Introduction The lateral parapatellar approach provides direct access to the pathological area in a valgus knee deformity and allows sequential titrated release of contracted lateral soft tissues during total knee arthroplasty.
Step 1: Preoperative Planning Differentiate the flexible and fixed components of the valgus deformity by clinical and radiographic examination.
Step 2: Expansile Lateral Arthrotomy Open the knee joint from the lateral side by coronal z-plasty of the lateral retinaculum, oblique lateral tenotomy of the quadriceps tendon, and iliotibial band release.
Step 3: Quadriceps Snip and Joint Exposure Perform a quadriceps snip and expose the knee joint.
Step 4: Tibial and Distal Femoral Cuts Make proximal tibial and distal femoral cuts in appropriate alignment.
Step 5: Extension Gap Balancing A rectangular extension gap is the goal.
Step 6: Flexion Gap Balancing Determine the femoral component size and femoral rotation, and balance the flexion gap.
Step 7: Component Fixation Confirm tibial rotational alignment, fix the components, and assess patellar tracking.
Step 8: Prosthetic Joint Closure Perform closure of the prosthetic joint with expanded lateral structures.
Results Between 2003 and 2009, thirty-two knees with clinical valgus deformity of >10° underwent total knee arthroplasty with an expansile lateral arthrotomy technique11.
Pitfalls & Challenges
The lateral parapatellar approach provides direct access to the pathological area in a valgus knee deformity and allows sequential titrated release of contracted lateral soft tissues during total knee arthroplasty.
Valgus deformity is less commonly encountered but more technically challenging than varus deformity1-3. Typically, the intraoperative challenge is to obtain optimal tibiofemoral gap balancing that corrects the deformity without producing instability and to achieve optimal patellofemoral balancing. The standard technique is medial arthrotomy and lateral release with the inside out “pie-crusting” technique, which is suitable for “clinical valgus” deformities of <20°2 …
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