EVIDENCE FOR PRACTICE. Evidence Appraisal Score: I A

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1 EVIDENCE FOR PRACTICE Evidence appraisal of Dreyer HC, Owen EC, Strycker LA, et al. Essential amino acid supplementation mitigates muscle atrophy after total knee arthroplasty: a randomized, double- blind, placebo- controlled trial. JBJS Open Access. 2018;(3)2:e oa Evidence Appraisal Score: I A Editor s note: Reading research and incorporating valid research results into practice is a vital part of ensuring that perioperative nursing practice is evidence based. The AORN Research Evidence Appraisal Tools can help perioperative nurses evaluate research. There are three tools for evaluation of the different types of evidence: the Research Evidence Appraisal Tool Study, the Research Evidence Appraisal Tool Summary, and the Non-Research Evidence Appraisal Tool. These tools are used to evaluate the evidence upon which AORN s guidelines are based. The tools can be used to appraise the level of evidence and quality of evidence for a single research study, a summary of multiple research studies, or non-research evidence. Each section of the tool is discussed to help readers understand why the study received a particular appraisal score and what that rating means to perioperative nursing practice. Clinical judgment should be used to determine whether the findings of an individual study are of value and relevance in a particular setting or patient care situation. Individuals intending to put this study s findings into practice are encouraged to review the original article to determine its applicability to their setting. After total knee arthroplasty (TKA), patients must overcome muscle atrophy and weakness before they can safely return to work. Specifically, quadriceps muscle atrophy and weakness are known to compromise balance, reduce functional mobility, and increase the risk for falls. A recent study has shown that amino acid supplementation before and after TKA reduced muscle atrophy in the older adult population. The current researchers previously conducted a proof- of- principle report and found that essential amino acid (EAA) supplementation before and after TKA reduced muscle atrophy when compared with placebo. In the present study, the authors replicated their previous study to include more participants, participants with a AORN, Inc, 2019 AORN Journal 127

2 Evidence for Practice January 2019, Vol. 109, No. 1 broader age range, and participants under the care of more surgeons. They performed a single- center, double- blind, placebo- controlled randomized trial in patients undergoing primary unilateral TKA to document changes in quadriceps and hamstring muscle volume between groups of older adult patients who received either EAA or placebo before and after TKA. Because this is the report of a single research study, the AORN Research Evidence Appraisal Tool Study was used for the evidence appraisal (Figure 1). LEVEL OF EVIDENCE Using the AORN Research Evidence Appraisal Tool Study, the study was classified as level I for level of evidence. The rationale for this classification is explained in the following sections. Intervention/manipulation. Patients between the ages of 50 and 80 years who were scheduled to undergo primary unilateral TKA were eligible for the study. Patients with a history of lower extremity total joint replacement surgery; uncontrolled endocrine disease; heart, kidney, liver, blood, or respiratory disease; peripheral vascular disease; active cancer; or recent treatment with anabolic steroids or oral corticosteroids for more than one week were excluded. Patients who were under the care of four surgeons between January 2015 and September 2016 were randomized in a 1:1 ratio to treatment with EAA or placebo. Control/comparison group. The treatment group comprised patients assigned to receive EAA; the control group comprised patients assigned to placebo. Random assignment. Patients enrolled in the study were stratified by sex and were randomly assigned using a table generated by Random.org to ingest 20 g of EAA (n = 19) or placebo (n = 20) twice daily for seven days preoperatively and for six weeks postoperatively. QUALITY OF EVIDENCE Using the AORN Research Evidence Appraisal Tool Study, this study was classified as A for quality of evidence. The rationale for this classification is explained in the following sections. Purpose/background. The purpose of the study and the research questions were clearly stated. The researchers identified what is known and not known about the research question, including that EAA has been shown to increase muscle in older adults and that EAA supplementation taken before and after TKA has been shown to mitigate muscle atrophy after surgery when compared with placebo. The present study sought to determine whether perioperative administration of EAA would attenuate muscle atrophy after TKA in older adults. Additionally, the researchers wanted to determine if EAA was safe for ingestion in an older adult surgical population. The University of Oregon Institutional Review Board and the PeaceHealth System Institutional Review Board approved the study. The literature review was adequate. Although only 7 of the 29 references listed (24%) were published within the last five years, the references were relevant to the research question. Randomization. The participants were randomly assigned to the intervention and control groups and participants and providers were blinded to the study group. Control. The control group consisted of 20 patients who were randomized to receive placebo. The authors provided baseline information that showed that there were no significant differences between the patients in the treatment group versus the patients in the control group. Both groups were monitored equally preoperatively and postoperatively and were treated equally with the exception of the intervention. This was a single- center study. Intervention(s). The intervention supported the research question and contained sufficient detail to allow for replication. The researchers initiated a placebo or EAA supplementation one week before TKA, which was discontinued on the day of surgery and resumed on the first postoperative day. The treatment was continued for six weeks for a total of 49 days. Sample size. The authors noted that the study was designed with sufficient statistical power primarily to detect differences in the more reliable physiological measurements of muscle volume. However, it may have lacked statistical power to detect functional measures. The study participants comprised 67 older adult patients aged 50 to 80 years. The inclusion and exclusion criteria for the study participants were clear. All study participants were accounted for in the analysis. Sixteen participants in the placebo group and 12 participants in the treatment group were excluded from the primary analysis of 39 patients. 128 AORN Journal

3 January 2019, Vol. 109, No. 1 Evidence for Practice Figure 1. AORN Journal 129

4 Evidence for Practice January 2019, Vol. 109, No. 1 Figure 1. continued 130 AORN Journal

5 January 2019, Vol. 109, No. 1 Evidence for Practice Data collection. The researchers clearly described the methods of data collection. Preoperative blood chemistry, magnetic resonance imaging (MRI), strength and functional mobility, and patient- reported outcome data were collected two to six weeks preoperatively. Functional measures were repeated at two and six weeks postoperatively and MRI assessment and evaluation of patient reported outcomes were performed at six weeks postoperatively. Blood chemistry was monitored on the day of surgery, two days postoperatively, and two and six weeks postoperatively. Placebo or EAA supplementation was initiated one week before TKA, discontinued on the day of surgery, and then continued for six weeks. Research personnel recorded and verified ingestion. The patients recorded their physical activity with an accelorometer and their calorie intake in a three- day food diary. The researchers also described the methods of statistical analysis. They used the Benjamini- Hochberg procedure to adjust P values for multiple comparisons between the EAA group and placebo group outcome variables at two and six weeks. Analyses were performed using SPSS version Results/conclusions. The authors presented two figures and five tables that listed the following information, respectively: a Consolidated Standards of Reporting Trials flow diagram showing the number of patients who were randomly assigned to each group, who were excluded or withdrew from the study, and who were included in the analysis; magnetic resonance imaging scans before TKA and six weeks after TKA in a patient in the placebo group compared with a patient in the EAA group; supplement composition; patient characteristics; treatment effects for MRI-measured quadriceps and hamstring muscle outcomes at six weeks after TKA; treatment effects for functional, strength, and quality-of-life outcomes; and blood test values by treatment group. The content of the tables and the figures were consistent with the article narrative. The authors clearly explained the outcomes of the study. The primary outcome measure was muscle volume. Repeated- measures analyses of variance showed significant changes in mean muscle volume for both the quadriceps and the hamstring muscles from baseline to six weeks postoperatively regardless of the treatment group (P <.05). Quadriceps muscle atrophy was significantly greater in the placebo group compared with the EAA group in both the involved leg ( 13.4% ± 1.9% compared with 8.5% ± 2.5%, P =.033) and the contralateral leg ( 7.2% ± 1.4% compared with 1.5% ± 1.6%; P =.014). Similarly, hamstring muscle atrophy was significantly greater in the placebo group compared with the EAA group in both the involved leg ( 12.2% ± 1.4% compared with 7.4% ± 2.0%; P =.036) and the contralateral leg ( 7.5% ± 1.5% compared with 2.1% ± 1.3%; P =.005). Patients in both groups reported significant decline from baseline functional status at two weeks postoperatively (P <.05). The secondary outcomes (ie, physical activity, caloric intake) showed no significant difference between the groups in terms of average energy expended preoperatively ( ± compared with ± kilocalories/day; P =.24) or at two and six weeks postoperatively. There were no adverse- related study events. The authors conclusions were consistent with the results of the study, which confirmed their previous proof- of- principle study findings. The findings suggested that EAA supplementation is potentially effective for helping older adults to recover from TKA surgery. The researchers concluded that the study findings extend our understanding of the potential beneficial of EAA use in patients managed with TKA. Limitations/future research. The researchers discussed the limitations of their study. They noted that the analyses were limited primarily to the acute perioperative period because previous research has shown that significant muscle loss occurs within the first two weeks after surgery. Secondly, the retention rate of 63.9% was lower than anticipated. However, they noted that the dropout rate did not differ between the two groups. Thirdly, medications used to promote recovery after TKA, such as muscle relaxants, could have influenced the results, but the authors pointed out that the proportion of muscle relaxant users did not differ between the groups, and muscle relaxants did not significantly interact with the treatment group to predict outcomes. Finally, inconsistency in the EAA composition is a limitation that could have affected the results. The researchers recommended that future research should explore muscle volume and functional outcomes across longer follow- up periods, ideally two years or longer. AORN Journal 131

6 Evidence for Practice January 2019, Vol. 109, No. 1 Bias. The study included some safeguards against potential bias, including the double- blinded, placebo- controlled randomized trial design. The researchers did not over- or underestimate the effects of the intervention. Validity. The results of the study were obtained by sound methods, as evidenced by the use of confidence intervals, P values, and common analysis techniques. Generalizability. The results of this study may not be generalizable to every patient undergoing TKA. The results of this study provide additional support of the potential beneficial effects of EAA use in older adult patients undergoing TKA. APPRAISAL RESULTS The AORN Research Evidence Appraisal Tool Study was used to score this study as I A. The study was scored as I for level of evidence because it was a double-blind, placebo-controlled randomized trial. The study was scored as A for quality of evidence because it included a clear purpose, an intervention, a sample size that was designed with sufficient statistical power to detect differences in the more reliable physiological measures of muscle volume, data collection, results, and conclusions. A score of I A indicates that this study represents the best research evidence available and that it is appropriate for perioperative nurses to consider this evidence in guiding their practice. PERIOPERATIVE IMPLICATIONS The results of this study showed that the use of EAA in older adult patients undergoing TKA is safe and potentially effective for helping these patients successfully recover from their TKA. However, the researchers concluded that, although this trial extends our understanding of the potential beneficial effects of EAA in patients, future studies are warranted. Perioperative nurses should be prepared to assist in designing and performing additional studies regarding the use of EAA in patients undergoing TKA. Editor s note: SPSS is a registered trademark of IBM Corporation, Armonk, NY. This article was appraised by George Allen, PhD, MS, BSN, RN, CNOR, CIC, FAPIC, director of Infection Control and Prevention, Brookdale University Hospital Medical Center, and clinical assistant professor, SUNY College of Health Related Professions, Brooklyn, NY. Dr Allen has no declared affiliation that could be perceived as posing a potential conflict of interest in the publication of this article. 132 AORN Journal