Results of Revision Knee Arthroplasty With Individual Implants

Background. The presence of extensive bone defects significantly complicates the possibility of stable fixation and correct spatial positioning of the revision endoprosthesis components. The primary task of revision surgery is to restore the lost bone. The use of modern implants makes it possible to replace large metaphyseal defects of the tibia and femur, including AORI type 2B и 3 bone defects.

The aim of the study was to evaluate the long-term results of surgical treatment of patients with extensive bone defects (2B and 3 according to AORI) of the proximal tibia and/or distal femur using custom-made implants for revision knee arthroplasty.

Methods. A retrospective clinical study was performed 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 surveyed according to the international scales VAS, KSS, WOMAC and SF-36.

Results. At the follow-up examination 12 months after the surgery, 9 out of 24 patients (37.5±10%) walked without additional means of support, 10 out of 24 (41.7±10%) with a cane, 4 out of 24 (16,7±8%), walkers — 1 out of 24 (4.2±10%). There were no periprosthetic fractures during surgery and in the postoperative period. When evaluating the functional state of the knee joint, an excellent result was registered in 45.8±10% and 33.3±10%; good — in 37.5±10% and 54.2±10%; satisfactory — in 16.67±8% and 12.5±7% according to the KSS and WOMAC scales, respectively. When assessed on the VAS scale, there was a positive trend in the form of statistically significant decrease in pain in all patients (p<0.01).

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 to perform an organ-preserving surgery without loss of the statodynamic function of the lower limb. This study has limitations due to the small sample size. We believe that it is promising to study the long-term results of surgical treatment of patients with extensive bone defects (2B and 3 AORI) of the proximal tibia and /or distal femur using individually manufactured implants for revision knee replacement and a comparative analysis of these results with those using conventional implants.