Gamma nail breakage: a report of four cases.

Abstract

Gamma nails have been used extensively for the treatment of proximal femoral fractures. Nail breakage at the level of the aperture of the lag screw is rare. We report 4 such cases mainly associated with a large posteromedial cortex gap and nonunion. The need for adequate reduction to avoid such a complication is emphasised.

Full text

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ABSTRACT
Gamma nails have been used extensively for the
treatment of proximal femoral fractures. Nail breakage
at the level of the aperture of the lag screw is rare.
We report 4 such cases mainly associated with a large
posteromedial cortex gap and nonunion. The need
for adequate reduction to avoid such a complication
is emphasised.
Key words: bone nails; equipment failure; femoral neck
fractures
INTRODUCTION
Intramedullary nails combined with sliding hip
screws are increasingly popular for internal fixation
of proximal femoral fractures. Their biological
advantages are that the closed technique retains the
fracture haematoma1 and involves less operating
time and blood loss.2,3 Current trends in orthopaedic
surgery aim for small exposures and minimally
Gamma nail breakage: a report of four cases
GB Kasimatis, E Lambiris, M Tyllianakis, D Giannikas
Department of Orthopaedic Surgery, University Hospital of Patras, Greece
D Mouzakis
Department of Materials Science, University of Patras, Greece
E Panagiotopoulos
Department of Orthopaedic Surgery, University Hospital of Patras, Greece
Address correspondence and reprint requests to: Dr Georgios Kasimatis, Papanikolaou st, University Hospital of Patras, 26504
Rion-Patras, Greece. E-mail: g.kasimatis@gmail.com
Journal of Orthopaedic Surgery 2007;15(3):368-72
invasive techniques, in order to minimise both
the insult to the surrounding soft tissues and the
subsequent blood loss.4
Gamma nails combine intramedullary fixation in
the femoral shaft with a sliding screw in the femoral
head, allowing controlled collapse of the fracture,
while the intramedullary nail acts as a buttress
limiting excessive shaft medialisation in unstable
pertrochanteric fractures.5
Gamma nail breakage at the level of the aperture
of the lag screw is rare, and is mainly associated
with delayed union or nonunion and premature full
weight bearing. We report 4 such cases and discuss
their causes.
CASE REPORTS
Case 1
In May 1994, a 42-year-old man presented with
a very unstable intertrochanteric fracture with a
posteromedial cortical deficit after a motor vehicle
accident. Reduction was considered satisfactory, but
the posteromedial gap remained after fixation with

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Vol. 15 No. 3, December 2007 Gamma nail breakage 369
eventually developed cut-out of the femoral head
and underwent total hip arthroplasty.
Case 4
In September 2002, a 73-year-old man presented with
a painful hip caused by a partial subtrochanteric
fracture of the lateral cortex of the right femur. He
had metastatic prostate cancer and had undergone
radiotherapy for osteolytic lesions in his right
humerus and femur 4 months earlier. Prophylactic
osteosynthesis with a trochanteric Gamma nail was
selected because of his worsening pain and medical
history. Nine months later, he reported a painful right
hip again caused by nail breakage (Fig. 4). Because
of intra-operative difficulty with placement of a long
Gamma nail, due to the inadequate grip of the screw
in the femoral head, a 130º blade plate was used. At
the 10-month follow-up, he was able to walk, fully
weight bearing, but eventually died of his disease 3
months later.
DISCUSSION
Although some authors state that intramedullary hip
screws have not been shown to be superior to sliding
hip screws for the treatment of intertrochanteric hip
fractures,6 they may have selected indications, such
as the reverse-obliquity intertrochanteric hip fracture,
the intertrochanteric fracture with subtrochanteric
extension (requiring a long side plate), and
subtrochanteric femoral fractures.7
The standard Gamma
biomechanically evaluated in stable and unstable
nails have been
Figure 1 Radiographs
intertrochanteric fracture treated with a standard Gamma
nail, (b) nail breakage that occurred 5 months later, and
(c) a long Gamma nail used for osteosynthesis.
showing
(a) an unstable
a standard Gamma nail. Five months later, the nail
broke while the patient was on partial weight bearing
(Fig. 1). Osteosynthesis with a long Gamma nail
resulted in bone union, and the patient was able to
walk, full weight bearing, at the 5-year follow-up.
Case 2
In August 1991, an 82-year-old woman presented with
a subtrochanteric fracture after a fall. She underwent
fixation with a standard Gamma nail. Postoperative
radiographs showed no evidence of union with a
progressive varus deformity and rotation of the
proximal fragment. Seven months later, the nail broke
after a fall (Fig. 2). She underwent implant removal
and hemiarthroplasty. She was able to bear weight
with 2 crutches one year later.
Case 3
In December 2002, a 78-year-old obese woman
presented with a very unstable intertrochanteric
fracture with subtrochanteric extension after a fall.
She underwent fixation with a long Gamma nail
and a 12-mm hip screw. Postoperative radiographs
showed a large posteromedial gap. Eight months
later, she lost her balance and fell again and broke the
nail (Fig. 3). She underwent revision surgery using
a 12.7-mm sliding hip screw and calcium sulphate
bone graft substitute (Osteoset T pellets), to ensure
adequate grip of the new sliding hip screw inside
the old screw hole, as osteoporosis is common in
elderly patients. 12 months after revision, the patient
was able to walk painlessly with one crutch, but she
(a)(b)(c)
Figure 2 Radiographs showing (a) a subtrochanteric
fracture in an 82-year-old woman, (b) fixation using a
standard Gamma nail, and (c) nail breakage after a fall.
(a)(b) (c)

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370 GB Kasimatis et al.
Journal of Orthopaedic Surgery
intertrochanteric fractures in a cadaveric model.8
The Gamma nails have been shown to transmit
decreasing load to the calcar with decreasing fracture
stability, so that no strain was put on bone in 4-part
fractures with the posteromedial fragment removed.
One might expect that the shortened lever arm and
intramedullary fixation of the Gamma nail would
medialise the load towards the calcar, but in fact the
inherent stiffness of the Gamma nail transmits loads
to the femur in a fashion analogous to that seen with
femoral prostheses.8
Good reduction and proper implants are
prerequisites for stability in the osteosynthesis of
unstable proximal femoral fractures. Gamma nails
show a 30% greater load to failure than sliding hip
screws.9 Earlier studies reported no Gamma nail
breakage, noting that the greater strength of the
Gamma nail may not be necessary for intertrochanteric
(a)(b)(c)
Figure 4 Radiographs showing (a) a pathological fracture of the lateral cortex, (b) fixation using a trochanteric Gamma
nail, (c) nail breakage, and (d) revision with a 130º blade plate.
(d)
Figure 3 Radiographs showing (a) a very unstable intertrochanteric fracture with subtrochanteric extension, (b) fixation
using a long Gamma nail, (c) nonunion of the bone and breakage of the lag screw at the level of the aperture at 8 months,
(d) the fractured nail, and (e) revision with a sliding hip screw and calcium sulphate bone graft substitute.
(a)(b) (c)(d) (e)

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Vol. 15 No. 3, December 2007 Gamma nail breakage 371
the level of the aperture of the lag screw have been
reported since,10–13 mainly associated with delayed
union or nonunion and premature full weight
bearing.
In a series of 2500 Gamma nail fixations, only 4
(0.16%) nails broke, all associated with nonunion
and continued weight bearing. Breakage time
varied from postoperative month 6 to 15, suggesting
fatigue caused by dynamic loading.11 In a series
of 839 patients, 2 fatigue fractures at the cranial
aperture of the distal locking holes were reported.14
In a series of 224 patients, one nail breakage at the
level of the aperture of the lag screw was reported. It
was a standard Gamma nail, and the manufacturer
reported a material failure caused by an eccentric
insertion of the lag screw.12 Two breakages of standard
Gamma nails in the same patient were reported. The
possibility of septic nonunion or pathological fracture
was excluded. There were no signs of fatigue failure
in the nail surface and it was decided that weakness
at manufacture was the cause.13 Gamma nails are
susceptible to breakage at the weakest point—the lag-
screw interface.10
In our series, there were 4 breakages out of 412
Gamma nails used. Although nonunion in proximal
femoral fractures is uncommon, it may occur in
high-energy fractures as in case 1, and those of very
old age as in case 2. Both patients were operated on
during the early phase of the study and received
standard Gamma nails, which are no longer in use.
Technical errors, such as wrong placement of the set
screw preventing sliding, may also be contributing
factors. Patient 3 received a long Gamma nail
that was designed to withstand heavy loads. We
therefore investigated the surface of the broken nail
using photomicrographs taken by scanning electron
microscopy (SEM) [Fig. 5]. We examined one of the
2 identical parts surrounding the lag screw in the
long Gamma nail. The fracture surface was mainly
composed of 2 areas with distinctively different fracture
morphologies. In Figure 5, region A was marked
by a very brittle fracture pattern in which no large
plastic deformations can be observed, whereas region
B presented a highly anomalous profile over which
large plastic deformations dominate. The fracture
appears to have occurred in 2 stages; the breakage
occurred with a time lag between the initial cracking
and final rupture. The fracture pattern of region A
was almost even, with no large surface anomalies;
overall a very brittle fracture. This type of failure in
metals and alloys corresponds to an overstressing or
high-energy fracture, as no initial cracking, or any
other defect on the outside surfaces or even pores of
the metal bulk can be observed. Further evidence of
Figure 5 Microphotographs taken by scanning electron
microscopy showing (a) the left flap (outside) of the
fracture surface of the long Gamma nail, (b) and (c) the
right flap of the fracture surface A and B (end-region);
several striations correspond to crack arrest lines (arrows)
formed during the failure process.
(a)
2 mm
A
B
(c)
1 mm
Screw
apperture wall
(b)
Screw
apperture wall
fractures, unless these have a subtrochanteric
extension.6 Nevertheless, 8 cases of nail breakage at

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372 GB Kasimatis et al.
Journal of Orthopaedic Surgery
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Injury 1999;30:91–9.
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the evolution of the rupture and final breakage was
seen at the right flap of the fracture surface region
B (end-region). The Gamma nail was overloaded by
stress or strain causing initial brittle cracking on the
left and right sides of the lag screw aperture shaft.
Almost half of the implant load-bearing cross-section
was cracked and therefore unable to bear loads. The
remaining intact cross-section around the lag screw
was unable to provide sufficient load bearing. It broke
because of high stress (or strain) low cycle fatigue
under normal conditions, marked by large plastic
deformations. Given the severe instability of the
fracture pattern in this obese patient, we should have
paid more attention to the posteromedial gap. The
absence of any bony apposition in the posteromedial
cortex should have necessitated
weight bearing, at least in the early phase of callus
formation, to avoid excessive loading of the nail. In
patient 4, who had metastatic disease, reduction was
considered adequate despite a little varus deformity.
Nonetheless, the varus deformity progressed and
the fracture did not heal, resulting in nail breakage.
Nonunion in metastatic bone pushes the nail material
touch-down
to the limit of its tolerance. The use of a load-bearing
device such as the long Gamma nail might have been
more appropriate, but breakage of the long Gamma
nail has also been reported.15,16 Because the proximal
parts of the trochanteric and long Gamma nails are
the same, their risks of breaking are similar.
CONCLUSION
Gamma nails are useful in the treatment of proximal
femoral fractures and have a low implant failure
rate. Fracture instability may affect the nail breakage
rate. When there is a large posteromedial gap with
no bony apposition to transfer loads, non-weight
bearing is necessary to protect the nail. Although
closed reduction and minimally invasive exposure
minimise complications such as delayed union and
nonunion, prompt revision may be necessary when
such complications occur. When the reduction is
inadequate with no posteromedial support, it is
important that protected weight bearing should
continue until callus consolidation.