Retrograde entry portal for cephalomedullary nailing in difficult subtrochanteric fractures

Highlights

• Achieving a perfect entry point is one of the most important steps in nailing a subtrochanteric fracture. The proximal femur deformity, certain patient and fracture characteristics make antegrade conventional way of creating an entry point often difficult in these fractures.

• Retrograde entry portal technique makes use of the proximal femur deformity in subtrochanteric fractures to create the entry point before fracture reduction.

• The natural trajectory when using the retrograde technique is lateral - distal to proximal - medial due to the abducted proximal fragment. This makes it easy to achieve a more medial entry point when desired without difficulties.

• The technique requires an open approach which has been shown to be achieve fracture union rates comparable with closed techniques

• The open approach also allows direct reaming of the thickened lateral endosteal cortex in atypical fractures, which is an important step to prevent varus deformity in such fractures

Abstract

An entry point medial to the tip of the greater trochanter is considered optimal for antegrade femur nailing. The deforming forces in a subtrochanteric fracture often make it difficult to establish a perfect entry point during antegrade cephalomedullary nailing. To overcome this problem, we report a simple technique of making a retrograde entry portal for select difficult subtrochanteric fractures. The technique was used in 12 subtrochanteric fractures. Our indications were morbid obesity, revision nailing and atypical fractures. The technique involves creating a nail entry portal through the fracture from distal to proximal taking advantage of the abducted proximal fragment. Fracture reduction and nail insertion then proceeds in a standard manner. Additional reaming of the thick endosteal lateral cortex through the fracture was performed in atypical fractures. Satisfactory fracture reduction was achieved in all patients and 11 out of the 12 fractures united in the series. 1 patient developed an infected nonunion and was considered failure of treatment. The retrograde entry portal is a valuable alternative method that can be considered in nailing of difficult subtrochanteric fractures to establish an ideal entry point and nail trajectory.

Introduction

The short proximal segment in subtrochanteric fractures is subjected to severe deforming forces by the inserting pelvi-femoral muscles often resulting in flexion, abduction and external rotation [1]. This makes reduction and cephalomedullary nailing of these fractures difficult. To nail such fractures successfully, it is important to start with a proper entry portal after achieving a satisfactory fracture reduction either by closed or open methods. The concept of an ideal entry point for nailing of proximal femur fractures has evolved over a period of time. Though nails with proximal bends allow a more lateral entry to facilitate nail insertion, it has also been shown that it can lead to lateral fracture gapping and unacceptable varus deformity [2]. It can also increase strain and incidence of fissuring at the thin lateral cortex and the possibility of medial cortical impingement [3]. The appropriate entry portal recommended with contemporary nail designs is just medial to the tip of the greater trochanter in the coronal plane [4]. This more medialised entry point has been shown to work best with most of the modern nail designs in terms of clinical outcome [5,6]. In spite of this current knowledge on nailing of subtrochanteric fractures, sometimes it can still be difficult to achieve a perfect entry point and nail trajectory in select patients such as ones who are morbidly obese, patients with atypical fractures and in cases which had been previously nailed [7], [8], [9]. To overcome this problem, we report a technique of creating a trans-fracture retrograde entry portal for establishing an ideal start point and nail trajectory in such difficult subtrochanteric fractures.