Martine T Dolan1, Michael J Patetta1, Sonia Pradhan1, Dmitriy Peresada1, Danil Rybalko1, Aimee Bobko1, Jason L Koh2,3, Lewis Shi3, Benjamin A Goldberg4, Farid Amirouche1,2. 1. Department of Orthopaedic Surgery, University of Illinois, 835 S. Wolcott Avenue, E270 MSS MC 844, Chicago, IL, 60612, USA. 2. Department of Orthopaedic Surgery, Orthopaedic and Spine Institute, Northshore University HealthSystem an Affiliate of University of Chicago Pritzker School of Medicine, 2650 Ridge Avenue, Suite 2505, Walgreen Building, Evanston, IL, 60201, USA. 3. Department of Orthopaedics, Shoulder and Elbow Surgery, MC3079, University of Chicago, 5841 S. Maryland Avenue, Chicago, IL, 60637, USA. 4. Department of Orthopaedic Surgery, University of Illinois, 835 S. Wolcott Avenue, E270 MSS MC 844, Chicago, IL, 60612, USA. orthodoc@uic.edu.
Abstract
PURPOSE: The rotator cuff (RC) muscles contribute to dynamic stability and rotational actions of the glenohumeral joint. Moment arm can be used to demonstrate the potential work a muscle contributes to a musculoskeletal joint rotation. This study aimed to understand the moment arm contributions of the RC muscles and explore changes following a complete supraspinatus tear treated with either superior capsular reconstruction (SCR) or reverse total shoulder arthroplasty (rTSA). METHODS: Five fresh-frozen cadaveric specimens were prepared and mounted in an apparatus where each intact RC muscle was held in tension with a line of action toward its origin on the scapula. Mean moment arms for each muscle were determined experimentally based on Optotrak data collected during cadaveric shoulder arm abduction. RESULTS: Using ANOVA testing, our analysis demonstrated significant differences (p < 0.001) in infraspinatus and teres minor moment arms after rTSA compared to the intact shoulder model. After SCR, significant differences (p < 0.001) were seen in teres minor, with these differences being statistically similar to the changes seen in teres minor after rTSA. Subscapularis showed no significant difference in moment arm values between the models (p = 0.148). CONCLUSION: Our results illustrate that mean moment arms were preserved in the RC muscles after complete supraspinatus tear. This study also shows evidence that subscapularis function may be maintained after SCR or rTSA. After SCR, infraspinatus may maintain similar abduction ability compared to the anatomical shoulder, while teres minor ability may increase. Infraspinatus may have decreased abduction ability after rTSA while teres minor may have increased ability.
PURPOSE: The rotator cuff (RC) muscles contribute to dynamic stability and rotational actions of the glenohumeral joint. Moment arm can be used to demonstrate the potential work a muscle contributes to a musculoskeletal joint rotation. This study aimed to understand the moment arm contributions of the RC muscles and explore changes following a complete supraspinatus tear treated with either superior capsular reconstruction (SCR) or reverse total shoulder arthroplasty (rTSA). METHODS: Five fresh-frozen cadaveric specimens were prepared and mounted in an apparatus where each intact RC muscle was held in tension with a line of action toward its origin on the scapula. Mean moment arms for each muscle were determined experimentally based on Optotrak data collected during cadaveric shoulder arm abduction. RESULTS: Using ANOVA testing, our analysis demonstrated significant differences (p < 0.001) in infraspinatus and teres minor moment arms after rTSA compared to the intact shoulder model. After SCR, significant differences (p < 0.001) were seen in teres minor, with these differences being statistically similar to the changes seen in teres minor after rTSA. Subscapularis showed no significant difference in moment arm values between the models (p = 0.148). CONCLUSION: Our results illustrate that mean moment arms were preserved in the RC muscles after complete supraspinatus tear. This study also shows evidence that subscapularis function may be maintained after SCR or rTSA. After SCR, infraspinatus may maintain similar abduction ability compared to the anatomical shoulder, while teres minor ability may increase. Infraspinatus may have decreased abduction ability after rTSA while teres minor may have increased ability.
Entities:
Keywords:
Biomechanics shoulder; Moment arms; Reverse total shoulder arthroplasty; Rotator cuff repair; Rotator cuff tear; Superior capsular reconstruction
Authors: Matthew A Hamilton; Phong Diep; Chris Roche; Pierre Henri Flurin; Thomas W Wright; Joseph D Zuckerman; Howard Routman Journal: J Orthop Res Date: 2015-02-12 Impact factor: 3.494
Authors: Samuel R Ward; Eric R Hentzen; Laura H Smallwood; Robert K Eastlack; Katherine A Burns; Donald C Fithian; Jan Friden; Richard L Lieber Journal: Clin Orthop Relat Res Date: 2006-07 Impact factor: 4.176
Authors: Joseph E Langenderfer; Cameron Patthanacharoenphon; James E Carpenter; Richard E Hughes Journal: J Orthop Res Date: 2006-08 Impact factor: 3.494
Authors: Teruhisa Mihata; Michelle H McGarry; Joseph M Pirolo; Mitsuo Kinoshita; Thay Q Lee Journal: Am J Sports Med Date: 2012-08-10 Impact factor: 6.202
Authors: David C Ackland; Wen Wu; Richard Thomas; Minoo Patel; Richard Page; Morgan Sangeux; Martin Richardson Journal: J Orthop Res Date: 2019-06-18 Impact factor: 3.494