Comparison Study of 3-4-screws-internal Fixation With Multi-screw-system Targon FN for Femoral Neck Fracture

Femoral Neck Fractures

subcapital femoral fractures, transcervical femoral fractures, TARGON FN

The purpose of this study is to compare between two methods of internal fixation, the 3-4 parallel screws or the Targon FN implant in gardens type 1-2 or Pauwels type 1-2 femoral neck fractures in terms of the outcomes and complications associated with the treatment of these fractures.

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. 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. The choice of treatment of undisplaced hip fractures is contentious, especially in elderly patients. The options range from nonoperative treatment in younger patients with stable impacted fractures to primary hemiarthroplasty for frail, elderly patients.\[2\] Although some of those fracture, like impacted valgus fractures have a degree of inherent stability, internal fixation is generally recommended because nonunion rates of up to 39% have been reported with nonsurgical treatment. \[3\] In one study the authors examined 375 patients with nondisplaced intracapsular fractures treated with internal fixation \[cannulated cancellous screws (366 patients), dynamic hip screws (nine patients)\]. The authors noted a nonunion rate of 6.4% and an osteonecrosis rate of 4.0%. Age, walking ability, degree of impaction evident on the anteroposterior radiograph, and angulation on the lateral radiograph were determined to be predictive of healing complications. In this study, the conversion rate to arthroplasty was 7.7%. \[4\] Femoral neck fractures in young adults are associated with higher incidences of femoral head osteonecrosis \[5-13\] and nonunion \[5, 6, 9, 14\]. The reported rate of osteonecrosis after a femoral neck fracture in young patients ranges from 12% to 86% \[5, 8-17\]. 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. 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 therefore to compare between two methods of internal fixation, the 3-4 parallel screws or the Targon FN implant in gardens type 1-2 or Pauwels type 1-2 femoral neck fractures in terms of the outcomes and complications associated with the treatment of these fractures. we expect around 5% complications using the Targon FN implant comparing to 11% complications with the screws.

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