Lawsuits After Primary and Revision Total Knee Arthroplasty

A Malpractice Claims Analysis

Diana C. Patterson, MD; Ronald Grelsamer, MD; Michael J. Bronson, MD; Calin S. Moucha, MD

J Am Acad Orthop Surg. 2017;25(10):e235-e242. 


Abstract and Introduction


Introduction: As the number of total knee arthroplasties (TKAs) increases, the number of associated complications will also increase. Our goal with this study was to identify common causes of and financial trends relating to malpractice claims filed after TKA.

Methods: We analyzed malpractice claims filed for alleged neglectful primary and revision TKA surgeries performed between 1982 and 2012 by orthopaedic surgeons insured by a large New York state malpractice carrier.

Results: We identified 69 primary and 8 revision TKAs in the malpractice carrier’s database. All cases were performed between 1982 and 2012; all claims were closed between 1989–2015. The most frequent factor leading to lawsuits for primary TKA was chronic pain or dissatisfaction in 12 cases, followed by nerve palsy in 8, postoperative in-hospital falls in 5, and deep vein thrombosis or pulmonary embolism in 3. Medical complications included acute respiratory distress syndrome, cardiac arrest, and decubitus ulcers. Contracture was most common after revision TKA (three of eight cases). Mean indemnity was $325,369, and the largest single settlement was $2.42 million. The average expense relating to the defense of these cases was $66,365.

Conclusions: Orthopaedic surgeons should continue to focus attention on prevention of complications and on preoperative patient education. Preoperative counseling regarding the risks of incomplete pain relief could reduce substantially the number of suits relating to primary TKAs.


Total knee arthroplasty (TKA) is one of the surgical procedures most frequently performed by orthopaedic surgeons. Compared with other surgical interventions, knee replacement surgery provides substantial health gains in quality of life and in cost-effectiveness,[1–3] although it is not without known morbidity or complications. More than 600,000 TKAs were performed in 2009 in the United States, and this number continues to increase every year.[4] Large population-based studies repeatedly have shown TKA to be extremely cost effective.[3–5]

Nevertheless, with the increase in the number of primary TKAs, the number of complications and failed surgeries, reports of patient dissatisfaction, and need for revision will increase, as well. Any complication may lead to patient discontent and, as a result, spur malpractice allegations.

In general, orthopaedic surgery is a specialty prone to a high risk of malpractice allegations. One study analyzing the cases of one large professional liability insurer between 1991 and 2005 found that the proportion of orthopaedic surgeons facing a claim was approximately 15% per year, with a little less than one third of suits leading to payouts.[6] The mean payment was $233,072. However, in each year of this study, 7.4% of physicians overall had a malpractice claim, and just 1.6% had a claim leading to payment. Within the English National Health System Litigation Authority (NHSLA), more than $321,695,072 was paid in settlements related to adult orthopaedic surgery for nearly 5 million orthopaedic surgical procedures performed between 2000 and 2006; damages secondary to litigation after TKA totaled $13,509,480.[7] In a study of claims in the NHLSA arising between 1995 and 2001, consisting of 2,117 orthopaedic surgery cases across many subspecialties, Kahn et al[8] found that the most common causes of claims were postoperative complications, incorrect diagnosis, inadequate consent, and surgery performed at the incorrect site. We hypothesized that these findings would be similar to those in the TKA subcategory in New York state.

The goal of this study was to identify the most common reasons for malpractice suits filed after primary and revision TKA. Additional goals were to investigate the costs of claims, indemnities rewarded, and overall trends and associations.


All closed malpractice claims involving primary and revision TKA performed between 1982 and 2012 were provided by the Federation of Jewish Philanthropies (FOJP) Service Corporation, an underwriter of medical professional liability insurance for a large number of hospitals and health systems across New York. All claims alleged improper TKA surgery and/or negligent postoperative care. All claims were closed between 1989–2015. An orthopaedic surgeon specializing in TKA (C.S.M.) and one orthopaedic resident (D.C.P.) collected and reviewed all medical and surgical diagnoses in the claims data. They reviewed all pertinent data the malpractice carrier provided, including data on intraoperative occurrences, in-hospital falls or medical complications, and postoperative complications. Physician and patient confidentiality was maintained according to the standard policies of the FOJP. Because these human subject data were preexisting and unidentifiable, no institutional review board approval was required.

We identified cases from the FOJP by using the International Classification of Diseases, Ninth Revision, Clinical Modification codes listed in Table 1. Demographic information for patients included age, sex, date of loss, date of opening and closing of claim, indemnity paid, expenses paid, procedural codes, admitting diagnosis, other relevant diagnoses, and detailed allegations. We grouped adverse outcomes into immediate postoperative or more distantly postoperative complications and as either intraoperative or in-hospital versus after discharge. We then further subdivided outcomes into orthopaedic or general medical concerns. Intraoperative and short-term orthopaedic complications included nerve injury, vascular injury, wound complications, leg-length discrepancy, and in-hospital falls. Orthopaedic complications occurring after or noted after discharge from the hospital included infection, malrotation, instability, loosening, contracture, chronic pain, and miscellaneous patient dissatisfaction. Medical complications included deep vein thrombosis and/or pulmonary embolism, cardiac arrest, cerebrovascular accident, medication overdose, gastrointestinal and urologic complaints, decubitus ulcers, dental injury, and death.

All cases made available for analysis were closed. The legal expenses of the suit and the indemnities paid to the plaintiff were normalized to 2015 dollars on the basis of the Consumer Price Index.[9]

DeNoble et al[10] described the method used to estimate the annual incidence of TKA malpractice claims among orthopaedic surgeons covered by the FOJP. We quantified the incidence of TKAs in New York state by using de-identified discharge data from the New York Statewide Planning and Research Cooperative System database for 2014.[11] This database included all discharge data from inpatient stays in nonfederal hospitals in New York state by year, with the most recent data available from 2014. We extracted the population of orthopaedic surgeons in New York state from the 2014 American Academy of Orthopaedic Surgeons census,[12] and the FOJP provided the number of orthopaedic surgeons they insured. We then calculated the annual incidence of TKA lawsuits on the basis of these numbers and study data from 2008 through 2012.

The FOJP distributed all de-identified data and details of claims as Excel spreadsheets (Microsoft). We reviewed all cases and defined and tabulated the primary cause of each malpractice claim. We performed univariate analysis by using Excel spreadsheets to extract the descriptive statistics (ie, mean, range) of age, overall cost, cause-specific cost, and time from surgery to closure of the case. For cost and indemnity analysis, we adjusted the variables denominated in dollars to 2015 dollars by using the all-urban Consumer Price Index.[9]


We identified 77 malpractice cases in the carrier’s database: 68 after primary TKA and 9 after revision TKA. One of the primary cases contained two clinically significant allegations, and two of the revision cases similarly alleged two separate etiologies of malpractice. The American Academy of Orthopaedic Surgeons 2014 census stated that there were 1,647 orthopaedic surgeons in New York state. The FOJP stated that it insured 70 orthopaedic surgeons—4.2% of orthopaedic surgeons in the state. The New York Statewide Planning and Research Cooperative System database indicated that 33,030 TKAs were performed in New York state in 2014, approximately 1,127 of which were performed by physicians insured by the FOJP. Between 2008 and 2012, there were 18 claims relating to TKA filed against physicians insured by the FOJP, or 0.27% annual incidence of malpractice claims per year in our dataset. Of the 77 claimants, 46 were women and 31, men. The mean age at the time of surgery was 64.1 years (range, 32 to 86 years). The mean time from surgery to case closure was 6.39 years (range, 0.5 to 14.58 years). In the group of patients in our study, 34 claims were opened for cases performed between 1982 and 1998 and 43 for cases between 1999 and 2012.

Chronic pain (12 claims) and allegations of negligence or improper performance of surgery were the allegations cited most frequently after TKA. Nerve palsy (footdrop) occurred in eight cases; wound complications occurred in three cases, two of which required muscular flap coverage; infection occurred in five cases, one leading to death; contracture occurred in four cases. Vascular injury occurred in three cases; only one case of vascular injury resulted in amputation, but that case consisted of bilateral TKAs that resulted in bilateral vascular injuries and amputations—one above-knee and one below-knee amputation. Deep vein thrombosis or pulmonary embolism occurred in three cases, with two resulting deaths. One patient died of cardiac arrest and one of a postoperative drug overdose. One patient had an epidural hematoma leading to paralysis after receiving spinal anesthesia, and a separate patient suffered severe brain injury following epidural anesthesia with air visualized on brain imaging. Implant failure was cited in two cases (one being an unspecified liner failure and the other a tibial post fracture); component malrotation in one case; and instability in four cases. There were five cases of in-hospital falls caused by alleged improper supervision. Two of these falls resulted in injuries that required further orthopaedic surgery, including bilateral wrist fractures, a hip fracture, and a wound dehiscence.

Medical complications were the primary cause in 14 cases, including two complications in one case. A patient with acute respiratory distress syndrome requiring prolonged and repeated intubations reported dental injuries. There were three deaths. One case of superior mesenteric artery syndrome required emergency bowel resection. Two cases involved alleged sexual assault by a male aide on a female patient. Other medical complications are described in Table 2.

In revision cases, contracture or dissatisfaction was the most common complication, occurring in three cases. Nerve injury occurred after two revisions. Loosening, wound dehiscence, and unexplained pain occurred in one case each. The wound dehiscence case required a vascular bypass and provision of a muscular flap by means of plastic surgery.

Thirty-nine cases resulted in an indemnity payment. The overall average indemnity payment was $171,478, but that increased to $325,369 when we included in the analysis only those claims that resulted in payment. The largest single indemnity payment was $2.42 million for bilateral arterial injuries after bilateral TKAs that resulted in right below-knee and left above-knee amputations. The insurers’ average expenses to defend the allegations were $66,365; two cases of wounds separate from the surgical site accrued no expenses but resulted in indemnity payments, likely secondary to immediate settlement. There was little correlation between the prepayout defense costs and the eventual payouts (Table 3).

In primary TKA, the average indemnity payment for allegations of nonspecific dissatisfaction or chronic pain was $118,740, but 9 of the 12 cases did not result in payment. The mean cost to defend these claims was $60,940 (Table 3).

In revision TKA, the average indemnity payment was $204,249 (range, $0 to $550,537) for contractures and $134,328 (range, $62,210 to $206,445) for footdrop. However, no payments were made for the cases alleging ongoing unexplained pain or the occurrence of an ankle blister away from the surgical site (Table 4).


We examined a large series of TKAs to determine the most common causes of malpractice claims. In a quest for sources of patient dissatisfaction that could be preventable, we also analyzed the relationship between the indemnity that patients received and the nature of their allegations.

In 2010, approximately 4.7 million individuals in the United States—4.6% of the population aged >50 years—were estimated to be living with a TKA; the prevalence increased with age, to 10.4% at age 80 years. In addition, trends in the numbers of procedures performed indicated a shift to younger patients.[13] With such projected increases, the opportunity for complications, poor outcomes, and dissatisfied patients also will likely increase.[14] Despite high success rates,[3,4,13] the proportion of dissatisfied patients has been quoted as being as high as 28%.[14–16]

Survey studies showed that only obstetricians and general surgeons had greater numbers of claims (12%) than did orthopaedic surgeons (8%), and that after 30 years of practice, the incidence of being sued is over 90 %.[17–19] In a study from Italy, the country with the greatest number of physicians subject to criminal proceedings related to medical malpractice, the highest number of complaints across all specialties related to orthopaedics.[20] In a malpractice claims analysis of all types of orthopaedic procedures, Matsen et al[21] showed that the second most frequently alleged cause, but also the group of allegations with the highest impact on orthopaedic liability, was failure to protect structures in the surgical field.

In Finland, where 17,535 TKAs were entered into a database between 1998 and 2003, male patients and patients aged >65 years were less likely to file claims.[22] This finding also was seen across other subspecialties,[23,24] as well as in our data, with 60% of the claims filed by women and 60% of claims filed by patients aged ≤65 years.

Our study uses data from a single malpractice carrier, but other studies show our results to be consistent across TKAs performed by a wide cross section of orthopaedic surgeons. Upadhyay et al[25] presented a series of surgeon self-reported claims; similar to our findings, theirs showed nerve injury, chronic pain, and infection to be common sources of malpractice claims: 13% of respondents cited nerve injury, 8% cited leg-length discrepancy, 7% cited infection, and 4% cited chronic pain as sources of litigation. In a study of only orthopaedic surgeries, Matsen et al[21] showed that the most common allegations of 58 cases after TKA were implant malposition (19%), followed by failure to diagnose or treat infection (16%) and injury to surrounding structures (14%). This frequency of infection is similar to that in our study, except for a higher rate of malpositioning of implants than in our study.

Similar studies using international databases also have outcomes similar to ours. McWilliams et al,[26] using the NHSLA, also showed that infection and surgical error were common complaints after TKA and that vascular injuries resulted in the highest payments per case. TKA totaled 6% of all orthopaedic claims and 5% of the total costs. Infection was alleged in 16.7% of cases; nonspecific alleged negligence, in 11.2% of cases; surgical technical error, in 11.1% of cases; and neurologic deficit, in 6.3% of cases. In a similar population, 24% of cases were caused by ongoing pain and 18% were caused by infection; 30% of the cases caused by infection resulted in amputation.[16] These results are consistent with our US data over a similar period.

In France, Gibon et al[27] found that the most frequent causes of litigation were infection, neurologic deficit, and nonspecific patient dissatisfaction. That said, the most common reasons for the surgeon to be found liable were delays in the diagnosis or treatment of a complication, infection, and technical error. There were 44 cases of infection and 14 postoperative fatalities, 3 of which followed infection and its treatment. These incidences are far greater than those we found, which may be related to differences between countries in the preoperative antibiotic protocol, diagnostic criteria of infection, or surgical techniques.

Chen et al,[28] using NHSLA data, indicated that there is both a significant increase in the number and, more importantly, an increase in the value of claims after TKA. In a 5-year span, 11% of orthopaedic cases were related to knee surgery (515 of 4,609 total orthopaedic surgeries), and 58% of these (298 of 515 surgeries) involved TKA complications. Litigation success rates were highest after surgical technique errors, such as malalignment (71%), retained drains (100%), and incorrect prosthesis sizing (78%) compared to those after events less under the surgeon’s control, such as infection (42%) or deep vein thrombosis or pulmonary embolism (38%).[28]

In the group of patients in our study, 34 claims were opened for cases performed between 1982 and 1998 and 43 for cases between 1999 and 2012. In contrast, in England, in two periods from 1995 to 2002 and 2003 to 2010, the number of claims increased 46% (232 versus 337 claims, respectively).[26] Claims for alleged negligence increased from 5% to 16%, and claims for technical errors increased by 5%. Although this finding could be caused by methodologic changes in data collection, it also could be secondary to an increase in the general dissatisfaction of patients undergoing TKA or a concerning transition to patients being more litigious.

Universally across all series, the highest amounts of indemnity payments are made after vascular injuries, particularly vascular injuries that lead to amputation,[26,27] followed closely by those that lead to infection[16,26,28]and nerve injury,[26] and followed more distantly by those involving technical error[26,27] and chronic pain.[16,26] A unique aspect of our study is that we were able to compare the indemnity payment to patients with the carrier’s cost to defend the cases. In our study, the life-altering complications (ie, amputation, paralysis) resulted in the highest indemnity payments by far, but in several cases of infection or general dissatisfaction, the cost to the carrier came more from the defense than from the payout. However, we were not given access to the breakdown of those costs.

Although an indirect goal of this study was to limit our exposure to lawsuits, the larger issue is improving patient satisfaction. The source of negligence allegations is frequently a lack of adequate communication in the preoperative consent and postoperative recovery period or suboptimal education of patients and families about the risks and limitations of TKA. Communication skills are critical in the setting of realistic expectations, as is the honest, timely, and appropriately mannered relaying of medical errors.[20,29] Bhutta et al[16] showed that failure to obtain informed consent for the risk of ongoing pain following surgery resulted in an indemnity payment in 29% of claims. However, communication requires time, a precious commodity in a healthcare landscape requiring increased “productivity” (ie, an increased volume of patients seen and treated). In addition, communicating effectively also involves striking a balance between informing patients and scaring them away, a diplomatic skill that traditionally has not been part of orthopaedic training. Nevertheless, an improved commitment to establishing patients’ knowledge of and expectations about the procedure, and of all risks and benefits, including the potential for dissatisfaction or loss of function, may reduce the number of malpractice claims.

To our knowledge, there are no published communication guidelines for orthopaedic surgeons, and there is no established formulation of informed consent that is superior to another. One recent study on the informed consent process for TKA found that 62% of patients felt they had received sufficient information about the TKA procedure, but only 28% reported feeling they had received enough information about complications.[30] In a blinded and randomized group of patients undergoing TKA, Johnson et al[31]found that there was no statistical difference in the level of satisfaction with the consent process for the three study groups: (1) those who received an informed consent and a paper handout explaining the risks and benefits of TKA, (2) those who received the informed consent and the handout, and watched a video on the risks and benefits, or (3) those who received the informed consent, a handout, watched the video, and received formal education by a nurse.

Our study has several limitations. Most importantly, because of the anonymity of the data, we were unable to correlate the likelihood of filing a claim with surgeon practice factors, such as years in practice, fellowship training, or type of practice (ie, academic, group, individual). In addition, the patients in this study were drawn from only one malpractice insurer, in contrast to patients in the database studies of other international groups, in which health data were collected more universally and in a centralized manner, thereby providing a large number of patients available for study.


We looked at a collection of cases from a single malpractice carrier across a 30-year span. Patient dissatisfaction, allegations of improper surgery, wound complications, footdrop, and vascular injuries were the major reasons for malpractice suits after TKA. With the increasing prevalence of TKA, orthopaedic surgeons should continue to focus on both preventing these complications and educating patients preoperatively about the risks of surgery—in particular, incomplete satisfaction and lack of full pain relief. One future consideration could be the creation by a respected orthopaedic society of a standard preoperative template to standardize the informed consent process and strike a comfortable medium between fully informing a patient and losing that patient to fear or competing surgeons.

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