Abstract: A brief technique to place a cement plug on top of a polyethylene is presented. This technique has helped the authors obtain better cement mantles when they are plugging the canal in total hip replacement. Key words: femoral intramedullary plug, cemented hip arthroplasty, technique, biomechanical studies, hip replacement. Currently, more than 200,000 hemiarthroplasties and total hip replacements are performed every year in the United States  First-generation cementing techniques consisted of hand mixing of the cement and finger packing of the cement into the femoral canal. Modern (secondgeneration) cementing techniques consist of pressurized insertion of the cement, centrifugation or vacuum mixing, and plugging of the intramedullary canal. These changes decrease the porosity of th

MD Carlos J Lavernia

MD Patrick Owens

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The Journal of Arthroplasty Vol. 14 No. 3 1999 
Brief Communication 
Technique for a Composite Femoral 
Intramedullary Plug in Cemented Hip 
Arthroplasty 
P a t r i c k  O w e n s ,  M D ,  a n d  C a r l o s  J. L a v e r n i a ,  M D  
Abstract: A brief technique to place a cement plug on top of a polyethylene is 
presented. This technique has helped the authors obtain better cement mantles when 
they are plugging the canal in total hip replacement. Key words: femoral intramed- 
ullary plug, cemented hip arthroplasty, technique, biomechanical studies, hip 
replacement. 
Currently, more  than  200,000 hemiarthroplasties 
and total hip replacements are per formed every 
year in the United States [1]. Modern  cementing 
techniques have considerably improved the longev- 
ity of total hip replacement  [2]. Data have demon-  
strated a femoral  loosening rate of < 3 % at 10 years 
with the use of a cemented  femoral  componen t  [3]. 
In contrast, most  cementless series have significant 
osteolytic changes and high failure rates after only 7 
years [4,5]. In light of these data, an increasing 
numbe r  of surgeons are using a cemented  femoral  
component .  
First-generation cement ing techniques consisted 
of hand  mixing of the cement  and finger packing of 
the cement  into the femoral  canal. Modern  (second- 
generation) cementing techniques consist of pressur- 
ized insertion of the cement,  centrifugation or 
vacuum mixing, and plugging of the intramedullary 
canal. These changes decrease the porosity of the 
From the Departments of Orthopaedic Surgery and Biomedical 
Engineering and Division of Arthritis Surgery, University of Miami 
School of Medicine, Miami, Florida. 
Submitted September 16, 1997; accepted April 30, 1998. 
Reprint requests: Carlos J. Lavernia, MD, 13 2I NW 14th 
Street, Suite 203, Miami, FL 33125. 
Copyright © 1999 by Churchill Livingstone ® 
0883-5403/99/1403-00165 I0.00/0 
cement,  increasing its fatigue strength. Pierson and 
Harris [6] demonstra ted the improvement  in clinical 
ou tcome observed with mode rn  cementing tech- 
niques. 
Biomechanical  studies have been performed to 
determine the effects of centrifugation and vacuum 
mixing on the mechanical  properties of polymethyl-  
methacrylate  (PMMA) {7,8]. These studies clearly 
have demonstra ted the beneficial effects of the 
preinsertion treatments of PMMA. Pressurized inser- 
t ion of the cement  has also been the subject of 
several investigations [9,10] and has been  shown to 
have a significant effect on the strength of the 
cemen t -bone  interface strength [10]. 
The intramedullary plug prevents cement  f rom 
being displaced distally in the femoral  canal at the 
time of cement  pressurization and allows for higher  
cement  intrusion pressures. High insertion pres- 
sures allow for better  penetra t ion of the cement  into 
the endosteal cancellous surface, creating a stronger 
b o n e - c e m e n t  interface { i i ]. The increased interface 
strength has resulted in a longer clinical life for total 
hip replacements [2,3,6]. Hungerford and Krackow 
[12] introduced a new technique using a plastic 
cement  restrictor designed for use in acetabular 
per fora t ion- - the  Mexican hat--as a femoral  intra- 
369 
370 The Journal of ArthroplastyVol. 14 No. 3April 1999 
medullary plug. Mallory [13] introduced a bullet- 
tipped, flanged polyethylene plug for use in occlu- 
sion of the canal. 
We published a study that demonstrated the 
superiority of PMMA plugs over synthetic and bone 
plugs in cadaveric bone. At that time, however, only 
2 commercially available polyethylene plugs were 
obtainable in the market. In 1996, at least 8 differ- 
ent companies manufactured plugs of different styles 
and designs. Some of these plugs are of universal 
size and are to be used in every femur. Some of 
them have sizers that allow the surgeon to select the 
appropriate plug. In a laboratory study of synthetic 
plugs, there was a high incidence of both cement 
leakage and distal migration when subjected to 
pressurization [14]. In a study using cadaveric 
femora, most of the plugs tested were unable to 
withstand pressures of 50 psi, a pressure below the 
average produced by commercially available ce- 
ment guns during pressurization. PMMA plugs had 
no migration or cement leakage at pressures above 
100 psi for longer than 6 minutes [15]. These studies 
were done in cadaveric bone without intramedul- 
lary bone circulation. Insertion of a PMMA plug in 
the presence of active intramedullary bleeding is 
more difficult. 
A technique similar to ours was described by 
Harris and McLaughlin in 1993 [16]. This article 
describes a modified technique that allows easier, 
more accurate insertion of a PMMA plug. Pie 
currently employ a technique using polyethylene 
and PMMA plugs together, which combines the 
advantages of both plugs. The polyethylene plug 
allows for accurate depth placement of the femoral 
restrictor and decreases the volume of cement 
needed to make an adequate PMMA plug. The 
PMMA plug then gives the restrictor greater strength 
for cement pressurization without cement leakage. 
Technique 
The proximal portion of the femur is exposed, and 
the femoral neck is cut in the standard fashion. The 
femoral canal is then reamed with straight reamers 
followed by serial broaching. Trial components are 
then placed, and a trial reduction is performed to 
confirm the correct size of the components. The trial 
components are then removed. The femoral canal is 
then prepared by pulsatile lavage, brushing, and 
drying. The canal diameter at a level 2 to 3 cm below 
the anticipated end of the prosthesis is measured 
using a commercially available measuring device, 
and a plug size is selected. We use a polyethylene 
plug manufactured by DePuy, and there are 7 
different plug sizes (range, 8.5 to 23.5 mm). The 
Fig. 1. Cement being placed in syringe. 
recommended plug diameter should be at least 1 
mm greater than the canal width. The plug is then 
inserted to a level 2 to 3 cm below the tip of the 
prosthesis. The canal is then packed with epineph- 
rine-soaked gauze sponges to inhibit venous bleed- 
ing. The epinephrine mixture is made by adding 5 
1-mL ampules of a 1:1,000 solution of epinephrine 
to 500 mL of normal saline solution to make a 
concentration of 1:100,000. 
One half pack of Simplex-P cement (Howmedica, 
Rutherford, N J) is then prepared using the manufac- 
turer's specifications. When the cement no longer 
sticks to the surgeon's glove, it is placed into a 
medullary plug syringe. This syringe is a long nar- 
row syringe that is calibrated from distal to proximal 
Fig. 2. Cement plug being delivered. 
Composite Femoral Intramedullary Plug:ATechnique • Owens and Lavernia 371 
with volume in cubic centimeters on one side and 
distance in centimeters on the other (Fig. 1). Five to 
10 cm 3 of cement  is placed into the syringe, and all 
but  1.5 cm 3 is discarded (Fig. 2). 
The epinephrine-soaked sponges are then  re- 
moved,  and the canal is dried. The syringe is then 
placed into the medullary canal to the level of the 
medullary plug, and the cement  is injected. The 
syringe is then rotated several times clockwise and 
several times counterclockwise to free the cement  
f rom the syringe. This rotation must  be done to 
prevent  removal  of the cement  plug with with- 
drawal of the syringe. 
The distal end of the syringe is rubbed into the 
patient's subcutaneous fat to prevent  it f rom stick- 
ing to the cement. It is then  reinserted into the 
medullary canal, and the cement  plug is tamped 
gently into place. Using the calibrated portion of the 
syringe, the depth of the plug is measured to ensure 
it is at least 1.5 cm beyond  the anticipated level of 
the tip of the prosthesis. The syringe is then re- 
moved.  The trial broach is then inserted to assure 
the surgeon that there is enough  space for the actual 
prosthetic devices. At this time, mixing of the 
cement  for insertion of the femoral componen t  is 
begun, and by the time it is ready for injection, the 
cement  port ion of the plug is polymerized and 
securely bonded  to the wall of the femur. 
Potential problems with our technique include 
the cost of purchasing the syringe and the second 
half batch of cement.  The time factor is also an 
additional cost. The total cost of the material pur- 
chases is about  $150.00. The amoun t  of time in- 
volved in allowing the plug to dry costs approxi- 
mately an additional $150.00. Long-term outcome 
of cemented devices is affected by the quality of the 
cement  mantle  [3]. Additional costs involving the 
placement  of this cement  plug should be offset by 
increased longevity of the stem. 
Potential complications of our technique include 
the errant cement.  This could cause problems dur- 
ing the insertion of the stem. Such problems can be 
avoided by placing the broach within the canal 
while the plug is hardening. The bot tom of the rasp 
pushes the soft plug distally and does not  allow 
cement  to interfere with the centralizer on the stem. 
Our technique is probably best suited for patients 
with wide medullary canals. In standard femurs, the 
off-the-shelf polyethylene plugs probably suffice. 
References 
1. Office of Health Research Statistics and Technology. 
National Center for Health Statistics; Rockville, MD, 
1997 
2. Barrack RL, Mulroy RD, Harris WH: Improved cement- 
ing techniques and femoral component loosening in 
young patients with hip arthroplasty. J Bone Joint 
Surg Br 74:560, 1992 
3. Mukoy RE), Harris WH: The effect of h~proved cement- 
ing techniques on componem loosening in total hip 
replacement. J Bone Joint Surg Br 72:373, 1990 
4. Kim YH, Kim VE: Cementless porous-coated ana- 
tomic medullary locking hip prosthesis. J Arthro- 
plasty 9:230, 1994 
5. Kim YH, Kim VE: Results of the Harris-Galante cement- 
less hip prosthesis. J Bone Joint Surg Br 74:62, 1992 
6. Pierson JL, Harris WH: Comparisons of first and 
second generation femoral cement for revision sur- 
gery. Presented to the AAOS, 1993, San Francisco 
7. Burke DW, Gates EI, Harris WH: Centrifugation as a 
method of improving tensile and fatigue properties of 
acrylic bone cement. J Bone Joint Surg Am 66:75, 1984 
8. Lidgren L, Drar H, Moller J: Strength of polymethyl- 
methacrylate increased by vacuum mixing. Acta Or- 
thop Scand 55:375, 1984 
9. Dorr LD, Lindber JP, Claude-Faugere M, Malluche 
HH: Factors influencing the intrusion of methymeth- 
acrylate into human tibiae. Clinical Orthopaedics and 
Related Research 183:382, 1984 
10. Lavernia C J: Sustained pressurization of PMMA--a 
biomechanical study of the bone cement inter- 
face--an in vitro and in vivo comparison. Presented 
at the Orthopaedic Research Society Poster Session, 
Las Vegas, NV, 1989 
11. Oh I, Carlson CE, Harris WH, et al: Improved fixation 
of the femoral component after total hip replacement 
using a methacrylate intramedullary plug. J Bone 
Joint Surg Am 60:262, 1978 
12. Hungerford DS, Krackow ICA: A convenient distal 
plug for the femoral cavity in total hip arthroplasty. 
CORR 154:57, 1981 
13. Mallory TH: A plastic intermedullary plug for total hip 
arthroplasty. CORR 155:55, 1981 
14. Johnson JA, Johnston D, Hawary RE, et al: Occlusion 
and stability of synthetic femoral canal plugs used in 
cemented hip arthroplasty. J Appl Biomat 6:63, 1995 
15. Maltry JA, Noble PC, Kamaric E, Tullos HS: Factors 
influencing pressurization of the femoral canal dur- 
ing cemented total hip arthroplasty. J Arthroplasty 
10:77, 1995 
16. Harris WH, McLaughlin JR: A composite plug for 
occluding the femoral canal prior to cementing a total 
hip femoral component. Orthop Rev 23:344, 1994 


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