Lymphedema Is Severely Underdiagnosed in the Arthroplasty Clinic Population: A Bioimpedance Investigation

Background Lymphedema is a recognized risk factor for postoperative complications after total joint arthroplasty (TJA). Edema from sources other than lymphedema can also contribute to postoperative complications, as preoperative leg edema is known to worsen postoperatively, prolonging recovery and increasing complication risks. Current evidence surrounding lymphedema in the arthroplasty context is scarce, and historical barriers have hindered its diagnosis. Given these limitations, research investigating preoperative identification of patients with lymphedema may have a profound impact on postoperative outcomes in TJA. Questions/purposes (1) What percentage of patients in the highest quintile of extracellular water to total body water (ECW/TBW) ratios were found to have a diagnosis of lymphedema or edema according to ICD-10 codes? (2) Among patients in this group, were there any differences in BMI, ECW/TBW ratios, age, sex, or concurrent diagnoses of hypertension (HTN), diabetes mellitus (DM), and chronic kidney disease (CKD) between those who had a diagnosis and those who did not? Methods Between February 2020 and March 2024, a total of 4133 patients from the hip/knee arthroplasty clinic at the University of Iowa Hospitals & Clinics underwent bioelectrical impedance analysis (BIA) scans. BIA scans were routinely performed preoperatively on all patients undergoing TJA at their initial clinic visit, except for those unable to stand for 60 seconds and/or those with an implanted electronic cardiac device. We considered the top 20% of ECW/TBW ratios as eligible for inclusion in this retrospective study. From this subset, 20% (823) were eligible. Of the entire cohort, 8% (349 of 4133) were excluded because of duplicate records or having their BIA scan performed at a non-TJA clinic, and 1% (2) were excluded because of incorrect height measurements resulting in inaccurate BIA data, leaving 11% (472 of 4133) for final analysis. BIA scans were performed using the InBody 770 and InBody 970 (InBody USA), which have been found to demonstrate good repeatability and validity when compared with the current gold standard: the dual-energy X-ray absorptiometry scan. We reviewed electronic medical records (EMRs) for ICD-10-Clinical Modification codes containing lymphedema (I89) or edema (R60) diagnoses. Because health conditions that impact bodily fluid distribution can potentially confound BIA measurements, patient EMRs were also evaluated for diagnoses of HTN, DM, and CKD to analyze their impact on lymphedema diagnosis. The patients included in the final analysis had a median (range) age of 69 years (63 to 76), with a median (range) BMI of 36.9 kg/m 2 (30.7 to 44.1); 55% (261 of 472) were female. Wilcoxon rank sum testing and chi-square testing were performed to analyze differences in BMI, ECW/TBW leg ratios, sex, age, and diagnosis of concurrent chronic disease (HTN, DM, CKD) between the lymphedema- or edema-diagnosed group and the nondiagnosed group. Results Of the 472 patient charts reviewed, 13% (62) had an active or historical diagnosis of lymphedema or edema. Specifically, 11% (52) were diagnosed with edema alone, 1% (4) with lymphedema alone, 1% (6) with both, and 87% (410) had no such diagnoses. No differences were found between patients with a diagnosis and those without a diagnosis in regard to BMI, ECW/TBW ratio, age, sex, and concurrent diagnoses of potential confounders HTN, DM, and CKD. Conclusion Lymphedema is severely underdiagnosed in patients undergoing TJA. Considering the potential of lymphedema to increase postoperative complications, orthopaedic surgeons should implement routine preoperative screening protocols, such as BIA, to more effectively identify at-risk patients. Future research can investigate the effectiveness of different strategies in reducing postoperative complications in the lymphedematous TJA population. These efforts could ultimately improve recovery and outcomes for patients who undergo TJA. Level of Evidence Level IV, diagnostic study.