Biomechanical testing of different fixation techniques for intraoperative proximal femur fractures: a technical note

Abstract

Intraoperative proximal femoral fractures (IPFF) represent a rare but challenging complication of total hip arthroplasties. They usually occur as a longitudinal split. This pilot trial aimed to compare the biomechanical primary stability of different fixation techniques for IPFF. Standardised longitudinal medial split fractures of the proximal femur (type II, Modified Mallory Classification) were created in artificial osteoporotic and non-osteoporotic composite femora after implantation of a cementless femoral stem. Five different fixation techniques were compared: cerclage band, cerclage wiring with one or two wires, and lag screw fixation with one or two lag screws. A quasi-static loading protocol was applied and failure loads were evaluated. The observed median failure loads were 4192N (3982N – 5189N) for one cerclage band, 4450N (3577N – 4927N) for one cerclage wire, 5016N (4175N – 5685N) for two cerclage wires, 6085N (5000N – 8907N) for one lag screw, and 4774N (4509N – 8502N) for two lag screws. Due to the wide range of failure loads within the experimental groups, there were no observable differences between the groups. All fixation techniques provided sufficient primary stability in osteoporotic and non-osteoporotic composite bones. Further cadaveric studies with larger sample sizes may be needed to confirm the results presented here.

Resection of the femoral neck: a new technique for the treatment of mallory type I intraoperative femoral fracture during total hip arthroplasty

“…In terms of treatment, cerclage wiring or cabling was recommended for type 1 and type 2 fractures, while fracture fixation with or without use of a long stem for type 3 fractures 10,11 . A recent biomechanical study demonstrated that there were no significant difference in the primary stability according to the fixation modalities (cerclage band, cerclage wiring, and lag screws) in Mallory type 2 femurs 27 . Therefore, for stable fixation, identification of the location and extent of fracture seems to be more imperative regardless of the fixation device when appropriately treated.…”

Resection of the femoral neck: a new technique for the treatment of mallory type I intraoperative femoral fracture during total hip arthroplasty

“…In terms of treatment, cerclage wiring or cabling was recommended for type 1 and type 2 fractures, while fracture fixation with or without use of a long stem for type 3 fractures 10,11 . A recent biomechanical study demonstrated that there were no significant difference in the primary stability according to the fixation modalities (cerclage band, cerclage wiring, and lag screws) in Mallory type 2 femurs 27 . Therefore, for stable fixation, identification of the location and extent of fracture seems to be more imperative regardless of the fixation device when appropriately treated.…”

Small design modifications can improve the primary stability of a fully coated tapered wedge hip stem

“…A distance of 70 mm between embedding and templated stem tip position was chosen independent from implant length and size to achieve a comparable bending situation [ 42 ]. The stem length varies between the stem designs as well as between the stem sizes.…”