CHAPTER 27 Steven H. Stern 1. Osteoarthritis knee 2. Rheumatoid arthritis knee 3. Post-traumatic arthritis knee 1. Active knee infection (absolute) 2. Neuropathic joint (relative) 3. Unsatisfactory soft tissue envelope 4. Marked ligamentous insufficiency (requires constrained knee prosthesis) 5. Dysfunctional extensor mechanism 1. Knee radiographs, including standing anteroposterior (AP), lateral, and skyline views 2. Appropriate medical and anesthetic evaluation 3. Document status of preoperative neurovascular examination 4. Assessment of preoperative mechanical axis (Fig. 27–1). 1. The patient is placed supine on the operating room table. 2. All pressure points should be padded. 3. The procedure can be done with general, epidural, or long-acting spinal anesthesia. 4. Routine orthopaedic surgical instrumentation should be available. In addition, the specific instruments and cutting guides unique to the prosthesis to be implanted should be available. 1. If at all possible, prior vertical incision should be incorporated into the current skin incision. Transverse incisions may be crossed at a perpendicular angle. 2. The preoperative arc of motion should be assessed prior to the procedure with special attention to any flexion deformity (inability to fully extend the knee both actively and passively). Extra bone may need to be resected from the distal femur in the event of a fixed flexion deformity. 3. The tourniquet should be placed as proximal as possible on the thigh in order to minimize any infringement on the surgical field. In a patient with significant peripheral vascular disease, or status post bypass surgery, consideration may be given to performing the surgery without tourniquet control. 4. Intravenous antibiotics appropriate for the hospital’s bacterial flora should be administered prior to tourniquet inflation. 5. A “quadriceps snip” (“rectus snip”) can be used in knees where exposure is difficult and eversion of the patellar hard to achieve. This is accomplished by making an oblique incision, starting from the most proximal portion of the medial arthrotomy and angled superior and lateral through the quadriceps tendon (Fig. 27–3). At the end of the surgery, this incision is closed in a standard fashion; and in most cases, normal postoperative rehabilitation can be instituted. 1. Because of the problems associated with infection, great care is taken to minimize this complication. Operating room traffic should be minimized, and preoperative antibiotics administered. 2. Ligamentous stability of the knee should be assessed prior to the procedure in order to ascertain the most appropriate prosthesis for implantation. 3. Avoid internal rotation of either the femoral or tibial components. 1. A suction-type drain can be used and normally, safely discontinued the morning after surgery. 2. Constant passive motion (CPM) machines can be employed in the postoperative period. These can be started in extension and with gradually increasing flexion, or used with an early motion protocol starting at 50 to 100 degrees the day of surgery, and progressing toward extension. 3. A compressive dressing should be placed at the end of surgery and is normally changed approximately 48 h after the procedure. 4. Assessment of the patient’s distal neurovascular examination should be made the evening of surgery. If there is evidence of a peroneal nerve palsy, the dressing should be loosened and the knee placed in a flexed position. Knees with a preoperative valgus alignment or significant preoperative flexion deformities are at particular risk for developing a peroneal nerve palsy (though this complication can occur idiopathically in any knee undergoing an arthroplasty procedure). 1. Position the patient supine on the operating room table. Place a thigh tourniquet as proximal as possible on the thigh. 2. Prepare and drape the limb in the hospital’s standard sterile fashion. Exsanguinate the limb and inflate the tourniquet. 3. Make an anterior skin incision utilizing either a straight mid-line or a medial parapatellar incision. Dissect directly down to the extensor mechanism while minimizing skin flaps. Adequate exposure of the extensor mechanism with visualization of both the proximal quadriceps tendon and distal patellar tendon should be achieved prior to performing the retinacular arthrotomy (Fig. 27–2). 4. Make a medial arthrotomy utilizing either a straight mid-line, medial parapatellar, or mid-vastus retinacular incision. The distal exposure is similar in all of these techniques with the distal limb of the retinacular incision carried along the proximal tibia medial to the tibial tubercle. Extend the retinacular incision as far proximally as necessary to achieve adequate exposure (Fig. 27–3). 5. Use a periosteal elevator to subperiosteal strip the perisoteum off the proximal medial tibia. Take care to keep this layer in continuity. 6. Evert the patella and flex the knee (Fig. 27–4). Take care not to avulse the patellar tendon. If it is not possible to evert the patella, perform a “quadriceps snip” (“rectus snip”) (Fig. 27–3). 7. Dissect the proximal tibial periosteum.
Total Knee Arthroplasty
Indications
Contraindications
Preoperative Preparation
Special Instruments, Position, and Anesthesia
Tips and Pearls
What To Avoid
Postoperative Care Issues
Operative Technique
Approach
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