Total Knee Arthroplasty in Valgus knee

1. Total Knee Arthroplasty in Valgus knee H.Makhmalbaf MD Consultant Knee surgeon Mashad University

2. The Typical patient • Sever valgus deformity • Elderly woman in7th or8th decade • Has had “knock knees” • Also had patellofemoral problems • Valgus deformity progresses • Loss of lateral joint space • Attenuation of MCL

3. The typical patient • PFJ involvement & patella dysplasia on X-Ray • Patella subluxation & concave patella • Patella alta & a very thin patella • Chondrocalcinosis & calcification of menisci • Long leg film of tibia shows valgus bow

4. The typical patient • The valgus tibia is problematic if using intramedullary guide • The long leg film is necessary to template • The diagnosis is usually OA or RA • Hypermobile knee or hyperextention • In RA might have stiff knee & flexion cont.

5. Clinical features of valgus vs varus • Valgus knees tolerate significant damage • In windblown knees varus knee is more symptomatic • Varus knee should be operated on 1st • Source of deformity is also different • Medial tibial plateau is deficient & tibial joint line in sever varus in varus knees • The femoral joint line is still in 5-7 valgus

6. Valgus vs varus knee • In valgus knees, is from the femur • The tibial joint line usually in neutral • The femoral joint line is in marked valgus • Deformity due to hypoplasia of lat.femoral condyle • Both distally & posteriorly • The tibial defect in valgus is contained

7. Variants of valgus • Based on degree of deformity • Status of MCL, osseous deficiency & • The amount of release must be performed • Variant I: mild & correctable deformity • Variant II: greater deformity ,intact soft tissue • Variant III: stretched MCL, Marked bone loss & deformity & lateral contracture

11. Type of prosthesis • In variant I: P CR or PS may be used • In variant II: may require a PS implant • Invariant III: a PSC (constrained) should be used • Complete set of instruments if preferred

12. Lateral femoral condyle hypoplasia • Is present in sever valgus deformity • Exists both distally & posteriorly • In distal femoral resection don’t cut to the defect • The deficiency must be augmented • If not, causes large extension gap • And elevation of joint line • And mid-flexion laxity, distorting kinematic

13. The angle of DF cut • 5 degree is preferred • 7 degree cut is better for balance but? • 5o or less to overcorrect the deformity • Less tension on MCL on WB • But needs more lateral release • Distal metaphyseal bow • More medial point of entrance in the notch

14. Balancing the knee in flex.& extension • Create symmetric flexion extension gaps • Valgus knees could be balanced in flexion & extension independently • In flexion the tissues are not tight • Nor the medial tissues are lax in flexion • Draw Whiteside line & transepicondylar ax • In sever valgus int rotation of femoral component is necessary

15. Flexion extension balance • Lateral release, after bone cuts • Put spacers, varus & valgus tests • Inverted cruciform release • LCL, poplliteal, & Biceps tendon release • PS in sever valgus & CR in mild one • Surgical approach

16. Summary • Associated with PFJ disease • Lat femoral condyle hypoplasia • Medial laxity, a valgus tibial bow • Conservative bone cuts • Cruciform release of ITB & capsule • Protect peroneal nerve • PS or CR knee

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