Minced muscle autografting improves bone healing but not muscle function in a porcine composite injury model

Todd O McKinley; Roman N Natoli; Naveena B Janakiram; Stuart J Warden; Robyn K Fuchs; Zachary Gunderson; Nichlaus Diggins; Seungyup Sun; George Kolettis; Stephen M Goldman; Christopher L Dearth; Stephen Mendenhall; Caio Staut; Melissa A Kacena; Benjamin T Corona

doi:10.1002/jor.25551

Minced muscle autografting improves bone healing but not muscle function in a porcine composite injury model

J Orthop Res. 2023 Sep;41(9):1890-1901. doi: 10.1002/jor.25551. Epub 2023 Mar 26.

Authors

Todd O McKinley¹, Roman N Natoli¹, Naveena B Janakiram^{2

3}, Stuart J Warden⁴, Robyn K Fuchs⁴, Zachary Gunderson⁵, Nichlaus Diggins⁵, Seungyup Sun⁵, George Kolettis¹, Stephen M Goldman^{2

3}, Christopher L Dearth^{2

3}, Stephen Mendenhall⁶, Caio Staut¹, Melissa A Kacena¹, Benjamin T Corona⁷

Affiliations

¹ Department of Orthopaedic Surgery, Indiana University School of Medicine, IU Health Methodist Hospital, Indianapolis, Indiana, USA.
² Department of Surgery, Uniformed Services University of the Health Sciences and Walter Reed National Military Medical Center, Bethesda, Maryland, USA.
³ DoD-VA Extremity Trauma & Amputation Center of Excellence, Bethesda, Maryland, USA.
⁴ Department of Physical Therapy, Indiana University School of Health and Human Sciences, Indiana University, Indianapolis, Indiana, USA.
⁵ Indiana University School of Medicine, Indianapolis, Indiana, USA.
⁶ Department of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana, USA.
⁷ Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA.

PMID: 36924069
DOI: 10.1002/jor.25551

Abstract

Composite tissue injuries (CTIs) in extremities include segmental bone defects (SBDs) and volumetric muscle loss. The objective of this study was to determine if skeletal muscle autografting with minced muscle grafts (MMGs) could improve healing in an SBD and improve muscle function in a porcine CTI model that includes an SBD and adjacent volumetric muscle loss injury. Adult Yucatan Minipigs were stratified into three groups including specimens with an isolated SBD, an SBD with volumetric muscle loss (CTI), and an SBD with volumetric muscle loss treated with MMG (CTI + MMG). Bone healing was quantified with serial x-rays and postmortem computed tomography scanning. Muscle function was quantified with a custom in vivo force transducer. Muscle tissue content was determined by biochemical analyses and histology. Anterior cortex-modified Radiographic Union Score for Tibia fractures (mRUSTs) decreased from 2.7 to 1.9 (p = 0.003) in CTI versus SBD animals. MMG improved anterior mRUST scores to 2.5 in CTI + MMG specimens (p = 0.030 compared to CTI specimens) and overall mRUST scores increased from 9.4 in CTI specimens to 11.1 in CTI + MMG specimens (p = 0.049). Residual strength deficits at euthanasia were 42% in SBD (p < 0.001), 44% in CTI (p < 0.001), and 48% in CTI + MMG (p < 0.001) compared to preoperative values. There were no differences in strength deficits between the three groups. Biochemical and histologic analyses demonstrated scattered differences between the three groups compared to contralateral muscle. MMG improved bone healing. However, the primary cause of muscle dysfunction and biochemical changes was the presence of an SBD. Clinical significance: Early mitigation of SBDs may be necessary to prevent muscle damage and weakness in patients sustaining composite extremity trauma.

Keywords: functional muscle testing; minced muscle grafting; open tibia fracture; segmental bone defect; volumetric muscle loss.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Animals
Fracture Healing
Muscle Strength
Muscle, Skeletal* / physiology
Swine
Swine, Miniature
Tibial Fractures* / pathology
Transplantation, Autologous