POLIAXIAL LOCKED IMPLANTS IN THE TREATMENT OF PERI-PROSTHETIC FRACTURES OF THE FEMUR

Abstract

Implants with multidirectional locked screws have theoretical advantages in the treatment of periprosthetic fractures. In osteoporotic bone those locked plate systems with multidirectional applicable screws give a high stability. With the possibility of fixing screws in various angles, a rigid fixation in the presence of a prosthetic implant can be achieved. We concluded a retrospective study of a consecutive series of the outcome of Vancouver B1 and C femoral injuries using two specific locked implants (Straight and wave plate).

From June 1996 to December 2004 we treated 58 patients with a periprosthetic fracture of the femur with a locked plate. The mean age at the index procedure was 72.4 years, 40 patients were female (69%). In 32 cases (55.2%) we saw a hip endoprosthesis, in 21 cases (36.2%) a knee endoprosthesis and in 5 cases both (8.6%). Outcome measures were intra- and postoperative complications, bony union, degree of mobility and social status, Barthel mobility index and “stand up and go” test.

Union occurred in 56 cases (96.5%) after the index procedure. Twice the implant failed, we saw 4 general complications. The mean duration until full weight bearing status in these patients was 8.6 weeks.

At follow up 46 patients (78%) had maintained the same social status as before the fracture. Regarding the mobility status 52 patients (89%) had regained their previous level, 4 patients walking without aid before now required a cane and two patients a walking frame. The mean Barthel Index was 85 points of possible 100 and improved from 35 points at point of beginning of the rehabilitation. The mean stand-up& go time was measured as 22 seconds.

Conclusion: Overall failure rates of osteosynthesis after periprosthetic fractures of up to 35% are reported (20). With 3.5% implant related failures and 7% general complications, the presented Methods: achieve bony union and mobility in a high percentage of cases.