J Shoulder Elbow Surg (2015) -, 1-5
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Obesity is associated with increased postoperative complications after operative management of distal humerus fractures Brian C. Werner, MD, Robert B. Rawles, MD, J. Taylor Jobe, MD, A. Bobby Chhabra, MD, Aaron M. Freilich, MD* Department of Orthopaedic Surgery, University of Virginia Health System, Charlottesville, VA, USA Background: Distal humerus fractures commonly require surgical intervention, including open reduction and internal fixation (ORIF) and, more recently in elderly, low-demand individuals, total elbow arthroplasty (TEA). The association of obesity with complications after either of these procedures has not previously been examined. Methods: A national insurance database was queried for ORIF or TEA for management of a distal humerus fracture using procedural and diagnostic codes. Patients in each operative group were then divided into nonobese and obese cohorts. These cohorts were then queried for postoperative complications within 90 days after the surgical procedure using diagnostic and procedural codes. c2 tests were calculated to determine statistical significance, with P < .05 considered significant. Results: A total of 6928 patients who underwent operative management of a distal humerus fracture were identified, including 4215 ORIF and 2713 TEA procedures. The obese ORIF patients had a significantly increased risk of 90-day local (odds ratio [OR], 2.5; P < .0001) and systemic (OR, 5.9; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were significantly higher in the obese ORIF cohort than in nonobese patients. The obese TEA patients had a significantly increased risk of 90-day local (OR, 2.6; P < .0001) and systemic (OR, 4.4; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were higher in the obese TEA cohort than in nonobese patients. Conclusions: Obesity is associated with significantly higher rates of complications after ORIF and TEA for distal humerus fractures than in nonobese patients. Level of evidence: Level III, Retrospective Cohort Design with Large Database, Treatment Study. Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Obesity; distal humerus fractures; open reduction and internal fixation; total elbow arthroplasty; complications
This study is exempt from review by the University of Virginia Institutional Review Board for Health Sciences Research. *Reprint requests: Aaron M. Freilich, MD, Department of Orthopaedic Surgery, University of Virginia Health System, 400 Ray C Hunt Dr, Suite 330, Charlottesville, VA 22908, USA. E-mail address: [email protected] (A.M. Freilich).
Distal humerus fractures are a common injury facing orthopedic surgeons, and treatment of these fractures remains challenging. Fractures about the elbow constitute 7% of adult fractures, with half of these being distal humerus fractures.30 There is an age-related increase of these fractures, especially in women. The optimal treatment
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2 of distal humerus fractures depends on numerous factors, including intra-articular involvement, comminution, alignment, and numerous patient-dependent factors.4,28 Advances in implants have greatly improved the surgical options for and expected outcomes of distal humerus fractures. The most common surgical options are open reduction with internal fixation (ORIF) and total elbow arthroplasty (TEA). Precontoured medial and lateral anatomic locking plates have provided an excellent option for fixation of distal humerus fractures.4 The goal of surgery is to restore anatomic alignment of the articular surface as well as the mechanical alignment of the arm. TEA for fractures is a good option for severely comminuted or very distal intra-articular fractures, particularly in elderly, low-demand individuals.10,16,26,27,34 Despite these advances in treatment, complications still do occur. These complications include both local and systemic events. Local complications include superficial and deep infections, nerve and vascular injuries, malunion, nonunion, hardware failure, joint stiffness, and heterotopic ossification. Systemic complications include deep venous thrombosis (DVT), pulmonary embolism (PE), cerebrovascular accident (CVA), end-organ failure, and nonsurgical site infections such as urinary tract infection (UTI) and pneumonia.2,3,8,9,35,36 The increase in obesity in the United States has become a significant public health concern. Obesity is associated with increased perioperative and postoperative complications after numerous orthopedic procedures.7,11-14,18,20-22,24 This can increase both the cost of care and the burden on an already taxed health care system. There are few existing data examining the association of obesity with complications after surgical treatment of distal humerus fractures, including ORIF and TEA. The purpose of this study was to use a national insurance database to examine the association of obesity with complications after surgically treated distal humerus fractures, including ORIF and TEA. We hypothesized that obesity is associated with increases in complications after these procedures.
Materials and methods All data were derived from a publicly available, subscription database of patients, the PearlDiver patient records database (www.pearldiverinc.com; PearlDiver Inc., Fort Wayne, IN, USA). The database contains procedure volumes, demographics, and average charge information for patients with International Classification of Diseases, Ninth Revision (ICD-9) diagnoses and procedures or Current Procedural Terminology (CPT) codes. Data for this study were derived from the Medicare database within the PearlDiver records, which has >100 million individual patient records from 2005 to 2011. Access to the database was granted by PearlDiver Technologies for the purpose of academic research. The database was stored on a password-protected server maintained by PearlDiver. CPT and ICD-9 codes can be searched in isolation or in combination with one another. The search results
B.C. Werner et al. yield the number of patients with the searched code or combination of codes. For the purposes of this study, the database was queried for 2 common procedures used in the management of distal humerus fractures: ORIF and TEA. The TEA cohort was limited to patients who underwent TEA for a diagnosis of distal humerus fracture using ICD-9 coding. The associated CPT and ICD-9 codes used to define each operative cohort are listed in Supplementary Table I (available on the journal’s website at www.jshoulderelbow.org). Patients in each operative group were then divided into nonobese and obese cohorts using ICD-9 codes for obesity, morbid obesity, and body mass index (BMI) >30 as listed in Supplementary Table II (available on the journal’s website at www.jshoulderelbow.org). The obese and nonobese cohorts for each operative management group were queried for basic demographics including sex, age (80 years), and smoking status. Comorbidities for each cohort were assessed, including diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease, congestive heart failure, coronary artery disease, chronic kidney disease, chronic lung disease, and chronic liver disease using ICD-9 codes for each disease. The obese and nonobese cohorts for each operative management group were then queried for postoperative complications after the surgical procedure using ICD-9 and CPT codes. Complications were pooled into the following categories to yield usable data: local complications within 90 days postoperatively, systemic complications within 90 days postoperatively, infection within 90 days postoperatively (including diagnosis of infection or operative procedure for infection), stiffness within 6 months postoperatively (including diagnosis of stiffness or operative procedure for stiffness, such as manipulation under anesthesia or lysis of adhesions), venous thromboembolism (VTE) within 90 days postoperatively (including DVT and PE) and medical complications within 90 days postoperatively. Local complications included a diagnosis of postoperative stiffness, postoperative stiffness requiring manipulation under anesthesia or lysis of adhesions, diagnosis of postoperative infection, and need for postoperative irrigation and debridement. Systemic complications included PE, DVT, acute myocardial infarction, respiratory failure, acute postoperative CVA, UTI, pneumonia, acute renal failure, and cholecystitis. Postoperative VTE (including PE and DVT) and postoperative infection (including diagnosis or irrigation and debridement) were also separately queried. The associated ICD-9 and CPT codes for each postoperative complication are provided in Supplementary Table I (available on the journal’s website at www.jshoulderelbow.org). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each comparison between obese and nonobese cohorts. c2 tests were calculated to determine statistical significance, with P < .05 considered significant.
Results A total of 6928 unique patients who underwent operative management of a distal humerus fracture were identified from 2005 to 2011, including 4215 ORIF and 2713 TEA procedures. Overall, 1162 patients (16.8%) were coded obese or morbidly obese. The nonobese and obese cohorts
Obesity and distal humerus fractures
3
Table I ORIF for distal humerus fractures: 90-day postoperative complication rates
Table II TEA for distal humerus fractures: 90-day postoperative complication rates
Complications Nonobese Obese Odds ratio (BMI < 30) (BMI > 30) (95% CI)
Complications Nonobese Obese Odds ratio (BMI < 30) (BMI > 30) (95% CI)
Total No. Local) (90 days) Systemicy (90 days) Infection (90 days) Stiffness (6 months) VTE (90 days)
3560 655 108 (3.0%) 48 (7.3%)
Total No. 2206 Local) 75 (3.4%) (90 days) Systemicy 112 (5.1%) (90 days) Infection 43 (1.9%) (90 days) Stiffness 102 (4.6%) (6 months) VTE (90 days) 20 (0.9%)
Medicalz (90 days)
174 (4.9%)
184 (5.2%) 34 (1.0%) 191 (5.4%) 23 (0.6%)
Obese vs. nonobese 2.5 (1.8-3.6) P < .0001 159 (24.3%) 5.9 (4.7-7.4) P < .0001 26 (4.0%) 4.3 (2.6-7.2) P < .0001 42 (6.4%) 1.2 (0.9-1.7) P ¼ .325 18 (2.7%) 4.3 (2.3-8.1) P < .0001 152 (23.2%) 5.9 (4.6-7.5) P < .0001
Medicalz (90 days)
507 42 (8.3%)
Obese vs. nonobese 2.6 (1.7-3.8) P < .0001 97 (19.1%) 4.4 (3.3-5.9) P < .0001 33 (6.5%) 3.5 (2.2-5.6) P < .0001 31 (6.1%) 1.3 (0.9-2.0) P ¼ .198 17 (3.4%) 3.8 (2.0-7.3) P < .0001 95 (4.3%) 86 (17.0%) 4.5 (3.3-6.2) P < .0001
ORIF, open reduction and internal fixation; BMI, body mass index; CI, confidence interval; VTE, venous thromboembolism. ) Local complications: postoperative infection, postoperative irrigation and debridement, stiffness, postoperative manipulation under anesthesia, postoperative lysis of adhesions. y Systemic complications: deep venous thrombosis, pulmonary embolism, myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis. z Medical complications: myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis.
TEA, total elbow arthroplasty; BMI, body mass index; CI, confidence interval; VTE, venous thromboembolism. ) Local complications: postoperative infection, postoperative irrigation and debridement, stiffness, postoperative manipulation under anesthesia, postoperative lysis of adhesions. y Systemic complications: deep venous thrombosis, pulmonary embolism, myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis. z Medical complications: myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis.
for each operative management group were significantly different in terms of most medical comorbidities (Supplementary Table II, available on the journal’s website at www.jshoulderelbow.org). Within the ORIF group, 655 patients (15.5%) were coded obese. The obese ORIF patients had a significantly increased risk of 90-day local (OR, 2.5; 95% CI, 1.8-3.6; P < .0001) and systemic (OR, 5.9; 95% CI, 4.7-7.4; P < .0001) complications (Table I). The rate of postoperative infection in the obese ORIF cohort (4.0%) was significantly higher than the rate in nonobese patients (1.0%), yielding an OR of 4.3 (95% CI, 2.6-7.2; P < .0001; Table I). Both VTE (OR, 4.3; 95% CI, 2.3-8.1; P < .0001) and medical complications (OR, 5.9; 95% CI, 4.6-7.5; P < .0001) were significantly higher in obese ORIF patients (Table I). There was not a statistically significant difference in the rate of postoperative stiffness within 6 months postoperatively between obese and nonobese ORIF patients. In the TEA group, 507 patients (18.7%) were coded obese. The obese TEA patients had a significantly increased risk of 90-day local (OR, 2.6; 95% CI, 1.7-3.8; P < .0001) and systemic (OR, 4.4; 95% CI, 3.3-5.9; P < .0001) complications (Table II). The rate of postoperative infection in the obese TEA cohort (6.5%) was higher than the rate in nonobese patients (1.9%), yielding an OR of 3.5 (95% CI, 2.2-5.6; P < .0001; Table II). The rate of postoperative stiffness within 6 months
postoperatively in obese patients undergoing TEA was not significantly different from that in nonobese patients. Both VTE (OR, 3.8; 95% CI, 2.0-7.3; P < .0001) and medical complications (OR, 4.5; 95% CI, 3.3-6.2; P < .0001) were significantly higher in obese TEA patients (Table II).
Discussion Obesity has emerged as a common comorbidity for patients requiring orthopedic surgery, incurring a substantial impact on health care system resources. Although it has been stable during the last decade, prevalence has been estimated as high as 35.5% in men and 35.8% in women when it is defined as BMI >30.11 The incidence of associated medical comorbidities, including diabetes mellitus, cardiovascular disease, hypertension, hyperlipidemia, cerebrovascular disease, obstructive sleep apnea, and gallbladder disease, has been well described.5,6,19,23,25,31 These conditions likely increase risk of postoperative medical and surgical complications in this population. Both the TEA and ORIF cohorts demonstrated significantly increased rates of diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease, congestive heart failure, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, and chronic liver disease compared with nonobese patients. Whereas both cohorts demonstrated
4 similar demographics, TEA patients were older, which is an expected finding, given that older age is typically a requisite to consideration of arthroplasty for distal humerus fractures. The effect of obesity on orthopedic surgery has received recent attention in the literature, most consistently with lower extremity arthroplasty but more recently in upper extremity surgery including conventional and reverse total shoulder arthroplasty and TEA.1-3,18,29,32,37 Evidence has been lacking with regard to the risk of obesity in the treatment of upper extremity trauma. In this study, we examined a national insurance database for trends in medical and surgical complications after operative treatment of distal humerus fractures. The data for lower extremity arthroplasty are conflicting; however, they do suggest increased local and systemic complication rates as well as increased length of hospital stay and greater chance of atypical discharge in obese patients.1-3,29,32,33 Foran et al demonstrated lower patient-reported outcomes and higher revision rates in obese patients, with only 88% of obese patients compared with 99% of patients with normal BMI achieving a Knee Society score of >80%.12 D’Apuzzo et al demonstrated small but significant increases in UTI, wound dehiscence, infection, and anemia; however, rates of complications of the cardiac, peripheral vascular, respiratory, gastrointestinal, and central nervous systems and of hematoma and DVT did not appear to increase in morbidly obese patients when matched for other comorbidities.7 Also noted was a significant increased perioperative mortality rate in morbidly obese patients. Our data analysis demonstrates higher incidence of both local and systemic complications in obese patients in both the TEA and ORIF groups within the first 90 postoperative days. Medical complications such as VTE demonstrated an OR of 3.8 in obese patients in our study. Significantly higher rates of medical complications including myocardial infarction, respiratory failure, CVA, UTI, pneumonia, acute renal failure, and cholecystitis were found, with 23.2% vs. 4.9% in the ORIF group and 17.0% vs. 4.3% in the TEA group. Similar findings have been demonstrated in upper extremity arthroplasty; obese patients undergoing total shoulder arthroplasty have demonstrated higher rates of respiratory complications, longer hospital stay, and increased cost.18 Recent data regarding ORIF of proximal humerus fractures demonstrated similar results, including a substantial increase in local and systemic complications postoperatively.37 Obesity is often clustered with other medical comorbidities and thus is difficult to isolate as an independent risk factor. Other studies focus on the metabolic syndrome, defined as a BMI >30 kg/m2 as well as two of the following: hypertriglyceridemia, hyperlipidemia, diabetes mellitus, or hypertension. This cluster of diagnoses has been demonstrated to lead to increased rates of major complications, including cardiac complications, DVT, respiratory complications, and UTI, as well as increased surgical time, hospital cost, and discharge to a rehabilitation facility.15,17
B.C. Werner et al. Our study is limited by the nature of using a large insurance database. Whereas ICD-9 and CPT coding for TEA and ORIF of distal humerus fractures is specific, we have no way of controlling for variations in coding among practitioners. Also, this type of analysis cannot identify cause and effect relationship; with the available data, it was not possible to separate complications related and unrelated to the distal humerus fracture specifically. We attempted to limit this by defining a specific postoperative period during which complications are routinely associated with the procedure. Also, we were not able to separate BMI or obesity as an independent risk factor without confounding results with associated comorbidities. Despite these limitations, our methods provide a large cohort and sufficient power to detect statistically significant differences relevant to the study.
Conclusions Obesity is associated with significantly higher rates of complications after ORIF and TEA for distal humerus fractures compared with those in nonobese patients, including local complications, systemic complications, infection, and VTE. In an evolving health care environment, it will likely become imperative to limit and to stratify cost by recognizing and defining complication risk. Whereas these findings often do not influence the indication for surgery in traumatic injuries, they do prove useful for counseling of patients and perioperative management.
Disclaimer The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Supplementary data Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.jse.2015.04.019.
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Obesity is associated with increased postoperative complications after operative management of distal humerus fractures Brian C. Werner, MD, Robert B. Rawles, MD, J. Taylor Jobe, MD, A. Bobby Chhabra, MD, Aaron M. Freilich, MD* Department of Orthopaedic Surgery, University of Virginia Health System, Charlottesville, VA, USA Background: Distal humerus fractures commonly require surgical intervention, including open reduction and internal fixation (ORIF) and, more recently in elderly, low-demand individuals, total elbow arthroplasty (TEA). The association of obesity with complications after either of these procedures has not previously been examined. Methods: A national insurance database was queried for ORIF or TEA for management of a distal humerus fracture using procedural and diagnostic codes. Patients in each operative group were then divided into nonobese and obese cohorts. These cohorts were then queried for postoperative complications within 90 days after the surgical procedure using diagnostic and procedural codes. c2 tests were calculated to determine statistical significance, with P < .05 considered significant. Results: A total of 6928 patients who underwent operative management of a distal humerus fracture were identified, including 4215 ORIF and 2713 TEA procedures. The obese ORIF patients had a significantly increased risk of 90-day local (odds ratio [OR], 2.5; P < .0001) and systemic (OR, 5.9; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were significantly higher in the obese ORIF cohort than in nonobese patients. The obese TEA patients had a significantly increased risk of 90-day local (OR, 2.6; P < .0001) and systemic (OR, 4.4; P < .0001) complications. The rates of postoperative infection, venous thromboembolism, and medical complications were higher in the obese TEA cohort than in nonobese patients. Conclusions: Obesity is associated with significantly higher rates of complications after ORIF and TEA for distal humerus fractures than in nonobese patients. Level of evidence: Level III, Retrospective Cohort Design with Large Database, Treatment Study. Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Keywords: Obesity; distal humerus fractures; open reduction and internal fixation; total elbow arthroplasty; complications
This study is exempt from review by the University of Virginia Institutional Review Board for Health Sciences Research. *Reprint requests: Aaron M. Freilich, MD, Department of Orthopaedic Surgery, University of Virginia Health System, 400 Ray C Hunt Dr, Suite 330, Charlottesville, VA 22908, USA. E-mail address: [email protected] (A.M. Freilich).
Distal humerus fractures are a common injury facing orthopedic surgeons, and treatment of these fractures remains challenging. Fractures about the elbow constitute 7% of adult fractures, with half of these being distal humerus fractures.30 There is an age-related increase of these fractures, especially in women. The optimal treatment
1058-2746/$ - see front matter Ó 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. http://dx.doi.org/10.1016/j.jse.2015.04.019
2 of distal humerus fractures depends on numerous factors, including intra-articular involvement, comminution, alignment, and numerous patient-dependent factors.4,28 Advances in implants have greatly improved the surgical options for and expected outcomes of distal humerus fractures. The most common surgical options are open reduction with internal fixation (ORIF) and total elbow arthroplasty (TEA). Precontoured medial and lateral anatomic locking plates have provided an excellent option for fixation of distal humerus fractures.4 The goal of surgery is to restore anatomic alignment of the articular surface as well as the mechanical alignment of the arm. TEA for fractures is a good option for severely comminuted or very distal intra-articular fractures, particularly in elderly, low-demand individuals.10,16,26,27,34 Despite these advances in treatment, complications still do occur. These complications include both local and systemic events. Local complications include superficial and deep infections, nerve and vascular injuries, malunion, nonunion, hardware failure, joint stiffness, and heterotopic ossification. Systemic complications include deep venous thrombosis (DVT), pulmonary embolism (PE), cerebrovascular accident (CVA), end-organ failure, and nonsurgical site infections such as urinary tract infection (UTI) and pneumonia.2,3,8,9,35,36 The increase in obesity in the United States has become a significant public health concern. Obesity is associated with increased perioperative and postoperative complications after numerous orthopedic procedures.7,11-14,18,20-22,24 This can increase both the cost of care and the burden on an already taxed health care system. There are few existing data examining the association of obesity with complications after surgical treatment of distal humerus fractures, including ORIF and TEA. The purpose of this study was to use a national insurance database to examine the association of obesity with complications after surgically treated distal humerus fractures, including ORIF and TEA. We hypothesized that obesity is associated with increases in complications after these procedures.
Materials and methods All data were derived from a publicly available, subscription database of patients, the PearlDiver patient records database (www.pearldiverinc.com; PearlDiver Inc., Fort Wayne, IN, USA). The database contains procedure volumes, demographics, and average charge information for patients with International Classification of Diseases, Ninth Revision (ICD-9) diagnoses and procedures or Current Procedural Terminology (CPT) codes. Data for this study were derived from the Medicare database within the PearlDiver records, which has >100 million individual patient records from 2005 to 2011. Access to the database was granted by PearlDiver Technologies for the purpose of academic research. The database was stored on a password-protected server maintained by PearlDiver. CPT and ICD-9 codes can be searched in isolation or in combination with one another. The search results
B.C. Werner et al. yield the number of patients with the searched code or combination of codes. For the purposes of this study, the database was queried for 2 common procedures used in the management of distal humerus fractures: ORIF and TEA. The TEA cohort was limited to patients who underwent TEA for a diagnosis of distal humerus fracture using ICD-9 coding. The associated CPT and ICD-9 codes used to define each operative cohort are listed in Supplementary Table I (available on the journal’s website at www.jshoulderelbow.org). Patients in each operative group were then divided into nonobese and obese cohorts using ICD-9 codes for obesity, morbid obesity, and body mass index (BMI) >30 as listed in Supplementary Table II (available on the journal’s website at www.jshoulderelbow.org). The obese and nonobese cohorts for each operative management group were queried for basic demographics including sex, age (80 years), and smoking status. Comorbidities for each cohort were assessed, including diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease, congestive heart failure, coronary artery disease, chronic kidney disease, chronic lung disease, and chronic liver disease using ICD-9 codes for each disease. The obese and nonobese cohorts for each operative management group were then queried for postoperative complications after the surgical procedure using ICD-9 and CPT codes. Complications were pooled into the following categories to yield usable data: local complications within 90 days postoperatively, systemic complications within 90 days postoperatively, infection within 90 days postoperatively (including diagnosis of infection or operative procedure for infection), stiffness within 6 months postoperatively (including diagnosis of stiffness or operative procedure for stiffness, such as manipulation under anesthesia or lysis of adhesions), venous thromboembolism (VTE) within 90 days postoperatively (including DVT and PE) and medical complications within 90 days postoperatively. Local complications included a diagnosis of postoperative stiffness, postoperative stiffness requiring manipulation under anesthesia or lysis of adhesions, diagnosis of postoperative infection, and need for postoperative irrigation and debridement. Systemic complications included PE, DVT, acute myocardial infarction, respiratory failure, acute postoperative CVA, UTI, pneumonia, acute renal failure, and cholecystitis. Postoperative VTE (including PE and DVT) and postoperative infection (including diagnosis or irrigation and debridement) were also separately queried. The associated ICD-9 and CPT codes for each postoperative complication are provided in Supplementary Table I (available on the journal’s website at www.jshoulderelbow.org). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each comparison between obese and nonobese cohorts. c2 tests were calculated to determine statistical significance, with P < .05 considered significant.
Results A total of 6928 unique patients who underwent operative management of a distal humerus fracture were identified from 2005 to 2011, including 4215 ORIF and 2713 TEA procedures. Overall, 1162 patients (16.8%) were coded obese or morbidly obese. The nonobese and obese cohorts
Obesity and distal humerus fractures
3
Table I ORIF for distal humerus fractures: 90-day postoperative complication rates
Table II TEA for distal humerus fractures: 90-day postoperative complication rates
Complications Nonobese Obese Odds ratio (BMI < 30) (BMI > 30) (95% CI)
Complications Nonobese Obese Odds ratio (BMI < 30) (BMI > 30) (95% CI)
Total No. Local) (90 days) Systemicy (90 days) Infection (90 days) Stiffness (6 months) VTE (90 days)
3560 655 108 (3.0%) 48 (7.3%)
Total No. 2206 Local) 75 (3.4%) (90 days) Systemicy 112 (5.1%) (90 days) Infection 43 (1.9%) (90 days) Stiffness 102 (4.6%) (6 months) VTE (90 days) 20 (0.9%)
Medicalz (90 days)
174 (4.9%)
184 (5.2%) 34 (1.0%) 191 (5.4%) 23 (0.6%)
Obese vs. nonobese 2.5 (1.8-3.6) P < .0001 159 (24.3%) 5.9 (4.7-7.4) P < .0001 26 (4.0%) 4.3 (2.6-7.2) P < .0001 42 (6.4%) 1.2 (0.9-1.7) P ¼ .325 18 (2.7%) 4.3 (2.3-8.1) P < .0001 152 (23.2%) 5.9 (4.6-7.5) P < .0001
Medicalz (90 days)
507 42 (8.3%)
Obese vs. nonobese 2.6 (1.7-3.8) P < .0001 97 (19.1%) 4.4 (3.3-5.9) P < .0001 33 (6.5%) 3.5 (2.2-5.6) P < .0001 31 (6.1%) 1.3 (0.9-2.0) P ¼ .198 17 (3.4%) 3.8 (2.0-7.3) P < .0001 95 (4.3%) 86 (17.0%) 4.5 (3.3-6.2) P < .0001
ORIF, open reduction and internal fixation; BMI, body mass index; CI, confidence interval; VTE, venous thromboembolism. ) Local complications: postoperative infection, postoperative irrigation and debridement, stiffness, postoperative manipulation under anesthesia, postoperative lysis of adhesions. y Systemic complications: deep venous thrombosis, pulmonary embolism, myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis. z Medical complications: myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis.
TEA, total elbow arthroplasty; BMI, body mass index; CI, confidence interval; VTE, venous thromboembolism. ) Local complications: postoperative infection, postoperative irrigation and debridement, stiffness, postoperative manipulation under anesthesia, postoperative lysis of adhesions. y Systemic complications: deep venous thrombosis, pulmonary embolism, myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis. z Medical complications: myocardial infarction, respiratory failure, cerebrovascular accident, urinary tract infection, pneumonia, acute renal failure, cholecystitis.
for each operative management group were significantly different in terms of most medical comorbidities (Supplementary Table II, available on the journal’s website at www.jshoulderelbow.org). Within the ORIF group, 655 patients (15.5%) were coded obese. The obese ORIF patients had a significantly increased risk of 90-day local (OR, 2.5; 95% CI, 1.8-3.6; P < .0001) and systemic (OR, 5.9; 95% CI, 4.7-7.4; P < .0001) complications (Table I). The rate of postoperative infection in the obese ORIF cohort (4.0%) was significantly higher than the rate in nonobese patients (1.0%), yielding an OR of 4.3 (95% CI, 2.6-7.2; P < .0001; Table I). Both VTE (OR, 4.3; 95% CI, 2.3-8.1; P < .0001) and medical complications (OR, 5.9; 95% CI, 4.6-7.5; P < .0001) were significantly higher in obese ORIF patients (Table I). There was not a statistically significant difference in the rate of postoperative stiffness within 6 months postoperatively between obese and nonobese ORIF patients. In the TEA group, 507 patients (18.7%) were coded obese. The obese TEA patients had a significantly increased risk of 90-day local (OR, 2.6; 95% CI, 1.7-3.8; P < .0001) and systemic (OR, 4.4; 95% CI, 3.3-5.9; P < .0001) complications (Table II). The rate of postoperative infection in the obese TEA cohort (6.5%) was higher than the rate in nonobese patients (1.9%), yielding an OR of 3.5 (95% CI, 2.2-5.6; P < .0001; Table II). The rate of postoperative stiffness within 6 months
postoperatively in obese patients undergoing TEA was not significantly different from that in nonobese patients. Both VTE (OR, 3.8; 95% CI, 2.0-7.3; P < .0001) and medical complications (OR, 4.5; 95% CI, 3.3-6.2; P < .0001) were significantly higher in obese TEA patients (Table II).
Discussion Obesity has emerged as a common comorbidity for patients requiring orthopedic surgery, incurring a substantial impact on health care system resources. Although it has been stable during the last decade, prevalence has been estimated as high as 35.5% in men and 35.8% in women when it is defined as BMI >30.11 The incidence of associated medical comorbidities, including diabetes mellitus, cardiovascular disease, hypertension, hyperlipidemia, cerebrovascular disease, obstructive sleep apnea, and gallbladder disease, has been well described.5,6,19,23,25,31 These conditions likely increase risk of postoperative medical and surgical complications in this population. Both the TEA and ORIF cohorts demonstrated significantly increased rates of diabetes mellitus, obstructive sleep apnea, hyperlipidemia, hypertension, peripheral vascular disease, congestive heart failure, coronary artery disease, chronic kidney disease, chronic obstructive pulmonary disease, and chronic liver disease compared with nonobese patients. Whereas both cohorts demonstrated
4 similar demographics, TEA patients were older, which is an expected finding, given that older age is typically a requisite to consideration of arthroplasty for distal humerus fractures. The effect of obesity on orthopedic surgery has received recent attention in the literature, most consistently with lower extremity arthroplasty but more recently in upper extremity surgery including conventional and reverse total shoulder arthroplasty and TEA.1-3,18,29,32,37 Evidence has been lacking with regard to the risk of obesity in the treatment of upper extremity trauma. In this study, we examined a national insurance database for trends in medical and surgical complications after operative treatment of distal humerus fractures. The data for lower extremity arthroplasty are conflicting; however, they do suggest increased local and systemic complication rates as well as increased length of hospital stay and greater chance of atypical discharge in obese patients.1-3,29,32,33 Foran et al demonstrated lower patient-reported outcomes and higher revision rates in obese patients, with only 88% of obese patients compared with 99% of patients with normal BMI achieving a Knee Society score of >80%.12 D’Apuzzo et al demonstrated small but significant increases in UTI, wound dehiscence, infection, and anemia; however, rates of complications of the cardiac, peripheral vascular, respiratory, gastrointestinal, and central nervous systems and of hematoma and DVT did not appear to increase in morbidly obese patients when matched for other comorbidities.7 Also noted was a significant increased perioperative mortality rate in morbidly obese patients. Our data analysis demonstrates higher incidence of both local and systemic complications in obese patients in both the TEA and ORIF groups within the first 90 postoperative days. Medical complications such as VTE demonstrated an OR of 3.8 in obese patients in our study. Significantly higher rates of medical complications including myocardial infarction, respiratory failure, CVA, UTI, pneumonia, acute renal failure, and cholecystitis were found, with 23.2% vs. 4.9% in the ORIF group and 17.0% vs. 4.3% in the TEA group. Similar findings have been demonstrated in upper extremity arthroplasty; obese patients undergoing total shoulder arthroplasty have demonstrated higher rates of respiratory complications, longer hospital stay, and increased cost.18 Recent data regarding ORIF of proximal humerus fractures demonstrated similar results, including a substantial increase in local and systemic complications postoperatively.37 Obesity is often clustered with other medical comorbidities and thus is difficult to isolate as an independent risk factor. Other studies focus on the metabolic syndrome, defined as a BMI >30 kg/m2 as well as two of the following: hypertriglyceridemia, hyperlipidemia, diabetes mellitus, or hypertension. This cluster of diagnoses has been demonstrated to lead to increased rates of major complications, including cardiac complications, DVT, respiratory complications, and UTI, as well as increased surgical time, hospital cost, and discharge to a rehabilitation facility.15,17
B.C. Werner et al. Our study is limited by the nature of using a large insurance database. Whereas ICD-9 and CPT coding for TEA and ORIF of distal humerus fractures is specific, we have no way of controlling for variations in coding among practitioners. Also, this type of analysis cannot identify cause and effect relationship; with the available data, it was not possible to separate complications related and unrelated to the distal humerus fracture specifically. We attempted to limit this by defining a specific postoperative period during which complications are routinely associated with the procedure. Also, we were not able to separate BMI or obesity as an independent risk factor without confounding results with associated comorbidities. Despite these limitations, our methods provide a large cohort and sufficient power to detect statistically significant differences relevant to the study.
Conclusions Obesity is associated with significantly higher rates of complications after ORIF and TEA for distal humerus fractures compared with those in nonobese patients, including local complications, systemic complications, infection, and VTE. In an evolving health care environment, it will likely become imperative to limit and to stratify cost by recognizing and defining complication risk. Whereas these findings often do not influence the indication for surgery in traumatic injuries, they do prove useful for counseling of patients and perioperative management.
Disclaimer The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.
Supplementary data Supplementary data related to this article can be found at http://dx.doi.org/10.1016/j.jse.2015.04.019.
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