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We present a case of a 59-year-old woman with a history of a right-sided patellectomy. She presented with right-sided anteromedial osteoarthritis. A unicondylar knee arthroplasty was performed. In the literature, we found only a few similar cases, with varying results. The woman in this case showed excellent postoperative clinical results. We concluded that a patellectomy may not be a contraindication for unicondylar knee arthroplasty in patients with isolated medial compartment osteoarthritis. Keywords: Unicondylar, Knee, Arthroplasty, Oxford, Patellectomy, Patella

Based on the anatomy of the tibial PCL insertion site, we hypothesized that at least part of it is damaged while performing a standard tibial cut in a PCL-retaining total knee replacement. The purpose of this study was to determine and quantify the amount of resection of the tibial PCL attachment with a 9 mm tibial cut with 3 degrees of posterior slope.Twenty cadaver tibias were used. The borders of the PCL footprint were demarcated, and calibrated digital pictures were taken in order to determine the surface area. A standard tibial intramedullary guide was used to prepare and perform a tibial cut at a depth of 9 mm with 3 degrees posterior slope. After the tibial cut was made, a second digital picture was taken using the same methodology to measure the surface area of the remaining PCL insertion.The mean surface area of the intact tibial PCL footprint before the cut was 148.9 ± 25.8 mm(2) and after the tibial cut 47.1 ± 28.0 mm(2). On average, 68.8 ± 15.3 % of the surface area of the PCL insertion was removed.The results of this study, therefore, indicate that the conventional technique for tibial preparation in cruciate-retaining total knee arthroplasty can result in damage or removal of a significant part of the tibial PCL insertion.

Two small experimental headwater catchments (approx. 1500 m 2 ) were set up in an alpine spruce forest in the Alptal valley (central Switzerland). They are located at an altitude of 1200 m and receive an average of 2300 mm precipitation a year. The site is moderately impacted by atmospheric nitrogen deposition (12 kg N ha −1 yr −1 bulk deposition of inorganic N). Two different gley soils occur as patches atop a Flysch substratum. The spatial heterogeneity of the soil is related with both the microtopography of the site and the vegetation. The catchments were made by digging 80-cm deep trenches into the shallow gleyic soils. Because of the low permeability of the clay-rich subsoil, these trenches collect the lateral water flow generated in the plots. The catchments were equipped with gauging stations (V-notch weirs) and automatic runoff-proportional water samplers. Meteorological parameters, deposition, water and solute discharge were monitored during one year. A correct water balance was obtained from the experimental catchments. The leaching of inorganic nitrogen was estimated to be 4 kg N ha −1 yr −1 , mainly as nitrate. It is, however, not clear if this nitrate is leached because the ecosystem is nitrogen saturated (N in surplus of the maximal ecosystem retention). Quick preferential water flow occurs through the soil, and this may prevent nitrate from rain or snowmelt to be removed by the soil matrix before entering the water runoff pathways. Both mini-catchments showed similar biogeochemical cycles, especially for nitrogen. The time series obtained will be used as reference period for a paired-catchment experiment simulating an increased nitrogen (ammonium nitrate) deposition.

Bone marrow oedema is a common finding on MRI. Differential diagnosis includes many different clinical entities. We hereby present a case of migrating symptomatic bone marrow oedema from the medial to the lateral femoral condyle after which spontaneous resolution of both clinical and radiographic findings occurred. The role of altered weight-bearing due to therapeutic use of an unloading brace as a potential causative factor in the pathogenesis of migrating bone marrow oedema remains unclear. The literature on the topic is reviewed.