Clinical Outcome After Replacement of Distal Femur/Proximal Tibia in a Heterogeneous Patient Cohort: Function Following Tumour, Trauma, and Loosening.

ABSTRACT

BACKGROUND: Distal femur and proximal tibia replacements as limb-salvage procedures with good outcome parameters for patients with tumours have been broadly described. However, the overall midterm outcome in a mixed, heterogeneous patient collective is still unclear. PATIENTS AND METHODS: We retrospectively analysed 59 consecutive patients (33 for primary and 26 for revision surgery) between 1998 and 2017. Indication for implantation was tumour (n=16), periprosthetic fracture (n=14), traumatic fracture (n=14), infection (n=10), aseptic loosening (n=3), and pathological fracture (n=2). The mean follow-up duration was 3 years. Clinical functions were evaluated by Toronto Extremity Salvage Score and Knee Society Score. Knee extension and flexion force were measured. RESULTS: The overall survival rate of arthroplasties was 59% (n=35). Major complications were observed in 36 (61%) patients. During the follow-up period, 14 (24%) patients died. We recorded periprosthetic joint infection in 21 (36%) patients, recurrence of tumour in two (3%), and aseptic implant failure in three (5%). The mean Toronto Extremity Salvage Score was 66±33, and the mean Knee Society Score was 49±30. The mean extension force on the operated side was significantly reduced at 60° and 180° compared to the healthy side (p=0.0151 and p=0.0411, respectively). CONCLUSION: Distal femur and proximal tibia replacements showed limited clinical function in a heterogeneous patient collective. Indication for implantation should be considered carefully.