Skin incision

Blood supply to the anterior aspect of the knee is predominantly derived from the medial side, and it travels from deep to superficial layers. Hence, if there are many previous incisions, the most lateral one should be utilized, and full thickness skin flaps should be developed, as well as excision of the scar tissue. Transverse scars should be transected at a perpendicular angle to prevent skin necrosis. Patients with multiple scars and densely adherent skin may require a preoperative consultation with a plastic surgeon.

Capsular approach

The workhorse approach to the knee is the medial parapatellar capsular incision. When performed associated with an accurate anterior and posterior intra‐articular synovectomy, it provides an adequate exposure for most revision TKAs.⁸

Using extensor mechanism tenolysis and scar removal technique, eversion of the patella and removal of components is readily accomplished for the vast majority of patients.⁷ After that, the patella inversion method affords adequate exposure in most patients without violating the extensor mechanism.⁴

Mobilization of the extensor mechanism

If at this point in the procedure the exposure is inadequate, an extensive exposure of the knee is required to increase patellar excursion while maintaining the function of the extensor mechanism. It is a critical step, and it should aim to minimize the risk of patellar tendon disruption, quadriceps tendon rupture, patellar crepitus, and soft tissue impingement, periprosthetic patella fracture, patellofemoral instability, and osteonecrosis of the patella. The decision to extend the incision proximally, distally, or in combination should be determined on an individual basis.

Proximally, relaxation of the quadriceps tendon can be achieved by a QS.⁵,¹¹ Technically easier, it does not require an alteration in the postoperative physical therapy and it shows similar clinical outcomes as those achieved using an isolated medial parapatellar approach (MPA). However, some studies have demonstrated an increased risk of implant malalignment in primary TKA.¹² An extensive MPA increases the mobility and excursion of the patella to the same extent as the QS technique, and it is theoretically safer in terms of preservation of quadriceps tendon integrity.⁹

The V‐Y modified quadricepsplasty (QP) is rarely indicated given the risk of postoperative extensor lag. Notwithstanding the possible extension lag, Zhamilov et al. conclude that QP is as effective as QS when extensile exposure is required and may be used safely, although weightbearing is delayed postoperatively.³ In general, however, it is considered only when a TTO is contraindicated and there is severe stiffness. Distally, the exposure can be improved by a TTO, which gives the greatest degree of exposure and it is useful in patients with stiff or ankylosed knees, in cases of patella baja or when a well‐fixed cemented tibial stem should be removed. TTO should be considered the gold standard in extensile exposure, but it is a technically demanding procedure and also associated with some complications if it is done without a strict technique.