Feasibility of the Inner-Side-Out Use of the LC-DCP for Periprosthetic Femoral Fracture in Total Hip Arthroplasty

Abstract

Background: The optimal technique for plate fixation to treat type B and C periprosthetic femoral fractures (PFFs) is unclear. The purpose of this study is to evaluate the radiographic results of inner-side-out limited contact dynamic compression plate (LC-DCP) to treat PFFs during or after total hip arthroplasty (THA).

Methods: This retrospective study comprised of four men and six women with an average age of 64.7 years who underwent open reduction and internal fixation with an inner-side-out LC-DCP technique to treat PFFs; the reduction was maintained preliminary with the use of contoured plate and cables, and the grooves on the undersurface of LC-DCP for limited contact was used to hold and prevent the cables from slippage during tightening the cables. There were five intraoperative and five postoperative PFFs after THA. According to the Vancouver classification, the intraoperative PFFs included type B2 in two, B3 in one and C3 in two patients while postoperative PFFs were categorized into type B1 in one, type B2 in two and type C in two patients. The mean follow-up duration was 5.9 years (range 1-10.4). We evaluated radiographic union and complications after index operation.

Results: All patients demonstrated radiographic bone union at an average follow-up duration of 4.4 months (range 3-8). Two patients showed stem subsidence after revision THA and one patient demonstrated a subsequent peri-implant fracture around the distal end of plate after union of the initial PPF; one patient underwent re-revision THA for stem loosening while another patient went through refixation for the peri-implant fracture. There was no nonunion, infection, nerve injury, or dislocation.

Conclusion: The inner-side-out LC-DCP technique showed satisfactory radiographic outcome. In certain situations where locking plates are not available, this technique might be a useful alternative for treating type B and C PFFs.

Keywords: Inner-side-out; Limited contact dynamic compression plate; Periprosthetic femoral fracture; Total hip arthroplasty.

Fig. 1

The undersurface for limited contact was facing outward and not used for its original purpose. Instead, the groove on the undersurface for limited contact can be used to hold cables and avoid slippage. a Unturned LC-DCP. b Inner-side-out LC-DCP

Fig. 2

The radiograph taken at 3 years after THA in a 72 year-old female showed Vancouver type B1 fracture in her right femur (a), which was fixed with the combination of inner-side-out LC-DCP and screw/cable combination (b). At 8 years after index operation and bone union, a type C peri-implant fracture around the distal end of plate developed (c). Since locking plate was introduced and available at the time, it was refixed with a antomical pre-shaped locking plate using less invasive plate-osteosynthesis technique. At the final follow-up, bone union was shown on the anteroposterior view of right femur (d)

Fig. 3

The LC-DCP has a distance of 16 mm between the deepest portion of the neighboring grooves, which is closer than a distance of 29 mm of the cable-ready bone plate® (Zimmer, Warsaw, USA). In addition, the LC-DCP is thinner than cable-ready bone plate®. a LC-DCP. b Cable-ready bone plate® (Zimmer, Warsaw, USA)

Fig. 4

The length of the screw head protrusion from the unturned and inner-side-out LC-DCP was 1 and 3 mm, respectively. a Unturned LC-DCP. b Inner-side-out LC-DCP

Fig. 5

The recently introduced NCB® plate system (Zimmer, Warsaw, USA) can provide angular stability with locking caps and also has grooves that can be used to hold cables and avoid slippage for treating PFFs, similar to the inner-side-out LC-DCP