Pain, bleeding, infection, bone fractures and blood clots in the lungs and legs are possible complications of knee replacement surgery, according to Johns Hopkins Medicine. Over time, the replacement knee may also become worn or dislodged, and nerves or blood vessels injured during the procedure may lead to numbness.
Knee replacement surgery involves the insertion of prosthetic materials at the knee joint where the femur and tibia bones meet, states MedicineNet. The surgeon replaces the end of the femur with a metal shell and the end of the tibia with a plastic and metal bearing. When necessary, the physician also implants a plastic prosthetic under the kneecap to compensate for any deterioration. The surgery is intended to relieve soreness and stiffness from degenerative conditions, such as osteoarthritis, but some patients continue to suffer from chronic pain after the procedure or develop internal bleeding. If a blood clot forms in the leg, it can travel to the lungs and cause a pulmonary embolism, or blocked artery, triggering symptoms like chest pain and shortness of breath.
Depending on the patient, reactions to post-surgery pain medication can cause complications like nausea, vomiting and urinary tract infection, according to MedicineNet. Another rare complication is an adverse reaction to anesthesia, and when patients develop infections, they again face the risks of undergoing further surgery.