The study will review the use of massive segmental replacements in the femur, which have a porous collar with and without HA, and autologous stem cell augment. This is a randomised controlled trial.

The current surgical treatment of bone cancer patients and revision limb salvage requires usage of massive endoprosthetic bone implants. The incidence of aseptic loosening is a major cause of prosthesis failure in these patients, exploring ways to reduce such failures would allow extending longevity of massive implants in a relatively young population.

Current published literature stipulates that osteointegration could improve longevity of massive implants. Evidence suggests that usage of osteointegrated hydroxyapatite (HA) coated collar would reduce the incidence of aseptic loosening around the cemented intramedullary stem in distal femoral bone prosthesis

Inclusion Criteria:

• Bone cancer patients requiring primary or revision femoral segmental replacements and non-cancer patients requiring revision femoral segment replacement for aseptic loosening
• Male or female, aged 18 years or above
• Able to provide consent

Exclusion Criteria:

• unable/unwilling to consent
• revisions surgery due to infection
• bone cancer patients excluded from stem cell arm
• bone cancer patients with pathological fractures