PHYSICA ZUK SURGICAL TECHNIQUE Preoperative Planning and Patient Preparation
PREOPERATIVE PLANNING
In UKA, varus/valgus alignment is determined by the total thickness of the prosthetic unicompartmental components. The amount of tibial bone resection is variable while the amount of distal femoral bone resection is constant.
Take standing weight-bearing A/P, lateral, and skyline radiographs of the affected knee.
In this technique, the tibia is resected first and the femoral resection is based of the tibial cut.
A long-standing A/P radiograph showing the center of the femoral head, the knee, and as much of the tibia as possible (preferably including the ankle) may also be beneficial to determine the mechanical axis. TECHNIQUE TIP. It is important to avoid overcorrection. An additional radiograph while stressing the limits of the collateral ligaments may be helpful in assessing the maximum correction.
When evaluating the patient and planning for the procedure, consider TKA if:
• Degenerative changes are present in the contralateral compartment and/or the patellofemoral joint; • The ACL is deficient; • A significant flexion contracture exists; • Slight under correction is not attainable; • A significant overcorrection is likely with a varus stress; • There is an existing valgus or varus deformity › 15°.
PATIENT PREPARATION
With the patient in the supine position, test the range of hip and knee flexion. If unable to achieve 120° of knee flexion, a larger incision may be necessary to create sufficient exposure.
Wrap the ankle area with an elastic wrap. Do not place bulky drapes on the distal tibia, ankle, or foot.
A bulky drape in this area will make it difficult to locate the center of the ankle, and will displace the Tibial EM Guide, which may cause inaccurate cuts. Before surgery, mark the tibial crest, the tibial tubercle, and the second metatarsal.
6 Surgical Technique PHYSICA ZUK
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