E-mail this article to a friend  Download this article in PDF format

Total knee arthroplasty: Pearls and pitfalls

By Paul A. Manner, MD

Common factors and specific recommendations in medical liability cases

Total knee arthroplasty (TKA) is one of the most successful and commonly performed surgical procedures in the United States; more than 400,000 TKAs are performed per year. Most TKAs proceed without incident or complication. As with any major surgical procedure, however, substantial risks—including infection, bleeding, venous thromboembolic disease, exacerbation of preexisting disease, and neurovascular disease—do exist.

Because so many TKAs are so successful, patients expect that their knee replacements will also be successful. Patients who experience complications, poor outcomes, and rare catastrophes often seek legal redress.

This article provides an analysis of medical liability cases surrounding TKAs found in legal databases, with attention to common factors. In addition, it summarizes several excellent articles on medicolegal aspects of knee arthroplasty and provides specific recommendations to reduce the risk of complications and improve documentation of patient care.

Database analysis
Two online legal databases, Lexis-Nexis and FastCase™, were used to evaluate legal actions that involved knee replacement surgery. These databases represent compendia of all legal proceedings in the United States. A representative sampling was performed; 20 cases (from a total database of 98 citations) were found in Lexis-Nexis and 100 cases (from a total database of 830 cases) were found in FastCase.

Most lawsuits involved infection, technical error, neurovascular injury, or early failure of knee implants. Less common reasons for the legal action included fracture following closed manipulation, postoperative injury and medical complications, and issues related to rehabilitation.

Approximately 30 percent of these actions resulted in payment to the plaintiff; the remainder were dismissed or overturned on appeal.

Article reviews
Ayers DC, Dennis DA, Johanson NA, Pellegrini VD: Instructional Course Lectures: The American Academy of Orthopaedic Surgeons. Common Complications of Total Knee Arthroplasty.
J Bone Joint Surg Am 1997;79:278-311.

This discussion of common TKA complications begins by addressing wound healing with a particular emphasis on vascular anatomy, incision site choice, and the need to avoid undermining the skin with extensive flaps. The authors stress the importance of not placing excessive tension on the skin during the procedure. The recent trend to perform TKA through smaller incisions underscores the importance of paying attention to skin integrity and avoiding undue tension. The surgeon should be ready to extend the incision proximally and distally as needed; the end of the incision should resemble a V rather than a U, which indicates high skin tension.

The authors also point out the importance of recognizing patient factors—such as corticosteroid use, diabetes, obesity, and nicotine use—that potentially prolong healing. They emphasize the need to manage wound complications aggressively and promptly.

Neurovascular injury, though rare, can have devastating sequelae. The surgeon must have a clear knowledge of where anatomic structures are located and take steps to protect them. The popliteal artery, for example, can be as little as 5 mm to 10 mm posterior to the tibia, even less if there is scarring due to previous injury or surgery. Performing the tibial cut in less than 90 degrees of flexion, as is commonly done in minimally invasive TKA, further reduces this distance. Early recognition of vascular injury and consultation with a vascular surgeon is crucial.

The peroneal nerve is at risk in patients with valgus and/or flexion deformity, which requires that the surgeon take specific care. In addition, patients must be warned of the possibility of injury to the nerve, as well as the sequelae of numbness, weakness, or a drop foot. As with vascular injury, the key to treatment is early recognition and aggressive management. This includes releasing all circumferential bandages, flexing the knee and hip, and using electromyography to establish a baseline for later evaluation.

Leone JM, Hanssen AD: Management of infection at the site of a total knee arthroplasty. J Bone Joint Surg Am 2005;87:2335-2348.

NIH Consensus Statement on Total Knee Replacement. NIH Consens State Sci Statements. 2003;20(1):1-34.

Namba RS, Dee DO, Paxton L, Fithian DC: Low-dose antibiotic loaded cement did not lower primary TKA infection rates. AAOS Proceedings, 2008.

Infection of a total knee replacement at a minimum can destroy the function of the joint; in severe cases, it threatens the limb and potentially the life of the patient. The National Institutes of Health (NIH) Consensus Statement on Total Knee Replacement notes that factors associated with wound and deep-tissue infection include a diagnosis of rheumatoid arthritis, diabetes mellitus, obesity, or glucocorticoid use. Patients with one or more of these conditions should be cautioned during all preoperative discussions of the possibility of superficial and deep infection.

Intraoperative factors—such as prolonged surgery, poor timing of antibiotic administration, and breach of sterile technique—may also increase the risk of infection. According to the NIH Consensus Statement, although “some data also support the use of antibiotic-impregnated bone cement (AIBC) as an additional means of reducing the deep-wound infection rate, concern regarding the availability, cost, and genesis of antibiotic-resistant strains of bacteria has tempered the enthusiasm for this strategy.” Namba’s study, for example, compared use of AIBC to bone cement without antibiotics in a prospective series of almost 16,000 TKAs and found that routine use of AIBC was unwarranted.

Data regarding the use of ultraclean-air operating rooms and whole-body exhaust-ventilated suits to reduce infection risk are conflicting and inconclusive. In any case, postoperative infection must be recognized and treated early and aggressively.

According to Leone and Hanssen, “although débridement with component retention may be successful in the acute postoperative stage of joint replacement, a two-staged revision with removal of all components followed by an adequate course of parenteral antibiotics prior to reimplantation remains the gold standard for eradicating chronic infection. The addition of antibiotic-impregnated cement spacers (static or articulating) has also been implicated as a useful adjunct to treatment. Long-term suppressive antibiotic treatment, arthrodesis, resection arthroplasty, and amputation are reserved for specific clinical situations in which a staged revision or débridement are unlikely to yield favorable results.”

Using c-reactive protein (CRP) and erythrocyte sedimentation rates (ESR) is invaluable in assessing the painful total joint. If levels of both ESR and CRP are elevated, the probability of infection is 83 percent; normal results for both indicate a 99 percent certainty of no sepsis.

Attarian DE, Vail TP: Medicolegal aspects of hip and knee arthroplasty. Clin Orthop Relat Res 2005;433:72-76.

This article describes the need for strict adherence to standard of care, full discussion with the patient regarding potential complications, and clear documentation. Standard of care encompasses the following four specific areas:

  • knowledge of the procedure
  • competence in performance
  • care in preoperative evaluation and diagnosis
  • diligence in patient treatment including informed consent, surgery, postoperative care, and complications

The importance of clear documentation for all four areas must be emphasized. In the current legal environment, the authors note that “…diligence in patient treatment requires the surgeons who do hip and knee arthroplasty to be thoughtful and aware of myriad issues and pitfalls. Informed consent must be obtained before surgery. Execution of the operative procedure and treatment of operative complications essentially must be flawless, aided by preoperative planning and templating of radiographs, checking the immediate availability of appropriate instrumentation and implants, and awareness of the entire operating room environment.”

Specific technical recommendations
As surgeons attempt to perform TKA through minimal-length incisions, they must be aware of the limits that smaller incisions place on exposing the surgical site. Although many patients can undergo minimal-incision TKA, surgeons should be prepared to extend incisions, evert the patella if necessary, and perform adequate soft-tissue dissection. Gentle handling of soft tissue is paramount for achieving healing.

Knowledge of anatomy, awareness of deformity, if present, and clear preoperative plans for addressing anatomic variants or deformity are fundamental. A standard implant may be inadequate for the patient who has a significant deformity or ligamentous incompetence; in these cases, ready availability of more constrained devices is crucial.

The surgical procedure should be performed expeditiously but not hastily; the entire team should be aware of the sequence of surgical steps. As the NIH Consensus Statement notes, “one of the most important factors leading to successful TKA is proper surgical technique; the rate of complications in some studies that utilized national administrative databases was inversely related to both surgeons’ and hospitals’ volume

of operations per year.”

Informed consent recommendations
The American Medical Association (AMA) provides the following guidelines for informed consent, pointing out that “Informed consent is more than simply getting a patient to sign a written consent form. It is a process of communication between a patient and physician that results in the patient’s authorization or agreement to undergo a specific medical intervention.”

The process requires the disclosure and discussion of the following topics:

  • diagnosis
  • nature and purpose of a proposed treatment or procedure, with risks and benefits
  • alternatives, regardless of cost or coverage by insurance, along with risks and benefits of these alternatives
  • risks and benefits of not being treated

The patient, in turn, should have the opportunity to ask questions to elicit a better understanding of the treatment or procedure, so that he or she can make an informed decision to proceed or to refuse a particular course of medical intervention.

Lastly, as the AMA guidelines point out, “it is important that the communications process itself be documented. Good documentation can serve as evidence in a court of the law that the process indeed took place. A timely and thorough documentation in the patient’s chart by the physician providing the treatment and/or performing the procedure can be a strong piece of evidence that the physician engaged the patient in an appropriate discussion.

“A well-designed, signed informed consent form may also be useful, but an overly broad or highly detailed form actually can work against you. Forms that serve mainly to satisfy all legal requirements (stating for example that ‘all material risks have been explained to me’) may not preclude a patient from asserting that the actual disclosure did not include risks that the patient unfortunately discovered after treatment. At the other extreme, listing all of the risks may not be wise either. A comprehensive listing will be difficult for the patient to understand and any omission from the list will likely be presumed undisclosed.” A list of this type may best be accompanied by wording that the list is not inclusive; one example would be language such as “including, but not limited to” just before the list.

Paul A. Manner, MD, has served on the AAOS Medical Liability Committee and frequently written for AAOS Now on medical liability topics. He can be reached at pmanner@u.washington.edu

Additional Resources

  1. Attarian DE, Vail TP. Medicolegal Aspects of Hip and Knee Arthroplasty. Clin Orthop Relat Res 2005 Apr;(433):72-6
  2. Ayers DC, Dennis DA, Johanson NA, Pellegrini VD. AAOS Instructional Course Lectures: Common Complications of Total Knee Arthroplasty. J Bone Joint Surg Am 1997;79:278-311.
  3. Leone JM, Hanssen AD. Management of infection at the site of a total knee arthroplasty. J Bone Joint Surg Am 2005;87:2335-2348.
  4. Namba RS, Dee DO, Paxton L, Fithian DC. Low-dose antibiotic loaded cement did not lower primary TKA infection rates. AAOS Proceedings 2008.
  5. NIH Consensus Statement on total knee replacement. NIH Consens State Sci Statements. 2003 Dec 8-10;20(1):1-34.
  6. Office of the General Counsel, American Medical Association; http://www.ama-assn.org/ama/pub/category/4608.html; accessed March 31, 2008.
  7. Spangehl MJ, Masri BA, O’Connell JX, Duncan CP. Prospective analysis of preoperative and intraoperative investigations for the diagnosis of infection at the sites of two hundred and two revision total hip arthroplasties. J Bone Joint Surg Am 1999; 81-A:672-83.
  8. Upadhyay A, York S, Macauley W, et al. Medical Malpractice in Hip and Knee Arthroplasty J Arthroplasty. 2007 Sep;22(6 Suppl 2):2-7.

AAOS Now
June 2008 Issue
http://www.aaos.org/news/aaosnow/jun08/clinical11.asp