Polyaxial Locked Implants in the Treatment of Type Vancouver B1 Periprosthetic Fractures of the Femur: Retrospective Clinical Examination in 58 Cases with Review of the Literature.

We concluded a retrospective study of the outcomes of a consecutive series of Vancouver B1 and C femoral injuries using two specific locked implants. The study center is a dedicated trauma hospital with a large catchment area. Over a five-year period we treated 58 patients with a periprosthetic fracture of the femur with an angular stable plate, defined as the index procedure. 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 five cases both (8.6%). Outcome measures were intra- and postoperative complications, bony union, degree of mobility and social status with comparison to the preoperative status, Barthel index, and timed ''up and go'' test. Union occurred in 56 cases (96.5%) after the index procedure. Three patients were bedridden before the injury; the remainder regained full weight-bearing status. The mean duration until full weight-bearing status in these patients was 8.6 weeks (4-13). Early implant failure with proximal dislocation of the screws occurred in two cases (3.5% revision rate). At follow up, 78% had maintained the same social status as before the injury. Fifty-two patients (89%) had regained their previous level of mobility. The mean Barthel index was 85 points (70-100) out of a possible 100, and improved from a mean of 35 points at the start of rehabilitation. It decreased on average by ten points compared to the preoperative status. The mean ''up and go'' time was measured as 21.4 s. In conclusion, polyaxial plates can achieve excellent surgical results. On the other hand, patients with this type of injury exhibit a clear deterioration in their social status, especially regarding lower limb motor function and self-independence.