565792
research-article2014
FAIXXX10.1177/1071100714565792Foot & Ankle InternationalWiewiorski et al
Article
Risk Factors for Wound Complications in Patients After Elective Orthopedic Foot and Ankle Surgery
Foot & Ankle International® 2015, Vol. 36(5) 479–487 © The Author(s) 2014 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100714565792 fai.sagepub.com
Martin Wiewiorski, MD*,1, Alexej Barg, MD*,2, Hubert Hoerterer, MD1, Thomas Voellmy1, Heath B. Henninger, PhD3, and Victor Valderrabano, MD PhD1
Abstract Background: The aim of this study was to quantify the incidence of postoperative wound complications in elective foot and ankle surgery as well as the risk factors for postoperative wound complications. Methods: Two hundred ninety-five elective orthopaedic foot and ankle operative procedures were performed in 290 patients between January 2006 and June 2010. A logistic multiple regression model was used to identify independent risk factors for postoperative wound healing complications/infection. Results: The overall prevalence of postoperative wound complications within our cohort was 16.9%. In 4 patients (1.4%) deep infection was diagnosed requiring operative irrigation and debridement. Using a logistic multiple regression model we identified the following statistically independent risk factors: age ≥ 60 years (OR = 8.98, 95% CI = 3.55 to 25.02), tobacco use (OR = 48.77, 95% CI = 15.55 to 139.71), and tourniquet time ≥ 90 minutes (OR = 7.02, 95% CI = 2.77 to 19.32). Conclusion: Patients at risk for postoperative wound healing complications following elective orthopaedic foot and ankle surgery include those with higher age, tobacco use, and prolonged use of tourniquet. Level of Evidence: Prognostic Level III, comparative study. Keywords: foot and ankle surgery, wound healing complications, wound infections, risk factors, tobacco use, use of tourniquet
The overall incidence of postoperative wound complications in elective orthopaedic surgery is low with reported rates between 0.07% and 6.5%.1,4,14,30 However, postoperative wound complications with deep infection may result in malunions or nonunions, amputation, sepsis, and increased mortality.14 Besides the impact on postoperative outcome, the economic impact of postoperative wound complications should not be underestimated.32 Infection at the operative site is 1 of the major reasons for readmission of orthopedic operative patients.8 The incidence of wound complications is well documented for knee and hip surgery.2,3,23,24 However, there is a limited amount of data on postoperative wound complications in patients who have undergone elective orthopedic foot and ankle surgery. The objectives of the present study were to determine wound complication rates in patients who have undergone elective orthopaedic foot and ankle surgery and analyze the independent risk factors for postoperative wound complications.
Methods Patient Demographics and Study Characteristics This prospective study was conducted in accordance with the Declaration of Helsinki and the Guidelines for Good Clinical Practice. The protocol was approved by our ethics committee. All participants provided informed written consent prior to surgery and participation. From January 2006 1
Orthopaedic Department, University Hospital of Basel, Basel, Switzerland 2 Department of Orthopaedics, University of Utah, Salt Lake City, UT, USA 3 Department of Orthopaedics, Harold K. Dunn Orthopaedic Research Laboratory, University of Utah, Salt Lake City, UT, USA *MW and AB contributed equally to this work. Corresponding Author: Alexej Barg, MD, Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA. Email:
[email protected]
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Table 1. Inclusion and Exclusion Criteria for Patient Enrollment. Inclusion Criteria
Primary elective foot and ankle surgery Surgery performed by 1 surgeon Aseptic surgery All follow-ups in our outpatient clinic
Exclusion Criteria
Systemic infection at the time of surgery Foot ulcerations at the time of surgery Vascular disease Surgery due to trauma Revision surgery Previous surgeries of foot/ ankle Isolated ankle arthroscopy Hardware removal
to June 2010, 432 consecutive patients underwent an elective orthopaedic foot and ankle operative procedure. In total, 290 patients (295 operative procedures, 117 men and 173 women) with a mean age of 53.3 ± 16.8 years (range, 14.8 to 86.0 years) were included into this study (see Table 1 for inclusion/exclusion criteria, Table 2 for patient demographics, and Table 3 for surgeries). In 292 of 295 cases (99.0%) an intraoperative “single-shot” antibiotic prophylaxis was performed using cefuroxime 1.5 g i.v. (ZINACEF®; Glaxo Smith Kline AG, Muenchenbuchsee, Switzerland). Operative characteristics are summarized in Table 4.
Clinical Evaluation The patients were seen postoperatively in the clinic by 3 independent reviewers (M.W., A.B., H.H.) who did not perform any surgeries. Postoperative wound complications were defined as the presence of at least 1 of the following findings as adapted from Zgonis et al37: superficial wound dehiscence, severe persistent (over 96 hours) edema and/or erythema, stitch abscess, and wound secretion. Wound infection was classified following the guidelines of Centers for Disease Control and Prevention for superficial incisional and deep incisional operative site infections.21 In patients with clinical signs of postoperative wound complications or wound infection, a multidisciplinary approach including clinical assessment by colleagues from the department of internal medicine was initiated and the final treatment decisions were based on consensus.
Statistical Analysis A Kolmogorov-Smirnov test was performed to verify whether the data were normally distributed. Nonnormally distributed continuous data were compared using Mann–Whitney rank
sum test. The chi-square test was used for comparison of unmatched categorical data. A univariate Cox’s regression test was performed to identify factors associated with an increased incidence of postoperative wound healing complications and infection. These factors included age (≥50, ≥60, ≥70, and ≥80 years), gender, body mass index (BMI) (< 18.5, ≥25, and ≥30 kg/m2), American Society of Anesthesiologists classification7 (ASA ≥ 2 and ASA 3), use of tobacco, diabetes mellitus, type of surgery (more than 2 areas), operative time (≥60, ≥90, ≥120, ≥150, and ≥180 min), tourniquet use, tourniquet time (≥60, ≥90, ≥120, and ≥150 min), use of internal/ external fixation, duration of hospital stay (≤ 3, ≥7, ≥10, and ≥15 days), and postoperative rehabilitation (full weightbearing). The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Factors associated with an increased incidence of postoperative wound healing problems (significance at P ≤ .1) were considered for inclusion in a logistic multiple regression model with stepwise forward and backward variable selection. Those statistically significant (P ≤ .05) factors that remained in the model were considered to be independent predictors of postoperative wound healing problems. The calibration of the model was assessed by comparing the observed and expected risk outcome using a Hosmer–Lemeshow goodness-of-fit test.16 Data were analyzed using SPSS version 20.0 (SPSS Inc, Chicago, IL) and SigmaPlot version 12.5 (Systat Software Inc, San Jose, CA).
Results A wound complication was observed in 46 of 295 (15.6%) procedures (Table 5). In 4 cases (1.4%) a deep wound infection was diagnosed (Table 6). The factors found to be significantly associated with the occurrence of wound complications/infection were age (≥50 and ≥60), obesity (BMI ≥25 and ≥30 kg/m2), use of tobacco, diabetes mellitus, 2 or more surgery sites on the same foot, operative time (≥60, ≥90, and ≥120 min), tourniquet time (≥90 min), and duration of hospital stay (≥7, ≥10, and ≥15 days) (Table 7). The regression model showed that an age of ≥60 years, tobacco use, and tourniquet time ≥90 minutes were independently associated with wound complications (Table 8). The Hosmer–Lemeshow test indicated that the overall model fit was good (P = .872).
Discussion To our knowledge, this is the first study to specifically address the risk factors for postoperative wound healing complications and infections in patients who have undergone elective foot and ankle surgery. In the present study, the incidences of postoperative wound healing complications and
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Wiewiorski et al Table 2. Demographic Data of 293 Patients (298 Feet/Ankles) Who Underwent Primary Elective Foot and Ankle Surgery. Parameter Number ankles/feet (%) Mean age (range) (years) Gender male:female (%) Mean weight (range) (kg) Mean height (range) (cm) Mean BMI (range) (kg/m2) BMI classification (%) Underweight Normal range Overweight Obese American Society of Anesthesiologists classification (%) 1 2 3 4 Tobacco use yes:no (%) Diabetes mellitus yes:no (%) Rheumatoid disease yes:no (%)
All Patients
Wound Complications
No Wound Complications
295 (100) 53.3 (14.8-86.0) 118:177 (40.0:60.0) 75.9 (43-145) 169.8 (135-200) 26.2 (14.8-48.3)
50 (16.9) 62.4 (25.2-86.0) 24:26 (8.1:8.8) 84.4 (51-145) 171.6 (154-200) 28.5 (17.9-48.3)
245 (83.1) 51.5 (14.8-82.0) 94:151 (31.9:51.2) 74.2 (43-135) 169.6 (135-193) 25.8 (14.8-40.2)
7 (2.4) 129 (43.7) 100 (33.9) 59 (20.0)
83 (28.1) 179 (60.7) 32 (10.8) 1 (0.3) 46:249 (15.6:84.4) 19:276 (6.4:93.6) 18:277 (6.1:93.9)
1 (0.3) 13 (4.4) 21 (7.1) 15 (5.1)
6 (2.0) 35 (11.9) 9 (3.1) 0 (0.0) 30:20 (10.2:6.8) 8:42 (2.7:14.2) 2:48 (0.7:16.3)
6 (2.0) 116 (39.3) 79 (26.8) 44 (14.9)
77 (26.1) 144 (48.8) 23 (7.8) 1 (0.3) 16:229 (5.4:77.6) 11:234 (3.7:79.3) 16:229 (5.4:77.6)
P Value —
