Plate fixation of extra-articular fractures of the proximal phalanx: do new implants cause less problems?

BACKGROUND: Limited range of finger motion is a frequent complication after plate fixation of phalangeal fractures. The purpose of this study was to evaluate the results of plate fixation of extra-articular fractures of the proximal phalanx using current low-profile mini-fragment-systems. METHODS: From 2006 to 2012, 32 patients with 36 extra-articular fractures of the proximal phalanx of the triphalangeal fingers were treated with open reduction and plate fixation (ORPF) using 1.2 and 1.5 mm mini-fragment systems. Patients presenting with open fractures grade 2 and 3 or relevant laceration of adjacent structures were excluded from the study. We retrospectively evaluated the rate of mal-union or non-union after ORPF, the need for revision surgery, for plate removal, and for tenolysis. Data were analyzed for further complications with regard to infections or complex regional pain syndrome (CRPS). RESULTS: No infections were noted. Five patients developed transient symptoms of CRPS. Six weeks postoperatively, total active finger motion (TAM) averaged 183°, and all 32 patients underwent formal hand therapy. At the latest follow-up or at the time of plate removal, respectively, the mean TAM improved to 213°. Extension lag of proximal interphalangeal joints was found in 67 % of all fractured fingers. Secondary surgery was necessary in 14 of 32 patients (2 corrective osteotomies, 12 plate removals including 7 procedures explicitly because of reduced mobility). CONCLUSIONS: Despite of new implant designs significant problems persist. Adhesions of extensor tendons leading to limited range of finger motion are still the most frequent complications after ORPF of proximal phalangeal fractures, even in absence of significant soft-tissue damage. LEVEL OF EVIDENCE: Therapeutic, Retrospective, Level IV.

Solitary osteochondroma of the distal radius: a rare cause of carpal tunnel syndrome diagnosed using ultrasound.

Carpal tunnel syndrome is the most common entrapment neuropathy in the upper extremity. A rare case of carpal tunnel syndrome due to solitary osteochondroma arising from the metaphysis of the distal radius is presented. Preoperative diagnosis was suspected by physical examination and high-resolution sonography and confirmed by radiographs. Surgical treatment consisted of extended open carpal tunnel release and excision of the tumor.

Endoscopically assisted nerve decompression of rare nerve compression syndromes at the upper extremity.

BACKGROUND: Besides carpal tunnel and cubital tunnel syndrome, other nerve compression or constriction syndromes exist at the upper extremity. This study was performed to evaluate and summarize our initial experience with endoscopically assisted decompression. MATERIALS AND METHODS: Between January 2011 and March 2012, six patients were endoscopically operated for rare compression or hour-glass-like constriction syndrome. This included eight decompressions: four proximal radial nerve decompressions, and two combined proximal median nerve and anterior interosseus nerve decompressions. Surgical technique and functional outcomes are presented. RESULTS: There were no intraoperative complications in the series. Endoscopy allowed both identifying and removing all the compressive structures. In one case, the proximal radial neuropathy developed for 10 years without therapy and a massive hour-glass nerve constriction was observed intraoperatively which led us to perform a concurrent complementary tendon transfer to improve fingers and thumb extension. Excellent results were achieved according to the modified Roles and Maudsley classification in five out of six cases. All but one patient considered the results excellent. The poorest responder developed a CRPS II and refused post-operative physiotherapy. CONCLUSION: Endoscopically assisted decompression in rare compression syndrome of the upper extremity is highly appreciated by patients and provides excellent functional results. This minimally invasive surgical technique will likely be further described in future clinical studies.

Angle-resolved photoelectron spectroscopy in a low-energy electron microscope.

Spectroscopic photoemission microscopy is a well-established method to investigate the electronic structure of surfaces. In modern photoemission microscopes, the electron optics allow imaging of the image plane, momentum plane, or dispersive plane, depending on the lens setting. Furthermore, apertures allow filtering of energy-, real-, and momentum space. Here, we describe how a standard spectroscopic and low-energy electron microscope can be equipped with an additional slit at the entrance of the already present hemispherical analyzer to enable an angle- and energy-resolved photoemission mode with micrometer spatial selectivity. We apply a photogrammetric calibration to correct for image distortions of the projective system behind the analyzer and present spectra recorded on Au(111) as a benchmark. Our approach makes data acquisition in energy-momentum space more efficient, which is a necessity for laser-based pump-probe photoemission microscopy with femtosecond time resolution.

Macroreplantations of the upper extremity: a series of 11 patients.

INTRODUCTION: Micro- or macroreplantation is classified depending on the level of amputation, distal or proximal to the wrist. This study was performed to review our experience in macroreplantation of the upper extremity with special attention to technical considerations and outcomes. MATERIALS AND METHODS: Between January 1990 and December 2010, 11 patients with a complete amputation of the upper extremity proximal to the wrist were referred for replantations to our department. The patients, one woman and ten men, had a mean age of 43.4 ± 18.2 years (range 19-76 years). There were two elbow, two proximal forearm, four mid-forearm, and three distal forearm amputations. The mechanism of injury was crush in four, crush-avulsion in five and guillotine amputation in two patients. The Chen classification was used to assess the postoperative outcomes. The mean follow-up after macroreplantation was 7.5 ± 6.3 years (range 2-21 years). RESULTS: All but one were successfully replanted and regained limb function: Chen I in four cases (36 %), Chen II in three cases (27 %), Chen III in two cases (18 %), and Chen IV in one patient (9 %). We discuss the steps of the macroreplantation technique, the need to minimize ischemic time and the risk of ischemia reperfusion injuries. CONCLUSION: Thanks to improvements in technique, the indications for limb preservation after amputation can be expanded. However, because of their rarity, replantations should be performed at specialist replantation centers. LEVEL OF EVIDENCE: Level IV.

Catalytic CO oxidation on Pt under near ambient pressure: A NAP-LEEM study.

A near ambient pressure low-energy electron microscope (NAP-LEEM) has recently been constructed, that allows in situ imaging of surfaces up to a pressure of 10-1 mbar. Here we report on pattern formation in catalytic CO oxidation on a Pt(110) single crystal surface and on a polycrystalline Pt foil in the 10-2 mbar range, operating the microscope in the mirror electron microscopy (MEM) and in the LEEM mode. Excitations localized at structural defects and spiral wave fragments have been observed.

The transfer of infiltration measurement results to other sewers by means of discriminant analysis.

The cost-oriented and sustainable operation of sewer systems requires a comprehensive knowledge about the infiltration situation in the catchment. Owing to the high expenditures for infiltration measurements a reliable transfer of measurement results to other sewer sections would be highly beneficial. Assuming a functional relationship between sewer characteristics and infiltration rates can be identified, such a transfer can be realised by means of classification techniques. In this paper a method is introduced which is based on discriminant analysis and which allows for a transfer of measurement results to similar sub-catchments. The method was applied using two data sets with measured or virtual infiltration rates. It yields acceptable results as a total fraction of 50% to 75% of the investigated sub-catchments was assigned correctly. Furthermore, additional information to assess the results was provided. The quality of the transfer results depends strongly on the homogeneity of the considered sub-catchments. Due to this restriction the practical applicability of the method is restricted. Nevertheless, it might be used as a screening procedure for planning of effective detailed infiltration investigations.

Entrapment of Extensor Pollicis Longus Tendon after Volar Plating of a Smith Type Pediatric Distal Forearm Fracture.

Extensor pollicis longus tendon entrapment is a rare complication of volarly displaced pediatric distal radius fractures. The few pediatric case reports have described tendon entrapment associated with conservative fracture treatment, or have been recognized at subsequent revision surgery after failure to achieve closed fracture reduction. A case of extensor pollicis longus tendon entrapment after open reduction and volar plate fixation of a pediatric distal forearm fracture is reported. This complication may also occur secondarily after open reduction and volar plating of the distal radius.

Implementation of continuous-variable quantum key distribution with composable and one-sided-device-independent security against coherent attacks.

Secret communication over public channels is one of the central pillars of a modern information society. Using quantum key distribution this is achieved without relying on the hardness of mathematical problems, which might be compromised by improved algorithms or by future quantum computers. State-of-the-art quantum key distribution requires composable security against coherent attacks for a finite number of distributed quantum states as well as robustness against implementation side channels. Here we present an implementation of continuous-variable quantum key distribution satisfying these requirements. Our implementation is based on the distribution of continuous-variable Einstein-Podolsky-Rosen entangled light. It is one-sided device independent, which means the security of the generated key is independent of any memoryfree attacks on the remote detector. Since continuous-variable encoding is compatible with conventional optical communication technology, our work is a step towards practical implementations of quantum key distribution with state-of-the-art security based solely on telecom components.

Spectromicroscope for the PHotoelectron Imaging of Nanostructures with X-rays (SPHINX): performance in biology, medicine and geology.

Several X-ray PhotoElectron Emission spectroMicroscopes (X-PEEMs) exist around the world at this time. We present recent performance and resolution tests of one of them, the Spectromicroscope for PHotoelectron Imaging of Nanostructures with X-rays (SPHINX) X-PEEM, installed at the University of Wisconsin Synchrotron Radiation Center. With this state-of-the-art instrument we demonstrate chemical analysis capabilities on conducting and insulating specimens of diverse interests, and an unprecedented lateral resolution of 10 nm with monochromatic X-rays and 7.2 nm with ultraviolet illumination.

Femoroplasty-augmentation of mechanical properties in the osteoporotic proximal femur: a biomechanical investigation of PMMA reinforcement in cadaver bones.

OBJECTIVE: To determine the feasibility of polymethyl-methacrylate injection into the osteoporotic proximal femur and its effect on the mechanical properties. DESIGN: In vitro pairwise comparison of non reinforced and reinforced bones in a load to failure loading mode. BACKGROUND: Hip fractures represent an important public healthcare problem. Continued growth in the elderly population will raise the incidence of hip fractures and their associated costs dramatically in the near future. METHODS: Twenty pairs of osteoporotic femurs were mechanically tested either in a single-limb stance configuration or simulating a fall on the greater trochanter. From each pair, one femur was augmented with bone cement, with the contralateral femur serving as a control. The surface temperature at the femoral neck was recorded until twenty minutes after injection. The fracture load and the energy absorption were calculated. The Wilcoxon signed rank test was used to test for differences in fracture load and energy absorption between the reinforced femurs and the native controls. RESULTS: Volumes of 28-41 ml of cement (mean, 36 ml) could be injected. The increase of surface temperature at the femoral neck ranged from delta18.4 to delta29.8 degrees C. For the single limb stance configurations, the peak fracture load was increased by 21%, (P < 0.002) and for the simulated fall on the hip by 82%, (P < 0.002). The corresponding values for energy absorption were +48%; and +188% (P < 0.002) respectively. CONCLUSIONS: The feasibility and mechanical effectiveness of the in vitro procedure could be demonstrated. The heat generation due to polymethyl-methacrylate polymerisation is high. RELEVANCE: Prophylactic reinforcement of the femur could become a treatment option to solve the problems with osteoporotic hip fractures in patients at risk. Reinforcement materials with less exothermic reaction need to be evaluated further and also the feasibility of fracture repair after reinforcement.

Functional-conservative treatment of extra-articular physeal fractures of the proximal phalanges in children and adolescents.

BACKGROUND: Fractures of the proximal phalanges of the fingers are common injuries in children and adolescents. The majority can be treated by closed reduction and splinting, and complications are rare. The purpose of the prospective study was to document the results of functional-conservative treatment of extra-articular physeal fractures using either a functional forearm cast or the Lucerne Cast (LuCa). METHODS: Clinical and radiographic results of 13 pediatric patients having 13 extra-articular physeal fractures (e.g., juxta-epiphyseal fractures, Salter-Harris type I or II physeal fractures) of the proximal phalanges were recorded through a minimum follow-up of 6 months. Intra-articular physeal fractures (Salter-Harris type III or IV), fractures involving the proximal interphalangeal joint (PIPJ), pathological fractures, open fractures, and concomitant injuries of the tendons were excluded. RESULTS: Fracture consolidation was achieved in all cases within 4 weeks. No palmar apex angulations, no rotational deformities, and no PIPJ extension lags could be observed. All patients achieved full total active range of motion within 3 months. CONCLUSIONS: Well-reduced extra-articular physeal fractures of the proximal phalanges can be effectively treated using functional-conservative casts. Although children may need a functional forearm cast, a LuCa is adequate in compliant adolescents.Level of Evidence The level of evidence for the study is Level II (therapeutic studies).

PROCAM Study: risk prediction for myocardial infarction using microfluidic high-density lipoprotein (HDL) subfractionation is independent of HDL cholesterol.

BACKGROUND: High-density lipoprotein (HDL) subfractions are among the new emerging risk factors for atherosclerosis. In particular, HDL 2b has been shown to be linked to cardiovascular risk. This study uses a novel microfluidics-based method to establish HDL 2b clinical utility using samples from the Prospective Cardiovascular Muenster (PROCAM) Study. METHODS: Method performance was established by measuring accuracy, precision, linearity and inter-site precision. Serum samples from 503 individuals collected in the context of the PROCAM study were analyzed by electrophoresis on a microfluidics system. Of these, 251 were male survivors of myocardial infarction (cases), while 252 individuals were matched healthy controls. HDL cholesterol, HDL 2b concentration and HDL 2b percentage were analyzed. RESULTS: This novel method showed satisfactory assay performance with an inter-site coefficient of variance of <10% for HDL 2b percentage. Parallel patient testing on 52 samples between two sites resulted in a correlation coefficient of r=0.95. Significant differences were observed in the HDL 2b subfraction between cases and controls independent of other risk factors. Including HDL 2b percentage in logistic regression reduced the number of false positives from 64 to 39 and the number of false negative cases from 48 to 45, in the context of this study. CONCLUSIONS: The novel method showed satisfactory assay performance in addition to drastically reduced analysis times and improved ease of use as compared to other methods. Clinical utility of HDL 2b was demonstrated supporting the findings of previous studies.

Case reports: aseptic femoral osteitis and sternocostal hyperostosis from SAPHO syndrome.

Synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome are characterized by peculiar bone lesions that commonly involve the anterior chest wall. Osteitis typically is the most prominent skeletal lesion seen in synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome. We present a patient with aseptic femoral osteitis and sternocostal hyperostosis. The classic clinical, radiographic, and histologic features of this syndrome are described. Diagnosis is difficult in patients with only one symptomatic bone. The lesion often is confused with suppurative osteomyelitis because of similar clinicopathologic findings. Although the optimal treatment is unclear, it is important to consider synovitis, acne, pustulosis, hyperostosis, and osteitis syndrome in the differential diagnosis of any lytic, sclerotic, or hyperostotic bone lesion to avoid unnecessary long-term antibiotic therapy.

Kyphoplasty for treatment of osteoporotic vertebral fractures: a prospective non-randomized study.

BACKGROUND: Minimally invasive augmentation techniques of vertebral bodies have been advocated to treat osteoporotic vertebral body compression fractures (VBCFs). Kyphoplasty is designed to address both fracture-related pain as well as kyphotic deformity usually associated with fracture. Previous studies have indicated the potential of this technique for reduction of vertebral body height, but there has been little investigation into whether this has a lasting effect. The current study reports on our experience and the one-year results in 27 kyphoplasty procedures (24 patients) for osteoporotic VBCFs. RESULTS: All but one patient experienced pain relief following the procedure (on VAS 1-10)--with a lasting effect over the follow-up period in 25 cases. An average vertebral kyphosis reduction of 47.7% was achieved with no loss of reduction after one year. The potential for reduction was statistically related to the pre-operative amount of kyphosis, the level treated, and the age of the fracture, but not to the age of the patient. During follow-up, one fracture adjacent to a treated level was observed. Pain relief was not related to the amount of reduction. CONCLUSION: Kyphoplasty is an effective treatment of VBCFs in terms of pain relief and durable reduction of deformity. Whether spinal realignment results in an improved long-term clinical outcome remains to be investigated.

Autologous osteochondral grafting in the knee: indication, results, and reflections.

The use of multiple autologous osteochondral plugs (mosaicplasty) for repair of articular cartilage defects is a well-accepted technique. Since 1995, the authors have used mosaicplasty to treat more than 110 patients with cartilage defects of the knee, hip, and ankle. The first 52 consecutive patients who had mosaicplasty of the knee and have an average followup of 37 months (range, 24-56 months) were examined. Indications for surgical treatment were osteochondritis dissecans, acute trauma, and posttraumatic lesions of the femorotibial joint, femoropatellar maltracking with recurrent episodes of patella dislocations, and distinct femoropatellar arthrosis. Preoperatively, cartilage defects were classified as International Cartilage Repair Society Grade III lesions in 23 patients and Grade IV lesions in 29 patients. Two years after surgery, an increased level of knee function was found in 86% of the patients. At the latest followup, improved knee function was observed in 92% of the patients. In four patients, reoperation was necessary because of graft failure. Complications and reoperation rate were related to large surface lesions. Autologous osteochondral transplantation is a valid option for the treatment of full-thickness osteochondral defects. However, the method is limited by the defect size and the number of plugs to be taken at the donor site.