The use of certain special surgical instruments is suggested in the performance of this surgery.
Review of the use and handling of these instruments is important. The alignment and cutting
jigs should be checked prior to surgery. Bent or damaged instruments may lead to improper
implant position and result in implant failure.
Proper cleaning and preparation of the bone surfaces is important for obtaining prosthesis
fixation. Bone excision should be limited to the amount necessary to accommodate the
implants. Excessive bone removal or use of multiple pins to secure instruments may result in
mechanical disturbances and bone resorption with subsequent failure of the procedure due
to loosening or deformation of the implant. When preparing bone surfaces and positioning
the components, proper alignment must be ensured.
Prior to closure, the surgical site should be thoroughly cleansed of bone chips, ectopic bone,
bone cement, etc. Foreign particles at the metal/plastic articular interface may cause excessive
wear. Ectopic bone and/or bone spurs may lead to dislocation or painful and restricted
motion. Range of motion should be thoroughly checked for improper mating, instability or
impingement and corrected as appropriate.
Postoperative
Strict adherence by the patient to the surgeon's instructions and warnings is extremely
important. Accepted practices should be followed in postoperative care. Postoperatively, the
patient should be cautioned to limit his/her activity level to protect the replaced joint from
unreasonable stresses. The patient should be released from the hospital with complete
written instructions and warnings regarding exercises and therapies and any limitations on
his/her activities. Periodic follow-up including x-rays are recommended for close comparison
with previous post-op conditions to detect long-term evidence of changes in position,
loosening, bending, or cracking of components. If evidence of one or more of these
conditions is discovered, patients should be closely observed, the possibilities of further
deterioration evaluated, and the benefits of early revision considered.
ADVERSE EVENTS AND COMPLICATIONS
The following are generally the most frequently encountered adverse events and
complications in total knee arthroplasty:
General
1.
Early or late loosening, tibial subsidence, bending, cracking, fracture, deformation, or
wear of one or more of the prosthetic components, often related to factors listed under
WARNINGS AND PRECAUTIONS. Loosening may also occur due to improper fixation or
positioning.
2.
Early or late infection which may require removal of the implant and a subsequent
arthrodesis.
3.
Pain, dislocation, subluxation, flexion contracture, decreased range of motion, or
lengthening or shortening of the leg, caused by improper positioning, looseness or wear
of components.
4.
Excessive wear of the polyethylene components due to intraoperative damage to the
femoral component, loose cement and/or bone fragments, and/or high patient activity
levels or weight.
5.
Fractures of the tibia or femur. lntraoperative fractures are usually associated with revision
surgery, deformity and/or severe osteoporosis. Postoperative fractures are usually stress
fractures. Fractures can be the result of defects in the cortex due to multiple pin holes,
prior screw holes, misdirected reaming, and/or inadequate or maldistribution of bone
cement.
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