Open Access

Corinna Winter, Carsten Müller, Jendrik Hardes, Joachim Boos, Georg Gosheger, Dieter Rosenbaum

• Purpose The diagnosis of a malignant bone tumor in the lower limb is a risk factor for physical disability, limiting physical performance. Walking ability especially, which is essential for most activities of daily living, is limited in those patients. In the present study, the extent of limitations during the course of treatment was investigated to determine when the assessment of functional parameters is meaningful in those patients. Methods In the present study, activity levels were determined in 20 patients with a malignant bone tumor in the lower limb who received endoprosthetic replacement of the affected bone and in 20 healthy individuals. A uniaxial accelerometer was used to investigate patients at five different time points after surgery. Results Patients performed significantly less amounts and intensities of activity than control individuals at all measurements. Significant increases in the volume of activity were observed after cessation of treatment. However, the intensity of activity only showed minor increases. Patients experiencing complications of surgery revealed greater restriction than those without even 18 months after surgery. Conclusions After cessation of treatment for their disease, patients recovered markedly and showed great improvements in physical activity. However, some limitations appeared to persist. Comparisons with patients with longer follow-up revealed that meaningful functional assessment does not make sense within the first 12 months after surgery. More research is needed to show if longer follow-up periods reveal further improvements. Based on such information, it should be more promising to develop individually tailored activity recommendations and intervention programs.