Anterior translation and morphologic changes of the ulnar nerve at the elbow in adolescent baseball players

Characteristics of ulnar neuropathy in baseball players: Focusing on the entrapment point of the ulnar nerve and valgus instability

Background

The region where the ulnar nerve (UN) is swollen in baseball players with ulnar neuropathy is not apparent. This study investigated the UN's cross-sectional area (CSA) at each entrapment point in baseball players. We also aimed to clarify the relationship between valgus instability and the CSA of the UN.

Methods

Forty baseball players were separated into healthy and ulnar neuropathy groups. The CSA and valgus instability were measured using ultrasonography (US). Relative to the medial epicondyle (MEC), the arcade of Struthers (SA) was 5 cm proximal, the cubital tunnel was the posterior part, and Osborne's ligament was defined as 3 cm distal. The ulnohumeral joint space was imaged as a low-echo space between the distal-medial corner of the trochlea and the proximal edge of the sublime tubercle.

Results

The UN in the ulnar neuropathy group had significant swelling in the cubital tunnel and Osborne's ligament. We found a weak positive correlation between the CSA and ulnohumeral joint space, and the ulnohumeral joint space at rest and valgus stress.

Conclusion

Evaluation and treatment of UN, especially cubital tunnel and Osborne's ligament, are necessary for the rehabilitation of baseball players presenting with ulnar neuropathy and valgus instability.

Hearing and Seeing Nerve/Tendon Snapping: A Systematic Review on Dynamic Ultrasound Examination

Nerve/tendon snapping can occur due to their sudden displacement during the movement of an adjacent joint, and the clinical condition can really be painful. It can actually be challenging to determine the specific anatomic structure causing the snapping in various body regions. In this sense, ultrasound examination, with all its advantages (especially providing dynamic imaging), appears to be quite promising. To date, there are no comprehensive reviews reporting on the use of dynamic ultrasound examination in the diagnosis of nerve/tendon snapping. Accordingly, this article aims to provide a substantial discussion as to how US examination would contribute to 'seeing' and 'hearing' these pathologies' different maneuvers/movements.

Ulnar Neuritis and Its Affect on Outcomes of Elbow Ulnar Collateral Ligament Reconstruction

BACKGROUND

No study has specifically evaluated how ulnar neuritis and ulnar nerve transposition affect outcomes in baseball players undergoing ulnar collateral ligament (UCL) reconstruction (UCLR).

PURPOSE

To evaluate the effects of ulnar neuritis and ulnar nerve transposition in baseball pitchers undergoing UCLR in regard to return to sport, time to return to sport, and need for revision or additional surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

At a single institution, all consecutive baseball pitchers undergoing UCLR between 2002 and 2015 were identified. Ulnar neuritis was diagnosed preoperatively by the following criteria: ulnar nerve symptoms, Tinel sign at the elbow, symptomatic subluxation, and numbness/paresthesia in an ulnar nerve distribution of the hand. The primary outcome of the study was return to sport. The secondary outcomes of the study were time to return to sport, length of playing career, and revision or additional surgery.

RESULTS

A total of 578 UCLRs were performed in baseball players; of these, 500 UCLRs were performed in pitchers. Ulnar neuritis was diagnosed in 97 (19.4%) baseball pitchers presenting with UCL injury. There were no significant differences in patient characteristics or surgical techniques performed for reconstruction between baseball pitchers with and without ulnar neuritis. In review of injury characteristics, ulnar neuritis was significantly more likely to be diagnosed in pitchers with an acute onset of UCL injury (P = .03). Transposition of the ulnar nerve was more commonly performed in players with ulnar neuritis (47%) versus those without ulnar neuritis (10%; P = .0001). The players who had ulnar neuritis and underwent UCLR had a significantly lower odds of returning to sport (odds ratio, 0.45; P = .04); however, no significant difference was found for time to return to sport and length of playing career for those with and without ulnar neuritis (P = .38 and .51, respectively).

CONCLUSION

The study suggests that ulnar neuritis, when present preoperatively in baseball pitchers undergoing UCLR, may adversely affect their ability to return to sport, whereas ulnar nerve transposition at the time of UCLR does not alter the ability to return to sport.

The impact of pre-existing ulnar nerve instability on the surgical treatment of cubital tunnel syndrome: a systematic review

BACKGROUND

The decision to perform nerve transposition (NT) or in situ decompression (SD) during surgical treatment of cubital tunnel syndrome is often based on nerve subluxation through elbow motion. This review assesses what impact nerve instability has on study design and reported outcomes.

METHODS

A search was performed with Boolean operators: "ulnar nerve" OR "cubital tunnel" AND "decompression" OR "transposition" on PubMed, Clinical Key, and CINAHL to identify primary studies comparing NT and SD that report pre-existing nerve instability. Primary outcome was the effect of instability on study design. Secondary outcomes were nerve instability, patient-reported scores, and complications.

RESULTS

Five studies met criteria after screening 134 articles. In 3 studies, nerve instability dictated treatment. Prospective randomization was maintained in 1 study. Included cases totaled 464 SD and 304 NT. The complication rate was 8.6% overall, 4.3% for SD and 21.1% for NT. Bishop scores were 56.9% excellent and 37.3% good for stable nerves and 62.0% excellent and 29.3% good for unstable nerves.

CONCLUSIONS

Very few studies report ulnar nerve instability, and study design is biased by ulnar nerve subluxation. Outcomes showed similar symptomatic improvement for both decompressed and transposed groups with higher complication rates for the transposed group.

Skill level and forearm muscle fatigue effects on ball speed in tennis serve

This study determined the effect of skill level (ITN 3 vs. ITN 8) on the tennis serve biomechanics and analysed the impact of forearm fatigue on dominant arm mechanisms between the two groups (expert vs. non-expert tennis players). The motion capture system with 17 reflective markers attached on anatomic landmarks of the participant was used for data collection. A total of 12 expert and 11 non-expert tennis players performed the required serving tasks. The ball speed of the expert group was significantly faster than that of the non-expert group during non-fatigued and fatigued states (p < 0.001). The wrist radial/ulnar deviation angle at impact was significantly different between non-fatigued and fatigued states for top-spin (p = 0.030) and flat serves (p = 0.018). A significant increase in extensor carpi ulnaris (ECU) and extensor carpi radialis (ECR) muscle activity during extension (p < 0.010) was observed, with that of the ECU being an ulnar deviation. Both the ECU and ECR might contribute to wrist joint and racket handle stability for the coming acceleration and impact while fatigue occurs. Fatigue might substantially influence non-experts' dominant forearms because of the significantly different elbow joint angles and dominant arm syndromes they displayed as compared with the experts.

Forearm muscle activation, ulnar nerve at the elbow and forearm fatigue in overhand sports

This study examined the morphologic changes of the ulnar nerve in different elbow positions by ultrasonography and the effects of fatigue on forearm muscle control during overhand movements. We enrolled 12 tennis players who performed flat serves and 15 baseball pitchers who performed fastball pitching. The motion capture was conducted with 14 reflective markers attached on anatomic landmarks of the participant for tennis serve and baseball pitching data collection. The distance from the nerve to the medial condyle between the tennis players and baseball pitchers showed significant differences (p = 0.006) as the elbow flexed to 90°. The differences are due to the baseball player's repetitive pitching motion while such motion does not apply to tennis player. Activity of the extensor carpi radialis (ECR) during the cocking phase in the tennis serves showed significant differences (p = 0.022) between the nonfatigued and fatigued states; the maximal value was observed in the fatigued state. The significant increase in the ECR activity in the fatigued state might be responsible for grasp-and-release activities and maintaining the wrist joint stability when performing overhand movements. Forearm fatigue influenced their overhand motion ability in accurate ball control, although it did not decrease the ball speed.

Optimal Elbow Angle for Sonographic Visualization of the Ulnar Collateral Ligament

OBJECTIVE

To formally examine the sonographic appearance of the elbow ulnar collateral ligament (UCL) at 30° versus 70° of elbow flexion in asymptomatic baseball pitchers.

DESIGN

A prospective, cross-sectional design.

SETTING

Sports medicine clinic in a tertiary academic medical center.

PARTICIPANTS

Thirty asymptomatic adolescent baseball pitchers 13-18 years of age (mean 15.8 years), with at least 3 years of continuous pitching experience and no significant history of elbow pain or injury.

METHODS

Static sonographic images of the bilateral UCLs were obtained at 30° and 70° of elbow flexion by a single experienced examiner. Images were anonymized and randomized into a slide set. Three clinicians with different levels of ultrasound experience reviewed the static 30° and 70° images for each elbow and chose their preferred image based on UCL conspicuity. The clinicians reviewed a re-randomized slide set 1 week later. A different study co-investigator measured UCL cross-sectional area (CSA) on all images using ultrasound machine electronic calipers.

MAIN OUTCOME MEASURES

Preference for the sonographic conspicuity of the UCL at 30° versus 70° of elbow flexion, and UCL CSA at 30° versus 70° of flexion.

RESULTS

Each clinician demonstrated a significant preference for UCL images obtained at 70° of flexion when compared to those obtained at 30° (80.3% overall preference for 70°, P < .001). There was no statistically significant effect of clinician experience or arm dominance on image preference. The sonographically determined CSA of the UCLs were on average 1.4 mm(2) greater at 70° than at 30° of flexion (P < .001) when combining dominant and nondominant arms.

CONCLUSIONS

Static sonographic evaluation of the UCL at 70° of elbow flexion should be integrated into UCL imaging protocols. Furthermore, when performing sonographically guided procedures targeting the UCL, clinicians should consider positioning the elbow at >30° of flexion to optimize UCL conspicuity and CSA.