Arthoplasty workshop dhulikhel 2018

Suresh Pandey
Consultant Orthopedic Surgeon
Chitwan Hospital,
Manakamana Hospital, Bharatpur
Arthroplasty symposium Dhulikhel 2018

Principle
Total knee replacement is really all about
Alignment
Balance

Amount of bone resection
Rule of thumb
replace (by
prosthesis) as
much as you cut
(bone) and
remove.
8 – 10 mm from distal femur
and proximal tibia

Restore Mechanical axis
At the end of surgery
the line joining the
centre of the head of
the femur and the
centre of the ankle
should go through
the centre of the knee

Definition
Varus deformity is defined as
malalignment in Varus of the lower limb
with the axis at the knee as against the
natural femorotibial valgus orientation

Biomechanics
 60% of the weight passes through the medial condyle
 Extreme knee bending occurs while squatting, sitting
cross legged which is a part of lifestyle and may be
responsible for early arthritis

What happens in varus knee?
 Once varus occurs the
weight transmission
occurs more medially
(Red line)
 This causes the
deformity to progress
further
VISCIOUS CYCLE

Bone and soft tissue in Varus Knee
 BONE –
Deformity
and/or loss
 SOFT TISSUE –
contracture or
laxity

Preop planning
1.LIGAMENT BALANCING –
TIGHT MCL; STRETCHED
OUT LCL
2.MEDIAL BONE
DEFECTS
RECONSTRUCTION.

A/P STANCE ABDUCTION STRESS
35°
11°
CORRECTABLE VARUS DEFORMITY

VALGUS STRESS VIEW
FIXED DEFORMITY
30°
SINGLE JOINT WT. BEARING

Approach
 surgeon preference
 prior incisions
 degree of deformity

Incision planning
 Multiple incision, choose more lateral
 blood supply comes from medial side
 Generally safe to cross previous transverse incisions at
right angles
 Ensure adequate skin bridge

 Medial parapatellar
 Midvastus
 Subvastus

Medial Parapatellar
 Familiar for most orthopaedic
surgeons
 Excellent exposure even in
challenging cases

Varus deformity
Structures involved and
contributing to Varus
deformity are….
 MCL
 Posteromedial capsule.
 Postero medial osteophytes
 Exessive bone on medial
side
 Pes anserinus
 Semimembranosus
 USUALLY ASSOC WITH MEDIAL
BONE LOSS

Medial Release
 The medial release is done in a
graduated fashion checking at
every stage if balance has been
achieved.
 The medial release starts with
the elevation of the medial
capsulo – periosteal flap from
the proximal tibia
 Then the deep MCL is released
from the medial and
posteromedial border

Release…
 The tight posteromedial capsule
is released
 Then the superficial MCL is
released by subperiosteally
elevating a flap down the
medial and posteromedial
border of the tibia if not
corrected
 Alternatively it can be done by
pie crusting

 Further release is done by
detaching the insertion of the
semimembranosus tendon
 If still release is required then
the pes anserinus insertion can
be elevated (be careful not to
enter the bursa)
Rarely needed

Small defect
< 6 mm
Medium defect
6 to 12 mm
Large defect
> 12 mm
MEDIAL BONE DEFECTS - SIZE

Contained Peripheral Composite
MEDIAL BONE DEFECTS -
LOCATION

3. BONE GRAFT
ALLOGRAFT
AUTOGRAFT
4. WEDGES ANGULAR
RECTANGULAR
5. CUSTOM MADE COMPONENT
1.SMALL DEFECT RESECT MORE BONE
2. CEMENT ( With or without screws)
TREATMENT OPTIONS

LOWER THE TIBIAL RESECTION LINE
SMALL DEFECT < 6 mm

Medium defect 6 – 12mm
Increased tibial bone
resection
Remove posteromedial
oseophytes
Down size tibial
component
Shift component
laterally
The Tibial Base Plate
should cover 90% of the
Bone Defect

BONE DEFECTS 6 – 12mm
SCREW WITH CEMENT MANTLE
Cement
+
Screws

Large defect
A Defect
Larger than 25% of
Medial Tibial Plateau
&
More than 10 mm in
Depth

Large defect

Valgus knee
Challenge to surgeon
Preop planning
Be ready with all the
inventory

Definition
Valgus deformity is defined as
malalignment
exceeding the natural
femorotibial valgus orientation,
typically
greater than 70 to 100

ANATOMY OF LATERAL STRUCTURES -
ITB
ILIOTIBIAL BAND

ANATOMY OF LATERAL STRUCTURES - LCL
LCL
POSTEROLATERAL CAPSULE
ARCUATE LIGAMENT

ETIOLOGY
 RA
 Hypoplasia lat condyle
 Post Trauma
 Metabolic

Bone and soft tissue change
BONE LOSS
 Dysplastic lateral
Femoral Condyle
 Lateral Tibial Condyle
SOFT TISSUE
 Tight Lateral Structures
 Elongated Medial
Structures

CLASSIFICATION
Krackow et al
 Type 1 – lateral femoral
bone loss, lateral soft
tissue contracture and
intact medial soft tissues

Krackow et al
 Type 2 – type 1 +
lengthened medial soft
tissues
CLASSIFICATION

Krackow et al
 Type 3 – a severe valgus
deformity with
malpositioning of the
proximal tibial joint line
(e.g., secondary to high
tibial osteotomy)
CLASSIFICATION

Approach
 Medial parapatellar Vs Lateral

Medial parapatellar
 Friendly
 Useful for flexible deformity
 Easy patellar eversion
 Adequate exposure

Lateral
 Useful for addressing lateral
contractures but difficult
patellar eversion

Lateral approach…
 Advantages
 useful for a fixed valgus deformity
 preserves blood supply to patella
 prevents lateral patellar subluxation
 allows direct access to lateral side in a valgus knee

Lateral approach
 Disadvantages
 technically demanding
 medial eversion of patella is more difficult
 may require tibial tubercle osteotomy

Problems and solutions
TIGHT LATERAL STRUCTURES
- requiring release to balance
extension gaps

Problem
HYPOPLASTIC
LATERAL CONDYLE
- Error while using 30
external rotation
plate to judge femoral
component rotation

Problem
POOR PATELLAR
TRACKING

Problem
BONE DEFECTS
– may require grafting

Problem
PERONEAL NERVE PALSY
 3% – 4% Incidence
 severe valgus + flexion deformity
 Aetiology – acute stretching of the nerve
 Immobilise the knee in some degree of flexion and
then gradually extend to avoid sudden stretching of
the nerve

PRINCIPLES OF THE CORRECTION OF A
VALGUS DEFORMITY
 Restoration of frontal alignment
Proximal tibia cut at 90°
Distal Femur Cut at 3° to the anatomical axis
 Soft-tissue balancing in extension - avoid extra release
of medial soft tissues
 Flexion gap stability using bone cuts (“Parallel to
Tibial Cut Technique”)
 Avoid soft tissue balancing in flexion

TKR Designs
 PCL Retaining (CR)
 PCL Substituting (PS)
 Fixed Bearing (FB)
 Rotating Platform (RP)
 Constrained (TCIII)

ADVANTAGES OF PS DESIGN
Applicable to all deformities
 Improves Patellofemoral tracking
 Lateralization of femoral component
 Lateralization of tibial component
 Better Kinematics
 PCL release is necessary to correct deformity

TRADITIONAL LATERAL
RELEASE
 FEMORAL SIDE –
1. Lateral capsule,
2. LCL,
3. Arcuate ligament,
4. Popliteus tendon,
5. Lateral femoral
periosteum and
6. Lateral intermuscular
septum.
 TIBIAL SIDE –
ITB from Gerdy’s tubercle

CORRECTION OF A VALGUS DEFORMITY
THE ORIGINAL DESCRIPTION
Insall, Scott, Ranawat JBJS 1979
 The Iliotibial Band is cut transversely above the
joint line
 A routine longitudunal lateral release
 LCL, Popliteus Tendon and Posterior Capsular
attachments are released from the femoral side

LCL
POPLITEUS TENDON

THE PROBLEM
 Prior techniques had an unacceptably high
rate of early- and late-onset instability.
 The need for highly-constrained TKR devices
became increasingly common.
 The goal was to develop a soft-tissue
technique which would minimize these risks.

THE “INSIDE-OUT TECHNIQUE” FOR THE
CORRECTION OF A VALGUS DEFORMITY
JBJS DECEMBER 2004, SEPT 2005
Order of Release:
1. Complete Release of the PCL
2. Release of the Posterolateral Capsule up to the
Posterior Border of the ITB at the level of Tibial
Bone Cut in extension.
3. Pie-crusting of the IT Band
4. The LCL and Popliteus are preserved to limit
posterolateral instability.

VALGUS KNEE: RELEASE
Controlled Lengthening
of IT Band
“Pie-Crusting”

PCL
POSTEROLATERAL CAPSULE
ITB

Bone cut
Cut less bone in the
Valgus deformity
 Cut 8mm of the Proximal Tibia
 Cut 9mm of the Distal Femur
(as opposed to the typical 10mm and 10mm)

WHAT IS A BALANCED KNEE
IN FLEXION?
Requires a snug rectangular
space at 90° of flexion

ROTATIONAL ALIGNMENT OF THE FEMORAL
COMPONENT
 Epicondylar Axis
 Whitesides Line

DISADVANTAGES IN A VALGUS KNEE
 Epicondylar Axis
 Difficult to accurately determine epicondyles
 Whitesides Line
 Difficult to accurately determine depth of the
trochlear notch
 Fixed Amount of ER
 May be mislead by femoral hypoplasia or posterior
condylar wear, especially in a valgus deformity

Co-planar

THE PARALLEL CUT TECHNIQUE
18 mm

SUMMARY
1. The “Inside-Out Technique” for the correction of
a valgus deformity is easy & reproducible.
2. Very few PF Complications
3. No late failures up to 15 years
4. The need for constrained (TCIII) implants is
significantly reduced.

Thank You for kind attention

Arthoplasty workshop dhulikhel 2018

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Arthoplasty workshop dhulikhel 2018