PREOPERATIVE DIAGNOSIS: Right knee, severe inflammatory arthritis.
POSTOPERATIVE DIAGNOSIS: Right knee, severe inflammatory arthritis.
PROCEDURE: Right total knee arthroplasty and right knee synovectomy.
ANESTHESIA: Epidural plus spinal.
IMPLANTS: Osteonics Scorpio posterior stabilize #9 femur, #7 tibia, 8 mm posterior stabilized non-crosslink spacer and #5 patella.
PROCEDURE IN DETAIL: After obtaining informed consent, ….. is brought to the operating room whereupon a smooth induction of spinal and epidural anesthetic was performed by Dr. …... The patient was positioned in supine fashion on the operating room table and all bony prominences were well-padded. A bump was placed under the left hip and a gram of Kefzol was given intravenously. A Foley catheter was placed and a tourniquet was placed on the right proximal thigh. The right lower extremity was then prepped and draped in standard sterile fashion including an alcohol pre-prep. After exsanguination of the limb with an Ace wrap, the tourniquet was inflated to 275 mm of mercury.
A longitudinal incision, approximately 5 inches long, was made about the anterior aspect of the knee centered on the inferior pole of the patella. The skin and subcutaneous tissues were dissected sharply down to the level of extensor fascia and this was elevated medially and laterally to allow visualization. A median peripatellar incision was made starting just medial to the tibial tubercle and extending up to the medial aspect of the patella and then curving slightly laterally to approximately the 2:30 position at which point the incision took a sharp turn at 90 degrees into the VMO in line with its fibers. The patella was then subluxed laterally but not everted as it was not throughout the entire case. A medial slide was carried out using a Bovie and a Cobb with care taken to protect the medial collateral ligament. The posterior patellar fat pad was resected (approximately 75%). This was done sharply with a knife. The notch was débrided of the anterior and posterior cruciate ligaments using a Bovie cautery on cutting. Z retractors were placed medially and laterally about the knee and after the notch osteophytes were débrided with a rongeur, the femoral entry hole was made just anterior to the notch. A sword was placed with a distal femoral cutting guide using the minimally invasive Osteonics instrumentation. A 10-mm distal femoral cut was made and good bony section was noted with a slight bridge between the medial and lateral femoral condyles. Then using posterior reference to technique, the femur was sized to a 9 component. This seemed almost too wide in medial and lateral direction but a size 7 component clearly would have produced notching even with placing the component slightly anterior. Therefore, the size 9 was selected. Using the minimally invasive four-in-one cutting guide, the cuts for the size 9 femoral component were made using approximately 3 degrees of external rotation using the intercondylar axis as a reference. Once the cuts were complete we were happy with the appearance of the distal femur. Attention was then turned to the patella. The patella was then sized to a size 22 mm in thickness. Using the patellar cutting guide, an 8 mm cut was made so the patella was now 14 mm in thickness. It was sized to a size 5 and the drill holes for the trial component were created. The trial femoral component was placed and the trial patellar component was placed and both found to fit well. The patellar component was removed and attention was returned to the tibia. The Z retractors were removed and a single-prong pickle fork retractor was placed posteriorly and at Gerdy’s tubercle for exposure to the tibial plateau. A standard 0 degree posterior slope cut was made in neutral varus valgus with 2 mm being taken off the low point of the low side (medial). The tibial resection was judged to be adequate and a trial size 9 tibia was placed. This was found to be slightly oversized and therefore a size 7 was selected. This fit very well and an 8 mm posterior stabilized spacer was placed and all the trial components were reduced and the knee was taken through range of motion. Excellent stability of the medial and lateral collateral ligaments in flexion and extension as well as excellent tracking of the patella were encountered. The tibial perforation was then finished using the same cutting instruments. The trial components were then removed after drilling the holes for the femoral condyles and the knee was copiously irrigated with normal saline. The entry hole in the distal femur was plugged using bone graft from the distal femoral cuts. The final components were then cemented in the following order:
patella, tibia, femur. After removal of excess cement, the final tibial tray was placed and the knee was brought to full extension while the cement hardened. Once the antibiotic cement provided by the Osteonics Company had hardened, the knee was again taken through range of motion, and stability and range of motion were found to be excellent. The knee was probed one further time to make sure that no excess cement was left behind and then closed in layers over a ConstaVac drain. The extensor fascia was closed using #1 Vicryl in a simple interrupted fashion. The subcutaneous fascia was loosely closed using #1 Vicryl and the subcutaneous layer was closed using interrupted 3-0 Monocryl suture in a simple varied fashion. Staples were placed at the level of the skin. A sterile dressing was applied with a compressive wrap from the toes to the thigh. The ConstaVac reservoir was attached and activated and the tourniquet released for a total time tourniquet time of 115 minutes.
IV fluids were 1,900 mL. Urine output was 300 mL. There were no intraoperative complications. The bony resection specimens were sent to the pathologist.
Postoperatively, the plan will be for weightbearing as tolerated with physical therapy and continuous passive motion (CPM) to begin on the day of the operation. She will receive Kefzol, and the epidural PCA, and the ConstaVac and the Foley catheter will be left in place for 24-48 hours. Coumadin and foot pumps will be used for DVT prophylaxis.