Ultrasound evaluation of the ulnar collateral ligament of the elbow: Which method is most reproducible?

Shoulder and Elbow Injuries in Adult Overhead Throwers: Imaging Review

Overhead throwing, particularly in baseball, subjects the shoulder and elbow to various unique injuries. Capsular contracture following repetitive external rotation shifts the humeral head posterosuperiorly, predisposing to glenohumeral internal rotation deficit (GIRD), Bennett, posterosuperior internal impingement (PSI), and superior labrum anterior-posterior (SLAP) lesions. GIRD represents loss of internal rotation at the expense of external rotation. Bennett lesion represents ossification of the posteroinferior glenohumeral ligament due to repetitive traction. PSI manifests with humeral head cysts and "kissing" tears of the posterosuperior cuff and labrum. Scapular dysfunction contributes to symptoms of PSI and predisposes to labral or rotator cuff disease. "Peel-back" or SLAP lesions occur when torsional forces detach the biceps-labral anchor from the glenoid. Finally, disorders of the anterior capsule, latissimus dorsi, teres major, and subscapularis are well recognized in overhead throwers. At the elbow, injuries typically involve the medial-sided structures. The ulnar collateral ligament (UCL) is the primary static restraint to valgus stress and can be thickened, attenuated, ossified, and/or partially or completely torn. Medial epicondylitis can occur with tendinosis, partial tear, or complete rupture of the flexor-pronator mass and can accompany UCL tears and ulnar neuropathy. Posteromedial impingement (PMI) and valgus extension overload syndrome are related entities that follow abundant valgus forces during late cocking or acceleration, and deceleration. These valgus stresses wedge the olecranon into the olecranon fossa, leading to PMI, osteophytes, and intra-articular bodies. Other osseous manifestations include olecranon stress fracture and cortical thickening of the humeral shaft. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Reliability of sonographic measurements of the ulnar collateral ligament: a multi-rater prospective study

Background

The use of sonography is a cost-effective and reliable method to evaluate upper extremity superficial tissue structural integrity and pathology. Establishing the measurement reliability of widely used diagnostic ultrasound evaluation for musculoskeletal assessment is paramount enhance accurate clinical evaluations. The objective of this study was to establish the inter-rater and intra-rater reliability of select ulnar collateral ligament (UCL) thickness measures at two distinct anatomical locations in intercollegiate baseball athletes using ultrasound imaging (USI).

Methods

This was a prospective cohort study conducted in a university research laboratory and included a total of 17 NCAA Division I baseball athletes (age 20.4 ± 1.43, height = 183.63 cm ± 6.27 cm, mass = 89.28 kg ± 8.24 kg). Two trained clinicians measured UCL mid-substance and apex thickness in the throwing extremity, prospectively, on 5 occasions at 1-month intervals during rest. Intraclass correlation coefficients (ICCs) (model 3,3), associated standard error of measurement, and 95% minimal detectable change in thickness were derived.

Results

Intrarater reliability estimates for operator 1 were 0.90-0.98 (mid-substance) and 0.91-0.99 (apex). Operator 2's values were 0.92-0.97 and 0.93-0.99, respectively. The standard error of measurement (SEM) ranged from 0.045-0.071 cm (mid-substance) and 0.023-0.067 cm (apex). The minimal detectable difference (MDD95) was 0.12-0.20 cm (mid-substance) and 0.07-0.19 cm (apex). Interrater reliability was 0.86-0.96 (mid-substance) and 0.79-0.98 (apex); most ICCs were >0.90. Measurement of UCL thickness at two locations demonstrated very good to excellent reliability with high precision. Using this protocol, two evaluators can obtain consistent UCL measurement at two positions. This finding has significant implications for the clinical evaluation of superficial tissue pathology of the same individual by two experienced practitioners.

Increased Pitch Velocity Is Associated With Throwing Arm Kinetics, Injury Risk, and Ulnar Collateral Ligament Reconstruction in Adolescent, Collegiate, and Professional Baseball Pitchers: A Qualitative Systematic Review

PURPOSE

To assess the relationship between pitch velocity and throwing arm kinetics, injury, and ulnar collateral ligament reconstruction (UCLr) among high school, collegiate, and professional baseball pitchers.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (2008-2019), and OVID/MEDLINE (2008-2019) were queried for articles that reported on pitch velocity predicting throwing arm kinetics, injury, or UCLr. The Methodological Index for Non-randomized Studies checklist was used to evaluate the quality of all included studies. Descriptive statistics with ranges were used to quantify data where appropriate.

RESULTS

A total of 24 studies examining 2,896 pitchers, with Level of Evidence II-V were included. Intergroup analysis noted pitch velocity was significantly correlated with elbow varus torque in high school (R² = 0.36), collegiate (R² = 0.29), and professional (R² = 0.076) pitchers. Elbow distraction force was positively associated with ball velocity in interpitcher analyses of high school (R² = 0.373), professional (R² = 0.175), and mixed-cohort evaluations (R² = 0.624). Intragroup analysis demonstrated a strong association between pitch velocity and elbow varus torque (R² = 0.922-0.957) and elbow distraction force (R² = 0.910) in professional pitchers. Faster ball velocity was positively associated with a history of throwing arm injury (R² = 0.194) in nonadult pitchers. In 2 studies evaluating professionals, injured pitchers had faster pitch velocity before injury compared with uninjured controls (P = .014; P = .0354). The need for UCLr was positively correlated with pitch velocity (R² = 0.036) in professional pitchers. The consequences of UCLr noted little to no decrease in pitch velocity.

CONCLUSIONS

Professional baseball pitchers with faster pitch velocity may be at the greatest risk of elbow injury and subsequent UCLr, potentially through the mechanism of increased distractive forces on the medial elbow complex. When a pitcher ultimately undergoes UCLr, decreases in pitching performance are unlikely, but may occur, which should encourage pitchers to caution against maximizing pitch velocity.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II-IV studies.

The Role of Ultrasound in the Evaluation of Elbow Medial Ulnar Collateral Ligament Injuries in Throwing Athletes

PURPOSE OF REVIEW

Although ultrasound (US) imaging is commonly used to evaluate the elbow medial ulnar collateral ligament (mUCL) in throwing athletes, significant technical heterogeneity exists in the published literature and in practice. This has resulted in variable and often ambiguous US diagnostic criteria for mUCL injury. This review summarizes the literature on sonographic evaluation of the mUCL and outlines recommendations for consistent descriptive terminology, as well as future clinical and research applications.

RECENT FINDINGS

Both acute and chronic throwing loads in overhead athletes cause the mUCL to become thicker and more lax on stress testing, and these changes tend to revert after a period of prolonged rest. Stress US (SUS) can aid in the diagnosis of mUCL tears and may help identify athletes at risk of mUCL injury. Variability exists in terminology, elbow flexion angle, amount of stress applied, and technique of stress testing. Recent studies have suggested an injured elbow stress delta (SD-change in ulnohumeral joint (UHJ) space with valgus stress) of 2.4 mm and a stress delta difference (SDD-side-side difference in SD) of 1 mm each denote abnormal UHJ laxity due to mUCL injury. US imaging is a powerful and widely accessible tool in the evaluation elbow mUCL injuries. Sonologists should consider how their US techniques compare with published methods and use caution when applying diagnostic criteria outside of those circumstances. Currently, an SD of 2.4 mm and an SDD of 1 mm provide the best diagnostic accuracy for mUCL tears requiring surgery. Finally, preliminary work suggests that shear wave elastography may be helpful in evaluating the biomechanical properties of the mUCL, but additional research is needed.

Ultrasonography: an interesting imaging method for ligament assessment during the acute phase of closed elbow injuries

PURPOSE

To evaluate whether ultrasonography can be used to explore the medial and lateral ligament structures during the acute phase of a closed elbow injury.

METHODS

A single-center, prospective study performed between December 2019 and June 2020, including patients who suffered a radial head fracture or elbow dislocation. Two radiologists did a blinded analysis using ultrasonography of visibility, injury grade, and presence of bone avulsion for the radial collateral ligament (RCL), lateral ulnar collateral ligament (LUCL), annular ligament (AL), and anterior (MCLant) and posterior bundles (MCLpost) of the medial collateral ligament. The inter-rater agreement was calculated. The ultrasonography findings were compared with the intraoperative findings in the patients who subsequently underwent surgery.

RESULTS

Forty patients were included (28 radial head fractures and 12 elbow dislocations). The inter-rater agreement was strong for all the study parameters (kappa between 0.65 and 1), except for the visibility of the LUCL (kappa 0.52) and the visibility and appearance of the MCLpost (kappa 0.54 and 0.47, respectively). The injured ligaments were thicker than their contralateral counterparts (p < 0.05). In the 10 patients who underwent surgery, the radiological-surgical correlation was 100% for the RCL and medial ligaments and 70% for the LUCL.

CONCLUSION

Ultrasonography is a reproducible examination that can be used to assess the damage to elbow ligaments during the acute phase following an injury. This examination could be incorporated into the exploration protocol for elbow injuries during the preoperative assessment and to adapt the treatment.

Elbow Torque May be Predictive of Anatomic Adaptations to the Elbow After a Season of Collegiate Pitching: A Dynamic Ultrasound Study

Purpose

To determine whether elbow torque was associated with anatomic adaptations of the medial elbow following a season of competitive pitching.

Methods

Pitchers from 3 collegiate baseball teams were recruited during the preseason for participation. Before the season, pitchers were recorded throwing 5 “game-speed” fastball pitches from a standard distance off a mound while wearing a wearable sensor baseball compression sleeve that calculates elbow torque, arm speed, arm slot, and arm rotation. Participants subsequently underwent dynamic ultrasound imaging of the medial elbow, including measurements of the ulnar collateral ligament (UCL) and ulnohumeral joint space to assess elbow laxity. Following a full season of competitive pitching, all testing was repeated, and statistical analysis comparing preseason to postseason sonographic findings was performed.

Results

Twenty-eight collegiate pitchers underwent preseason sonographic and kinematic testing. Nineteen pitchers were available for postseason testing. The average age (standard deviation) and playing experience was 19.9 (1.2) and 14.7 (1.5) years. Compared with preseason, there were significant increases in postseason UCL thickness (1.92 ± 0.09 vs 1.56 ± 0.09 mm, P < .01) and elbow laxity (1.77 ± 0.23 vs 1.15 ± 0.22 mm, P = .028) after a season of pitching. No significant changes in pitching kinematic measurements were observed between preseason and postseason testing. Preseason pitching kinematic measurements were significantly associated with increased UCL thickness (arm slot: beta estimate –0.03 ± 0.01, P = .011) and reduction in elbow laxity (elbow torque: beta estimate –0.03 ± 0.01, P = .04) after a season of pitching. Pitchers with increased body weight and arm length demonstrated reduced medial elbow torque during pitching (P < .05).

Conclusions

After a season of competitive pitching, adaptive changes of the medial elbow were demonstrated on dynamic ultrasound. However, the influence of pitching kinematic measurements on these adaptations are of small magnitude and unknown clinical significance. Although wearable sensor technology may have value in trending individual pitcher kinematics, no discrete threshold appears to predict the development of adaptive changes at the elbow.

Level of Evidence

Level II, prospective observational study.

Professional Pitchers Display Differences in UCL Morphology and Elbow Gapping During Moving Valgus Stress Testing After UCL Reconstruction

Background:

Ulnar collateral ligament (UCL) reconstruction (UCLR) of the elbow has received much attention given the rise in incidence among baseball pitchers. Stress ultrasonography has been demonstrated to be a critical evaluation tool of the UCL. No study has dynamically evaluated the ability of UCLR to restore normal kinematics.

Purpose/Hypothesis:

The purpose of this study was to compare ulnohumeral gapping during a moving valgus stress test as well as UCL thickness between professional pitchers with and without UCLR. We hypothesized that the ulnohumeral joint will display greater gapping and the UCL graft will be thicker in pitchers after UCLR compared with uninjured pitchers.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Ultrasonography was used to measure the medial ulnohumeral joint distance and the UCL thickness of 70 asymptomatic professional baseball pitchers; 6 of the participants had a history of UCLR. Images were captured of the dominant (D) and nondominant (ND) elbows at the maximal cocking position under 2 loaded conditions within the moving valgus stress test arc: (1) gravity stress and (2) 2.5 kg (5.5 lb) of valgus force using a dynamometer. Intra- and interrater reliability of the measurements was established with intraclass correlation coefficients (ICCs). Separate mixed-model analyses of variance (D side × UCL) were used to compare the D and ND elbow variables between pitchers with and without a history of UCLR.

Results:

All measurements displayed good reliability according to ICCs. Pitchers with a history of UCLR demonstrated less gapping (5.6 ± 2.9 vs 4.2 ± 1.2 mm; P = .002) and greater UCL graft thickness (0.17 ± 0.07 vs 0.11 ± 0.08 mm; P = .03) compared with the native ligament in pitchers without prior UCL injury.

Conclusion:

Our data demonstrated that the UCLR results in a thicker, stiffer construct with less medial elbow gapping than the anatomical UCL. Using ultrasound to evaluate the UCL was a reliable, efficient, and clinically feasible method to assess UCL thickness and joint gapping in players with a history of UCLR. Future studies may consider this approach to evaluate surgical techniques and graft types for UCLR.

Elbow Torque Is Reduced in Asymptomatic College Pitchers With Elbow Laxity: A Dynamic Ultrasound Study

PURPOSE

To determine the relation between medial elbow torque, as measured by wearable sensor technology, and adaptations of the medial elbow structures on dynamic ultrasound imaging in asymptomatic collegiate pitchers.

METHODS

Thirty-four pitchers from National Collegiate Athletic Association Division II universities were eligible for preseason testing. The exclusion criteria included age younger than 18 years, history of surgery, non-pitcher, or current restrictions. Pitchers were fitted with a wearable sensor sleeve that recorded elbow torque, arm slot, arm speed, and arm rotation. Pitchers threw 5 fastballs in a standardized manner off the mound at game-speed effort. They also underwent dynamic ultrasound imaging of the elbow by a musculoskeletal sonographer, with standardized valgus loading. Images were deidentified, and measurements of the ulnar collateral ligament (UCL) and ulnohumeral joint space (UHJS), to assess elbow laxity, were performed by a musculoskeletal radiologist.

RESULTS

The final analysis included 28 pitchers with an average age of 20.1 years (standard deviation, 1.3 years; range, 18-23 years) and playing experience of 15.3 years (standard deviation, 1.8 years; range, 11-19 years). The dominant UCL thickness (P < .001), loaded UHJS (P = .039), and delta UHJS (P < .001) were significantly greater than the nondominant measurements. An inverse correlation was found between loaded UHJS and medial elbow torque (r = -0.4, P < .001). Additionally, every 1-mm increase in UHJS significantly reduced medial elbow torque by 2.27 Nm (P = .032) and arm slot by 8.8° (P = .019) and increased arm rotation by 5.3° (P = .043). Pitchers with a loaded UHJS of 4.4 mm or greater and delta UHJS of 1.25 mm or greater had significantly reduced medial elbow torque (P < .001). Pitchers with a UCL thickness of 1.65 mm or greater had significantly increased medial elbow torque (47.4 Nm vs 44.8 Nm, P = .006).

CONCLUSIONS

Pitchers with increased dynamic elbow laxity were found to experience reduced medial elbow torque while pitching. Additionally, pitchers with greater UCL thickness on ultrasound were found to experience increased medial elbow torque while pitching. This study's findings suggest a relation between anatomic adaptations found on ultrasound of the pitching elbow and medial elbow torque.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Advanced Musculoskeletal Ultrasound Techniques: What Are the Applications?

OBJECTIVE. The purpose of this article is to cover technical advances in musculo-skeletal ultrasound from the viewpoint of the radiologist. CONCLUSION. Among the advances in musculoskeletal ultrasound that we highlight the use of ultrahigh-frequency transducers to visualize ever-finer anatomic detail, the expanding practical clinical applications for microvascular imaging, and the use of elastography to predict function and, possibly, healing potential.

State of the Union on Ulnar Collateral Ligament Reconstruction in 2020: Indications, Techniques, and Outcomes

PURPOSE OF REVIEW

There has been a marked increase in the number of ulnar collateral ligament reconstructions performed annually and an associated increase in the amount of recent literature published. It is paramount that surgeons remain up to date on the current literature, as modern indications and surgical techniques continue to improve clinical outcomes.

RECENT FINDINGS

Our understanding of ulnar collateral ligament (UCL) injuries, treatment indications, and surgical techniques for UCL reconstruction continues to evolve. Despite the rapidly increasing amount of published literature on the topic, a clear and concise surgical algorithm is lacking. Studies have suggested a trend towards improved clinical outcomes and decreased complications with various modifications in UCL reconstruction techniques. Current sport-specific outcome studies have reported conflicting results regarding the effect of UCL reconstruction on an athlete's performance upon returning to sport. With the rising incidence of UCL reconstruction and growing media attention, UCL injuries, reconstruction techniques, and return to sport following UCL surgery are timely topics of interest to clinicians and overhead throwing athletes. Several technique modifications have been reported, and these modifications may lead to improved outcomes and lower complication rates. Studies assessing sport-specific outcome measures will be necessary to provide a more critical and informative analysis of outcomes following UCL reconstruction.

Do anatomic changes found in the throwing arm after a season of pitching resolve with off-season rest? A dynamic ultrasound study

Hypothesis

Our hypothesis was that seasonal adaptive changes in the ulnar collateral ligament (UCL), ulnohumeral joint space (UHJS), and glenohumeral internal rotation deficit (GIRD) of the pitching extremity would subsequently resolve with off-season rest.

Methods

Eleven collegiate pitchers underwent preseason, postseason, and off-season evaluations including physical examination; dynamic ultrasound imaging of the UCL and UHJS; and the short version of the Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Ultrasound images were evaluated by 2 fellowship-trained musculoskeletal radiologists.

Results

All 11 pitchers were included in the final analysis, with an average age of 20.1 years and with 14.1 years of playing experience. After a season of pitching, we found significant increases in GIRD (P = .004) and UCL thickness (P = .033) and nonsignificant increases in both unloaded (P = .069) and loaded (P = .122) UHJS. Preseason GIRD correlated with this increase in loaded UHJS (r = 0.80, P = .003). The increase in UCL thickness was significantly greater in pitchers with GIRD greater than 10° (P < .05). After the off-season, UCL thickness returned to baseline and significant decreases were noted in both unloaded (P = .004) and loaded (P = .041) UHJS, but a progression in GIRD was found (P = .021). Pitchers with GIRD of 10° or less showed greater improvement in UHJS after the off-season (P < .05).

Conclusions

The pitching season produced adaptive changes in the throwing elbow that subsequently resolved after off-season rest. However, shoulder range-of-motion deficits were progressive and did not resolve. Ultrasound adaptations of the pitching elbow were significantly related to GIRD.

Shear-wave elastography of the ulnar collateral ligament of the elbow in healthy volunteers: a pilot study

OBJECTIVE

To estimate the intra-observer repeatability of shear wave elastography in the UCL of the elbow, and to compare shear wave velocities between dominant and non-dominant arms.

MATERIALS AND METHODS

Twenty elbows in ten healthy volunteers were evaluated [five males, five females; mean age, 31.8 ± 10.3 years]. Shear wave velocity was measured on three separate days during the span of 1 week utilizing a linear 18-MHz transducer. Elastograms were obtained until ten ROIs were drawn, not drawing more than two ROIs on any elastogram. Elastograms were considered diagnostic if any portion of the UCL was colored in and free of boundary artifacts. Median velocity and interquartile range were recorded. A result was considered reliable if the IQR/median ratio of the ten measurements was < 0.3.

RESULTS

IQR/median was < 0.3 in 88% of sessions, although in 28% of sessions fewer than 60% of elastograms were diagnostic. The ICC was 0.05 (95% CI; - 0.18-0.36; poor). Repeatability coefficient (95% limits of agreement) was 1.95 m/s (95% CI; 1.61-2.37 m/s). Mean velocity in dominant arms was 5.14 ± 0.53 m/s and 5.24 ± 0.39 m/s in non-dominant (p = 0.558).

CONCLUSIONS

Mean shear wave velocity was similar between dominant and non-dominant arms. Although repeatability was poor as assessed by ICC, the repeatability coefficient may be a more useful indicator of clinical utility once shear wave velocities in diseased ligaments are explored. Future studies should therefore evaluate velocities in diseased ligaments and develop techniques to improve elastogram quality.