ABSTRACT
AIM: Positioning and fixation of the bone block during revision anterior stabilization of the shoulder, in the presence of significant retained glenoid metalwork, can be challenging. We present the results of a series of patients who underwent a revision bone block procedure secured with double suture buttons using a drill guide system, the position of which was calculated from a preoperative computed tomography (CT) scan. MATERIALS AND METHODS: We undertook a revision bone block stabilization of the shoulder, using a guided double suture-button fixation, in 10 patients with significant retained glenoid metalwork from previous procedures. A preoperative CT scan was used to determine a position for the guide to allow a safe drill trajectory that would avoid any retained metalwork. A coracoid transfer was undertaken in 4 patients and an Eden-Hybinette in 6. Patients were assessed preoperatively and at final follow-up clinically and using the Oxford Shoulder Instability Score and the Subjective Shoulder Value score. Bone block position and healing was assessed by a CT scan at 6 months. The median follow-up was 36 months (range, 24-47 months). RESULTS: There were 3 female and 7 male patients with a median age of 24.5 years (17-49 years). At final follow-up, the mean Oxford Shoulder Instability Score had decreased from 25.9 (range, 21-35) to 5.8 (range, 3-14) (P < .005). The mean Subjective Shoulder Value score had risen from 87.1 (range, 10-60) to 80 (range, 60-90) (P < .05). All of the patients considered their shoulder to be stable apart from 1 patient. There had been no redislocations. The bone block positioned in the glenoid lower quadrant had healed for all of the patients on CT at 6 months. CONCLUSION: Guided suture-button fixation of the bone block during revision anterior stabilization of the shoulder, in the presence of significant retained glenoid metalwork, provides a satisfactory outcome in terms of shoulder stability, graft position, and healing.
ABSTRACT
Long-term patency of expanded polytetrafluoroethylene (ePTFE) small calibre cardiovascular bypass prostheses (<6mm) is poor because of thrombosis and intimal hyperplasia due to low compliance, stimulating the search for elastic alternatives. Wall porosity allows effective post-implantation graft healing, encouraging endothelialisation and a measured fibrovascular response. We have developed a novel poly (carbonate) urethane-based nanocomposite polymer incorporating polyhedral oligomeric silsesquioxane (POSS) nanocages (UCL-NANO) which shows anti-thrombogenicity and biostability. We report an extrusion-phase-inversion technique for manufacturing uniform-walled porous conduits using UCL-NANO. Image analysis-aided wall measurement showed that two uniform wall-thicknesses could be specified. Different coagulant conditions revealed the importance of low-temperature phase-inversion for graft integrity. Although minor reduction of pore-size variation resulted from the addition of ethanol or N,N-dimethylacetamide, high concentrations of ethanol as coagulant did not provide uniform porosity throughout the wall. Tensile testing showed the grafts to be elastic with strength being directly proportional to weight. The ultimate strengths achieved were above those expected from haemodynamic conditions, with anisotropy due to the manufacturing process. Elemental analysis by energy-dispersive X-ray analysis did not show a regional variation of POSS on the lumen or outer surface. In conclusion, the automated vertical extrusion-phase-inversion device can reproducibly fabricate uniform-walled small calibre conduits from UCL-NANO. These elastic microporous grafts demonstrate favourable mechanical integrity for haemodynamic exposure and are currently undergoing in-vivo evaluation of durability and healing properties.
