
Chandana R. Karunathilaka
General Sir John Kotelawala Defence University, Sri LankaTitle: Balancing the Valgus knee and avoiding pitfalls during total knee arthroplasty
Abstract
Valgus deformity of the knee is mainly bony
and soft tissue related. Bony Factors include the distal femur lateral condyle
distortion with hypoplasia, a defective lateral tibial plateau with hypoplasia
and patella malalignment. It results in soft tissue contracture in the lateral
aspect of the knee and stretching of soft tissues on the medial side. Prior to
surgery clinical and radiological assessment of deformity in standing and
supine, varus and valgus deformity, and presence of posterior and lateral
osteophytes are important. The femoral epicondylar line is used as the
reference point with an intramedullary jig. It is advisable to take in 3° of
valgus in relation to the anatomical axis when performing the distal femoral
cut. Femoral resection should be no more than 10 mm in the medial condyle
(usually 7–8 mm). The Tibial bone cut should be 90° to its longitudinal axis
and allow 3–5°posterior slope using an extramedullary rod. The depth of the
resection should be limited to 6–8 mm in the medial compartment. The soft
tissue release and bone cuts aim to achieve a rectangular extension gap.
Minimal exposure on the medial side, removal of posterior osteophytes, and
posterior lateral release of the joint capsule along the margin of the tibial
plateau would help to achieve a reasonable extension gap. For further advanced
release pie crusting of popliteus, pie crusting of lateral collateral ligament,
and pie crusting of the IT band can be considered. External rotation of the
femoral component is important in preventing patellar femoral maltracking. During
the trial, varus-valgus stability is assessed in extension, mid-flexion, and
patella tracking with the trial implant. Post-operative complications include
tibiofemoral instability, residual valgus deformity, restricted range of
motion, wound dehiscence, residual valgus deformity, and peroneal Nerve Palsy.
Biography
Chandana Karunathilaka
is a senior lecturer in surgery at the Faculty of Medicine, Sir John
Kothelawala Defence University- Sri Lanka. He is qualified with MBBS, MS(SL),
MRCS(Eng), MCh (Trauma & Orthopaedic)-Edinburgh. He works as a
Consultant Orthopaedic & Trauma Surgeon at University Hospital- Sir John
Kothelawala Defence University Sri Lanka.