Muscle Morphology and Function Following a Transfemoral Amputation: A Systematic Review

BACKGROUND: Restoring function and mobility after transfemoral amputation (TFA) is crucial for prosthesis use and heavily relies on muscle morphology and function in the residual limb. After amputation, the loss of distal muscle insertions alters morphology and might impair (muscle) functioning. OBJECTIVE: To provide a comprehensive and critically appraised overview of the existing evidence on muscle morphology and function of the residual limb following TFA. METHODOLOGY: A literature search was conducted in PubMed, Embase, and CINAHL, including articles published up to September 15, 2025. Language was restricted to English, Dutch and German. Articles were eligible if they included individuals with a TFA and objectively measured outcomes related to muscle morphology and/or function. Methodological quality was assessed using the Joanna Briggs Institute critical appraisal checklist and the review followed the PRISMA guidelines. RESULTS: Out of 1832 identified articles, 24 met the inclusion criteria. Eight articles reported outcomes related to muscle morphology while sixteen articles reported outcomes on muscle function. All articles assessing muscle volume and cross-sectional area reported reductions in most residual-limb muscle groups compared to the intact limb. Across articles assessing muscle function, the residual limb generated reduced hip flexion, extension, and abduction torques compared to the intact and/or control limb, while adduction torque diminished only at lower isokinetic speeds. The magnitude of alterations varied greatly between articles. No article investigated both muscle morphology and function. Therefore, the interrelationship between these outcomes could not be determined. CONCLUSION: The literature shows that muscle morphology and function are significantly altered in the residual limb following TFA, although reported effects vary across articles and muscle groups. Study heterogeneity limited exploration of factors that could account for this variation. This needs future study. Future research also should combine assessments of muscle morphology and function to better understand these variations. Layman's Abstract People who undergo an above‑knee amputation rely heavily on the strength and health of the remaining muscles in their upper leg to walk and use a prosthesis. After the amputation, some muscles lose their normal attachment to the bone, which can change how these muscles work. To better understand these changes, we reviewed studies that measured muscle structure or muscle strength in people with an above‑knee amputation. A search of three databases (PubMed, Embase, and CINAHL) was conducted. Out of 1,832 articles, 24 studies met the criteria to be included. Overall, these studies showed that the remaining leg muscles are often weaker and smaller than those in the intact limb or in people without an amputation. Many studies found reduced strength when lifting the leg forward, backward, or sideways. Most studies also reported smaller muscle size and more fatty tissue in the muscles of the residual limb. However, the amount of change differed widely between studies, and the reasons for these differences are still unclear. None of the studies measured muscle strength and muscle structure together in the same individuals, making it difficult to understand how these two aspects are related. Overall, this review shows that an above‑knee amputation affects how strong the remaining muscles are and how they are built, but the causes of the differences seen from person to person remain unknown. Future research should measure muscle strength and muscle structure together and look at personal and surgery‑related factors to better understand how these muscles adapt after amputation. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/47289/35029 How To Cite: Kroes C.M, Schelhaas R, Dekker R, Geertzen J.H.B, van Kammen K, Houdijk H. Muscle morphology and function following a transfemoral amputation: A systematic review. Can Prosthet Orthot J. 2026;9(1):9. https://doi.org/10.33137/cpoj.v9i1.47289 Corresponding Author: Claudia M. Kroes, PhD Affiliations: 1) Department of Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; 2) Department of Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.E-Mail: c.m.kroes@umcg.nlORCID ID: https://orcid.org/0009-0001-3403-5899