Dr. Sebastian Garcia Ramiro
Specialist of orthopaedic and traumatology, coordinator of osteoarticular infection unit.
Hospital Clínic of Barcelona, Spain.
The wide range of preformed spacer includes 24 variants. 4 types of stem combinable with 3 sizes of head and 2 options of antibiotic.
The preformed spacer for knee includes 7 variants: 3 with Gentamicin and 4 with Vancomycin + Gentamicin
Dr Garcia, how long have you been dealing with osteo-articular infections?
I deal with this pathology since when I finished my studies, i.e. 30 years ago.
In relation to the treatment of hip, knee and shoulder prosthetic infection, how many patients are treated per year in your department?
Around 80-90 patients.
Today the standard treatment of care of a chronic infection of a prosthesis requires the removal of the prosthesis itself and the use of antibiotic-loaded PMMA spacer. In the last 10 years you have used the preformed spacer of Tecres, and between hip and knee spacers, you have implanted about 100.
Which are the results and the comments of the patients?
The results are extremely satisfactory from the medical point of view as the spacer favour the second stage surgery thanks to the fact that they maintain the extremity length and this is very important to make easier the positioning of the new prosthesis: moreover we think that the use of a preformed spacer may decrease the operatory time, which is important for the patient: as regards the patient, the feeling is that there is a higher comfort as it is allowed a better indipendence compared to any other situation, as for example a Girdlestone situation.
Hip: how do you decide the size of the head?
We do make a pre-op planning with templates of the spacer, which are available, nonetheless during the intervention, before positioning the spacer, the spacer trial is used to check the good fitting of the head.
When is it used the short stem spacer and when the long stem one?
We normally use the short stem spacer, even though the situations we encounter are very different, such as when there is an important loss of bone stock, when instead we need to cut open bone windows or to perform osteotomies to remove the infected prosthesis, then we use the long stem spacer which bypasses the window or the osteotomy.
Is is advisable the neck cementation?
We perform the neck cementation when we have a feeling of instability of the spacer. When instead the spacer seems to be well fixed, then we prefer not to use cement. We always perform a test of stability of the spacer.
Knee: how do you decide the size of the spacer?
The size is decided during the intervention, as we may count on the spacer trials and so we check which size fits best, additionally we perform test of stability of the ligaments.
How long does the spacer remain implanted? And during this period, how shall a patient behave?
We do perform the second stage after 3-4 months on average. This could be also done before, and this is true especially for the knee which is generally done after 2 months, while the hip may also require up to 4 months. During this period the patient may have a life of relationships quite normal, as the spacer guarantees a certain independence, as previously said, both to move around at home and for the personal hygiene. We anyway always advise to use crutches, and when necessary, also external braces, especially when we consider the knee
In general how long does it take to dismiss a patient?
Every patient is different, nonetheless we deem that after 2-3 weeks following the intervention the patient may be dismissed, when the sutures have been removed, when the wound is going well and we had the possibility to pass to oral antibiotic treatment. This is the routine practice, but of course there may be exceptions.
In relation to weight-bearing, how do you establish if the patient may give partial weight-bearing or if the patient may not give any load to the operated limb?
Weight-bearing is given as a function of the stability of the spacer evaluated during the intervention. If the prosthesis is stable, we behave as if it were a standard prosthesi, allowing partial weight-bearing: in consideration of the presence of infection we prolong a little the time of rest, but already after 48-72 hours the patient can start to give partial weight-bearing. Weight-bearing is instead delayed when the bone defect is wide or following very aggressive approaches. In these cases we just advise touch-down weight-bearing with the tip of the foot, thus trying to achieve a progressive load. As already said, all this is a function of the stability of the prosthesis verified during the intervention, the bone defect encountered or caused during the removal of the infected prosthesis.
Which are the risks for a patient walking without crutches?
Weight-bearing and walking capability are much more difficult, increasing the risk of a fall and therefore of fractures
In patients with large acetabular defects and/or proximal femoral defects, there is the risk of dislocation; the same happens when the extensor apparatus and/or the ligamentous apparatus of the knee are not good.
How can this problem be limited?
Using external braces, both at acetabular and knee level
Are there any cases in which the patient refuses the spacer removal? Which are in this case the risks for the patient?
In our experience we have only had two patients which have refused the spacer removal and the reimplantation of the final prosthesis. They were patients with a difficult post-op path, with several complications. In these two cases the patients had acute infections which required a re-intervention in two consecutive occasions, and once the infection problem got solved, they did not accept to undergo further surgery, as deemed too aggressive. These patients initially have not had any problem. We have followed-up them for 3 years, and so far they did not have any relevant complication.