Intracapsular Femoral Neck Fractures Fixation With a Dynamic Locking Plate and Screw System, Targon FN. Prospective and Retrospective Cohort Study.

Intracapsular femoral neck fractures include subcapital and transcervical fractures. They typically occur in a bimodal age distribution, with most occurring in the elderly population. The rest are the result of high energy injury in the young. Management of those fractures is based on few factors related to the patient, such as preinjury ambulatory status, age, cognitive function, and co morbidities, and on factors related to the fracture like the type of the fracture and the degree of displacement. Treatment options include nonsurgical management, fixation (percoutan, CRIF, ORIF) or arthroplasty (hemiarthroplasty, THR). Undisplaced hip fractures are defined as fractures where the inferior cortical buttress is undisplaced on the anteroposterior (AP) radiograph.[1] Undisplaced hip fractures includes fractures impacted in all degrees of valgus regardless of any angulations at the fractures' edges seen on the lateral radiographs. The fractures can be classified using either the Garden or Pauwel classifications for subcapital fracture or transcervical fractures, respectively. In displaced intracapsular femoral neck fractures like Garden type 3 and 4 or in unstable transcervcal fractures like Pauwel type 3 which are subjected to increased shear loads [2], the goals, for a physiologically young and active adult, are to preserve the femoral head, avoid osteonecrosis, and achieve union in order to avoid arthroplasty. Femoral neck fractures in young adults are associated with higher incidences of femoral head osteonecrosis [3-11] and nonunion [3, 4, 7, 12]. The reported rate of osteonecrosis after a femoral neck fracture in young patients ranges from 12% to 86% [3, 6-15]. This complication may lead to collapse of the femoral head and osteoarthritis. Salvage procedures, such as osteotomy, and other reoperations have high failure rates, and arthroplasty procedures are not ideal, given the patient's young age and higher level of activity. The achievement of an anatomic reduction and stable internal fixation is imperative. A review of the Cochrane database revealed 28 randomized or quasirandomized trials of 5,547 patients with femoral neck fractures treated with 19 different pin and/or screw constructs in a variety of configurations. [16] None of the implants had significantly superior results for outcomes related to fracture healing, osteonecrosis, wound infection, pain scores, reoperation rate, use of walking aids, periprosthetic fracture, or mortality.

Recently the Targon FN a new implant for fixation of femoral neck fracture has become available. The Targon FN implant consists of a small side plate with six locking screw ports. The two distal holes are used to fix the plate to the lateral cortex of the femur with angle stable 4.5 mm cortical screws. The proximal holes allow the implementation of up to four "TeleScrews" which cross the fracture site. These 6.5 mm screws are dynamic and allow therewith the collapse of the fracture at the femoral neck. The sliding during the collapse occurs within these screws so that a protrusion of the screws in the lateral soft tissue is prevented. The only report was reported by Martyn Parker MD and was released in Jatros Orthopädie 2008. He reported a serial of 50 femoral neck fractures, 27 (54%) of the fractures were undisplaced and 23 (48%) were displaced. There were two cases of fracture non-union; in one patient the plate became detached. One patient with a non-displaced femur neck fracture showed early radiographic signs of a possible avascular necrosis after one year. The implant was removed and the symptoms improved somewhat.

The purpose of this study is to evaluate our experience in internal fixation of intracapsular femoral neck fractures with the Targon FN implant prospectively and retrospectively in terms of the outcomes and complications associated with the treatment.