The three-dimensional architecture of bovine articular cartilage collagen and its relationship to split lines has been studied with scanning electron microscopy. In the middle and superficial zones, collagen was organised in a layered or leaf-like manner. The orientation was vertical in the intermediate zone, curving
We treated 98 patients with peri-acetabular tumours by resection and reconstruction with a custom-made pelvic endoprosthesis. The overall survival of the patients was 67% at five years, 54% at ten years and 51% at 30 years. One or more complications occurred in 58.1% of patients (54), of which infection was the most common, affecting 30% (28 patients). The rate of local recurrence was 31% (29 patients) after a mean follow-up of 71 months (11 to 147). Dislocation occurred in 20% of patients (19). Before 1996 the rate was 40.5% (17 patients) but this was reduced to 3.9% (two patients) with the introduction of a larger femoral head. There were six cases of palsy of the femoral nerve with recovery in only two. Revision or excision arthroplasty was performed in 23.7% of patients (22), principally for uncontrolled infection or aseptic loosening. Higher rates of death, infection and revision occurred in men. This method of treatment is still associated with high morbidity. Patients should be carefully selected and informed of this pre-operatively.
Long term success of percutaneous implants is dependent on soft tissue attachment to prevent infection and epithelial downgrowth, which leads to failure of the implant. Fibronectin coatings are known to enhance fibroblast attachment in vitro, but are subject to desorption from serum protein competition in vivo. This paper quantifies the binding of fibronectin to titanium alloy by silanization and the durability of this attachment when soaked in protein-rich fluid compared with adsorbed fibronectin. The biological activity of fibronectin bound to silanized titanium alloy was confirmed by analyzing cell area, morphology, immunolocalization of focal contacts, and metabolism of dermal fibroblasts. This was compared with both adsorbed fibronectin and uncoated titanium alloy. Silanized titanium alloy bound over twice the amount of fibronectin compared to untreated titanium alloy. On soaking in fetal calf serum there was no significant loss of fibronectin (p = 0.589) from the silanized surface but a significant 44% loss (p = 0.002) from untreated surfaces. Fibroblasts on silanized fibronectin had significantly larger cell areas and more vinculin focal contact markers when compared to untreated surfaces (p < 0.005). The results confirm the durability of silanized fibronectin from protein competition and bioactive effect on fibroblasts.
Impacted morsellised allografts have successfully been used to address the problem of poor bone stock in revision surgery. However, concern exists about pathogen transmission, high cost and shortage of supply of donor bone. Bone graft extenders, such as tricalciumphosphate (TCP) and hydroxyapatite (HA), have been developed to minimize the use of donor bone. In a human cadaver model we evaluated the surgical and mechanical feasibility of a TCP/HA bone graft extender during impaction grafting revision surgery.TCP/HA allograft mix increased the risk of producing a fissure in the femur during the impaction procedure, but provided a higher initial mechanical stability as compared to bone graft alone (subsidence ratio graft : TCP/HA = 2.34).If surgeons are properly trained, this type of graft extender can be viable for impaction grafting revision surgery.
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