Session VIII - Femur/Knee

*The Old Begets the New: Trochanteric Nail Insertion for Femoral Shaft Fractures, Revisited

D. Scott Devinney, DO; Roy W. Sanders, MD (a,c,e-Smith + Nephew); Dolfi Herscovici, Jr., DO; Anthony F. Infante, DO; Tampa General Hospital, Tampa, Florida, USA

Purpose: Intramedullary (IM) nailing of femoral shaft fractures through a trochanteric starting point with the patient in a lateral decubitus position was popularized in the 1940s by G. Kuntscher. Large diameter nails (without locks) were used to obtain an interference fit to secure femoral shaft fracture stabilization when shaft comminution was present. This technique often resulted in proximal femoral fractures and led to the development of the piriformis fossa as the primary point of entry for antegrade femoral nail insertion. This entry is often difficult in the supine position, which has now become the standard position for femoral antegrade nail insertion. A new IM trochanteric antegrade nail (T.A.N., Trigen System, Smith & Nephew, Memphis, Tennessee) was developed as an attractive alternative to standard femoral antegrade nails. With patients undergoing supine nail insertion, it was thought that there would be significant ease in locating the entry point, especially in the obese patient, with the potential for both decreased operative time and surgeon exposure to radiation. This institutional review board-approved study was performed to evaluate the results of use of this device.

Methods: The T.A.N. nail is a cannulated, closed-section, titanium alloy interlocking nail with a proximal diameter of 13 mm and a 5° valgus bend. Standard antegrade locking into the lesser trochanter, as well as reconstruction locks at 135° into the head and neck are possible in the same nail, which, as a result, requires separate right and left implants. Participation in this nonrandomized study was at the discretion of the surgeon and agreement by the patient. Thirty-two patients between the ages of 14 and 97 years (average, 45.4) with 32 femoral shaft fractures were included in this study. Twenty fractures were a result of a high-energy injury requiring a trauma alert; 27 fractures were closed and 5 open (2 II,1 IIIA, 2 IIIB). Eleven patients were moderately obese (250 to 350 lbs.), and 3 weighed more than 400 lbs. All were operatively treated in the supine position; 23 fractures required reamed insertion and 9 did not. All nails were locked proximally and all but three, distally. All fractures were evaluated for time to clinical and radiographic union. Clinical union was defined as full painless weightbearing, radiographic union required bridging callus across all four cortices. Patients underwent physical and radiographic examination and completed hip-specific and SF-36 functional outcome instruments at a minimum of 1 year after the procedure.

Results: Twenty-four of 32 fractures were available for follow-up at a minimum of 1 year (range, 1.0 to 2.1). The mean time to radiographic healing was 8.4 weeks (range, 7 to 16). Union occurred in all but one fracture that required dynamization at 12 weeks, to achieve an overall union rate of 100%. No patient sustained a malunion (>10° in any plane). Importantly, ease of insertion, even in the morbidly obese patients, was evident >from surgeon satisfaction forms. No iatrogenic proximal femur fractures or fissures were sustained during nail insertion. Operative and fluoroscopy times were not accurately recorded because of confusion regarding inclusion of positioning time, and these data were not included the study. There were no wound infections. Clinically nonrelevant heterotopic bone was evident on radiographic examination in five hips, (four Brooker 1, one Brooker 2). Clinically relevant pain was reported as slight by four patients and moderate in one; two of five patients isolated the pain to the proximal locking screw. Screw removal resolved the pain of one patient. No patient reported severe hip pain. The average Harris Hip Score was 77.6. Range of motion averages were equal to that of the normal side in all cases. Video gait analysis revealed symmetrical walking in 21 patients. The remaining three had a slight Trendelenburg gait; two of these were octogenarians.

Conclusion: Intramedullary nailing of femoral shaft fractures through the piriformis fossa with the patient in the lateral position remains the standard. However, use of a specially designed small proximal diameter nail for trochanteric insertion when the patient is placed in the supine position resulted in equally high union rates with no significant complications in our series. The more subcutaneous starting point also appeared to facilitate nail insertion, especially in obese patients, and had a very high surgeon satisfaction rate. Our results indicated an excellent rate of union, with no malunions. Pain was no greater in the affected hip than that described for conventional antegrade nailing through the piriformis fossa. No correlation was observed between the presence of heterotopic bone (Brooker 1 and 2) and the presence of pain or decreased hip motion. As in all cases of internal fixation, prominent implants causing discomfort should be removed after fracture union. Further analysis, including a multi-center randomized prospective study comparing T.A.N. with conventional nailing is now underway.