Algorithm to correct Varus Knee in a TKR

The VARUS KNEEDr Vaibhav Bagaria

Sir HN Reliance Foundation HospMumbai India

Surgical AnatomyPes Anserinus

Superficial MCL

Deep MCL

Joint Capsule

Semi Membranous

Posterior Oblique ligament

MCL

Goal - Symmetrical Gaps

What is a Varus Knee

Maquet’s Line- Load Bearing Axis, Passes from centre of femoral head to Centre of Talus.

Ideally through the centre of Knee

Medial to Centre in case of Varus deformity

Maquet's Line

Maquet’s Line- Load Bearing Axis, Passes from centre of femoral head to Centre of Talus

Classification

Case1

Case 2

Case 3

Case 4

Case 5

Medial Exposure Using Scalpel -Subperisoteal elevation of the medial sleeve

Includes Joint Capsule and deep MCL

Continue with perisoteal elevator to elevate till Meta-physeal flare of tibia.

RanSall Manouveur: flexion- ER @ tibia

Medial Sleeve Creation

Step 1: Osteophytes

Remove all osteophytes from Femur & Tibia as they can tent the medial soft tissue sleeve and consequently shorten the MCL.

Remember to check the Posterior femoral condyle and Posteromedial tibia -> as they tighten extension gap.

Osteophyte Removal

Step 2: PCLMake sure PCL is resected before balancing

PCL is 2ry medial stabiliser so care should be taken not to release the entire sleeve of the tibia because it may cause medial instability

In CR PCL is left intact

PCL Release

Cuts and Balancing

Step 3: Semi Membranosus

If the tightness remains medially, the semimembranosus and posteromedial capsule can be released off the proximal tibia.

Semi Membranosus release

Step 4 - Posterior Oblique Lig

If the gap is tight only medially in the extension during varus valgus stress -> posterior Oblique Ligament can be subperiosteally released.

Is best done in a figure of 4 position

Step 5: Superficial MCL

Assess the flexion extension gap using Lamina Spreader/ Trial Component/ Spacer block - Varus Valgus.

If tight in both - release sub-periosteally SMCL off proximal tibia but not completely of distal tibia

Superficial MCL Release

Pie Crusting

AF PE ( Atrial fibrillation - Pulmonary Embolism)

Structures Responsible

step 6 Pes Release

Step 7: Shift and ResectInitial conservative tibial resection

Based on lateral side: 10mm

Angle perpendicular to long axis with 3 - 5 slope

Measure for size of tray

Downsize and lateralise

Shift & Resect

Shift & Resect

Shift & Resect

Lateralizing the component

Residual LCL laxity

IT band can usually dynamically restore the stability in most cases.

1st options: increase medial release/ medial cut and use thicker Poly

2nd: LCL advancement

AlgorithmCreate a Medial Subperiosteal Sleeve with DMCL

Remove the osteophytes

Take the cuts -remember ER may need to be increased

Check the Gaps

Release Semimembranosus, POL

SMCL ant or Post

Shift and Resect