[Periprosthetic supracondylar femoral fractures: LISS or retrograde intramedullary nailing? Problems with the use of minimally invasive technique].

Retrograde intramedullary locking nailing as well as the LIS system are propagated as minimally invasive treatment options for distal femoral fractures following total knee arthroplasty. In a retrospective study, we reviewed the clinical results after operative treatment of 18 periprosthetic supracondylar femoral fractures. The fracture was stabilized with the less invasive stabilization system (LISS) in nine patients (average age: 80.3 years) and with a retrograde intramedullary locking nail in the remaining nine patients (average age: 76.8 years). The mean follow-up was 18.2 months (6-35 months). We did not find significant differences concerning the operation time (nailing 99.8 min vs 102.3 min with the LISS) or the length of stay in the hospital (nailing 10.6 days vs 12.7 days with the LISS). In one patient of the nailing group we found a valgus malalignment of 18 degrees. Seven patients in each group were satisfied with the clinical results. In one patient of the LISS group a revision due to an infection was necessary. In one patient of the nailing group a reosteosynthesis had to be performed. To sum up, both systems are useful tools in the treatment of dislocated periprosthetic fractures and both systems are not without any problems. However, under special consideration of the complications we found in our study, the LISS seems to be a better alternative in osteoporotic bone with a small distal fragment. The choice of the optimal implant should therefore depend on the type of fracture and knee arthroplasty, the type of bone, and the experience of the surgeon.