Dynamic Stress Ultrasound Assessment of Professional Baseball Players' Elbows After Ulnar Collateral Ligament Reconstruction.

BACKGROUND: There is a paucity of data analyzing dynamic stress ultrasound (SUS) findings in elite pitchers who have undergone ulnar collateral ligament (UCL) reconstruction (UCLR) and returned to sport. PURPOSE: To identify longitudinal, perioperative changes in the elbows of professional baseball pitchers who have undergone UCLR and to compare these findings with a matched cohort of healthy pitchers. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This study used prospectively collected data from dynamic elbow SUS analyses of professional baseball pitchers within a single Major League Baseball organization. Pitchers were divided into 2 cohorts: a UCLR cohort and healthy cohort. The UCLR cohort eligibility included availability of (1) SUS from preseason of injury/UCLR and (2) SUS from ≥2 years after surgery. These players were 1:1 matched to players with no history of upper extremity injury to form the healthy cohort. Ligament thickness and ulnohumeral joint space at rest and under stress were directly measured. Joint laxity was calculated by subtracting joint space at rest from joint space under stress. The term "relative" was used to describe calculated differences where nondominant measurements were subtracted from dominant-side measurements. RESULTS: Eight pitchers were included in the UCLR group and matched to 8 healthy pitchers (mean age at initial SUS examination, 19.6 years). At a minimum follow-up of 2 years, there were no significant differences between groups in terms of relative or dominant arm rest space, stress space, or laxity. Longitudinally (final measurements - baseline measurements), the mean relative ulnohumeral rest space decreased in the UCLR group and increased in the healthy group (-0.36 mm vs +0.50 mm; P = .032). The finding of increased UCL thickness in the UCLR group was expected, as UCL grafts are typically thicker than native ligaments. CONCLUSION: Ulnhohumeral joint stability was achieved after UCLR as indicated by similar rest space, stress space, and joint laxity in dominant arms compared with a matched healthy cohort. A significant decrease in relative rest space after UCLR may represent the achievement of stability in surgery patients. Alternatively, the increase in ulnohumeral rest space seen in the healthy cohort may represent adaptive changes from pitching at a professional level.

Association Between Draft Order and Stress Sonography of the Ulnar Collateral Ligament of the Elbow in Professional Baseball Pitchers: An 18-Year Study.

BACKGROUND: The Major League Baseball (MLB) draft is a common route for players to enter professional baseball in the United States. Players taken in earlier rounds are typically higher-performing players. When looking at pitchers specifically, higher performance at the amateur level may be associated with an increased frequency of adaptive change in the throwing elbow. PURPOSE: To determine whether pitchers taken in earlier rounds of the MLB draft have a greater frequency or extent of pathological change in the elbow, as measured by dynamic stress ultrasound. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Dynamic stress ultrasounds (SUSs) were performed over 18 years on the dominant and nondominant arms of 651 professional pitchers. The 383 drafted players were grouped according to the round in which they were drafted (rounds 1-5, 6-10, 11-20, 21+). Groups were compared with respect to "relative" ulnar collateral ligament (UCL) thickness (dominant-nondominant), relative ulnohumeral joint laxity (joint space distance under stress minus joint space at rest), and the presence of pathology (calcifications, tears, hypoechoic foci, osteophytes). In addition, a subgroup analysis was done to compare the progression of SUS findings over 3 years in players for which data were available. RESULTS: Draft round groups did not differ by age, number of previous spring training, or handedness. Comparing baseline measurements, there was no significant relationship between draft round and relative UCL thickness (P = .932), relative laxity (P = .996), or presence of pathology detectable on SUS (P = .642). However, increased relative UCL thickness was significantly associated with the presence of pathology on SUS (odds ratio, 1.45; 95% CI, 1.26-1.69; P < .001). Longitudinally, there was no significant relationship between draft round and 3-year progression of relative laxity, relative UCL thickness, or clinical progression of pathology. CONCLUSION: Higher-performing pitchers are drafted earlier in the MLB draft. This may be attributable to peak pitch velocity, in-game performance, visibility gained during player showcases, or any number of other sport-specific variables. However, despite this, there was no significant relationship between draft round and adaptive changes to the elbow or specific properties of the UCL on stress ultrasound.

The influence of a single 30-pitch session on elbow laxity in adolescent and collegiate baseball pitchers.

BACKGROUND: Ulnar collateral ligament (UCL) injuries are a source of significant injury among baseball players, and are increasingly evaluated under ultrasound. The purpose of this study is to determine the effect of a single session of pitching upon UCL thickness and laxity via a cross sectional, controlled ultrasonographic study. We hypothesize that a single session of pitching will cause the ulnar collateral ligament to thicken and become more lax. METHODS: This was a cross sectional comparative study of collegiate and high school pitchers. Pitchers underwent an ultrasonographic assessment of the UCL before and after a thirty-pitch bullpen warm-up. Laxity was measured as the change in the distance between the ulna and the trochlea with and without a 5-pound weight held in hand with the elbow at 30° of flexion. Pre- and post-throwing UCL thickness and medial laxity were statistically compared with paired tests. RESULTS: Our study included 15 pitchers, 8 collegiate and 7 high school level athletes. All played baseball at least 6 days a week, and nearly all played for at least 10 months a year. Pitchers reported a peak velocity of 89 ± 6 (77 to 98) miles per hour. In the prior season, these pitchers pitched 56 ± 33 (10 to 120) games, throwing 62 ± 34 (25-140) pitches per game on average. After throwing, there was significantly less UCL laxity (P = .013). Post-throwing laxity was significantly positively correlated with both peak pitch velocity (P = .009) and an average number of pitches thrown per game (P = .10). CONCLUSION: Throwing 30 pitches significantly decreases medial elbow laxity with stress, possibly due to flexor-pronator activation. Post-throwing medial laxity is correlated with both peak pitch velocity and average number of pitches thrown per game. Future studies should be conducted to determine the number of throws at which laxity begins to increase, as this may provide a workload management guideline for injury prevention.

Thumb Metacarpophalangeal Joint Kinematics and Elongation of the Ulnar Collateral Ligament.

PURPOSE: The purpose of the study was to determine if the sphericity of the thumb metacarpophalangeal (MCP) joint influences the joint's rotational axis (RA) and elongation patterns of the ulnar collateral ligament (UCL). METHODS: Ulnar collateral ligament origins and attachments of 28 fresh-frozen cadaveric thumbs were marked with a radiopaque marker. Lateral radiographs were obtained in neutral and 20°, 40°, and 60° of flexion. The dorsal and palmar joint gap and the length of four different UCL portions were digitally measured in all flexion states. The RA was determined by the intersection of the midshaft axis of the proximal phalanx in neutral and flexion states. Sphericity of the MCP joint was assessed using morphometric parameters. Joints were grouped as round or flat. Differences in all measured parameters between groups were analyzed. RESULTS: During flexion, the dorsal joint gap increased by 322% in flat joints and 163% in round joints. The palmar joint gap decreased to 45% in flat joints and to 87% in round joints. The RA was at 29% of metacarpal height and 96% of metacarpal length in flat joints and at 40% of height and 86% of length in round joints. Maximum UCL elongation (111%) was noted at 40° flexion in the dorsal proper UCL in flat joints and at 60° flexion in the accessory UCL (117%) in round joints. CONCLUSIONS: In flat MCP joints, the RA is more dorsal and distal in the metacarpal head compared to round joints, resulting in a hinged flexion motion. Elongation of the UCL is highest at end flexion in round joints and highest at midflexion in flat joints. CLINICAL RELEVANCE: The different kinematics of flat and round MCP joints may contribute to the understanding of the pathophysiology of UCL ruptures. The propensity of this injury and the position in which they occur may be affected by the MCP joint morphology.

MRI spectrum of injuries to the thumb metacarpophalangeal joint ulnar collateral ligament with a proposed expanded classification of injuries in American football players.

Injuries to the ulnar collateral ligament of the thumb metacarpophalangeal joint are of both historic and modern interest for athletes and non-athletes alike. The thumb metacarpophalangeal joint requires stability in both flexion and extension utilizing a combination of static and dynamic stabilizers. This article reviews the magnetic resonance imaging categorization of thumb ulnar collateral ligament injuries and proposes two additional injury patterns seen in high-level and professional athletes who play American football. In addition to the direct magnetic resonance imaging findings in collateral ligament tears, secondary findings of rotation and subluxation can be seen at the thumb metacarpophalangeal joint due to the altered physiologic forces on the joint. Internal brace augmentation via suture tape of a traditional ulnar collateral ligament repair is a novel surgical technique that provides protection during initial healing and the ensuing remodeling phase following repair or reconstruction, resulting in a faster return to play.

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.

Repetitive pitching decreases the elbow valgus stability provided by the flexor-pronator mass: the effects of repetitive pitching on elbow valgus stability.

BACKGROUND: Baseball pitching induces a large elbow valgus load, stressing the ulnar collateral ligament (UCL). Flexor-pronator mass (FPM) contraction contributes to valgus stability; however, repetitive baseball pitching may weaken the FPM contractile function. The present study investigated the effects of repetitive baseball pitching on the medial valgus stability measured using ultrasonography. We hypothesized that repetitive pitching would decrease elbow valgus stability. METHODS: This was a controlled laboratory study. Fifteen young male baseball players at the collegiate level (age: 23.0 ± 1.4 years) were enrolled. The medial elbow joint space was measured using ultrasonography (B-mode, 12-MHz linear array transducer) in the following three conditions: at rest (unloaded), under 3 kg valgus load (loaded), and under valgus load with maximal grip contraction to activate FPM (loaded-contracted). All measurements were performed before and after the pitching tasks, which comprised five sets of 20 pitches. Two-way repeated-measures analysis of variance was applied to determine changes in the medial elbow joint space. The post hoc test with Bonferroni adjustment was applied to assess the changes within the time and condition. RESULTS: The medial elbow joint space was significantly greater under the loaded than the unloaded and loaded-contracted conditions both before and after pitching (P < .001). In the loaded-contracted condition, the medial elbow joint space significantly increased after repetitive baseball pitching (P < .001). CONCLUSIONS: The results of the present study indicated that repetitive baseball pitching reduced the elbow valgus stability. This reduction could be attributed to the decreased FPM contractile function. Insufficient contraction may increase the tensile load on the UCL with pitching. FPM contraction plays a role in narrowing the medial elbow joint space; however, repetitive baseball pitching reduced the elbow valgus stability. It has been suggested that sufficient rest and recovery of the FPM function are required to reduce the UCL injury risk.

What are the indications for medial ulnar collateral ligament surgery in baseball players? An MRI case-based study.

BACKGROUND: Ulnar collateral ligament (UCL) tears are common in baseball players. When nonoperative management fails; reconstruction or repair may be necessary to restore physical function. There is no clear consensus regarding the indications for surgery based on magnetic resonance imaging (MRI) tear characteristics or the indications for selecting repair over reconstruction. The purpose of this study was to define the indications for UCL surgery based on MRI and to elucidate indications for UCL repair vs. reconstruction. METHODS: Twenty-six orthopedic surgeons who treat baseball players were surveyed. Forty-five MRIs were reviewed: 15 without UCL tears, 15 with intraoperatively confirmed partial-thickness tears, and 15 with full-thickness tears. Factors investigated included ligament characteristics (periligamentous or osseous edema, ligament hypertrophy, calcification, partial or full-thickness tearing) and location (proximal, midsubstance, or distal). Surgeons were given a clinical scenario and asked whether 1) surgery was indicated and 2) whether repair or reconstruction was recommended. Odds ratios (OR) and 95% confidence intervals (95% CI) helped identify significant predictors for both queries. RESULTS: The odds of recommending surgical treatment compared to nonoperative treatment were 2.4× more likely for a proximal partial-thickness tear, 3.2× for distal partial-thickness tear, 5.1× for distal full-thickness tear, and 7.0× for proximal full-thickness tear (P < .001). Significant indications for repair included distal partial (OR = 1.6, 95% CI 1.0, 2.1, P < .001) and full-thickness tears (OR = 1.7, 95% CI 1.1, 2.3, P < .001). Repair was 3× less likely recommended for midsubstance full-thickness tears (OR = 3.0, 95% CI -5.0, -1.0, P = .004). Ultrasound stress testing was requested in 78% of partial tears. CONCLUSIONS: Among surgeons surveyed, the highest odds for recommending operative treatment were proximal full-thickness tears, then distal full-thickness, distal partial-thickness, and proximal partial-thickness tears. Repair was most appropriate for partial and full-thickness distal tears, but relatively contraindicated for complete midsubstance UCL tears. Ultrasound stress testing was frequently requested for partial tears. Given the lack of consensus among surgeons, future prospective registries are necessary to determine whether these factors associate with clinical outcomes.

The lateral ulnar collateral ligament: Anatomical and structural study for clinical application in the diagnosis and treatment of elbow lateral ligament injuries.

The lateral ulnar collateral ligament (LUCL) is considered one of the main stabilizers of the elbow. However, its anatomical description is not well established. Imaging techniques do not always have agreed upon parameters for the study of this ligament. Therefore, herein, we studied the macro and microanatomy of the LUCL to establish its morphological and morphometric characteristics more precisely. Fifty-five fresh-frozen human elbows underwent dissection of the lateral collateral ligament. Morphological characteristics were studied in detail. Ultrasound (US) and magnetic resonance (MR) were done before dissection. Two specimens were selected for PGP 9.5 S immunohistochemistry. Ten additional elbows were analyzed by E12 sheet plastination. LUCL was identified in all specimens and clearly defined by E12 semi-thin sections. It fused with the common extensor tendon and the radial ligament. The total length of the LUCL was 48.50 mm at 90°, 46.76 mm at maximum flexion and 44.10 mm at complete extension. Three morphological insertion variants were identified. Both US and MR identified the LUCL in all cases. It was hypoechoic in the middle and distal third in 85%. The LUCL was hypointense on MR in 95%. Free nerve endings were present on histology. The LUCL is closely related to the anular ligament. It is stretched during flexion and supination. US and MR can reliably identify its fibers. Anatomical data are relevant to the surgeon who repairs the ligaments of the elbow. Also, to the radiologist and pain physician who interpret imaging and treat patients with pain syndromes of the elbow.

Thumb Metacarpophalangeal Joint Ulnar Collateral Ligament Injuries: Management and Biomechanical Evaluation.

First described in 1955 as "gamekeeper's thumb," injuries to the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal joint are common and can cause pain and instability, especially during key pinch and grasp. Although primarily diagnosed on physical examination, stress radiographs, ultrasonography, and magnetic resonance imaging can be used to diagnose UCL injuries and distinguish partial from complete tears. If complete rupture occurs, the adductor aponeurosis can become interposed between the retracted UCL stump and its insertion on the proximal phalanx, known as a "Stener lesion." When instability persists after a trial of nonsurgical management or in the setting of complete rupture, there are various methods of repair or reconstruction. Biomechanically, there are no treatments of repair or reconstruction using native tissues that provide equivalent strength to the preinjured ligament. Recently, suture tape augmentation has been used for the repair or reconstruction with excellent short-term results and earlier return to function, although there is a paucity of literature on longer term outcomes. The various methods of surgical treatment yield excellent outcomes with a low incidence of complications.

Sonographic morphological and qualitative deficits in the elbow ulnar collateral ligament and ulnohumeral joint in throwing arms of asymptomatic collegiate baseball pitchers.

OBJECTIVE: The ulnar collateral ligament (UCL) supports the medial elbow against valgus torque and is commonly injured in baseball pitchers. Changes in UCL morphology and pathology occur with long-term pitching, with more severe findings at higher competition levels. We examined the bilateral differences and the relationship between UCL morphology, pathology, and ulnohumeral joint laxity in asymptomatic collegiate pitchers using ultrasound. MATERIALS AND METHODS: Division I college pitchers (n = 41) underwent ultrasound scans of their bilateral medial elbows, both at rest and in a valgus-stressed position. The presence of enthesopathy, calcifications, and degeneration was assessed qualitatively. UCL thickness and ulnohumeral joint gap were measured with online calipers. The bilateral differences were analyzed using paired t-tests and chi-square analysis, and the relationships between thickness, gapping, and degenerative changes were analyzed using regression analyses. RESULTS: The throwing arm demonstrated greater distal UCL thickness (mean difference (MD) = 0.2 mm (95%CI = 0.1-0.3), p < 0.01), resting and stressed gap (MD = 0.3 mm (95%CI = 0.0-0.7), p = 0.04; MD = 0.4 (95%CI = 0.0-0.9), p = 0.02), and greater prevalence of degeneration and enthesopathy (p = 0.03) compared bilaterally. Enthesopathy and calcifications predicted increased distal UCL thickness (p = 0.04; p = 0.02). Degenerative scores predicted increased stressed-resting ulnohumeral joint gap (p < 0.01). CONCLUSION: In the throwing arms of collegiate pitchers, ultrasound demonstrated UCL thickening, enthesopathy/intra-ligamentous calcification, and greater laxity of the ulnohumeral joint relative to the non-throwing arm. Degeneration of the UCL, not thickness, was related to greater elbow joint gapping. This study demonstrates the utility of ultrasound for examining sonographic characteristics of the UCL in a sample of college pitchers.

Change in humeral anchor position significantly affects isometry in ulnar collateral ligament repair: a 3-dimensional computer modeling study.

BACKGROUND: Medial ulnar collateral ligament (UCL) repair utilization is increasing in recent years, bolstered by shorter rehabilitation and satisfactory clinical outcomes. Although previous literature has illustrated the importance of tunnel position on restoring graft isometry in reconstruction, there remains a paucity of literature guiding anchor placement in UCL repair. The purpose of this study is to design a 3-dimensional (3D) elbow model to understand the effect of anchor location on UCL repair isometry. METHODS: A 3D computer model of an elbow joint was created using computed tomographic and magnetic resonance imaging MRI scans from a single patient. The humeral and ulnar attachments of the UCL were plotted using 3 methodologies: (1) geometric cloud mapping and (2) quantitative measurements from the anatomic studies by Camp et al and (3) Frangiamore et al. A 3.5-mm-diameter clockface was placed on each attachment site, which allowed for simulation of 12 distinct 1.75-mm deviations in anchor position. The 3 models were ranged through 0°-120° at 10° increments, and the 3D distances were measured between the ligament centroids. The humeral and ulnar anchors were sequentially repositioned around the clockfaces, and construct lengths were again measured to evaluate changes in isometry. A paired Student t test was performed to determine if there was a significant difference in isometry between the humeral and ulnar anchor deviations. RESULTS: Using method 1, the UCL repair length at 90° of elbow flexion was 26.8 mm. This construct underwent 13.6 mm of total excursion for a 46.4% change in length throughout its arc of motion. Method 2 produced a 19.3-mm construct that underwent 0.8 mm of excursion for a 3.9% length change throughout the arc. Method 3 produced a 24.5-mm construct that underwent 2.3 mm of excursion for a 9.4% length change. Identifying ligament footprints using the quantitative anatomic measurements from Camp et al and Frangiamore et al improved construct isometry through 120° of flexion (length changes of 3.9% and 9.4%, respectively) when compared to using the geometric cloud technique alone (46.4% length change). Humeral anchor deviations produced a significant increase in repair construct excursion compared with ulnar anchor deviations (P < .001). CONCLUSION: When performing UCL repair, small deviations in humeral anchor position may significantly influence ligament repair isometry. Using quantitative anatomic data may help identify anchor positions with improved repair isometry. Particularly when addressing detachments of the humeral footprint, surgeons should be critical of the humeral anchor position in order to restore native anatomy and optimal biomechanics.

Adolescent Baseball Pitchers With Ulnar Collateral Ligament Tears Exhibit a High Proportion of Partial Tears.

BACKGROUND: Ulnar collateral ligament (UCL) tears in the throwing elbow are classified according to grade and location using magnetic resonance arthrography (MRA). However, the frequency of each tear type and the association to age, competition level, and radiographic findings in adolescent baseball pitchers are unknown. PURPOSES: The primary purpose of this study was to use MRA to characterize the severity, location, and UCL tear type in adolescent pitchers. The second aim was to describe the relationship between the UCL tear type and age, competition level, and plain radiographic findings. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Records of adolescent pitchers with a UCL tear treated by the senior author between 2007 and 2016 were retrospectively reviewed. MRA scans were reviewed and tears were classified according to the Joyner-Andrews classification. Low-grade partial tears are classified as type I, high-grade partial tears as type II, complete full-thickness tears as type III, and tear pathology in >1 region in the UCL as type IV. Each type of tear also has a location designated at the midsubstance, ulna (U), or humerus (H). Patient characteristics, competition level, and associated plain radiographic abnormalities were recorded. Univariate analyses were performed to examine the relationships between tear types and age, competition level, and plain radiographic findings. RESULTS: A total of 200 adolescent pitchers (mean ± SD age, 17.2 ± 1.5 years) with MRA scans were reviewed. Type II-H (n = 62), type II-U (n = 51), and type III-U (n = 28) were the most common tear types observed. Type II tears comprised 64.5% of adolescent UCL tears, with type II-H being the most common. Plain radiographs were abnormal in 32% of patients, with calcifications (10.5%) and olecranon osteophytes (12.5%) being the most common findings. There were no significant relationships between tear type and age (P = .25), competition level (P = .23), or radiographic abnormalities (P = .75). CONCLUSION: Humeral-sided high-grade partial tears were the most common tear type in adolescent pitchers. There was no relationship between UCL tear type and age competition level, and plain radiographic abnormalities.

Elbow Ulnar Collateral Ligament Injuries in Overhead Athletes: An Infographic Summary.

Ulnar collateral ligament (UCL) injuries of the elbow are common in throwing athletes. Given that the UCL's primary function is to provide valgus stability during the deceleration phase of throwing, injury to the UCL will render throwing difficult to nearly impossible.15 Injuries will occur more so in the sports of baseball, softball, and javlineers participating in track and field.5,10,14 Data has indicated that valgus torque reaches 64 N-m and proximal forces as high as 1000 N to prevent elbow distraction. Further, angular velocity across elbow may reach 1900-2480 degrees/second.6,8 Imaging modalities that have the greatest accuracy for diagnosis include magnetic resonance imaging (MRI), MRI-arthrogram, and stress ultrasonography.2,3,11,12 Treatment of UCL injury depends on multiple factors. These include if the injury is a partial tear or complete tear and the location (distal versus proximal) of the partial tear.7 Further, complete tears, as well as partial distal tears, are more likely to undergo surgical intervention.1,13 Treatment decision-making is primarily dependent on following factors: location, severity, if the patient is a throwing athlete, and if the patient is in his or her last year of his/her throwing career due to the length of the rehabilitation process if surgery is pursued.15 Return-to-play success rates when treated conservatively vary from anywhere from 42% to 100%. Conservative treatment includes rest, rehabilitation, platelet-rich plasma injections, and a throwing program.4 Surgical treatment has evolved significantly with various reconstructive techniques and (when indicated) surgical repair with internal bracing. Return-to-play rates are high, ranging from 80% to 95% with low complication rates, but rehabilitation for reconstruction can range from 12-18 months or longer. Therefore, patients must be made aware of the commitment to the rehabilitation process if electing to undergo surgical reconstruction.9.

Lateral Ulnar Collateral Ligament of the Elbow Joint: Reconsideration of Anatomy in Terms of Connection with Surrounding Fibrous Structures.

BACKGROUND: To improve the clinical results of lateral ulnar collateral ligament (LUCL) reconstruction of the elbow joint, better understanding of the anatomy of the aponeuroses and joint capsule could be relevant. This study considers the previously described anatomy of the LUCL in relation to the related aponeuroses and joint capsule rather than as a discrete ligament. We hypothesized that the deep aponeuroses of the superficial extensor muscles and supinator form a relevant portion of the joint capsule previously defined as the LUCL. METHODS: Twenty-four elbows (12 right) from 21 embalmed cadavers (age at the time of death, 54 to 99 years) were included in the study. Twenty elbows were studied macroscopically and 4, histologically. The joint capsule was detached from the bones, and local thickness was quantitatively analyzed using micro-computed tomography (micro-CT). RESULTS: The supinator aponeurosis and joint capsule intermingled to form a thick membrane (mean and standard deviation, 4.8 ± 1.2 mm), which we termed "the capsulo-aponeurotic membrane." It was thicker than the anterior (1.3 ± 0.4 mm) and posterior (2.5 ± 0.9 mm) parts of the capsule of the humeroradial joint (p < 0.001). The capsulo-aponeurotic membrane had a wide attachment on the distal part of the extensor digitorum communis and extensor digiti minimi (EDC/EDM) origin of the humerus, the lateral part of the coronoid process, and the posterior part of the radial notch of the ulna. The humeral attachment had a fibrocartilaginous structure. The deep aponeuroses of the EDC and extensor carpi ulnaris (ECU) were connected to the capsulo-aponeurotic membrane. CONCLUSIONS: The capsulo-aponeurotic membrane was composed of the supinator aponeurosis and joint capsule and was attached to the lateral epicondyle of the humerus, radial side of the coronoid process, and posterior part of the radial notch on the ulna. The entire structure appeared identical to the commonly defined lateral collateral ligament. The most posterior part was connected to the EDC and ECU aponeuroses, which is commonly labeled the LUCL but does not exist as a discrete ligament. CLINICAL RELEVANCE: Consideration of the accurate anatomy of the extensive attachment of the capsulo-aponeurotic membrane could provide useful clues for improvement in techniques of LUCL reconstruction and lateral epicondylitis pathology.

Does proximal versus distal injury location of the medial ulnar collateral ligament of the elbow differentially impact elbow stability? An ultrasound-guided and robot-assisted biomechanical study.

BACKGROUND: The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury. METHODS: Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases. RESULTS: Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11° ± 2°) than the distal release (8° ± 2°) between flexion angles of 30° and 70° (P < .0001 at 30°, P < .0001 at 40°, P = .001 at 50°, P = .005 at 60°, and P = .020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P = .051 at 80°, P = .131 at 90°, P = .245 at 100°, P = .400 at 110°, and P = .532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P = .032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion. CONCLUSIONS: US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL.

Magnetic Resonance Imaging Findings After Elbow Dislocation: A Descriptive Study.

BACKGROUND: The elbow is one of the most commonly dislocated joints, and dislocation is usually accompanied with an assortment of soft tissue injuries. The purpose of this study was to retrospectively analyze and describe the patterns of ligamentous, tendinous, and muscular injuries in patients with an acute elbow dislocation and subsequent magnetic resonance image (MRI) evaluation. METHODS: From 2008 to 2020, 235 patients clinically diagnosed with an elbow dislocation were seen in the department, of which only 19 underwent an MRI of the affected elbow. Twelve patients met inclusion criteria, and MRIs were evaluated by both a radiologist and an upper extremity orthopedic surgeon. Magnetic resonance images were assessed for injury to the ulnar collateral ligament (UCL); radial collateral ligament (RCL); lateral ulnar collateral ligament (LUCL); common flexor and extensor tendons; biceps, brachialis, and triceps tendons; fracture; and joint effusion. RESULTS: Magnetic resonance imaging findings included the following: UCL was injured in 11 of 12 patients; RCL was injured in 9 of 12 patients; LUCL was injured in 9 of 12 patients; common flexor tendon was injured in 11 of 12 patients; and common extensor tendon was injured in 9 of 12 elbows. The biceps, brachialis, and triceps tendons showed injury in 1 of 12, 2 of 12, and 2 of 12 elbows, respectively. Four elbows had at least 1 fracture present, whereas 8 demonstrated an effusion. CONCLUSIONS: In this series, injuries to the UCL and common flexor tendon were most common. Although ligamentous injuries are exceedingly common in elbow dislocations, large studies of MRI findings prove difficult due to MRI costs.

Routine diagnostic arthroscopy with elbow ulnar collateral ligament reconstruction does not reduce the need for future valgus extension overload-related surgeries: a systematic review and meta-analysis.

BACKGROUND: Valgus extension overload syndrome (VEOS) most commonly affects overhead athletes and consists of a constellation of conditions involving the medial, posterior, and lateral elbow, with the most widely discussed being ulnar collateral ligament (UCL) injuries. Many athletes with UCL tears also have findings consistent with other VEOS conditions, though these are not consistently symptomatic. Given the high rate of concomitant pathology, many authors have recommended performing arthroscopy at the time of UCL reconstruction (UCLR) to diagnose and address concomitant VEOS pathology; however, it is not known if this practice actually leads to a reduction in subsequent surgeries for VEOS conditions following index UCLR. The purpose of this systematic review and meta-analysis was to determine if performing routine diagnostic arthroscopy (RDA) in patients undergoing UCLR was associated with a lower incidence of future VEOS-related surgery. METHODS: This study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with the primary outcome of interest being the likelihood of needing future surgery to address VEOS conditions with or without RDA at the time of index UCLR. The proportion and incidence rate of subsequent VEOS-related surgeries following UCLR with and without RDA were compared in mixed effects models. RESULTS: There were 25 eligible studies from an initial 1335 systematically identified articles, with results for 2118 UCLR cases. Among these, there were a total of 94 reported VEOS-related surgeries. The proportion of subsequent VEOS-related surgeries was lower when UCLR was performed with RDA (0.40%, 95% CI 0.00%-3.51%) than without (1.16%, 95% CI 0.03%-3.25%), but the difference was not significant (P = .584). The incidence rate of VEOS-related surgeries was 0.16 (95% CI 0.00-0.95) per 100 person-years with RDA and 0.14 (95% CI 0.00-0.55) per 100 person-years without RDA (P = .942). CONCLUSION: RDA preceding UCLR does not significantly reduce the proportion or rate of subsequent surgery for other VEOS conditions. There has been a decrease in RDA utilization with UCLR over time for athletes with torn/incompetent UCLs but otherwise no known symptomatic VEOS conditions, and this trend appears to be justified based on these findings.

Elbow valgus stability of the transverse bundle of the ulnar collateral ligament.

BACKGROUND: The purpose of this study was to clarify elbow valgus stability of the transverse bundle (TB). We hypothesized that the transverse bundle is involved in elbow valgus stability. METHODS: Twelve elbows of six Japanese Thiel-embalmed cadavers were evaluated. The skin, subcutaneous tissue and origin of forearm flexors were removed from about 5 cm proximal to the elbow to about 5 cm distal to the elbow, and the ulnar collateral ligament was dissected (intact state). The cut state was defined as the state when the TB was cut in the middle. The joint space of the humeroulnar joint (JS) was measured in the intact state and then in the cut state. With the elbow flexed to 30°, elbow valgus stress was gradually increased to 30, 60 N using the Telos Stress Device, and the JS was measured by ultrasonography under each load condition. Paired t-testing was performed to compare the JS between the intact and cut states under each load. RESULTS: No significant difference in JS was identified between the intact and cut state at start limb position. The JS was significantly higher in the cut state than in the intact state at both 30 N and 60 N. CONCLUSION: The findings from this study suggested that the TB may be involved in elbow valgus stability.

Return to Sport After Nonoperative Management of Medial Ulnar Collateral Ligament Injuries About the Elbow in Non-throwing Athletes.

There is a paucity of literature published on management of acute medial ulnar collateral ligament injuries in the non-throwing athlete and when these athletes may expect to safely return to sport. Non-overhead throwing athletes that sustained medial ulnar collateral ligament (MUCL) injuries treated conservatively with brace immobilization and therapy can successfully return to sport in a relatively short duration. A radiographic query of Magnetic Resonance Images (MRIs) was performed to identify patients sustaining elbow MUCL injury. Only those participating as intercollegiate athletes were included. Medical charts and documents were reviewed to determine time away from sport and rehabilitation protocol. A total of 17 patient-athletes were identified as having sustained MUCL injuries that met inclusion criteria. There was a 100% return to sport rate, averaging 5 weeks from date of injury. Non-overhead throwing athletes competing at the intercollegiate level who sustained acute MUCL injury were effectively treated nonoperatively. (Journal of Surgical Orthopaedic Advances 30(3):136-139, 2021).