Causes of pain after TKR
I have come across a few patients who suffer from pain after total knee replacement. Hoping that their pain will disappear immediately or settle down following their knee surgery, they opt for a total knee. However sometimes their expectations are belied when pain persists. Pain after the first month is a definite cause of worry. In the post op period, excess pain is because of inadadequate analgesia. A standard surgical approach in which the quadriceps muscle is cut through a big 12 inch scar takes a long time to heal and such patients have more pain than those patient who undergo knee replacement through shorter incisions. Other causes are septic and aseptic loosening
Infection is the most dreaded complication after any joint replacement including a TKR. The consequences of an infection are disastrous needing removal of the infected prosthesis, cement and a revision knee replacement. Bone loss may occur and the second operation is more risky than the first. It is therefore important to carefully choose the surgeon and the hospital. Infection can occur per-operatively or post-operatively. They can spread from the skin,atmosphere oral cavity, urinary tract or the gut.
Loosening occurs due to an incorrect placement of the original prosthesis, inadequate cementation or due to wear particles.
Infectious loosening can be diagnosed by knee joint aspiration, blood tests, x rays and a bone scan. Specimens need to be sent to obtain the nature and sensitivity of the organism. Treatment consists of removal of prosthesis and cement, implantation of cement spacer followed by a course of intravenous antibiotics. When the infection is quiescent and joint aspirate is negative a revision knee replcament can be done. This procedure is called a two stage revision and is the gold standard.
When there is no hope of the infection settling down, an arthrodesis may be necessary in which movement is abolished at the knee.
When it is certain that infection is not the cause of loosening, then one has to consider aseptic loosening as the cause of pain. Again revision knee replacement may be necessary.