55 Salvage of Osteomyelitis of the Distal Radius after Internal Fixation of an Open Fracture
55.1 Patient History Leading to the Specific Problem
A 57-year-old man presented initially with an open fracture of the distal forearm (▶Fig. 55.1a, b). Initial treatment in an orthopaedic and traumatology-oriented department included external fixation with additional palmar locking plate fixation of the radius and k-wire osteosynthesis of the distal ulna in the interval of several days. At the second operation, cancellous bone from the anterosuperior iliac crest was used to fill the osseous defect (▶Fig. 55.1c, d). Wounds did not heal primarily; a puncture with smeary secretion persisted. The patient was sent to the department of septic surgery. In the revision surgery, 2 weeks after definitive osteosynthesis, a sequestrum was found in the distal radius. Dead bone and necrotic soft tissue on the palmar side were removed. The bony cavity was filled with artificial bone and with a vancomycin carrier. Smear tests revealed Staphylococcus epidermidis as the pathogenic germ. Soft-tissue defect was covered another 14 days later with a free lateral arm flap from the contralateral arm by the department of plastic, hand, and reconstructive surgery of the hospital (▶Fig. 55.2). Flap was hooked up to radial artery (end to side) and vein (end to end). Despite all efforts, the infection could not be controlled during the next 6 weeks. Recurrent abscesses were found at a deep level, whereas soft-tissue coverage was sufficient.
55.2 Anatomic Description of the Patient’s Current Status
In the presented case, an open fracture led to acute osteomyelitis with concomitant bone and soft-tissue loss because of accompanying necrosis. Acute and chronic soft-tissue infection is thrombogenic and does often compromise local perfusion by occlusion of small and mid-size vessels. Despite specific local and systemic antibiotic therapy and radical debridement, the infection could not be treated satisfactorily. In addition, bone was not sufficiently stabilized despite the retained implants and despite the use of autologous and artificial replacement materials. Remarkable is the fact that soft-tissue coverage was sufficient and bony infection could at least be contained for 6 weeks through free tissue transplantation with the related advanced local perfusion. After the next revision surgery with excision of all necrotic bone and removal of all implants, it was necessary to address the challenge of a large bone defect with instability of the forearm (▶Fig. 55.3).
55.3 Recommended Solution to the Problem
Hardware in an infected site is coated by a biofilm within a short time. A biofilm consists of locally resistant bacterial colonies that are organized into coordinated functional communities through a slimy extracellular matrix composed of extracellular polymeric substances. The biofilm bacteria are able to share nutrients and are sheltered from harmful factors such as antibiotics and the immune system. Therefore, de novo radical debridement with removal of any hardware is strongly recommended. Temporary external fixation without the use of pins in direct trauma or infection zone should be considered. It should also be ensured that tissue is decontaminated from bacteria before definitive reconstruction of the bone may be achieved. In the literature, 6 weeks of local and/or systemic antibiotic therapy is typically recommended. One should realize that even after correct treatment there is still the risk of rest colonization with a single surviving bacteria.
Fig. 55.1 (a–d) X-ray images of the initial (open) fracture with related initial operative treatment.
Fig. 55.2 (a–c) Situation after removal of a sequestrum with corresponding soft-tissue defect after debridement, tenolysis, and anterior neurolysis. Defect coverage was performed by a free lateral arm flap. Note retained hardware.
The resulting bone defect is challenging. This holds especially true in a site with limited perfusion and contamination. The aim of the reconstruction was to preserve the distal part of the bone with the nearly sustained radiocarpal joint surface to maintain a residual mobility. Therefore, in the presented case a vascularized fibular autograft was used. It was inserted into the medullary cavity of the distal radius in combination with cancellous bone. Initially, a common end-to-end osteosynthesis with a long and exceptionally stable locking plate was performed.
55.3.1 Recommended Solution to the Problem
• Radical debridement with hardware removal.
• Meanwhile, external fixation provides stability and bridges the injured part of the bone.
• Wait for the antibiotic effect after all necrotic substrate for bacteria has been removed.
• Reconstruct the distal radius including preservation of the radiocarpal joint surface in an interval of approximately 6 weeks.
• We recommend free microvascular bone grafts for the reconstruction of bone defects that exceed 4 cm in length.
• An intercalated vascularized fibular autograft in combination with cancellous bone graft from iliac crest was suitable in the presented case.
Operation is performed under general anesthesia with use of tourniquets in two bloodless fields, separate for the arm and the leg. The use of loupes is highly recommended.
The recipient site is debrided; the remaining bone is checked for vitality. Hemorrhage spots are required to be identified; if unsure, check again after opening the tourniquet. The defect size is measured. The recipient vessels are exposed. Usually, the radial artery with its concomitant veins is used. In this case, because of the preceding flap, ulnar vessels were used. The angiography (conventional digital subtraction angiography) revealed two uninterrupted vessel axes beforehand.
The patient is placed in the supine position with the ipsilateral hip slightly elevated. The axis of the fibula is drawn. The axis of the skin paddle follows the posterior border of the fibula and incorporates a septal perforator near the midpoint of the fibula. The cutaneous flap is elevated just above the muscle and deep to the muscular fascia from anterior to posterior. A small cuff of muscle is left attached to the bone. Osteotomy is made with an oscillating saw. It is important to preserve the distal 6 to 7 cm of the bone to ensure the integrity of the upper ankle joint. The interosseous membrane is divided exposing the peroneal vessels just behind the membrane. The flap can then be raised with its vascular pedicle (▶Fig. 55.4).