Valgus TKA: Balancing Technique Michael Zlowodzki MD University of Minnesota Department of Orthopaedic Surgery

HPI 66 y/o male 5 year h/o L knee pain Tried NSAIDS, Steroid injections,

Physical Exam Apparent valgus deformity ROM: Stable to v/v stress; not correctable Cms intact

17° combined left knee valgus 11° in femur 6° in proximal tibia

VALGUS KNEE: Classification Type 1: Minimal valgus with medial soft-tissue stretching Type 2: >10° with medial soft-tissue stretching Type 3: Severe valgus after prior osteotomy with incompetent medial soft tissue envelope

TECHNICAL ASPECTS Medialize intramedullary alignment guide by 5-10 mm (because valgus deformity is at midshaft femur level) Overcorrect by setting the valgus angle of the guide to 3° instead of 6° Align the distal femur cutting guide parallel to the epicondylar axis (instead of posterior condyles)

Deformity correction Stability

Too vigorous soft tissue releases might require more constraint implants

AFFECT FLEXION AND EXTENSION EQUALLY Structures that origin close to the epicondylar axis of femur LCL (slightly more effective in extension) Popliteal tendon (slightly more effective in flexion) Posterolateral corner capsule (slightly more effective in extension) AFFECT FLEXION AND EXTENSION EQUALLY

WHITESIDE BALANCING TECHNIQUE Popliteus tendon Lateral collateral ligament Posterolateral corner capsule Illiotibial band

Tight in extension only IT band (is parallel to joint line in flexion, so it wouldn’t make sense to release it if there is tightness in flexion) Lateral posterior capsule

Illiotibial band

Lateral posterior capsule

24% instability N=83 with >10° valgus Min. f/u: 10y Release: Lateral retinaculum and iliotibial band When necessary detaching the lateral collateral ligament and popliteus tendon from the femur 24% instability

N=35 with >10° valgus Min. f/u: 5y 0% instability !

RANAWAT BALANCING TECHNIQUE 1) TIBIA CUT FIRST 2) EXTENSION GAP BALANCING: SOFT TISSUE RELEASES 3) FLEXION GAP BALANCING: ADJUST FEMUR CUTS

EXTENSION GAP BALANCING Release of posterolateral capsule Pie-crusting of the iliotibial band

FLEXION GAP BALANCING Adjust external rotation of femur cutting block based on lateral and medial gap

POTENTIAL DOWNSIDE OF FLEXION GAP BALANCING BY ADJUSTING FEMUR CUTS Anterior femur notching - as you adjust the position of the cutting block based on posterior gap Patella maltracking - as you rotate the cutting block to make the medial and lateral flexion gap equal. - In a valgus knee that shouldn’t be a problem as you would externally rotate the block to make the medial and lateral flexion gap equal. External rotation might actually improve patella tracking. - In a varus knee that might be a problem as you would internally rotate the cutting block to make the medial and lateral flexion gap equal. Internal rotation of the femur component however may cause problems with patella tracking.

WATCH OUT FOR PERONEAL NERVE FUNCTION !!! POST-OP WATCH OUT FOR PERONEAL NERVE FUNCTION !!!