[Femoral nailing using a helical nail shape (LFN(®))]. / Marknagelung des Femurs mit einem helikalen Implantat (LFN(®)).

OBJECTIVE: Antegrade femoral nailing through a greater trochanteric entry portal avoids damage to the proximal external rotators and to the ramus profundus of the medial femoral circumflex artery, furthermore eases insertion in adipose subjects. However a helical nail shape is necessary for this pathway because bending in two perpendicular planes has to be passed by the nail. INDICATIONS: All femoral shaft fractures suitable for antegrade nailing (type 32-A/B/C). Additional femoral neck fractures (type 31-B) by using proximal Recon-interlocking screws. CONTRAINDICATIONS: The common contraindications for femoral nailing. In certain subtrochanteric fractures (Type 32-A/B) the proximal femoral nail may be favorable. SURGICAL TECHNIQUE: General or spinal anesthesia. Supine position with flexion/abduction of the contralateral leg in order to facilitate fluoroscopy of the proximal femur in a true lateral view. Closed reduction of length and axis. Measurement of length and diameter of the nail using a radiolucent ruler. Dorsolateral approach to the greater trochanter. Insertion of the guide wire 10 mm lateral to the trochanteric tip (anteroposterior view) and in the middle third of the trochanter (lateral view). Reaming of the insertion point using a flexible reamer. If reaming of the entire medullary canal is desired, this should be done using a long intramedullary guide wire in combination with a long flexible reamer. Insertion of the nail starts in an anterior position and ends in a lateral position of the insertion instrument, so a 90° external rotation of the nail occurs during insertion. Proximal interlocking is performed using the guide of the insertion instrument. Check interfragmentary rotation. Distal interlocking using a radiolucent drill device. POSTOPERATIVE MANAGEMENT: Depends on the fracture shape: stable interfragmentary support may allow early full weight bearing. Otherwise, reduced weight bearing is recommended for at least 6 weeks. RESULTS: In a prospective mulicentric study, 227 helical femoral nails were used for antegrade femoral nailing. Follow-up after 12 month was available in 74 %. Surgeons' rating for ease of identifying entry site was excellent or good in 89 %. Functional and radiological results after 12 months do not prove significant benefits over conventional antegrade femoral nails.

[Experiences with a helical femoral nail (LFN®). A multicenter study]. / Erfahrungen mit einem helikalen Femurmarknagel (LFN®). Eine multizentrische Studie.

INTRODUCTION: Antegrade intramedullary nailing is the method of choice in most femoral shaft fractures. The trochanteric entry portal of classic femoral nails is in close proximity to the piriformis tendon, the gluteus minimus tendon, the obturator tendons, and the medial femoral circumflex artery. Nail insertion lateral to the tip of the greater trochanter may be more favorable but needs the use of a helical implant. MATERIAL AND METHODS: Measurement of the reamer pathway through an entry point lateral to the superior trochanteric border was performed with a three-dimensional motion tracking sensor in human cadaveric femurs. These results provided a scientific rationale for the design of a helical femoral nail (LFN®). In a prospective multicenter study a total of 227 femoral shaft fractures were treated by nailing with the LFN. Patients were followed at 3 months (n=193) and 12 months (n=167). RESULTS: The ease of defining the entry point and inserting the nail was rated as"very good and good" by 90% of the surgeons. Intraoperative technical complications included incomplete reduction (14%), additional iatrogenic fractures (6%), and difficulties in interlocking (3.5%). At the 1-year follow-up, delayed unions were seen in 10%, secondary loss of reduction in 3%, and deep infection in 1.8% of the patients. Angular malalignment of more than 5° was seen in 5%, mostly in valgus. A normal walking capacity was seen in 68% and normal active hip flexion in 45%. CONCLUSION: The results obtained in this study during 1 year do not provide evidence for an advantage of the LFN over conventional antegrade femoral nails.