and Septic Arthritis in Adults

Anatomic type

Description

Initial surgical debridement and dead space management

Reconstruction

I: Medullary

Biofilm nidus in endosteum (scar, implant, dead bone)

Unroofing by corticotomy, canal reaming, or both

Dead space in medullary canal managed by bone grafting

± antibiotic depot (PMMA)

± primary closure

Protect if fracture risk (cast or ex fix)

II: Superficial

Nidus is an exposed bony surface, no medullary involvement

Soft tissue loss is main concern

Local transposition flap

Superficial bony debridement

III: Localized

Full thickness, cortical sequestrum, medullary involvement, soft tissue defect possible

Combination of types I and II

Local transposition flap dead space in medullary canal managed by bone grafting

Bony and soft tissue defects

Protect if fracture risk (cast or ex fix)

± Antibiotic depot (PMMA)

IV: Diffuse

Permeative bony destruction which is often circumferential, unstable

Most difficult, treatment is always staged

Strategies used alone or

in combination include

Extensive debridement causes bony instability or segmental defect

(1) Acute shortening

(2) Bone transport

± Antibiotic depot(PMMA)

(3) Bypass procedures

Protect if fracture risk (cast or ex fix)

(4) Osteotomy with or without lengthening

Source: Cierny [2]

Decision-making is facilitated by knowledge of the patient’s clinical condition, expertise of the clinician, local facilities, economics, and sociocultural factors. A visiting surgeon should be cautious and sensitive to all these issues and ask for input from local caregivers. The visitor must also be sure that the treatment can be completed in his or her absence. There may be times when dependent drainage is the best treatment. The primary goal is to improve the patient’s quality of life, and on occasion the risks of limb salvage may outweigh the benefits. If ablative surgery is considered, the surgeon must take stock of local availability and affordability of prosthetics prior to embarking on a shared decision-making approach with the patient and local staff.

While debridement of all infected tissues is necessary, dead space management and reconstructive needs vary. Some of the tools are resource intensive and impractical; however, the general principles are crucial and can be adapted for use when resources are limited. The place of incision for dependent drainage is the most important factor. While sinograms can be considered, we prefer to pass a probe or curette intraoperatively to define the sinus track. The biological environment must be respected by careful tissue handling and avoiding subperiosteal stripping and placement of circumferential retractors.

Both sequestra and involucra are harder to define in adults than in children. It is generally easier to perform the debridement with a tourniquet inflated and through an oval cortical window (Fig. 32.1). The tourniquet can be deflated to assess the adequacy of debridement. Exposed viable cortex bleeds in a uniform Haversian pattern, and cancellous bone bleeds in a sinusoidal pattern, termed the “paprika sign.”

../images/270913_2_En_32_Chapter/270913_2_En_32_Fig1_HTML.jpg — Fig. 32.1

(a) This case of tibial osteomyelitis with two thin sequestrae visible along the anterior open area of the cortex of the proximal tibia was (b) treated by sequestrectomy and debridement. Further management might include open cancellous bone grafting or gastrocnemius flap. (Courtesy of Dr. Sam Baker)

Dead space management may include polymethyl methacrylate spacers that provide local antibiotic delivery in high concentration and temporary structural support prior to definitive bony reconstruction. The role of intravenous or oral antibiotics is not well defined, and we recommend that they be considered as an adjunct to aggressive surgical care. A 24-h perioperative course will suffice for most patients, especially when access to antibiotics is limited. The need for long-term antibiotic therapy must be assessed on a case-by-case basis. Management of retained implants must be considered and depends on the degree of healing when the infection is diagnosed. In early infections, it may be best to perform an initial irrigation and debridement while retaining the implants if they are secure, followed by their removal once union has occurred. It is easier to treat an infected union than an infected nonunion.

Once the local environment has been sterilized by debridement and the sepsis controlled, options for reconstruction of localized or segmental defects include (1) acute shortening, (2) cancellous bone graft, (3) structural free autograft, (4) structural allograft, (5) vascularized autograft, (6) bone transport, and (7) bypass procedures (forearm or lower leg).

Acute shortening up to 2 cm in the lower limb is generally well tolerated and can be offset by a shoe lift. A bigger challenge is how to stabilize and compress the site. External fixators may provide sufficient stability to promote union but are often difficult for patients to manage. Internal fixation may provide greater stability for bone healing; however, there is an increased risk of local wound sepsis. Internal fixation can successfully treat septic nonunions if the biological and mechanical environments are optimized, for example, with an intramedullary implant. Internal fixation from both inside (intramedullary device) and outside (plate) will cause cortical necrosis, and this “dead bone sandwich” has a very high risk of becoming infected. Cerclage wiring almost guarantees necrosis of the segment and should be avoided at all costs.

Cancellous grafting is useful for localized bone defects. Structural free grafts, such as the fibula, which are useful in children are a concern in adults since avascular bone is inserted into tissues which were previously infected. In addition, donor site morbidity should also be considered. Vascularized autografts are usually beyond the capabilities of austere environments.

Bone transport using a monolateral or ring fixator is an option for defects greater than 2 cm in facilities with adequate equipment, expertise, and rehabilitation services and in patients who can sacrifice the time and money involved (Fig. 32.2).

../images/270913_2_En_32_Chapter/270913_2_En_32_Fig2_HTML.png — Fig. 32.2

(a) A 17-year-old male presented 6 months after sustaining an isolated closed fracture of his left femoral shaft in a road traffic crash that was treated surgically with two retrograde flexible nails and a cerclage wire. Cerclage wiring almost guarantees necrosis of the segment and should be avoided. He developed wound sepsis. The flexible nails had backed out and been hammered back up, transgressing the hip joint. At presentation he had purulent drainage, scarred soft tissues, and stiffness of both the hip and knee. (b) He was treated by debridement of 6 cm of devitalized bone and removal of implants. The bone defect was filled with gentamicin beads, and a monolateral external fixator was applied. The beads were removed after 2 weeks, and a third set of pins were inserted distally to facilitate corticotomy and bone transport

Soft tissue coverage can often be achieved with local fasciocutaneous or other flaps when primary or delayed primary closure is not an option (see Chap. 14). Vacuum-assisted wound closure or negative-pressure wound therapy is useful and can be made simply and economically (see Appendix 4).

It is vital to think of rehabilitation and restoration of function from the outset of treatment, as muscle atrophy is common and ongoing sepsis exacerbates joint stiffness. An aggressive approach to infection control and stability management is required for rehabilitation (Fig. 32.3).