Session V - Femur

A Prospective Comparison of Antegrade and Retrograde Femoral Intramedullary Nailing

Robert F. Ostrum, MD; Animesh Agarwal, MD; Ronald Lakatos, MD; Attila Poka, MD, Grant Medical Center, Columbus, OH

Purpose: Antegrade intramedullary nailing is the gold standard for treatment of diaphyseal femoral fractures. Recently, however, many orthopaedic traumatologists have utilized the retrograde technique, citing its advantages in the multiply injured patient and its technical ease. Opponents argue that violating the knee joint is unwarranted and will lead to problems with pain and loss of motion. The purpose of this study was to prospectively and critically examine a consecutive series of femur fractures treated with either antegrade or retrograde intramedullary nailing.

Methods: All patients with femoral shaft fractures from the lesser trochanter to the supracondylar femur, OTA types 32 and 33, were treated with a reamed intramedullary nail. The inception cohort had a ten millimeter cannulated antegrade (Synthes, Paoli, PA; Group A) or a retrograde titanium femoral nail (Biomet, Warsaw, IN; Group R) inserted. Ninety-two patients with one hundred fractures were treated in a prospective, consecutive series. Nails were locked according to stability, with all having proximal and distal locking screws. The following data were collected for all patients: demographics, Body Mass Index (BMI), operative time, blood loss, nail characteristics, femoral canal size, degree of comminution (Winquist), open grade (Gustillo), ISS, associated injuries, knee exam, time to union, secondary procedures, and complications.

Results: One hundred femoral shaft fractures were treated with antegrade or retrograde intramedullary nailing from January 1, 1997 to January 31, 1998 at a Level I trauma center. Nine were isolated femur fractures, and eight were bilateral. The overall average ISS was 16.6. Fifty-four fractures (seven bilateral) were treated with a retrograde nail and forty-six (one bilateral) with an antegrade nail. Differences in the demographics for the two groups were not statistically significant (NSS). The average age for group A was 26.6 years and for group R was 29.4 years. The average BMI for group A and R were 24.6 and 26.4, respectively. Table 1 shows the fracture characteristics. There were more Winquist 2-4 fractures, distal 1/3 femur fractures, and ipsilateral knee pathology in the retrograde group.

Table 1: Fracture Demographics

	Winquist					Location					Gustillo Grade				Ipsilateral Knee Inj
Technique	0	1	2	3	4	ST	IS	IN	SC	Seg	1	2	3A	3B	IC	Pa	KD	T-F
Antegrade	2	23	6	5	10	4	23	10	0	9	5	3	1	1	0	0	1	2
Retrograde	2	14	18	6	14	4	16	18	3	12	3	6	4	1	4	3	1	11

(ST-subtroch; IS-isthmus; IN-infraisthmal; SC-supracondylar; Seg-segmental; IC-intercondylar fx; Pa-patella fx; KD-knee dislocation; T/F-tibia fx/floating knee)

Nails were undersized equally in both groups, and statistical analysis indicated that undersizing of the retrograde nail had a significant effect on healing (p<0.05). A comparison of the operative times and blood loss of the two groups did not indicate significant differences. Follow-up knee evaluation revealed that 63.6% of patients in group A had full knee motion compared to 72.3% of group R (NSS). Group A had a quicker return of knee ROM (8.7 vs. 14.6 wks;p<0.05) and resolution of knee effusion (3.7 vs. 6.1 wks) than group R. There were no infections or septic joints in any patients.

Two patients died in the early post-injury period, twelve were lost to follow-up, and ten were done recently. Table 2 shows the outcome results for the remaining seventy-six fractures (Group A=31; Group R=45) with follow-up from six weeks to 51.4 weeks (mean 19.7 wks). Forty of forty-five (89%) fractures in group R healed at a mean of 15.9 weeks, whereas all thirty-one (100%) healed in the antegrade group at a mean of 14 weeks (NSS). Exchange nailing was done for one bent retrograde nail and one subtrochanteric antegrade nonunion. The retrograde group underwent more dynamizations (18% vs. 6%; NSS), and had more symptomatic distal locking screws (33% vs. 10%; NSS) of which only four required removal. Three of the eight patients that underwent dynamization in the retrograde group healed at an average of 79 days after the procedure (27-105 days); the two in the antegrade group healed in 36.5 days (29-44). Four group R patients underwent dynamization recently (6-59 days) and have shown progression of healing. Knee pain was equal in both groups, but hip and thigh pain predominated, group A. A trendelenberg gait was initially present in all antegrade patients and persistent in one. ANOVA statistical analysis found that there were no significant effects of Winquist or Gustillo grade classification on fracture healing in either group, but location did have an effect. The analysis indicated that a subtrochanteric fracture took longer to heal than any other fracture (Group R 30.9 wks p<0.0001; Group A 24.6 wks NSS). The fractures with secondary subtrochanteric extension healed in a timely fashion.

Table 2: Outcome Results

Technique	Union Weeks	Dynamize	Exchange Nail	Knee Pain	Hip Pain	Thigh Pain	Symptom DS	Sx DS Rem
Antegrade	14.0	2	1	7	6	8	3	3
Retrograde	15.9	8	1	8	1	3	15	4

(Legend: Symptom DS-Symptomatic Distal Screws; Sx DS Rem-Symptomatic Distal Screw Removal)

Discussion and Conclusion: This prospective consecutive series of patients indicates that there were no statistically significant differences in the outcome parameters between antegrade and retrograde nailing. The retrograde technique is advantageous in many settings: bilateral injuries, obese patients, pregnant patients, and in multiple trauma - ipsilateral pelvic, acetabular, femoral neck or tibia fractures. Retrograde nailing achieved an excellent union rate with no associated knee complications. The present study indicated an equal incidence of knee pain in both groups. The delay in the resolution of knee effusions and in regaining knee motion in the retrograde group was thought to be related to the large number of associated knee pathology and not the technique. Antegrade patients had different problems: Trendelenberg gait, weak hip abductors, hip and thigh pain. The antegrade group had 100% union with secondary procedures. The retrograde group had 89% union with secondary procedures; this was not a significant difference. Four retrograde patients have not had adequate time to heal post-dynamization, but radiographs have shown progression of healing. The time to union in both groups was the same. The increase in dynamizations in group R may be attributed to the standard utilization of ten millimeter nails, which resulted in a greater nail to canal size mismatch in the retrograde group. This undersizing was also found to have a significant effect of prolonging the time to union in the retrograde group only. This suggests that the biomechanics of the retrograde nail may in fact be different than those of the antegrade nail. Further investigation is needed to assess these issues.