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    Distal Ulnar Collateral Ligament Rupture in a Professional Baseball Player

    A 25-year-old male professional baseball player presented with pain in the right elbow following a specific pitch. MRI demonstrates a tear of the distal aspect of the ulnar collateral ligament with concomitant degeneration of the proximal ligament. What is the next step?

    Authors

    Brandon J. Erickson, MD; Meghan E. Bishop, MD; and Anthony A. Romeo, MD

    Introduction

    Tears of the medial ulnar collateral ligament (UCL) of the elbow have become common in overhead athletes over the last 10 years. [1,2] Many risk factors for UCL injury have been identified, including workload, training with weighted baseballs, and fastball velocity. [3-6]

    The UCL is the primary restraint to valgus stress at the elbow. [7] Although the bony congruency and muscles and tendons that surround the elbow contribute 50% of the valgus stability of the elbow, the UCL bears approximately 50% of the load each time a baseball player throws a baseball. [8,9] Unfortunately, this amount of load places the UCL near failure with every pitch. Hence, as pitching velocity increases, stress on the medial elbow also increases and the UCL approaches failure with each throw. Recent evidence has shown that 25% of major league and 15% of minor league pitchers have a history of UCL reconstruction, commonly known as Tommy John surgery. [10]

    Several treatment options are available to manage UCL tears:

    • Non-operative management
    • Biologic augmentation to non-operative management
    • UCL repair
    • UCL reconstruction

    Treatment for a UCL tear depends on the patient. Patient age, tear pattern, and location of the tear are among the many factors taken into consideration when determining the ideal treatment for a specific patient. The ultimate goal is to allow the player to return to sport (RTS) at the same or higher level as before the injury.

    Case Presentation

    A 25-year-old male professional major league baseball player presented 4 days after experiencing significant pain in his right elbow just distal to his medial epicondyle. He had had some elbow issues in the past, but nothing that kept him out for an extended period of time.

    This time, the pain started acutely after he threw a fastball in a game. He felt the pain before he let the ball go. He did not have any pain or discomfort in his shoulder or wrist. He denied any numbness or tingling in his arm or hand during that pitch or previously when he was throwing. He also denied any significant prior complaints with this arm. He had been treated non-operatively for a flexor pronator strain 2 years prior, with successful RTS.

    He had not thrown since his injury 4 days prior. He did not complain of any significant pain at rest, and most activities of daily living did not bother his elbow.

    Physical Exam

    • Height: 6 feet, 2 inches; weight: 210 pounds; BMI: 26.96 kg/m2
    • No bruising or swelling on inspection
    • Discomfort with palpation of the distal aspect of the UCL
    • No tenderness to palpation over the medial epicondyle
    • Painless range of motion of the elbow from 5 to 140 of flexion/extension and 75 of pronation/supination
    • No pain with resisted wrist flexion/extension or forearm pronation/supination
    • Negative temple test
    • Positive moving valgus stress test and milking maneuver
    • Negative Tinel’s at the elbow
    • Neurovascularly intact distally

    Imaging

    Radiographs of the elbow did not show any osseous abnormalities, such as sublime tubercle enthesophyte or posteromedial osteophyte.

    Coronal magnetic resonance image (MRI) of the right elbow demonstrated a complete tear of the distal UCL with associated degeneration of the more proximal aspect of the UCL (Figure 1).

    Figure 1. Coronal MRI shows a tear of the distal aspect of the UCL (white arrowhead) and degeneration within the proximal aspect of the UCL.

    Diagnosis

    • Complete rupture of the distal UCL with associated UCL degeneration

    Treatment

    A long discussion with the athlete, his family, his agent, and the coaching and training staff followed his diagnosis. The options presented to the patient included:

    • Non-operative treatment with rest and a return to throwing program
    • Biologic augmentation with platelet rich plasma (PRP)
    • Operative treatment with surgical reconstruction of the torn UCL

    Given the location of the tear and degeneration of the ligament, PRP was not felt to be the ideal choice based on previous evidence. [11-13] Similarly, repair of the UCL was discussed, as it has shown promising results. [14,15] However, given his level of play, age, mileage on his elbow, and appearance of the rest of the UCL on MRI, UCL repair was not felt to be the best option for a successful outcome.

    We discussed the nature of UCL reconstruction and the associated risks, including injury to the ulnar nerve, potential wound complications, and possibility of re-tear, as well as the postoperative recovery and rehabilitation protocol. The patient communicated his understanding of the risks, and after further discussion with the patient, coaching and training staff, agent, and family, the decision was made to proceed with surgical reconstruction.

    Procedure

    Setup/Positioning/Prepping

    • Use a non-sterile, 18-inch tourniquet.
    • Place the patient in the supine position on the table, with the operative arm outstretched on a hand table.
    • Rotate the bed 90° so that the operative hand is facing out toward the room.
    • Prep and drape in the usual sterile fashion. If the preoperative plan is to use a hamstring graft, ensure that the knee is prepped and draped as well.

    Harvesting the Palmaris

    • Using a 15 blade, make a 2-cm transverse incision at the distal wrist flexion crease, centered over the palmaris.
    • Locate the flexor carpi radialis (FCR). The palmaris is just ulnar to the FCR and is very superficial.
    • Dissect down to the palmaris and isolate it.
    • Put a hemostat under the palmaris and pull on it to make sure the wrist flexes. Do not go deep here because the median nerve is very close.
    • Prep the tendon distally with a high-tensile suture. Flex the wrist to allow for as much length as possible. Spread the hemostat that’s under the palmaris to hold tension on the tendon.
    • Throw running, locking Krakow stitches heading from distal to proximal: 3 throws up, 1 across, and then 3 throws back (distal).
    • Flex the wrist and release the palmaris distal to where it has been prepped.
    • Pass the sutures into the 4-mm closed tendon stripper and pass the palmaris through this, aiming for the medial epicondyle, until the tendon is amputated.
    • Place the tendon in a wet sponge on the back table.
    • Close this incision with simple interrupted throws using 4-0 nylon suture.

    Surgical Technique

    • After inflating the tourniquet to 250 mmHg, make a 10-cm incision centered over the medial epicondyle, which starts about 3 cm proximal to the medial epicondyle and extends distally (Figure 2). The incision should be distal and proximal enough to expose the ulnar nerve so that it can be avoided when drilling the ulnar tunnel and the exit holes, respectively.

    Figure 2. Intraoperative image shows placement of the incision for an ulnar collateral ligament reconstruction.

    • Pinch the medial epicondyle between the thumb and index finger and incise over the medial epicondyle.
    • Incise through the skin, use bipolar to control skin bleeders, and then use a sponge to clean the fat/medial antebrachial cutaneous nerve (MABCN) off the flexor-pronator fascia (Figure 3).

    Figure 3. Intraoperative image shows the exposed fascia of the flexor pronator mass.

    • Avoid the MABCN as it courses from anterior to posterior, usually in the posterior aspect of the incision. Using the sponge to sweep tissue anteriorly and posteriorly helps keep the nerves intact. The MABCN should be preserved as best as possible.
    • Split the flexor-pronator fascia. If present, the raphe within the flexor-pronator fascia is a good landmark to make the muscle split.
    • Take this split all the way down to the native UCL and clean off any muscle that is on the UCL. A periosteal elevator can help clean off the UCL.
    • Use the long end of a Senn retractor to pull the flexor pronator musculature apart anteriorly and posteriorly.
    • Once the level of the native UCL is defined, use a blunt-tipped deep Gelpie to hold the flexor pronator musculature apart. An army-navy retractor placed distally will help with exposure.
    • Bluntly and gently dissect the ulnar nerve off the posterior aspect of the native UCL.
    • Once the native UCL is exposed, split it in line with its fibers. Leave enough tissue anteriorly and posteriorly to close later.
    • Sharply excavate any ossicle in the UCL.
    • Apply a valgus stress to confirm that the UCL is incompetent, as evidenced by gapping. It helps to place towels under the elbow so that the assistant can apply this force on the elbow while supinating the hand.
    • Use a knife to elevate the periosteum/native UCL off the ulna anteriorly and posteriorly. The forearm should be supinated when working on the posterior ulna.
    • Use the 3.0-mm burr to create 2 converging holes on either side of the sublime tubercle (anterior and posterior to it). Alternatively, a drill guide with a 3.5-mm drill bit can be used to drill the converging holes. If a hamstring graft is going to be used, the holes should be 4.5 mm to accommodate the larger graft.
    • Leave 4 mm to 5 mm between the proximal aspect of the tunnel and the joint line and leave an 8-mm to 10-mm bone bridge in between the converging holes.
    • Use a small curved curette and connect the 2 holes, taking care not to violate the bone bridge.
    • Place a suture passer through the tunnel, and then pass a suture through the tunnel that will be used later to pass the graft.
    • Attention is now turned to creating the humeral socket.
    • Expose the medial epicondyle, making sure to get deep and lateral to the overhanging bump of the medial epicondyle.
    • Use the knife to scrape off the native UCL, heading lateral (deep into the incision) until the most lateral aspect of the deep surface of the epicondyle is exposed.
    • Use a skin hook to retract the cut UCL anteriorly.
    • Use a 4.5-mm burr or drill to create a 15-mm socket on the humerus, at the anatomic insertion of the UCL. The medial epicondyle can fracture if the hole is too close to its edge.
    • Use an electrocautery to make a small incision down to bone on the anterior aspect of the medial epicondyle, where the flexor-pronator inserts. This will be the location of the exit drill holes.
    • Make a 1.5-mm drill hole, starting on the posterior aspect of the medial epicondyle, exiting into the 4.5-mm socket that was just drilled. Retract the ulnar nerve posteriorly to protect it if necessary
    • Create a second 1.5-mm drill tunnel from the anterior aspect of the medial epicondyle, just anterior to the medial intermuscular septum. The bone bridge between the 2 exit holes should be at least 1.0 cm
    • Use a suture passing device to place a looped passing suture in both tunnels for later use. The loop should be distal (out the humeral socket).
    • Suture the native UCL closed (side to side), from distal to proximal. Avoid close off the humeral tunnel while tying down these sutures.
    • Pass the graft through the ulnar tunnel from anterior to posterior (Figure 4). Sterile mineral oil can help pass this graft if needed.

    Figure 4. Intraoperative image shows the graft that has been passed through the ulnar tunnel. One end has been passed into the humeral socket, while the free end is held up against the medial epicondyle to determine graft length.

    • Place the posterior limb of the graft (the prepped end) into the humeral socket using the posterior passing suture. This docks the posterior end of the graft into the medial epicondyle.
    • Pull significant tension on the end of the graft docked into the medial epicondyle to make sure it is completely seated. Take up any slack in the system before moving to the next step.
    • Put the forearm in maximal supination and place varus stress on the elbow. Then, lay the anterior limb of the graft over the medial epicondyle and mark with a marking pen just distal to where the socket ends to ensure that all of the graft will fit in the tunnel before having it bottom out.
    • Prep the second end of the graft in a similar manner as the first end (bullet the end). If the graft bottoms out before full tension is taken up, the graft will need to be removed and cut shorter.
    • Next, pass the anterior limb into the humerus using the previously placed passing stitch. Watch and feel the limbs of the graft dock into the humerus, making sure that both ends go in and are not getting hung up.
    • Cycle the elbow to minimize creep. Both ends of the graft should be tensioned extremely tightly.
    • Flex and extend the elbow. The anterior limb of the UCL graft should be tight in extension and lax in flexion, and the posterior limb of the UCL graft should be lax in extension and tight in flexion.
    • Tie the sutures over the epicondylar bone bridge with the elbow in 30° to 45° of flexion, with varus stress placed on the elbow and the forearm in maximal supination. Check tension on both limbs of the graft.
    • Tie the sutures together and then suture together the 2 limbs of the reconstructed UCL (Figure 5).

    Figure 5. Intraoperative image shows the reconstructed ligament that has been sutured together.

    • If transposing the nerve, transpose it anterior to the medial epicondyle.
    • Deflate the tourniquet and obtain hemostasis. Close the incision in layered fashion.
    • Place the arm in a hinged elbow brace locked in 70 of flexion.

    Postoperative Follow Up

    Week 1

    • The elbow is immobilized in a brace at 70 flexion for 7 to 10 days, with the wrist free but in a sling.
    • The dressing is changed at 7 to 10 days after surgery.

    Week 2

    • The patient begins active range of motion (ROM) and grip strength in the brace.
    • The brace is adjusted to 15 (locked) extension and to full flexion.

    Week 4

    • Use of the brace is discontinued.
    • The patient advances shoulder and elbow ROM from passive to active assisted to active ROM as tolerated.
    • The patient begins muscle strengthening exercises for the wrist, forearm, elbow, and shoulder.
    • The patient advances strengthening as tolerated, avoiding aggressive weight-lifting until 12 weeks after surgery, especially chest flies or other lifts that directly stress the ligament.
    • Valgus stress on the elbow is avoided until at least 2 months after surgery.
    • The patient may begin total body conditioning and aerobic training.

    Month 4

    • The patient may begin an interval throwing program, progressing from 45 feet up to 180 feet.
    • Pitchers are asked to avoiding throwing beyond 120 feet, while infielders should avoid throwing beyond 150 feet.
    • The patient may progress from one distance level to the next when the following criteria are met:
      • There is no pain or stiffness while throwing.
      • There is no significant pain or stiffness after throwing.
      • Strength is good throughout the final set, with little fatigue.
      • The throwing motion is effortless and fundamentally sound.
      • Accuracy is consistent and throws are online.

      For pitchers, the mound program begins at the completion of the 120-foot level. The catcher is initially moved forward but throwing with a pitching motion is reserved for the mound. No flat ground pitching is allowed.

    Months 9 through 18

    • Return to competition is permitted when the following conditions are met:
      • Trunk, scapula, shoulder, and arm muscle strength and balance have returned to normal.
      • There is no pain while throwing.
      • Throwing balance, rhythm, and coordination have been reestablished.

    Surgical Pearls

    • The palmaris is often diminutive in patients who have this tendon on only 1 side. In that case, consideration should be given to using a hamstring graft. Recent evidence suggests that hamstring grafts should be harvested from the contralateral (landing) leg. [16-18]
    • Leave a good-sized bone bridge between the holes. If the bone bridge breaks, the technique must be altered to change the type of fixation.
    • Understanding where the ulnar nerve is at all times during this procedure is of paramount importance. The authors do not routinely transpose the nerve unless the patient has preoperative ulnar nerve symptoms.
    • The graft must be tensioned with a varus stress placed on the elbow to avoid laxity.

    Discussion

    Ulnar collateral ligament tears are becoming more common in overhead athletes of all levels, especially professional athletes. These injuries can occur as a 1-time, acute traumatic injury or from chronic wear and tear due to repeated stress.

    The case described in this article involves a pitcher who not only has degeneration of his UCL over time, but also has an acute, traumatic distal UCL rupture that prevented RTS at a high level. Unfortunately, the blood supply to the distal UCL is inferior to that of the proximal UCL. [19,20] Healing is more difficult in distal than in proximal UCL tears, and as a result, distal UCL tears do not often do as well with non-operative management. [13]

    Ramkumar et al [21] evaluated 58 athletes with UCL tears to determine predicative factors of failure of non-operative management. The authors concluded that patients likely to fail non-operative treatment had complete distal tears, whereas those with proximal partial tears were more amenable to non-operative management.

    Similarly, Frangiamore et al [13] evaluated 32 pitchers and looked at MRI predictors of failure following non-operative management. They also found that distal UCL tears were significantly more likely to fail non-operative management than proximal tears. Hence, distal tears appear to do worse with non-operative treatment, possibly secondary to the broad but narrow insertion on the sublime tubercle for the UCL or secondary to the poor blood supply to the sublime tubercle. [19,20,22]

    There are 2 main options for surgical treatment of UCL tears: repair and reconstruction. Ulnar collateral ligament repair was first described by Conway and Jobe in 1992, but the results were suboptimal, with an RTS rate of 71.4%. [23] The original technique has been modified several times and recent reports of UCL repair have been much better, with Savoie et al reporting an RTS rate of 97%. [24]

    The technique was further modified by Dugas et al, [25] who introduced the addition of an internal brace to augment the repair and allow a faster RTS. The internal brace has been shown to be biomechanically superior to the modified Jobe technique at time zero, as it is more resistant to gapping at low cyclic loads. [25]

    Dugas et al [15] also reported 1-year results following UCL repair in 111 overhead athletes. They performed UCL repair if there was a clear avulsion of the UCL off the sublime tubercle or medial epicondyle and if the remainder of the ligament was of good-quality tissue. The RTS rate was 92% at an average of 6.7 months, which is significantly faster than the 12 to 18 months it often takes players to RTS following reconstruction. [2,15,26] A drawback of the study by Dugas et al [15] is that only 1 patient (<1%) was a professional baseball player. Although the results of this technique are extremely promising, further work is needed to determine its effectiveness in professional athletes.

    The case described in this report involved a professional baseball player with an abnormal ligament; he was not an ideal candidate for UCL repair. He underwent UCL reconstruction instead, from which he recovered well. He was able to RTS at 14 months postoperatively at the same level of play.

    Studies of outcomes following UCL reconstruction often report RTS at the same or higher level of 80% to 90%. [1,2] This RTS rate does not appear to differ based on graft choice or management of the ulnar nerve. [27,28] In overhead athletes who sustain a tear of the UCL and wish to continue to compete at a high level, UCL reconstruction is, therefore, a good option to facilitate successful RTS.

    Author Information

    Brandon J. Erickson, MD, is an orthopaedic sports medicine surgeon at The Rothman Orthopaedic Institute, New York, New York. Meghan E. Bishop, MD, is an orthopaedic sports medicine surgeon at The Rothman Orthopaedic Institute, New York, New York. Anthony A. Romeo, MD, is an orthopaedic shoulder, elbow, and sports surgeon and chief of orthopaedics at The Rothman Orthopaedic Institute, New York, New York, as well as the past president of the American Shoulder and Elbow Surgeons (ASES).

    Sports Medicine Editor, Rothman Institute Grand Rounds

    Sommer Hammoud, MD

    Disclosures: The authors have no disclosures relevant to this article.

    References

    1. Cain EL, Jr., Andrews JR, Dugas JR, et al. Outcome of ulnar collateral ligament reconstruction of the elbow in 1281 athletes: Results in 743 athletes with minimum 2-year follow-up. Am J Sports Med. 2010;38(12):2426-2434.
    2. Erickson BJ, Gupta AK, Harris JD, et al. Rate of Return to Pitching and Performance After Tommy John Surgery in Major League Baseball Pitchers. Am J Sports Med. 2013.
    3. Chalmers PN, Erickson BJ, Ball B, Romeo AA, Verma NN. Fastball Pitch Velocity Helps Predict Ulnar Collateral Ligament Reconstruction in Major League Baseball Pitchers. Am J Sports Med. 2016.
    4. Fleisig GS, Andrews JR, Cutter GR, et al. Risk of serious injury for young baseball pitchers: a 10-year prospective study. Am J Sports Med. 2011;39(2):253-257.
    5. Keller RA, Mehran N, Khalil LS, Ahmad CS, ElAttrache N. Relative individual workload changes may be a risk factor for rerupture of ulnar collateral ligament reconstruction. J Shoulder Elbow Surg. 2017;26(3):369-375.
    6. Reinold MM, Macrina LC, Fleisig GS, Aune K, Andrews JR. Effect of a 6-Week Weighted Baseball Throwing Program on Pitch Velocity, Pitching Arm Biomechanics, Passive Range of Motion, and Injury Rates. Sports Health. 2018;10(4):327-333.
    7. Erickson BJ, Romeo AA. The Ulnar Collateral Ligament Injury: Evaluation and Treatment. J Bone Joint Surg Am. 2017;99(1):76-86.
    8. Morrey BF, An KN. Articular and ligamentous contributions to the stability of the elbow joint. Am J Sports Med. 1983;11(5):315-319.
    9. Morrey BF, Tanaka S, An KN. Valgus stability of the elbow. A definition of primary and secondary constraints. Clin Orthop Relat Res. 1991(265):187-195.
    10. Conte SA, Fleisig GS, Dines JS, et al. Prevalence of Ulnar Collateral Ligament Surgery in Professional Baseball Players. Am J Sports Med. 2015;43(7):1764-1769.
    11. Chauhan A, McQueen P, Chalmers PN, et al. Nonoperative Treatment of Elbow Ulnar Collateral Ligament Injuries With and Without Platelet-Rich Plasma in Professional Baseball Players: A Comparative and Matched Cohort Analysis. Am J Sports Med. 2019;47(13):3107-3119.
    12. Ford GM, Genuario J, Kinkartz J, Githens T, Noonan T. Return-to-Play Outcomes in Professional Baseball Players After Medial Ulnar Collateral Ligament Injuries: Comparison of Operative Versus Nonoperative Treatment Based on Magnetic Resonance Imaging Findings. Am J Sports Med. 2016;44(3):723-728.
    13. Frangiamore SJ, Lynch TS, Vaughn MD, et al. Magnetic Resonance Imaging Predictors of Failure in the Nonoperative Management of Ulnar Collateral Ligament Injuries in Professional Baseball Pitchers. Am J Sports Med. 2017:363546517699832.
    14. Dugas JR. Ulnar Collateral Ligament Repair: An Old Idea With a New Wrinkle. Am J Orthop (Belle Mead NJ). 2016;45(3):124-127.
    15. Dugas JR, Looze CA, Capogna B, et al. Ulnar Collateral Ligament Repair With Collagen-Dipped FiberTape Augmentation in Overhead-Throwing Athletes. Am J Sports Med. 2019;47(5):1096-1102.
    16. Erickson BJ, Chalmers PN, D’Angelo J, et al. Side of Hamstring Harvest Does Not Affect Performance, Return-to-Sport Rate, or Future Hamstring Injuries After Ulnar Collateral Ligament Reconstruction Among Professional Baseball Pitchers. Am J Sports Med. 2019;47(5):1111-1116.
    17. Erickson BJ, Chalmers PN, Dugas JR, et al. Do Major League Baseball Team Physicians Harvest the Semitendinosus From the Drive Leg or Landing Leg When Performing Ulnar Collateral Ligament Reconstruction on Elite Baseball Pitchers? Orthop J Sports Med. 2017;5(7):2325967117713987.
    18. Erickson BJ, Zaferiou A, Chalmers PN, et al. Are the hamstrings from the drive leg or landing leg more active in baseball pitchers? An electromyographic study. J Shoulder Elbow Surg. 2017.
    19. Camp CL, Klinger CE, Lazaro LE, et al. Osseous Vascularity of the Medial Elbow After Ulnar Collateral Ligament Reconstruction: A Comparison of the Docking and Modified Jobe Techniques. Orthop J Sports Med. 2018;6(4):2325967118763153.
    20. Erickson BJ, Fu M, Meyers K, et al. The Middle and Distal Aspects of the Ulnar Footprint of the Medial Ulnar Collateral Ligament of the Elbow Do Not Provide Significant Resistance to Valgus Stress: A Biomechanical Study. Orthop J Sports Med. 2019;7(2):2325967118825294.
    21. Ramkumar PN, Haeberle HS, Navarro SM, Frangiamore SJ, Farrow LD, Schickendantz MS. Clinical Utility of an MRI-Based Classification System for Operative Versus Nonoperative Management of Ulnar Collateral Ligament Tears: A 2-Year Follow-up Study. Orthop J Sports Med. 2019;7(4):2325967119839785.
    22. Frangiamore SJ, Bigart K, Nagle T, Colbrunn R, Millis A, Schickendantz MS. Biomechanical analysis of elbow medial ulnar collateral ligament tear location and its effect on rotational stability. J Shoulder Elbow Surg. 2018.
    23. Conway JE, Jobe FW, Glousman RE, Pink M. Medial instability of the elbow in throwing athletes. Treatment by repair or reconstruction of the ulnar collateral ligament. J Bone Joint Surg Am. 1992;74(1):67-83.
    24. Savoie FH 3rd, Trenhaile SW, Roberts J, Field LD, Ramsey JR. Primary repair of ulnar collateral ligament injuries of the elbow in young athletes: a case series of injuries to the proximal and distal ends of the ligament. Am J Sports Med. 2008 June;36(6):1066-72. Epub 2008 Apr 28.
    25. Dugas JR, Walters BL, Beason DP, Fleisig GS, Chronister JE. Biomechanical Comparison of Ulnar Collateral Ligament Repair With Internal Bracing Versus Modified Jobe Reconstruction. Am J Sports Med. 2015.
    26. Erickson BJ, Chalmers PN, Bach BR, Jr., et al. Length of time between surgery and return to sport after ulnar collateral ligament reconstruction in Major League Baseball pitchers does not predict need for revision surgery. J Shoulder Elbow Surg. 2017;26(4):699-703.
    27. Erickson BJ, Bach BR, Jr., Cohen MS, et al. Ulnar Collateral Ligament Reconstruction: The Rush Experience. Orthop J Sports Med. 2016;4(1):2325967115626876.
    28. Erickson BJ, Cvetanovich GL, Frank RM, et al. Do Clinical Results and Return-to-Sport Rates After Ulnar Collateral Ligament Reconstruction Differ Based on Graft Choice and Surgical Technique? Orthop J Sports Med. 2016;4(11):2325967116670142.