The goal of this study was to compare the results of proximal femoral nail antirotation (PFNA; Synthes, Oberdorf, Switzerland) fixation with those of Gamma nail 3 (GN-3; Stryker, Mahwah, New Jersey) fixation for unstable proximal femoral fractures. A total of 136 unstable trochanteric fractures were divided into 2 treatment groups: 66 patients were treated with the PFNA and 70 were treated with the GN-3. The 2 groups were comparable with regard to demographic variables. Patients treated with the PFNA experienced less intraoperative blood loss (P=.007). Three femoral shaft fractures (2 PFNA, 1 GN-3) were observed intraoperatively; all were minor splits in the cortex at the tip of the nail and were treated successfully with delayed full weight bearing.
Follow-up occurred at 1, 3, 6, and 12 months postoperatively and yearly thereafter. Reduction of the fracture was considered good in 74 patients (35 PFNA, 39 GN-3) and the position of the implant was considered ideal in 103 (48 PFNA, 55 GN-3) on postoperative radiographs. The 2 groups were similar with regard to postoperative complications, and no case of cutout or nonunion was noted during the follow-up period. At last follow-up, there was no difference in the functional outcome. Shortening of the femoral shaft was 5.30±0.36 mm in PFNA group and 5.49±0.39 mm in GN-3 group (P=.73). There was no difference in clinical outcome between the PFNA and GN-3 groups, although the PFNA shows some advantages over the GN-3. We consider these 2 methods to be useful in the treatment of unstable proximal femoral fractures.
The best treatment of unstable proximal femoral fractures remains controversial. Intramedullary devices have shown superior biomechanical advantages over extramedullary implants and are recommended for such fractures.1-4 Earlier intramedullary devices like the standard Gamma nail showed higher rates of implant-related complications such as femoral shaft fracture (17%),5,6 fixation failure (7%),7 and distal locking complications (10%)6 requiring reoperation. Despite these complications, the Gamma nail—particularly the latest evolution, the Gamma nail 3 (GN-3; Stryker, Mahwah, New Jersey)—is still widely used for the treatment of these fractures.
The published data so far confirm the newer proximal femoral nail to be a reliable implant with comparable results for the unstable proximal fracture.2,3,8 However, various authors have reported screw cutout of the femoral head and a higher rate of intraoperative difficulties.2,9,10
In 2004, the proximal femoral nail antirotation (PFNA; Synthes, Oberdorf, Switzerland) was developed by AO/ASIF (Davos, Switzerland) as an alternative to the proximal femoral nail. It has a small distal shaft diameter, resulting in less stress concentration of the tip. The greatest change is a helical neck blade instead of 2 proximal screws. The PFNA blade claims to compact the cancellous bone to provide increased stability and has been biomechanically proven to retard rotation and varus collapse.11 Since its introduction, several clinical studies have shown good results with few intraoperative problems and a low complication rate.12,13
The question arises whether new intramedullary implants like the PFNA and the GN-3 produce different results. We therefore initiated a randomized, prospective trial comparing the PFNA and the GN-3 for differences in complications and outcome.
Materials and Methods
Between January 2006 and August 2008, all patients with unstable proximal femoral fractures in our hospital were considered for the study. Inclusion criteria were a radiological diagnosis of an unstable proximal femoral fracture, AO/ASIF classification of 31A2 and 31A3, age older than 60 years, American Society of Anesthesiologists (ASA) score I to IV, and signed informed consent by the patient (or relatives in cases of illiteracy or dementia). Exclusion criteria were pathologic fractures, inability to work before injury, and a severe concomitant medical condition (ASA V).
A total of 136 patients were included in the study and randomized into 2 treatment groups: PFNA (66) and GN-3 (70). No patient refused randomization, which was accomplished with the use of consecutive numbered and sealed envelopes based on a computer-generated list. Sealed envelopes were opened before the surgeon performed an operation.
Background parameters, ASA risk score, and preadmission mobility were recorded. Mobility was assessed using the Parker and Palmer14 mobility score.
All operations were performed by surgeons who had experience with at least 5 procedures using the PFNA and the GN-3 (Y.X., H.Y.). Each patient was given antibiotics with ceftriaxone preoperatively. The method of anesthesia was either general or spinal. The anesthetic was given by a specialist registrar anesthetist. Patients underwent surgery on a traction table in the supine position, and, if possible, closed reduction was performed under image-intensifier control.
Surgery was performed according to a standard protocol for either PFNA or GN-3, which are recommended by the manufacturer and have been described in earlier studies (Figures 1, 2).12,13,15 The PNFA used in the study was a solid titanium nail of 170 or 240 mm in length and 10 or 11 mm in diameter with a mediolateral curvature of 6°, which was inserted without reaming of the medullary canal. The special helical blade was inserted into the femoral neck without drilling. The PFNA may be distally locked either dynamically or statically. The GN-3 used was a 170-mm cannulated steel nail with a lower mediolateral curvature (4°) and a diameter of 11 mm. The femur was reamed 2 mm larger than the proximal and distal diameters of the nail, and insertion was performed manually without hammering. There is 1 distal locking screw for antirotation. The neck shaft angle of the 2 devices was 130°. The PFNA and the GN-3 were inserted using the percutaneous technique.
Operation time, fluoroscopy time, blood loss, and any intraoperative complications were recorded. Postoperatively, all patients had suction drains for 24 to 48 hours and were given prophylactic antibiotics for 3 to 5 days. Patients received a blood transfusion if their hemoglobin level was <8 g/dl or if they became symptomatic with a hemoglobin level between 8 and 10 g/dl. All patients were encouraged to move hip, knee, and ankle joints the first postoperative day under the guidance of the surgeon. The continuous passive motion machine was used twice a day when the drainage tube was removed. All patients were encouraged to walk partially weight bearing, starting as soon as possible postoperatively, assisted by a surgeon.
Standard plain anteroposterior (AP) and lateral radiographs were obtained on the first postoperative day, or during the hospitalization period. The quality of reduction of the fracture was classified as good if alignment was normal, acceptable (5°-10° varus/valgus and/or anteversion/retroversion), or poor (>10° varus/valgus and/or anteversion/retroversion). The ideal position of the blade or screw was defined as being central or inferior on the AP radiograph and central on the lateral radiograph.2
Follow-up occurred at 1, 3, 6, and 12 months postoperatively and yearly thereafter. At each follow-up, we recorded the hip range of motion (ROM), pain about the hip and thigh, and walking ability score. Plain AP and lateral radiographs were obtained at each follow-up, and any changes in implant position, complications, or fixation failures were recorded. Shortening of the femur was measured on the last radiograph.
Statistical analysis was performed using SPSS 10.0 (SPSS Inc, Chicago, Illinois). Student t test was used to compare study outcome measures with parametric means. Chi-square test and Fisher’s exact test were used to compare nonparametric means. The level of statistical significance was set at a two-sided P value of .05.
The 2 treatment groups were comparable in age, sex, ASA score, injury mechanism, and mobility before injury. Most of the fractures were caused by a fall during walking. The other causes were a fall from height or a traffic accident. The fracture patterns were comparable in both groups with application of the AO/ASIF classification (Table 1).
The method of anesthesia (general or spinal) did not differ between the groups. Open reduction was performed in 33 patients (14 PFNA, 19 GN-3). The mean intraoperative blood loss differed significantly: 217.4±13.6 mL in the PFNA group compared with 272.7±14.8 mL in the GN-3 group (P=.0071). However, patients receiving blood transfusions and the units of blood transfused did not differ significantly between the 2 groups. The mean operating time was 64.1±1.9 minutes in the PFNA group compared with 68.6±2.4 minutes in the GN-3 group (P=.1414). The fluoroscopy time was significantly longer in the GN-3 group (3.2±0.13 minutes) compared with the PFNA group (2.7±0.14 minutes) (P=.0083).
Fracture reduction was considered good in 74 patients (35 PFNA, 39 GN-3) and implant position was considered ideal in 89 (41 PFNA, 48 GN-3) on postoperative radiographs. There were no significant differences between the quality of reduction for both implant and fracture types (31-A2 and A3). Patients were discharged a mean 7.3 days postoperatively. The time of fracture healing was 9.65±2.19 weeks in the PFNA group compared with 10.21±2.83 weeks in the GN-3 group, and the difference was not significant (Table 2).
Intra- and postoperative complications are listed in Table 3. One case of femoral shaft fracture occurred in the GN-3 group and 3 in the PFNA group. The 4 femoral shaft fractures occurred either intraoperatively (3) or postoperatively (1). Those occurring intraoperatively were minor splits in the cortex at the tip of the nail and were treated with delayed full weight bearing for 6 to 8 weeks (Figure 3). These patients mobilized well without further problems at last follow-up. In the PFNA group, 1 patient sustained a femoral shaft fracture 1 month postoperatively because of a fall and was treated with an osteosynthesis plate. The proximal screws or blades migrated laterally in 3 GN-3 patients and 6 PFNA patients, which were treated conservatively. There were no cases of nonunion or cutout in either group.
Both groups were similar with regard to general and local wound complications. There were 11 hematomas (5 PFNA, 6 GN-3) of the surgical wound, which resolved satisfactorily in all cases. Evidence of superficial infection was found in 2 patients in the PFNA group, compared with 1 in the GN-3 group. No deep infection was noted during the follow-up period. Nine cases (5 PFNA, 4 GN-3) of postoperative chest infection required treatment with antibiotics.
At last follow-up, 93 of the initial 136 patients were eligible for an outcome analysis (46 PFNA, 47 GN-3). Of the 43 not eligible for analysis, 3 died in the immediate postoperative period and another 12 died before last follow-up. Twenty-one patients did not attend final review because they were too ill. Seven patients were lost to follow-up because they moved. Mean follow-up was 17.68±4.05 months (range, 12-27 months). Mean femoral shaft shortening was 5.15 mm when measured on AP radiographs. At last follow-up, more patients reported hip and thigh pain in the PFNA group than in the GN-3 group, although the difference was not significant (P=.0649). Sixty-one patients (29 PFNA, 32 GN-3; P=.6089) recovered their preoperative weight bearing ability, and there was no significant difference between the 2 groups with regard to walking ability and range of hip flexion at last follow-up (Table 4).
Our results with these 2 implants in patients older than 60 years with unstable proximal femoral fractures showed no important differences in patient outcomes and complication rates.
Biomechanical examinations have shown that intramedullary devices may be superior to plating systems in unstable proximal femoral fractures.4 The basic designs of the PFNA and the GN-3 are similar in that the nail has an anatomic lateral bend, an anatomic head-neck angle of 130°, and distal diameters from 10 to 11 mm. The major difference between these 2 implant designs is the manner in which the femoral head is stabilized. The GN-3 uses a sliding hip screw inserted with the conventional drill and tap method, while the PFNA uses a helical blade inserted by impaction without predrilling and tapping.
Strauss et al11 reported that fixation of the femoral head with a helical blade was biomechanical superior to fixation with a standard sliding hip screw. A similar biomechanical advantage of the blade design over the conventional lag screw was demonstrated by Sommers et al,16 in a comparison of cutout resistance provided by implants used for trochanteric fracture fixation. However, no cutout was noted in any groups in our trial. Schipper et al2 reported that the cutout generally appeared to result from poor position of the proximal screw in femoral head, rather than being implant-related. The importance of the proper position of the screw has been emphasized before.
Fluoroscopy time and intraoperative blood loss were less in the PFNA group, and we attribute this to the fact that reaming is not necessary for the placement of this nail.12,13 However, the number of patients transfused and the units of blood transfused between the 2 groups were similar. The invisible bleeding during placement of the PFNA and blood loss at the fracture itself pre- and postoperatively may play a role. We consider that less blood loss was not an advantage over GN-3.
Fracture of the femoral shaft at the tip of the nail is a known complication associated with the use of an intramedullary nail in the treatment of proximal femoral fractures.1,2,5-7 Results from other studies show higher numbers of femoral shaft fractures, up to 17%.5,6 In our study, 3 femoral shaft fractures occurred intraoperatively and 1 occurred 1 month postoperatively. The intraoperative fractures were minor cortical splits at the tip of the nail and were treated conservatively with delayed full weight bearing. After 6 to 8 weeks, the patients were allowed full weight bearing. Moreover, the intraoperative fractures were all noted in the early stage of the study, and we attributed this complication to our learning curve. The 1 postoperative femoral shaft fracture in the PFNA group, which was caused by a fall, was treated with an osteosynthesis plate. These fractures healed well and did not impact patient mobility at last follow-up.
Lateral migration of the proximal screws or the helical blade was also a complication of these 2 implants.2,12,17 Nine cases (6 PFNA, 3 GN-3) of lateral migration were noted during the follow-up period without severe symptoms, and they did not impact the patients’ activities of daily living. We considered this complication to be caused by impaction of the fracture, because the anchorage of the helical blade or the lag screws in the femoral head was similar before and after migration. Although not significantly different, patients treated with a PFNA had a slightly higher rate of lateral migration. This may be explained in part by the lower friction coefficient of titanium (PFNA) than stainless steel (GN-3).2
Hip and thigh pain were common complications when treating this fracture with an intramedullary implant.2,15 More patients in the PFNA group reported thigh pain at last follow-up, although the difference was not significant. A reasonable explanation was the mismatch between the proximal end of the PFNA nail and the proximal femur in short, elderly patients. As the average height of the Chinese population is less than that of Europeans and Americans, the proximal femoral length is relatively shorter.18 The PFNA II has been developed for Asian patients and may avoid such complications.
Almost all fractures showed union within 3 months, and 59.5% of patients achieved the same or a minimally diminished pre-trauma Parker Mobility Score without any correlation to the implant used. This finding is comparable with the results of retrospective studies by Simmermacher et al12 and Mereddy et al,13 who also observed restoration of preoperative mobility in approximately 56% to 80% of the patients treated with the PFNA. Similarly, the use of the GN-3 seems to generate comparable results.2,15 These results demonstrate that approximately half the patients with unstable proximal femoral fractures return to their preoperative domestic status at the time of fracture healing, regardless of the treatment method used.
A common problem in previous studies, as in ours, is the high number of patients who withdraw.2 This is partially explained by the age of the patients. In our series, the 43 patients who did not attend last follow-up had either died or were too ill to attend. Since the drop-out rate is comparable between the 2 groups, there is no bias in the interpretation of the results when the 2 methods are compared.
The ideal implant for unstable femoral shaft fractures should be minimally invasive, allow full weight bearing postoperatively, and have a low complication rate. The results of our study show that the newly developed PFNA is as good as the GN-3, with comparable complications. These 2 methods are useful in the treatment of unstable proximal femoral fractures.
- Hardy DC, Descamps PY, Krallis P, et al. Use of an intramedullary hip-screw compared with a compression hip-screw with a plate for intertrochanteric femoral fractures. A prospective, randomized study of one hundred patients. J Bone Joint Surg Am. 1998; 80(5):618-630.
- Schipper IB, Steyerberg EW, Castelein RM, et al. Treatment of unstable trochanteric fractures. Randomised comparison of the gamma nail and the proximal femoral. J Bone Joint Surg Br. 2004; 86(1):86-94.
- Menezes DF, Gamulin A, Noesberger B. Is the proximal femoral nail a suitable implant for treatment of all trochanteric fractures? Clin Orthop Relat Res. 2005; (439):221-227.
- Curtis MJ, Jinnah RH, Wilson V, Cunningham BW. Proximal femoral fractures: a biomechanical study to compare intramedullary and extramedullary fixation. Injury. 1994; 25(2):99-104.
- Kukla C, Heinz T, Gaebler C, Heinze G, Vécsei V. The standard Gamma nail: a critical analysis of 1,000 cases. J Trauma. 2001; 51(1):77-83.
- Leung KS, So WS, Shen WY, Hui PW. Gamma nails and dynamic hip screws for peritrochanteric fractures. A randomised prospective study in elderly patients. J Bone Joint Surg Br. 1992; 74(3):345-351.
- Ahrengart L, Törnkvist H, Fornander P, et al. A randomized study of the compression hip screw and Gamma nail in 426 fractures. Clin Orthop Relat Res. 2002; (401):209-222.
- Al-yassari G, Langstaff RJ, Jones JW, Al-Lami M. The AO/ASIF proximal femoral nail (PFN) for the treatment of unstable trochanteric femoral fracture. Injury. 2002; 33(5):395-399.
- Simmermacher RK, Bosch AM, Van der Werken C. The AO/ASIF-proximal femoral nail (PFN): a new device for the treatment of unstable proximal femoral fractures. Injury. 1999; 30(5):327-332.
- Ekström W, Karlsson-Thur C, Larsson S, Ragnarsson B, Alberts KA. Functional outcome in treatment of unstable trochanteric and subtrochanteric fractures with the proximal femoral nail and the Medoff sliding plate. J Orthop Trauma. 2007; 21(1):18-25.
- Strauss E, Frank J, Lee J, Kummer FJ, Tejwani N. Helical blade versus sliding hip screw for treatment of unstable intertrochanteric hip fractures: a biomechanical evaluation. Injury. 2006; 37(10):984-989.
- Simmermacher RK, Ljungqvist J, Bail H, et al. The new proximal femoral nail antirotation (PFNA) in daily practice: results of a multicentre clinical study. Injury. 2008; 39(8):932-939.
- Mereddy P, Kamath S, Ramakrishnan M, Malik H, Donnachie N. The AO/ASIF proximal femoral nail antirotation (PFNA): a new design for the treatment of unstable proximal femoral fractures. Injury. 2009; 40(4):428-432.
- Parker MJ, Palmer CR. A new mobility score for predicting mortality after hip fracture. J Bone Joint Surg Br. 1993; 75(5):797-798.
- Utrilla AL, Reig JS, Muñoz FM, Tufanisco CB. Trochanteric gamma nail and compression hip screw for trochanteric fractures: a randomized, prospective, comparative study in 210 elderly patients with a new design of the gamma nail. J Orthop Trauma. 2005; 19(4):229-233.
- Sommers MB, Roth C, Hall H, et al. A laboratory model to evaluate cutout resistance of implants for pertrochanteric fracture fixation. J Orthop Trauma. 2004; 18(6):361-368.
- Herrera A, Domingo LJ, Calvo A, Martínez A, Cuenca J. A comparative study of trochanteric fractures treated with the Gamma nail or the proximal femoral nail. Int Orthop. 2002; 26(6):365-369.
- Leung KS, Procter P, Robioneck B, Behrens K. Geometric mismatch of the Gamma nail to the Chinese femur. Clin Orthop Relat Res. 1996; (323):42-48.
Drs Xu, Geng, Yang, Wang, and Zhu are from the Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, China.
Drs Xu, Geng, Yang, Wang, and Zhu have no relevant financial relationships to disclose.
Correspondence should be addressed to: Yaozeng Xu, MD, PhD, Department of Orthopedics, The First Affiliated Hospital of Soochow University, 188, Shizi Rd, Suzhou, 215006, China (firstname.lastname@example.org).