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TKR in the Valgus Knee

Peter Brooks MD, FRCS(C) Cleveland Clinic

Disclosures

n  Consultant n  Smith and Nephew n  Stryker

Valgus Deformity

n  Less common than varus n  Bone deformity

n  lateral femoral hypoplasia n  Soft tissue problems

n  tight lateral side n  stretched medial side

Bone Deformity

n  Primarily femoral n  unlike varus: tibial deformity n  distal deficiency n  posterior deficiency

n  Complicates femoral component position

Distal Deficiency

n  Sloping joint line n  Must be corrected n  Final joint line parallel to floor

Sloping Joint Line

5mm -> 0mm ->

5mm Distal Lateral Augment Posterior Lateral Deficiency

n  Cannot rely on posterior referencing

n  Results in femoral internal rotation

n  Patellar mal-tracking

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Use the Epicondylar Axis

n  Avoids femoral internal rotation n  Patellar maltracking

n  Check with Whiteside’s Line n  Helps correct soft tissue balance

in flexion

Whiteside’s Line

n  Deepest part of trochlea is normally centered on axis of rotation

n  A line from deepest part of trochlea to highest point of intercondylar notch is at right angles to epicondylar axis

Normal Knee

Whiteside’s Line

3°

Valgus Knee

Whiteside’s Line

10°

Incorrect Rotation

Tibia in Valgus Knee

n  Not the primary deformity n  May have secondary changes n  Lateral plateau deficiency

Soft Tissue Balancing

n  More difficult than varus knees n  Sequential releases n  Tight lateral, +/- stretched medial n  Tight in flexion or extension, or both n  Flexion contracture or hyperextension

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Correction of the Valgus Knee

n  Remove osteophytes n  Assemble trial components n  Assess medial/lateral soft tissues n  In flexion, in extension

Soft Tissue Releases

n  Tight laterally in extension: Release the ITB

n  Tight in flexion and extension: Release the LCL +/- popliteus

n  Still tight in extension: Release the ITB

n  This works for almost all knees

Osteophytes LFC

Tight in Extension – most common

ITB at the Joint Line

Tight in Flexion and Extension

LCL +/- Popliteus from lateral epicondyle

Combined Flexion Contracture

n  PCL substitution n  Extra distal femur resection n  Release posterolateral capsule by

multiple perforations n  Lateral head of gastrocnemius

Insall “Pie-Crust” Technique And …

n  Beware of the peroneal nerve, and warn the patient beforehand, especially with a combined flexion contracture

n  Patellar tracking is often a problem n  Lateral release may be needed

Inside-out Lateral Release

Preserve superior lateral geniculate artery

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Implant Selection

n  Mild valgus n  CR or PS

n  Moderate valgus n  PS, may need augments

n  Severe valgus with medial instability n  Constrained (TS or hinge) n  Stems, augments

Clinical Example

n  JK, 72 yr old female n  OA right knee n  Severe valgus deformity n  Marked instability

Instability: valgus, hyperextension Implant Selection

n  Severe Valgus n  Medial stretching n  Hyperextension

n  Stabilizes medial side n  Prevents over-stretching peroneal nerve

Total Stabilized TKR