Endoprostheses last longer than intramedullary devices in proximal femur metastases

Abstract

Background: The proximal femur is the most common site of surgery for bone metastases, and stabilization may be achieved through intramedullary fixation (IMN) or endoprosthetic reconstruction (EPR). Intramedullary devices are less expensive, less invasive, and may yield improved function over endoprostheses. However, it is unclear which, if either, has any advantages.

Questions/purposes: We determined whether function, complications, and survivorship differed between the two approaches.

Methods: We retrospectively reviewed 158 patients with 159 proximal femur metastatic lesions treated with surgical stabilization. Forty-six were stabilized with IMN and 113 were treated with EPR. The minimum followup was 0.25 months (mean, 16 months; median, 17 months; range, 0.25-86 months).

Results: The mean Musculoskeletal Tumor Society score was 24 of 30 (80%) after IMN and 21 of 30 (70%) after EPR. There were 12 complications (26%) in the IMN group, including 10 nonunions, six of which went on to mechanical failure. There were complications in 20 of 113 (18%) of the EPR group, which consisted of 10 dislocations (9%) and 10 infections (9%). There were no mechanical failures with EPR. Both implants remained functional for the limited lifespan of these patients in each group at all time intervals. EPRs were associated with increased implant longevity compared with IMNs (100% versus 85% 5-year survival, respectively) and a decreased rate of mechanical failure (0% versus 11%, respectively) when compared with the intramedullary devices.

Conclusions: Patients with metastatic disease to the proximal femur may live for long periods of time, and these patients may undergo stabilization with either IMN or EPR with comparable functional scores and the implant survivorship exceeding patient survivorship at all time intervals. Endoprostheses demonstrate a lower mechanical failure rate and a higher rate of implant survivorship without mechanical failure than IMN devices.

Level of evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1

This Kaplan–Meier survivorship curve with 95% confidence intervals shows that both nails (p = 0.008, log-rank test) and endoprostheses (EPR) (p = 0.001, log-rank test) outlived the patients in whom they had been implanted.

Fig. 2

This Kaplan–Meier survivorship curve with 95% confidence intervals shows that there was no difference (p = 0.31) in complication-free survival between nails and endoprostheses (EPR).

Fig. 3

This Kaplan–Meier survivorship curve with 95% confidence intervals shows improved survival of the implant without mechanical failure in the endoprosthesis (EPR) group (p = 0.003).