Caecal Volvulus in the Marden-Walker Syndrome : an Uncommon Association of Two Rare Diseases in a 4-Year Old Child. Case report

The authors report a case of caecal volvulus associated with Marden-Walker syndrome in a 4-year old girl. They point out the diagnostic difficulties of this devastating disease specially in debilitated children.     

Reprise du sport après prothèse totale d’épaule

Introduction

Shoulder arthroplasty is a common intervention and functional demands evolve with the improvement of outcomes. There is no consensus to answer demands of patients wishing to return to sport after total shoulder arthroplasty (TSA).

Effect of reverse shoulder design philosophy on muscle moment arms

This study analyzes the muscle moment arms of three different reverse shoulder design philosophies using a previously published method. Digital bone models of the shoulder were imported into a 3D modeling software and markers placed for the origin and insertion of relevant muscles. The anatomic model was used as a baseline for moment arm calculations. Subsequently, three different reverse shoulder designs were virtually implanted and moment arms were analyzed in abduction and external rotation. The results indicate that the lateral offset between the joint center and the axis of the humerus specific to one reverse shoulder design increased the external rotation moment arms of the posterior deltoid relative to the other reverse shoulder designs. The other muscles analyzed demonstrated differences in the moment arms, but none of the differences reached statistical significance. This study demonstrated how the combination of variables making up different reverse shoulder designs can affect the moment arms of the muscles in different and statistically significant ways. The role of humeral offset in reverse shoulder design has not been previously reported and could have an impact on external rotation and stability achieved post‐operatively. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:605–613, 2015.     

Glenoid loosening in response to dynamic multi-axis eccentric loading: a comparison between keeled and pegged designs with an equivalent radial mismatch

Glenoid loosening is a common failure mode observed in total shoulder arthroplasty. In an effort to isolate the affect of differing fixation techniques on loosening, an edge displacement test was conducted using two, pear-shaped, UHMWPE glenoid designs: one keel and one peg, each having a glenohumeral radial mismatch of 4.3 mm. The susceptibility of each design to loosening was established by quantifiably comparing the maximum glenoid edge displacement before and after 100,000 cycles of eccentric loading by the humeral head along both the superoinferior (SI) and anteroposterior (AP) glenoid axes. Regardless of the axes tested, the results of this study indicate that no discernable difference in edge displacement (distraction and compression) occurred before or after cyclic, eccentric loading for either the keeled or pegged glenoid designs. Additionally, each keel andpeg glenoid remained firmly fixed after testing, suggesting that either fixation technique provides sufficient resistance to edge displacement.