Abstract
We have compared the cost:benefit ratio of the new type of non invasive extendable prostheses with the old type which required lengthening under general anaesthetic with an invasive procedure.
Over the past four years we have inserted 27 non invasive endoprostheses (cost £14,000). Two have failed to lengthen due to problems with the inbuilt motor. So far there have been no infections, no loosenings and no patient has required revision. The lengthenings are painless and take half an hour. In the past 25 years we inserted 175 extendable endoprostheses (cost £7,000). All lengthenings were performed under a general anaesthetic. The risk of infection was initially 20% at ten years but had decreased to 8%. Pain and stiffness arose in about 10% requiring physiotherapy or occasionally manipulation under anaesthetic.
Assuming the following costs (current NHS cost) are accurate and appropriate, then the non invasive extendable prosthesis becomes cost effective when Cost EPR < Cost old EPR + (Additional risk physio(P) x cost) + (additional cost x number of lengthenings (L)) + (additional cost of revision for infection x risk of infection (R)). 14000 < 7000 + (300 x P) + (1500 x L) + (20000 x R). Assuming a 10% need for physiotherapy, four lengthenings and a 10% risk of infection gives: 14000 < 7000 + (30) +(6000) + (2000) = 15030.
Given the high complication rate of the old type of extendable procedure and assuming there are few if any with the non invasive type, then the non-invasive endoprostheses becomes cost effective if more than three lengthenings are required. They are certainly more popular with parents and children alike!
Correspondence should be addressed to Editorial Secretary Mr ML Costa or Assistant Editorial Secretary Mr B.J. Ollivere at BOA, 35–43 Lincoln’s Inn Fields, London WC2A 3PE, England; Email: mattcosta@hotmail.com or ben@ollivere.co.uk
