgery. With revision as an endpoint, subgroup analysis revealed 100% survival of the 23 ceramic-on-ceramic THRs and 55% (16 of 29) of the metal- or ceramic-on-polyethylene. This resulted in 94% (95% CI 77.8 to 98.4) survivorship of the femoral component and 62% (95% CI 41.0 to 78.0) of the acetabular component. Revision of the acetabular component for wear and osteolysis were the most common reasons for failure accounting for 11 of the 13 revisions. The success seen in patients with a ceramic-on-ceramic articulation seems to indicate that this implant strategy has the potential to make a major difference to the long-term outcome in this difficult group of patients.

Strain dependent selection of spin-slip phases in sputter deposited thin-film epitaxial holmium.

We report the structural and magnetic characterization of sputter deposited epitaxial Ho. We present room temperature characterization by atomic force microscopy and x-ray diffraction and temperature dependent characterization by x-ray diffraction and neutron diffraction. The data show the onset and change of the magnetic state as a function of temperature. Films of different thickness, exhibiting signs of differing epitaxially induced strain, tend towards specific spin-slip phases in the low temperature regime. The more highly strained thinnest films tend towards values with a longer magnetic wavelength.

Early to mid-term results of ceramic-on-ceramic total hip replacement: analysis of bearing-surface-related complications.

Ceramic-on-ceramic bearings in hip replacement have low rates of wear and are increasingly being used in young adults. Our aim was to determine the incidence of audible phenomena or other bearing-related complications. We retrospectively analysed 250 ceramic-on-ceramic hip replacements in 224 patients which had been implanted between April 2000 and December 2007. The mean age of the patients at operation was 44 years (14 to 83) and all the operations were performed using the same surgical technique at a single centre. At a mean follow-up of 59 months (24 to 94), the mean Oxford hip score was 40.89 (11 to 48). There were six revisions, three of which were for impingement-related complications. No patient reported squeaking, but six described grinding or clicking, which was usually associated with deep flexion. No radiological evidence of osteolysis or migration of the components was observed in any hip. The early to mid-term results of contemporary ceramic-on-ceramic hip replacement show promising results with few concerns in terms of noise and squeaking. Positioning of the acetabular component remains critical in regard to the reduction of other impingement-related complications.

Controlled injection of spin-triplet supercurrents into a strong ferromagnet.

The superconductor-ferromagnet proximity effect describes the fast decay of a spin-singlet supercurrent originating from the superconductor upon entering the neighboring ferromagnet. After placing a conical magnet (holmium) at the interface between the two, we detected a long-ranged supercurrent in the ferromagnetic layer. The long-range effect required particular thicknesses of the spiral magnetically ordered holmium, consistent with spin-triplet proximity theory. This enabled control of the electron pairing symmetry by tuning the degree of magnetic inhomogeneity through the thicknesses of the holmium injectors.

Structural and functional analysis of nanopillar spin electronic devices fabricated by 3D focused ion beam lithography.

We discuss the fabrication of nanopillar spin electronic devices from metal multilayered heterostructures, utilizing a novel three-dimensional focused ion beam lithography process. Finite element simulation was performed to optimize the geometry of the nanopillar device and to demonstrate that current flow is perpendicular to the plane within the active region of the device. Clear zero-field current induced magnetization switching is observed in our nanopillar devices at room temperature.

Intense hypoxic cycle exercise does not alter lung density in competitive male cyclists.

We tested the hypothesis that intense short duration hypoxic exercise would result in an increase in extravascular lung water (EVLW), as evidenced by an increase in lung density. Using computed tomography (CT), baseline lung density was obtained in eight highly trained male cyclists (mean +/- SD: age = 28 +/- 8 years; height = 180 +/- 9 cm; mass = 71.6 +/- 8.2 kg; VO2max= 65.0 +/- 5.2 ml kg min(-1)). Subjects then completed an intense hypoxic exercise challenge on a cycle ergometer and metabolic data, HR and %S(p)O2 were recorded throughout. While breathing 15% O2, subjects performed five 3 km cycling intervals (mean power, 286 +/- 20 W; HR = 91 +/- 4% HRmax) separated by 5 min of recovery. From a resting hypoxic S(p)O2 of 92 +/- 4%, subjects further desaturated during exercise to 76 +/- 3%. CT scans were repeated 76 +/- 10 min (range 63-88 min) following the completion of exercise. There was no change in lung density from pre (0.18 +/- 0.02 g ml(-1)) to post-exercise (0.18 +/- 0.04 g ml(-1)). The substantial reduction in S(p)O2 may be explained by a number of potential mechanisms, including decreased pulmonary diffusion capacity, alveolar hypoventilation, reduced red cell transit time, ventilation/perfusion inequality or a temperature and pH induced rightward-shift in the oxyhaemoglobin dissociation curve. Alternatively, the integrity of the blood gas barrier may have been disrupted without any measurable increase in lung density.

Triplate fixation: a new technique in limb-salvage surgery.

Massive endoprostheses using a cemented intramedullary stem are widely used to allow early resumption of activity after surgery for tumours. The survival of the prosthesis varies with the anatomical site, the type of prosthesis and the mode of fixation. Revision surgery is required in many cases because of aseptic loosening. Insertion of a second cemented endoprosthesis may be difficult because of the poor quality of the remaining bone, and loosening recurs quickly. We describe a series of 14 patients with triplate fixation in difficult revision or joint-sparing tumour surgery with a minimum follow-up of four years. The triplate design incorporated well within a remodelled cortex to achieve osseomechanical integration with all patients regaining their original level of function within five months. Our preliminary results suggest that this technique may provide an easy, biomechanically friendly alternative to insertion of a further device with an intramedullary stem, which has a shorter lifespan in revision or joint-sparing tumour surgery. A short segment of bone remaining after resection of a tumour will not accept an intramedullary stem, but may be soundly fixed using this method.

Isolated inflammatory coxitis associated with protrusio acetabuli: a new form of juvenile idiopathic arthritis?

BACKGROUND: Isolated hip disease in the context of chronic childhood inflammatory arthritis is uncommon. This paper reports 14 children who presented to the rheumatology and orthopaedic departments of our hospitals with severe hip symptoms, and who continued to have primarily hip disease throughout their clinical course. Our aim was to characterize and present the relevant demographic, clinical, investigational, treatment and outcome data from the above cohort. METHODS: All paediatric cases with the diagnosis of protrusio acetabuli, Otto pelvis or idiopathic chondrolysis who were seen in the past 15 yr at Great Ormond Hospital and Middlesex Hospital in London were identified and their case notes were searched retrospectively for relevant information. RESULTS: In 11 cases, the disease progressed to involve no joints other than the contralateral hip. None were considered to have a specific subtype of juvenile idiopathic arthritis (JIA) and all tested were negative for HLA-B27. Elevation of serum inflammatory markers was variable. Protrusio acetabuli was the predominant radiological feature. There were definite inflammatory changes on the gadolinium-enhanced magnetic resonance imaging study in all patients who had this procedure performed (seven cases). Microbiological investigations were all consistently negative. Severe hip disease resulted in considerable ongoing symptoms and disability. Six cases were treated with disease-modifying anti-rheumatic drugs. Total hip replacement has been required in four patients to date, with major functional improvement. CONCLUSIONS: These cases represent severe and disabling primary hip disease with considerable clinical and investigational inflammatory features. Such a mode of presentation has not been described previously in the context of childhood chronic inflammatory arthritides, and may represent a separate oligoarthritis subtype of JIA.

Dispersal of the Ponto-Caspian amphipod Echinogammarus ischnus: invasion waves from the Pleistocene to the present.

The geographical range of the amphipod crustacean Echinogammarus ischnus has expanded over the past century from the Ponto-Caspian region to Western Europe, the Baltic Sea, and the Great Lakes of North America. The present study explores the phylogeographic patterns of this amphipod across its current distribution, based on an examination of nucleotide diversity in the mitochondrial cytochrome c oxidase subunit I (COI) gene. Marked genetic divergence exists among populations of E. ischnus from the Black and Caspian Seas, as well as those from the drainage system of the Black Sea. This divergence suggests the prolonged geographic isolation of these native populations, reflecting the limited dispersal capability of E. ischnus. By contrast, invading populations are characterized by a lack of genetic variation; a single mitochondrial genotype of Black Sea origin has colonized sites from the Rhine River to North America. The dispersal pattern in E. ischnus is very similar to that in the Ponto-Caspian cladoceran Cercopagis pengoi. Despite their contrasting life history strategies, these invading species followed the same route of invasion from the northern Black Sea to the Baltic Sea region, and subsequently to North America.

Analysis of the referral pattern to a supraregional bone and soft tissue tumour service.

AIM: To investigate the sources of delay in diagnosis and determine if there was a similar diagnostic error rate as found by the Musculoskeletal Tumour Society, which subsequently altered patients' management and affected outcome. PATIENTS AND METHODS: A prospective review of 100 consecutive patients referred to our institution analysed causes for delay in referral and whether prior investigations or procedures had complicated further management. RESULTS: Patients were symptomatic for 14.8 months (range, 0-26 months) prior to consultation with their GP. A further 13.5 months (range, 0.5-120 months) elapsed before referral by the local hospital (94) or GP (6) to the bone and soft tissue service. A significant delay in referral of more than a month occurred in 72 patients. Those patients with malignant disease were symptomatic for 7.6 months (range, 0.5-11 months) prior to seeking medical advice with a further 7.5 months (range, 0-13 months) elapsing prior to onward referral at their local hospital. From the study group, 63 patients were subjected to complex imaging studies (bone scan, CT, MRI) prior to referral; 34 biopsies or surgery were performed in 34 cases by referring teams, 16 of which complicated subsequent management. CONCLUSIONS: If a high suspicion of a soft tissue or bone tumour is suspected from the history, examination and plain radiograph, then early referral to a specialist centre is recommended where relevant, high-quality investigations can be arranged in a short time leading to a planned biopsy, confirmation of diagnosis and definitive treatment at an earlier stage.

Usefulness of the Framingham risk score and body mass index to predict early coronary artery calcium in young adults (Muscatine Study).

The value of a coronary artery disease prediction algorithm, the Framingham risk score (score), for detecting coronary artery calcium (CAC) was examined in 385 men and 472 women, aged 29 to 43 years. Scores were compared in subjects with and without CAC and were also used to predict presence of CAC. Receiver-operating characteristic curves were computed to compare different prediction models. The score model was compared with age only, natural logarithm of body mass index (lnBMI) only, and score plus lnBMI models. CAC was detected in 30% of men and 16% of women. The mean score was significantly higher in men and women with CAC. For every 2-point increase in the score, the odds of CAC increased by 30% in women and 20% in men. Significant associations between CAC status and risk factors were observed for age in women, and high- density lipoprotein cholesterol and blood pressure in men and women. The area under the receiver-operating characteristic curve for the score was 0.67 and 0.57 for women and men, respectively. When lnBMI was added to the score model, the area increased to 0.76 in women (lnBMI p <0.0001, score p <0.005). For men, the area increased from 0.57 to 0.67, and the score was no longer significant (p >0.60) in the model with lnBMI (p <0.0001). Score predicts CAC in asymptomatic young adults. Inclusion of lnBMI in the score model adds significantly to the prediction of CAC in women and men. The lnBMI model has a greater predictive value than the score in this young population.

Fibrous hamartoma of infancy at the wrist and the use of MRI in preoperative planning.

Fibrous hamartoma of infancy is an uncommon, self-limiting benign tumour that presents during the first 2 years of life, developing from subcutaneous fibrous tissue proliferation at almost any site. We describe the results of MRI of a lesion at the wrist. The scans enabled a planned surgical resection with the aim of preventing local recurrence without damaging important neurovascular structures.

Interstitial laser photocoagulation for the treatment of osteoid osteoma.

We report the results of a prospective study of 23 patients in which interstitial laser photocoagulation (ILP) was used to treat an osteoid osteoma. ILP is a technique in which tumour tissue is destroyed by direct heating using low-power laser light energy delivered by thin (400 microm) optical fibres which are introduced percutaneously into the tumour under image guidance. Pain was evaluated before operation and at the latest follow-up using a visual analogue scale with 0 denoting no pain and 10 the worst pain imaginable. The mean follow-up was for 15 months. The results showed that the mean pain score decreased from 7.5 before operation to 0.95 at the latest follow-up. Fourteen patients had no pain and eight had minor discomfort, not requiring analgesia. One patient required a second procedure because placement of the fibre had not been accurate enough and one developed recurrent symptoms eight months after treatment. All patients were satisfied with the operation because of the rapid resolution of pain, the minimally invasive nature of the procedure, and the fact that there was no postoperative restriction of activity.

Identification of glycosomes and metabolic end products in pathogenic and nonpathogenic strains of Cryptobia salmositica (Kinetoplastida: Bodonidae).

Whole cell lysates of pathogenic and nonpathogenic strains of Cryptobia salmositica were subjected to subcellular fractionation using differential and isopycnic centrifugation in sucrose. The glycolytic enzymes hexokinase, fructose-1,6-biphosphate aldolase, triosephosphate isomerase, glucosephosphate isomerase and glyceraldehyde-3-phosphate-dehydrogenase and the peroxisomal enzyme catalase were associated with a microbody that had a buoyant density in sucrose of 1.21 g cm-3. Lactate dehydrogenase was detected in whole cell lysates, but not in purified organelles. A microbody with a positive reaction for catalase was detected in electron microscope sections of the pathogenic and nonpathogenic strains. These catalase-containing microbodies fused with lipid bodies and vacuoles, arose by division from pre-existing microbodies and expelled their contents into the cytoplasm of the cell. Both strains also modified the catalase content in their microbodies. Under aerobic conditions, they metabolized glucose to pyruvate and lactate. We conclude that part of the glycolytic pathway in C. salmositica is compartmentalized in a microbody called the glycosome.