The subvastus approach is preferable for many total knee arthro-plasties,56 and is used by the senior author in 80% of cases. The subvastus approach should be avoided in situations that may make patellar eversion difficult, such as with previous lateral compartment scarring (tibial osteotomy), obesity, and patients with a prior medial arthrotomy. With a subvastus approach, the deep fascia of the thigh overlying the vastus medialis is incised in line with the skin incision. using blunt dissection, this fascia is elevated off the vastus medialis obliquus (VMO). The inferior edge of the vastus is identified and lifted off the intermuscular septum using blunt dissection. The vastus medialis muscle belly is then lifted anteriorly. While under tension, the transverse tendinous insertion to the medial capsule is cut at the level of the midpatella, leaving the underlying synovium intact.
The arthrotomy is then performed vertically adjacent to the patella and the patellar tendon. The fat pad is incised at the medial edge to minimize bleeding and is not excised unless redundant. The patella is then carefully everted and dislocated as the knee is maximally flexed to provide generous exposure of the distal femur. If the patella is difficult to evert, a partial lateral release can be performed here for the heavy patient or the valgus leg with subluxat-
ing patella. The patella insertion device can be placed on the patella to facilitate eversion.
Preliminary proximal release of the tibial soft tissue is performed and should extend to the posteromedial corner of the tibia. All osteophytes are removed to identify true bony landmarks and dimension. If a marked deformity is present, further soft tissue release may need to be performed prior to making the bone cuts. However, this can usually be best titrated once the trials are in place.
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