Speedy light focusing through scattering media by a cooperatively FPGA-parameterized genetic algorithm

We developed an accelerated Genetic Algorithm (GA) system based on the cooperation of a field-programmable gate array (FPGA) and the optimized parameters that enables fast light focusing through scattering media. Starting at the searching space, which influences the convergence of the optimization algorithms, we manipulated the mutation rate that defines the number of mutated pixels on the spatial light modulator to accelerate the GA process. We found that the enhanced decay ratio of the mutation rate leads to a much faster convergence of the GA. A convergence-efficiency function was defined to gauge the tradeoff between the processing time and the enhancement of the focal spot. This function allowed us to adopt the shorter iteration number of the GA that still achieves applicable light focusing. Furthermore, the accelerated GA configuration was programmed in FPGA to boost processing speed at the hardware level. It shows the ability to focus light through scattering media within a few seconds, 150 times faster than the PC-based GA. The processing cycle could be further promoted to a millisecond-level with the advanced FPGA processor chips. This study makes the evolution-based optimization approach adaptable in dynamic scattering media, showing the capability to tackle wavefront shaping in biological material.

Humoral and cellular immune response to tick-borne-encephalitis (TBE) vaccination depends on booster doses in patients with Juvenile Idiopathic Arthritis (JIA)

Juvenile Idiopathic Arthritis (JIA) patients living in areas with high prevalence of tick-borne-encephalitis-virus-(TBEV)-infection are recommended for administration of inactivated TBE-vaccination. However, there are serious concerns regarding protective vaccine-induced immune responses against TBEV in immunocompromised patients. The present study aimed to analyze the humoral and cellular immune response to TBE-vaccination in previously TBE-vaccinated JIA patients compared to healthy controls (HC) including investigation of IgG-anti-TBEV avidity, neutralization capacity, cellular reactivity by IFNgamma-ELISPOT and cytokine secretion assays. Similar IgG-anti-TBEV antibody concentrations, neutralization titers and cellular reactivity were found between JIA and HC. The number and the early timing of booster vaccinations after primary vaccination had the most prominent effect on neutralizing antibodies in JIA and on IgG-anti-TBEV concentrations in both JIA and HC. Administration of booster vaccinations made it more likely for JIA patients to have IgG-anti-TBEV concentrations ≥165 VIEU/ml and avidities >60%. TNF-alpha inhibitors had a positive and MTX administration a negative effect on humoral immune responses. In conclusion, irrespective of having JIA or not, vaccinated children showed similar humoral and cellular immunity against TBEV several years after primary TBE-vaccination. However, in JIA, booster vaccinations mounted a significantly higher humoral immune response than in JIA without boosters. Our results highlight the need for timely administration of boosters particularly in JIA. Although immunosuppressive treatment at vaccinations in diagnosed JIA had a negative effect mainly on TBEV-specific cellular immunity, most JIA patients mounted a favorable humoral immune response which was maintained over time. Thus, successful TBE-vaccination seems highly feasible in JIA patients with immunosuppressive regimens.

Computer-assisted surgery and navigation in foot and ankle: state of the art and fields of application

Computer-assisted orthopaedic surgery (CAOS) is a real-time navigation guidance system that supports surgeons intraoperatively.Its use is reported to increase precision and facilitate less-invasive surgery.Advanced intraoperative imaging helps confirm that the initial aim of surgery has been achieved and allows for immediate adjustment when required.The complex anatomy of the foot and ankle, and the associated wide range of challenging procedures should benefit from the use of CAOS; however, reports on the topic are scarce.This article explores the fields of applications of real-time navigation and CAOS in foot and ankle surgery. Cite this article: EFORT Open Rev 2021;6:531-538. DOI: 10.1302/2058-5241.6.200024.

Impact du confinement sur le suivi des immunothérapies orales alimentaires : étude multicentrique dans 3 centres d’Île-de-France

But de l’étude

Plusieurs études ont confirmé l’impact du confinement sur la population, entraînant une rupture de soins, des effets somatiques et psychologiques. Notre étude s’intéresse aux effets indésirables et aux problèmes d’observance au cours d’immunothérapie orale (ITO) alimentaires pendant le confinement.

Patients et méthodes

Au total, 132 patients, majoritairement des enfants (95 %), avec un antécédent atopique (60 %) suivis pour une ITO ont été inclus dans 3 centres d’allergologie en Île-de-France, pendant le confinement lié à la pandémie SARS-Cov-2 du 16/03 au 11/05/20. Les aliments des ITO étaient principalement l’arachide (38 %), le lait de vache (24 %), la noisette (14 %), l’œuf (9 %), la noix de cajou et la pistache (8 %).

Résultats

Des effets indésirables ont été retrouvés chez 13 patients soit 10 % des cas. Ces réactions étaient principalement de grade 1 et 2 selon la classification de Ring et Messmer. Trois patients ont présenté des réactions de grade 3 et six patients ont utilisé l’adrénaline au domicile. L’observance était correcte dans 81 % des cas sans aucun oubli. Trois patients ont augmenté leur dose quotidienne sans avis médical. Nous n’avons pas retrouvé de différence significative dans l’analyse en sous-groupe comparant des enfants appariés en âge suivis en ITO en 2019 et en 2020 sur la même période dans le même hôpital.

Conclusion

Il n’y a pas eu d’augmentation des effets indésirables au cours d’ITO pendant la période du confinement. L’éducation thérapeutique au cours de l’ITO est primordiale et participe à réduire la survenue d’effets indésirables.

Quantification of hyaluronan in human fasciae: variations with function and anatomical site

Recently, alterations in fascial gliding-like movement have been invoked as critical in the etiology of myofascial pain. Various methods have been attempted for the relief of this major and debilitating clinical problem. Paramount have been attempts to restore correct gliding between fascial layers and the movement over bone, joint, and muscular structures. One of the key elements that underlies such fascial movement is hyaluronan. However, until now, the precise content of hyaluronan within fasciae has been unknown. This study quantifies for the first time the hyaluronan content of human fascial samples obtained from a variety of anatomic sites. Here, we demonstrate that the average amount varies according to anatomic site, and according to the different kinds of sliding properties of the particular fascia. For example, the fascia lata has 35 μg of hyaluronan per gram of tissue, similar to that of the rectus sheath (29 μg g^-1 ). However, the types of fascia adherent to muscle contain far less hyaluronan: 6 μg g^-1 in the fascia overlying the trapezius and deltoid muscles. In the fascia that surrounds joints, the hyaluronan increases to 90 μg g^-1 , such as in the retinacula of the ankle, where greater degrees of movement occur. Surprisingly, no significant differences were detected at any site as a function of age or sex (P-value > 0.05, t-test) with the sole exception of the plantar fascia. This work can provide a better understanding of the role of hyaluronan in fascia. It will facilitate a better comprehension of the modulation of the hyaluronan-rich layer that occurs in relation to the various conditions that affect fascia, and the diverse factors that underlie the attendant pathologies.

On the in Vivo Clearance of Thrombin

The turnover of labeled bovine thrombin was studied in heparinized dogs. The results of these studies indicate that

1. thrombin is rapidly removed from the blood, clearance takes place predominantly by the liver ;

2. the uptake occurs by the Kupffer cells ;

3. after its uptake the thrombin is rapidly broken down ;

4. in the absence of the liver thrombin is slowly cleared by extrahepatic phagocytes ;

5. the rate of thrombin clearance is so rapid and its critical dose so small that this protein can be used to study hepatic blood flow and Kupffer cell clearance function.

Additional muscular slip of the flexor digitorum longus muscle to the fifth toe

Despite the fact that there are numerous reports on muscular variations in the sole of the foot, routine dissection in a formaldehyde-fixed cadaver revealed an accessory flexor digiti quinti muscle, which to the best of our knowledge is a very unusual variant. This was in the form of a slender, 38 mm long muscular slip, with a proximal and distal tendon extending from the common flexor digitorum longus tendinous plate out to the distal phalanx of the fifth toe. An associated finding was the absence of the musculotendinous portion of the flexor digitorum brevis to the same toe. A developmental explanation for this variation is presented. Clinical implications with regard to this anatomical condition may result in clawing of the fifth toe.

Repair of syndesmosis injury in ankle fractures: Current state of the art

Conventional treatment of syndesmosis injuries in rotationally unstable ankle fractures is associated with an unacceptably high rate of malreduction, and this has led to a paradigm shift in the approach to a newer concept of anatomical repair.

In the anatomical approach, the principle is to ‘directly fix what is broken and repair what is torn’. The approach is effective in reducing the rate of syndesmosis malreduction, increasing the biomechanical strength of syndesmosis fixation and avoiding the need for trans-syndesmotic fixation and its secondary removal.

The objective of this review article is to compare the conventional treatment of these injuries (accepted usage, general consent, traditional, generally accepted) with a newer anatomical approach to be considered as a shift in thinking.

Cite this article: EFORT Open Rev 2018;3:24-29. DOI: 10.1302/2058-5241.3.170017

Why do patients occupy acute psychiatry beds? A pilot study

The main aim of this pilot study was to identify factors influencing acute psychiatry bed use. The reasons for occupying a bed vary with time, so patients in the study were assessed on a weekly basis to monitor the changes in the factors thought to be responsible for continued stay. The reasons for bed occupancy also are often only known to those professionals directly involved in day to day care of patients, and it is suspected that the reasons often have little to do with manifest psychiatric illness. The reason for this study was to investigate this question.

Commentary

Warwick's paper shows how recent advances have completely altered the previous therapeutic nihilism expressed in the above quotation. Physicians and surgeons have long been aware that medical and surgical problems turn out to have no organic cause. Joyce et al (1986) from New Zealand examined 105 people with abdominal pain who had been admitted to a surgical ward. They found that the most common surgical diagnosis was non-specific abdominal pain, closely followed by appendicitis. Those with non-specific abdominal pain contained a very interesting group of patients: they were predominantly female, did not have any physical findings, and were more anxious and conformed to the pattern of patients showing fear of illness. This group presented, in the words of the New Zealand team:

Behavioural-cognitive psychotherapy training for psychiatrists

“The therapist can cite Bertrand Russell's observation that the degree of certainty with which one holds a belief is inversely related to the truth of that belief. Fanatics are true believers, scientists are sceptics”. (Beck et al, 1979)

I propose to describe the evolution of behavioural treatments, and the more recent leap forward made by cognitive therapy. Exciting new treatments are now available that did not exist when I was a trainee. The accepted term for these treatments is “behavioural-cognitive psychotherapy’ (BCPT). They are behavioural in the sense that emphasis is on observable behaviour, e.g. avoidance of supermarkets in agoraphobia. They are cognitive because many approaches involve working with patients' thoughts, e.g. the negative thinking of depressed patients. The treatment is psychotherapy as it is therapy that works at the mind level, rather than at say the synaptic level as pharmacotherapy does. BCPT combines well with pharmacotherapy, and other therapeutic methods such as social therapy, and so is suitable for a multidisciplinary approach to a psychiatric problem, as well as offering specific techniques for identified disorders.

Comparison of the Otto Bock solid ankle cushion heel foot with wooden keel to the low-cost CR-Equipements™ solid ankle cushion heel foot with polypropylene keel: A randomized prospective double-blind crossover study assessing patient satisfaction and energy expenditure

BACKGROUND

The International Committee of the Red Cross supports a worldwide program of prosthetic fitting and rehabilitation. In this context, a prosthetic foot was developed and widely distributed in least developed countries.

STUDY DESIGN

Prospective, randomized, double-blind, controlled study.

OBJECTIVE

To compare patient satisfaction and energy expenditure during ambulation between a low-cost prosthetic foot designed with a polypropylene keel (CR-Equipements^™ solid ankle cushion heel, International Committee of the Red Cross) to a well-recognized solid ankle cushion heel foot with a wooden keel (solid ankle cushion heel foot, Otto Bock).

METHODS

A total of 15 participants with unilateral transtibial amputation were evaluated using the two prosthetic feet in a randomized prospective double-blind crossover study. Main outcomes were patient satisfaction questionnaires (Satisfaction with Prosthesis Questionnaire and prosthetic foot satisfaction) and energy expenditure (oxygen consumption-mL/kg/min, oxygen cost-mL/kg/m, and heart rate-bpm).

RESULTS

There were no significant differences between the two prosthetic feet for satisfaction and energy expenditure.

CONCLUSION

The low-cost solid ankle cushion heel foot with polypropylene keel provides comparable satisfaction and similar energy expenditure as the solid ankle cushion heel foot with wooden keel. Clinical relevance The results of this study support the application and widespread use of the CR-Equipements^™ solid ankle cushion heel foot. From a cost-effectiveness standpoint, patients are well satisfied and exhibit similar outcomes at a substantially lower cost.

Hawkins' type-II talar fracture with subtalar dislocation: A very unusual combination

We report the unusual case of a 16-year-old young man who sustained a rare association of a Hawkins' type-II talar neck fracture with a complete medial subtalar dislocation (Hawkins type-IIB) that occurred as an isolated injury after indirect trauma during a soccer game. Following closed reduction of the subtalar dislocation, standard radiographs and computed tomography (CT) demonstrated a comminuted fracture of the talus involving the base of the talar neck. Open reduction was performed and the fracture was stabilized by ORIF. At 1-year follow-up, functional and radiographic outcomes were graded as excellent, with no radiographic evidence of talar osteonecrosis.

Technique tip: Simultaneous first metatarsal lengthening and metatarsophalangeal joint fusion for failed hallux valgus surgery with transfer metatarsalgia

BACKGROUND

Failed hallux valgus surgery may result in residual or recurrent hallux valgus, and as well transfer metatarsalgia. The present technical tip concerns the combination of fusion of the first metatarsophalangeal (MTP) joint and lengthening of the first metatarsal (MT) through a scarf osteotomy.

MATERIALS AND METHODS

Six patients underwent the presented technique, all for the indication of failed hallux valgus surgery with shortening of the first MT and degenerative changes in the 1st MTP joint.

RESULTS

Follow-up at six months revealed all patients had complete healing of the osteotomy and arthrodesis sites. They were all asymptomatic and fully active, completely satisfied with the outcome.

CONCLUSIONS

Combined fusion of the first MTP joint and lengthening of the first MT through a scarf osteotomy results in an excellent outcome in patients with failed hallux valgus surgery with shortening of the first MT and degenerative changes in the 1st MTP joint.

Syndesmosis reduction by computer-assisted orthopaedic surgery with navigation: Feasibility and accuracy in a cadaveric study

INTRODUCTION

Syndesmotic disruption may be difficult to reduce and fix, and malreduction is associated with inferior outcomes. Intraoperative computed tomography (CT) can provide accurate assessment of syndesmotic reduction. We hypothesized that three-dimensional (3-D) computer-assisted orthopaedic surgery (CAOS) with navigation of syndesmotic reduction could avoid malreduction. Our goal was to assess feasibility and accuracy of such a technic in a cadaveric study.

METHOD

Eleven through-the-knee cadaveric specimens were used. Ankle CT as control was obtained prior to intervention. The syndesmosis was destabilized by sectioning the tibiofibular ligaments, producing a malreduction temporarily fixed with a Kirschner wire (K-wire). With reference base fixed to the tibia an acquisition scan was made. A K-wire was fixed to the fibula. The K-wire holding the syndesmosis malreduced was removed. The fibula was reduced within the syndesmosis under 3-D CAOS using a navigated K-wire. Once optimal position was obtained by referencing control images, the syndesmosis was fixed with a 3.5mm screw. A CT scan was performed to assess quality of reduction.

RESULTS

Position of the fibula in control and post-reduction CT scans showed a mean anterior-posterior displacement of 0.74 (±0.62)mm. The medial-lateral position measured a mean displacement of 0.68 (±0.76)mm. Rotation of the fibula revealed a mean difference of 0.99° (± 0.73).

CONCLUSION

In this cadaveric study, CAOS with navigation allowed for very accurate syndesmosis reduction. This appears to be a promising technique to be confirmed by clinical study.

Field-stepped broadband NMR in pulsed magnets and application to SrCu2(BO3)2 at 54T

Pulsed magnets generate the highest magnetic fields as brief transients during which the observation of NMR is difficult, however, this is the only route to unique insight into material properties up to the regime of 100T. Here, it is shown how rather broad NMR spectra can be assembled in a pulsed magnet during a single field pulse by using the inherent time dependence of the field for the recording of field-stepped free induction decays that cover a broad frequency range. The technique is then applied to (11)B NMR of the spin-dimer system SrCu2(BO3)2, a magnetic insulator known to undergo a series of field-driven changes of the magnetic ground state. At peak fields of about 54T at the Dresden High Magnetic Field Laboratory, (11)B NMR spectra spanning a total of about 9MHz width are reconstructed. The results are in good accordance with a change from a high-temperature paramagnetic state to a low-temperature commensurate superstructure of field-induced spin-dimer triplets.

Intraoperative 3-Dimensional Computed Tomography and Navigation in Foot and Ankle Surgery

Computer-assisted orthopedic surgery has developed dramatically during the past 2 decades. This article describes the use of intraoperative 3-dimensional computed tomography and navigation in foot and ankle surgery. Traditional imaging based on serial radiography or C-arm-based fluoroscopy does not provide simultaneous real-time 3-dimensional imaging, and thus leads to suboptimal visualization and guidance. Three-dimensional computed tomography allows for accurate intraoperative visualization of the position of bones and/or navigation implants. Such imaging and navigation helps to further reduce intraoperative complications, leads to improved surgical outcomes, and may become the gold standard in foot and ankle surgery. [Orthopedics.2016; 39(5):e1005-e1010.].

Clinical Outcomes and Development of Symptomatic Osteoarthritis 2 to 24 Years After Surgical Treatment of Tarsometatarsal Joint Complex Injuries

BACKGROUND

Injuries to the tarsometatarsal (TMT) joint complex, or Lisfranc injuries, have been reported to result in osteoarthritis (OA) following surgical treatment. Good outcomes with respect to short and medium-term results have been reported. However, long-term results, specifically regarding clinical outcomes and the development of symptomatic OA, are limited. The objectives of this study were to assess clinical outcomes, the occurrence of symptomatic OA, and risk factors for OA at 2 to 24 years after a Lisfranc injury treated surgically with open reduction and internal fixation (ORIF) or with primary arthrodesis.

METHODS

This was a retrospective study involving 61 patients treated surgically at our institution between 1988 and 2009 for an injury to the TMT joint complex. Patients underwent either ORIF with transarticular screws or primary arthrodesis when joint comminution at the TMT level was such that ORIF was not possible. Functional outcomes were assessed according to the American Orthopaedic Foot & Ankle Society (AOFAS) score, the Foot Function Index (FFI), and a visual analog scale (VAS) for pain. Global health was evaluated with the Short Form (SF)-12 Health Survey physical component summary (PCS).

RESULTS

Sixty-one of the 128 patients were available for clinical evaluation, including the use of questionnaires, and radiographic assessment at a mean of 10.9 years postoperatively (range, 2.4 to 23.9 years). Mean scores were as follows: AOFAS score, 79.0; FFI, 16.9, and VAS for pain, 2.5. Radiographic evidence of OA was noted in 44 (72.1%) of the patients, and symptomatic OA, in 54.1%, the latter having worse outcomes. Risk factors for OA were nonanatomic reduction, fracture classification of Myerson type C, and a history of smoking.

CONCLUSIONS

Two to 24 years following surgical treatment to restore and maintain joint anatomy for Lisfranc injuries, we found satisfactory clinical outcome scores and a large number of patients who had returned to their previous level of functioning and employment, with little need for secondary procedures. However, there was a substantial occurrence of posttraumatic OA, as evident on radiographs, albeit the occurrence of symptomatic OA was lower.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Masquelet Technique for Midfoot Reconstruction Following Osteomyelitis in Charcot Diabetic Neuropathy: A Case Report

CASE

We describe a case of ulcerative midfoot osteomyelitis in a patient with Charcot diabetic neuropathy. After debridement, an extensive osseous defect led to staged reconstruction in an attempt to salvage the foot. We describe the presentation, the treatment, and the technical points of this challenging case.

CONCLUSION

We reconstructed the midfoot defect with use of the induced-membrane Masquelet technique, successfully reestablishing a stable, well-aligned, plantigrade, ulcer-free foot.

Radiographic evaluation of posttraumatic osteoarthritis of the ankle: the Kellgren-Lawrence scale is reliable and correlates with clinical symptoms

OBJECTIVE

To assess reliability and construct validity of the Kellgren-Lawrence (K&L) scale in posttraumatic ankle osteoarthritis (OA); additionally evaluate the validity of including tibiotalar tilting in the scale.

METHOD

One-hundred and fifty ankle radiographs (75 patients, unilateral malleolar fractures) evaluated at average of 18 years after surgery. American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot (HF) score and pain (visual analog scale) were recorded. Grading of OA according to K&L criteria and identification of OA features was performed on standardized radiographs by four physicians. Minimal joint space width, sclerosis, and talar tilt angle were quantified by digital measurements. A modified K&L scale including talar tilting is presented. Validity of original and modified scale was evaluated and expressed as ability to (1) Identify those with clinical symptoms of ankle OA; and (2) Distinguish between different degrees of fracture severity.

RESULTS

Inter- and intra-observer reliability of OA assessment according to K&L were good (ICC 0.61 and 0.75). Original and modified K&L grades significantly increased with decreasing AOFAS ankle-HF scores and greater pain. A talar-tilt angle > 2° compared with ≤ 2° in grade 3 was associated with significantly higher pain levels (VAS pain 4.2 vs 1.4, respectively; mean difference 2.8, 95% CI 0.5-5.1). More severe fracture patterns at time of surgery were more often in patients with the highest K&L grades.

CONCLUSIONS

The K&L scale is a valid and reliable radiographic grading system for assessment of ankle OA. Inclusion of the talar tilt angle might allow for better differentiation with respect to clinical outcomes.

Effect of Vancomycin Therapy for Osteomyelitis on Colonization by Methicillin-ResistantStaphylococcus aureus: Lack of Emergence of Glycopeptide Resistance

Background:

In treating orthopedic infections, the long-term impact of vancomycin therapy on colonization by methicillin-resistantStaphylococcus aureus(MRSA) and the emergence of vancomycin-intermediate S.aureusis unknown.

Design:

Prospective surveillance of the effect of long-term vancomycin therapy on colonization by MRSA and the emergence of vancomycin-intermediateS. aureus.

Methods:

Thirty-four patients with MRSA osteomyelitis that was microbiologically documented were longitudinally observed for the emergence of vancomycin-intermediate S.aureusat 3 body sites (wound, anterior nares, and groin) during the initial period of vancomycin therapy and at the 2-month follow-up. Twenty patients received the standard dose (20 mg/kg/d) for 34 ± 6 days and 14 patients received a high dose (40 mg/kg/d) of vancomycin for 37 ± 9 days.

Results:

During vancomycin treatment, global MRSA carriage (all body sites) fell from 100% to 25% in the group of patients receiving the standard dose of vancomycin, and from 100% to 40% in the group receiving the high dose. During the 2-month follow-up period after vancomycin therapy, global MRSA carriage increased from 25% to 55% in the group receiving the standard dose and decreased from 43% to 36% in the group receiving the high dose.

Conclusion:

Therapy with a high dose of vancomycin contributes to the sustained eradication of MRSA carriage without promoting the emergence of glycopeptide resistance.

Absence of skin rash in Goodpasture's syndrome: the hyaluronan effect

Goodpasture's syndrome is a rare disease that involves rapidly progressive kidney failure as well as hemorrhagic lung disease. It is a form of autoimmune disorder with unusual features; marked male preponderance, in contrast with other autoimmune disease in which females are at far greater risk. The autoantibodies are directed again the carboxy-extension non-collagenous (NC1) portion of one of the basement membrane-specific collagen IV alpha 3 chains. Basal laminas throughout the body share this structure, including those in kidney, lung and skin. But curiously, skin is rarely involved in Goodpasture's syndrome. Hyaluronan is a large extracellular matrix carbohydrate polymer. Half of total body hyaluronan occurs in skin. High molecular weight hyaluronan, a potent immunosuppressive polymer, might be functioning as an immune shield for skin in Goodpasture's syndrome, and be the basis for the anomaly. A summary of this putative effect is described, including possible molecular mechanisms involved, and suggestions for testing this hypothesis.

The Masquelet procedure gone awry

The Masquelet technique was first performed in 1986. It is a 2-stage procedure for healing of substantial bone defects, with or without the presence of infection. In the former situation, a thorough debridement of the infected site is necessary to achieve a clean cavity. A cement block is fashioned to fit into the entire defect to act as a spacer that maintains the space for grafting and reconstruction and induces a synovial-like membrane. The induced membrane avoids resorption of the bone graft and secretes growth factors, including vascular and osteoinductive factors, to promote revascularization of the graft. The membrane has an inner part that is a synovial-like epithelium and an outer part composed of fibroblasts, myofibroblasts, and collagen. It is richly vascularized. After a period of 6 to 8 weeks, the spacer is removed by incising the induced membrane that has formed. Copious bone graft, usually autologous and obtained from the iliac crest or by other means, is placed into the defect that is now lined by the induced membrane. The membrane is closed over the graft. This article describes a young patient who started on the correct path for a Masquelet procedure only to have it turn in the wrong direction. However, the problem was not recognized until 8 years after the initial injury. The situation was corrected by performing the final stage of the procedure as it was originally described.

A Novel SAT-Based Approach to Model Based Diagnosis

This paper introduces a novel encoding of Model Based Diagnosis (MBD) to Boolean Satisfaction (SAT) focusing on minimal cardinality diagnosis. The encoding is based on a combination of sophisticated MBD preprocessing algorithms and the application of a SAT compiler which optimizes the encoding to provide more succinct CNF representations than obtained with previous works. Experimental evidence indicates that our approach is superior to all published algorithms for minimal cardinality MBD. In particular, we can determine, for the first time, minimal cardinality diagnoses for the entire standard ISCAS-85 and 74XXX benchmarks. Our results open the way to improve the state-of-the-art on a range of similar MBD problems.

A comparative assessment of small-head metal-on-metal and ceramic-on-polyethylene total hip replacement

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively. A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen. In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern.

In vivo treatment sensitivity testing with positron emission tomography/computed tomography after one cycle of chemotherapy for Hodgkin lymphoma

PURPOSE

Negative [(18)F]fluorodeoxyglucose (FDG) -positron emission tomography (PET)/computed tomography (CT) after two cycles of chemotherapy indicates a favorable prognosis in Hodgkin lymphoma (HL). We hypothesized that the negative predictive value would be even higher in patients responding rapidly enough to be PET negative after one cycle. This prospective study aimed to assess the prognostic value of PET after one cycle of chemotherapy in HL and to assess the dynamics of FDG uptake after one cycle (PET1) and after two cycles (PET2).

PATIENTS AND METHODS

All PET scans were read by two blinded, independent reviewers in different countries, according to the Deauville five-point scale. The main end point was progression-free survival (PFS) after 2 years.

RESULTS

A total of 126 patients were included, and all had PET1; 89 patients had both PET1 and PET2. The prognostic value of PET1 was statistically significant with respect to both PFS and overall survival. Two-year PFS for PET1-negative and PET1-positive patients was 94.1% and 40.8%, respectively. Among those with both PET1 and PET2, 2-year PFS was 98.3% and 38.5% for PET1-negative and PET1-positive patients and 90.2% and 23.1% for PET2-negative and PET2-positive patients, respectively. No PET1-negative patient was PET2 positive.

CONCLUSION

PET after one cycle of chemotherapy is highly prognostic in HL. No other prognostic tool identifies a group of patients with HL with a more favorable outcome than those patients with a negative PET1. In the absence of precise pretherapeutic predictive markers, PET1 is the best method for response-adapted strategies designed to select patients for less intensive treatment.

Strong association between smoking and the risk of revision in a cohort study of patients with metal-on-metal total hip arthroplasty

Thus far the ability to predict who will develop early failure following the insertion of a metal-on-metal (MoM) bearing has been very limited. Our objective was to assess the effect of smoking on failure rates in patients with MoM bearing, compared with patients with ceramic-on-polyethylene (CoP) bearing. From a prospective hospital-based registry we included all primary THAs operated upon between 1/2001 and 12/2011 with MoM or CoP bearings of the same cup design and head size (28 mm). We compared revision rates through 10/2013 classified by smoking status and type of bearing. We included 1,964 patients (median age 71, 57% women), 663 with MoM and 1,301 with CoP bearing. Mean follow-up was 6.9 years (range 1.8-12.8). Revisions were required for 56 THAs. In patients with MoM bearing the adjusted incidence rate of revision among ever-smokers was four times greater than among never-smokers (95% CI 1.4-10.9). Among those with CoP bearing, the rate ratio was only 1.3 (95% CI 0.6-2.5). We found a strong association between smoking and increased failure of MoM THAs. In contrast, the association was weak for patients with CoP bearing. Smoking might be a trigger or an effect amplifier for adverse reactions to metal debris from MoM bearings.

Enhanced Partial Expansion A*

When solving instances of problem domains that feature a large branching factor, A* may generate a large number of nodes whose cost is greater than the cost of the optimal solution. We designate such nodes as surplus. Generating surplus nodes and adding them to the OPEN list may dominate both time and memory of the search. A recently introduced variant of A* called Partial Expansion A* (PEA*) deals with the memory aspect of this problem. When expanding a node n, PEA* generates all of its children and puts into OPEN only the children with f = f (n). n is re-inserted in the OPEN list with the f -cost of the best discarded child. This guarantees that surplus nodes are not inserted into OPEN. In this paper, we present a novel variant of A* called Enhanced Partial Expansion A* (EPEA*) that advances the idea of PEA* to address the time aspect. Given a priori domain- and heuristic- specific knowledge, EPEA* generates only the nodes with f = f(n). Although EPEA* is not always applicable or practical, we study several variants of EPEA*, which make it applicable to a large number of domains and heuristics. In particular, the ideas of EPEA* are applicable to IDA* and to the domains where pattern databases are traditionally used. Experimental studies show significant improvements in run-time and memory performance for several standard benchmark applications. We provide several theoretical studies to facilitate an understanding of the new algorithm.

Is there any benefit in pre-operative urinary analysis before elective total joint replacement?

Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement.

We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary.

Cite this article: Bone Joint J 2014;96-B:390–4.

Hyaluronan peroxidation is required for normal synovial function: an hypothesis

Despite widespread use of antioxidants, reactive oxygen species have important functions in normal tissues. Herein, we present an example of a physiological role for free radicals, and in particular, reactive oxygen species, that are suppressed by anti-oxidants. Free radicals catalyze the degradation of hyaluronan in synovial fluid, a tissue in which hyaluronidase activity is barely detectable. Articular cartilage requires a low oxygen environment. The process of hyaluronan peroxidation consumes significant amounts of molecular oxygen, thus keeping the tension of oxygen in the joint at a low but physiologically critical level. One concern is the change in physical activity between day and night, with periods of joint hyperemia and ischemia, respectively. Increased oxygen and the resulting oxidative stress would lead to chondrocyte dysfunction and cartilage damage. A mechanism for keeping oxygen levels low is required. We postulate that a mechanism indeed exists for the removal of excess oxygen. High-molar-mass hyaluronan turnover in synovial fluid utilizes peroxidative degradation, during which oxygen is massively consumed. The peroxidation itself may be initiated by hydrogen peroxide, which is produced by chondrocyte mitochondria, that can diffuse into the synovial fluid. The resulting decrease in available oxygen down-regulates hyaluronan peroxidation. This in turn prevents excessive oxygen consumption. It appears that free radicals and reactive oxygen species may be components of normal physiology, particularly in the synovial fluid of joints and articular cartilage. It is suggested therefore that indiscriminate use of anti-oxidants, vigorously promoted currently by health professionals and the health industry, be approached with caution.

Dual-incision approach for repair of peroneal tendon dislocation associated with fractures of the calcaneus

Dislocation of the peroneal tendons associated with calcaneus fractures should be repaired during fracture fixation to prevent complications. The only documented approach for repair is by proximal extension of the vertical limb of the lateral extensile approach to the calcaneus. However, enlarging the inherently fragile calcaneus flap places it at further risk of damage. Using a separate anterior incision to repair the dislocation, thus avoiding problems caused by excessive flap elevation, seemed intuitive. This approach proved technically effective and reliable in producing favorable outcomes in a series of 14 patients.

Jahn–Teller orbital glass state in the expanded fcc Cs3C60 fulleride

Magic-angle-spinning NMR measurements on fcc Cs₃C₆₀ to cryogenic temperatures reveal freezing-out of the C₆₀^3¬ Jahn–Teller dynamics and emergence of an electronic orbital glass state guided by the C₆₀^3¬ merohedral disorder.

Esophageal pathology: a brief guide and atlas

This article contains a brief atlas for esophageal dysphagia, with an emphasis on endoscopic evaluation. Dysphagia refers to an abnormality with food propulsion, and it may be caused by oropharyngeal or esophageal disorders. Radiological modalities, endoscopy, and manometry play an important role in both the diagnosis and management of esophageal disorders.