The Ulnar Collateral Ligament Injury: Evaluation and Treatment

Erickson, Brandon J. MD; Romeo, Anthony A. MD

Journal of Bone & Joint Surgery - American Volume: 4 January 2017 - Volume 99 - Issue 1 - p 76–86
doi: 10.2106/JBJS.16.01277
Current Concepts Review

Medial elbow pain in the throwing athlete can result from a variety of sources, including medial epicondylitis, valgus extension overload, ulnar collateral ligament (UCL) insufficiency, ulnar neuritis, and others.

Initial treatment following a UCL tear involves a period of rest (no throwing or strenuous use of the elbow) followed by rehabilitation and a graduated throwing program.

UCL reconstruction (UCLR) has become the preferred surgical treatment method for patients with a symptomatic, deficient UCL who wish to return to sports.

Several modifications to the original technique described by Jobe et al. have been proposed, including a muscle-splitting approach, a docking technique, and the use of various grafts, including hamstring autograft and several types of allografts.

The timing of return to sport following UCLR varies from patient to patient, with some patients being able to return within 12 months and others taking >18 months. Although the literature varies, typically >80% of patients are able to return to the same level of sport following UCLR.

1Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois

E-mail address for B.J. Erickson: Brandon.j.erickson@gmail.com

Article Outline

The first description of a tear of the ulnar collateral ligament (UCL) (Fig. 1) appeared in a 1946 report by Waris that focused on elbow injuries in javelin throwers1. However, it was not until 1974 that the first UCL reconstruction (UCLR) was performed by Dr. Frank Jobe on Los Angeles Dodgers pitcher Tommy John2. Several modifications of this procedure have been performed since the initial description (Table I)2-12. Although primary repair of the anterior band of the UCL also has been associated with encouraging results in nonprofessional pitchers and adolescents when performed for proper indications (proximal or distal UCL injuries that do not involve midsubstance tears), the results of primary repair in Major League Baseball (MLB) pitchers have been inferior to those of reconstruction, and thus reconstruction has become the gold standard of surgical treatment13,14.

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Medial Elbow Pain in Overhead Athletes

There are several sports aside from baseball, including gymnastics, javelin throwing, wrestling, and football (quarterbacks and linemen), in which athletes can experience substantial medial elbow pain. Studies have shown that upper-extremity injuries account for >45% of injuries in National Collegiate Athletic Association (NCAA) baseball players, whereas elbow injuries, mostly medial, are the leading cause of missed game time of >10 days. Several medial elbow structures, including the common flexor mass, olecranon, trochlea, coronoid, and ulnar nerve (either from compression or instability) can cause pain and must be evaluated as the treatment options vary widely for these different structures.

The increase in UCL injuries as well as primary UCLRs, specifically in MLB pitchers, has been well documented15. Recent literature has also documented an increase in the number of revision UCLRs16. While the results following primary UCLR in MLB pitchers have been encouraging, the results following revision UCLR in these athletes have been disappointing and clearly inferior in comparison with those following primary UCLR16. Although the number of professional athletes undergoing UCLR is concerning, a more pressing issue is the increase in the number of UCLRs seen in high school athletes17. Large prospective studies have identified multiple risk factors for elbow injuries in pitchers, including high pitch counts, pitching >100 innings per year, pitching on consecutive days, pitching for multiple teams, pitching while fatigued, pitching with higher velocity, pitching with supraspinatus weakness, geography (pitching while growing up in warmer climates), pitching with a glenohumeral internal rotation deficit, and, most recently, pitching with a loss of total arc of motion18-24. Prevention programs have been instituted in an attempt to decrease injury rates by addressing these risk factors. These prevention programs include limiting the number of pitches that a pitcher can throw in a single game, mandating a period of rest between pitching outings, limiting the number of innings a player can pitch per season, and others. One interesting risk factor that will need more attention in the near future is core weakness25. Studies have recently identified core weakness as a potential cause for UCL injury, but, to our knowledge, no study has demonstrated the ability to decrease injury rates by improving core strength. Unfortunately, while numerous risk factors have been identified, these prevention programs have yet to be validated.

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Relevant Elbow Anatomy

The elbow joint is a complex hinge joint that is made up of 3 distinct articulations: the ulnotrochlear joint, the radiocapitellar joint, and the proximal radioulnar joint (PRUJ). The valgus carrying angle, typically between 11° and 16° (with higher angles in females than in males), allows the forearm and wrist to clear the hips during gait. Osseous restraints account for approximately 50% of elbow stability, and soft-tissue restraints account for the other 50%. The primary soft-tissue restraints to valgus force at the elbow are the flexor-pronator mass (specifically, the flexor carpi ulnaris [FCU]), UCL, and joint capsule. The UCL is composed of 3 distinct bundles (anterior, posterior, and transverse). The anterior bundle provides the majority of resistance to valgus stress at the elbow, the posterior bundle is a secondary stabilizer, and the transverse bundle does not cross the elbow joint. The anterior bundle originates at the anteroinferior aspect of the medial epicondyle of the humerus and inserts on the sublime tubercle and UCL ridge of the ulna. The sublime tubercle is approximately 5.5 mm distal to the articular surface. Just medial to this structure and extending distally is the UCL ridge, averaging 24.5 mm in length, onto which the UCL inserts26. The UCL originates from a 9.6-mm-wide area of the raised surface of the anteroinferior aspect of the medial epicondyle, occupying 67% of the width of the epicondyle. The 2 bands function in a reciprocal fashion, with the posterior band tight in higher degrees of flexion (≥90°) and the anterior band tight in lower degrees of flexion (<90°) (Fig. 2). Finally, the ulnar nerve, which lies posterior to the medial intermuscular septum before coursing around the medial epicondyle, is sensitive to both microtrauma and macrotrauma and is critical for hand function. The repetitive tensile and compressive forces that the ulnar nerve experiences during elbow flexion and valgus loading can lead to damage over time.

Ciccotti et al. used ultrasonography to demonstrate that the UCL undergoes hypertrophy with use, reporting that the mean thickness of the UCL was significantly greater in the throwing arm than in the non-throwing arm (mean [and standard deviation], 6.2 ± 1.6 mm compared with 4.8 ± 1.3 mm; p < 0.001)27. This hypertrophy of the ligament was accompanied by increased laxity, with ultrasonography demonstrating a mean medial gap of 4.56 mm in the throwing elbow as compared with 3.7 mm in the non-throwing elbow (p < 0.02)27. The laxity and gapping are likely adaptive, providing strength to tolerate high valgus stress while allowing the generation of higher pitching velocities.

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Evaluation of Medial Elbow Pain in the Throwing Athlete

The initial evaluation of an athlete with medial elbow pain begins with a thorough history, including the duration of symptoms and when during the pitching cycle the symptoms occur. Pitchers often complain of vague elbow pain along with a decrease in velocity and a loss of control over time. Rarely, pitchers will state that the arm felt completely normal until a specific pitch was thrown, during which they felt a pop in the elbow13. Ulnar nerve symptoms such as numbness and/or tingling in the small finger and the ulnar side of the ring finger must be discussed, as should prior treatments, both surgical and nonsurgical.

The physical examination begins with the trunk and arms completely exposed, with modesty preserved in female athletes. The exposed region is inspected for swelling, scars, skin lesions, muscle atrophy of the elbow and hand, and deformities such as prominent posterior osteophytes or an abnormal carrying angle. Palpation of the medial epicondyle, flexor pronator mass, sublime tubercle, and olecranon is performed to assess for tenderness. The presence or absence of the palmaris longus tendon should be recorded for both arms. The throwing arm is then taken through active and passive range-of-motion testing of the elbow and forearm as well as abduction and forward elevation at the shoulder to assess for scapular dyskinesis or glenohumeral internal rotation deficit. Posterior osteophytes often lead to mild elbow flexion contractures and pain at terminal extension. During elbow range of motion, stability and irritability of the ulnar nerve are evaluated as dysfunction or neuritis of the ulnar nerve can cause medial elbow pain. A full neurovascular examination is performed, including motor and sensory testing of the ulnar nerve. Furthermore, to rule out other sources of medial elbow pain such medial epicondylitis, tears of the flexor-pronator mass, and valgus extension overload, resisted forearm pronation and forced elbow extension maneuvers are performed. Special tests are then employed to assess the UCL (Figs. 3-A through 3-F).

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Imaging

High-quality anteroposterior, lateral, and oblique radiographs of the elbow, although often showing normal findings, are necessary to look for calcifications within the ligament, ligamentous avulsions, capitellar osteochondral defects, persistent physes, and osteophytes. A difference of 1 to 3 mm between elbows on stress radiographs can indicate a UCL injury, although pitchers can have increased medial laxity of the pitching elbow as compared with the non-pitching elbow, so these results can be difficult to interpret27. The best way to visualize both full and partial-thickness UCL tears as well as concomitant elbow abnormalities is with use of magnetic resonance imaging (MRI) or MR arthrography (MRA)28. MRA has been shown to be substantially more accurate than MRI for the diagnosis of UCL tears (sensitivity and specificity, 92% and 100%, respectively, compared with 57% and 100%, respectively)28. The typical appearance of an intact UCL is a low signal on T1-weighted images, whereas a tear of the UCL, most commonly seen at the medial epicondyle, will show edema within the ligament and as such will be bright on T2-weighted images29-31.

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Treatment

The goals of treatment of UCL injuries include (1) restoration of elbow stability, (2) reduction of elbow pain, and (3) return to the pre-injury level of play. In some patients, these goals can be achieved with nonoperative modalities, and thus all patients initially should be managed nonoperatively. In other patients, operative intervention may be necessary to achieve these goals.

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Nonoperative Treatment Options

There are limited data on outcomes following the nonoperative treatment of UCL injuries. Rettig et al., in a study of 31 athletes who were managed with 3 months of rest followed by 3 months of strengthening, rehabilitation, and return to throwing, found a 42% return-to-sport rate32. That study did not evaluate whether the return to sport was to the same level as before the onset of symptoms. Platelet-rich plasma (PRP), while still new and controversial, is another potential nonoperative treatment option for patients with UCL tears. Moraes et al., in a recent systematic review, reported that there was insufficient evidence to conclude that PRP was beneficial. Furthermore, they were unable to elucidate the most effective PRP preparation for the treatment of ligament injuries33. Podesta et al., in a study of 34 partial-thickness UCL tears that were treated with PRP coupled with structured rehabilitation, reported an 88% return-to-sport rate at an average of 70 weeks of follow-up29. Because that study lacked a control group, it is not clear whether the results were due to PRP or simply to rest and rehabilitation. Furthermore, the study demonstrated evidence suggesting that PRP treatment led to a reduction in laxity of the injured UCL, or a tightening of the ligament on dynamic examination, which had not been described previously to our knowledge. Further collaborative studies are necessary to confirm those conclusions. While it remains unknown if PRP has some benefit for the treatment of UCL tears, evidence has shown that corticosteroid injections have negatively affected the healing of UCL tears in rabbit models, and, as a result, such injections are not recommended for the treatment of UCL injuries34.

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Operative Treatment

When a patient has had a failure of nonoperative treatment and still wishes to return to sport, has continued medial instability, or has a full-thickness UCL rupture on MRI scans, operative treatment can be offered. Operative intervention includes either repair or reconstruction of the UCL. While previous studies have shown inferior results of UCL repair compared with reconstruction, Savoie et al. reported a 97% return-to-sport rate and only a 6.7% failure rate in a study of 60 college and adolescent athletes who were managed with UCL repair14. All patients in that study had UCL injuries at either the proximal or distal end of the UCL as well as normal quality in the midportion of the UCL. As inferior results have been seen in studies without these strict inclusion criteria13, it seems that UCL repair may have a role in the properly selected patient.

Since the initial description of the UCL reconstruction technique by Jobe et al. in 1986, several modifications have been offered (Table I)2-12. The standard docking technique used by the senior author of this article will be described below in detail10. Each of these techniques is performed with the patient in the supine position and with use of an arm board, a tourniquet, and general and/or regional anesthesia.

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Docking Technique10

Although the original docking technique involved routine elbow arthroscopy prior to UCLR, we only perform elbow arthroscopy if concomitant pathology amenable to arthroscopic treatment is present. Prior to the incision, the medial epicondyle and the paths of the ulnar nerve and the native UCL are marked. A curvilinear incision is made posterior to the medial epicondyle, and the branches of the medial antebrachial cutaneous nerve are identified and protected. The 2 heads of the FCU are identified, and the ulnar nerve is found running between the heads of the FCU. The nerve is decompressed by meticulously relieving any areas of constriction. If there are no preoperative ulnar nerve symptoms, an FCU-splitting approach is used to expose the UCL. If the athlete experiences subjective symptoms related to the ulnar nerve, or if there are objective findings on physical examination, the surgical plan includes subcutaneous transposition of the ulnar nerve. In that situation, the technique described by Andrews and Timmerman can be used, with the nerve being transferred subcutaneously with use of a fascial sling3. The origin of the FCU is sharply peeled off of the medial epicondyle from posterior to anterior until the humeral attachment of the UCL is clearly visualized, without complete detachment of the flexor-pronator origin. When the muscle-splitting approach is used, the sublime tubercle is palpated and the FCU is split in line with its fibers to expose the insertion of the UCL. This splitting of the muscle allows for visualization of the sublime tubercle, the medial epicondyle attachment, and the native UCL. A longitudinal split is then made in the UCL and joint capsule, and medial gapping is evaluated with a valgus load. A UCLR-specific system with drill guides facilitates consistent tunnel creation for both the ulna and the humerus, although many surgeons perform the procedure without guides. The ulnar tunnel is drilled with use of a 3.5-mm drill-bit and a 55° V-shaped drilling guide (Arthrex) that is placed parallel to the articular surface on either side of the sublime tubercle (Fig. 4); alternatively, a burr or drill without a guide can be used to create the tunnel. The anterior and posterior limbs of the tunnel are drilled with use of the guide, which is designed to converge the tunnels with a minimum 1-cm bone bridge of the ulnar cortex. A curved curet is then used to smooth out the tunnels to prevent damage to the graft. The graft is prepared on one end with use of a heavy #2 high-strength suture, and this suture, followed by the graft, is passed through the ulnar tunnel via a suture passing wire. Sterile mineral oil can ease graft passage.

A 4.5-mm drill-bit is used to drill a 15-mm unicortical socket on the face of the medial epicondyle, centered at the anatomical attachment point of the UCL. Again, a curet is used to smooth the edges of the socket. A variable-angle humeral drill guide is used to drill 2 proximal 2.0-mm suture holes that converge in the previously drilled socket with at least a 5-mm bone bridge (although a 10-mm bone bridge is preferred) (Fig. 4). A suture-passing device is then used to pass the sutures out the smaller tunnels. One limb of the graft is docked into the humeral tunnel by gently feeding it into the socket and pulling the suture out one of the tunnels. The length of the second limb of the graft is measured and then is cut to a length that will allow 10 mm of graft to fit into the 15-mm socket in order to allow proper tensioning. The sutures from this end of the graft are then passed out the other humeral tunnel. The elbow is flexed to either 30° or 90° (recent evidence has shown no difference in load to failure based on elbow flexion during graft fixation35), the arm is placed in supination with a varus force applied to the elbow, and then the initial incision in the native UCL is closed with nonabsorbable suture. The elbow is cycled 15 times to remove any slack in the tendon, and then the sutures from the tendon are tied under maximum tension. The graft should remain isometric throughout the arc of elbow motion. The limbs of the graft can be sewed to one another and/or to the native UCL for added support (Fig. 5).

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Elbow Arthroscopy

Elbow arthroscopy theoretically can be added to any technique, although it was not routinely used until the introduction of the docking technique. Elbow arthroscopy is typically performed first, looking from a lateral portal in the anterior compartment for loose bodies and cartilage damage. A valgus stress test can be performed to evaluate for valgus laxity (if the joint gaps open >3 mm, then a UCL tear is present). Usually, an examination of the posterior compartment is also performed to examine for loose bodies or osteophytes.

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Ulnar Nerve

While some techniques include transposition of the ulnar nerve as a routine part of the UCLR, in most techniques this decision is based on the presence of preoperative symptoms (numbness in the fingers, wasting of the first dorsal interosseous muscle, a subluxating ulnar nerve, etc.). No preoperative electrodiagnostic testing is required. We are not aware of any compelling data for or against routine ulnar nerve transposition. When indicated on the basis of symptoms and clinical examination, we perform a subcutaneous ulnar nerve transposition in the setting of a primary UCLR.

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Graft Options

Although several graft options are available, the most common of which is the palmaris longus tendon, previous studies have not demonstrated clinical superiority of any one type of graft17,36. Furthermore, biomechanical studies have shown that graft diameter does not correlate with elbow valgus stability37. The palmaris longus tendon can be harvested via a small incision just proximal to the proximal wrist flexion crease by transecting the tendon distally and using a tendon harvester aimed toward the medial epicondyle to strip the tendon from its attached muscle. Care must be taken to ensure that the median nerve is not confused with the palmaris longus. Other viable graft options for UCLR (in addition to palmaris longus autograft) include gracilis or semitendinosus autograft, toe extensor autograft, plantaris autograft, patellar tendon autograft, Achilles autograft, and allograft tendons5,17,36.

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Concomitant Procedures

Although the UCL is often injured in isolation, the physician should evaluate for concomitant injuries. If concomitant trochlear chondromalacia, loose bodies, or olecranon osteophytes are present and symptomatic, they can be addressed arthroscopically. Azar et al., in a recent retrospective series of 91 UCLRs, reported that 27 patients (30%) underwent concomitant procedures, of which 22 (81%) were posteromedial osteophyte excisions38. Of the 67 patients who were available for follow-up, 53 (79%) had successful outcomes. The treating surgeon should not be overly aggressive when excising posteromedial osteophytes as this can destabilize the elbow and lead to an increase in valgus instability. Osbahr et al. found that baseball pitchers who underwent UCLR with concomitant debridement or microfracture for the treatment of posteromedial chondromalacia had a lower return-to-sport rate (76%) compared with historical controls39. Finally, at this time, the use of biological augmentation (PRP, dermal allograft, and mesenchymal stem cells) has not been proven to improve healing following UCLR, although case reports have shown encouraging results40.

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Postoperative Rehabilitation and Timing of Return to Sport

A variety of rehabilitation programs have been described. Generally, each program consists of 4 individual stages (Table II)41. The time spent in each stage is variable and should be tailored to the individual athlete. In the first postoperative phase, many surgeons use a hinged elbow brace and limit full extension for 2 to 4 weeks. Return to throwing activities typically begins around 4 months, but throwing from a mound is not resumed until 6 months or later. We are not aware of any study that has compared different time frames for allowing the athlete to return to sport, so blanket recommendations on the timing of return to sport cannot be made. As the mean time to return to the same level of sport is >1 year15, there does not seem to be a compelling reason to pursue an accelerated rehabilitation process with the current methods of UCL reconstruction. Return to full competition should be determined on an individual basis and can routinely take anywhere from 10 to 18 months15.

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Surgical Outcomes

Table III summarizes the surgical outcomes following UCLR4,5,12,17,36,42-46. Since the introduction of “Tommy John surgery,” there have been numerous outcome studies on baseball pitchers15, javelin throwers43, National Football League (NFL) quarterbacks47, and other athletes that have demonstrated a reliable return-to-sport rate of ≥80%4,15,38,44. Revision UCLR offers less-predictable results, with a 40% to 65.5% rate of return to sport16,48. However, the percentage of pitchers who return to the previous level of performance and not simply to baseball may be even lower16. Furthermore, despite a growing public perception that pitchers who undergo UCLR increase their pitching velocity following surgery, studies have shown that this perception of an increased velocity is not true49,50. Jiang and Leland, in a study of 38 MLB pitchers, found that pitchers either maintained the same velocity on their fastball and change-up pitches following UCLR or, more commonly, lost a small but significant (p < 0.05) amount of velocity50.

There is still a paucity of literature surrounding treatment of the ulnar nerve, the need for arthroscopy, and the ideal timing of the 4 phases of rehabilitation and return-to-sport protocols in these patients. Unfortunately, the majority of evidence surrounding UCLR involves Level-IV case series or reviews of professional players12,14,44. Several recent contributions to the UCLR literature came in the form of biomechanical studies comparing various graft choice, tunnel drilling, and fixation methodologies7,9,37,51,52. While these were laboratory studies and the results may or may not be transferable to athletes, the studies have shown no superior surgical technique or graft choice in biomechanical testing. Two systematic reviews, one by Vitale and Ahmad and one by Watson et al., attempted to compare return-to-sport rates and results across various UCLR techniques53,54. Vitale and Ahmad found better outcomes for patients who were managed with a muscle-splitting approach. They also noted a lower rate of ulnar neurapraxia (4% versus 9%) in patients managed without obligatory ulnar-nerve transposition (only transposed for preoperative symptoms) than in those who had the ulnar nerve transposed regardless of preoperative symptoms53. Similarly, Watson et al. found a higher return-to-sport rate and a lower complication rate in patients who underwent UCLR with use of the docking technique54.

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Complications

Complication rates following UCLR have been reported to range from 3% to 40%38,48. The most common complication following UCLR is ulnar neuropathy (even if ulnar nerve symptoms were not present preoperatively), with the reported rate ranging from 3% (docking technique) to 26% (original Jobe technique)13,53. Other complications include problems at the graft-harvest site (4%)38, synovitis (7%)48, stiffness (13%)48, and reoperation (2%)38.

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Overview

Ulnar collateral ligament injuries are increasing in high school, collegiate, and professional athletes. Nonoperative treatment is recommended for the initial treatment of partial UCL tears, and there may be a role for biological augmentation of the healing process. When symptoms persist and the athlete is unable to return to sport at the desired level, good, reliable results can be obtained following operative reconstruction of the UCL with use of a well-fixed tendon graft in a relatively isometric position. Postoperative rehabilitation protocols are variable, but return to throwing occurs by 6 months and return to competitive sports is likely to take 1 year or longer.

Investigation performed at Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois

Disclosure: The authors indicated that no external funding was received for any aspect of this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work and “yes” to indicate that the author had a patent and/or copyright, planned, pending, or issued, broadly relevant to this work.

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