A. Krackow, M.D.
surgical treatment of severe preoperative fixed deformity at total
knee arthroplasty involves the appreciation of several basic principles.
First, and most obvious, is the fact that fixed deformity means
that the soft tissues about the knee are unbalanced. A relative
contracture exists at the inner or concave side of the deformity,
while a comparative "excess" in the soft tissue envelope exists
on the opposite, convex side. If soft tissue balance is to result
where major deformity existed, it will have to be achieved by
surgical adjustment of the soft tissues themselves. Since the
balance was not present preoperatively, if it is to exist postoperatively,
it must be created intraoperatively. Soft tissue balancing per
se will not be achieved by bone resection, and the surgeon must
remember that the ultimate goal at surgery is to establish correct
alignment of the tibia with respect to the femur and to create
concurrently a balance of the tension in the surrounding capsular
correct bone resection recreates the proper alignment of the femur
to the tibia, when performed alone, it will not have addressed
the soft tissue imbalance. Bone resection does, however, establish
the orientation of the prosthetic components with respect to the
axes of the femur and tibia. Because of this, the surgeon is limited
to orienting his distal femoral and proximal tibial cuts so that
the resulting prosthetic joint will be appropriately aligned.
Such proper alignment is independent of soft tissue balancing
considerations and, rather, is dependent upon parameters of individual
authors have accepted the following as constituting proper alignment
at total knee arthroplasty:
prosthetic joint shall be centered on the mechanical axis of the
lower extremity and shall be horizontal to the ground in anatomic
two-legged stance (Fig. 11.1.1).
knee and lower extremity alignment are symbolized here. A
horizontal joint line exists with the knee joint being centered
on the mechanical axis. Both lower extremities are adducted
so that the feet are adjacent to the midline. A line from
the center of the femoral head to the center of the knee passes
through to the center of the ankle. A fixed trapezoid is formed
by connecting the centers of the femoral heads, drawing the
mechanical axes and connecting the centers of the ankles.
definition of mechanical axis is standard, i.e., a line connecting
the center of the femoral head with the center of the ankle.
two-legged stance is that position assumed by a subject standing
with knees extended and both lower extremities adducted so that
the feet approach the midline. This orientation of an individual
lower extremity is also very close to the position assumed during
mid stance phase of normal gait.
a prosthetic joint is to be well aligned, then the orientation
of the distal femoral cut to the shaft of the femur and the orientation
of the proximal tibial cut to the shaft of the tibia are predetermined
for a given patient. This fact can be appreciated by first considering
a situation wherein the distal femoral and proximal tibial cuts
are properly oriented and the knee prosthesis is properly aligned
in anatomic two legged stance. If, instead, a slightly different
distal femoral cut had been made, one which has a greater valgus
angulation with respect to the shaft of the femur, then the center
of the femoral head would come to lie lateral to a line coming
up from the center of the ankle through the center of the knee
(Fig. 11.1.2). In this instance, if a mechanical axis line were
constructed from the center of the femoral head to the center
of the ankle, the mid point of the knee would lie medial to that
result of an improper excessive valgus cut is symbolized.
A distal femoral cut made in excessive valgus results in lateral
positioning of the femoral head when the cut femur and tibia
are brought together. Here a line drawn from the center of
the femoral head to the center of the ankle passes lateral
to the center of the knee.
if in a second situation the distal femoral cut were made in relative
varus, the femoral head would wind up medial to the knee, or alternately,
the knee would lie outside the mechanical axis (Fig. 11.1.3).
a proper femoral cut, an improper proximal tibial cut would similarly
displace the knee from the desired position on the mechanical
axis (Fig. 11.1.4).
an inappropriate varus distal femoral cut, the femoral head
lies medial, and a line from the center of the femoral head
to the ankle passes medial to the knee.
orientation of the proximal transverse tibial cut similarly
creates malalignment by displacing the center of the knee
from the mechanical axis when the cut surfaces of the femur
and tibia are opposed.
it is true that an incorrect femoral cut could be balanced by
an equally incorrect tibial cut made in the opposite sense, and
that a joint centered on the mechanical axis would result, the
prosthetic joint line would, however, no longer be horizontal.
If anatomic two-legged stance were maintained, the joint line
would assume an undesirable obliquity (Fig.1 1.1.5).
fact that the inclinations of the distal femoral and proximal
tibial cuts are fixed and determined individually according to
body build may be appreciated from an additional viewpoint. Assuming
that deformity has been corrected and that the extremities have
been properly "straightened," the lines connecting the centers
of the femoral heads, each femoral head to each respective ankle,
and last, the centers of the ankles, form a trapezoid whose size
and shape is unique for the patient (Fig. 11.1.6). The construction
of such a trapezoid with the subject positioned in anatomic stance
determines the inclination of that patients mechanical axes
with the vertical, usually 2.53°. Since the tibial shaft
axis is coincident with the tibial segment of the mechanical axis,
the orientation of the tibial cut with respect to the tibia itself
must be the same as the orientation of the mechanical axis with
a horizontal line.
11.1.5. An improper femoral cut has been balanced
by an equally improper and complementary tibial cut. The prosthetic
joint line remains centered on the mechanical axis, but it
becomes tilted with respect to the horizontal.
four-sided figure is formed by connecting the centers of the
patient's femoral heads and the centers of his ankles, FF'A'A.
Assuming that a patient has essentially equal extremity lengths
and assuming that his preexisting valgus or varus deformities
have been corrected bilaterally, this four-sided figure becomes
an isosceles trapezoid. The angular orientation of the mechanical
axes FA and F'A', therefore, depends upon the distance between
the patient's femoral heads, his ankles, and the respective
lengths of his femur and tibia. ø denotes the angulation
measured between the mechanical axis and the veritical. ß
denotes the angle formed between the mechanical axis and the
shaft of the femur. ø is generally noted to be between
2.5 and 3°. ß ranges between 4° and 8°.
ø depends upon the overall form of the trapezoid. ß
depends upon the patient's femur. To achieve a horizontal
joint line with the patient standing in anatomic position,
the tibial cut must be made at an angle of ø plus ß.
As the form of this trapezoid is dependent upon body build,
and the angles ø and ß are depenndent upon the
trapezoid and the structure of the femur, it follows that
the proper angles for resection of the distal femur and proximal
tibia are solely a function of body build.
discussed in Chapter 4, regarding instrumentation, the inclination
of the femoral cut relative to the vertical and the shaft of the
femur is a combination of two angles; first the mechanical axis,
and second the angle between this mechanical axis and the femoral
shaft itself. This second angle depends solely upon the lengths
of the femur and femoral neck, and the amount
of femoral anteversion. It is also, therefore fixed
for a given patient (Fig. 11.1.6). Thus, the relative inclination
of the distal femoral cut to the vertical, and the orientation
of the proximal tibial cut, also to the vertical, once realignment
has been established, will be depended upon: the distance between
the patients femoral heads, the distance between the centers
of his ankles, the lengths of his femur and tibia, and the size
of the angle between his femoral shaft and the femoral portion
of his mechanical axis.
of these are factors of bone structure and body build, quite independent
of the degree or nature of any preexisting deformity.
the orientation of distal femoral and proximal tibial cuts is
fixed, the surgeon has some choice as to how much distal
femur and proximal tibia may be removed, that is the depth of
these cuts. Having determined the proper orientation of these
cuts by preoperative planning, the surgeon must address the contracture
or laxity in the surrounding soft tissue sleeve by either surgical
release, soft tissue advancement, some combination of these two,
or by performing deeper bone cuts and accepting some residual
instability, generally from the convex side of the deformity.
of these four approaches the surgeon chooses to use, singly or
in combination, will depend upon many individual considerations
for each specific case. It must be remembered that this chapter
addresses severe, fixed preoperative deformity wherein
some specific action will be necessary if correct alignment and
adequate stability are to be established. Furthermore, it must
be understood that the authors have striven to address these problems
and to use prostheses without rigid constraint in most severe
cases because of the predictable, unsatisfactory results with
more constrained units. Certainly, the use of hinges and other
constrained devices would simplify such cases. However, for these
patients, such simplification comes at too high a price in terms
of component loosening, if they are to resume any reasonable activity
authors of the subsections for this chapter accept the proposition
that for most patients with severe deformity. TOTAL RECONSTRUCTION
of the knee joint rather than simple replacement of surfaces is
both desirable and achievable. When long-term prosthesis survival
and the prospects for further revision and surgery are considered,
the additional operative planning and surgical effort required
by the relatively unconstrained prosthesis are deemed worthwhile
for the vast majority of these patients.
Fixed Valgus Deformity
S. Hungerford, M.D., and Dennis W. Lennox, M.D.
valgus deformity is more likely to require special surgical techniques
than are other deformities. There are several reasons for this.
First, the principal lateral stabilizers of the knee are muscles:
the popliteus, the tensor fascia lata and the biceps femoris.
This means that deformity is more likely to become fixed at an
early stage. Second, more severe valgus deformity or deformity
of long standing is likely to be associated with attenuation of
medial capsular stabilizers. Because the principal medial stabilizers
are not attached to muscles, residual static medial instability
is likely to create functional instability. For these reasons,
fixed valgus deformity is one of the more difficult problems to
be addressed at total knee arthroplasty.
with other fixed deformities, the goal is to appropriately align
the lower extremity and properly position the individual prosthetic
components. The order of cuts does not differ from the standard
sequence detailed in Chapter 4. However, since there is a basic
ligamentous imbalance, this will usually have to be addressed
as an independent problem. In varus deformity, ligamentous imbalance
may be only a function of lost bone stock. If that is the case,
restoring alignment through replacement of lost bone with the
prosthesis will automatically restore stability even with severe
varus deformity. This may not always be the case, but most varus
deformities fit within this concept. Valgus deformities become
a problem at a much earlier stage, or lesser degree of deformity.
TISSUE STABILIZERS OF THE LATERAL ASPECT OF THE KNEE
soft tissue stability of the lateral knee arises from four musculotendinous
units: the iliotibial tract, the biceps femoris, the popliteus
and the lateral head of the gastrocnemius. Additional stability
is afforded by the posterolateral capsule-arcuate complex and
the lateral collateral ligament. The anatomy of this area is comprehensively
reviewed in Chapter 1. The predilection
for valgus deformity to become fixed may reflect the observation
that, of the six lateral stabilizers of the knee, four are musculotendinous
FIXED VALGUS DEFORMITY
deformities can best be understood by dividing them into two types,
depending on medial stability. In Type I valgus deformity
the elements include loss of lateral bone stock, shortened, tight
lateral soft tissue components, and stable anatomically
intact medial stabilizers (Fig. 11.2.1). In Type II valgus
deformity, the medial
stabilizing structures have been stretched out, allowing widening
of the medial joint space (Fig. 11.2.2). Although most Type II
deformities will be identified on weight-bearing films, not all
will be so shown. Often the patient will not be putting significant
weight on the affected leg or will be bracing one knee against
the other when standing on both feet. If one suspects medial instability
on the basis of clinical findings, and it is not shown radiologically,
a stress film should be obtained.
11.2.1. Type I valgus deformity with lateral compartment
bone loss, tight lateral soft tissue elements, but anatomically
intact medial stabilizers.
11.2.2. Type II valgus deformity with all of the
features of Type I plus medial soft tissue incompetence.
MANAGEMENT OF TYPE I FIXED VALGUS DEFORMITY
correction of Type I valgus deformity is accomplished by lateral
soft tissue release. This release alone is sufficient to allow
appropriate alignment and stability of the limb since the medial
stabilizers are competent. The surgical sequence for Type I deformity
follows the standard technique through the exposure and the distal,
anterior and posterior femoral cuts.
to inserting jig IV and extending the knee, the lateral border
of the tibia should be thoroughly inspected for the presence of
marginal osteophytes. Occasionally, removal of a large lateral
tibial osteophyte may obviate the need for lateral release. Loose
bodies in the posterior recess must be removed as well as posterior
and lateral osteophytes on the femur. These may tent
capsular structures preventing correction of deformity.
the spacer-tensor jig in place, the leg is extended. If the center
of the ankle joint can be brought under the tip of the tibial
alignment pin, the fixed deformity has already been corrected,
and one can proceed utilizing standard technique. However, it
is at this point that fixed deformity is demonstrated by the fact
that the ankle cannot be brought underneath the tip of
the alignment pin (Fig. 11.2.3). It is also at this point that
Type I and Type IV deformities are differentiated. With the No.
II jig in place and the lateral soft tissue sleeve distracted
by expansion of the expandable arm, the medial side will be stable
in Type I deformity and unstable in Type II deformity.
lateral structures which may require release are depicted in Figure
11.2.4. In general the sequence of release would be: 1) iliotibial
tract, 2) posterolateral capsule, 3) lateral collateral ligament,
4) popliteus tendon, 5) biceps femoris tendon, and 6) lateral
head of gastrocnemius. This sequence is proposed only as a basic
plan to guide soft tissue release. The structures released early
in the sequence are those which are most commonly responsible
for deformity and which, on release or lengthening, are most likely
to allow correction. The minimum amount is released which will
allow correction of the deformity.
11.2.3. With the spacer-tensor jig in place after
the femoral bone cuts have been made, the center of the ankle
cannot be brought underneath the tip of the tibial alignment
11.2.4. Anatomy and levels of release and/or Z-plasty
of structures involved in fixation of lateral deformity.
Just as each total knee arthroplasty is somewhat different, so
too may the elements contributing to valgus deformity vary from
individual to individual. Thus, preoperative and intraoperative
palpation to determine which structures are responsible for lateral
tightness should be utilized to guide soft tissue release rather
than to adhere rigidly to a sequence of releases predetermined
without regard to the particular knee under consideration. There
is no substitute for intelligent intraoperative decision making.
Z-plasty lengthening of lateral stabilizers is recommended over
simple transection since some stability is afforded by repair.
In the case of the musculotendinous units which afford dynamic
stability, a lengthening procedure with repair seems preferable
to tenotomy, particularly in the case of the strong iliotibial
band which is a primary dynamic stabilizer of the lateral side
of the joint.
OF LATERAL SOFT TISSUE RELEASE
soft tissue release laterally includes elevation of soft tissue
from the lateral tibial plateau. If required, a next step will
almost always include a Z-plasty with lengthening and subsequent
repair of the iliotibial tract. This is performed near the insertion
of the iliotibial tract without an additional incision. The iliotibial
tract is palpated with the leg in full extension and the extensor
mechanism everted to the lateral side. The anterior border of
the tract is separated from the lateral retinaculum with which
it blends. This accomplishes a lateral patellar release at the
same time. Both the medial and lateral aspects of the iliotibial
tract are then carefully isolated, and under direct vision the
Z-plasty lengthening is performed. Correction should be tested
by reinserting the spacertensor jig IV and extending the leg before
proceeding to additional releases.
release of the iliotibial tract is insufficient to allow correct
limb alignment, then other structures to be released or lengthened
in sequence include the posterolateral capsule, popliteus tendon,
lateral collateral ligament, biceps femoris tendon and lateral
head of the gastrocnemius muscle. To diminish the risk of damage
to the peroneal nerve by excessive tension, a supplementary posterolateral
incision is recommended when the lateral head of the gastrocnemius
muscle and the biceps femoris tendon require release and Z-plasty.
Decompression of the peroneal nerve should be performed as needed
to avoid excessive tension. Proximal fibulectomy is one method
to provide decompression of the peroneal nerve in severe valgus
deformity correction but this is only rarely indicated.
MANAGEMENT OF TYPE II VALGUS DEFORMITY
are two possible ways to deal with this severe form of valgus
deformity to achieve both correction of deformity and stability.
In the first case lateral release, sufficient to correct the deformity,
is performed prior to making the proximal tibial cut. Although
this will align the limb, the knee will not be stable medially.
To produce stability, a thick tibial plateau will have to be inserted
to compensate for medial laxity. This, however, requires additional
lateral release and results in lengthening the leg through the
knee. Simply correcting the deformity puts the peroneal nerve
at risk. Lengthening the leg through the knee potentiates that
risk. For extreme cases of medial instability, such an approach
is virtually impossible. The case depicted in Figure 11.2.5 would
require 15 mm of prosthesis just to take up medial soft tissue
slack, in addition to any bone resected to obtain a flat proximal
tibial cut. Even for less severe cases of Type II deformity, the
insertion of an excessively thick tibial component separates the
femoral and tibial attachments of the posterior cruciate ligament,
causing it to be prematurely and excessively tight in flexion.
valgus deformity with traumatic medial soft tissue instability.
It is impractical to provide medial soft tissue stability
through insertion of a thick tibial component.
these reasons, we prefer to produce stability in Type II deformity
by medial soft tissue advancement. For moderate Type II deformity
a limited lateral release, usually restricted to a Z-plasty lengthening
of the iliotibial tract, is performed to allow alignment of the
lower extremity prior to cutting the proximal tibia. The medial
structures are advanced to produce stability after the prosthesis
is implanted (see technique below).
more severe forms of Type II deformity with extensive lateral
contracture, the magnitude of the lateral release required can
be diminished by proceeding first with a modest femoral shortening.
Four millimeters of additional femoral shortening can be easily
and quickly carried out and produces a significant decompressive
effect on the lateral side. If one is already committed to a medial
advancement, the additional medial instability which this additional
femoral resection will produce is of no consequence. If it would
not otherwise be necessary to effect a medial advancement, femoral
shortening should not be employed. Thus, femoral shortening is
contraindicated in Type I valgus deformity. If when the IA and
IB jigs are in place in proper alignment, it can be seen that
no bone will be removed from the lateral side, a few millimeters
of the distal surface of the medial condyle can be removed with
an oscillating saw. The IA and IB jigs are then repositioned and
a femoral shortening will be automatically effected. If the need
for femoral shortening is seen only after the spacer-tensor jig
shows the magnitude and type of deformity, the following special
technique is carried out.
OF FEMORAL SHORTENING
needed, the distal femur can safely be removed to the level of
the collateral ligaments. The distal femoral cutting jig, IA,
is reinserted into
the central anchoring hole, and a 3/16" drill pin is positioned
laterally across the distal femur and acts as a spacer between
the bone and jig (Fig. 11.2.6). Next, the distal femoral cutting
jig, IB, is inserted into the IA jig and fixed with two 1/8" drill
pins. Varus-valgus and flexion-extension alignment are then rechecked
with the alignment guide. The assembled jigs IA and IB leads to
the removal of 9 mm of distal femur when jig IA is flush against
the distal femur. Therefore, by using the 3/16" drill pin (5 mm)
to hold jig IA away from the initial cut surface, only an additional
4 mm of distal femur will be removed. A thicker interposing spacer
will lead to
a correspondingly thinner additional resection and vice versa.
Assuming that, after this additional resection, full extension
and proper tibial axial alignment are possible, the standard procedure
for fixing in place the transverse tibial cutting jig V is followed.
After additional femoral resection, it will be necessary to reposition
jig III and recut the anterior femur to accommodate the femoral
the 3/16" drill as a spacer between the face of jig IA
and the initial distal femoral cut prior to relocking jib
IB in place to affect femoral shortening.
TECHNIQUE FOR FEMORAL SHORTENING
those who have the revision cutting block accessory to the Universal
total knee instruments, this can also be used for recutting the
distal femur. The details of the revision cutting block and its
use are extensively presented in Chapter 19. Since this block
can be precisely aligned with the original distal femoral cut,
this avoids the need for additional realignment before recutting
the distal femur (Fig. 11.2.7). Also, since jig V slides proximally
or distally on the anterior projection of the revision block,
it can be positioned to remove a precisely measured amount
of distal femur, of virtually any desired thickness.
(A) and lateral (B) vies of the revision cutting
block and jig V in position for carrying out femoral shortening.
THE TIBIAL CUT
AND TRIAL REDUCTION
the axial alignment of the tibia can be obtained, the standard
technique for removing the proximal tibia is followed. If it is
necessary to make a deeper tibial cut because of lateral bone
loss, care must be taken to preserve the tibial attachment of
the posterior cruciate ligament. Once the cuts have been made,
a trial reduction is carried out with the patella resurfaced and
the quadriceps mechanism reduced. Varus-valgus and anterior-posterior
stability are tested in full extension and at points throughout
the range of movement. A slight amount of medial instability
is well tolerated if the deformity has been fully corrected.
Significant medial instability, however, must be corrected.
If the medial instability at this point is only moderate, it may
be possible to correct it by simply inserting the next size tibial
spacer. Care should be taken to be certain that this does not
excessively tense the posterior cruciate ligament, resulting in
a block to flexion. An additional minimal lateral release may
be necessary to allow insertion of the next thicker tibial component
to take up minimal or moderate medial slack. Medial soft tissue
advancement will be necessary for significant medial instability.
OF MEDIAL SOFT TISSUE ADVANCEMENT
advancement is required for severe (Type II) valgus deformity.
The customary skin incision must be extended distally to expose
the pes anserinus tendons. The proximal margin of the pes anserinus
insertion is identified and a superficial incision is made along
the course of this upper border so that the pea group may be retracted
distally. Flexion of the knee relaxes the pes group and facilitates
the surgery (Fig. 11.2.8). The initial capsular incision is extended
further distally, and all soft tissue attached to the medial tibial
metaphysis proximal to the pea insertion are reflected posteriorly
and proximally as a flap, utilizing careful sharp dissection (Fig.
11.2.9). These tissues include the medial capsule, periosteum,
superficial medial collateral ligament, and eventually the posterior
oblique portion of the medial collateral ligament. Having elevated
this flap, the tibial attachment of the
principal medial stabilizers of the knee can be advanced to provide
proper axial physiologic balance.
11.2.8. Initial exposure of the medial capsular
structures through reflection of the proximal half of the
pes anserinus tendons.
11.2.9. Sharp dissection of the medial capsular
structures including the superficial collateral ligament as
a continuous flap.
component thickness is then selected, based upon that size which
provides lateral stability. Reattachment of the capsular-ligamentous
flap is performed only after the proper components are permanently
seated. With the knee just short of full extension and the components
held reduced, the medial flap is advanced distally to provide
medial stability and is stapled in place (Fig. 11.2.10). The staples
should fix at least the end of the superficial medial collateral
ligament and any other substantially thicker portions of the flap.
The pes group is then reapproximated and sutured in place.
advancement and staple fiation of the medial capsular structures
after the insertion of the prosthetic components.
management differs from the usual protocol in that a knee immobilizer
is worn at all times when ambulating. The immobilizer is removed
for supervised range of motion exercises. Overall management of
the patients activity must be determined by the surgeon,
who must consider the soft tissue quality, bone and ligament fixation
and the patients ability to follow instructions. Consideration
may be given to postoperative bracing, although this is a rare
P.L. A 79-year-old black woman complained of severe pain
and instability in the right knee. Walking tolerance was 1 block.
A 40° valgus deformity which was not passively correctible was
present. Marked medial instability was evident clinically and
radiologically. Roentgenograms demonstrated erosion of the lateral
femoral condyle and lateral plateau of the tibia (Fig. 11.2.11).
Numerous loose bodies were evident. Patellar subluxation was also
present. Preoperative 100-point evaluation rating was 25.
total knee replacement was performed utilizing the PCA components
and the Universal Total Knee Instruments. To bring the knee into
correct alignment, femoral shortening of 3 mm and release of the
iliotibial tract were necessary. The medial collateral ligament
and medial capsule were advanced and fixed with staples. She required
one manipulation postoperatively, but otherwise her course was
uncomplicated. Active and active-assisted range of motion exercises
were started 4 days after surgery, but she was protected with
a knee immobilizer during ambulation for 6 weeks. Follow-up at
23 months showed a well-aligned knee with stable range of motion
from 0° to 95°, unlimited walking tolerance without external support,
normal ascent and descent of stairs and, a 95-point rating on
the 100-point scale (Fig. 11.2.12).
film showing severe preoperative valgus deformity and medial
joint line opening.
standing film showing normal alignment of the lower extemity
and a horizontal joint line. The staples were used for fixing
the advanced medial capsular structures.
Case M.T. This 83-year-old white woman sustained a
distal femoral fracture treated with a blade plate 10 years prior
to admission, and subsequently suffered a tibial plateau fracture
treated with traction 5 years prior to admission. Over the several
months before presenting for this treatment, progressive deformity,
pain and instability had rendered her nonambulatory (Fig. 11.2.13).
Marked crepitation and patellar subluxation were noted on examination.
Motion was limited to 1080° of flexion. The valgus deformity
of 35° was not passively correctible, and marked instability on
the medial side was noted clinically and radiologically.
11.2.13. Preoperative standing
and lateral films demonstrate the severe deformity, lateral
compartment bone loss and medial side instability.
A total knee replacement was performed through a long medial patellar
incision. The blade plate was transected utilizing the diamond
wheel on the Midas Rex instrument, and the blade portion was removed.
To achieve alignment, the iliotibial tract required Z-plasty as
did the biceps femoris tendon, the lateral collateral ligament
and the popliteus tendon. Because the complex tibial plateau fracture
involved posterior displacement of that portion of the tibial
plateau to which the posterior cruciate ligament is attached,
Z-plasty lengthening of the posterior cruciate ligament was necessary
to achieve adequate flexion. The medial capsule and superficial
medial collateral ligament were advanced and fixed with staples.
Osteotomy of the tibial tubercle was carried out in order to facilitate
adequate exposure without a separate lateral incision. After the
lateral structures had been lengthened by Z-plasty, but before
the prosthesis was implanted, the peroneal nerve was mobilized
to be certain that it was not under stretch with the correction
of the deformity. Following this, the lateral structures were
repaired through eversion of the extensor mechanism and flexion
of the knee. All Z-plasty lengthenings of tendons were repaired
with interrupted sutures and the tibial tubercle was reattached
with oblique K-wires. Because of significant osteoporosis of the
tibial tubercle, the repair was protected with a circumferential
wire attached to a transverse bolt in the tibial crest (Fig. 11.2.14).
standing and lateral films show restoration of normal alignment
and horizontal joint line. The blade portion of the blade
plate has been removed, the medial capsular structures have
been advanced and fixed with staples, the tibial tubercle
osteotomy has been internally fixed with K-wires and the repair
has been protected by a circumferential wire attached to a
transverse bolt in the tibial crest.
patient was managed postoperatively in a splint and subsequently
transferred to a continuous passive motion machine. She achieved
90° of flexion at the time of discharge, 4 weeks postoperatively
and was independently ambulatory with a walker. At 8-month follow-up,
she had 105° of stable flexion, full extension, normal alignment,
no pain and a 5-block walking tolerance without support. The preoperative
100-point evaluation scale rating was 10 and the 8-month follow-up
rating was 90.
K.T. A 42-year-old white man complained of progressively
disabling right knee pain, valgus deformity and instability 14
years following a right lateral tibial plateau fracture and 4
years following a right lateral meniscectomy (Fig. 11.2.15). On
examination marked patellofemoral crepitus was noted. The valgus
deformity was not passively correctible, and there was marked
medial instability. Roentgenograms demonstrated lateral tibial
plateau depression with narrowing of the lateral joint space,
osteophyte formation, subluxation of the patella and 18° of valgus
deformity of the knee. A total knee replacement was carried out
using the PCA total knee system and the Universal Total Knee Instruments.
There was a large lateral plateau defect which required a bone
graft using as bone stock the medial posterior femoral condyle
which was resected in the course of making the femoral bone cuts.
This was internally fixed with three pins. This bone graft provided
a flat bed for implanting the resurfacing tibial component. It
was therefore possible to implant all three components without
methylmethacrylate. A Z-plasty lengthening of the iliotibial tract,
popliteus tendon and lateral collateral ligament was necessary
to appropriately align the lower extremity. The posterior cruciate
ligament was preserved in function throughout the range of movement.
The medial capsule and superficial medial collateral ligament
were sharply reflected from the medial tibial metaphysis, advanced
distally, stapled and reinforced with the pes anserinus tendons.
6-month follow-up, he had a well-aligned lower extremity (Fig.
11.2.16), stable range of movement from 0 to 105° of flexion,
and no pain. Roentgenograms showed continuing intimate fit of
the bone to the prosthetic components (Fig. 11.2.17).
11.2.15. Preoperative standing
films show the degree of deformity, lateral compartment bone
loss and medial compartment opening.
11.2.16. Long standing films postoperatively show
restoration of alignment and horizontal joint line.
(A) and lateral (B) fluoroscopic spot views at 6 months
follow-up show intimate fit of the bone to the prosthetic
components and evidence of incorporation of the bone graft
to the lateral tibial plateau.
fixed valgus deformity of the knee often requires special techniques
to achieve the operative goal of correction of deformity and correction
of instability throughout an adequate range of movement. The alignment
of the prosthetic component is not dependent upon the degree of
deformity and cannot be varied to accommodate deformity. Therefore,
proper positioning of the individual prosthetic components and
achieving balanced soft tissue tension throughout the range of
movement are interrelated, but nonetheless independent problems.
Soft tissue balance can be achieved through igamentous release
and/or lengthening combined with the possibility of femoral shortening
and advancement of medial capsular structures. The alternatives
available in the stepwise progression of the operative procedure
have been presented with the rationale for the stepwise decision
making which must take place at the various steps in the operative
procedure. Operative techniques for lateral ligamentous release,
femoral shortening and medial soft tissue advancement have also
been presented. Illustrative cases demonstrate the sequence of
steps to achieve satisfactory results in difficult cases.
Fixed Varus Deformity
S. Laskins, M.D.
varus deformities as seen in the arthritic patient (Fig. 11.3.1)
occur at the joint level, and may be either mobile or fixed. Mobile
deformities are correctible passively (Fig. 11.3.2), while fixed
deformities are not (Fig. 11.3.3). Many knees demonstrate features
of being both fixed and mobile; i.e., a knee may have a varusangulation
on standing x-rays of 20°, which, with stress, corrects
to 10° of varus. The degree to which a deformity is fixed
is determined by the severity of soft tissue contracture on the
medial aspect of the knee. These structures include the deep capsular
ligament, the superficial collateral ligament, the pes tendons,
the posteromedial capsule and the posterior cruciate ligament.
are no fixed rules to explain why some patients develop varus knee
deformities, others develop valgus deformities, and still others
develop one knee in valgus and one in varus (the so-called wind-swept
pattern). As a general (but not inviolate) guide, varus appears
to be more common in the short obese patient with osteoarthritis,
and somewhat less common in the tall asthenic, or rheumatoid patient
alignment of the leg as measured by the mechanical or anatomical
axes may be caused by angulation through the femoral or tibial
diaphysis (Fig. 11.3.4). Malunited fractures, or late results
of skeletal dysplasias, rather than arthritis, are usually the
etiologic causes in these cases. Roentgenograms extending from
the hip to the ankle joint must always be obtained preoperatively
lest such an angular diaphyseal deformity be inadvertently missed
while one concentrated on knee pathology (Fig. 11.3.5).
11.3.4. Varus deformity due to cartilage loss.
11.3.5. X-rays of a 65-year-old patient with an
overall varus deformity of the leg despite predominantly lateral
compartment osteoarthritis. The cause: a malunited fracture
of the tibial shaft.
are three anatomic derangements associated with a varus knee deformity
in the arthritic patient: cartilage loss, soft tissue contracture,
and bone loss. Although these will be discussed individually, many
patients manifest varus deformities on the basis of a combination
of two or all three of these factors.
loss from the medial femoral-tibial joint space is the basic abnormality
in almost every patient with an arthritic varus knee (Fig.11.3.4).
This loss causes a diminution of the "spacer height" on the medial
aspect of the joint. Varus deformity, due to cartilage loss alone,
is generally completely correctible, that is, completely mobile.
At surgery, merely restoring the joint height by an implant of
sufficient thickness suffices to correct the deformity (Fig. 11.3.6).
if only the medial femoral-tibial cartilage were lost, (Fig. 11.3.7)
unicompartmental replacement would be an effective surgical procedure
(Fig. 11.3.8). Unfortunately, results for such medial replacement
vary widely. Marmor (16) noted excellent results in only 33 of
56 patients (50%), and poor results in over 21%. He still felt,
however, that the procedure was a valuable one for general use.
It is of interest to note that in his published cases the
revealed that the preoperative varus deformity was not corrected
completely at the time of surgery. Mallory and Dolibois (14) stated
that they corrected the varus deformity using either the Marmor
or polycentric prostheses, and that over 90% of their patients
had excellent or good results. Similar, optimistic results were
reported by Scott and Santore (18). Englebrecht et al. (3), however,
noted a 22% failure rate and Insall and Walker (6) a 26% failure
rate. In our series (11), there was a 35% failure rate, the causes
of which were manifold: adverse effects of wear particles on the
lateral, unreplaced compartment, patellofemoral symptoms, recurrence
of the deformity, inadequate initial correction or overcorrection
of the deformity. Cartier and Villers (1) have attempted to overcome
the alignment problems through a series of preoperative roentgenographic
measurements (Fig. 11.3.9) which are then used as guides at surgery
to determine implant thickness and placement. Technetium-99 bone
scans may be used in a manner analogous to Coventrys (2)
use in tibial osteotomies to ascertain the condition of the lateral
tibiofemoral compartment (Fig. 11.3.10). With these types of modifications
in technique, unicompartmental replacement may again emerge as
a valid procedure. It may especially be useful in the patient
with traumatic arthritis due to a previous tibial plateau fracture,
or the patient with osteonecrosis of the medial femoral condyle.
loss from the medial femoral condyle or the medial tibial plateau
can certainly cause varus deformity in the arthritic knee (Fig.
11.3.11). This bone loss results from overload of the subchondral
bony areas. With any degree of varus deformity, there is a medial
displacement of the force resultant during the stance phase of
gait (Fig. 11.3.12) (15). The response is a thickening and buildup
of bony trabeculae in the subchondral area as predicted by Wolff
(19) and Pauwels (17). As this overload increases, this ability
to form new bone is overshadowed by the accumulation of microfractures,
and eventually there is bony collapse.
of bony loss on the tibial side may be made in the following manner.
The anatomical axis is drawn in the standard manner described
previously. A line is then drawn joining the superior outer portion
of both tibial plateaus. This transtibial line (TTL) normally
intersects the tibial portion of the anatomical axis forming an
acute angle open medially at 87° ± 3° (approximately 23°
short of a right angle) (Fig. 11.3.13). Any medial acute angle
less than this is an indication that there has been bone loss
from the proximal medial tibial plateau (Fig. 11.3.14). A line
can also be drawn connecting the most inferior portions of the
femoral condyles. This should intersect the axis of the femoral
shaft at an angle of between 7° and 11° less than a right angle,
(the smaller angle in tall patients, and larger ones in patients
with broad pelvis). Any angulation less than 7° between these
two lines indicates either actual bone loss from the medial femoral
condyle or at least that femoral condylar deformity is participating
in the production of abnormal varus.
11.3.11. Varus deformity due to bony loss from
the proximal tibia.
resultant of body forces in a varus knee falls completely
on the medial plateau.
11.3.13. The normal transitibial line. It intersects
the anatomical axis of the tibia forming an angle of 88°
11.3.14. An x-ray of a patient with medial plateau
bony loss. The transtibial line intersects the anatomical
axis of the tibia at an angle of 62°.
of bone loss on the femoral side can be accomplished by adjusting
the level of the distal femoral resection line in a manner so
that a flat surface for implant support is obtained. Obviously
one cannot resect the femur more proximal than the epicondylar
insertion of the collateral ligaments. Fortunately for the average
case, only small degrees of proximal resection are required.
of bone loss on the tibial side is correctible in at least three
Make the tibial resection cut at a lower level than normal (Fig.
11.3.15). This method is less applicable when such resection goes
well below the tubercle of Gerdy with its iliotibial band insertion.
The surgeon must recognize that such resection will cause lateral
laxity especially as the knee is brought to full extension.
Make the tibial resection cut at the normal level (just below
the joint surface) and fill in the resultant defect medially with
acrylic cement (Fig. 11.3.16). This method is applicable for smaller
degrees of bony loss and works well when the cement remains contained
within a circumferential bony bed. When, however, there has been
loss of bone extending out to and including the medial cortex,
the cement may be unsupported. The use of mesh or supporting screws,
although suggested by some surgeons, still places the cement in
an unsupported position. In these cases, the third method is applicable.
Make the tibial resection at the normal level and bone graft the
medial defect (Fig. 11.3.17A). This method is applicable to larger
degrees of bone loss when the two previous methods are not feasible.
A convenient source of autogenous bone is the posterior aspect
of the femoral condyles. Any remaining cartilage is removed from
the condylar fragment, and the bone is affixed to the depressed
tibial plateau with two counter-sunk cancellous bone screws (Fig.
11.3.17B). The screws are inserted and angled anteriorly and laterally
into the tibia. The newly formed plateau is then trimmed to the
level of the previously resected lateral tibial plateau, and a
standard or appropriate thickness tibial plateau component is
used (Fig. 11.3.17C). This method has been used for over 2 years
and in 14 cases of severe varus deformity with marked bone loss
(Fig. 1 1.3.18AC). We have not noted any increased settling
of the tibial implant nor any increase in radiolucency about the
component as compared with a similar group in which bone grafts
were not used. In this group of patients, the limb is protected
from weight bearing for approximately 12 weeks awaiting incorporation
of the bone graft.
anatomic component of varus knee deformity in the arthritic patient
is soft tissue contracture on the medial side of the knee (12).
This contracture is adaptive, following and perpetuating any varus
deformity from either cartilage loss or bony loss. The media!
structures, including the deep capsular ligament, the pes tendons,
the superficial capsular ligament, and the posteromedial capsule,
can all become contracted (Fig. 11.3.19). This contracture is
accentuated if there are any medial tibial plateau osteophytes
lifting up and tenting the medial capsular ligamentous complex.
for soft tissue contracture consists first of removing all medial
osteophytes from both the tibial plateau and the femoral condyle.
Next, the entire medial capsule and deep capsular ligament are
elevated as a half sleeve from their attachment to the proximal
tibia. The dissection should progress around the tibia posteriorly
as far as necessary to release the contracture, separating all
the structures inserting onto the metaphysis. For more severe
contracture, it may be necessary to elevate the insertion of the
superficial collateral ligament and to cross-cut or elevate the
attachment of the capsular sleeve and pes tendons distally, allowing
the entire medial sleeve to recess proximally (Fig. 11.3.20).
In these cases, resection of the posterior cruciate ligament is
frequently required for full correction of the deformity. The
capsular sleeve may be reattached to metaphyseal bone by staples
or it may be allowed to heal without specific fixation in its
new proximal position (Fig. 11.3.21). This author has not used
fixation in his series and has observed no specific problems while
others advocate reattachment of the soft tissue sleeve (5). These
patients are routinely kept in a knee splint for approximately
3 weeks to allow this healing to occur.
11.3.19. Varus deformity in a patient with soft
tissue contracture medially; this contracture is accentuated
by the prominent tibial plateau7 osteophyte tenting up and
tethering the medial structures.
11.3.20. Capsular release for soft tissue contracture
medial capsular flap is allowed to recess proximally.
For varus knees
in which there is a combination of cartilage loss, bone loss, and
soft tissue contracture, the suggested order of correction is as
of tibial plateau and femoral condylar marginal osteophytes.
of the medial capsular sleeve and, if necessary, proximal recession
of the sleeve.
of bone loss by one of the three methods described above.
for cartilage loss by varying the height of the tibial implant
SOFT TISSUE ADVANCEMENT
additional technique for the management of severe varus deformity
has been developed by Krackow (7) and employed by Krackow and
Kenna (10). This approach involves tightening the soft tissue
sleeve on the lateral side of the knee. It is emphasized that
most patients with even moderate varus deformity will not require
either the bone grafting technique or this lateral advancement.
Most patients will tolerate a small to moderate amount of lateral
laxity after total knee arthroplasty as long as good postoperative
alignment has been achieved. However, with the very severe varus
cases, these more extreme methods will be appropriate.
lateral soft tissue advancement is particularly applicable in
the following circumstances:
When, after medial soft tissue release and cementing of components,
unacceptable lateral laxity exists.
When a situation analogous to Type II valgus deformity exists.
That is, severe, longstanding varus deformity can create attenuation
of the lateral soft structures to such a degree that unrealistic
medial soft tissue release would be necessary to achieve ligamentous
balance. In these cases, lateral advancement may be considered
preferable to medial release.
When medial bone grafting seems undesirable either because the
bone stock is of questionable quality, or the patients ability
to comply with protracted partial weight bearing is uncertain.
OF LATERAL ADVANCEMENT
straight incision, slightly posterolateral along the posterior
edge of the fibular head, is made from 1 ½" above the joint line
to 2" distal to the tip of the fibular head (Fig. 11.3.22). The
peroneal nerve is identified and mobilized posterolaterally dividing
the fascial roof created by the peroneus longus muscle where the
peroneal nerve crosses the neck of the fibula. Subperiosteal dissection
completely around the distal aspect of the fibular neck is performed.
osteotomizing the fibula, an appropriately sized hole is drilled
from the tip of the fibula, in an intramedullary direction into
the proximal fibular shaft (Fig. 11.3.23). This hole is tapped
to receive an ASIF 6.5 mm cancellous screw, an ASIF 4.5 mm malleolar
screw or a Vitallium lag screw, whichever the surgeon deems most
appropriate according to the size of the fibula and the equipment
available. It is important that this fixation hole be predrilled
to assure accurate positioning of the fibular head after a segment
of fibular neck is removed.
oscillating saw is used to osteotomize the
approximately ¾" to 1" distal to the tip of the fibula (Fig. 11.3.24).
The osteotomy is made perpendicular to the fibular shaft axis.
The resulting proximal fibular piece is grasped with a clamp and
carefully dissected free from all capsular and fascial attachments
to the lateral surface of the tibia, being careful to preserve
the attachment of the biceps femoris tendon and the lateral collateral
ligament to this piece of fibula. It is necessary that complete
release from the tibia be achieved so that traction on the fibular
head is restrained by the femoral attachment of the lateral collateral
ligament. Otherwise adequate distal advancement of the lateral
ligament will not be possible.
final implantation of the femoral and tibial components, the knee
is held in reduced position at approximately 10-20 degress of
flexion. Gentle traction is placed on the fibular head which is
brought alongside the remaining fibular shaft (Fig. 11.3.25).
The amount of overlapping bone is marked and removed from the
fibular shaft with an oscillating saw. Last, the knee is flexed,
the tibia externally rotated, and the fibular head fixed with
an intramedullary lag screw (Figs. 11.3.26 and 11.3.27). After
wound closure the knee is protected in a splint unless a continuous
passive motion device is employed. Range of motion, both active
and gentle assisted passive motion, is begun in physical therapy
at the standard time. Weight bearing during gait is performed
for 6 weeks with a knee immobilizer in place, otherwise, postoperative
management is identical to other cases of total knee arthroplasty.
procedure described provides good lateral stability with quite
secure fixation of the advanced lateral soft tissues. Problems
at the fibular osteotomy regarding the bone or peroneal nerve
have not been observed in a small series of patients. Studies
by Krackow and Brooks (8,9) demonstrate the safety of distal advancement
of a lax collateral ligament with regard to maintenance of proper
ligament tension throughout the motion cycle. Furthermore, the
dissection employed and the management of the fibular head and
lateral stabilizers are not too different from what one does during
high tibial osteotomy for varus deformity.
varus deformity is best managed by simple soft tissue release
with osteophyte removal, major medical ligamentous revision, medial
bone grafting, or lateral ligament advancement will depend upon
many factors dependent upon the particular case at hand.
one method that should not be used in correcting a varus deformity
is that in which the resection plane of the proximal tibia is
angulated. With such an approach, one or both of the following
will occur. The prosthetic joint line will not be parallel to
the floor in normal stance and/or residual varus deformity will
be present. Asymmetrical loading will occur and premature loosening
and increased cold flow can be expected. Protocols which suggest
or require such resection and which do not suggest correction
of soft tissue contractures when present should be viewed with
A. Krackow, M.D.
previous sections addressing the handling of fixed varus and fixed
valgus deformities have introduced some of the basic problems inherent
in total knee arthroplasty when significant preoperative deformity
exists. The problems encountered in the patient with severe flexion
contracture derive from the same basic principles but present considerably
different problems with regard to surgical technique, postoperative
stability, and postoperative management.
addressing the surgical techniques and the pre- and postoperative
regimens, the basic principles which lead to problems for the
flexion contracture cases will be outlined. From the introduction
to this chapter and the previous sections it should be clear that
fixed deformity implies relative tightness of soft tissue structures
at the concave side of the deformity, which, in the case of flexion
contracture, is the posterior aspect of the knee. Certainly, the
knee can always be brought into full extension by resecting a
sufficient amount of bone from the distal femur and proximal tibia
(Fig. 11.4.1). It would appear, initially, that this approach
to the problem with treating fixed flexion contracture by generous
bone resection as postoperative rehabilitation, and attention
to the potential quadriceps lag would be all that were necessary.
knee is, in this case, the convex side of the deformity; and the
convex side of the deformity possesses a relative surplus of the
soft tissue sleeve. One might predict in this line of reasoning,
that with the quadriceps being a dynamic mechanism, there would
not be any great problem with treating fixed flexion contracture
by generous bone resection as postoperative rehabilitation, and
attention to the potential quadriceps lag would be all that were
a cursory analysis of the flexion contracture situation is far
from correct. As one corrects the deformity by bone resection
alone, and as the knee is brought into extension, it is true that
the surrounding soft tissue sleeve bulges anteriorly. In fact,
most of the bulge is anterior, but there is also a bulge
or surplus of soft tissue medially and laterally. This is demonstrated
by Figures 11.4.1 and 11.4.2. Diagrammatically it is seen that
with removal of bone to permit full extension, the anterior soft
tissues bulge, or a relative quadriceps laxity develops. However,
as the points on the medial and lateral sides of the knee come
together with such bone resection, Figure 11.4.2 demonstrates
how significant collateral laxity develops.
Sufficient distal femur and proximal tibia bone have been
removed to allow full extension while providing space for
the prosthesis. In the lateral view, the posterior soft tissues
are shown without any laxity. Major laxity or redundance of
tissue is seen to exist anteriorly at the extensor mechanism.
Secondary laxity also develops in the collateral ligaments
as shown in the anteroposterior projection.
reason for the development of collateral laxity is shown in
this line drawing. With removal of bone comprizing the trapezoidal
region in the flexed, lateral figure, points a and
b anteriorly approach one another. The tissue spanning
this area obviously becomes redundant as seen in the extended
lateral view. However, as point a approaches point
b, so also point c approaches point d, and when
viewed in the anteroposterior projection a definite but less
severe redundancy of tissue is seen to develop in the region
of the collaterals.
important problem with the development of such collateral laxity
is the fact that its presence may go totally unnoticed. As the
surgeon brings the knee into maximal extension and assesses the
overall situation, the posterior soft tissues become tight, blocking
further extension or recurvatum. Not only do these posterior tissues
block further extension or hyperextension, but they also provide
medial and lateral stability if the knee is held in a position
of maximum extension with these posterior tissues taut. However,
as soon as even slight flexion is performed and the posterior
tether is released, gross collateral laxity will be evident. In
this general situation, there is not as much laxity in the medial
and lateral tissue as there is anteriorly; however, the resulting
laxity may still be functionally quite significant.
summarize, bone resection alone to correct fixed flexion contracture
can lead to collateral instability on both the medial and lateral
sides of the knee and, furthermore, this laxity will generally
not be evident if collateral stability is tested in maximal extension.
The problem of collateral laxity after bone resection for the
flexion contracture case has implications for some cases of pure
valgus or pure varus fixed deformity. While a primary soft tissue
imbalance after bone resection is, obvious on the convex and concave
aspects of the knee, the flexion contracture situation illustrates
how a secondary, less obvious soft tissue imbalance occurs on
the sites "adjacent" to the main deformity. For the flexion contracture
case, the secondary imbalance is seen to be medial-lateral. If
bone resection alone is used to correct alignment in pure valgus
or varus cases, the same type of secondary imbalance produces
soft tissue laxity in the anterior and posterior aspects of the
knee. The primary imbalance is certainly medial or lateral, but
this secondary imbalance does occur, i.e., quadriceps lag and
recurvation. This is not merely a theoretical consideration but
rather is a clinical fact worth appreciating.
bone to allow correction of the flexion deformity means that a
larger amount of bone is resected than is replaced by the femoral
and/or tibial components. As a result, the relationship of the
attachment points of the ligaments to the resulting prosthetic
joint line is altered. Aside from the general collateral
laxity that can be expected to result, this relocation of the
joint line with respect to the ligament attachment positions invites
more specific problems.
is seen in Figure 11.4.3 that bone resection from the distal femur
alters and shortens the ligament separations in extension while
changing them relatively little in flexion. It could be suggested
that, in the case of flexion deformity, additional bone should
be removed from the distal femur only. Although the collateral
ligaments themselves would be lax in extension, the posterior
soft tissues may provide medial-lateral
at full extension and, with flexion, the collaterals would tighten
and function normally. There is truth to this, but the problem
can present that distal femoral bone resection is limited by the
femoral attachments of the collaterals as well as the posterior
cruciate ligament if there is hope of sparing this. If the surgeon
were relying upon bone resection alone to correct the flexion
contracture, he may then be forced to turn to the tibial side
because of the proximity of the collateral ligament origins.
"catch 22" is that when bone is resected from the tibia in order
simply to achieve full extension, an inappropriate gap is created
between the tibia and the posterior femur when the knee is brought
situation is shown in Figure 11.4.4. Note that bone has been excised
simply to allow full extension. Implantation of the prosthesis
cannot take place until further femur and proximal tibia are removed
equal to the dimensions of the prosthesis. Otherwise, the flexion
contracture would persist. As a result, the relative gap shown
in the diagram will still exist with the knee in flexion even
after prosthetic implantation.
11.4.3. Initial or extra resection of distal
femur allows collateral ligament attachment points to approach
one another when the knee is in extension. However, with
maintenance of the posterior femoral condyles, these attachment
points remain normally separated when the knee is flexed.
In this manner, preliminary or relatively greater distal
femoral excision promotes collateral laxity in extension
and not in flexion.
effect of preliminary or excessive tibial resection is shown
in this series of drawings. Bone has been removed in the upper
right figure to allow full extension without recurvatum, i.e.,
with the posterior tissue tight and no space between the distal
femur and proximal tibia with the knee held in full extension.
When the knee is flexed, however, the gap due to the excised
tibial bone appears and a relative laxity in flexion is evident.
lengthy analysis and discussion has been presented not to show that
fixed flexion contracture is an impossible situation to handle,
but rather to describe its complexity and offer insight into what
is or can be happening when one relies partially or totally on bone
resection to correct the flexion deformity. Cases with as much as
65 degrees of fixed flexion contracture have been handled quite
successfully with standard condylar types of prostheses. They are
possible, but not simple.
this background it is possible to appreciate how important it
is to attempt to correct fixed flexion contracture by means other
than, or in addition to, simple bone resection at the time of
practical, strong consideration should be given to correction
of the fixed flexion contracture prior to total knee arthroplasty.
The first nonsurgical approach beyond physical therapy is serial
casting, even under anesthesia, if necessary. Serial casting for
flexion contracture does several undesirable things, however.
It creates pressure anteriorly on the skin over the knee and posteriorly
at the Achilles tendon. The potential problems of pressure sores
ought to be outlined to all patients undergoing serial casting.
casting also creates a painful compression at the joint surfaces
and promotes further degeneration of articular cartilage. While
effects on intact articular cartilage are of concern for people
with less degenerated joints, other than the attendant discomfort,
such is not a concern for the patient who is to undergo total
knee replacement. At this stage lateral x-rays are suggested to
evaluate objectively the progress of correction during serial
serial casting is impractical or when it is terminated and deformity
persists, consideration can be given to posterior soft tissue
lengthening. Longitudinal posteromedial and posterolateral incisions
may be preferred. They permit Z-plasty lengthening of the hamstring
tendons, exposure of the peroneal nerve, and division of the posterior
capsule without direct exposure of the popliteal vasculature and
with minimal interruption of lymphatic drainage. Intra-articular
pathology, it must be remembered, may be a major obstacle to straightening,
and so one must palpate structures before releasing or lengthening
them to be certain that such action will be helpful. The lateral
knee x-ray of a 71-year-old rheumatoid patient demonstrates how
a posterior soft tissue release would be doomed to failure (Fig.
11.4.5). The joint contours and severe degeneration in this case
were such that further extension could not be achieved by posterior
soft tissue release.
release, if at all successful, can be followed by serial casting.
x-rays of an elderly patient's rheumatoid knee demonstrate
impressive molding of femoral and tibial joint surfaces. In
this case, the irregular joint contours prevented extension
despite posterior soft tissue release.
moderately severe flexion contracture exists, greater than 30°,
after full exposure of the joint, this author will generally perform
a preliminary resection of the distal aspect of the femoral condyles,
removing 3-5 mm of bone. This maneuver avoids having to remake
the anterior and posterior cuts as well as the distal cut later
in the procedure. After this preliminary resection, the distal,
anterior, and posterior femoral cuts are made. Next, any anterior
tibial osteophytes blocking full extension are removed. In fact,
if these are obvious, and especially in milder cases, they should
probably be removed first.
the use of a lamina spreader, while the knee is flexed 90°, division
of the posterior capsule is carefully performed. A perforation
is made through the capsule behind the medial or lateral compartment,
and a right angle clamp is used bluntly to dissect adjacent tissue
away from the capsule prior to sharp division. If insufficient
room for this dissection exists, some proximal tibia is removed
lamina spreader is used to help gain access to the posterior
capsule while capsular incision is being performed.
the knee may be hyperflexed and with a periosteal elevator the attachments
of the gastrocnemius heads elevated from just above the posterior
femoral condyles. If full extension is still not achieved, a few
more millimeters of proximal tibia are removed.
this point, if correction is still imperfect, the options remaining
are: 1) even more generous distal femoral or tibial resection,
2) hamstring lengthening, or 3) reliance on postoperative casting.
Sometimes the posterior skin will feel tight and theoretically
Z-plasty release could be performed. Surgical exposure as well
as skin circulatory conditions would be unfavorable. This author
has no experience with such "skin lengthening" and would not feel
comfortable recommending it. The usual course at this stage is
greater tibial resection and use of postoperative casting.
full extension simply cannot be achieved, then the Universal Total
Knee Instrumentation System described in Chapter 4 cannot be used
in standard fashion, and instrumental improvisation must begin.
An additional 6-7 mm of tibial bone is marked for resection. The
line of the transverse tibial cut is marked with the aid of the
alignment guide, and jig V can be secured to the tibia with 1/8
" drill pins to help with the accuracy of the cut. Care
must be taken to orient the cut perpendicular to the axis of the
tibia on viewing from the lateral aspect.
to the discussion above, and this authors experience, after
performing the transverse tibial cut and achieving a trial reduction
of the components, moderate to moderately severe medial and lateral
instability may be evident. It is important to realize that this
instability will generally not be evident when the knee is brought
out to maximum extension, but will be relatively impressive as
soon as the knee is even mildly flexed. An understanding of the
phenomenon is important.
the performance of a valgus stress test, the surgeon is attempting
to detect medial opening and to effect rotation of the tibia with
respect to the femur within the coronal or transverse plane and
about a point somewhere within the lateral femoral portion of
the knee. Any posterior soft tissue structures bridging the joint
which are tight as a result of maximal extension, and which in
this example lie medial to the axis of attempted rotation, will
tend to prevent medial opening. However, as soon as these posterior
structures are slightly relaxed, in the absence of a competent
primary medial stabilizer, the medial side of the knee opens to
valgus stress. This is the same phenomenon as that which occurs
when one notes relatively good medial stability in forced full
extension, despite medial collateral ligament injury when the
posterior capsule and posterior cruciate ligament are not torn
or significantly stretched.
the presence of collateral instability as described above, the
author has not had or seen a case where proximal or distal collateral
ligament advancement was undertaken for pure flexion contracture
deformity. However, this would be considered if the resulting
collateral instability were obviously unacceptable. Generally,
it is sufficient to plan for a simple knee cage or Lenox Hill
brace in the more unstable cases and to allow the patient to convalesce.
One patient in the authors series for whom long-term use
of a Lenox Hill brace was prescribed had 45° of fixed flexion
contracture and 45° of valgus preoperatively. She discarded her
brace at 89 months postoperatively as she found it unnecessary.
postoperatively, patients are placed in either a Jones dressing
with a posterior plaster splint or a cylinder cast which is bivalved
in the recovery room. Their flexion contractures have a great
tendency to recur in the early postoperative period. A patient
treated with a bivalved cylinder cast can have the cast replastered
at 34 days postoperatively and then wedged into further
extension if this is necessary to address residual flexion deformity.
Those with casts have them removed by 78 days postoperatively
unless there is some strong reason to retain this support. If
such is the case, a manipulation under anesthesia is routinely
performed sometime between the 7th and 14th day postoperatively.
Most of the patients are managed without casts, that is, relying
on splints, if necessary. However, for the more severe cases and
when correction has been clearly incomplete, casting may be indicated.
is very difficult to predict which patients, who start with fixed
flexion contractures and persist with some fixed flexion contracture
at 7 14 days postoperatively, will correct with ordinary
physical therapy. With resurfaced joints, some experience enough
pain relief that they are able, gradually, to stretch out their
flexion contracture. Others have too much muscle spasm and a 1020°
flexion contracture can persist. Despite this resistance in some
cases, the flexion contracture patients as a group still achieve
good results in that a mild residual flexion contracture does
not generally present a major problem (Fig. 11.4.7).
views of a 71-year-old patient with rheumatoid arthritis who
had been nonambulatory with bilateral 65-70° knee flexion
fixed flexion contracture is among the most difficult of total
knee replacement situations. These cases are not easy to treat
successfully and one cannot expect to get every patient with severe
preoperative deformity to full extension permanently. However,
these patients have lived and walked for many years with much
greater flexion contracture than they have postoperatively and
when their joints are resurfaced and their contracture moderately
improved, they still may achieve, as far as they are concerned,
a quite satisfactory final result.
P, Villers, P: Personal communication.
MB: Upper tibial osteotomy for gonarthrosis: the evaluation
of the operation in the last 18 years and long-term results.
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