The Utility of Stress Ultrasound in Identifying Risk Factors for Elbow Ulnar Collateral Ligament Tear: A Longitudinal Study of 203 Professional Baseball Players.

BACKGROUND: Injuries to the medial ulnar collateral ligament (UCL) are common among baseball pitchers due to repetitive stress on the soft tissue stabilizers of the elbow during pitching. Dynamic stress ultrasound (SUS) can be used to evaluate the UCL and ulnohumeral joint to identify anatomic risk factors of those who will require UCL reconstruction (UCLR). PURPOSE: To determine whether any adaptive or morphological changes detectable on SUS can predict injury to the UCL in professional baseball pitchers. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 203 professional baseball pitchers who underwent SUS at preseason training sessions over the course of 18 years were categorized into 1 of 2 groups: those without a history of shoulder, arm, elbow, or forearm surgery or injuries (healthy cohort; n = 184) and those who underwent UCLR the same season as SUS (UCLR cohort; n = 19). Ligament thickness, joint spacing, and laxity were compared. An additional matched cohort analysis was conducted using 10 players from each group to detect differences in the progression of UCL and ulnohumeral joint measures in the year before injury. RESULTS: The UCLR cohort, when compared with the healthy cohort, had higher relative (ie, nondominant-side measurements subtracted from dominant-side measurements) resting ulnohumeral joint space (median, 0.50 vs 0.20 mm, respectively; P = .006) and higher rates of hypoechoic foci (57.9% vs 30.4%, respectively; P = .030). Players of both groups had similar dominant UCL thickness (P = .161), ulnohumeral joint space at rest (P = .321), space under stress (P = .498), and laxity (P = .796). Groups did not differ in terms of relative UCL thickness, ulnohumeral joint space under stress, or relative laxity. In the year before UCL injury, the UCLR cohort, compared with the matched healthy cohort, had a greater increase in mean dominant UCL thickness (0.94 vs -0.60 mm, respectively; P = .038) and a greater increase in relative median UCL thickness (1.35 vs -0.35 mm, respectively; P = .045). Players in the healthy cohort were statistically older than those in the UCLR cohort (23 vs 22 years, respectively; P = .004). No differences in ulnohumeral stress spacing or laxity were detected. CONCLUSION: SUS of players who underwent UCLR demonstrated a progressive increase in UCL thickness over 1 year, higher rates of hypoechoic foci, and increased ulnohumeral rest space compared with SUS of uninjured players.

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.

Characterizing focal muscle signal on MRI in flexor-pronator muscles' status post ulnar collateral ligament reconstruction.

OBJECTIVE: Focal high signal is commonly seen about the flexor pronator mass on MRI in some patients after ulnar collateral ligament (UCL) reconstruction of the elbow. The etiology of this high signal is unclear and not described in literature. The hypothesis is that the edema we see on post-operative MRI is related to palmaris longus graft harvest rather than secondary to other causes of muscle edema such as denervation or muscle strain. METHODS AND MATERIALS: An IRB waiver-approved, retrospective search of our radiology database was conducted using the keywords "ucl," "elbow," and "reconstruction" between 1/01/2012 and 1/01/2022, with search parameters set as MRI for exam type. The images were reviewed to evaluate for high signal at the flexor pronator mass by a junior and a senior musculoskeletal radiologist. The surgical notes were then reviewed in electronic medical record system to see which graft was used for the UCL reconstruction. RESULTS: The cohort comprised of 33 patients (1 female/32males, 14-51 years old) who had undergone UCL reconstructions. Four patients were excluded from the study secondary to the surgical note not specifying which graft was used. The surgical and imaging dates were also recorded with the largest time gap of 7 years between the surgery and imaging. Seventeen of the 29 patients had palmaris longus harvested from the ipsilateral arm, 1 patient had palmaris longus harvested from the contralateral arm, 2 patients had an internal brace, and 9 patients had a hamstring graft. Seventeen out of 17 (100%) patients with ipsilateral palmaris longus graft demonstrated focal edema at the flexor pronator mass while 0/12 of the patients without the palmaris longus graft showed the focal edema seen by its counterparts. CONCLUSION: High signal which is commonly seen at the flexor pronator mass in patient status most UCL reconstruction of the elbow is secondary to the palmaris longus harvest rather than other etiologies such as muscle strain, retear, or trauma.

Shear wave elastography demonstrates different material properties between the medial collateral ligament and anterolateral ligament.

BACKGROUND: Anterolateral ligament and medial collateral ligament injuries could happen concomitantly with anterior cruciate ligament ruptures. The anterolateral ligament is injured more often than the medial collateral ligament during concomitant anterior cruciate ligament ruptures although it offers less restraint to knee movement. Comparing the material properties of the medial collateral ligament and anterolateral ligament helps improve our understanding of their structure-function relationship and injury risk before the onset of injury. METHODS: Eight cadaveric lower extremity specimens were prepared and mechanically tested to failure in a laboratory setting using a hydraulic platform. Measurements of surface strains of superficial surface of each medial collateral ligament and anterolateral ligament specimen were found using three-dimensional digital image correlation. Ligament stiffness was found using ultrasound shear-wave elastography. t-tests were used to assess for significant differences in strain, stress, Young's modulus, and stiffness in the two ligaments. FINDINGS: The medial collateral ligament exhibited greater ultimate failure strain along its longitudinal axis (p = 0.03) and Young's modulus (p < 0.0018) than the anterolateral ligament. Conversely, the anterolateral ligament exhibited greater ultimate failure stress than the medial collateral ligament (p < 0.0001). Medial collateral ligament failure occurred mostly in the proximal aspect of the ligament, while most anterolateral ligament failure occurred in the distal or midsubstance aspect (P = 0.04). INTERPRETATION: Despite both being ligamentous structures, the medial collateral ligament and anterolateral ligament exhibited separate material properties during ultimate failure testing. The weaker material properties of the anterolateral ligament likely contribute to higher rates of concomitant injury with anterior cruciate ligament ruptures.

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.

Arthroscopic rod technique compared to stress ultrasound in the dynamic evaluation of lateral ligament instabilities of the elbow.

INTRODUCTION: The purpose was to compare the arthroscopic rod technique to stress ultrasound in the dynamic assessment of lateral elbow instabilities. MATERIALS AND METHODS: Fifteen elbows of eight specimen with a mean age of 66.4 ± 13.3 years were assessed in a prone position following a defined dissection setup. After evaluation of the native status, an arthroscopic dissection of the radial collateral ligament (RCL) or lateral ulnar collateral ligament (LUCL), and finally of entire capsuloligamentous structures was performed. Three raters examined each state (native, RCL or LUCL lesion, complete lesion) with the arthroscopic rod technique in 90° flexion and with stress ultrasound in 30 and 90° flexion. The intra-class correlation coefficient (ICC) was calculated to assess the interrater reliability as well as test-retest reliability for each testing modality (arthroscopy and ultrasound). RESULTS: The arthroscopic rod technique showed a superior interrater and test-retest reliability of 0.953 and 0.959 (P < 0.001), respectively, when compared to stress ultrasound with an ICC of 0.4 and 0.611 (P < 0.001). A joint space opening during arthroscopy of > 6 mm humero-ulnar or > 7 mm humero-radial was indicative for a lateral collateral ligament lesion. However, a differentiation between an isolated RCL or LUCL tear was not possible. A lateral joint opening of ≥ 9 mm was only observed in complete tears of the lateral capsuloligamentous complex. CONCLUSIONS: The arthroscopic rod technique showed a superior interrater and test-retest reliability when compared to stress ultrasound. Arthroscopic assessment for radial elbow instability was found to be reliable and reproducible. A joint gapping ≥ 9 mm in the arthroscopic evaluation is a sign for a complete insufficiency of the radial capsuloligamentous complex. However, it is not possible to precisely distinguish between a lesion of the RCL or LUCL by arthroscopy. On the basis of our results, dynamic ultrasound testing may be inappropriate to objectify lateral elbow instability.

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.

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.

Stress radiographic assessment of collateral ligament constraints on the feline tarsocrural joint.

INTRODUCTION: This cadaveric study describes the collateral ligament constraints on the feline tarsocrural joint using stress radiography. METHODS: Thirty-six feline cadaveric hindlimbs free of orthopaedic disease were placed in a custom-made jig and controlled stress radiography was performed before and after transection of one, or both collateral ligaments. Changes in varus and valgus deviation and pronation and supination were measured at three limb angles (extension, 120o flexion and 90o flexion). RESULTS: There was a significant positive percentage change in the mean angle of varus deviation after transection of the fibulocalcaneal ligament at all limb positions (extension: 41%, 120°: 78%, 90°: 63%). There was a significant positive percentage change in the mean angle of varus deviation after transection of the fibulotalar ligament at extension (14%). There was a significant positive percentage change in the mean angle of varus deviation after transection of both fibulocalcaneal and fibulotalar ligaments at all limb positions (extension: 58%, 120°: 67%, 90°: 67%), and in the mean angle of valgus deviation (100%) and supination (89%) at 90 degrees flexion. There was a significant positive percentage change in the mean angle of valgus deviation after transection of the tibiocentral ligament at all limb positions (extension: mean 79%, 120°: 43%, 90°: 49%) and the mean angle of pronation at 120 degrees flexion (10%). There was a significant positive percentage change in the mean angle of varus deviation after transection of the tibiotalar ligament at extension (11%) and at 90 degrees flexion (54%) and in the mean angle of pronation at all limb positions (extension: 11%, 120°: 19%, 90°: 32%). There was a significant positive percentage change in the mean angle of valgus deviation (extension: 255%, 120°: 172%, 90°: 176%) and pronation (extension: 58%, 120°: 134%, 90°: 76%) after transection of the tibiocentral and tibiotalar ligaments at all limb positions and in the mean angle of varus deviation at extension (13%) and 90 degrees flexion (69%). CONCLUSION: The medial collateral ligaments prevent against excessive valgus deviation and pronation, and the lateral collateral ligaments prevent against excessive varus deviation and supination. At 90 degrees flexion subluxation of the talus occurs on the ipsilateral side of the ligament injury resulting in an additional direction of instability.

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.

Midterm clinical outcomes of collateral ligament repair of the thumb and lesser digits: a retrospective analysis of 35 cases.

BACKGROUND: Finger collateral ligament injuries are common, and conservative treatment usually works well. However, complete ruptures that lead to instability could cause painful disability. This study presents our clinical experience and a qualitative functional evaluation following the surgical repair of the thumb and proximal interphalangeal (PIP) joint collateral ligament ruptures. METHODS: Thirty-five patients (22 men and 13 women), diagnosed via a physical examination and magnetic resonance imaging (MRI) with a total collateral ligament rupture in the metacarpophalangeal thumb (16) and PIP joints of the lesser digits (19) and treated surgically, were evaluated retrospectively. The limited range of motion; functional score by Saetta; disabilities of the arm, shoulder, and hand (DASH) score; pre- and post-operative pain, deformity level; and post-operative ability to grip keys, buttons, and jars were measured. The significance of the change between the pre and post-operative visual analog scale for pain (VAS) scores were evaluated using the Wilcoxon signed-rank test. The difference between the lesser digits and thumb groups by patient age was evaluated using the Mann-Whitney-U test. All data, such as the mean, range, and standard deviation, were calculated using SPSS. RESULTS: The mean pre- and post-operative VAS scores were 4.8 (from 3 to 7) and 0.91 (0 to 4), respectively. The mean post-operative limitation in the range of motion was 9.78° (s = 14.47) for lesser digits and 6.87° (s = 12.29) for the thumb. According to Seatta et al., the final functional score was 62.5% excellent, 25% good, and 12.5% moderate for the thumb and 84.2% excellent, 10.5% good, and 5.3% poor for the lesser digits. The mean post-operative DASH score was 13.55 (SD: 8.77) for lesser digits and 14.22 (SD: 8.9) for the thumb. The mean contralateral (healthy) hand DASH score was 0.75 (SD: 1.05) for lesser digits and 0.75 (SD: 1.05) for the thumb. For the thumb and lesser digits, the z-scores were - 3.55 and - 3.787, respectively, and the progress of the VAS score was significant (p < 0.05). CONCLUSION: After a 40-month follow-up for 35 acute, subacute, and chronic cases, the results suggest that direct and suture-anchor repairs are feasible, painless treatments associated with good finger function.

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.

Assessment of knee collateral ligament stiffness by strain ultrasound elastography.

BACKGROUND: Knowledge of the biomechanics of the normal collateral ligaments is important to secure optimal stability of the knee following injury. Various in vitro methods have been described in evaluating the biomechanics of these ligaments. However, a method of direct evaluation has not been reported. OBJECTIVE: To determine the stiffness characteristics of the collateral ligaments of the knee using strain ultrasound elastography. METHODS: Strain ultrasound elastography was performed on different components of the collateral ligaments in various angles of knee flexion in 18 healthy males (36 ligaments). We measured relative stiffness of the ligaments using strain ratio (SR = target tissue strain/reference strain). A lower strain ratio indicates higher relative stiffness. RESULTS: There was moderate to excellent intra- and inter-rater agreement for strain ratio measurements in all ligament portions. Strain ratios were lowest at 0° in all three ligaments, indicating high relative stiffness. In the superficial and deep medial collateral ligaments, the strain ratio increased with increasing knee flexion, whereas in the lateral collateral ligament, stiffness showed a tendency to fluctuate. CONCLUSION: Strain ultrasound elastography is a reliable tool for monitoring relative stiffness of the collateral ligaments of the knee and is easily applied to the routine clinical setting.

Sites of flexor-pronator muscle injury and relationship between ulnar collateral ligament injury and flexor-pronator muscle injury in baseball players: a retrospective cohort study.

BACKGROUND: Ulnar collateral ligament (UCL) and flexor-pronator muscle (FPM) injuries are common in baseball players. However, the sites of FPM injuries and the relationship between UCL and FPM injuries in baseball players have not been fully clarified. The purpose of this study was to identify the sites of FPM injuries and to determine the relationships of location and severity of UCL injury with the presence of FPM injuries in baseball players. METHODS: UCL and FPM injuries were diagnosed using magnetic resonance imaging in 99 baseball players. The sites of FPM injuries were identified on coronal, sagittal, and axial images. UCL injury severity was classified into four grades: chronic changes, low-grade partial tear, high-grade partial tear, and complete tear. UCL injury location was classified as proximal UCL tear or distal UCL tear. All images were assessed by a musculoskeletal radiologist and an orthopedic surgeon. RESULTS: Combined UCL and FPM injuries were observed in 45 of 99 players, of which 40 of 45 (89%) involved injury of the flexor digitorum superficialis (FDS). All FDS injuries were in the deep layer of the muscle belly. There was no significant difference between the severity of UCL injury and presence of FPM injuries (P = .352). There was a significant association of distal UCL tears with FPM injuries (P < .001). CONCLUSION: FDS injury occurs most commonly in the muscle belly of the second and fifth digits. There may be no relationship between the severity of UCL injury and presence of FPM injury in baseball players. FPM injuries may be a contributing factor in the failure of nonoperative management of distal UCL tears in baseball players.

Near infrared spectroscopic evaluation of biochemical and crimp properties of knee joint ligaments and patellar tendon.

Knee ligaments and tendons play an important role in stabilizing and controlling the motions of the knee. Injuries to the ligaments can lead to abnormal mechanical loading of the other supporting tissues (e.g., cartilage and meniscus) and even osteoarthritis. While the condition of knee ligaments can be examined during arthroscopic repair procedures, the arthroscopic evaluation suffers from subjectivity and poor repeatability. Near infrared spectroscopy (NIRS) is capable of non-destructively quantifying the composition and structure of collagen-rich connective tissues, such as articular cartilage and meniscus. Despite the similarities, NIRS-based evaluation of ligament composition has not been previously attempted. In this study, ligaments and patellar tendon of ten bovine stifle joints were measured with NIRS, followed by chemical and histological reference analysis. The relationship between the reference properties of the tissue and NIR spectra was investigated using partial least squares regression. NIRS was found to be sensitive towards the water (R2CV = .65) and collagen (R2CV = .57) contents, while elastin, proteoglycans, and the internal crimp structure remained undetectable. As collagen largely determines the mechanical response of ligaments, we conclude that NIRS demonstrates potential for quantitative evaluation of knee ligaments.

MRI in acute simple elbow dislocations: correlation of preoperative imaging and intraoperative findings of collateral ligaments and associated soft tissue injuries.

PURPOSE: The aim of our study was the evaluation of correspondence among collateral ligaments and other soft tissue injuries detected by MRI and by intraoperative findings in a consecutive series of patients treated for simple elbow dislocation. METHODS: After clinical and MRI examination, 16 out of 59 consecutive patients with moderate or severe instability after simple elbow dislocation were addressed to surgical treatment. There were 14 men and 2 women. The mean age was 39.6 years (range 16-69 years). RESULTS: MRI showed full-thickness lesion of MCL in 9/16 patients (53.3%) and partial lesion in 6/16 patients (40%), and in 1 case, the MCL was considered intact. On the lateral side, MRI showed complete injury of LCL in 7/16 patients (46.6%) and partial injury in 7/16 patients (40%). No lesions of LCL were observed in 2 patients (13.4%). MCL was surgically explored in all the patients. We observed 10/16 full-thickness lesions (62.5%) and 6/16 partial lesions (37.5%). LCL was surgically explored in 11/16 patients. We observed 6/11 full-thickness lesions (54.6%) and 5/11 partial lesions (45.4%). In 3 cases, associated soft tissue injuries were detected. The rate of concordance between MRI and surgical findings was 87.5% (14/16 cases) on the medial side and 90.9% (10/11 cases) on the lateral side. CONCLUSION: Our study demonstrated that MRI is a reliable and useful tool to investigate collateral ligaments and soft tissue injuries around the elbow and to plan the most adequate surgical treatment.

[Prevalence of injury of the medial collateral ligament of the knee assessed by magnetic resonance]. / Prevalencia de lesión del ligamento colateral medial de la rodilla valorada por resonancia magnética.

INTRODUCTION: The medial collateral ligament (MCL) is one of the main stabilizers of the knee, but its injury occurs in conjunction with other ligaments. OBJECTIVE: To determine the prevalence of MCL lesions by magnetic resonance imaging, their degrees and associated lesions in our institution. MATERIAL AND METHODS: Retrospective study from January to April 2018 where KNEE MRIs were evaluated where the MCL lesion was presented to evaluate the degree and type of associated injuries. RESULTS: We included 368 studies, prevalence of isolated MCL lesion of 3.07%, grade I and grade II, prevalence of concomitant MCL lesions was 17.66% grade I (75%), grade II (15%) and grade III (3%). Associated injuries were medial meniscus injury (46.15%), anterior cruciate ligament injury (30.7%), isolated bone contusion (18.46%), chodral injuries (37.58%), medial vastus injury (14.51%), patellar medial retinacular injury (14.51%), vastus lateral injury (9.23%), posterior cruciate ligament injury (6.15%), lateral meniscus injury (4.61%), iliotibial band tenosynovitis (4.61%), medial facet avulsion fracture (3.07%), Pes Anserine tenosynovitis (3.07%). CONCLUSION: Prevalence of 17.66% of the MCL injuries in our hospital by magnetic resonance, the first 2 degrees predominate, with a wide spectrum of associated knee injuries.

INTRODUCCIÓN: El ligamento colateral medial (LCM) es uno de los principales estabilizadores de la rodilla, pero su lesión se presenta en conjunto con otras lesiones ligamentarias. OBJETIVO: Determinar la prevalencia de lesiones del LCM por resonancia magnética, sus grados y lesiones asociadas en nuestra institución. MATERIAL Y MÉTODOS: Estudio retrospectivo de Enero a Abril de 2018, se evaluaron resonancias magnéticas de rodilla donde se presentó lesión del LCM para evaluar grado y tipo de lesiones asociadas. RESULTADOS: Se incluyeron 368 estudios, prevalencia de lesión aislada del LCM de 3.07%, una grado I y una grado II, la prevalencia de lesiones de LCM concomitantes fue de 17.66%, grado I (75%), grado II (15%) y grado III (3%). Las lesiones asociadas fueron lesión del menisco medial (46.15%), lesión del ligamento cruzado anterior (30.7%), contusión ósea aislada (18.46%), lesiones condrales (37.58%), lesión de vasto medial (14.51%), lesión del retináculo medial patelar (14.51%), lesión del vasto lateral (9.23%), lesión del ligamento cruzado posterior (6.15%), lesión del menisco lateral (4.61%), tenosinovitis banda iliotibial (4.61%), fractura de avulsión de la faceta medial (3.07%), tenosinovitis de la Pes Anserinus (3.07%). CONCLUSIÓN: Prevalencia de 17.66% de lesiones del LCM en nuestro hospital por resonancia magnética, predominan los dos primeros grados con un espectro amplio de lesiones asociadas de la rodilla.

Cartilage Degeneration of the Metacarpal Condyle and Enthesopaties of The Collateral Ligaments of Equine Metacarpophalangeal Joint.

Articular degeneration can be characterized by fibrillation and eburnation of the articular layers of the metacarpophalangeal (MP) joint. Structural changes within the articular joint predispose the development of osteophytes, enthesophytes and, in many cases is associated with changes the collateral ligaments of the MP joint. The aim of the present study was to investigate the relationship between degenerative processes of the articular cartilage and the enthesopathies of collateral ligaments (superficial or deep portion) of the equine MP joint, using radiographic, ultrasonographic and anatomopathological exam, as well as establishing their sensitivity. Thirty equine forelimbs were selected from animals that died due to various clinical conditions with an average age of 5.7 years which came from a private clinic or sent to the Laboratory of Veterinary Pathology of UFSM. The specimens were placed in a hydraulic press and submitted to radiographic evaluation of the MP joint (lateromedial, flexed lateromedial, dorsopalmar, dorsolateral-palmaromedial oblique 450 and dorsomedial-palmarolateral oblique 450 projections). Transversal and longitudinal ultrasound images of the dorsal and collateral aspect of the MP joint were obtained using a Sonosite Edge machine with a 5 to 10 MHz linear transducer. Subsequently, the specimens were sent for gross and histopathological examination. A highly positive correlation (P value <.001) was observed between ultrasonographic and macroscopic techniques, showing a relationship between the cartilaginous degenerations of the MP joint and the medial and lateral LC enthesopathies.

Elbow Instability.

The stability of the elbow is based on a combination of primary (static) and secondary stabilizers (dynamic). In varus stress, the bony structures and the lateral ulnar collateral ligament (LUCL) are the primary stabilizers, and in valgus stress, the ulnar collateral ligament (UCL) is the primary stabilizer. The flexor and extensor tendons crossing the elbow joint act as secondary stabilizers. Elbow instability is commonly divided into acute traumatic and chronic instability. Instability of the elbow is a continuum, with complete dislocation as its most severe form.Posterolateral rotatory instability is the most common elbow instability and can be detected at imaging both in the acute as well as the chronic phase. Imaging of suspected elbow instability starts with radiographs. Depending on the type of injury suspected, it is followed by magnetic resonance imaging (MRI) or computed tomography evaluation for depiction of a range of soft tissue and osseous injures. The most common soft tissue injuries are tears of the LUCL and the radial collateral ligament; the most common osseous injuries are an osseous LUCL avulsion, a fracture of the coronoid process, and a radial head fracture.Valgus instability is the second most common instability and mostly detected in the chronic phase, with valgus extension overload the dominant pattern of injury. The anterior part of the UCL is insufficient in valgus extension overload due to repetitive medial tension seen in many overhead throwing sports, with UCL damage readily seen at MRI.