Session IV - Femur

Antegrade vs. Retrograde Femoral Nailing: A Comparison of Canal-Sized Implants

Robert F. Ostrum, MD; Brian Davison, MD; Attila Poka, MD, Grant Medical Center, Columbus, OH

Purpose: To prospectively compare the results of antegrade and retrograde reamed femoral nailing with respect to fracture union, knee function, operative time, and blood loss.

Methods: All femoral fractures treated with an intramedullary nail were randomized by medical record number to receive either an antegrade (Group A) or retrograde (Group R) implant. The femurs were reamed until cortical chatter was encountered or maximum of 13.5mm. We selected the diameter of the implant to be 1mm or 1.5mm less than the last reamer. All nails were 10, 11, or 12 millimeters in diameter. All nails were locked both proximally and distally. The following data was collected prospectively on all patients: operative time, blood loss, nail characteristics, presence and grade of open fractures, degree of comminution (Winquist), associated injuries, knee symptoms and range of motion at follow-up, date of fracture union, and occurrence of complications or secondary procedures.

Results: Eighty-nine femoral fractures were treated with antegrade or retrograde reamed femoral nailing between February 1, 1998 and February 1, 1999 at a Level 1 trauma center. Forty-one fractures were treated with retrograde nailing and thiry-eight fractures were treated with antegrade nailing. One patient died in the early post-operative period in each group leaving 40 retrograde and 37 antegrade fractures available for follow-up. Currently 5 fractures in Group A and 5 fractures in Group R have insufficient follow-up and are under continued care. The average age in Group A was 27 and in Group R was 33. Table 1 displays the fracture characteristics for each group. Table 2 shows the number of nails used for each diameter.

Table 1- Fracture Characteristics

	Winquist					Location					Gustillo Grade			Ipsilateral Knee Inj
Technique	1	2	3	4	SG	ST	IS	IF	SC	SG	1	2	3A	IC	P	K	TP
Antegrade	16	6	7	8	1	11	21	5	0	1	2	3	2	1	1	0	1
Retrograde	19	6	10	4	2	2	23	13	1	2	3	1	0	1	4	0	1

(SG-segmental; ST-subtrochanteric; IS-Isthmal; IF-Infraisthmal; SC-Supracondylar; IC-intracondylar Fx; P-Patellar Fx; K-Knee ligament injury, TP-Tibial Plateau Fx)

Table 2- Nail Diameters

Technique	10mm	11mm	12mm
Antegrade	8	16	14
Retrograde	21	11	9

The average operative time was 79 minutes for Group A and 72 minutes for Group R. The average blood loss was 293 ml for Group A and 178 ml for Group R. The average time to union was 15.2 weeks in Group A and 18.3 weeks for Group R. Statistical analysis displayed a significant difference between the 2 groups only in the amount of blood loss (p<0.003). All other variables were not of statistical significance. Thirty-three of thirty-eight fractures in Group A had follow-up of greater than 180 days and the other 5 are under continued care. Thirty-two of the thirty-three (97%) healed in less than 180 days from injury. The one fracture that developed a delayed union (>180 days) united with a 1-cm leg-length discrepancy 60 days followg dynamization. Thirty-five of the forty fractures in Group R had follow-up of > 180 days and five fractures with < 180 days follow-up are under continued care. Thirty-four of thirty-five patients (97%) healed in less than 180 days. One patient with a delayed union has been dynamized, but has not united to date and is being followed. No fracture has required an exchange nailing or bone grafting to obtain union to date.

One patient with a shotgun wound and extensive muscle damage in Group A and two patients with patella fractures in Group R had significant loss of knee range of motion (<120^o flex or >5^o loss of extension). Three patients had failure of the distal locking bolts in the Group A (8%) and one patient had failure of the distal locking bolts in Group R (2%). The incidence of knee, hip, and thigh pain at last follow-up were similar in the 2 Groups (Table 3). Eight patients in Group R complained of pain over the distal locking bolts at follow-up (20%) and three required removal of the distal locking bolts to relieve this symptom (7.5%). Two patients in Group A (5%) complained of pain over the distal locking bolts and one required removal (3%).

Table 3-Outcomes

Technique	Union Weeks	Dynamize	Failed DS	Knee Pain	Hip Pain	Thigh Pain	Pain DS	Pain DS R/M	Union Rate
Antegrade	15.2	1	3	6	2	2	2	1	97%
Retrograde	18.3	1	1	7	1	3	8	3	97%

DS-Distal Screws; R/M-Removal

Discussion and Conclusions: Retrograde femoral intramedullary nailing has become a useful technique in the treatment of femoral shaft fractures. Previously two studies done by the authors showed dynamization rates of 8% and 18% with the use of ten-millimeter implants. In this study only 2% (1 patient) required dynamization with the employment of larger diameter canal-sized nails. The union rates with the ten-millimeter retrograde nails were slightly less than those with the ten-millimeter antegrade nails, and more secondary procedures were necessary. This study using canal-sized implants shows equal union rates of 97% in both the antegrade and retrograde groups. These larger diameter implants have yielded a better union rate with fewer secondary procedures emphasizing the fact that a match of the canal and nail diameter is important in retrograde nailing and leads to excellent results comparable to antegrade nailing.