[Distal femur replacement in extensive defects of the distal femur in revision arthroplasty]

Results of revision knee arthroplasty with individual implants

The aim of the study was to evaluate the long-term results of surgical treatment of patients with extensive bone defects (2B и 3 according to AORI) of the proximal tibia and/or distal femur using custom-made implants for revision knee arthroplasty. Material and methods. A retrospective clinical study was conducted in 24 patients who underwent revision arthroplasty using individual implants (9 femoral and 18 tibial) made on a 3D printer in the period from 2017 to 2021. T3 defect according to AORI classification was diagnosed in 12 patients (50%), F3 defect - in 1 (4.17%), F2B - in 8 (33.3%), T2B - in 6 (25%). All patients before surgery and 3, 6, 12 months after surgery were subjected to a questionnaire survey using the international scales VAS, KSS, WOMAC and SF-36. Results. At the follow-up examination 12 months after the operation, 9 out of 24 patients (37.510%) moved without additional means of support, 10 out of 24 (41.710%) with a cane, 4 out of 24 (16, 78%), walkers 1 out of 24 (4.210%). There were no periprosthetic fractures during surgery and in the postoperative period. Conclusion. The use of individual implants made using additive 3D printing technologies in revision knee arthroplasty in the presence of extensive bone defects (2B and 3 according to AORI) allows performing an organ-preserving operation without loss of the statodynamic function of the lower limb.

[Mega-prostheses in revision knee arthroplasty]

BACKGROUND

Due to a predicted increase in primary total knee arthroplasty (TKA), revision TKA will gain importance over the following years. Because the average age of patients receiving a TKA is decreasing the possible need for multiple revisions might increase as well. Despite efforts to minimize bone and soft tissue damage, the resulting bone and soft-tissue loss increases with each revision and will make the use of megaprostheses indispensable in the future.

COMPLICATIONS

The implantation of a mega-prosthesis must be carefully considered and planned, since mega-prostheses in particular are associated with an increased risk of infection and loosening. Mechanical complications, patient-specific problems and periprosthetic infections can be either the cause for or the result of revision surgery of a mega-prosthesis. In the case of a complication, only a salvage procedure, namely an arthrodesis, amputation or-if necessary-the installation of a permanent fistula is commonly recommended.