Tightrope fixation is known method for reconstructing acromioclavicular joint and the presence of good bone stock around the two drillholes is the most important determining factor for preventing failure. Arthroscopic-assisted tightrope stabilisation involve drilling clavicle and coracoids in a straight line. This leads to eccentric drillholes with inadequate bone around it. Open tightrope fixation involves drilling holes under direct vision, independently and leading to centric hole with adequate bone around it. Our study assesses the hypothesis of tightrope fixation in relation to location of drillholes using CT-scan and cadaveric models for arthroscopic and open technique for ACJ fixation. CT-scans of 20 shoulders performed. Special software used to draw straight line from distal end of clavicle to coracoid. Bone volume around coracoid drillhole was calculated. Cadaveric shoulder specimens were dissected. The arthroscopic technique was performed under vision by drilling both clavicle and base of coracoid holes in one direction. Same specimens were used for open technique. Base of coracoid crossectioned and volume calculated.Aim
Methods
Parathyroid hormone-related peptide (PTHrP) has been shown to be an important regulator of bone remodelling1. The aim of this study was to investigate the effect of the N-terminal domain of PTHrP (1–36) on osteogenic and angiogenic gene expression in human osteoblasts (HOB) and human bone marrow stromal cells (hBMSCs). Primary hBMSC's and HOBs were cultured in standard or osteogenic media with different concentrations of PTHrP, either continuously for 8, 24, 48 h and 9 days, or with 3 cycles of intermittent exposure (24 h with PTHrP, 24 h without) over 6 days. Cell lysates were then processed for analysis of gene expression. Expression of the osteogenic markers runt-related transcription factor 2 (RUNX-2), alkaline phosphatase (ALP) and Collagen 1, and the angiogenic marker; vascular endothelial growth factor (VEGF), were measured.Introduction
Materials and Methods
The aim of this study was to establish a classification system for the acromioclavicular joint using cadaveric dissection and radiological analyses of both reformatted computed tomographic scans and conventional radiographs centred on the joint. This classification should be useful for planning arthroscopic procedures or introducing a needle and in prospective studies of biomechanical stresses across the joint which may be associated with the development of joint pathology. We have demonstrated three main three-dimensional morphological groups namely flat, oblique and curved, on both cadaveric examination and radiological assessment. These groups were recognised in both the coronal and axial planes and were independent of age.
