Statistical Findings
Proximal Femur
The proximal femur is another common bone tumor location, accounting for 10% of osteosarcomas and 16% of Ewing's sarcomas. In one study, the survival rate for a proximal femoral prosthesis was 88% at 5 years, but this can drop significantly with time, especially if the function of the abductor muscle is poor. Another study reported the proximal femoral prosthesis survival rate of 57% at 20 years. Prosthetic reconstructions have a low rate of infection (6%), but instability can occur in as many as 28%. Allograft prosthetic composites may also be used to reconstruct the proximal femur. Composites may be more stable and have a survival advantage over prostheses, but there is a greater risk (17%) of developing an infection. Dislocation rates range from 10-15%, accounting for the most common complication of composites, but joint stability has been improved through reconstruction of the abductor mechanism and the use of bipolar components. Bipolar designs allow for motion in two places rather than one, thus providing greater stability and range of motion. 
For children, a tumor in the proximal femur might keep the pelvis from growing. Eventually he or she may need a cup, a dome-shaped liner, in the acetabulum (the hollow part of the pelvis where the femur fits).
Distal Femur
Of all osteosarcoma bone tumors found in the femur, 75% of them are located on the distal end. A prosthesis is the usual method of reconstruction. In one study, prosthesis survival was 80% at 5 years, 65% at 10 years and 53% at 20 years, while functional results have shown that 69%- 93% have good to excellent results with less than 10 years follow-up.
Proximal Tibia
Patients who have a proximal tibial lesion have the highest survival rate, with as many as 93% alive at 10 years. However, tumors in this location show a high rate of metastasis or recurrence. Prosthetic reconstruction of the proximal tibia has yielded the highest rates of infections, complications, and revisions, as well as the lowest functional scores, over any other location. At 5 years, the survival of the prosthesis is 54%, and studies have shown that 70% of patients required additional surgery at 10 years with a 25% risk of amputation. Infection can occur in more than 30% of patients, although the routine use of flaps has decreased the risk. In one study the use of a medial gastrocnemius flap decreased the risk of infection to 12%. When reconstruction is done with an allograft, 55% of patients had one or more complications, managed by both amputation and removal of the allograft.
Proximal Humerus
Limb salvage surgery involving the proximal humerus generally has good results with few complications. Reconstructions with allografts may achieve better function than those with prostheses, but the rate of infection increases with the use of allografts. As with the proximal femur, joint instability is a primary concern but has been improved through reconstruction of the abductor mechanism and the use of bipolar components.
Sources
- DiCaprio, Matthew R., M.D. and Gary E. Friedlaender, M.D. (2003, January/February.) Malignant Bone Tumors: Limb Sparing Versus Amputation. Journal of the American Academy of Orthopaedic Surgeons, 11(1), 25 - 37.
