Preservation of lesser metatarsophalangeal joints in rheumatoid forefoot reconstruction

A standard rheumatoid forefoot reconstruction consists of arthrodesis of the first metatarsophalangeal (MTP) joint and resection arthroplasty of the lesser metatarsal heads. However, preservation of the metatarsal heads has gained renewed interest since the medical treatment of rheumatoid arthritis has improved dramatically.

Carbon sequestration in Himalaya's alpine meadows: Mitigating cropping encroachment on pastures in Northern Pakistan

Rangelands store about 30% of the world’s carbon and support over 120 million pastoralists globally. Adjusting the management of remote alpine pastures bears a substantial climate change mitigation potential that can provide livelihood support for marginalized pastoralists through carbon payment. Landless pastoralists in Northern Pakistan seek higher income by cropping potatoes and peas over alpine pastures. However, tilling steep slopes without terracing exposes soil to erosion. Moreover, yields decline rapidly requiring increasing fertilizer inputs. Under these conditions, carbon payment could be a feasible option to compensate pastoralists for renouncing hazardous cropping while favoring pastoral activities. The study quantifies and compares C on cropped and grazed land. The hypothesis was that cropping on alpine pastures reduces former carbon storage. The study area located in the Naran valley of the Pakistani Himalayas receives an annual average of 819 mm of rain and 764 mm of snow. Average temperatures remain below 0°C from November to March while frost may occur all year round. A total of 72 soil core samples were collected discriminating land use (cropping, pasture), aspect (North, South), elevation (low 3000, middle 3100, and high 3200 m a.s.l.), and soil depth (shallow 0-10, deep 10-30 cm). Thirty six biomass samples were collected over the same independent variables (except for soil depth) using a 10x10x20 cm steal box inserted in the ground for each sample. Aboveground biomass and coarse roots were separated from the soil aggregate and oven-dried. Soil organic carbon (SOC) and biomass carbon (BC) were estimated through a potassium dichromate oxidation treatment. The samples were collected during the second week of October 2010 at the end of the grazing and cropping season and before the first snowfall. The data was statistically analyzed by means of a one-way analysis of variance. Results show that all variables taken separately have a significant effect on mean SOC [%]: crop/pasture 1.33/1.6, North/South 1.61/1.32, low/middle/high 1.09/1.62/1.68, shallow/deep 1.4/1.53. However, for BC, only land use has a significant effect with more than twice the amount of carbon in pastures [g m-2]: crop/pasture 127/318. These preliminary findings suggest that preventing the conversion of pastures into cropping fields in the Naran valley avoids an average loss of 12.2 t C ha-1 or 44.8 t CO2eq ha-1 representing a foreseeable compensation of 672 € ha-1 for the Naran landless pastoralists who would renounce cropping. The ongoing study shall provide a complete picture for carbon payment integrating key aspects such as the rate of cropping encroachment over pastures per year, the methane leakage from the system due to livestock enteric fermentation, the expected cropping income vs. livestock income and the transaction costs of implementing the mitigation project, certifying it, and verifying carbon credits. A net present value over an infinite time horizon for the mitigation scenario shall be estimated on an iterative simulation to consider weather and price uncertainties. The study will also provide an estimate of the minimum price of carbon at which pastoralists would consider engaging in the mitigation activity.

Island Invasion by a Threatened Tree Species: Evidence for Natural Enemy Release of Mahogany (Swietenia macrophylla) on Dominica, Lesser Antilles

Despite its appeal to explain plant invasions, the enemy release hypothesis (ERH) remains largely unexplored for tropical forest trees. Even scarcer are ERH studies conducted on the same host species at both the community and biogeographical scale, irrespective of the system or plant life form. In Cabrits National Park, Dominica, we observed patterns consistent with enemy release of two introduced, congeneric mahogany species, Swietenia macrophylla and S. mahagoni, planted almost 50 years ago. Swietenia populations at Cabrits have reproduced, with S. macrophylla juveniles established in and out of plantation areas at densities much higher than observed in its native range. Swietenia macrophylla juveniles also experienced significantly lower leaf-level herbivory (~3.0%) than nine co-occurring species native to Dominica (8.4–21.8%), and far lower than conspecific herbivory observed in its native range (11%–43%, on average). These complimentary findings at multiple scales support ERH, and confirm that Swietenia has naturalized at Cabrits. However, Swietenia abundance was positively correlated with native plant diversity at the seedling stage, and only marginally negatively correlated with native plant abundance for stems ≥1-cm dbh. Taken together, these descriptive patterns point to relaxed enemy pressure from specialized enemies, specifically the defoliator Steniscadia poliophaea and the shoot-borer Hypsipyla grandella, as a leading explanation for the enhanced recruitment of Swietenia trees documented at Cabrits.

Lesser tuberosity osteotomy for total shoulder arthroplasty. Surgical technique

BACKGROUND: Recent studies have suggested that tenotomy and repair of the subscapularis tendon carried out for anterior approaches to the shoulder can be followed by failure of the tendon repair and by changes resulting in permanent loss of subscapularis function. We hypothesized that release of the subscapularis with use of a superficial osteotomy of the lesser tuberosity followed by repair of the two opposing bone surfaces would lead to consistent bone-to-bone healing, which would be possible to monitor radiographically, and would lead to satisfactory clinical and structural outcomes. METHODS: Thirty-nine shoulders in thirty-six consecutive patients who, at an average age of fifty-seven years, had undergone total shoulder replacement through an anterior approach involving an osteotomy of the lesser tuberosity were evaluated at an average of thirty-nine months. Assessment included a standardized interview and physical examination, scoring according to the system described by Constant and Murley, and imaging with conventional radiography and computed tomography to assess healing of the osteotomy site and changes in the subscapularis. RESULTS: The osteotomized tuberosity fragment healed in an anatomical position in all shoulders, and no cuff tendon ruptures were observed. At the time of follow-up, thirty-three (89%) of thirty-seven shoulders evaluated with a belly-press test had a negative result and twenty-seven (75%) of thirty-six shoulders evaluated with a lift-off test had an unequivocally normal result. Fatty infiltration of the subscapularis muscle increased after the operation (p < 0.0001) and was at least stage two in eleven (32%) of thirty-four shoulders. The fatty infiltration had progressed by one stage in eight (24%) of the thirty-four shoulders, by two stages in five shoulders (15%), and by three stages in two shoulders (6%). CONCLUSIONS: Osteotomy of the lesser tuberosity provides an easy anterior approach for total shoulder replacement and is followed by consistent bone-to-bone healing, which can be monitored, and good subscapularis function. In the presence of documented anatomical healing of the osteotomy site, postoperative fatty infiltration of the subscapularis muscle remains unexplained and needs to be investigated further as it is associated with a poorer clinical outcome.

The lesser trochanter as a cause of hip impingement: pathophysiology and treatment options

Impingement of the lesser trochanter on the ischium or the posterior acetabular rim is not a frequent pathology, but has recently received increased recognition. We have seen 14 cases over a period of 14 years, but concentrate on eight hips showing complex deformities revealing similar characteristics. All eight hips had a residual Perthes or a Perthes-like disease with an elliptically deformed femoral head, but a congurent joint a short or absent femoral neck, a high riding greater trochanter, and a reduced vertical distance between the head and the lesser trochanter. Impingement took place between the lesser trochanter and the ischium or the posteroinferior acetabular border, but was hardly recognisable due to the predominant intraarticular impingement of the nonspherical femoral head and the extraarticular impingement of the greater trochanter. In three cases the impingement showed reproducible subluxation of the hip. While in our hips, excision was the preferred treatment for impingement due to an oversized lesser trochanter, distal advancement was used in the hips with the Perthes morphology; the surgical time was not longer. The overall clinical results in this group however were dominated by a substantial increase in the range of motion (ROM), dependent mainly on the achieved contour of the femoral head and the relative lengthening of the neck. Strength of active hip flexion was normal. Recurrent subluxation disappeared and no complications were recorded.

Deciphering High-Pressure metamorphism in collisional context using microprobe-mapping methods : application to the Stak eclogitic massif (NW Himalaya)

The Stak massif, northern Pakistan, is a newly recognized occurrence of eclogite formed by the subduction of the northern margin of the Indian continent in the northwest Himalaya. Although this unit was extensively retrogressed during the Himalayan collision, records of the high-pressure (HP) event as well as a continuous pressure-temperature (P-T) path were assessed from a single thin section using a new multiequilibrium method. This method uses microprobe X-ray compositional maps of garnet and omphacitic pyroxene followed by calculations of ∼200,000 P-T estimates using appropriate thermobarometers. The Stak eclogite underwent prograde metamorphism, increasing from 650 °C and 2.4 GPa to the peak conditions of 750 °C and 2.5 GPa, then retrogressed to 700–650 °C and 1.6–0.9 GPa under amphibolite-facies conditions. The estimated peak metamorphic conditions and P-T path are similar to those of the Kaghan and Tso Morari high- to ultrahigh-pressure (HP-UHP) massifs. We propose that these three massifs define a large HP to UHP province in the northwest Himalaya, comparable to the Dabie-Sulu province in China and the Western Gneiss Region in Norway.

Stable-Isotopic Composition of Precipitation Over the Northern Slope of the Central Himalaya

Stable-water-isotope data (deltaD and delta(18)O) from three groups of samples (fresh-snow and snow-pit samples collected on Qomolangma (Mount Everest) and Xixabangma during field seasons 1997,1998 and 2001, and precipitation samples collected at Tingri station during summer 2000) are presented and used to survey the isotopic composition of precipitation over the northern slope of the central Himalaya. Multi-year snow-pit samples on Qomolangma have a local meteoric water-line (slope = 8) close to the global value. Deuterium excess (d = deltaD - 8delta(18)O) values at Tingri are much lower than those in fresh snow from Qomolangma, probably due to differences in moisture source and air-mass trajectories as well as local weather conditions. There is no obvious seasonal trend for d values in the Qomolangma region. A negative relationship exists between delta(18)O and d values in both fresh snow on Qomolangma and precipitation at Tingri. Fresh-snow samples collected from different altitudes on Xixabangma allow us to investigate the altitude effect on delta(18)O values in snow. Of four storm events, only one has an obvious altitude effect on delta(18)O variation and a very low gradient of -0.1% per 100 in elevation.

Snow Accumulation Rate on Qomolangma (Mount Everest), Himalaya: Synchroneity With Sites Across the Tibetan Plateau on 50-100 Year Timescales

Annual-layer thickness data, spanning AD 1534-2001, from an ice core from East Rongbuk Coll on Qomolangma (Mount Everest, Himalaya) yield an age-depth profile that deviates systematically from a constant accumulation-rate analytical model. The profile clearly shows that the mean accumulation rate has changed every 50-100 years. A numerical model was developed to determine the magnitude of these multi-decadal-scale rates. The model was used to obtain a time series of annual accumulation. The mean annual accumulation rate decreased from similar to 0.8 m ice equivalent in the 1500s to similar to 0.3 m in the mid-1800s. From similar to 1880 to similar to 1970 the rate increased. However, it has decreased since similar to 1970. Comparison with six other records from the Himalaya and the Tibetan Plateau shows that the changes in accumulation in East Rongbuk Col are broadly consistent with a regional pattern over much of the Plateau. This suggests that there may be an overarching mechanism controlling precipitation and mass balance over this area. However, a record from Dasuopu, only 125 km northwest of Qomolangma and 700 m higher than East Rongbuk Col, shows a maximum in accumulation during the 1800s, a time during which the East Rongbuk Col and Tibetan Plateau ice-core and tree-ring records show a minimum. This asynchroneity may be due to altitudinal or seasonal differences in monsoon versus westerly moisture sources or complex mountain meteorology.

Preliminary Results from the Chemical Records of an 80.4 M Ice Core Recovered from East Rongbuk Glacier, Qomolangma (Mount Everest), Himalaya

High-resolution chemical records from an 80.4 m ice core from the central Himalaya demonstrate climatic and environmental changes since 1844. The chronological net accumulation series shows a sharp decrease from the mid-1950s, which is coincident with the widely observed glacier retreat. A negative correlation is found between the ice-core delta(18)O record and the monsoon precipitation for Indian region 7. The temporal variation of the terrestrial ions (Ca2+ and Mg2+) is controlled by both the monsoon precipitation for Indian regions 3,7 and 8, located directly south and west of the Himalaya, and the dust-storm duration and frequency in the northern arid regions, such as the Taklimakan desert, China. The NH4+ profile is fairly flat until the 1940s, then substantially increases until the end of the 1980s, with a slight decrease during the 1990s which may reflect new agricultural practices. The SO42- and NO3- profiles show an apparent increasing trend, especially during the period 1940s-80s. Moreover, SO42- concentrations for the East Rongbuk Glacier core are roughly double that of the nearby Dasuopu core at Xixabangma, Himalaya, due to local human activity including that of climbing teams who use gasoline for cooking, energy and transport.

Lesser Ury

Lothar Brieger