Indications of a potentially difficult exposure (Figure 60.1) during revision surgery should be sought preoperatively by considering:

Excellent exposure to the knee can be safely obtained by following a sequence of stepwise maneuvers described in this chapter, which consists of:

Perioperative—Consider using intraoperative blood salvage systems, tranexamic acid, tourniquet, Foley catheterization, intraoperative fluoroscopy or x-rays.

Extras—Consider a small blade saw, flexible osteotomes, and cerclage wires (for fixation of a tibial tubercle osteotomy).

A midline incision (unless contraindicated by prior surgeries) with a medial parapatellar arthrotomy with subluxation of the patella is most commonly used. The sub- or midvastus and lateral parapatellar approaches are less extensile and therefore avoided for revision surgeries.

Skin considerations—Careful evaluation of the skin for lesions, wounds, and prior incisions is mandatory. Generally, the cutaneous blood supply is from medial to lateral; therefore, the lateral-most acceptable longitudinal incision should be utilized. This also minimizes disruption of the lymphatic system, which drains from lateral to medial. A skin bridge of 7 cm is usually sufficient, and crossing incisions should be made at right angles (Figure 60.2). In complex cases, consultation with a plastic surgeon should be considered where soft tissue expanders or flaps may be necessary.

Physical examination—Patients with notable stiffness are most likely to have a difficult exposure. Examination of passive range of motion as well as laxity in the coronal and sagittal planes and extensor mechanism function are paramount.

Radiographs—Evaluate the presence of deformity, bone quality, patella position, and current implanted components. A stemmed, cemented tibial component may prompt the use of a tibial tubercle osteotomy to facilitate implant and cement removal (Figure 60.3). Furthermore, review of prior operative reports is recommended to know exactly what components are implanted. Plan ahead to have the necessary instruments and parts needed during the revision surgery.

Place the patient in the supine position with supports according to surgeon preference, and drape a wider-than-usual field.

Superficial exposure—Create full-thickness skin flaps through the planned incision. The correct plane of dissection can be found using the patella as a deep landmark, applying traction to the soft tissues during dissection with the knee in flexion, and extending the dissection proximal to the scar tissue to find the undisturbed soft tissue planes above the quadriceps muscle.

Medial parapatellar arthrotomy—Locate the medial aspect of the patella, patellar tendon, and tibial tubercle by palpation. Sutures from prior arthrotomy closure may help guide the trajectory of the arthrotomy. Sharp dissection may be used for the lower half of the arthrotomy followed by use of Mayo scissors to split the tendon proximally.