JAAOS review addresses persistent drainage, modifiable patient risk factors
Wound complications after total knee arthroplasty (TKA) are rare—with only 0.33 percent of more than 17,000 patients in a Mayo Clinic registry requiring surgical intervention within 30 days. However, when complications do occur, they can be serious and expensive. Acute complications range from quickly resolved drainage and small superficial eschars to serious conditions such as persistent drainage and full-thickness tissue necrosis that may require advanced soft-tissue coverage.
An article in the August issue of the Journal of the American Academy of Orthopaedic Surgery reviews the issues and considerations related to acute wound complications following TKA and covers strategies for preventing problems in healing and managing problems that arise.
Persistent drainage is an important sign that a surgical wound may become problematic, the authors write. Postoperative incisional drainage occurs in 1 to 10 percent of patients undergoing primary TKA, but after the skin heals, drainage should diminish or cease. Drainage that continues beyond 1 week, whether light, persistent drainage or massive acute effluence, is particularly concerning and typically requires surgical intervention.
"It is critical to recognize modifiable and nonmodifiable risk factors, as well as technique variables that may obstruct proper wound healing," the authors write. "To prevent complications and lessen the potential for infection, surgeons must address patient preoperative medical optimization, use meticulous surgical technique, and recognize a problem wound early to implement proper and expeditious wound management."
The article discusses preoperative medical optimization, outlining approaches and measures for patients with medical conditions and issues, including diabetes, obesity, smoking, rheumatoid arthritis (and associated medications), anemia, and nutritional deficiency.
Preoperatively, the authors explain, surgical consultation with an expert in flap coverage and microvascular techniques for soft-tissue management should be considered if difficulties with closure or wound healing are anticipated. Before the surgery, the area about the knee should be meticulously evaluated for evidence of prior incisions because more medial incisions interrupt the blood supply closer to the source, potentially compromising wound healing along the lateral skin edge. "The most lateral, vertical incision" is safer, the authors write. The skin incision should be long enough to prevent excess tension on the wound edges (Fig 1).
J Am Acad Orthop Surg
Meticulous hemostasis "is imperative to prevent postoperative hematoma and persistent drainage," the authors write. "Any vessels exposed during the dissection should be cauterized because a wound hematoma is frequently the initiating event to wound breakdown." They also note that minimizing the infrapatellar fat pad resection lessens the chance of hematoma formation and potential drainage.
After surgery, drainage affects 1 to 10 percent of patients. Persistent incisional drainage after TKA—defined as continued (>72 hours) and substantial (>2 × 2 cm area of gauze)—is abnormal. Most cases spontaneously resolve, but profuse and persistent drainage (for >5 to 7 days) is unlikely to stop, and surgical intervention is typically required, the authors write. In the article, the authors provide a treatment algorithm for acute incisional knee drainage (Fig. 2).
J Am Acad Orthop Surg
In an interview with AAOS Now, two of the article's authors, Matthew J. Simons, MD, and Giles R. Scuderi, MD (the third author is Nirav H. Amin, MD), elaborated on prevention and optimization strategies and on management of complications that do arise.
AAOS Now: What prompted you to focus on the knee?
Dr. Simons: While the incidence of wound complications following TKA may be low, the soft tissue around the knee, however, tolerates far less compromise before progressing to a complicated wound problem. An early wound problem can easily develop into a chronic condition, including periprosthetic infection.
AAOS Now: What should surgeons do to practice proper vigilance and to monitor draining to differentiate among normal but slow-healing noninfected wounds, superficial infections, and deep infections?
Dr. Simons: To prevent complications and lessen the potential for infection, surgeons must address patient preoperative medical comorbidities and use meticulous surgical technique, especially in the presence of prior incisions and stiffness. They also must recognize a problem wound early to implement proper and expeditious wound management.
AAOS Now: What can surgeons do to lessen the incidence and negative effects of TKA infections?
Dr. Simons: Complex primary TKA and revision TKA are complex procedures that require extensile exposure with greater soft-tissue dissection. Despite performing a successful arthroplasty, delayed wound healing and persistent drainage can easily lead to a periprosthetic infection. It is critical to recognize modifiable/nonmodifiable risk factors such as prior surgery with prior incisions, limited motion, and retained hardware that may need to be removed, as well as technique variables that may interfere with proper wound healing.
AAOS Now: In patients who smoke, what are the practical challenges counseling patients and actually getting them to cease smoking?
Dr. Scuderi: Smoking is another example of a modifiable risk factor associated with increased short-term complications after TKA, as nicotine and the byproducts of smoking cause vasoconstriction. Smokers have approximately twice the rate of deep infection compared to former smokers or nonsmokers. They also have increased rates of superficial wound infection and wound dehiscence compared to nonsmokers.
Counseling and nicotine-replacement 6 to 8 weeks prior to total knee or hip arthroplasty compared with no intervention demonstrated a significantly decreased overall complication rate in the smoking cessation group.
AAOS Now: And what do you advise for obesity and diabetes?
Dr. Scuderi: The risk of postoperative complications after TKA is higher in obese patients, especially those who are morbidly obese. Counseling obese patients about weight loss, including bariatric surgery, prior to knee replacement is advisable; however, it should be emphasized that complication rates are high, whether one has bariatric surgery prior to or after knee replacement. The metabolic changes to the skin in obese patients after bariatric surgery include poorly organized collagen, elastin degradation, and scar formation intermixed within normal tissue.
Dr. Simons: While limited research has been performed on precise perioperative blood glucose values to prevent wound complications, early preoperative medical assessment should be arranged to develop a perioperative diabetes management strategy and to identify and optimize other comorbidities.
AAOS Now: Regarding soft-tissue considerations, what is your practical advice for getting microvascular consultation?
Dr. Simons: Preoperative plastic surgery consultation for soft-tissue management should be considered if difficulties with closure or wound healing are anticipated, especially in patients with previous incisions, severe varus or rotational deformity, and prior trauma with contracted and immobile skin. Prior soft-tissue flaps about the knee should also prompt evaluation by a plastic surgeon to gain detail on the tissue quality and the vascular pedicle. A vascular surgeon may also be consulted should there be concern for general circulatory compromise, as poor venous return may lead to wound edge ischemia and necrosis from venous engorgement.
AAOS Now: Regarding other technique considerations, what reminders and tips might benefit surgeons and lead to better outcomes?
Dr. Scuderi: The presence of prior incisions should be carefully evaluated. When multiple scars are present, it is thus safer to use the most lateral vertical incision. Transverse incisions should be crossed at 90 degrees. Short oblique incisions may be incorporated into a new vertical incision provided it is near the midline. Ideal spacing between multiple vertical incisions includes a 7-cm skin bridge, as close, parallel incisions may compromise the epidermal blood supply. The skin incision should be of adequate length to prevent excessive tension on the wound edges.
Using full-thickness skin flaps to avoid undermining the skin and avoiding a lateral retinacular release will help preserve lateral skin oxygenation and reduce the risk of skin necrosis. Meticulous hemostasis can prevent hematoma and persistent drainage. A tension-free closure with correct wound-edge alignment is paramount to prevent skin necrosis and potential drainage.
AAOS Now: And in postoperative management?
Dr. Scuderi: Serosanguineous drainage is not uncommon within the first 24 hours, but drainage beyond 72 hours is concerning and warrants intervention. Patients with a draining wound on postoperative days 2 to 3 should remain in the hospital for close clinical monitoring and may initially be treated with compressive dry dressings. Physiotherapy, especially range-of-motion exercises, may need to be postponed and the knee put to rest until the drainage ceases.
Incisions that drain serous fluid after the second postoperative day are indicated for negative pressure wound therapy. A persistently draining wound for greater than 5 to 7 days should be reoperated on expeditiously to prevent a deep periprosthetic joint infection.
AAOS Now: Please elaborate on the statement from the article that "early prophylactic irrigation and débridement is preferable to delayed management or no management to mitigate or prevent the potentially devastating postoperative problems of wound breakdown leading to an established infection."
Dr. Simons: Patients who underwent débridement at a mean of 5 days following the onset of drainage are more likely to be infection free at 1 year compared to patients who underwent delayed débridement at a mean of 10 days. Since drainage beyond 5 to 7 days is unlikely to stop, surgical intervention is now advocated.
The authors note that even when appropriate measures to reduce complications are taken, soft-tissue problems may still occur. "When an acute wound problem occurs," they write, "the guiding principle is close monitoring and aggressive prophylactic intervention to resolve the complication before a secondary periprosthetic infection occurs."
The authors also point out that "the optimal definitive surgical treatment continues to be refined." Ongoing discoveries of new markers to diagnose early deep infection may help in distinguishing between primary aseptic healing problems and secondary complications from a deep infection.
The article "Acute Wound Complications After Total Knee Arthroplasty: Prevention and Management" appears in J Am Acad Orthop Surg 2017;25:547-555.
Terry Stanton is the senior science writer for AAOS Now. He can be reached at firstname.lastname@example.org.