Sepsis and Total Knee Arthroplasty

Perioperative Prophylactic Measures

It is obviously preferable to prevent an infection rather than have to treat one. Prophylactic measures can be taken before, during, and after surgery to minimize the chance for infection.

All patients should be screened preoperatively for potential sites of active infection that could spread to the knee. The most common are oropharyngeal and urologic. Any patient with a chronic infection such as sinusitis or pharyngitis should be cleared by an otolaryngologist before surgery. Similarly, patients with chronic dental infection in need of reconstructive procedures should have these performed before the arthroplasty.

It is not unusual to encounter a female patient with a history of recurrent urinary tract infection. Many advocate that a urinalysis and urine culture should be obtained preoperatively on all patients.

Any active urinary tract infection should be treated, and chronic problems should be cleared by a urologist. If a preoperative urine culture is positive, but few white cells are present in the sediment and the patient is totally asymptomatic, the surgery need not be canceled. A repeat clean-catch or catheterized specimen can be helpful to clarify whether antibiotic treatment of the infection is necessary.

Preoperative Germicidal Skin Scrub

All my patients were instructed to use a chlorhexidine germicidal skin scrub (e.g., Hibiclens) twice daily for 2 days before their surgery. In theory, this should decrease the colonization of bacteria on the patient’s skin and the chance for contamination.

Surgical Preparation and Draping

It was my practice to prepare the entire extremity, including the foot, for TKA. The foot was draped out of the surgical field, of course, but I am more comfortable with this area being surgically prepared in the event of any breakdown in the drapes that cover the foot. I used a surgical stockinette over the prepared foot up to the level of the tourniquet. The stockinette had a double layer. The outer layer was cut, and the incision was defined with a marking pen. The inner stockinette was then cut and reflected medially and laterally for a few centimeters. The skin incision was drawn out, and then the entire field was sealed with a povidone-iodine–impregnated adhesive drape. Care was taken to not actually touch the skin during this draping procedure, and fresh outer gloves were applied after it was completed (see Chapter 2 ).

Laminar Air Flow Versus Ultraviolet Lights

I was often asked by ex-fellows or residents whether laminar airflow or ultraviolet (UV) light is better. Each method has advantages and has been shown to be an effective deterrent to infection. The UV light method is less expensive and requires all operating room personnel to cover up to shield their eyes and skin, which may decrease the potential for the shedding of bacteria by personnel. The fact that UV lights are potentially “sterilizing” the field during the procedure is reassuring when performing sequential bilateral TKAs. In the absence of UV lights, I sequestered the instruments that were used on the first knee during the skin closure and passed them off the operating field after they had been used. A change of outer gloves was also performed between the procedures (see Chapter 11 ).

Intravenous Antibiotics

Intravenous (IV) antibiotics have long been shown to decrease the incidence of perioperative orthopedic wound infection. I commonly used a second-generation cephalosporin, giving 1 g IV at least 10 minutes before inflation of the tourniquet. A second 1 g was administered at the time the tourniquet was deflated to maximize the concentration of antibiotic in the evolving wound hematoma. The antibiotics were continued every 8 hours for three additional doses. In patients allergic to penicillin, I still administered the cephalosporin, unless the allergy had been one of anaphylaxis. A test dose was given with caution and under surveillance by the anesthesiologist. If the test dose was well tolerated, the standard protocol was used. Although there is said to be a crossover in sensitivity between penicillin and cephalosporins of as much as 15% in terms of allergy, in hundreds of cases over two decades of using this protocol, I never saw this crossover. Passing this test dose also clears a penicillin-sensitive patient to receive a cephalosporin in the future, should that be appropriate.

Proper Skin Incision

Prior skin incisions around the knee must be respected. The knee does not tolerate multiple parallel incisions, especially a medial incision made parallel to an old lateral incision (see Chapter 13 ). If skin breakdown were to occur, infection is more likely. My standard incision was approximately 15 cm long. It begins 5 cm above the patella centered over the shaft of the femur, crosses the medial third of the patella, and ends distally at the medial aspect of the tibial tubercle. In general, when prior incisions are present, it is best to use the most lateral incision that allows arthroplasty or the most recent incision that healed without difficulty (see Chapter 13 ). Medially based flaps are safer than laterally based flaps. In questionable cases, the skin incision can be made with the tourniquet deflated. If the wound edges appear poorly vascularized, the surgery can be aborted and plastic surgical consultation obtained. I have used tissue expanders successfully on several occasions in the presence of extremely thin or adherent skin after trauma, a skin graft, or an old healed sinus tract.

Wound Care

After the skin incision and arthrotomy, I always sewed in wound towels along the capsule that protect the subcutaneous tissue from debris and from drying out under the operating room lights. The towels were irrigated with saline solution. When they were removed at the end of the procedure, it was always impressive to see how healthy the tissues appeared compared with the brown, dried-out appearance of the subcutaneous tissues when wound towels have not been used ( Fig. 12.1 ).

Infection is often a result of wound necrosis secondary to compromise of blood supply to the skin and subcutaneous tissue. For this reason, in a lateral retinacular release, it is beneficial, if possible, to preserve the lateral superior genicular artery ( Fig. 12.2 ). Infection also can be the result of breakdown of the wound caused by a large hematoma. To minimize this possibility, I always deflated the tourniquet before wound closure to check for significant bleeding points.

During rehabilitation, if the capsular closure loses its integrity, a wound problem can occur. For this reason, I preferred an interrupted capsular closure with a strong monofilament suture. My preference was No. 1 polydioxanone (PDS).

The use of suction drains after TKA is controversial. Fewer surgeons are using drains than in prior years, but they should still be considered in selected cases. The studies that support the contention that they are unnecessary involve only several hundred cases. In my opinion, a review of a thousand consecutive cases without the use of a drain would likely reveal at least one significant complication such as wound breakdown, necrosis, secondary infection, or even compartment syndrome that would cost the patient and society more than the price of a thousand standard suction drains. These drains do their most important work during the first several hours after surgery. I always discontinued their use on the morning after surgery. If for some reason the drain output was excessive, I flexed the knee for 30 minutes and clamped the drains. If excessive output continued, I considered removing the drains. The wound can then be observed carefully over the next 24 hours, and, if necessary, the patient can be brought back to the operating room to control any bleeding. In my experience, this was rarely necessary.

The skin closure is one of the most important parts of TKA. It must be meticulously performed with the skin edges accurately opposed. I preferred the modified Donati suture ( Fig. 12.3 ), which is a vertical mattress suture that is subcuticular on the lateral side (the side more prone to skin necrosis). I preferred an interrupted closure over a running subcuticular stitch because the length of a knee incision increases as much as 40% from extension to flexion. This movement puts a repetitive strain on the subcuticular suture. An interrupted closure allows the removal of a few localized stitches to deal with a superficial wound separation or infection. Many surgeons, however, use a subcuticular closure augmented by surgical glue. They also often leave wounds covered with an impervious antiseptic dressing for up to 10 days. I personally preferred my patients to undergo an initial dressing on the second postoperative day to check for wound integrity and drainage, however minor. I believe that any perioperative wound problems should be dealt with aggressively to prevent the chance for secondary infection (see Chapter 13 ). If wound drainage persists after 48 hours, my preference was to perform a sterile preparation on the area and apply benzoin and Steri-Strips to reseal the wound. If the problem failed to resolve, I would take the patient back to the operating room for treatment using the following protocol: The knee joint is separately aspirated for cell count and culture. Antibiotics (hopefully prophylactic rather than therapeutic) are initiated after the culture has been obtained. The few sutures in the local area are removed, the wound is irrigated, and minor débridement is performed. The wound is then reclosed with interrupted vertical mattress sutures. Prophylactic antibiotics are continued for several days until the wound appears totally sealed and benign. If the joint aspiration is positive with a high cell count or positive culture, major débridement and lavage of the knee joint are obviously necessary.