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OPEN REDUCTEGN ANB FEXATION OF
ACETABULAR FRAC?GRES ‘ZN THE 33G

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RENEE-A}! STA‘E‘E CREVER‘SCTY

James Stanley Larsen
1961

 

L I B R A R Y
Michigan State
University

 

ABSTRACT

‘OPEN REDUCTION AND FIXATION OF
ACETABULAR FRACTURES IN THE DOG

by James Stanley Larsen

An investigation was made into methods of surgical
management of pelvic fractures in the dog. The methods
explored were: (1) external fixation by mechanical de-
vices and (2) open reduction and internal fixation with
screws, pins and plates. Pelvic fractures were created
experimentally by driving the femoral head against the
acetabulum by means of force applied to the greater
trochanteric area of the femur. The paper reports on a
series of ten acetabular fractures. In this series, uni-
lateral acetabular fractures were repaired by open reduc-
tion and internal fixation. The fracture site was ex-
posed by Brown's (1953) dorsal surgical approach to the
coxofemoral joint; the fracture was reduced mechanically
with a large modified towel clamp and fixed with a single
stainless steel screw inserted across the fracture line.
-Results were variable, ranging from restoration of normal
function to severe lameness because of avascular necrosis

of the femoral head. All ten cases showed moderate to

James Stanley Larsen

marked fibrosis of the coxofemoral joint capsule at

necropsy.

OPEN REDUCTION AND FIXATION OF

ACETABULAR FRACTURES IN THE DOG

BY

James Stanley Larsen

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER.OF-SCIENCE

Department of Surgery and Medicine

1961

ACKNOWLEDGEMENTS

Special thanks are accorded to Dr. William V. Lumb and
Dr. G.H. Conner for their guidance and help and to the
Mark L. Morris Animal Foundation whose grant made this
study possible. The author would also like to thank
Dr. Wade 0. Brinker, Head of the Department of Surgery
and Medicine, Dr. U.V. Mostosky for radiographic assis-
tance, co-worker Dr. E.W} Van Stee, and my wife Martha

Kay for help in the preparation of the manuscript.

ii

Table of Contents

Chapter Page
I. Introduction .................................... 1
II. Literature Review ............................... 3
A. Anatomical Considerations ................... 3

B. .Etiology and Incidence of Pelvic Fractures.. 4

C. Management of Pelvic Fractures--Veterinary.. 6

D. Management of Pelvic Fractures--Human ....... 11

III. Materials and Methods ........................... 15
A. Preliminary Investigative Procedures ........ 15

B. Experimental Design ..... ‘ .................... 21

‘C. Materials ................................... 22

D. Surgical Technique .......................... 27

E. Method of Evaluation ...... ‘ .................. 33

IV. .Results ......................................... 34
V. Discussion ...................................... 46
VI. .Conclusions ..................................... 51
-References ...................................... 53

iii

List of Tables

Table Page
I. Experimentally produced pelvic fractures ........ 35
II. Clinical evaluation of healed pelvic fractures..36

III. Description of healed fracture sites of macer-
ated pelves and femora .......................... 37

iv

List of Figures

Figure Page
1. Modified Roger Anderson Splint .................... l7
2. Turnbuckles applied to the bony pelvis ............ l9
3. Experimental method of creating pelvic fractures..24
4. Orthopedic equipment used in reduction and

fixation of central acetabular fractures .......... 26
5. Method of reduction and fixation of central

acetabular fracture in the dog .................... 31
6. Line drawings of pelvic radiographs of

experimental animals .............................. 39
7. Line drawings of pelvic radiographs of

experimental animals .............................. 41
8. Dog K-26, a favorable example ..................... 43
9. «Dog K—27, an unfavorable example .................. 45

Chapter I

Introduction

With advent of the automdbile, there has been
an increase in the number of fractures occurring in
dogs. According to Brinker (1959), pelvic fractures
comprise 16.4 per cent of all fractures seen in the
dog. This is the second most common type, only fe-
moral fractures occurring more frequently. In spite
of these significant numbers, the management of pel-
vic fractures has not changed measurably in recent
years, as contrasted to other advances in canine
orthopedics.

The conservative treatment of pelvic fractures,
that of confinement and supportive care, is practi-
cal and effective in many cases but what happens to
those cases of severe displacement and acetabular
involvement which do not respond to conservative
treatment? Too often lameness, deformity, dbstipa—
tion and dystocia are the end results of severe‘
acetabular fractures.

This dissertation deals with the surgical man-
agement of experimentally produced pelvic fractures

and a method of Open reduction and fixation of

acetabular fractures by means of a bone screw.

In this study the principle stated by Knight and
Smith, (1958) "That the more anatomical the reduction,
the earlier will be the return to function; and the
more nearly normal the result, the less frequently

will degenerative changes develop," served as a guide.

Chapter II

Literature Review

A. Anatomical Considerations

The word pelvis (L. "basin") has been defined
as the basin-shaped ring of bone at the posterior
extremity of the trunk supporting the spinal column
and resting upon the lower extremities. It is com-
posed of the two innominate bones laterally and ven-
trally, and the sacrum and coccyx dorsally (Dorland,
1951).

The acetabulum (L. "vinegar-cruet") is a cup-
shaped cavity on the lateral surface of the os coxa
in which the head of the femur articulates. 22, gig.
This joint cavity is formed where the ilium, ischium
and pubis meet. These three bones, along with the
small acetabular bone located in the wall of the ace-
tabulum, fuse at about the fourth month in the dog
(Miller, 1948).

Twenty-five muscles attach directly to the pel-
vic bones. They can be classified into four main
groups according to function: (1) extensors of the
hip joint supplied by the sciatic nerve, (2) flexors

of the hip joint innervated by the femoral nerve,

(3) adductors of the hip joint supplied by the db-
turator nerve and (4) abductors and extensors of the
hip joint supplied by branches of the sciatic nerve.

The femoral nerve is most often formed by bran-
ches of the fourth, fifth and sixth lumbar nerves.
It passes through the ilio—psoas muscle to which it
supplies branches and ends in the anterior thigh
muscles. The sciatic nerve is formed by branches of
the last two lumbar and first and second sacral nerves.
It penetrates the greater sciatic foramen to supply
the posterior muscles of the thigh. The obturator
nerve derives its origin from fibers of the fourth,
fifth and sixth lumbar nerves. It courses along the
medial surface of the shaft of the ilium and disap-
pears through the Obturator foramen to supply the
external obturator, pectineus, adductor and gracilis
muscles (Miller, 1948).
B. Etiology and Incidence of Pelvic Fractures

A tremendous amount of force is required to
fracture the pelvis. In a survey of fifty-six cases
of human pelvic fractures, Conway (1935) stated that

46 per cent were the result of falls from great height

and 41 per cent from automobile accidents. In the pro-
duction of fractures on skeletal human femora, still
articulated with the pelvis, Smith (1953) calculated a
force of 288 foot-pounds applied to the femur was neces-
sary to fracture the acetabulum.

In a survey of fifty canine and feline pelvic
fractures presented to the small animal clinic at Michi-
gan State University, automobile accidents were respon-
sible for all of the cases except one which was caused
by being run over by a wagon. In nearly all these cases,
fractures involved more than one of the pelvic bones.
The incidence of involvement was: pubis, 86 per cent;
ischium, 44 per cent; acetabulum, 40 per cent; ilium,

38 per cent; sacroiliac, 16 per cent. Ten of these
cases were managed with intramedullary pinning, three
by Kirschner half-pin assemblies, three by euthanasia
and the rest treated by cage rest and supportive care.
Leonard (1960) stated that pelvic fractures comprised
23.5 per cent of all fractures seen at the Cornell
small animal clinic, and of those, 89 per cent in—

volved the ilium.

C. Management of Pelvic Fractures--Veterinary

Ehmer (1934) advised conservative treatment of
canine pelvic fractures by attempting to press the
bones into place, confining the animal in a small
area and making it as comfortable as possible. He
described the single sling and the spread cast for
use in some types of pelvic fractures, but added that
most casts do little or no good and only add to the
misery of the animal.

Knowles gt 31. (1949) advanced the use of the
Kirschner half-pin splint in cases of acetabular
involvement or where displacement of parts was such
as to result in unsightly lameness. They emphasized
the importance of careful radiographic interpretation
and the selection of a fragment of bone that was solid
to form an anchor for the splint. The realignment of
parts was determined by digital palpation per rectum
and by radiographs. Olsen (1959) recommended the
Kirschner splint for the management of separation of
the symphysis pubis, sacroiliac separation and ace-
tabular fracture. He chose the tuber sacrale, shaft

of the ilium, body of the ischium and the tuber ischii

as locations for the placement of the pins. He stated
that usually the pins and pin assembly could be removed
in two or three weeks. Henley (1955) reported the
successful management of a case of pelvic and femoral
neck fracture with the Kirschner splint and a femoral
head prosthesis.

Brinker (1959) classified pelvic fractures into
three groups: (1) those which heal satisfactorily
without specific treatment, (2) those benefited by spe-
cific treatment and (3) those damaged beyond satisfac-
tory repair. He advocated the use of threaded shoulder
pins instead of trocar point pins when used with half-
pin assemblies. In cases involving the acetabulum,
he suggested an open approach to the coxofemoral joint
to allow prying the fracture segments into alignment
and the insertion of intramedullary or diagonal pins
for fixation. Injury of nerves, urethra, bladder and
intestine were mentioned by Brinker as complicating
soft tissue sequelae of pelvic fractures. The absence
of urine after catheterization helped to diagnose rup-
ture of the urinary bladder. He discouraged the use of

casts in the treatment of pelvic fractures since casts

tend to push the fractured bones into the pelvic canal.
In regard to the symptomatology of pelvic frac-
tures, Leonard (1960) made the following Observations.
Fractures of the pelvis were often multiple but sel-
dom compound and pain was a constant sign, but crepi-
tus might be difficult to elicit except in impacted
fractures of the acetabulum. In fractures of the shaft
of the ilium, the patient was usually able to sustain
weight but walked with difficulty. When the body of
the ischium or tuber ischii was fractured there was an
intermittent lameness of five to seven days. Separation
of the symphysis pubis caused inability to rise or bear
weight. Fractures through the acetabulum were Charac-
terized by a unilateral lameness, abduction of the limb
and limited joint movement. When intrapelvic luxation
of the femoral head was present, the trochanter major
was depressed, the rump appeared flattened and the af-
fected limb was shorter than its mate. In the treatment
of pelvic fractures, Leonard recommended the Kirschner
splint used in conjunction with beaded wires or bicycle
spokes placed through parts of the pelvis near the sur-

face so that a clevis can be formed with a pin bar to

prevent the pins from retracting. He stated that some
impacted fractures of the acetabulum can be managed by
straight leg traction to reduce the fracture, and the
application of a Thomas splint for ten days to two weeks.

Cawley and Archibald (1955) described an open ap-
proach with intramedullary pinning for fractures of the
shaft of the ilium. The fracture site was exposed by
incising the skin over the tuber sacrale and reflecting
the origin of the middle gluteal muscle. Fixation was
accomplished by a pin inserted in the medial side of
the ilial wing into the ilial shaft across the fracture
line.

A dorsal surgical approach to the coxofemoral joint
was described by Brown (1953) for the insertion of fe-
moral head prostheses in the dog and cat. In this ap-
proach, the skin was incised over the greater trochanter
and deepened to expose the anterior border of the biceps
femoris muscle. The biceps and tensor fascia lata were
separated to expose the gluteal muscles. The superficial,
middle and deep gluteal muscles were transected near their
insertions and reflected dorsally to expose the coxofemoral

joint. Closure was accomplished by suturing the severed

10

muscle attachments starting with the deep gluteal muscle.
A small hole was drilled through the dorsal lip of the
greater trochanter and a double suture passed through it
into the thick band of tissue found in the middle gluteal
muscle. The animal's leg was abducted and the closure
completed by suturing the rest of the middle gluteal,
the superficial gluteal and biceps muscles to the se-
vered fascia lata. A figure-eight single sling bandage
was applied and left on the leg for five days. In a
similar dorsal surgical approach Gorman (1955) performed
an osteotomy of the greater trochanter to leave the large
middle gluteal muscle firmly attached to bone. Upon clo-
sure of the surgical wound, the greater trochanter and
the attached muscle were returned to their normal posi-
tions and held in place with stainless steel wire.

Archibald £2.2£~ (1953) described an open approach
(attributed to Bottareli) to the coxofemoral joint for
the correction of coxofemoral luxations. Exposure of
the joint was made by separation of the vastus later-
alis and rectus femoris muscles.

A ventral surgical approach to the acetabulum was

reported by—Rieger (1956) in which the pectineus muscle

11

was transected and reflected to expose the acetabulum.
Once exposed, acetabular fragments were fixed with
stainless steel wire.
D. Management of Pelvic Fractures--Human.

vIn human medicine, pelvic fractures historically
have been treated conservatively. "The treatment con-
sists of binding the pelvis with a circular bandage" is
a typical statement from older surgical volumes (Skey,
1851). Plaster of paris double hip spicas (Rose, 1951:
Watson-Jones, 1955) or leg traction and hammock suspen-
sion (Nowland and Conwell, 1933) have been recommended.

Recently more radical treatments have been employed
for severe pelvic fractures. Key and Conwell (1942)
suggested fixation with small bone or ivory pegs. Levine
(1943) treated a caSe of central acetabular fracture with
a bone plate curved to fit the inner table of the pelvis.
Whiston (1953) described correction of a fractured ilial
wing by subperiosteal dissection to expose the fracture
site and fixation with two stainless steel pins.

Elliott (1956) in a paper on central fractures of
the acetabulum stated the mechanism of this injury was

force applied to the greater trochanteric region, the

12

head of the femur being driven centrally against the floor
of the acetabulum thus fracturing the acetabulum. This
fracture was observed in young adults or middle-aged
adults, since in older age groups the neck of the femur
fractured first, as a rule. He mentioned that a high
incidence of traumatic arthritis and frequent avascular
necrosis of the femoral head were present in this type
of fracture, which accounted for the poor prognosis. In
two cases he achieved a successful anatomical reduction
by the use of Hagie pins inserted across the fracture
line. The Hagie pins used were small lag screws with
threaded shafts upon which a nut and washer could be
placed to compress the fragments. The Smith-Peterson
anterior iliofemoral approach was used to expose the
acetabulum.

External fixation was employed by Johnson (1957) to
repair a comminuted pelvic fracture with avulsion of one-
half of the pelvis from the other. A turnbuckle was used
to approximate the fragments.

Stewart and Milford (1954) while showing contempt
for surgical management of comminution of the acetabulum,

stated these tenets: (1) that dislocation of the hip is

13

an emergency demanding immediate reduction; (2) that
postoperative immdbilization is necessary only to main-
tain stability; (3) that avascular necrosis is the end
result of disruption of the blood supply to the femoral
head. Speed and Knight (1956) avowed that it is essen-
tial to restore the normal anatomy of the hip as nearly
as possible and that any incongruity in the acetabular
wall is certain to produce a degree of traumatic
arthritis.

Knight and Smith (1958) used the face of a clock to
describe central acetabular fractures, twelve o'clock
being the top of the acetabular crescent. They felt that
it was most important to restore the weight-bearing vault
of the acetabulum or that area between two and ten o'clock.
Emphasis was placed on the importance of careful study of
stereoscopic radiographs for the correct interpretation
of fractures and proper choice of approach. They pre-
sented several cases of central acetabular fractures which
were managed surgically by anterior or posterior approaches
to the acetabulum and reduction by grasping pegs inserted
into each fragment with bone pliers. Fixation was ac-

complished with.Knowles pins inserted across the fracture

14

site. Aftercare of the patient with pelvic fracture was
greatly simplified by an anatomical open reduction.
Fixation and the return to function was more rapid than

following treatment by conservative methods.

Chapter III

Materials and Methods

A. Preliminary Investigative Procedures

At its inception this study was to be one of pelvic
fractures in the dog. Hope was high concerning the uti-
lization of a Roger Anderson Tru-Aligning Splint*, a de-
vice for the reduction of human long bone fractures, for
the reduction of pelvic fractures in the dog. After ex-
tensive modification and machine work of the model owned
by the Department of Surgery and Medicine (figure 1.),
reductions of several cases of pelvic fracture were at-
tempted. Corkscrews and Steinman pins bent to form hooks
were used to grasp the bony pelvis and these in turn were
fastened to the modified Roger Anderson splint. When at-
tached in this manner the fractured segments were mani-
pulated by adjustment of the many levers, joints and
screws on the device. Once reduction was achieved, im-
mdbilization was effected with Kirschner** or Tower*
assemblies.

Common turnbuckles were adapted to Kirschner equip-
ment to form an adjustable splint (figure 2.). .A Stein-
man pin was driven through both ilial wings just pos-

terior to the spinous process of the last lumbar

 

*fThe Tower Company, Inc., Seattle. Washington
Kirschner Manufacturing Co., Vashon. Washington

15

l6

.msumtmaam any
ee>o Lev—o; euuommmu coc_uo_ x cuc_uw cm
vcmjoom_a c_ renew—o mZOLUmxtou esp mc_zo;m

uc__am centevc< tomom vo_w_eoe < ._ ot:m_u

17

.H Guzman

 

 

18

Figure 2. Lateral and dorsal views of a
skeletal pelvis showing turnbuckles adapted
to Kirschner clamps and attached to the

pelvis with bone pins.

 

 

19

 

 

 

 

 

 

Figure 2.

20

vertebra to form a solid base from which to build a
splint. Adapted turnbuckles were attached to the Stein-
man pin at right angles and fastened to pins inserted in-
to both tuber ischia. A smaller turnbuckle completed the
rectangular shape of the splint. This splint allowed
gradual manipulation of fragments in anteroposterior and
lateromedial directions.

Several surgical approaches to the pelvis were
tried. The dorsal approach to the ilial shaft (Cawley
and Archibald, 1955), the ventral approach to the ace-
tabulum (Rieger, 1956), the dorsal approach to the coxo—
femoral joint (Brown, 1953) and a perineal approach to
the ischium. The latter consisted of an incision similar
to the one made in perineal herniorrhaphy and enabled the
operator to palpate the ilial body once the skin was in-
cised and fascia separated.

The use of Steinman pins, bone screws, bone screws
and standard bone plates, bone screws and homemade mal-
leable metal bone plates shaped to fit the pelvis, and
sheet metal rivets was explored in the fixation of a
variety of pelvic fractures produced on cadavers and

mascerated bony pelves.

21

»Considerable difficulty was encountered in creating
pelvic fractures severe enough to warrant radical treat-
ment without causing death from shock or hemorrhage.

When dogs anesthetized with sodium pentObarbital* were
struck over the pelvis with a sledge hammer, fatal shock
was frequent. Clamping the posterior quarters of anes-
thetized dogs in a large vise was totally ineffective.
Femoral head and neck fractures were common unwanted se-
quelae to severe blows over the trochanter major.

B. Experimental Design

It was decided that the prOblem should be restricted
to acetabular fractures in an attempt to narrow the field
of endeavor. Thirty dogs of mixed breeding Obtained from
a dog pound were selected for the final prOblem. The an—
imals were housed in individual cages in a kennel. A ra-
tion composed of two cups F/D** supplemented with 30 ml
of corn Oil and 5 ml of cod-liver oil mixed with two cups
of water was fed once daily on a weight basis. For ex—
ample, a twenty-pound dog received two and one-fourth
cups of the ration. The dogs were vaccinated against
canine distemper, infectious canine hepatitis and lep-

tospirosis. In only ten were suitable acetabular

 

Halatal, Jensen-Salsbery Laboratories, Inc., Kansas City,
*Missouri
"Prescription Diets Dept.", Hill Packing Co., Topeka,

”Run-\—

22

fractures produced and these ten dogs were used as the
final experimental group.

Each dog was anesthetized with thiamylal sodium*
and placed in lateral recumbancy on the floor with the
right side down. The left leg was flexed and held in
this position by means of a single sling of one-inch
adhesive tape to prevent excessive movement of the leg
(figure 3.). Cloth pads were placed under the right hip
to help cushion the blow and prevent fracture of the right
pelvic bones. A three-legged striker was placed over the
dog with its striking plate directly over the greater
trochanter Of the left femur. The top of the striker was
hit sharply by a full swing of a five-pound sledge hammer
to drive the femoral head against the acetabulum (figure 3.).
After the blow the pelvis was palpated rectally to esti-
mate the amount Of pelvic disruption. Ventro-dorsal and
lateral radiographs were taken and studied with a skeletal
pelvis in hand to help visualize the fractures.
C. Materials

In addition to the ordinary surgical instruments,
special orthopedic devices were used as follows:

(figure 4.)

 

*Surital, Parke, Davis & Co., Detroit, Michigan

23

Figure 3. Diagramatic illustrations showing
an anesthetized dog in lateral recumbancy
with a tape sling in place and a three-legged
striker in place over the greater trochanter

and the direction of applied force.

 

 

 

 

 

24

 

 

 

 

Figure 3.

25

Figure 4. Orthopedic instruments used in the
reduction and fixation of acetabular frac-
tures. A. An intramedullary pin drill and
Steinman pin, B. Drill key, C. Large
Backhaus towel clamp with straightened
prongs, D. An assortment of headless bone

screws, E. Small screw driver.

 

26

 

L\-\-\-\v\-\J-\v\-\-t\- \ L L \- \- \.

 

 

 

 

 

 

 

Figure 4.

27

l Kirschner intramedullary pin drill

1 Large Backhaus towel clamp with tips straightened
and cut Off
Headless, stainless steel bone screws

1 Small screw driver

2 Steinman pins, .080 and 3/32 inch diameters

l Osteotome

1 Straight two-inch needle

30-gauge stainless steel surgical wire
This equipment was made into a pack and sterilized in an
autoclave.

Two kinds of stainless steel bone screws were used:
Sherman-type, coarse-thread, .138—inch-diameter and fine-
thread, 3/32-inch-diameter. The heads of these screws
were cut Off and the top of the shank slotted. The final
lengths of the screws used were 3/4—inch, 7/8-inch and
one-inch. Screws prepared in this manner were Obtained
by special order from the Zimmer Manufacturing Company of
Warsaw, Indiana. It was felt that removal of the stan—
dard head would provide a neater junction of screw and
bone.

D. Surgical Technique

-On the day following the fracture, each dog was
anesthetized with sodium pentObarbital and placed on an
operating table on its right side. The hair of the left

hip was clipped from the dorsal midline to the stifle

28

extending from the flank to the anus, with a #404blade
Oster clipper. The skin was cleansed for surgery five
times with germicidal detergent* and covered with a sterile
drape in which there was an eight-inch opening. The dorsal
surgical approach to the coxofemoral joint as described

by Brown (1953) was employed on all dogs in the final ex-
perimental group.

.After the coxofemoral area was exposed, the fracture
site was determined and freed Of adherent muscle fibers
by use of an osteotome. In some instances it was necessary
to sever the tendon of the internal_dbturator muscle to
Obtain adequate exposure. A finger was then forced over
the dorsal border of the acetabulum and into the pelvic
canal. By digital manipulation the bone fragments were
brought into apposition and any medial displacement corrected.
It was found helpful to grasp the tuber ischii with a towel
clamp to aid in the reduction of the ischial fragment.

When reduction had been achieved, a hole was drilled
with a 3/32-inch trocar point Steinman pin on either side
of the fracture site through the lateral cortex of the
pelvis. The straightened prongs of a Backhaus towel clamp

were inSerted into these holes, final reduction was made

 

IEParke, Davis & Co., Detroit, Michigan

29

and then the towel clamp was tightly closed. Since
a central acetabular fracture presents a triangular
fracture surface, the break was nicely immObilized
when the towel clamp was closed (figure 5.).

Following reduction, a trocar-point Steinman pin,
the size of which was equal to the inside diameter Of
the chosen screw was driven Obliquely across the frac-
ture line from the extreme dorsum of the ilial frag-
ment downward into the ischial fragment. In heavily
muscled dogs it was necessary to penetrate the middle
gluteal muscle with the pin to Obtain the proper
angle across the fracture line. After the hole was
drilled, a headless screw of the proper length, as
determined by drill—pin penetration, was screwed
firmly across the fracture line with a small screw
driver (figure 5.). The towel clamp was removed after
the screw was in place and the stability of the repair
was tested. The joint capsule was sutured if possible,
but generally it was torn beyond repair. The incision
was closed after the manner of Brown (1953). In several
of the larger dogs the lip of the greater trochanter

was cut off with an osteotome and mallet upon entry and

30

Figure 5. Lateral views of a central ace-
tabular fracture showing method Of reduc-

tion with the towel clamp in place and the
direction of the bone screw being inserted

across the fracture line.

31

 

Figure 5.

32

wired back in place with two interrupted sutures of
stainless steel wire on closure after Gorman's tech-
nique (1955). This was an attempt to Obtain a firmer
attachment of the middle gluteal muscle.

Exceptions to this general regimen were as follows:
(1) in Dog~Me4, four months old, the pelvic bones were
not strong enough to keep the towel clamp prongs from
tearing through the bone when clamped shut, so a Stein-
man pin was driven across the fracture site and the end
cut next to the ilium; (2) in Dog M—ll, a stainless
steel screw was used for fixation of a fractured greater
trochanter; (3) in Dog K-26, an intramedullary pin was
used to fix a femoral neck fracture.

Ventro-dorsal and lateral radiographs were taken
at the completion Of each Operation.

.Aftercare consisted of cage rest and the prevention
of weight—bearing of the left leg by a single sling of
adhesive tape. The sling was removed after two to three
days or, in cases of femoral neck fracture, after ten
days. At the time the cages were cleaned, the dogs were
allowed to romp together. This was the only exercise they

received.

33

E. Method of Evaluation

The dogs were clinically evaluated after periods
ranging from sixty-eight days to one hundred forty days
and then euthanasia was performed with sodium pentObar-
bital. The evaluation consisted of Observation of the
animal when standing, at a walk, and at a run. The
functional range of the coxofemoral joint was deter-
mined by manual manipulation and the fracture callus
was palpated per rectum. Ventro-dorsal and lateral
radiographs were taken at the time of euthanasia.

A necropsy was performed on each dog. The pelves
and femora of the animals were saved and cleaned of
tissue after soaking in hot water. Thirty-five-
millimeter colored slides were made from photographs of
the live animal at the time of evaluation and later of
the mascerated pelves and femora. Line drawings were
traced from ventro-dorsal radiographs of the pelves
showing the original fractures, fixations and final

radiographic results.

Chapter IV

Results

See Tables I, II and III; Figures 6, 7, 8, and 9.

In every case of pelvic fracture produced in this
study, the left and right pubic bones were broken.

Rupture of the urinary bladder was conspicuously
absent from the dogs in which pelvic fractures were
created experimentally. This was also true in the sur-
vey of fifty cases of naturally acquired pelvic fractures
made by the author at Michigan State University.

All the dogs in the experiment showed moderate to
marked fibrosis of the coxofemoral joint capsule.
Fluid was present within the joint whether the joint
capsule was sutured at the time of reduction or was

torn beyond repair.

34

35

 

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Dog
Number

M-lO

M-ll

M-20

Mr22

K-20

K-23

K-25

K-26

K-27

37

Table III. Description of healed fracture

sites of macerated

pelves and femora

Massive connective tissue proliferation around

coxofemoral joint.
with mal-position

Femoral neck fracture healed
of head.

Inner bony table of acetabulum gone. Central and

marginal erosions

Connective tissue
right acetabula.

of femoral head.

proliferation around left and
Bony pelvis essentially normal.

Bony pelvis essentially normal.

Screw was loose.

Moderate fibrosis around joint.

Pelvic canal narrowed moderately.

Acetabulum collapsed with roughened articular sur-
face. .Necrosis of femoral neck. Femoral head
healed in mal—position on proximal femoral shaft.

Left and right acetabula gave the same appearance.
.Fibrosis of both coxofemoral joints. Pelvic canal

narrowed one—half

normal size.

Some dorsal displacement of ischial fragment.
Some bony proliferation at edge of femoral head.

Bony pelvis essentially normal. Femoral neck

fracture healed.
lum gone.

Inner bony table of acetabu-

Loss of crescent shape of acetabulum. Roughened

articular surface.
head and neck.

Aseptic necrosis of femoral

‘T -:. -.-:--- 7‘13:

_.-.

_J_— __

38

Figure 6. Photograph of line drawings made
from ventro-dorsal radiographs showing the
dog number, and from left to right, the
original fracture, immediate postoperative
appearance and the final radiographic result

at the time of euthanasia.

40

Figure 7. Photograph of line drawings made from
ventro-dorsal radiographs showing the dog number
and from left to right, the original fracture,

immediate postoperative appearance and the final

radiographic result at time of euthanasia.

 

 

41

 

Figure 7.

42

Figure 8. Dog K-26, a favorable example. The
ventrO-dorsal View shows the restoration of
normal pelvic structure and minimal bony callus
formation at the acetabular and femoral neck
fracture sites. The lateral view shows a normal

crescent-shaped acetabulum.

43

 

 

 

Figure 8.

44

Figure 9. Dog K-27, an unfavorable example.
The ventro-dorsal view shows bony proliferation
of the fracture sites and avascular necrosis of
the femoral head. The lateral View shows bone

proliferation around the acetabulum.

45

 

Figure 9.

Chapter V

Discussion

Although results were promising, it is felt that
the method described is not the final answer to severe
acetabular fracture in the dog. Good results can be an-
ticipated in cases of unilateral central acetabular
fracture with medial displacement of the femoral head if
the ilial shaft and body of the ischium are intact on the
affected side; if the dog is six months Old or older
and is a cocker-sized dog or larger and if the circula-
tion to the femoral head is not severly disrupted. Poor
results can be anticipated (1) if the acetabular fracture
is bilateral and both sides are operated at one time;
(2) if either ilial shaft or ischial body is fractured,
thus preventing coxofemoral stability; or (3) if the an—
imal is very young, since the towel clamps will tear
through immature bones. It is difficult to Obtain satis-
factory exposure and reduction in toy dogs, Obese animals
or chondrodystrophic breeds.

Fractures of the dorsal weight-bearing surface of
the acetabular crescent and fractures of the ilial aspect
of the acetabulum are most readily managed by the method

described. Fractures of the posterior lip of the aceta-

46

47

bulum are most difficult to reduce and fix because of the
presence of the internal obturator muscle and ischial
curvature at this point.

Investigation and modification of the Roger Anderson
splint was not pursued because of its cumbersome nature,
difficulty of sterilization and impracticality for use
by practitioners.

The turnbuckle assembly, although not mechanically
suited for the management of acetabular fractures, may
be of some help in reducing overriding fractures of the
ilial shaft or in sacroiliac separations.

The author became disenchanted with external fix-
ation using Kirschner and Tower equipment because of
the amount of time necessary to Obtain an anatomical
reduction, the increased necessity of attentive after-
care and the fact that the pins, even if well placed,
soon lost their stabilizing influence when pressure
necrosis of the pin-holes loosened the assemblies.

Bone screws are better adapted to the fixation of pelvic
fractures than bone pins because of greater grasping
power and less of a tendency to loosen.

Bone plates are difficult to shape to the irregular

48

surface of the bony pelvis. An inert metal strip which
could be molded to the contour of the pelvis across frac-
ture sites and secured with bone screws would be useful
in the open reduction of certain pelvic fractures.

Simple hand corkscrews when screwed into cancellous
bone provide an effective means Of manipulating bone frag-
ments. This should be particularly effective in large
animal orthopedics where fragments are large and cannot
be easily moved with bone grasping forceps.

The author prefers the dorsal surgical approach to
the coxofemoral joint as described by Brown because of
the adequate exposure of the area, minimal hemorrhage and
the versatility the approach offers for treatment of a
variety of conditions.

The dorsal approach to the ilium described by Cawley
and Archibald (1955) is only practical when used for frac-
tures very high on the ilial shaft. The ventral approach
of Rieger (1956) is limited to rather rare fractures of
the anteroventral acetabular lip and wiring of these
fragments does not result in effective stability. The
perineal approach described in Chapter III may be of

some value in the pinning of the ischial body but exposure

49

of the ischium is Obscured by the internal obturator
muscle.

The pelvis is well protected by muscle, fat and
fascia. This prObably accounts for the tremendous force,
such as is experienced in automObile accidents, required
to disrupt the pelvis and the fact that pelvic fractures
are seldom compound. The pelvic musculature is prObably
in a spastic state following fracture and this could be
the reason for the lack of crepitus in these cases.
Muscle spasm imparts a relative stability to bone frag-
ments and this stability prObably accounts for much of the
success following conservative treatment of pelvic frac-
tures. The author suggests the employment of rectal
palpation of the pelvis as a routine procedure in all
automObile accident cases. Since the pubic bones are
the weakest portion of the bony pelvis and are usually
broken when pelvic displacement occurs, rectal palpa-
tion of the pelvis particularly the pubes can quickly
determine the presence or absence of pelvic disruption.

It is the author's opinion that further research
in the area of open reduction and internal fixation of

pelvic fractures in the dog would be rewarding. Further

50

use and development of bone screws, small threaded bone
pins and modification of the Hagie* and Knowles* pins

would prObably be the most fruitful approach.

 

7—“‘
Orthopedic Equipment Co., Bourbon, Indiana

Chapter VI

Conclusions

1. Severe impact, such as being struck by an auto-
mObile, is necessary to fracture the canine bony pelvis.
When enough force is applied to the pelvis to cause dis-
ruption, the pubic bones are nearly always fractured.
Pubic fractures can be ascertained by rectal palpation.
2. The extent of a pelvic fracture cannot be deter-
mined by Observation of a dog's ability to stand and walk.
3. Both ventro-dorsal and lateral radiographs are ne-
cessary for accurate evaluation of pelvic fractures and
for the choice of treatment method.

4. Some advantages of internal fixation of severe
pelvic fractures as opposed to external fixation are:
(a) more precise anatomical reduction, (b) lower cost

of equipment and (c) ease of postoperative care.

5. Bone screws or screwelike pins have a greater use—
fulness in the fixation of pelvic fractures than do
non-threaded bone pins.

6. Rather severe unilateral fractures of the dorsal
acetabular crescent in the dog can be repaired by open
reduction and internal fixation. The fracture site is

exposed by Brown's (1953) dorsal surgical approach to

51

52

the coxofemoral joint; the fracture is reduced mechan-
ically and fixed with a single bone screw. This method
seems to be limited to unilateral fractures of the dorsal
and anterodorsal acetabular crescent. Dorso-ventral and
lateral radiographs of pelvic fractures should be care-
fully studied with a skeletal pelvis in hand to determine
whether or not this method of treatment is applicable.

7. Avascular necrosis of the femoral head because of
disruption of its blood supply may be encountered in

this type of fracture or after this method of treatment.
A moderate to marked fibrosis of the coxofemoral joint

capsule may also be expected as a postoperative result.

References

Archibald, J., Brown, N.M., Nasti, E. and Medway, Wm.:
Open Reduction for Correction of Coxofemoral Dislo-
cations. Vet. Med., 48, (1953): 273-275.

Brinker, W.O.: Fractures of the Pelvis. Canine Surgery.
4th ed. American Veterinary Publications, Inc.,
Santa Barbara, California, (1959).

Brown, R.E.: A Surgical Approach to the Coxofemoral
Joint of Dogs. No. Am. Vet., 34, (1953): 420-422.

Cawley, A.J. and Archibald, J.: Intramedullary Pinning
of Pelvic Fractures. I. The Ilium. NO. Am. Vet.,
36, (1955): 747-751.

Colonna, P.C.: Regional Orthopedic Surgery. W;B.
Saunders, Co., Philadelphia and London, (1950).

Conway, F.M.: Fractures of the Pelvis. Am. J. Surgery,
30, (1935): 69-82.

Dorland. W;A.: The American Illustrated Medical Dic-
tionary. W.B. Saunders, Co. Philadelphia and London,
(1951).

Ehmer. E.E.: Special Casts for the Treatment of Pelvic
and Femoral Fractures and Coxofemoral Luxations. No.
Am. Vet., 15, (1934): 31-35.

Elliott. R.E.: Central Fractures of the Acetabulum.
Clinical Orthopaedics. No. 7. J.B. Lippincott, Co.,
Philadelphia and Montreal, (1956).

Gorman, H.A.: Thesis for M.S. Degree, Ohio State
University, (1955).

Henley, C.A.: Comminuted Fracture of the Femoral Neck
and the Pelvis of a Dog. J.A.V.M.A., 127, (1955):
47-48.

Johnson, W.: A new Method of Pelvic Fixation. Ill.

Med. J., 112, (1957): 59-60.

53

54

Key, J.A. and Conwell. H.E.: Fractures, Dislocations and
Sprains. 3rd ed. C.V. Mosby, Co., St. Louis, (1942).

Knight. R.A. and Smith, H.: Central Fractures of the
Acetabulum. J. Bone & Joint Surg., 40-A, (1958): 1-16.

Leonard, E.P.: Orthopedic Surgery of the Dog and Cat.
W.B. Saunders, Co., Philadelphia and London, (1960).

Levine. M.A.: A treatment of Central Fractures of the
Acetabulum. J. Bone & Joint Surg., 25, (1943):
902-906.

Miller, M.E.: Guide to the Dissection of the Dog, 2nd ed.
Ithaca, New York, (1948)

Nowland, L. and Conwell, H.E.: Fractures of the Pelvis.
Surg. Gynec. Obst., 56, (1933): 522-525.

Olsen, M.L.: Multiple Fractures of the Pelvis. Canine
Surgery. 4th ed. American Veterinary Publications, Inc.,
Santa Barbara, California, (1959).

Rieger, H.: Frakturen in die Pfanne des Hundes und ihre
Operative Behandlung. Berlin Manh. Tier. WOch.,
18, (1956): 360-362.

Rose, T.F.: Disruption of the Pelvis. J. Bone & Joint
Surg., 33-B, (1951): 112-113.

Skey. P.C.: Operative Surgery. Blanchard and Lea,
Philadelphia, (1851).

Smith, L.D.: Hip Fractures. J. Bone & Joint Surg.,
35-A, (1953): 367-383.

Speed, J.S. and Knight, R.A.: Campbell's Operative
Orthopaedics, Vol. I. C.V. MOSby, CO., St. Louis,
(1956).

Stewart, J.J. and Milford, L.W.: Fracture-dislocation of
the Hip. J. Bone & Joint Surg., 36—A, (1954): 315-341.

Watson-Jones, R.: Fractures and Joint Injuries. Vol. 2,
4th ed. Williams and Wilkins, Co., Baltimore, (1955).

Whiston, G.: Internal Fixation for Fractures and Dislo—
cations of the Pelvis. J. Bone & Joint Surg., 35-A,
(1953): 701-706.

OCT 2 3 ’63

 

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