ACL tear

SummaryAnterior cruciate ligament (ACL) reconstruction has evolved considerably over the past 30years. This has largely been due to a better understanding of ACL anatomy and in particular a precise description of the femoral and tibial insertions of its two bundles. In the 1980s, the gold standard was anteromedial bundle reconstruction using the middle third of the patellar ligament. Insufficient control of rotational laxity led to the development of double bundle ACL reconstruction. This concept, combined with a growing interest in preservation of the ACL remnant, led in turn to selective reconstruction in partial tears, and more recently to biological reconstruction with ACL remnant conservation. Current ACL reconstruction techniques are not uniform, depending on precise analysis of the type of lesion and the aspect of the ACL remnant in the intercondylar notch

Empirical 3D basis for the internal density of a planet

International audienceVarious papers have discussed the forward relationships between internal density anomalies of a planet and its external gravity field. The inverse modeling, i.e. finding the internal density anomalies from the external potential is known to be highly non unique. In this research note, we explain how a 3D basis can be built to represent the internal density variations which includes a subset that explicitly spans the kernel of the forward gravity operator. This representation clarifies the origin of the non-uniqueness of the gravity sources and implies the existence of a natural minimal-norm inverse for the internal density. We illustrate these ideas by comparing a tomographic model of the mantle to the minimal norm density

Anatomic anterior cruciate ligament reconstruction: the two-incision technique

This article describes the anatomical two-incision reconstruction of anterior cruciate ligament (ACL) of knee. The major part of currently single incision tibial endoscopic techniques attempts to reproduce the most isometric anteromedial bundle of ACL. Often a relatively vertical femoral tunnel, respect to the notch, is drilled, which is not really efficacious in providing rotatory stability. The single incision technique was developed to obviate the necessity of the lateral femoral incision and dissection. This technical note describes a two-incision ACL reconstruction using an instrumentation, which avoids a large lateral femoral soft tissue dissection, and discusses the rational use of the two-incision ACL reconstruction techniqu

Slightly more births at full moon

A popular belief holds that the number of births highly increases when the moon is full. To test this belief, we use a 50-year data set of 38.7 million births in France. The signal includes quasi-periodic and discrete components that need to be subtracted. This is done using a non-linear Gaussian least-squares method. It results in residuals with very good statistical properties. A likelihood ratio test is used to reject that the residual means for the 30 days of the lunar month all equal 0 (p-value = $5 \times 10^{-5}$): the residuals show very small but highly significant variations in the lunar month due to an increase of births at full moon and the day after. The reason for the very small increase of birth at full moon is not investigated but can be suspected to result from a self-fulfilling prophecy