Advertisements

Osteitis of the tibia

“Antibiotic and other antibacterial treatment are preferably delayed until it is biologically optimal to recruit antibiotics”,

 

A typical scenario is a limb broken within the last few weeks, which has been stabilised by an intermedullary nail, usually closely fitting. At times, the bone is reamed to make for an even closer fit. The patient presents with an ominous delay in healing of the surgical wound, a serous discharge, perhaps small spicules of dead bone, perhaps no bacteria cultured, or perhaps with a culture of one or more less aggressive bacteria.

 

One therapeutic approach is the “knee-jerk” reaction of immediately giving third or fourth generation antibiotics, perhaps culture appropriate, but often blindly.

 

The problem with this reflex response is that the space between the nail and bone is relatively non-vital – there cannot be a perfusion contribution from the side of the inert nail, and the tibial bone is particularly dense. The bone might also have been burnt by the reaming process, or rendered necrotic by injury to the vulnerable endosteal arterial supply. Compartment syndromes are a further threat to vitality of the underlying bone. This is because of damage to the peri-osteal arterial or venous structures.

Therefore it is highly unlikely that the antibiotic will have access to potentially infected areas. As a result the risk of biofilm on the inert implant and  non-vital, dense bone is high, These effects cause the antibiotic to be less than optimally effective, and there will be a significant risk of developing insensitive and resistant bacterial strains, risking causing these important “reserve” antibiotics to become resistant and ineffective.

 

An alternative and more appropriate approach is to leave the nail in situ if there any possibility of the fracture healing spontaneously and restrict usage of third and fourth generation antibiotics, keeping these prudently in reserve. We know that bone can heal in the presence of infection, and many examples of successful treatment occurred without any anti-biotic usage, notably before and during World War II.

Once some stability of bone is obtained, then

1.The nail is removed.

2.Antibiotic can now be delivered to the infected site in appropriate concentration, unhampered by the inert implant, ideally by:

3.A continuous lavage of the medullary cavity with antibiotic

4.In parallel with the antibiotic other forms of treating infection could be recruited, such as hyperbaric oxygen, or (for example) silver salts

5.Attention is given to nutrition to keep up protein levels and (particularly) iron supplementation, the serum concentrations of which always drop off in this condition.

6.Obvious and non-structural sequestrii can be removed.

 

Said another way, hold back on treatment until the infection can be hit with all available resources simultaneously. Piecemeal treatment by single treatment modalities, often randomly or reflexly chosen, given one at a time, will prove to be a pathway to failure. An established analogy is the de rigueur rule that an abscess should be drained before commencing antibiotics. [Most localised abscesses, once draining, do not need antibiotics to supplement healing, but this seems now to be forgotten since the reflex response to all “infections” is to administer antibiotics “routinely”]

 

Dead bone, still providing a structural function, can revitalise (even in the presence of infection), and the sensitive surgeon will wait to see how the biology responds. Important in this regard is the role of periosteum which, with its separate, more profuse blood supply, can provide a new bone as an “involucrum”, which provides a healthy, stable base for future reconstruction.   Early removal of large segments of (what are guessed to be) necrotic bone will lamentably also destroy this potentially vital periosteum.

There is no means of knowing how much bone is dead. This is because non-vital bone is difficult to identify at surgery, and therefore potentially vital bone is sacrificed by surgical aggression. If aggressive removal of large quantities of structural bone (as advocated by some) is performed surgically “boats are burned” and there is no going back.  

 

The “therapeutic trial” suggested above, where attention is paid to detail over an extended period, and where each therapeutic component is addresses as part of a holism, is innocuous, and “no boats are burned” and structural integrity of the tibia is protected.

Only when structural stability is obtained should focal necrotic bone be removed, perhaps preceded by a free vascularised bone graft. Vascularised fibula bone grafts grow well, as demonstrate when used to replace resections of the mandible and maxilla. These succeed in the highly infected environment of the mouth. This is further evidence that it is the non-vitality of dead bone which perpetuates osteitis, not the presence of pathogens. Using antibiotics does not revitalise a dead tibia! 

All persons should be given the option of vascularised transplant of bone prior to considering amputation.

 

Sadly, aggressive removal of the tibia can result in a leg without skeletal support, and which flops about disarmingly. The error of removing the tibial skeleton is often then multiplied by inserting a “traction-pin” into the calcaneum to counter the instability caused by excising the tibia. It is trite understanding that pins (which are commonly) inserted in the dense tibia, although usually infected where the skin is penetrated, do not cause a “spreading infective death” in the very resistant tibia.

The calcaneum is a very different structure, and its loose lattice-work of cancellous trabeculae allows infection to spread widely. It is dangerous to place pins into the calcaneum and in the presence of infection elsewhere in that leg, reprehensible, since an infected calcaneum is inevitable.

Curing an infected calcaneum is difficult or impossible, and often the infection of the calcaneum (at times iatrogenic) tips the balance into amputation. This is because even if the tibial infection is eventually cured, life with a chronically infected (and hence non functioning) calcaneum is intolerable 

   

It will be appreciated that with therapeutic demands which conflict in various degrees, at different times, finesse and skill are required in the management of tibial osteitis. It is here that the true “art” of medicine expresses itself, and where only the skilled and experienced succeed. The belief that there is a single “formula” or a “magical bullet” which will produce an instant cure is lamentably naive, and is the approach of the misguided amateur. Management is best if under the continuous supervision of a single, experienced, individual. This is not a field in which an orthopaedic surgeon, with a modicum of experience, can claim to be an “expert”.

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: