TKA in Fixed-valgus deformity knee is difficult and
challenging to surgeon.
The correction varus deformity is easier than valgus
Factirs that makes TKA in valgus knee difficult are :
ambiguity regarding sequence of ligament release.
More chances of patellofemoral maltracking.
Common peroneal palsy.
More chances of flexion-extension gap mismatch.
In valgus knee, deficient in lateral bone and cartilage leads
to adaptive changes occur in following structures,
Contractures and tightening of
postero lateral capsule
lateral collateral ligament
lateral intermuscular septum.
Stretching and attenuation of the medial ligaments can
Femur—The postero lateral femoral condyle is smaller.
Tibia—The tibia is externally rotated, the tibial tubercle
is positioned laterally.
The lateral plateau :central bone resorption and peripheral
Patella—The patella is often subluxed laterally. The lateral
facet is deformed (flattened or concave),with large traction
osteophytes , Patella alta.
Ipsilateral hip, ankle and foot to be examined ----
whether they are contributing to knee pathology
Alignment of both lower extremities is observed for
Stability in coronal and sagital plane should be looked
To correct large angular deformities bone grafting and
modular implants may be needed.
Patellofemoral tracking thoroughly examined for any
Posterior structures examined for any popliteal cyst
PRE OPERATIVE EVALUATION
AP View : Weight bearing AP view superior than supine.
Lateral View :
Patellar height and patellofemoral joint can be visualised.
As patella alta common with valgus knee this view is
Normal :1.02+/- 0.2.
Patella alta : (LT/LP 1.2),
Patella baja (LT/LP 0.8).
Merchant View :
Superior than lateral view
Provides the most optimal
Standing 52-Inch Cassette
(“Three Joint View”) :
Gives information about,
The overall alignment (mechanical axis) of the lower
To know the degree of varus or valgus alignment at both
knees and their relative leg length.
Presence of important extra-articular deformities (with prior
trauma ,Paget’s disease)
In young patients --PCL substituting posterior stabilized
In elderly low-demand patients ---constrained condylar
Cases with bone deficiency---a modular implant with
metal augments, offset stems, and variable tibial
polyethelene thicknesses may be useful.
Skin incision -- anterior midline incision.
For arthrotomy -- medial parapatellar retinacular
Patellar maltracking is more common.
Increased potential for inaccurate flexion-extension gap
Increases external rotation of the tibia
Access to the posterolateral corner is more difficult
Vascularity to the quadriceps patella tendon (QPT)
mechanism and lateral skin is at risk.
Some surgeons prefer lateral approach for valgus knee
Improved access to the pathologic postero lateral corner
Preserves vascularity because the medial side is
Centralizes the QPT mechanism, which optimizes patella
Not routinely used because
Damage to genicular arteries
Not familiar with techniques of exposure and
Femoral component rotational alignment is important in
the valgus knee to attain,
Equal flexion extension gap
Normal patellofemoral tracking
Joint line level
The intramedullary alignment rod
should be slightly medial to the
center of the patellar groove.
The cutting guide is set at a 5°
This will align the joint surface
perpendicular to the mechanical
axisof the femur and parallel to
the epicondylar axis.
In some cases resection from
the medial side results in
minimal or no resection from
the lateral side of the distal
For accurate rotational alignment either the AP
axis or the epicondylar axis of the femur is used as
anatomical reference for resection.
The posterior femoral condyles are unreliable as
posterolateral femoral condylar deficiency
The tibial cut should be made at 90+/- 2 degrees to the long
axis of the tibial shaft in both the coronal and sagital planes.
Over-resection of the proximal tibia to address a bony defect,
and to create a flat surface for the tibial component may
damage ligament attachments and may sacrifice excessive
amounts of bone.
The medial tibia is referenced and 10 mm of bone is resected.
Bony defects can be addressed with cement, bone, or metal
The MCL must be protected during resection.
TIBIAL CUT :
SOFT TISSUE RELEASE
The purpose of our release is to provide ligamentous
balance with rectangular flexion and extension gaps ,while
maintaining lateral side stability of the knee in flexion.
The release can be a full release, partial release, or Z-
Release is performed in a step-by-step controlled fashion
and reassessed with laminar spreaders after each step
At the end of release,
The mechanical axis passes through the centre
of the knee.
The flexion and extension gaps are equal and
The order of release varies among surgeons.
LCL and popliteus
lateral stability in both
flexion and extension.
IT Baand and
provides lateral stability
only in extension.
Release in flexion first and then proceed in extension.
Tight in both in
Flex and ext
LCL and popliteus
ITB &Post capsule
PCL, IMS, Lat gastro
Tight only in
Based on palpation of taut soft tissues followed by their
selective release with multiple stabs with 15 no..blade.
Multiple horizontal incisions given from inside to out.
Begin at the level of the joint line and can extend 10 cm
This works like a tensor and allows the lateral tissues to
lengthen and slide with some degree of continuity
It is performed only after final implantation of all total knee
components, just before wound closure.
MEDIAL LIGAMENT ADVANCEMENT
It should be done when medial ligaments are too lax, after
complete release of lateral ligaments
Described by Krackow
Proximal advancement on femur
Distal advancement on tibia
Elevation of the femoral origin of the medial collateral
Proximal advancement using a locking-loop type of
suture within the substance of the ligament.
This suture is secured around a screw and washer with a
staple placed at desired site on medial epi-condyle.
Patellar maltracking is often associated with a valgus
If necessary a lateral retinacular release should
VALGUS KNEE WITH BONE DEFECT
Arthritis with angular deformity
Lateral condylar hypoplasia
Post surgical ( HTO, TKA )
Contained or cavitary defects ---intact rim of cortical
bone surrounding the deficient area.
Noncontained or segmental defects ---more peripheral
and lack a bony cortical rim.
Small defects (<5 mm) typically are filled with cement.
Contained defects can be filled with impacted
cancellous bone graft.
Larger noncontained defects can be treated by
Structural bone grafts(auto or allografts )
Screws with cement or graft.