{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T10:43:10Z","timestamp":1788777790933,"version":"build-2803163510"},"reference-count":54,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T00:00:00Z","timestamp":1774310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Quadriceps weakness and atrophy are common in patients with knee osteoarthritis and can persist after total knee arthroplasty (TKA), affecting functional recovery. Localized bioelectrical impedance analysis (L-BIA) allows non-invasive assessment of muscle status through resistance (R) and reactance (Xc), reflecting muscle composition and cell integrity. This study investigated longitudinal changes in quadriceps Xc following TKA and their association with functional outcomes.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Twenty-five patients undergoing unilateral TKA were evaluated preoperatively and at 6 and 12 months postoperatively. L-BIA parameters (R and Xc) were measured in the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF). Functional outcomes were assessed using the Knee Society Score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Interlimb comparisons and predictive performance of Xc for functional recovery were analyzed using ROC curves, Gini indices, and Kolmogorov\u2013Smirnov statistics.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>R values remained stable across all muscles postoperatively (P &amp;gt; 0.05). Xc values significantly decreased at 6 months in VM and RF: P &amp;lt; 0.01; VL: P = 0.04 and recovered by 12 months to pre-TKA levels, with greater percentage changes in VM and VL than RF. Also, pre-TKA, Xc was lower in the operated limb compared to the contralateral side (P &amp;lt; 0.01). By 12 months, Xc in VM and RF was similar between limbs, while VL remained slightly lower in the operated leg. ROC analysis showed excellent predictive performance of Xc for WOMAC outcomes (VM and VL Gini = 0.909; K-S = 0.955), with optimal cut-offs of 15.65 \u03a9 and 14.3 \u03a9, respectively. Functional improvements were most pronounced in the first 6 months and correlated with Xc recovery, particularly in VM at 12 months.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Quadriceps Xc measured by L-BIA decreases initially after TKA but recovers by 12 months, paralleling improvements in pain and function. Xc provides a sensitive, non-invasive biophysical parameter for monitoring quadriceps muscle recovery and may inform individualized rehabilitation strategies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fphys.2026.1745998","type":"journal-article","created":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T05:25:19Z","timestamp":1774329919000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":1,"title":["Localized bioimpedance reactance as a biophysical parameter of muscle recovery following total knee arthroplasty: a prospective self-controlled study"],"prefix":"10.3389","volume":"17","author":[{"given":"Gloria","family":"Pedemonte-Parram\u00f3n","sequence":"first","affiliation":[{"name":"Department of Orthopedic Surgery and Traumatology, Hospital Universitari Germans Trias i Pujol","place":["Barcelona, Spain"]},{"name":"Department of Surgery, Universitat Aut\u00f2noma de Barcelona, Edifici U, Campus UAB","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lexa","family":"Nescolarde","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Universitat Polit\u00e8cnica de Catalunya","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ester","family":"Garc\u00eda-Oltra","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery and Traumatology, Hospital Universitari Germans Trias i Pujol","place":["Barcelona, Spain"]},{"name":"Department of Surgery, Universitat Aut\u00f2noma de Barcelona, Edifici U, Campus UAB","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vicente","family":"L\u00f3pez-P\u00e9rez","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery and Traumatology, Hospital Universitari Germans Trias i Pujol","place":["Barcelona, Spain"]},{"name":"Department of Surgery, Universitat Aut\u00f2noma de Barcelona, Edifici U, Campus UAB","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francisco","family":"Aliaga-Ordu\u00f1a","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery and Traumatology, Hospital Universitari Germans Trias i Pujol","place":["Barcelona, Spain"]},{"name":"Department of Surgery, Universitat Aut\u00f2noma de Barcelona, Edifici U, Campus UAB","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jos\u00e9 A.","family":"Hern\u00e1ndez-Hermoso","sequence":"additional","affiliation":[{"name":"Department of Orthopedic Surgery and Traumatology, Hospital Universitari Germans Trias i Pujol","place":["Barcelona, Spain"]},{"name":"Department of Surgery, Universitat Aut\u00f2noma de Barcelona, Edifici U, Campus UAB","place":["Barcelona, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,3,24]]},"reference":[{"key":"B1","first-page":"7","article-title":"Osteoarthrosis of the knee. A radiographic investigation","volume":"277","author":"Ahlb\u00e4ck","year":"1968","journal-title":"Acta Radiol. Diagn Stockh."},{"key":"B2","first-page":"1833","article-title":"Validation study of WOMAC: a health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee","volume":"15","author":"Bellamy","year":"1988","journal-title":"J. Rheumatol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"63","DOI":"10.4081\/BR.2021.63","article-title":"Correlation between pain and weakness of vastus medialis evaluated by ultrasound in total knee arthroplasty","volume":"3","author":"Boccaccio","year":"2021","journal-title":"Beyond Rheumatol."},{"key":"B4","doi-asserted-by":"publisher","first-page":"64","DOI":"10.1186\/1471-2474-9-64","article-title":"The relative timing of VMO and VL in the aetiology of anterior knee pain: a systematic review and meta-analysis","volume":"9","author":"Chester","year":"2008","journal-title":"BMC Musculoskelet. Disord."},{"key":"B5","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/S40064-015-1468-7","article-title":"Limb volume measurements: comparison of accuracy and decisive parameters of the most used present methods","volume":"4","author":"Chromy","year":"2015","journal-title":"Springerplus"},{"key":"B6","doi-asserted-by":"publisher","first-page":"7","DOI":"10.1093\/ajcn\/48.1.7","article-title":"Specific resistivity used to estimate fat-free mass from segmental body measures of bioelectric impedance","volume":"48","author":"Chumlea","year":"1988","journal-title":"Am. J. Clin. Nutr."},{"key":"B7","doi-asserted-by":"publisher","first-page":"649","DOI":"10.1152\/physrev.2000.80.2.649","article-title":"Human body composition: in vivo methods","volume":"80","author":"Ellis","year":"2000","journal-title":"Physiol. Rev."},{"key":"B8","doi-asserted-by":"publisher","first-page":"388S","DOI":"10.1093\/ajcn\/64.3.388S","article-title":"Whole-body impedance--what does it measure?","volume":"64","author":"Foster","year":"1996","journal-title":"Am. J. Clin. Nutr."},{"key":"B9","doi-asserted-by":"publisher","first-page":"3150","DOI":"10.3390\/JCM14093150","article-title":"Muscle activation and mobility after robotic total knee arthroplasty: insights from early postoperative recovery","volume":"14","author":"Garc\u00eda-Sanz","year":"2025","journal-title":"J. Clin. Med."},{"key":"B10","doi-asserted-by":"publisher","first-page":"15","DOI":"10.1016\/J.ARTH.2008.06.014","article-title":"Quadriceps muscle function in primary total knee arthroplasty","volume":"23","author":"Greene","year":"2008","journal-title":"J. Arthroplasty"},{"key":"B11","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1097\/00003086-198911000-00004","article-title":"Rationale of the knee society clinical rating system","author":"Insall","year":"1989","journal-title":"Clin. Orthop. Relat. Res."},{"key":"B12","doi-asserted-by":"publisher","first-page":"3618","DOI":"10.3390\/JCM11133618","article-title":"Do preoperative vastus medialis volume and quality affect functional outcomes after total knee arthroplasty?","volume":"11","author":"Jung","year":"2022","journal-title":"J. Clin. Med."},{"key":"B13","doi-asserted-by":"publisher","first-page":"e24138","DOI":"10.1097\/MD.0000000000024138","article-title":"Retrospective study of relationship between vastus medialis volume on SPECT-CT and outcome of unilateral total knee arthroplasty","volume":"100","author":"Kim","year":"2021","journal-title":"Medicine"},{"key":"B14","doi-asserted-by":"publisher","first-page":"666","DOI":"10.1302\/2046-3758.148.BJR-2024-0216.R2","article-title":"Evaluating upper leg muscle volume the reliability of thigh circumference measurement 10 Cm above the patella","volume":"14","author":"Kono","year":"2025","journal-title":"Bone Jt. Res."},{"key":"B15","doi-asserted-by":"publisher","first-page":"1226","DOI":"10.1016\/j.clnu.2004.06.004","article-title":"Composition of the ESPEN working group. Bioelectrical impedance analysis--part I: review of principles and methods","volume":"23","author":"Kyle","year":"2004","journal-title":"Clin. Nutr."},{"key":"B16","doi-asserted-by":"publisher","first-page":"1493","DOI":"10.1007\/S11999-009-0801-2","article-title":"Reversing muscle and mobility deficits 1 to 4 years after TKA: a pilot study","volume":"467","author":"Lastayo","year":"2009","journal-title":"Clin. Orthop. Relat. Res."},{"key":"B17","doi-asserted-by":"publisher","first-page":"1142","DOI":"10.1152\/JAPPLPHYSIOL.01120.2013","article-title":"The validity of anthropometric leg muscle volume estimation across a wide spectrum: from able-bodied adults to individuals with a spinal cord injury","volume":"116","author":"Layec","year":"2014","journal-title":"J. Appl. Physiol."},{"key":"B18","doi-asserted-by":"publisher","first-page":"2764","DOI":"10.3390\/APP11062764","article-title":"Potential instability and malfunction of knee joints with vastus medialis impairment after total knee arthroplasty","volume":"11","author":"Lee","year":"2021","journal-title":"Appl. Sci."},{"key":"B19","doi-asserted-by":"publisher","first-page":"397S","DOI":"10.1093\/AJCN\/64.3.397S","article-title":"Biological indexes considered in the derivation of the bioelectrical impedance analysis","volume":"64","author":"Lukaski","year":"1996","journal-title":"Am. J. Clin. Nutr."},{"key":"B20","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1177\/193229681200600126","article-title":"Bioelectrical impedance assessment of wound healing","volume":"6","author":"Lukaski","year":"2012","journal-title":"J. Diabetes Sci. Technol."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1327","DOI":"10.1152\/jappl.1986.60.4.1327","article-title":"Validation of tetrapolar bioelectrical impedance method to assess human body composition","volume":"60","author":"Lukaski","year":"1986","journal-title":"J. Appl. Physiol."},{"key":"B22","doi-asserted-by":"publisher","first-page":"330","DOI":"10.1097\/MCO.0000000000000387","article-title":"Assessment of adult malnutrition and prognosis with bioelectrical impedance analysis: phase angle and impedance ratio","volume":"20","author":"Lukaski","year":"2017","journal-title":"Curr. Opin. Clin. Nutr. Metab. Care"},{"key":"B23","doi-asserted-by":"publisher","first-page":"809","DOI":"10.3390\/NU11040809","article-title":"Classification of hydration in clinical conditions: indirect and direct approaches using bioimpedance","volume":"11","author":"Lukaski","year":"2019","journal-title":"Nutrients"},{"key":"B24","doi-asserted-by":"publisher","first-page":"163","DOI":"10.5312\/WJO.V5.I3.163","article-title":"Anterior knee pain after a total knee arthroplasty: what can cause this pain?","volume":"5","author":"Martinus Breugem","year":"2014","journal-title":"World J. Orthop."},{"key":"B25","doi-asserted-by":"publisher","first-page":"246","DOI":"10.2519\/JOSPT.2008.2715","article-title":"Total knee arthroplasty: muscle impairments, functional limitations, and recommended rehabilitation approaches","volume":"38","author":"Meier","year":"2008","journal-title":"J. Orthop. Sports Phys. Ther."},{"key":"B26","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1519\/00139143-200932020-00007","article-title":"The long-term contribution of muscle activation and muscle size to quadriceps weakness following total knee arthroplasty - PubMed","volume":"32","author":"Meier","year":"2009","journal-title":"J. Geriatr. Phys. Ther."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1545","DOI":"10.1152\/JAPPLPHYSIOL.00611.2012","article-title":"Heterogeneous atrophy occurs within individual lower limb muscles during 60 days of bed rest","volume":"113","author":"Miokovic","year":"2012","journal-title":"J. Appl. Physiol."},{"key":"B28","doi-asserted-by":"publisher","first-page":"424","DOI":"10.2519\/JOSPT.2005.35.7.424","article-title":"Quadriceps strength and the time course of functional recovery after total knee arthroplasty","volume":"35","author":"Mizner","year":"","journal-title":"J. Orthop. Sports Phys. Ther."},{"key":"B29","doi-asserted-by":"publisher","first-page":"1047","DOI":"10.2106\/JBJS.D.01992","article-title":"Early quadriceps strength loss after total knee arthroplasty. The contributions of muscle atrophy and failure of voluntary muscle activation","volume":"87","author":"Mizner","year":"","journal-title":"J. Bone Jt. Surg. Am."},{"key":"B30","doi-asserted-by":"publisher","first-page":"e0148193","DOI":"10.1371\/JOURNAL.PONE.0148193","article-title":"Serial changes of quadriceps and hamstring muscle strength following total knee arthroplasty: a meta-analysis","volume":"11","author":"Moon","year":"2016","journal-title":"PLoS One"},{"key":"B31","doi-asserted-by":"publisher","first-page":"237","DOI":"10.1088\/0967-3334\/34\/2\/237","article-title":"Localized bioimpedance to assess muscle injury","volume":"34","author":"Nescolarde","year":"2013","journal-title":"Physiol. Meas."},{"key":"B32","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1088\/0967-3334\/36\/1\/27","article-title":"Effects of muscle injury severity on localized bioimpedance measurements","volume":"36","author":"Nescolarde","year":"2015","journal-title":"Physiol. Meas."},{"key":"B33","doi-asserted-by":"publisher","first-page":"L1","DOI":"10.1088\/1361-6579\/AA7243","article-title":"Detection of muscle gap by L-BIA in muscle injuries: clinical prognosis","volume":"38","author":"Nescolarde","year":"2017","journal-title":"Physiol. Meas."},{"key":"B34","doi-asserted-by":"publisher","first-page":"574124","DOI":"10.3389\/FPHYS.2020.574124","article-title":"Differentiation between tendinous, myotendinous and myofascial injuries by L-BIA in professional football players","volume":"11","author":"Nescolarde","year":"2020","journal-title":"Front. Physiol."},{"key":"B35","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1007\/S11154-023-09790-9","article-title":"Phase angle in localized bioimpedance measurements to assess and monitor muscle injury","volume":"24","author":"Nescolarde","year":"2023","journal-title":"Rev. Endocr. Metab. Disord."},{"key":"B36","doi-asserted-by":"publisher","first-page":"811","DOI":"10.1161\/01.cir.2.6.811","article-title":"Electrical impedance plethysmography; a physical and physiologic approach to peripheral vascular study","volume":"2","author":"Nyboer","year":"1950","journal-title":"Circulation"},{"key":"B37","doi-asserted-by":"publisher","first-page":"111930","DOI":"10.1016\/j.ejrad.2025.111930","article-title":"Degeneration of the cartilage quality is correlated with a higher intramuscular fat infiltration of the vastus medialis in older adults with pre-to-mild knee osteoarthritis","volume":"183","author":"Okada","year":"2025","journal-title":"Eur. J. Radiol."},{"key":"B38","doi-asserted-by":"publisher","first-page":"145","DOI":"10.3233\/IES-2009-0346","article-title":"Measurement of thigh muscle size using tape or ultrasound is a poor indicator of thigh muscle strength","volume":"17","author":"O\u2019Sullivan","year":"2009","journal-title":"Isokinet. Exerc Sci."},{"key":"B39","first-page":"390","article-title":"Muscle-specific changes of lower extremities in the early period after total knee arthroplasty: insight from tensiomyography","volume":"20","author":"Paravlic","year":"2020","journal-title":"J. Musculoskelet. Neuronal Interact."},{"key":"B40","doi-asserted-by":"publisher","first-page":"627","DOI":"10.1007\/S00296-019-04271-2","article-title":"Fatty infiltration in the thigh muscles in knee osteoarthritis: a systematic review and meta-analysis","volume":"39","author":"Pedroso","year":"2019","journal-title":"Rheumatol. Int."},{"key":"B41","doi-asserted-by":"publisher","first-page":"225","DOI":"10.1249\/MSS.0B013E3181EB639A","article-title":"Time course of quad strength, area and activation after knee arthroplasty and strength training","volume":"43","author":"Petterson","year":"2011","journal-title":"Med. Sci. Sports Exerc"},{"key":"B42","doi-asserted-by":"publisher","first-page":"534","DOI":"10.1038\/ki.1994.305","article-title":"A new method for monitoring body fluid variation by bioimpedance analysis: the RXc graph","volume":"46","author":"Piccoli","year":"1994","journal-title":"Kidney Int."},{"key":"B43","doi-asserted-by":"publisher","first-page":"1128","DOI":"10.1002\/MUS.21075","article-title":"Reference values for 50-kHZ electrical impedance myography","volume":"38","author":"Rutkove","year":"2008","journal-title":"Muscle Nerve"},{"key":"B44","doi-asserted-by":"publisher","first-page":"887","DOI":"10.1002\/MUS.25561","article-title":"Sensitivity distribution simulations of surface electrode configurations for electrical impedance myography","volume":"56","author":"Rutkove","year":"2017","journal-title":"Muscle Nerve"},{"key":"B45","doi-asserted-by":"publisher","first-page":"95","DOI":"10.1186\/s13054-016-1269-6","article-title":"Impact of hyperhydration on the mortality risk in critically ill patients admitted in intensive care units: comparison between bioelectrical impedance vector analysis and cumulative fluid balance recording","volume":"8","author":"Samoni","year":"2016","journal-title":"Crit. Care"},{"key":"B46","doi-asserted-by":"publisher","first-page":"010502","DOI":"10.11613\/BM.2021.010502","article-title":"Sample size, power and effect size revisited: simplified and practical approaches in pre-clinical, clinical and laboratory studies","volume":"31","author":"Serdar","year":"2021","journal-title":"Biochem. Med. Zagreb."},{"key":"B47","doi-asserted-by":"publisher","first-page":"5303","DOI":"10.1007\/S00402-022-04750-5\/FIGURES\/9","article-title":"The course of knee extensor strength after total knee arthroplasty: a systematic review with meta-analysis and -regression","volume":"143","author":"Singla","year":"2023","journal-title":"Arch. Orthop. Trauma Surg."},{"key":"B48","doi-asserted-by":"publisher","first-page":"775","DOI":"10.1016\/S0736-0266(03)00052-4","article-title":"Quadriceps strength and volitional activation before and after total knee arthroplasty for osteoarthritis","volume":"21","author":"Stevens","year":"2003","journal-title":"J. Orthop. Res."},{"key":"B49","first-page":"427","article-title":"Qualitative human body composition analysis assessed with bioelectrical impedance - PubMed","volume":"22","author":"Talluri","year":"1998","journal-title":"Coll. Antropol."},{"key":"B50","doi-asserted-by":"publisher","first-page":"647","DOI":"10.1152\/JAPPLPHYSIOL.00323.2022","article-title":"Effects of total knee arthroplasty on skeletal muscle structure and function at the cellular, organellar, and molecular levels","volume":"133","author":"Toth","year":"2022","journal-title":"J. Appl. Physiol."},{"key":"B51","doi-asserted-by":"publisher","first-page":"424","DOI":"10.1097\/MCO.0B013E328356B944","article-title":"Segmental bioelectrical impedance analysis: an update","volume":"15","author":"Ward","year":"2012","journal-title":"Curr. Opin. Clin. Nutr. Metab. Care"},{"key":"B52","doi-asserted-by":"publisher","first-page":"679","DOI":"10.1007\/S00296-019-04247-2","article-title":"Characteristics of individual thigh muscles including cross-sectional area and adipose tissue content measured by magnetic resonance imaging in knee osteoarthritis: a cross-sectional study","volume":"39","author":"Yamauchi","year":"2019","journal-title":"Rheumatol. Int."},{"key":"B53","doi-asserted-by":"publisher","first-page":"38","DOI":"10.1016\/j.rehab.2019.06.018","article-title":"Atrophy of individual thigh muscles measured by MRI in older adults with knee osteoarthritis: a cross-sectional study","volume":"63","author":"Yamauchi","year":"2020","journal-title":"Ann. Phys. Rehabil. Med."},{"key":"B54","doi-asserted-by":"publisher","first-page":"320","DOI":"10.1016\/J.CLINBIOMECH.2007.10.008","article-title":"Examining outcomes from total knee arthoplasty and the relationship between quadriceps strength and knee function over time","volume":"23","author":"Yoshida","year":"2008","journal-title":"Clin. Biomech. (Bristol, Avon)"}],"container-title":["Frontiers in Physiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2026.1745998\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T05:25:21Z","timestamp":1774329921000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fphys.2026.1745998\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,24]]},"references-count":54,"alternative-id":["10.3389\/fphys.2026.1745998"],"URL":"https:\/\/doi.org\/10.3389\/fphys.2026.1745998","relation":{},"ISSN":["1664-042X"],"issn-type":[{"value":"1664-042X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,24]]},"article-number":"1745998"}}