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Lateral femoral sliding osteotomy
LATERAL RELEASE IN TOTAL KNEE ARTHROPLASTY FOR A FIXED
VALGUS DEFORMITY
J. Brilhault, S. Lautman, L. Favard, P. Burdin
From Trousseau University Hospital of Tours, France
e treated 13 patients who had a fixed valgus
deformity of the knee with a semiconstrained total
knee arthroplasty combined with advancement of the
lateral collateral ligament by means of a lateral femoral
condylar sliding osteotomy. At follow-up of between one
and 6.5 years all patients were assessed using the Knee
Society score. The mean knee score improved from 32 to
88 and the functional score from 45 to 73. The mean
tibiofemoral angle was corrected from 191° to 180°.
There was no postoperative tibiofemoral or patellar
instability and, in most knees, distal transposition of the
lateral femoral condyle achieved satisfactory stable
alignment.
W
J Bone Joint Surg [Br] 2002;84-B:1131-7.
Received 17 September 2001; Accepted after revision 26 February 2002.
The importance of restoring mechanical alignment after
total knee arthroplasty (TKA) is widely accepted. This,
however, may be difficult in the presence of a fixed valgus
deformity.1 Good overall alignment with a horizontal tibiofemoral joint line is obtained when the bone cuts are perpendicular to the mechanical axis of the femur and the tibia.
In doing this, however, the tibiofemoral gap created may
have a trapezoidal shape, implying imbalance of soft tissues
when using a standard, semiconstrained prosthesis. Two
options have been proposed to correct such an imbalance.
One is to tighten the medial collateral ligament,2,3 and the
other, used by most surgeons, is to release the lateral supporting structures.1,2,4-9 The second option, especially when
releasing the lateral collateral ligament (LCL), is still con-
J. Brilhault, MD
S. Lautman, MD
L. Favard, MD, Professor of Orthopaedics
P. Burdin, MD, Head and Professor of Orthopaedics
Department of Orthopaedic Surgery and Traumatology, Trousseau University Hospital of Tours, 37044 Tours Cedex, France.
Correspondence should be sent to Dr J. Brilhault.
©2002 British Editorial Society of Bone and Joint Surgery
0301-620X/02/812824 $2.00
VOL. 84-B, No. 8, NOVEMBER 2002
troversial and may cause postoperative mediolateral instability.10 In order to prevent such instability we have
developed a balancing technique using a sliding osteotomy
of the lateral aspect of the lateral femoral condyle. It allows
precise lengthening of the lateral structures while internal
fixation by screws gives immediate stability and allows
normal postoperative care.
We now review the results of this technique in TKA for a
fixed valgus deformity. We attempt to evaluate the amount
of slide needed to achieve a rectangular tibiofemoral gap.
Patients and Methods
Between January 1994 and August 1999, 96 patients with
valgus deformities underwent TKA. Thirteen presented with
fixed valgus deformities (i.e. the valgus deformity was not
passively correctable) and required a specific ligament balancing procedure to achieve correction of the deformity and
proper ligamentous stability (Table I).
There were 12 women and one man with a mean age at
the time of surgery of 73 years (69 to 81). The diagnosis
was osteoarthritis in 12 knees and rheumatoid arthritis in
one. A lateral Keblish approach was used in 11 knees and a
medial parapatellar approach in two. A tibial tubercle osteotomy was carried out in seven knees to facilitate exposure
but not for distal patellofemoral realignment. A posterior
stabilised prosthesis was used in 12 knees and a cruciateretaining design in one (Genesis I and II; Smith-NephewRichards, Memphis, Tennessee).
Data were collected according to a prospectively
designed protocol. All preoperative evaluations and surgical
procedures were carried out by the two senior authors (LF
and PB). All follow-up evaluations, and the assessment of
the results, were by those who were not directly involved
with the patients. The hospital records were reviewed and
the pre- and postoperative radiographs re-evaluated. Clinical
and radiological evaluations were done before and at a minimum of one year after surgery. Special attention was given
to laxity in the frontal plane. The varus and valgus examination was undertaken in a routine clinical manner with the
knee flexed to 20°. Laxity was measured subjectively in
degrees as follows: none (0° to 5°), mild (6° to 9°) and moderate (10° to 14°) and recorded independently for the lateral
and medial sides (Table II). Clinical data were summarised
1131
1132
J. BRILHAULT, S. LAUTMAN, L. FAVARD, P. BURDIN
Table I. Clinical details and Knee Society scores (maximum 100) for the 13 patients who required lateral release in TKA for a
fixed valgus deformity
Preoperative
Case
Age
(yrs)
1
2
3
4
5
6
7
8
9
10
11
12
13
Mean
75
69
76
71
73
81
69
69
78
72
75
78
68
73
Gender
F
F
F
F
F
M
F
F
F
F
F
F
F
Follow-up
Functional
score
Knee score
Months
Functional
score
Knee score
35
40
20
20
30
5
30
35
30
60
35
55
25
32
66
56
72
33
55
50
65
24
65
31
21
5
10
45
18
67
78
58
60
58
58
64
72
41
12
78
64
56
75
80
90
100
75
75
60
59
65
70
50
90
55
73
93
93
94
86
83
89
75
86
89
84
94
79
93
88
using the 100-point scoring system developed by the Knee
Society.11 For radiological evaluation we used long-leg
standing anteroposterior radiographs, with lateral and skyline views.12
Alignment of the knee is reported here as the tibiofemoral mechanical angle (TFMA, Fig. 1).4 The femoral
mechanical axis was defined as the line drawn between the
centre of the femoral head and the centre of the knee. The
tibial mechanical axis was defined as a line drawn between
the centre of the knee and the centre of the ankle. The
TFMA was measured as the angle formed medially at the
knee by the intersection of the femoral and tibial mechanical axes. The tilt of the femoral condylar surface was measured by the condylar-hip angle (CHA), defined as the angle
formed medially between the femoral mechanical axis and
the femoral knee joint line. The angle of the tibial plateau
was measured by the plateau-ankle angle (PAA), defined as
the angle formed medially between the tibial mechanical
axis and the tibial knee joint line.13 Patellar height was
measured on a lateral view with the knee in 30° of flexion.
We used the method of Insall and Salvati14 to describe the
patellar height and that of Caton et al15 to describe the patellar articular height in relation to the tibiofemoral joint line.
Using the skyline view, the tilting angle and the lateral shift
of the patella were measured (Fig. 2).16 The patellar tilt was
defined as the angle between a line from the anterior limits
of the femoral condyles and the equatorial line of the patella
preoperatively, or a line drawn along the prosthesis-bone
interface postoperatively. A medially open angle was
defined as positive. Patellar lateral shift was defined as the
distance between the crest of the patella and a line drawn
through the central area of the femoral condyles. Postoperatively, we used the centre of the patellar prosthesis. A lateral
translation was defined as positive.
For statistical analysis we used the Wilcoxon rank test.
Significance was accepted at a p value of less than 0.05.
Operative technique. We use a lateral parapatellar
approach. The musculature of the anterior tibial compart-
Table II. Medial and lateral laxity recorded preoperatively and at followup for the 13 patients who required lateral release in TKA for a fixed valgus
deformity
Preoperative
Follow-up
Case
Medial laxity Lateral laxity
Medial laxity Lateral laxity
1
2
3
4
5
6
7
8
9
10
11
12
13
None
Mild
None
None
None
None
Mild
None
None
None
None
None
None
Mild
None
None
Mild
None
Mild
None
Mild
None
Mild
None
Mild
None
Mild
None
Moderate
Moderate
Mild
Moderate
Moderate
None
Mild
Moderate
Mild
Mild
Moderate
None
None
None
None
None
Mild
None
None
Mild
None
None
None
Mild
ment and the iliotibial band from Gerdy’s tubercle are elevated subperiosteally. The meniscal-capsular-fat-pad flap is
everted on the lateral inferior geniculate artery according to
Keblish.5 In severe valgus deformities, a stepcut osteotomy
of the tibial tubercle is required to facilitate exposure and
patellar eversion. Both cruciate ligaments are usually sacrificed.
A retropatellar osteotomy, parallel to the anterior surface
of the patella, is completed first. The thickness of the patellar button is chosen to approximate to the patient’s own
patellar thickness. Intramedullary instrumentation is used to
fashion the distal femoral bone cut perpendicular to the
femoral mechanical axis and based upon the preoperative
radiographs. The medial femoral condyle is used as a reference to determine the level of distal femoral resection in
order to remove an amount of bone medially which corresponds to the thickness of the femoral component. This preserves the level of the prosthetic joint line. Posterior
condylar osteotomies are undertaken in the same way allowing for any erosive changes at the back of the lateral conTHE JOURNAL OF BONE AND JOINT SURGERY
LATERAL FEMORAL SLIDING OSTEOTOMY
1133
Shift
Tilt
Fig. 2a
CHA
TFMA
PAA
Shift
Tilt
Fig. 1
Fig. 2b
Diagram showing alignment of the
lower limb: tibiofemoral mechanical
angle (TFMA), condylar hip angle
(CHA) and plateau-ankle angle
(PAA).
Diagram showing patellar axial positioning a) before operation and b) at follow-up.
dyle. The posterior condylar line is used as the sole
rotational reference. A proximal tibial cut perpendicular to
the tibial mechanical axis is undertaken using extramedullary instrumentation. The resection is based on the medial
tibial plateau.
Once the bone cuts are achieved, the tibiofemoral gap is
trapezoidal in shape. A lateral release is then required to
correct the deformity and allow a rectangular tibiofemoral
gap (Fig. 3). This requires a lateral femoral sliding osteotomy which is performed as follows (Fig. 4).
Step 1. Using a thin reciprocating saw, a frontal cut is made
at the distal angle of the anterior chamber parallel to the
anterior femoral cortex.
Step 2. An axial cut is then made perpendicular to the first
cut, at the proximal part of the posterior condyle resection.
Step 3. A sagittal cut is then made perpendicular to both
first cuts. It separates a bone block which includes the
insertions of the LCL and popliteus, and should be at least
5 mm thick.
Step 4. The bone block is retracted to give access to the posterior compartment of the knee. A capsulotomy is undertaken along the proximal border of popliteus from the bone
block to the midline. This is important to prevent a flexion
contracture.
VOL. 84-B, No. 8, NOVEMBER 2002
Fig. 3
Diagram showing correction of the deformity and achievement of a rectangular tibiofemoral extension gap.
1134
J. BRILHAULT, S. LAUTMAN, L. FAVARD, P. BURDIN
Step 1
Step 2
Fig. 4a
Fig. 4b
Step 3
Step 4
Fig. 4d
Fig. 4c
The best position for fixation of the bone block is determined using spacer blocks. Rectangular tibiofemoral gaps
must be obtained both in flexion and extension. The distal
slide of the bone block is adjusted with the knee extended
with the appropriate spacer (Fig. 3). The posterior slide may
Diagrams of the lateral femoral bone block osteotomy showing a) the anterior
cut (step 1), b) the proximal cut (step 2), c) the final cut (step 3), and d) the
posterolateral capsulotomy (step 4).
be adjusted in the same way if necessary. The bone block is
temporarily held by Kirschner wires to check the ligamentous tension and the stability of the knee. Two or three 3.5
mm screws are used for final fixation. The screw length usually corresponds to the thickness of the lateral condyle. Care
THE JOURNAL OF BONE AND JOINT SURGERY
LATERAL FEMORAL SLIDING OSTEOTOMY
1135
Table III. The tibiofemoral alignment pre- and postoperatively and at follow-up for 13 patients who required lateral
release in TKA for a fixed vagus deformity
Tibiofemoral mechanical
angle (degrees)
Condylar-hip angle
(degrees)
Plateau-ankle angle
(degrees)
Case
Preoperatively
Follow-up
Preoperatively
Follow-up
Preoperatively
Follow-up
1
2
3
4
5
6
7
8
9
10
11
12
13
Mean
194
190
193
203
185
194
183
188
189
194
190
195
186
191
181
182
185
182
182
180
173
180
180
180
181
176
180
180
92
97
95
95
94
92
96
94
94
95
99
95
97
95
90
89
91
92
88
90
87
88
89
89
90
89
93
90
81
84
85
88
83
87
97
89
84
85
85
91
88
87
90
93
95
89
94
90
86
92
91
85
91
86
87
89
Table IV. Radiological patellar patterns preoperatively and at follow-up for the 13 patients who required lateral release in TKA or a fixed valgus deformity
Tilt
(degrees)
Caton15
method
Lateral shift
(mm)
Insall-Salvati14
method
Case
Preoperatively
Follow-up
Preoperatively
Follow-up
Preoperatively
Follow-up
Preoperatively
Follow-up
1
2
3
4
5
6
7
8
9
10
11
12
13
Mean
8
1
4
5
0
1
3
3
6
2
1
5
7
3.5
2
0
4
4
0
-1
0
1
1
-1
2
1
2
1.1
-9
2
3.5
-3
-1
1
5
2
-6
-1
-1
0
10
0.2
-2
-1
-1
6
-2
-2
2
-1
2
5
13
2
-5
1.2
0.86
0.78
1.16
0.81
1.13
0.82
0.80
0.79
0.75
1.11
0.90
1.25
1.16
0.9
0.71
0.91
1.14
0.85
1.05
0.88
0.77
0.49
0.63
0.76
0.49
1.16
0.97
0.8
1.22
1.11
1.36
1.32
1.37
1.04
1.03
0.94
0.94
1.23
1.02
1.44
1.28
1.2
1.23
1.41
1.49
1.30
1.29
1.07
1.20
1.06
0.90
1.20
1.25
1.35
1.13
1.2
should be taken not to interfere with the cruciate-substituting box. Any prominent bone is trimmed in order to accommodate the trial femoral component. In our experience this
has never threatened the insertions of either the LCL or popliteus. With the knee now ready for a trial reduction an
appropriate thickness of tibial insert is determined and the
tibial component rotated into its correct alignment with the
femur. Patellar stability is finally checked.
After the components have been cemented, the lateral
soft-tissue gap in flexion is determined after self-adjustment
of the patellar tendon. The lateral composite flap is tailored
to fill that gap in a tension-free manner. Skin closure over a
drain is carried out in a routine tension-free fashion. A bulky
compression dressing with splints is used for approximately
three days. Rehabilitation is not delayed since internal fixation gives immediate stability and allows full weight-bearing and normal postoperative care.
Results
A constrained prosthesis has not been required after ligament balancing because of instability. All patellae were
VOL. 84-B, No. 8, NOVEMBER 2002
resurfaced and all components were cemented. The degree
of transposition of the bone-block which was required in
order to obtain a rectangular tibiofemoral gap, in both flexion and extension, was a distal displacement alone in 12
knees and a combined distal and posterior displacement in
one. Although significant, the transpositions were sufficiently small not to threaten the insertion of the LCL and
popliteus when trimming any prominent bone.
There were five complications. Four patients developed a
deep-vein thrombosis which was confirmed by Doppler
examination, one had a superficial wound problem and one
developed a pseudarthrosis of the sliding osteotomy. Reoperation was necessary for this last patient because of pain,
albeit without instability. Bony fusion was achieved with a
satisfactory outcome. There were no cases of palsy of the
peroneal nerve or of patellar instability.
The mean follow-up was 56 months (12 to 78). All
patients were satisfied with the result of their operation and
reported decreased pain and improved function. At followup, some degree of medial or lateral laxity persisted in eight
knees (12 knees had medial or lateral laxity preoperatively).
The clinical details are shown in Tables I and II.
1136
J. BRILHAULT, S. LAUTMAN, L. FAVARD, P. BURDIN
Fig. 5a
Fig. 5b
Case 12. Radiographs a) before operation and b) at follow-up.
Radiological examination. The mean alignment of the
limb had been corrected from 191° (183 to 203) to 180°
(173 to 185) after operation. No patient had a significant
change in patellar height as measured by the Insall-Salvati
method.14 Using the method of Caton et al,15 the patellar
articular height decreased, but stayed within the normal
range (0.82 to 1.12). The patellar tilt increased and the lateral shift decreased. Radiological data are detailed in Tables
III and IV.
Discussion
The technique of ligamentous balancing by lateral femoral
sliding osteotomy was successful in restoring stable alignment in most patients with a fixed valgus deformity when
using semiconstrained TKAs (Fig. 5).
The most challenging aspect of a TKA in the presence of
a valgus deformity is to conserve ligamentous stability after
limb alignment. It is our view that this is possible by doing
the bone cuts first and then respecting the LCL during ligament balancing. Primary bone cuts allow positioning of the
components perpendicular to the mechanical axis of the
limb. Once the bone cuts have been done achievement of a
rectangular flexion-extension tibiofemoral gap implies a lateral opening of the tibiofemoral gap. Two structures are then
involved, the posterior cruciate ligament (PCL) and the lateral stabiliser of the knee. The PCL provides a central pivot
point which limits the lateral opening and suggests that it
should be divided. Among the lateral structures, the iliotibial band is a secondary lateral stabiliser of the knee in extension.11 Subperiosteal elevation from Gerdy’s tubercle, in
continuity with the anterior tibial fascia, which is offered by
the lateral approach, allows sufficient exposure and lateral
release. The lengthening of the iliotibial band by Z-plasty,
VY-plasty, transverse section or multiple puncture tech-
niques may allow excessive correction and lead to secondary instability in extension. As cadaver and surgical studies
suggest, the LCL is the primary lateral stabiliser of the knee.
When released, it allows greater distraction of the lateral
space in flexion than in extension.11 In our experience,
release of the LCL allows a wide opening of the lateral
aspect of the joint. This may be excessive and produce lateral instability in flexion. Alignment in the presence of a
fixed valgus deformity implies the need for lengthening of
the LCL just as lateral stability implies its retention.
Krackow2 proposed re-approximating the distal tendinous
stump of the popliteus tendon to the distal remnant of the
LCL in order to manage this problem, but secondary
stretching of the repair may produce lateral instability. A lateral femoral sliding osteotomy allows precise lengthening
of the LCL in the desired plane without producing excessive
lateral opening in flexion. Internal fixation gives immediate
stability and permits normal postoperative management, and
bony fusion prevents secondary lengthening. Pseudarthrosis
of the osteotomy is, however, the principal pitfall of the
technique. Care must therefore be taken to achieve primary
stability with good internal fixation. This is not always easy
in the presence of significant osteoporosis. In such knees we
suggest the use of a one-third tubular plate applied as a tension-band plate.
The authors gratefully thank Mr T. J. Wilton, MA, FRCS, of the Derbyshire
Royal Infirmary for his editorial assistance in the preparation of this manuscript.
No benefits in any form have been received or will be received from a
commercial party related directly or indirectly to the subject of this article.
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