ABSTRACT
BACKGROUND: Porous tantalum is currently used in orthopaedic surgery for a variety of indications including soft tissue re-attachment. However, the clinical results have been variable and a previous laboratory study has suggested that tantalum may actually inhibit chick tendon fibroblasts. The influence of tantalum on human cell-types involved in soft tissue re-attachment has not been defined. METHODS: Human fibroblasts, human osteoblasts and human mesenchymal stem cells were plated on glass cover slips, half of which were coated with tantalum. Cell numbers were assessed at 1, 2, 7 and 14 days using Cyquant® assay. Cell adhesion and morphology were assessed using light microscopy at 7, 14 and 28 days. To reduce the effect of an expected rate of error, n = 4 was utilised for each cell type and the experiment was repeated twice. RESULTS: Statistically similar numbers of human osteoblasts and human mesenchymal stem cells were present at 14 days on tantalum-coated and uncoated glass cover slips, revealing no inhibitory effect on cell proliferation. More than double the number of human fibroblasts was seen on tantalum-coated cover slips at that time point (compared to controls), which was statistically significant (p < 0.0001). Morphological assessment revealed normal cell spreading and adhesion on both substrates at all time points. CONCLUSIONS: In vitro study demonstrates that Tantalum causes a significant increase in the proliferation of human fibroblasts with no quantifiable negative effects seen on fibroblast behaviour after 28 days culture. Furthermore, tantalum does not exert any inhibitory effects on the proliferation or behaviour of human osteoblasts or human mesenchymal stem cells. Tantalum could be an appropriate biomaterial for use in situations where soft tissue requires direct reattachment to implants and may stimulate soft tissue healing.
ABSTRACT
The use of tantalum is well established in orthopaedic surgery. It has a modulus of elasticity that is close to bone and a high yield and ultimate strength allowing it to be used to form large, weight-bearing constructs with a high volumetric porosity conducive to osseointegration. However, its role in soft tissue re-attachment remains undefined due to variable clinical outcomes. Successful re-attachment of tendons to tantalum mega-prostheses, in tumour and revision surgery, has been reported but several authors report almost universal failure of long term soft tissue re-attachment with tantalum patella augments when no residual bone stock is present. It is postulated that these failures are due to a lack of stability of the implants and an inhibitory effect of tantalum on soft tissue integration. Tantalum has previously been considered an excellent biomaterial for soft tissue integration based on animal studies where implants were retrieved and subjected to mechanical testing. However, clinical studies suggest that this soft tissue in-growth does not reliably tolerate the high mechanical loads that are generated in the clinical setting. Furthermore, recent laboratory evidence suggests that tantalum may in fact directly inhibit fibroblasts, limiting the potential for mature collagen fibrillogenesis. This review collates the evidence from laboratory, animal and clinical studies to inform and guide future directions in biomaterial research and to drive improved outcomes for soft tissue re-attachment surgery.
ABSTRACT
BACKGROUND: Anatomical shoulder replacement for rheumatoid arthritis (RA) is complicated by a high incidence of rotator cuff tears and glenoid erosion. This can lead to poor function and early failure. Reverse shoulder arthroplasty (RSA) has gained popularity as an alternative. This systematic review attempts to further define the role of RSA in RA. METHODS: A systematic review identified seven studies reporting outcomes of RSA in RA patients. Studies were critically appraised, and data on outcomes, complications and technical considerations were extracted and analysed. RESULTS: One hundred and twenty one shoulders were included (mean follow up 46.9 months). Consistent improvements in the main outcome measures were noted between studies. Ninety five percent of patients described excellent to satisfactory outcomes. The minimum mean forward elevation reported in each study was 115 degrees. Symptomatic glenoid loosening (1.7%), deep infection (3.3%) and revision surgery (5%) rates were no higher than for a population of mixed aetiologies. DISCUSSION: Previous concerns regarding high pre- and peri-operative complication and revision rates in RA patients were not shown to be valid by the results of this review. Although associated cuff tears are common and glenoid bone loss can increase the technical complexity of surgery, RSA provides consistent and predictable improvements in key outcome measures and the revision and complication rates do not appear to be higher than reported in a large population of mixed aetiologies. CONCLUSION: The contemporary literature shows that RSA is a safe, effective and reliable treatment option in RA patients.
