Abstract
Massive proximal femoral bone loss can be a complex problem, despite various modern technical and implant solutions. Due to inadequate bone stock and missing proximal fixation possibilities, including larger segmental osseous defects, the use of a mega prosthesis might become necessary. Coverage of the segmental bone loss in combination with distal fixation, can be achieved in either cemented or non-cemented techniques. Some implant types allow for additional fixation of the gluteal muscles, attached with non-absorbable sutures or synthetic mesh grafts. Although first reports about partial or even complete femoral replacement are available since the 1960's, larger case series or technical reports are rare within the literature and limited to some specialised centers. Most series are reported by oncologic centers, with necessary larger osseous resections of the femur.
The final implantation of any mega prosthesis system requires meticulous planning, especially to calculate the appropriate leg length of the implant and resulting leg length. Combination of a posterior hip with a lateral knee approach allows for the enlargement to a total femur replacement, if necessary. The lateral vastus muscle is detached and the entire soft tissues envelope can be displaced medially. After implant and cement removal, non-structural bone might be resected. Trial insertion is important, due to the variation of overall muscle tension intraoperatively and prevention of early or late dislocation. Currently the use of proximal modular systems, including length, offset and anteversion adaption, became the technique of choice for these implant systems. However, just very few companies offer yet such a complete system, which might also be expanded to a total femur solution.
We were able to evaluate our Endo-Klinik results of total-femur replacements within 100 consecutive patients in non-infected cases, after a mean follow up time of five years. There we “only” 68% patients without complications, main complications included: 13% revealed a deep infection; dislocation was found in 6%, material failure and consequent breakage in 3%, persistent patellar problems in 2% and finally 1% with peroneal nerve palsy.
These results show that a total-femur replacement is associated with a high complication rate, even in non-infected patient cohorts.
