In this article, Dr. Villanueva, a specialist in Traumatology, talks about how knee prostheses help to improve the quality of life of those who need them.
Knee prosthesis surgery and pain
The knee prosthesis is one of the most successful operations in modern orthopedics. A knee prosthesis should be considered when the patient has a wear of the joint, either caused by osteoarthritis, a degenerative condition, an inflammatory condition, a rheumatic or autoimmune disease or sequelae of fractures or trauma that the patient had in the past.
When that problem or that wear and tear of the joint causes pain, stiffness, limitation of function or the patient’s ability to perform or have a normal life, either work, leisure or family, is when the knee prosthesis should be considered as a solution to the pain of the joint and as an opportunity to regain quality of life. The prosthesis should not be an added problem to the one the patient already has, but should be seen as an opportunity.
What can be the causes of pain from a knee prosthesis?
The main causes of early knee revision for pain, before 2 years from the implantation of the prosthesis, are:
- Infection.
- The instability.
- Malposition of the components.
The main causes of late revision, after two years, are wear of the polyethylene of the prosthesis, loosening and instability.
A painful knee prosthesis can be produced by
- By septic or infected cause (acute, subacute or chronic or late).
- By a non-infected aseptic cause.
In the latter case, the surgeon must be able to analyze the situation of the tissues, of the soft tissues or whether there is bone loss, etc.
And in turn, he/she should know which prosthesis models are best adapted to solve the specific case of our patient and obtain the best possible result. It is essential to have a very high specialization to offer the best possible prosthesis replacement.
A failed knee prosthesis
It is not normal that a knee prosthesis hurts. It is normal that there may be some discomfort, even for weeks or months after being implanted, but after a few months, a prosthesis should not hurt. The prosthesis is placed so that the patient does not feel pain and recovers his quality of life. However, some discomfort may become normal. Some patients are affected by changes in the weather or if they make very intense efforts, such as going up or down stairs with a lot of weight, they may feel some discomfort, but they should recover from this discomfort in a natural way and without medication.
If the knee prosthesis hurts us, we should not let it go unnoticed and assume it as a pain inherent to the surgery. Consult with your specialist to find out the cause. When a prosthesis hurts, it is considered a failed prosthesis, since it is not fulfilling the function for which it was placed.
How to know why a knee prosthesis hurts?
To know why a knee prosthesis hurts, the specialist will have to analyze
- Aspects previous to the surgery (previous surgeries, vascular, neurological diseases, rheumatoid arthritis, etc.).
- Psychiatric diseases (depression, anxiety).
- Intraoperative aspects (surgical complications).
- Postoperative evolution.
Where do knee prostheses hurt?
The orthopedic surgeon of knee prosthesis will analyze the zone of pain for the diagnosis or cause of pain of the knee prosthesis.
If there is pain in extension of the knee prosthesis usually refers to the posterior area of the knee, it suggests contracture of the hamstrings.
The pain in flexion of the knee prosthesis, although it is normal in the first weeks after the surgery until the patient reaches its maximum flexion arch, but its persistence is not normal.
Knee prosthesis pain with stairs. This area of pain is related to, subluxation, wear of the prosthesis materials… Patients speak of sensations such as ‘my knee is coming out’ or ‘my knee is failing’.
Diagnosis of painful or failed knee prosthesis
After the analysis of the areas of pain, the knee traumatologist, with the pathologies or complications associated with each area, can complete the analysis for the diagnosis of pain of the knee prosthesis that hurts with
- Radiographies.
- Gammagraphies.
- Tac or other diagnostic tests of image.
- Laboratory tests if infection is suspected.