PREOPERATIVE DIAGNOSIS: Severe varus osteoarthritis of
the right knee.
POSTOPERATIVE DIAGNOSIS: Severe varus
osteoarthritis of the right knee.
OPERATION PERFORMED: 1. Right total knee replacement using
Smith
& Nephew Journey components.
A
size 6 femur was used with a size 6
tibial
tray, a 15-mm bicruciate stabilized
polyethylene
insert and a 35-mm
cemented
polyethylene patellar button.
2.
Medtronic optical-assisted computer navigation.
anesthesia: Regional.
PROCEDURE
IN DETAIL: After the smooth
induction of anesthesia, the patient was given intravenous Ancef antibiotic
prophylaxis. The right lower extremity was prepped and draped in the usual
sterile manner. After exsanguination with a sterile Esmarch bandage, a
previously placed pneumatic tourniquet was inflated to 375 mmHg.
An
incision was then made starting at the superior pole of the patella and
extending down to the tibial tubercle. Blunt dissection was carried out. A
limited medial arthrotomy was performed. The proximal border of the tibia was
subperiosteally exposed and the medial 1/3 of the patellar ligament was
released. Portions of the retropatellar fat pad were then sharply dissected
from the knee joint. The patella was partially everted and a limited cut was
made paralleling the extensor mechanism.
Portions
of the ACL, PCL, and medial and lateral menisci were sharply dissected from the
knee joint. Two parallel pins were placed in the mid shaft of the femur and the
tibia. The Medtronic optical-assisted computer navigation system was assembled,
calibrated, and preoperative anatomical landmarks were obtained as per
protocol. The patient was noted to have a 10-degree flexion contracture and a
6-degree varus deformity. The Medtronic optical-assisted navigation system was
used to correct this deformity throughout the procedure.
At
this point, a standard distal femur cut was made, keying off the low point on
the medial femoral condyle. Twelve millimeters of bone were removed. The bone
edges were smoothed and navigation was used to confirm alignment.
At
this point, the tibia was subluxed anteriorly. The extramedullary alignment jig
was positioned in place, paralleling the anterior border of the tibia. Bone was removed, keying off the low point of
the medial tibial plateau. Laminar spreaders were placed in the knee. The
remains of the ACL, PCL and medial and lateral menisci were sharply dissected
from the knee joint. The bone edges were smoothed. A spacer block with an alignment jig was now
used to confirm the knee was balanced in extension as our tibial cut was
exactly perpendicular to the anterior border of the tibia. After sizing was
carried out, the appropriate femoral cuts were made. Spacer blocks were used to
confirm the knee was balanced in both flexion and extension.
The
tibia was subluxed anteriorly. The size 6 tibial tray was centered over the
tibial tubercle. Peg and keel cuts were
made. The tray fit nicely. The central peg of bone was removed from the distal
femur with a high speed drill. Various inserts were used to confirm that the
knee was balanced in extension and in flexion. A final patellar cut was
made. A 35 lollipop was placed in the
proximal medial position. Peg cuts were
made. The patellar button was trialed. The knee was placed through range of
motion and the patella tracked nicely down the center of the femoral trochlea
throughout the range of motion using a no-hands technique.
All
trial components were removed and while cement was being vacuumed premixed, the
wound was vigorously irrigated with a pulsatile lavage system and packed with
Kerlix soaked in peroxide. In sequential fashion, the tibial tray and femoral
component were cemented in place. A trial insert was placed over the tibia. The
knee was placed into extension to compress the bone. It was then brought back to 90 degrees, at
which point, excess cement was removed. The knee was placed back into extension
to allow the cement to harden. After the patellar button was clamped in place,
the tourniquet was released. The knee was kept in extension to allow for the
cement to harden. Meanwhile, the tourniquet was released. The wound was
irrigated. Any residual protruding synovium was trimmed and closed with #2
Vicryl.
The
trial insert was then removed once the cement hardened. The knee was inspected
and any excess cement was removed and any loose tissue was excised. The wound
was again irrigated. The tray was inspected and the real insert was now secured
in place. Final range of motion was
noted to be a 2 degrees of hyperextension with the knee in 1 degree of valgus.
One hundred degrees of flexion was obtained with excellent varus/valgus
stability throughout the range of motion.
A
drain was now placed in the lateral gutter and brought out through a separate
stab wound. The wound was again aggressively irrigated. The medial retinaculum
was closed with #2 Vicryl. The subcutaneous tissue was closed with 2-0 Vicryl
and the skin was closed with staples. The wound was washed and dried, and a
sterile compression dressing was applied. The knee joint was then injected with
20 mL of Naropin, 6 mg of Decadron, 0.2 mL of epinephrine, 500 mg of Zinacef
and 10 mg of morphine. The drain will be clamped for several hours to allow the
fluid to seep into the soft tissue.
After
anesthesia was reversed, the patient was brought to the recovery room, having
tolerated the procedure well without complications.
Sponge count and needle counts were correct. Estimated blood
loss was 150 mL. Tourniquet time was approximately 50 minutes.
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