Qualitative and Quantitative Analyses of the Dynamic and Static Stabilizers of the Medial Elbow: An Anatomic Study

2017 ◽  
Vol 46 (3) ◽  
pp. 687-694 ◽  
Author(s):  
Salvatore J. Frangiamore ◽  
Gilbert Moatshe ◽  
Bradley M. Kruckeberg ◽  
David M. Civitarese ◽  
Kyle J. Muckenhirn ◽  
...  

Background: The anterior bundle of the medial ulnar collateral ligament (UCL) and the forearm flexors provide primary static and dynamic stability to valgus stress of the elbow in overhead-throwing athletes. Quantitative anatomic relationships between the dynamic and static stabilizers have not been described. Purpose: To perform qualitative and quantitative anatomic evaluations of the medial elbow-UCL complex with specific attention to pertinent osseous and soft tissue landmarks. Study Design: Descriptive laboratory study. Methods: Ten nonpaired, fresh-frozen human cadaveric elbows (mean age, 54.1 years [range, 42-64 years]; all male) were utilized for this study. Quantitative analysis was performed with a 3-dimensional coordinate measuring device to quantify the location of pertinent bony landmarks and tendon and ligament footprints on the humerus, ulna, and radius. Results: The anterior bundle of the UCL attached 8.5 mm (95% CI, 6.9-10.0) distal and 7.8 mm (95% CI, 6.6-9.1) lateral to the medial epicondyle, 1.5 mm (95% CI, 0.5-2.5) distal to the sublime tubercle, and 7.3 mm (95% CI, 6.1-8.5) distal to the joint line on the ulna along the ulnar ridge. The flexor digitorum superficialis (FDS) ulnar tendinous insertion was closely related and interposed within the anterior bundle of the UCL, overlapping with 45.6% (95% CI, 38.1-53.6) of the length of the anterior bundle of the UCL. The flexor carpi ulnaris (FCU) attached 1.9 mm (95% CI, 0.8-2.9) posterior and 1.3 mm (95% CI, 0.6-3.2) proximal to the sublime tubercle and overlapped with 20.9% (95% CI, 7.2-34.5) of the area of the distal footprint of the anterior bundle of the UCL. Conclusion: The anterior bundle of the UCL had consistent attachment points relative to the medial epicondyle and sublime tubercle. The ulnar limb of the FDS and FCU tendons demonstrated consistent insertions onto the ulnar attachment of the anterior bundle of the UCL. These anatomic relationships are important to consider when evaluating distal UCL tears both operatively and nonoperatively. Excessive stripping of the sublime tubercle should be avoided during UCL reconstruction to prevent violation of these tendinous attachments. Clinical Relevance: The findings of this study enhance the understanding of valgus restraint in throwing athletes and provide insight into the difference in nonoperative outcomes between proximal and distal tears of the UCL.

2018 ◽  
Vol 6 (3) ◽  
pp. 232596711876275 ◽  
Author(s):  
Christopher L. Camp ◽  
Hamidreza Jahandar ◽  
Alec M. Sinatro ◽  
Carl W. Imhauser ◽  
David W. Altchek ◽  
...  

Background: A more detailed assessment of the anatomy of the entire medial ulnar collateral ligament complex (MUCLC) is desired as the rate of medial elbow reconstruction surgery continues to rise. Purpose: To quantify the anatomy of the MUCLC, including the anterior bundle (AB), posterior bundle (PB), and transverse ligament (TL). Study Design: Descriptive laboratory study. Methods: Ten unpaired, fresh-frozen cadaveric elbows underwent 3-dimensional (3D) digitization and computed tomography with 3D reconstruction. Ligament footprint areas and geometries, distances to key bony landmarks, and isometry were determined. A surgeon digitized the visual center of each footprint, and this location was compared with the geometric centroid calculated from the outline of the digitized footprint. Results: The mean surface area of the AB was 324.2 mm2, with an origin footprint of 32.3 mm2 and an elongated insertional footprint of 187.6 mm2 (length, 29.7 mm). The mean area of the PB was 116.6 mm2 (origin, 25.9 mm2; insertion, 15.8 mm2), and the mean surface area of the TL was 134.5 mm2 (origin, 21.2 mm2; insertion, 16.7 mm2). The geometric centroids of all footprints could be predicted within 0.8 to 1.3 mm, with the exception of the AB insertion centroid, which was 7.6 mm distal to the perceived center at the apex of the sublime tubercle. While the PB remained relatively isometric from 0° to 90° of flexion ( P = .606), the AB lengthened by 2.2 mm ( P < .001). Conclusion: Contrary to several historical reports, the insertional footprint of the AB was larger, elongated, and tapered. The TL demonstrated a previously unrecognized expansive soft tissue insertion directly onto the AB, and additional analysis of the biomechanical contribution of this structure is needed. Clinical Relevance: These findings may serve as a foundation for future study of the MUCLC and help refine current surgical reconstruction techniques.


2019 ◽  
Vol 7 (2) ◽  
pp. 232596711882529 ◽  
Author(s):  
Brandon J. Erickson ◽  
Michael Fu ◽  
Kate Meyers ◽  
Christopher L. Camp ◽  
David W. Altchek ◽  
...  

Background: The medial ulnar collateral ligament (UCL) insertion of the elbow has been shown to extend distally beyond the sublime tubercle. The contribution to valgus stability of the distal aspect of the footprint is unknown. Purpose/Hypothesis: The purpose of this study was to determine the contribution of each part of the UCL footprint to the elbow valgus stability provided by the UCL. It was hypothesized that the distal two-thirds of the ulnar UCL footprint would not contribute significantly to valgus stability provided by the UCL. Study Design: Descriptive laboratory study. Methods: Fifteen cadaveric arms were dissected to the capsuloligamentous elbow structures and potted. A servohydraulic load frame was used to place 5 N·m of valgus stress on the intact elbow at 30°, 60°, 90°, and 120° of flexion. The UCL insertional footprint was measured and divided into thirds (proximal, middle, and distal). One-third of the UCL footprint was elevated off the bone (leaving the ligament in continuity), and the elbow was retested at the same degrees of flexion. This was repeated until the entire UCL footprint on the ulna was sectioned. Each elbow was randomized for how the UCL would be sectioned (sectioning the proximal, then middle, and then distal third or sectioning the distal, then middle, and then proximal third). Ulnohumeral joint gapping (millimeters) was recorded with a 3-dimensional motion capture system using physical and virtual markers. Two-group comparisons were made between each sectioned status versus the intact condition for each flexion angle. Results: When the UCL was sectioned from distal to proximal, none of the ligaments failed prior to complete sectioning. When the UCL was sectioned from proximal to distal, 3 of the 6 ligaments failed after sectioning of the proximal third, while 2 more failed after the proximal and middle thirds were sectioned. Of the specimens with the distal third of the ligament sectioned first, no significant differences were found between intact, distal third cut, and distal plus middle thirds cut at all flexion angles. Conclusion: The middle and distal thirds of the insertional footprint of the UCL on the ulna did not significantly contribute to gap resistance at 5 N·m of valgus load. The proximal third of the footprint is the primary resistor of valgus load. Clinical Relevance: This cadaveric biomechanical study demonstrated that the middle and distal thirds of the native UCL insertion onto the ulna did not significantly contribute to valgus resistance at the elbow. When a UCL reconstruction is performed, the proximal third of the UCL insertion may be the most clinically important portion of the ligament to reconstruct.


Author(s):  
Harold A. Cook ◽  
Sam Akhavan ◽  
Patrick J. DeMeo ◽  
Mark Carl Miller

The ulnar collateral ligament (UCL) of the elbow originates on the medial epicondyle of the humerus and inserts on the sublime tubercle of the proximal ulna. This ligament is classically composed of three distinct structures: the anterior bundle, the posterior bundle, and the transverse bundle. Of these three, the anterior bundle has been shown to be the primary stabilizer to valgus load between 20° and 120° of flexion [1]. Injuries to the anterior bundle of the UCL are commonly seen in baseball pitchers, where the valgus load on the elbow during the throwing motion approaches the failure load of the ligament [2].


2020 ◽  
Author(s):  
Shota Hoshika ◽  
Akimoto Nimura ◽  
Norimasa Takahashi ◽  
Hiroyuki Sugaya ◽  
Keiichi Akita

Abstract 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.


2017 ◽  
Vol 46 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Bradley M. Kruckeberg ◽  
Jorge Chahla ◽  
Gilbert Moatshe ◽  
Mark E. Cinque ◽  
Kyle J. Muckenhirn ◽  
...  

Background: The qualitative and quantitative anatomy of the medial patellar stabilizers has been reported; however, a quantitative analysis of the anatomic and radiographic attachments of all 4 ligaments relative to anatomic and osseous landmarks, as well as to one another, has yet to be performed. Purpose: To perform a qualitative and quantitative anatomic and radiographic evaluation of the medial patellofemoral ligament (MPFL), medial patellotibial ligament (MPTL), medial patellomeniscal ligament (MPML), and medial quadriceps tendon femoral ligament (MQTFL) attachment sites, with attention to their relationship to pertinent osseous and soft tissue landmarks. Study Design: Descriptive laboratory study. Methods: Ten nonpaired fresh-frozen human cadaveric knees were dissected, and the MPFL, MPTL, MPML, and MQTFL were identified. A coordinate measuring device quantified the attachment areas of each structure and its relationship to pertinent bony landmarks. Radiographic analysis was performed through ligament attachment sites and relevant anatomic structures to assess their locations relative to pertinent bony landmarks. Results: Four separate medial patellar ligaments were identified in all specimens. The center of the MPFL attachments was 14.3 mm proximal and 2.1 mm posterior to the medial epicondyle and 8.3 mm distal and 2.7 mm anterior to the adductor tubercle on the femur and 8.9 mm distal and 19.9 mm medial to the superior pole on the patella. The MQTFL had a mean insertion length of 29.3 mm on the medial aspect of the distal quadriceps tendon. The MPTL and MPML shared a common patellar insertion and were 9.1 mm proximal and 15.4 mm medial to the inferior pole. The MPTL attachment inserted on a newly identified bony ridge, which was located 5.0 mm distal to the joint line. The orientation angles of the MPTL and MPML with respect to the patellar tendon were 8.3° and 22.7°, respectively. Conclusion: The most important findings of this study were the correlative anatomy of 4 distinct medial patellar ligaments (MPFL, MPTL, MPML, MQTFL), as well as the identification of a bony ridge on the medial proximal tibia that consistently served as the attachment site for the MPTL. The quantitative and radiographic measurements, while comparable with current literature, detailed the meniscal insertion of the MPML and defined a patellar insertion of the MPTL and the MPML as a single attachment. The data allow for reproducible landmarks to be established from previously known bony and soft tissue structures. Clinical Relevance: The findings of this study provide the anatomic foundation needed for an improved understanding of the role of medial-sided patellar restraints. This will help to further refine injury patterns and/or soft tissue deficiencies that result in lateral patellar instability, which can then be addressed with an anatomic-based reconstruction or repair technique and potentially lead to improved outcomes.


Author(s):  
Amin M. Motlagh ◽  
Mark Carl Miller

The multi-bundle structure of the medial ulnar collateral ligament (mUCL) has been documented [1] and it is known that the anterior bundle of the mUCL is the primary restraint to valgus stress of the elbow [2–5]. It has also been documented that the anterior band of this bundle becomes taut in extension whereas the posterior band becomes taut in flexion [1]. The mUCL is frequently injured in the throwing athlete due to over use or extreme valgus load. In order to reconstruct the ligament, surgical repair may be required. It has been experimentally observed in our lab and in other labs that the UCL wraps around the medial epicondyle. One of the parameters to ensure achievement of a successful surgical reconstruction may be the re-establishment of the natural wrapping behavior of UCL around the epicondyle. Previous studies [6] also suggest that soft-tissue wrapping constraints have substantial impact on joint stability. This study begins to characterize the wrapping of the two bands in the anterior bundle of UCL in terms of the location along the ligament’s length and flexion angle to establish native behavior.


2020 ◽  
Author(s):  
Shota Hoshika ◽  
Akimoto Nimura ◽  
Norimasa Takahashi ◽  
Hiroyuki Sugaya ◽  
Keiichi Akita

Abstract 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 ). Conclusion s : 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.


2021 ◽  
Vol 9 (1) ◽  
pp. 232596712097366
Author(s):  
Zhen-Zhen Dai ◽  
Lin Sha ◽  
Zi-Ming Zhang ◽  
Zhen-Peng Liang ◽  
Hao Li ◽  
...  

Background: The tibial tubercle–trochlear groove (TT-TG) distance was originally described for computed tomography (CT), but it has been measured on magnetic resonance imaging (MRI) in patients with patellar instability (PI). Whether the TT-TG measured on CT versus MRI can be considered equivalent in skeletally immature children remains unclear. Purpose: To investigate in skeletally immature patients (1) the effects of CT versus MRI imaging modality and cartilage versus bony landmarks on consistency of TT-TG measurement, (2) the difference between CT and MRI measurements of the TT-TG, and (3) the difference in TT-TG between patients with and without PI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We retrospectively identified 24 skeletally immature patients with PI and 24 patients with other knee disorders or injury but without PI. The bony and cartilaginous TT-TG distances on CT and MRI were measured by 2 researchers, and related clinical data were collected. The interrater, interperiod (bony vs cartilaginous), and intermethod (CT vs MRI) reliabilities of TT-TG measurement were assessed with intraclass correlation coefficients. Results: The 48 study patients (19 boys, 29 girls) had a mean age of 11.3 years (range, 7-14 years). TT-TG measurements had excellent interrater reliability and good or excellent interperiod reliability but fair or poor intermethod reliability. TT-TG distance was greater on CT versus MRI (mean difference, 4.07 mm; 95% CI, 2.6-5.5 mm), and cartilaginous distance was greater than bony distance (mean difference, 2.3 mm; 95% CI, 0.79-3.8 mm). The TT-TG measured on CT was found to increase with the femoral width. Patients in the PI group had increased TT-TG distance compared with those in the control group, regardless of landmarks or modality used ( P > .05 for all). Conclusion: For skeletally immature patients, the TT-TG distance could be evaluated on MRI, regardless of whether cartilage or bony landmarks were used. Its value could not be interchanged with CT according to our results; however, further research on this topic is needed.


Author(s):  
D. Jackson ◽  
P. Ireland ◽  
B. Cheong

Progress in the computing power available for CFD predictions now means that full geometry, 3 dimensional predictions are now routinely used in internal cooling system design. This paper reports recent work at Rolls-Royce which has compared the flow and htc predictions in a modern HP turbine cooling system to experiments. The triple pass cooling system includes film cooling vents and inclined ribs. The high resolution heat transfer experiments show that different cooling performance features are predicted with different levels of fidelity by the CFD. The research also revealed the sensitivity of the prediction to accurate modelling of the film cooling hole discharge coefficients and a detailed comparison of the authors’ computer predictions to data available in the literature is reported. Mixed bulk temperature is frequently used in the determination of heat transfer coefficient from experimental data. The current CFD data is used to compare the mixed bulk temperature to the duct centreline temperature. The latter is measured experimentally and the effect of the difference between mixed bulk and centreline temperature is considered in detail.


Hand Surgery ◽  
2010 ◽  
Vol 15 (03) ◽  
pp. 157-159 ◽  
Author(s):  
Piyapong Tiyaworanan ◽  
Surut Jianmongkol ◽  
Tala Thammaroj

The incidence and the anatomical location of the arcade of Struthers as related to the arm length were studied in 62 arms of adult fresh-frozen cadavers. The distance between the greater tuberosity and the lateral epicondyle was designated as the arm length. The arcades of Struthers were identified in 85.4%. The mean arm length was 27.85 ± 1.3 cm. The mean of the distance between proximal border of the arcade of Struthers and the medial humeral epicondyle was 8.24 ± 2.06 cm. The mean ratio between the distance from the proximal border of the arcade to the tip of the medial epicondyle and arm length was 0.29 ± 0.07. We concluded that the anatomical location of the arcade as related to the arm length was 29% proximally, from the tip of the medial epicondyle. This report of the anatomical location of the arcade of Struthers related to the arm length can be useful to identify this structure in the arms which have differences in arm length during the surgical exploration and anterior transposition of the ulnar nerve procedures.


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