The proximal femoral nail antirotation system was introduced by the
Arbeitsgemeinschaft fur Osteosynthesfragen/Association for the Study of
Internal Fixation (AO/ASIF) in 2003 and is suitable for treating unstable
trochanteric fractures. However, proximal femoral nail antirotation was
designed according to the geometric proportions of the White population, and it
is known that important differences exist between Asians and Americans with
regard to femoral geometry. Reports of serious postoperative complications also
exist when used for the elderly Asian population. Therefore, geometrical
mismatch between proximal femoral nail antirotation and the femora of Asians
has led the AO/ASIF to design a new proximal femoral nail antirotation for Asia
with adapted sizes and geometry. This article reports early clinical results of
using proximal femoral nail antirotation for Asians in 84 consecutive patients
to stabilize unstable trochanteric fractures (AO classification, 31.A2 and A3).
Patients were followed up for an average 8 months (range, 4-11 months).
Intraoperative and postoperative complications, surgical details, and outcome
measurements were evaluated. Fractures were treated by closed reduction and
intramedullary fixation. The proximal femoral nail antirotation Asia position
was ideal in 80 cases (95%). No patients showed complication related to the
mismatch between the nail and femora. The mean time to bone healing was 14
weeks. Functionally, 90% of the patients regained pretrauma mobility. According
to the Harris hip scoring system, 63 patients (78%) had an excellent or good
outcome. The new proximal femoral nail antirotation Asia yields better results
in the treatment of unstable trochanteric fractures in elderly patients by
closely matching Asian femoral anatomy and thereby reducing complications
related to the implants.
Unstable trochanteric fractures are common in elderly patients and
their treatment continues to be a challenge for orthopedic surgeons. The
dynamic hip screw is an adequate implant that has been available for years for
31.A1 fractures (Arbeitsgemeinschaft fur Osteosynthesefragen/Association for
the Study of Internal Fixation [AO/ASIF] classification).1,2 For the
unstable A2 and A3 fractures, intramedullary stabilization including the Gamma
nail, proximal femoral nail, and proximal femoral nail antirotation, has become
a standard procedure over the past decade.3-5 The proximal femoral
nail antirotation system was introduced by the AO/ASIF in 2003 and is the most
suitable for treating unstable trochanteric fractures.5-8 However,
proximal femoral nail antirotation was designed according to the geometric
proportions of Caucasians, and it is known that there are important differences
between Asians and Americans with regard to the femoral
geometry.9,10 For example, Chinese women have shorter femoral necks,
smaller femoral neck angles, and increased anterior bowing of the shaft than
those in white Americans.11,12 A study reported that the proximal
end of the nail did not match the specific anatomy of some patients of short
stature when used for treating an elderly Chinese population.5 In
addition, reports of postoperative complications have arisen.13,14
Therefore, further modifications of proximal femoral nail antirotation are
necessary for the elderly Asian population.
According to geometric proportions of Asians, the AO/ASIF designed the
proximal femoral nail antirotation Asia with adapted sizes and geometry. The
current study was undertaken to evaluate the early clinical outcomes of
unstable trochanteric fractures that were treated using this new design.
Materials and Methods
The study included patients older than 65 years of age who had a
recent traumatic unstable trochanteric fracture that was treated using proximal
femoral nail antirotation Asia within 7 days and were able to attend the
planned follow-up. Patients with previous implants in the fractured hip or
femur and those who were bedridden or wheelchair-bound before injury were
excluded. Informed consent was obtained from the patients or their guardians.
The modified nail of the proximal femoral nail antirotation Asia
(Synthes GmbH, Oberdorf, Switzerland) has a proximal lateral flat surface, a
mediolateral angle of 5°, and a proximal diameter of 16.5 mm to suit the
anatomical characteristics of Asians. The blade is available in lengths of 75
to 120 mm in steps of 5 mm (Table 1, Figure 1). Additionally, the proximal
femoral nail antirotation Asia, like the proximal femoral nail antirotation, is
available in 4 sizes (standard, small, extra small, and long) with 4 different
distal diameters ranging from 9 to 12 mm. The long proximal femoral nail
antirotation Asia (300 and 340 mm) is available in 2 distal diameters of 9 and
|Figure 1: The proximal femoral nail
antirotation Asia design.
The AO classification system15 was adopted to classify the
fractures and the American Society of Anesthesiologists (ASA) scale16
was used to evaluate comorbidity.
All fractures were treated by closed reduction with proximal
femoral nail antirotation Asia under C-arm fluoroscopy control. Using a
fracture table, the fractured hip was placed in a slightly adducted position to
facilitate the insertion of the nail. All operations were performed by the same
group of experienced surgeons (C.L., Y.F., L.L.). The surgical procedure was
the same as that used for the standard proximal femoral nail antirotation, in
the manufacturers instructions. The operative time, blood loss during
surgery, overall fluoroscopy time, amount of transfused blood, duration of
hospitalization, surgical complications, and assessment of nail handling for
proximal femoral nail antirotation Asia were compared with those of proximal
femoral nail antirotation.
In all cases, antithrombotic prophylaxis was administered using
low-molecular-weight heparin for 3-5 days, and antibiotic prophylaxis was
administered within 1 day after the operation. Rehabilitation was important;
patients were mobilized on the first postoperative day, and partial weight
bearing was encouraged with the aid of a walker or crutches on the following
Radiographs of the affected hip were obtained in the
anteroposterior (AP) and medial-lateral planes to assess postoperative fracture
reduction. The quality of fracture reduction was graded as good, acceptable
(5-10° varus/valgus and/or anteversion/retroversion), or poor (>10°
varus/valgus and/or anteversion/retroversion).17 The position of the
proximal femoral nail antirotation was graded as good if the blade was placed
into the lower half of the neck on the AP view and centrally on a lateral view
and if the nail did not protrude outside the greater trochanter.
Follow-up evaluations, which included a clinical and radiographic
assessment, were performed at 4, 12, 24, and 52 weeks. The clinical results
were assessed using the Harris hip score.18 Harris hip scores were
categorized as excellent (90-100 points), good (80-89 points), fair (70-79
points), or poor (<69 points). Radiographs of the affected hip were
obtained in the AP and mediolateral planes at each follow-up visit, and any
changes in the position of the implant and the extent of the fracture union
were noted. Fractures were judged to be healed radiographically if the bridging
callus was evident on 3 to 4 cortices, as noted on 2 views.19
From November 2009 to October 2010, eighty-four consecutive
patients with unstable trochanteric fractures were included in this study.
Preoperative patient data are shown in Table 2. There were 60 female and 24
male patients with a mean age of 79.5 years (range, 65-92 years). The majority
of the fractures resulted from a fall at home. According to the AO
classification,15 fifty-seven fractures were classified as 31.A2 and
27 fractures as 31.A3. In addition, 24 patients were classified as ASA 1,
thirty-nine patients were classified as ASA 2, fifteen patients were classified
as ASA 3, and 6 patients were classified as ASA 4, reflecting significant
comorbidity ranging from malignancies to cardiac morbidity.
All fractures were successfully treated by closed reduction. The
mean duration of surgery (skin to skin) was 48 minutes for A2 fractures and 61
min for A3 fractures. C-arm fluoroscopy control required a mean time of 113
seconds for fixing A2 fractures and 152 seconds for fixing A3 fractures. Mean
blood loss was 50 mL in A2 fractures and 150 mL in A3 fractures. Twenty-four
patients required blood transfusions with an average volume of 400 mL. The mean
duration of hospital stay was 7 days. Ten patients did not require reaming, as
shown in Table 3. Postoperative radiographs showed a good or acceptable
fracture reduction in 78 cases (93%), an ideal implant position in 80 cases
(95%), and a tip-apex distance of 10 to 20 mm in 50% of patients (Table 4).
Of the proximal femoral nail antirotation Asia standard sizes,
the 90-mm and 95-mm blade sizes and 170-mm nail length were the most frequently
used. All distal locking procedures were performed using static or dynamic
instruments by using one 4.9-mm screw. Insertion of the nail was perceived to
be easy. The proximal end of the nail and proximal femur matched well in most
patients (Figure 2).
|Figure 2: An
85-year-old woman sustained an isolated and closed Arbeitgemeinschaft
Osteosynthesefragen classifi cation 31.A2 fracture at the left side after a
fall at home. Preoperative AP radiograph showing the displaced
intertrochanteric fracture (A). Postoperative radiograph after closed reduction
and internal fixation using proximal femoral nail antirotation Asia (B).
Follow-up AP radiograph of the left hip at 3 months postoperatively showing the
united fracture with the proximal femoral nail antirotation in situ (C).
Abbreviation: L, left.
At most recent follow-up, 2 patients died within 4 months due to
causes unrelated to the implant, and 4 patients could no longer be contacted or
refused further participation. The remaining 78 patients were evaluated.
Ninety-eight percent of the fractures united with a good component position,
and the average time to bone healing was 14 weeks (range, 12-24 weeks). None of
the patients had deep infection or failures or breakages due to implant
fatigue. Mechanical failures such as bending or breaking of the implant or
intraoperative or postoperative fractures were not noted; screw cut-outs were
also not observed. None of the patients developed thigh pain or mismatch of the
proximal end of the nail or required reoperation. Ninety percent of the
patients regained their preinjury mobility and could take care of themselves.
The Harris hip score results were as follows: 24, excellent; 37, good; 13,
fair; and 4, poor. In all, 61 patients (78%) showed an excellent or good
outcome. The mean Harris hip score was 85 points (range, 52-95 points).
A long debate has been ongoing concerning the preferred implant
for stabilization of unstable trochanteric fractures. For operative treatment
of this kind of fracture, 2 options exist: extramedullary or intramedullary
stabilization. Because of the biomechanical advantage and minimal invasion,
intramedullary devices such as the Gamma nail, proximal femoral nail, and
proximal femoral nail antirotation are preferred in elderly
patients.3,20,21 To improve the rotational and angular stability
using a single element, the AO/ASIF group modified the proximal femoral nail to
the proximal femoral nail antirotation in 2003. The compaction of cancellous
bone is a unique property of the proximal femoral nail antirotation blade, and
it has been biomechanically proven to have a better purchase in the
osteoporotic bone.22 Unstable trochanteric fractures have been
successfully treated using proximal femoral nail
antirotation.5-7,13,14 However, when proximal femoral nail
antirotation is used in the Asian population, suitable implants are not always
available and geometric mismatch between the proximal end of the nail and
proximal femur are generally encountered in elderly patients of short stature.
To improve the design of the nail, the AO/ASIF designed the new proximal
femoral nail antirotation Asia, on the basis of an anthropometric study.
The standard proximal femoral nail antirotation nail has a
mediolateral angle of 6° and a proximal diameter of 17 mm. To insert the
nail, a much larger femoral canal needs to be prepared to accommodate the nail
of the given diameter.23 This means that a considerable amount of
cortical bone has to be reamed, thus weakening the osteoporotic bone in most
patients. Friedl et al24 suggested that the necessary overreaming of
the shaft weakens the entire shaft,25 and that reaming of the
medulla can lead to increased blood loss. In addition, this geometric mismatch
between the proximal end of the nail and proximal femur is the most probable
cause of the intraoperative complications of jamming and fracturing of the
lateral cortex. Based on the results of the anthropometric study, the modified
nail was designed to have a mediolateral angle of 5° and a proximal
diameter of 16.5 mm. Additionally, the proximal lateral surface was made flat
to facilitate insertion and to lower the pressure on the lateral cortex. The
modified nail, therefore, has a considerably better anatomic fit. In this
study, nearly 70% of the fractures could be fixed using lesser degrees of
reaming or with no reaming. The decrease in the mediolateral curvature and the
proximal diameter together with a proximal lateral flat surface facilitated
insertion and lowered the stress on the anterior and medial cortices. This
effectively decreases the hoop stress inside the femoral shaft and may have
contributed to a significant decrease in intraoperative and postoperative
diaphyseal fractures.26 In our consecutive patients, no diaphyseal
fractures related to the nail were found. All of the fractures healed within 4
months. Postoperative radiographs showed a good or acceptable reduction in 78
cases (93%) and an ideal implant position in 80 cases (95%).
With the new proximal femoral nail antirotation Asia, the operative
technique could be improved to facilitate implantation. Operative time, blood
loss, and fluoroscopy time were greatly reduced compared with those of the
standard proximal femoral nail antirotation and other reported
Thigh pain and discomfort have been reported to occur occasionally
when the standard proximal femoral nail antirotation is used; a study reported
that 11 out of 87 patients who underwent treatment with proximal femoral nail
antirotation experienced tenderness in the affected hip after the
operation.5 The main reason for this tenderness is a mismatch
between the femoral component and the geometry of the proximal femur, which
affects the insertion of the nail and causes an excessive protrusion of the
nail outside the greater trochanter, resulting in unnecessary irritation around
the hip (Figure 3). Previously, the position of the blade was the only standard
used to evaluate proximal femoral nail antirotation position.8,21 In
this study, the position of the end of the nail was used as an additional
standard besides the blade. As a result, in 95% of patients, the proximal
femoral nail antirotation was in a good position, and thigh pain and discomfort
were not observed.
|Figure 3: A 90-year-old man (height, 155
cm; weight, 58 kg) underwent surgery using the smallest version of the standard
proximal femoral nail antirotation (length, 170 mm). The proximal end of the
nail is prominent (arrow).
The early results of the proximal femoral nail antirotation Asia were
satisfactory in most patients included in this study. The modification of the
proximal femoral nail antirotation provides an anatomic fit in the proximal
femur and contributes to decreased complications. However, the number of the
patients included in our study was small and the time of the follow-up was
short. A multicentric clinical study will be required for definitive
- Baumgaertner MR, Curtin SL, Lindskog DM. Intramedullary versus
extramedullary fixation for the treatment of intertrochanteric hip fractures.
Clin Orthop Relat Res. 1998; (348):87-94.
- Fritz T, Hiersemann K, Krieglstein C, Friedl W. Prospective
randomized comparison of gliding nail and gamma nail in the therapy of
trochanteric fractures. Arch Orthop Trauma Surg. 1999;
- Pelet S, Arlettaz Y, Chevalley F. Osteosynthesis of per- and
subtrochanteric fractures by blade plate versus gamma nail. A randomized
prospective study. Swiss Surg. 2001; 7(3):126-133.
- 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.
- Pu JS, Liu L, Wang GL, Fang Y, Yang TF. Results of the proximal
femoral nail anti-rotation (PFNA) in elderly Chinese patients [published online
ahead of print April 15, 2009]. Int Orthop. 2009; 33(5):1441-1444.
- Takigami I, Matsumoto K, Ohara A, et al. Treatment of trochanteric
fractures with the proximal femoral nail antirotation (PFNA) nail
systemreport of early results. Bull NYU Hosp Jt Dis. 2008;
- Simmermacher RK, Ljungqvist J, Bail H, et al. The new proximal
femoral nail antirotation (proximal femoral nail antirotation) in daily
practice: results of a multicentre clinical study [published online ahead of
print June 25, 2008]. Injury. 2008; 39(8):932-939.
- Mereddy P, Kamath S, Ramakrishnan M, Malik H, Donnachie N. The
AO/ASIF proximal femoral nail antirotation (proximal femoral nail
antirotation): a new design for the treatment of unstable proximal femoral
fractures [published online ahead of print February 20, 2009]. Injury.
- Nakamura T, Turner CH, Yoshikawa T, et al. Do variations in hip
geometry explain differences in hip fracture risk between Japanese and white
Americans? J Bone Miner Res. 1994; 9(7):1071-1076.
- Choi BY, Chae YM, Chung IH, Kang HS. Correlation between the
postmortem stature and the dried limb-bone lengths of Korean adult males.
Yonsei Med J. 1997; 38(2):79-85.
- Tang WM, Chiu KY, Kwan MF, Ng TP, Yau WP. Sagittal bowing of the
distal femur in Chinese patients who require total knee arthroplasty. J
Orthop Res. 2005; 23(1):41-45.
- Leung KS, Procter P, Robioneck B, Behrens K. Geometric mismatch of
the Gamma nail to the Chinese femur. Clin Orthop Relat Res. 1996;
- Hwang JH, Oh JK, Han SH, Shon WY, Oh CW. Mismatch between PFNa and
medullary canal causing difficulty in nailing of the pertrochanteric fractures
[published online ahead of print September 11, 2008]. Arch Orthop Trauma
Surg. 2008; 128(12):1443-1446.
- Brunner A, Jockel JA, Babst R. The proximal femoral nail
antirotation proximal femur nail in treatment of unstable proximal femur
fractures3 cases of postoperative perforation of the helical blade into
the hip joint. J Orthop Trauma. 2008; 22(10):731-736.
- Müller ME, Nazarian S, Koch P. The Comprehensive
Classification of Fractures of Long Bones. Berlin, Germany: Springer;
- American Society of Anaesthesiologists. New classification of
physical status.Anaesthesiology. 1963; (24):111-114.
- Vidyadhara S, Rao SK. One and two femoral neck screws with
intramedullary nails for unstable trochanteric fractures of femur in the
elderlyrandomised clinical trial [published online ahead of print October
16, 2006]. Injury. 2007; 38(7):806-814.
- Harris WH. Traumatic arthritis of the hip after dislocation and
acetabular fractures: treatment by mold arthroplasty. An end-result study using
a new method of result evaluation. J Bone Joint Surg Am. 1969;
- Haidukewych GJ, Israel TA, Berry DJ. Reverse obliquity fractures of
the intertrochanteric region of the femur. J Bone Joint Surg Am. 2001;
- Adams CI, Robinson CM, Court-Brown CM, McQueen MM. Prospective
randomized controlled trial of an intramedullary nail versus dynamic screw and
plate for intertrochanteric fractures of the femur. J Orthop Trauma.
- Liu Y, Tao R, Liu F, et al. Mid-term outcomes after intramedullary
fixation of peritrochanteric femoral fractures using the new proximal femoral
nail antirotation (proximal femoral nail antirotation) [published online ahead
of print May 15, 2010]. Injury. 2010; 41(8):810-817.
- Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM. The value of the
tip-apex distance in predicting failure of fixation of peritrochanteric
fractures of the hip. J Bone Joint Surg Am. 1995; 77(7):1058-1064.
- 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.
- Friedl W, Colombo-Benkmann M, Dockter S, Machens HG, Mieck U. Gamma
nail osteosynthesis of per- and subtrochanteric femoral fractures. 4 years
experiences and their consequences for further implant development.
Chirurg. 1994; (65):953-963.
- Pratt DJ, Papagiannopoulos G, Rees PH, Quinnell R. The effects of
medullary reaming on the torsional strength of the femur. Injury. 1987;
- Williams WW, Parker BC. Complications associated with the use of
the gamma nail. Injury. 1992; 23(5):291-292.
- Herrera A, Domingo LJ, Calvo A, Martinez A, Cuenca J. A comparative
study of trochanteric fractures treated with the Gamma nail or the proximal
femoral nail [published online ahead of print July 31, 2002]. Int
Orthop. 2002; 26(6):365-369.
- Takigami I, Ohara A, Yamanaka K. Treatment and surgical technique
for trochanteric fracture of the femur with proximal femoral nail.
(Seikeigeka) Orthop Surg. 2005; 56(2):1747-1750.
Drs Lv, Liu, Wang, Zhang, and Song and Messrs Fang and Yang are from the
Department of Orthopedic Surgery, West China Hospital, Sichuan University,
Drs Lv, Liu, Wang, Zhang, and Song and Messrs Fang and Yang have no
relevant financial relationships to disclose.
Correspondence should be addressed to: Yue Fang, MS, Department of
Orthopedic Surgery, West China Hospital, Sichuan University, 37 Guo Xue Xiang,
Chengdu, Sichuan Province, 610041, China (firstname.lastname@example.org).