Tendon Graft—Ulna Fixation in Distal Radio-Ulnar Joint Stabilisation; Biomechanical Comparison of Three Graft-Bone Fixation Methods

A common distal radio-ulnar joint (DRUJ) stabilisation procedure uses a tendon graft running from the lip of the radial sigmoid notch to the ulnar fovea and through a bony tunnel to the ulnar shaft, before being wrapped round the distal ulna and sutured to itself. Such graft fixation can be challenging and requires a considerable tendon length. The graft length could be reduced by fixing the graft to the ulna using a bone anchor or interference screw. The aim of this study was to compare the strength of three distal ulna graft fixation methods (tendon wrapping and suturing, bone anchor and interference screw). Four human cadaveric ulnae were used. A tendon strip was run through a tunnel in the distal ulna and secured by: (1) wrapping round the shaft and suturing it to itself, (2) a bone anchor and (3) an interference screw in the bone tunnel. Load to failure was determined using a custom-made apparatus and an Instron machine. Maximum failure load was highest for the bone anchor fixation (99.3 ± 23.7 N) followed by the suturing (96.2 ± 12.1 N), and the interference screw fixation (46.9 ± 5.6 N). There was no significant difference between the tendon suturing and bone anchor methods, but the tendon suturing was statistically significantly higher compared to the interference screw (P = 0.028). In performing anatomical stabilisation of the DRUJ fixation of the tendon graft to the distal ulna with a bone anchor provides the most secure fixation. This may make the stabilisation technique less demanding and require a smaller tendon graft.     

One‐ and two‐stage design proposals for a phase II trial comparing three active treatments with control using an ordered categorical endpoint

Phase II clinical trials are performed to investigate whether a novel treatment shows sufficient promise of efficacy to justify its evaluation in a subsequent definitive phase III trial, and they are often also used to select the dose to take forward. In this paper we discuss different design proposals for a phase II trial in which three active treatment doses and a placebo control are to be compared in terms of a single‐ordered categorical endpoint. The sample size requirements for one‐stage and two‐stage designs are derived, based on an approach similar to that of Dunnett. Detailed computations are prepared for an illustrative example concerning a study in stroke. Allowance for early stopping for futility is made. Simulations are used to verify that the specified type I error and power requirements are valid, despite certain approximations used in the derivation of sample size. The advantages and disadvantages of the different designs are discussed, and the scope for extending the approach to different forms of endpoint is considered. Copyright © 2008 John Wiley & Sons, Ltd.     

When work strain transcends psychological boundaries: an inquiry into the relationship between time pressure,irritation, work–family conflict and psychosomatic complaints

Against the theoretical background of the effort–recovery model and the action regulation theory, the author presents a cross‐sectional questionnaire study testing hypotheses about the relationship between work‐related time pressure, cognitive and emotional irritation, work–family conflict and psychosomatic complaints. Subjects were 576 female home care nurses. Results of a path analysis show that the relation of time pressure and psychosomatic complaints is partially mediated by experiencing a work–family conflict; also the relation of time pressure and work–family conflict is partially mediated by cognitive and emotional irritation. It is argued that cognitive and emotional irritation are fruitful concepts for a more comprehensive understanding of the relationship between work stressors and the development of strain‐based work–family conflict. Implications for the prevention of work–family conflict are outlined. Copyright © 2008 John Wiley & Sons, Ltd.