Medial elbow anatomy: A paradigm shift for UCL injury prevention and management

Hoshika, Shota; Nimura, Akimoto; Yamaguchi, Reiko; Nasu, Hisayo; Yamaguchi, Kumiko; Sugaya, Hiroyuki; Akita, Keiichi

doi:10.1002/ca.23322

Cited by 29 publications

(38 citation statements)

References 44 publications

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“…Previous studies have reported that the UCL of the dominant elbow in professional baseball pitchers was thicker than that of the non-dominant elbow and its thickness was associated with increased laxity against valgus stress [20,25]. Recently, Hoshika et al [26] identified that the anterior bundle of the UCL could be interpreted as part of the tendinous complex, which consisted of the tendinous septum (TS) and the FDS muscle. In other words, UCL thickness could be interpreted as the FDS muscle thickness.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, the FDS muscle of the index finger is located in the superficial layer and that of the middle finger in the deep layer [27]. Hoshika et al [26] also reported that the tendinous complex might be a pathway of the muscular power of the FPMs to the humeroulnar joint. Taking these anatomical concepts into consideration, the FDS muscles of the index and middle fingers may connect with the TS; thus, these fingers could provide more dynamic stability against valgus stress than that of the ring finger via the TS.…”

Section: Discussionmentioning

confidence: 99%

“…Our study provides clinically relevant information that can be used in the development of a program to prevent UCL injury. Recently, there has been a focus on hand muscle training to prevent throwing injuries as well as to improve performance in generating ball velocity [14,26,28]. However, Thrower's Ten, which has a long history of use by overhead throwing athletes, incorporates multiple strengthening exercises for the shoulder, elbow, and wrist but fails to address the finger flexors [15].…”

Section: Discussionmentioning

confidence: 99%

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Valgus stability is enhanced by flexor digitorum superficialis muscle contraction of the index and middle fingers

et al. 2020

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Background: Flexor digitorum superficialis (FDS) muscle provides dynamic stabilization and medial elbow support for ulnar collateral ligament (UCL). The FDS contraction significantly affects the medial joint distance (MJD) through grip contraction. However, it remains unclear whether FDS activity alone contributes to medial elbow stability, or together with the activation of the flexor digitorum profundus during grip contraction, and which finger's FDS is the main contributor to elbow stability. We investigated the resistive effects of isolated FDS contraction in individual fingers against valgus stress in the elbow joint using stress ultrasonography (US). Methods: We investigated 17 healthy males (mean age, 27 ± 5 years). Valgus stress US was performed using the Telos device, with the elbow at 30°flexion. MJD was measured for each arm during 3 separate conditions: at rest (unloaded), under valgus load (50 N) (loaded), and under valgus load with FDS contracted in individual fingers (loaded-contracted). Results: MJD was significantly longer when loaded (5.4 ± 0.4 mm) than unloaded (4.1 ± 0.2 mm, P = 0.007) or loadedcontracted (4.6 ± 0.3 mm, P = 0.003) for each finger. When loaded-contracted, MJD differed statistically between the index and ring fingers (P = 0.03) and between the middle and ring fingers (P = 0.04). However, the difference between the index and middle fingers was not statistically significant (P = 0.08). Conclusions: Individual FDS contraction, particularly of the index and middle fingers, contributes most to stabilization against valgus stress. Thus, injury care programs should incorporate FDS exercises of these fingers.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Valgus stability is enhanced by flexor digitorum superficialis muscle contraction of the index and middle fingers

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Discussionmentioning

confidence: 99%

“…Our study provides clinically relevant information that can be used in the development of a program to prevent UCL injury. Recently, there has been a focus on hand muscle training to prevent throwing injuries as well as to improve performance in generating ball velocity [14,26,28]. However, the Thrower's Ten, which has a long history of use by overhead throwing athletes, incorporates multiple strengthening exercises for the shoulder, elbow, and wrist, but fails to address the finger flexors [15].…”

Section: Discussionmentioning

confidence: 99%

Valgus Stability is Enhanced by Flexor Digitorum Superficialis Muscle Contraction of the Index and Middle Fingers

Hoshika

Nimura

Takahashi

et al. 2020

Preprint

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Background: Flexor digitorum superficialis (FDS) muscle provides dynamic stabilization and medial elbow support for ulnar collateral ligament (UCL). The FDS contraction significantly affects the medial joint distance (MJD) through grip contraction. However, it remains unclear whether FDS activity alone contributes to medial elbow stability, or together with the activation of the flexor digitorum profundus during grip contraction, and which finger’s FDS is the main contributor to elbow stability. We investigated the resistive effects of isolated FDS contraction in individual fingers against valgus stress in the elbow joint using stress ultrasonography (US).Methods: We investigated 17 healthy males (mean age, 27 ± 5 years). Valgus stress US was performed using the Telos device, with the elbow at 30° flexion. MJD was measured for each arm during 3 separate conditions: at rest (unloaded), under valgus load (50 N) (loaded), and under valgus load with FDS contracted in individual fingers (loaded-contracted). Results: MJD was significantly longer when loaded (5.4 ± 0.4 mm) than unloaded (4.1 ± 0.2 mm, P = .007) or loaded-contracted (4.6 ± 0.3 mm, P = .003) for each finger. When loaded-contracted, MJD differed statistically between the index and ring fingers (P = .03) and between the middle and ring fingers (P = .04). However, the difference between the index and middle fingers was not statistically significant (P = .08). Conclusions: Individual FDS contraction, particularly of the index and middle fingers contributes most to stabilization against valgus stress. Thus, injury care programs should incorporate FDS exercises of these fingers.

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Comparative histomorphological analysis of elbow ligaments and capsule

et al. 2022

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This study aimed to compare the histomorphology of the elbow capsule and its ligaments to gain a better understanding of the clinically relevant biomechanical stabilization. Eleven human elbows were dissected including the joint capsule with its anterior (AJC) and posterior (PJC) parts, the annular ligament (AL), the radial collateral ligament (RCL) and the ulnar collateral ligament with its anterior (AUCL), posterior (PUCL) and transverse (TUCL) parts. Hematoxylin–Eosin and Elastica van Gieson as conventional histology stainings were applied to determine collagenous and elastic fiber arrangements in transmission and polarization light microscopy. The radial collateral ligament and the anterior part of the ulnar collateral ligament showed significantly more densely packed parallel fiber arrangement than the anterior joint capsule, the posterior joint capsule, and the posterior part of the ulnar collateral ligament (p < 0.02, respectively). The PUCL had significantly more mixed tight and loose parallel arrangements than the PJC, the annular ligament, the RCL, the AUCL and the transverse part of the ulnar collateral ligamentp < 0.02, respectively), while the PJC showed significantly more interlaced mixed tight and loose fiber arrangement than the AL, the RCL and the AUCL (p < 0.003, respectively). The AJC had a significantly higher amount of elastic fibers as compared to the AL, the RCL, the AUCL and the TUCL in fascicular regions (p < 0.04, respectively), while the AUCL had significantly lesser elastic fibers than the AJC and the PJC (p < 0.004, respectively). The densely packed parallel fiber arrangement and few elastic fibers of the AUCL, RCL, and AL indicate a strong biomechanically stabilizing function. The fiber arrangement of the PUCL and the TUCL with few elastic fibers support the medial elbow stabilization. Crimping and elastic fibers provide the viscoelasticity of the joint capsule.

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Medial elbow anatomy: A paradigm shift for UCL injury prevention and management

Cited by 29 publications

References 44 publications

Valgus stability is enhanced by flexor digitorum superficialis muscle contraction of the index and middle fingers

Valgus stability is enhanced by flexor digitorum superficialis muscle contraction of the index and middle fingers

Valgus Stability is Enhanced by Flexor Digitorum Superficialis Muscle Contraction of the Index and Middle Fingers

Comparative histomorphological analysis of elbow ligaments and capsule

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