Painful hip replacement: a disabling condition that can discourage those who have already undergone surgery in hopes of regaining their joint function. What are the causes of this symptomatology and what can be done about it?
When the joint suffers severe damage or progressive wear and tear (coxarthrosis), hip replacement is necessary to restore normal joint mobility and eliminate painful symptoms.
Although it is a fairly invasive procedure, the results are, in most cases, more than satisfactory. This is mainly due to improved prosthetic designs, increasingly biocompatible materials and new minimally invasive surgical techniques.
It may happen, however, that even once the postoperative phase has passed, joint pain persists: the patient is thus faced with a painful hip replacement.
Painful hip replacement: when not to be alarmed
The hip is a joint that allows many movements in planes and is less innervated than the knee. This means that, the postoperative phase, is characterized by less pain and the absence of stiffness problems, which are frequent with knee replacements.
In fact, a hip replacement surgery patient can return to walking, with only the help of crutches, as early as a few days after surgery.
On the other hand, there are postoperative cases characterized by more pain, often due to the presence of hematomas (collections of blood) around the joint; in fact, it is normal for there to be some bleeding from the bone “prepared” to receive the prosthetic components.
This type of pain should not be frightening: in the totality of successful surgeries, it gradually disappears, giving way to proper functional recovery.
If, on the other hand, normal postoperative pain is succeeded by pain symptoms with different characteristics, then it is fair to think that the prosthesis may have some problem.
How to tell if it is painful hip replacement
To understand whether we are dealing with a painful hip replacement that needs proper investigation, we need to pay attention to some signs:
- The pain manifests as a burning sensation or sudden twinges;
- symptomatology does not improve when taking painkillers;
- the problem persists beyond four to six weeks.
However, we need to be very careful: before we can conclude that it is indeed a painful hip replacement, we need to be able to rule out that an infection is in progress.
Painful prosthesis or infected prosthesis?
The fact that the situation worsens over time instead of improving could mean that we are in the presence of an infection.
Infected prosthesis is definitely the most dreaded complication that a hip replacement can present.
The first thing to assess in these cases is wound healing: a wound that has had difficulty closing, with serous discharge, reddened and sore, may be one of the first signs of infection. However, infections can also be characterized by bacteria with low virulence and progress in a more insidious and chronic manner.
By performing blood tests and possibly ultrasound sampling from the joint, it will be possible to rule out this rare but extremely dangerous complication.
Prosthetic infection can be successfully treated but it is very important to recognize it as soon as possible-that is why this is definitely the first investigation to complete.
Once prosthetic infection is ruled out, one can proceed to look for the causes of the painful hip replacement.
Finding the causes of a painful hip replacement
As we have already mentioned, joint pain is the main reason that directs us to perform prosthetic hip replacement.
While it is normal that pain symptomatology may be present in the postoperative stages, its persistence and failure to recover function in the weeks following surgery is a problem that will need to be investigated and resolved.
Prosthetic mobilization
Aside from the infectious risk, the main cause of hip replacement failure is the failure of the prosthetic components to weld to the bone.
During surgery, the acetabular cup and femoral stem are stabilized by preparing the bone so as to allow mechanical “interlocking”; this interlocking should be such as to allow movement and joint loading.
Over the months, this mechanical stability will become more and more solid and stable, thanks to the integration of the components to the surrounding bone; in fact, our organism is able to build real bonds with the surface of the prosthesis, through so-called bone bridges.
After a thorough clinical examination to identify the site of the pain, one will then need to analyze the radiographic images (and possibly a CT scan) to determine if there are signs of a prosthetic failure to bond, termed prosthetic loosening.
This loosening usually occurs after a shorter or longer period of time after the prosthesis is integrated with the bone. Thus, even years later, the patient may complain of a progressive onset of pain, resulting in limitation of his or her activities.
Prosthetic loosening is the main reason for prosthetic revisions. But the causes may also be others.
Muscle pain
Other important causes of a painful prosthesis may be ileo-psoas muscle conflict or a hip muscle deficit.
The ileo-psoas syndrome
That of ileo-psoas muscle conflict with the anterior border is a cause that can reach up to 2% of total cases.
The iliopsoas is an internal hip muscle that passes anterior to the joint capsule and acts by flexing, abducting, and extra rotating the femoral head. Sometimes, due to the anatomy of the acetabulum, the prosthetic cup does not disappear completely inside the bone, causing irritation to this very muscle.
In these cases, the pain is typically anterior and appears during activation of the iliopsoas muscle, that is, in active anterior flexion of the hip on the pelvis.
This symptomatology is easy to resolve: with a simple arthroscopy, a detension of the muscle is performed, allowing the immediate disappearance of pain and a quick functional recovery.
Muscle deficiency
Another cause of painful prosthesis may bepostoperative insufficiency of the gluteal muscles. In fact, it may happen that during surgery, a detachment of the gluteus medius and gluteus petit muscles occurs, or inflammation of their natural site (the trochanter) occurs later.
This condition causes the patient to experience difficulty in abandoning the second crutch with a consequent inability to have independent ambulation.
In most cases, however, appropriate physical therapy and rehabilitation will be able to resolve the deficit or inflammation of the gluteal muscles.
The surgical revision
As we have seen, in the case of muscle problems such as ileo-psoas syndrome or a deficit in the gluteal muscles, there will be absolutely no need for surgery. If, on the other hand, the cause of a painful hip replacement is attributable to an infection or a prosthetic weld failure, then a surgical revision of the hip replacement will need to be planned.
Do you have a painful hip replacement problem and wish to find a solution? Do not hesitate to contact me.
