THE RISK OF AMPUTATION FOLLOWING LIMB SALVAGE SURGERY WITH ENDOPROSTHETIC REPLACEMENTS

Abstract

Endoprosthetic Replacements are one of the most commonly used types of limb salvage following surgical excision of bone tumours. The advantages of Endoprosthetic Replacements are their initial reliability and the rapid restoration of function along with their ready availability. The problems with Endoprosthetic Replacements are the long term problems of wear, loosening, infection and mechanical failure. Increasing and insolvable problems may lead to the necessity for amputation. This paper assesses the risk of amputation following Endoprosthetic Replacement.

A total of 1262 patients have undergone Endoprosthetic Replacement surgery at our centre in the past 34 years. They have a total of 6507 patient years of follow up. A total of 112 patients have had subsequent amputation (8. 9%). The reasons for amputation were local recurrence in 71(64. 4%), infection in 38(33. 9%), mechanical failure in 2(1. 8%) and continued pain in 1 case (0. 8%). The risk of amputation was greatest in the proximal tibia 15. 5% (n=38/246), followed by pelvis 10. 2%(5/49), and femur 7. 4% (n=58/784), whilst the risk of amputation was least in the humerus at 6. 4% (n= 1l/182). The time to amputation varied from 2 days to 16. 3 7 years, with a mean of 31 months. The risk of amputation decreased with time although 10% of the amputations took place more than 5 years after implantation.

The greatest risk of amputation is in the first 5 years and is due to local recurrence, whilst infection poses the next greatest threat. The risk decreases with time. Attempts to control both local recurrence and infection will decrease the need for amputation. Late failure of the endoprosthetic replacements, even in young patients does not seen to be a major cause of amputation thus far.