Risk Factors Leading to UCL Reconstruction and Revision Surgery: A Case Report of a Division I Collegiate Pitcher

Transcription

1 Skyline - The Big Sky Undergraduate Journal Volume 2 Issue 1 Article Risk Factors Leading to UCL Reconstruction and Revision Surgery: A Case Report of a Division I Collegiate Pitcher Taylor M. Bennett Northern Arizona University, tmb246@nau.edu Follow this and additional works at: Part of the Medicine and Health Sciences Commons Recommended Citation Bennett, Taylor M. (2014) "Risk Factors Leading to UCL Reconstruction and Revision Surgery: A Case Report of a Division I Collegiate Pitcher," Skyline - The Big Sky Undergraduate Journal: Vol. 2 : Iss. 1, Article 2. Available at: This Research Article is brought to you for free and open access by Skyline - The Big Sky Undergraduate Journal. It has been accepted for inclusion in Skyline - The Big Sky Undergraduate Journal by an authorized editor of Skyline - The Big Sky Undergraduate Journal.

2 Risk Factors Leading to UCL Reconstruction and Revision Surgery: A Case Report of a Division I Collegiate Pitcher Keywords UCL, Elbow Injury, Throwing Injury, Baseball, Tommy John, Tommy John Surgery, Reconstruction, Elbow Surgery, Risk Factors This research article is available in Skyline - The Big Sky Undergraduate Journal:

3 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report Introduction The ulnar collateral ligament (UCL) of the elbow is the principal stabilizing structure that acts to oppose valgus stress on the elbow. 1-5 Injury to the UCL is a result of valgus overload seen almost exclusively in overhead throwing sports such as baseball, softball, football, tennis and javelin. 5 Chronic dysfunction and acute rupture of the UCL is attributed to tensile overload resulting in microtrauma and repetitive joint attenuation. 5 Pain, tightness, and instability are most notable between the late cocking phase and early acceleration phase of the throwing motion. 4 In a study by Cain et al. 98% of patients who underwent UCL reconstruction (UCLR) were male; 95% participated in baseball, 32% played professionally, 48% played collegiately, and the remaining 20% played at the high school or recreational level. 8 Of these baseball players 90% were pitchers and the average patient was 21.5 years of age. 8 This report will be focused primarily on the baseball pitcher, due to the large influence of the baseball population and its pitchers. A growing trend in the number of UCLR procedures has been observed. Cain et al. also noted a significant increase in the number of procedures done in their clinic; nearly 500 from to nearly 800 between the years of Similarly, Petty et al. reported an increase in UCLR procedures performed; 85 from to 609 from with a 50% increase among high school baseball players. 9 A possible complication with any procedure that utilizes a tendon graft is graft failure. Graft failure following UCLR has only been reported in 1% of cases. 10 As the number of primary reconstructions increases the number of revision reconstructions increases. Jones et al. observed that 18 MLB pitchers underwent UCLR revision over a 14 year period with 14 of those procedures occurring over the second half of the time period. 10 This trend and the factors involved in graft failure and the need for a revision UCLR will be analyzed for an individual case involving a division I baseball player. The main objective is to highlight the contributing factors that led to this individual case so that those who assess, rehabilitate, and seek to prevent UCL injuries in baseball players across all levels of competition can identify them. Functional Anatomy The UCL is a triangular ligamentous complex located at the medial elbow and is comprised of three bundles: the transverse, posterior oblique, and the anterior oblique bundles. 5, 11 Figure 1 (Appendix A) illustrates the UCL complex. The anterior oblique bundle originates at the medial epicondyle of the humerus Published by Skyline - The Big Sky Undergraduate Journal,

4 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 and inserts on the medial aspect of the coranoid process of the ulna. 5, 11 The anterior bundle serves as the chief valgus restraint from of elbow flexion. 5 The transverse bundle originates from the medial olecranon process of the ulna and inserts onto the infero-medial portion of the coranoid process of the ulna. 5, 11 The transverse bundle plays no role in the resistance of valgus forces about the elbow. Lastly, the posterior oblique bundle is a fan shaped extension of the joint capsule that runs vertically from the medial epicondyle to its insertion on the medial border of the trochlear notch of the ulna. 5 The posterior oblique bundle resists valgus stress at 90 of elbow flexion. 5 The forearm musculature is also important as it plays an integral role in the dynamic stabilization of the humero-ulnar joint. The forearm musculature also controls positioning of the hand and forearm during the throwing motion. In addition, the flexor-pronator mass acts to counteract valgus force on the UCL by providing an opposing varus force. 12 The flexor-pronator mass and its components that support the medial elbow and UCL will only be reviewed. These muscles are the pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, and the flexor digitorum superficialis. The common point of origin at the medial epicondyle of the humerus allows the flexor-pronator mass to counteract valgus force. Biomechanics The overhead throwing motion (Appendix A, Figure 2) can be described as a transfer of kinetic energy from the lower extremity through the trunk to the shoulder and elbow and finally to the hand as a result of linear and angular velocity, acceleration, and torque. 13, 15 The six phases of the throwing motion are the wind-up, stride, arm cocking, acceleration and deceleration phases, ending with the follow-through. 13 UCL torque and activation is at its highest during the early cocking phase through the acceleration phase and reaches peak varus torque 13, 14 and valgus stress between the late cocking and early acceleration phases. The average valgus stress generated by a pitch from an adult overhead throwing athlete is 64 N.m. 12 This force is equivalent to the weight of 150 baseballs. 12 The anterior band of the UCL provides approximately half of the varus counter-torque when the elbow is flexed to 90 and provides even greater restraint when flexed greater than On average, each pitch thrown approaches the tensile threshold of the UCL which is approximately 33 N.m. 12, 13 In elite throwers total elbow valgus torque has been recorded at 120 N.m. 13 Tensile overload of the UCL is the primary cause of acute rupture and chronic ligament attenuation. 10 Tensile overload occurs when valgus stress is greater than the varus counter-torque provided by the dynamic stabilizers of the elbow. These stabilizers include the UCL, flexor-pronator mass, triceps, and glenohumeral (GH) internal rotation (IR) 2

5 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report of the shoulder. 12 Recent studies have shown that a combination of shoulder IR and pronation of the forearm during deceleration and follow-through achieves varus 12, 13, 16 acceleration resulting in valgus unloading of the UCL. Diagnosis Diagnosis of acute UCL rupture or chronic ligament attenuation should be executed as a multifaceted approach comprised of a thorough history, physical examination and imaging studies. Cain et al. reported that 53% of subjects were classified under the chronic UCL injury category while 47% were categorized as having sustained acute UCL trauma. Seventy-three percent of these patients reported that onset of symptoms occurred while participating in a game. 8 The most common symptom reported by throwers with UCL injury is pain 1, 4, 5, 6, between the late cocking and early acceleration phase of the throwing motion. 8, 17 Many throwers who exhibit chronic pain and instability also report a decrease in velocity and a subsequent loss of control when throwing. 5, 17 Individuals who have had an acute rupture often times report a popping sensation, followed by sharp pain in the medial elbow after an individual throw and cannot continue throwing. 5, 17 Numbness and tingling in the forearm and 4 th and 5 th digits are also frequently reported after acute UCL rupture due to ulnar nerve compression. 17 The history portion of the exam should document the patient s dominant hand, throwing style, accuracy, workload, and occurrence of symptoms. 5 If the injured party is a pitcher the examiner should also obtain information regarding pitch type, workload, and pitches that reproduce symptoms. 5 Conversely, individuals who are found to have chronic valgus instability and potential UCL injury will present with symptoms of medial elbow pain, soreness, and tightness while throwing for an extended time-frame. 1-8 These symptoms are often managed with conservative treatment. Overuse is the number one factor associated with UCL injury. 9 Those with chronic instability who do not respond favorably to conservative treatment will present with symptoms that continue to worsen as activity continues. 4, 9 The findings of the physical examination of the UCL are obtained through a series of structural tests that compare the pain and laxity experienced in the injured elbow to the non-injured elbow. When acute rupture or chronic attenuation is present the examiner will note point tenderness approximately 2 cm distal to the medial epicondyle. 5, 6 Also, joint gapping can be felt in some cases of complete rupture when valgus force is applied to the elbow. It is also important during physical examination to assess the ROM and function of the shoulder and scapula. 3, 5, 14, 19, 20 An injury or imbalance of these structures can cause or predispose the patient to further UCL damage. 3, 5, 14, 19, 20 Identification of the palmaris longus Published by Skyline - The Big Sky Undergraduate Journal,

6 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 tendon is critical to report to the surgeon as it is the most frequently used graft during UCLR. 6 Structural evaluation of the UCL complex is done by performing multiple special tests in combination with imaging studies. 4-6 These tests are the valgus stress test, modified milking maneuver, and moving valgus test (Appendix, Figures 3-5). These tests aim to recreate the reported symptoms of pain and instability. Joint laxity is considered a secondary marker as it has proved inconsistent due the minimal amount of gapping that occurs at the humero-ulnar joint. 9 Detection of valgus instability through physical examination is often difficult to quantify as many throwers have increased valgus laxity of the nondominant arm as 5, 18 well. Evaluation of the shoulder for glenohumeral internal rotation deficit (GIRD), dyskinesis of the scapula, and rotator cuff strength are an integral part of assessment of determining the condition of the throwing elbow. 18 Assessment of core stability and strength as well as hip rotation values is necessary as dysfunction from any of these categories have been shown to affect the health and stability of the throwing elbow. 14 Fifty to ninety-four percent of patients across multiple studies that have sustained an elbow injury have exhibited problems with the scapula, rotator cuff, core stability and strength, as well as hip rotation. 20 Imaging Studies 5, 15, 16, 18, 19, Chronic UCL injury can be noted through radiographs due to the presence of loose bodies, ossification of the ligament, as well as osteophytes around the olecranon process. 22 An associated trend between ossification of the UCL and partial and full thickness tears has been noted. 23 Valgus stress radiographs may be used to assess medial joint line gapping. 22, 24 Azar et al. reported that 46% of their athletes who had UCLR had positive preoperative valgus stress radiographs. 26 Thompson et al. reported that 88% of their athletes prior to UCLR presented with joint opening to valgus stress that was 2mm greater than the uninjured elbow. 27 MRI has been reported as 57% to 79% sensitive and 100% specific for UCL tears. 28 UCL injury may present on a MRI as laxity, irregularity, reduced definition, and increased signal within and around the ligament as a result of edema. Contrast MRI or MR arthrography with intra-articular gadolinium has been reported to have 97% sensitivity and 100% specificity for UCL tears. Due to its diagnostic accuracy the MR arthrogram with contrast has become the gold standard diagnostic tool for identifying acute and undersurface UCL tears after plain radiographs are obtained. 5, 18, 22 In cases of chronic UCL injury MR 4

7 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report arthrography is much less effective because dye leakage that is seen in acute ligament tear is often not present. 5 (Appendix A, Figures 3 & 4) A study by Dodson et al. established 3 criteria for selecting athletes with UCL injury for surgery: (1) Positive MRI or MR arthrogram that suggests UCL injury; (2) A history of medial elbow pain in proximity to the UCL that occurs during the late cocking phase through the acceleration phase of the throwing motion; and (3) pain that is severe enough that it prevents the athlete from participating in competition. 1 Reconstruction Techniques The first UCLR utilized a free tendon autograft configured in a figure-of-8 pattern and anchored in bone tunnels located at the medial epicondyle and coronoid process. 6, 24 At that time the UCLR was considered a revolutionary procedure that allowed throwers to return from a career ending injury. The first study published by Jobe et al. reviewed UCLR in 16 cases and reported a 63% rate of return to pre-injury level. Numerous modifications to the original UCLR procedure have since been implemented, including the modified Jobe technique, the docking technique, the modified docking technique, and interference screw fixation (Appendix A, figures 5-7). 6 These modifications have resulted in improved 1, 6, 8, patient outcomes with some studies reporting a 90% return to play (RTP) rate. Watson et al. conducted the largest review of UCLR techniques to date which was comprised of 1368 patients across 21 studies (Appendix B, table 1). 6 Seventy-eight percent of the patients in this study were collegiate or professional athletes. 6 This study analyzed the number of patients per technique, graft used, post-operative complication rates, and RTP statistics. The technique with the highest patient number was the modified Jobe technique at 78% (1064/1368). 6 Complication rate was 19% across all studies, with the Jobe technique (30%) and the modified Jobe technique (19%) exhibiting significantly larger complication rates than the other techniques (Appendix B, Table 2). 6 Graft failure with subsequent revision surgery occurred in only 1% of all 1368 patients. The technique associated with the largest number of revision surgeries was the modified Jobe technique with nine. 6 Fifty-five percent of patients had an ipsilateral palmaris longus autograft, while 24% had a gracilis autograft and 11% of patients had a contralateral palmaris longus autograft. 6 Other grafts, primarily the gracilis autograft, may be utilized in the rare instance when the palmaris longus is not present in the patient. Published by Skyline - The Big Sky Undergraduate Journal,

8 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 The overall RTP rate was reported at 79%. 6 Interference screw fixation, modified docking, and docking techniques reported RTP rates above or equal to 90%. The modified Jobe technique reported a RTP rate of 78%. Another large review reported that the average RTP time in 743 was 11.6 months (Appendix B, Table 3). 8 Revision Reconstruction Multiple studies have noted that approximately 1% of all UCLR procedures result in the need for revision. 3, 8, 10 Jones et al observed that 18 MLB pitchers underwent UCLR revision over a 14 year period with 14 of those procedures occurring over the second half of the time period. 10 The cases of 15 pitchers who underwent UCLR revision were reviewed by Dines et al. 3 The same authors reported a significant decrease in RTP rate (33%) in comparison to the RTP rate of pitchers who underwent an initial UCLR (79%) and a complication rate of 40%, twice that of the norm. 3, 10 After returning to competition the tolerable workload of relief pitchers was half that of their pre-injury level and one third in starting pitchers. 3, 10 The decrease in workload is more than likely attributed to continuation of post-surgical complications including ulnar nerve neuritis and flexor-pronator mass tightness and pain. A scarcity of literature to dictate rehabilitation and treatment of these individuals exists, which results in speculation. 10 Rehabilitation Conservative or non-operative rehabilitation for the throwing athlete has become a highly debatable topic. Due to the high success rate of UCLR many physicians choose to forego conservative rehabilitation as it has shown poor results based on the RTP rates of throwing athletes. 1, 5, 12 Success of non-operative treatment has been documented to be 42% to 50% effective in returning throwing athletes back to pre-injury participation levels. 5, 12 This method of treatment is almost exclusively implemented for athletes exhibiting chronic UCL attenuation. Conservative treatment focuses on reduction of symptoms through varying modalities first, followed by restoration of strength and pain free ROM of the shoulder, elbow, forearm and wrist. 12 A progression through sport specific movements is then initiated. The initial restoration portion of treatment lasts approximately 3 months followed by an interval throwing program that lasts for 2 months. 12 The initial phase of rehabilitation (Phase I) lasts for 3 weeks and begins directly after surgery. 1, 5, 8 It is critical to restore full elbow ROM which should be accomplished by week 6. 5, 8 During the second phase (weeks 4-10), a progressive 6

9 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report isotonic strengthening program focusing on the scapular stabilizers, rotator cuff, and surrounding arm musculature is started. Shoulder ROM exercises and the thrower s ten exercise protocol should be initiated during phase II. 5 During the third phase (weeks 10-16) advanced strengthening and sport and position specific rehabilitation exercises should begin. Restoration of shoulder internal and external rotation is paramount to allow the throwing athlete to successfully progress to and through advanced sport and position specific movement exercises. 1, 5, 8 At the 12 th week, the athlete can start an isotonic lifting program which includes bench press, seated rowing, lat pull downs, triceps push downs, and biceps curls, while continuing to perform exercises that accentuate sport-specific movements. 1, 5, 8 The throwing athlete begins a 2-handed plyometric throwing series at 12 weeks, and a 1-handed plyometric throwing program at the start of the 14 th week. Total body conditioning, core stability and lower extremity strengthening exercises should be emphasized throughout phase III. Starting at week 16 (Phase IV), an interval throwing program is initiated. 5, 8, 17 The timeline through the throwing program for position players is abbreviated as pitchers have higher physical demands and throw volume. The throwing progression should be performed 3-4 times weekly up to 10 months after surgery. 8 At the 8 month mark the pitcher should then begin light throwing off the mound. 8, 17 The pitcher should ultimately progress to up and down bullpens with variable rest between sets of pitches at the 10 month mark. After the 10 th month the athlete should begin a gradual integration into team activities. Athletic trainers, physical therapists, or doctors should make adjustments to this progression as needed based on any physical findings and recurrence of symptoms. Case Study A 23 year old male who is a right-handed baseball pitcher at a division I (DI) university underwent UCL reconstruction and UCLR revision within a 2 year timeframe. The patient stated that he has been playing baseball for 19 years and pitching since age 10. He has previous history of medial elbow pain that started at age 10 and recurred intermittently from age 12 to 16. At age 16, an MRI was performed to assess the structures of his throwing elbow with no positive findings reported. At age 16, he began preventative maintenance of the shoulder and forearm musculature. The athlete s high school pitching workload was approximately 8 starts per season combined with intermittent throwing and bullpen sessions 2-3 times per week. He did not participate in competition his 11 th grade season due to persistent medial elbow pain and diagnosed flexor-pronator mass tendinitis. His pitching workload increased during his 12 th grade season as he started 10 games. It is notable that at the end of his 12 th grade season he pitched 11 consecutive innings in one day over the span of two games, throwing 174 total pitches. He lists his pitches as a fastball, change-up, curveball, and slider. The athlete reported that his Published by Skyline - The Big Sky Undergraduate Journal,

10 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 highest recorded fastball velocity to date was approximately 93 mph. He began throwing the curveball at age 12. He did not begin throwing the slider until age 16, and did not begin throwing the change-up until he reached college at age 18. At age 19 while warming up for his first collegiate starting appearance he felt a pop followed by sharp, burning pain in his throwing elbow. His immediate symptoms of localized pain and edema were managed and ROM restoration was initiated prior to referral to the team physician. Non-contrast MRI was ordered by the physician, who noted a partial thickness tear with calcification and thickening of the UCL. Stress radiographs were ordered and returned a positive diagnosis of 2.5 mm medial elbow joint opening. The valgus stress test, modified milking maneuver, and moving valgus stress test were each positive. Elbow and forearm ranges of motion were within normal limits (WNL). Shoulder ROM was WNL except for internal rotation, which produced values of 57 in the left shoulder compared to 30 in the right shoulder. This deficit of 27 was noted and reported as abnormal. The athlete was then referred to a surgeon who specialized in UCLR. The athlete was scheduled for surgery in the summer of 2010, 1 month after the initial injury. The athlete underwent UCL reconstruction using the modified Jobe technique which was advised by his surgeon. This procedure utilized his left gracilis tendon for the UCL graft as he was identified as palmaris longus deficient. The surgeon confirmed thickening and degenerative changes to the anterior oblique bundle, consistent with chronic injury. The patient began rehabilitation 10 days after UCLR. The patient noted zero complications from the procedure and zero setbacks during the rehabilitative process. He completed the first 5 months of the standardized UCL rehabilitation protocol outlined previously, meeting all phase requirements and deadlines. Upon 3-month follow-up with the surgeon, the athlete was reassessed. There were no positive structural tests or recreation of previous symptoms. Strength and ROM were deemed as satisfactory. Upon 6- month follow-up, the surgeon noted that the athlete s progress was satisfactory for his current stage of rehabilitation. He noted minimal tenderness proximal to the medial epicondyle. All structural tests were negative and ROM and strength were WNL. Upon 12-month follow-up, the patient reported that at month 11 he was throwing and while attempting a throw of higher velocity felt notable pain and a small pop in his right medial elbow. Prior to his follow up, the athlete s symptoms were treated with rest and NSAIDs. Upon physical assessment, ROM was WNL, valgus laxity and the milking maneuver was negative. The positive moving valgus test was noted as mildly positive as mild discomfort was recreated. The physician ordered a MRI, and the report noted a focal signal over the UCL graft just distal to the humeral tunnel, where a small partial tear was seen. The athlete was treated conservatively and throwing was discontinued for 1 month to allow for resolution of symptoms per the physicians orders. Once resolution of symptoms occurred the athlete s throwing program was reinitiated at the beginning of the phase in which he reported symptoms. Care was taken to lengthen the last phases of the throwing 8

11 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report progression to allow for full restoration of throwing arm strength. The athlete was cleared 14 months after initial UCLR and did not throw in an NCAA sanctioned game until 20 months post-surgery. Once cleared, the athlete continued the thrower s ten program to maintain proper upper extremity strength and stabilization. The athlete changed institutions during this time and began pitching for another collegiate team. He pitched dually as a starting and relief pitcher for 9 months (70 appearances) ranging from between.2-8 innings. He pitched for his collegiate team and his summer travel team during this time. The athlete stated that this number of appearances was the highest work volume he had experienced in his baseball career. Twenty-five months after UCLR, the athlete stated that he was throwing a simulated game in the bullpen and felt a pop, followed by sharp pain, tingling in his forearm and hand, as well as subsequent edema. He was referred to the physician who performed his previous UCLR and a non-contrast MRI was ordered followed by physical examination. The MRI reported a new, full thickness graft rupture near the location of the previously mentioned partial tear. Examination of the injured elbow reproduced symptoms with all three structural tests. Flexorpronator strength was WNL as was elbow ROM. The athlete opted to discontinue baseball activities for 3 months adopting a regimen of rest from throwing and nonoperative rehabilitation. After three months, the athlete opted to undergo UCLR revision. The same procedure as the initial UCLR was performed utilizing the ipsilateral gracilis tendon graft. Post-operative rehabilitation was started 10 days after surgery. Modifications were made to the rehabilitation timeline by lengthening phases III & IV to allow for a more gradual progression. The athlete was instructed not to throw until 5 months after surgery. Analysis of the athlete s pitching mechanics was done before the athlete transitioned to the pitching progression. This was done to identify poor technique or improper biomechanics present in the athlete s delivery. His athletic trainer and pitching coach identified three biomechanical adaptations during a pitching session. An open lead foot position was seen upon front foot contact. In addition, when throwing the slider a detectable change in the level of horizontal shoulder abduction was seen. Lastly, a decrease in hip rotation and stride length was observed when the athlete became fatigued. These poor mechanics were adjusted gradually throughout the pitching progression. He noted a decrease in post-throwing arm tightness and soreness. The athlete completed the pitching progression successfully without any issues and was cleared by the team physician and his surgeon after 18 months of rehabilitation. The team s pitching coach and the athletic trainer placed him on a 45 pitch limit during competition. He has since appeared in games and reports feeling near his pre-injury status. Discussion Published by Skyline - The Big Sky Undergraduate Journal,

12 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 The number one risk factor associated with UCL injury in overhead throwers is overuse. 1 Analysis of overuse in regard to its contribution in graft failure in this individual case was noticeable. The review of the athlete s case highlighted multiple instances of excessive pitching and workload. This more than likely contributed to the presence of medial elbow pain in the athlete starting at age 10. This chronic valgus overload was seen and supported by the various imaging studies performed as well as the initial reconstruction. The second instance of prolonged overuse was seen upon return to pitching following initial UCLR. The athlete pitched excessively and exceeded his pre-injury workloads within a relatively short time after returning to play. Normally, pitchers who return to play after UCL are put on an innings limit. This was not the case in this particular instance. What should also be noted is the fact that rest through a discontinuation of throwing was never reported. Petty et al. noted that pitchers who discontinued throwing for a total of 2 months were much less likely to sustain shoulder or elbow injuries as a result of throwing. 9 The second noticeable abnormality upon review of the athlete s case was the degree of shoulder internal rotation deficit between the dominant and nondominant shoulders. Such deficit is often a result of the excessive amounts of shoulder external rotation seen in overhead throwers as well as posterior joint capsule tightening. Multiple studies have reported that pitchers with GH internal rotation deficits were at greater risk for elbow injuries. 16, 20 This increased risk is primarily because GH internal rotation acts to oppose valgus force on the elbow. The risk factor increases as competition level rises due to the greater forces placed on the upper extremity by elite throwers. GH internal rotation deficit should be noted as a potential contributing factor for the need of the initial UCLR. This association should also promote assessment of shoulder strength and ROM values in cases of medial elbow pain and instability. Poor pitching mechanics were present in the case of this athlete. Lead foot opening upon ground contact, and decreased hip rotation and stride length were observed during moments of reported fatigue. These biomechanical markers have been noted in studies that analyzed similar mechanics in pitchers with UCL injury The common association related to these markers is the amount of GH horizontal abduction they create. These mechanical adaptations increase trunk rotation resulting in the trailing of the arm behind the accelerating trunk and torso. 13 This puts increased valgus stress on the medial elbow and stresses the anterior capsule of the shoulder and has been shown to predispose pitchers to medial elbow and anterior shoulder injury Once these mechanics were adjusted to satisfactory patterns the athlete reported a decrease in forearm tightness and soreness. One can hypothesize that this is a result of decreased valgus force on the UCL and flexor-pronator mass. With the high volume and intensity involved in 10

13 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report competitive pitching small mechanical flaws can greatly magnify the tensile forces placed on the UCL. Analysis of the effects on the throwing arm as a result of pitch selection has been conducted at length. 14, 15 The fastball has been reported to produce the greatest amount of varus torque. 14 The varus torque created when throwing the fastball at high velocities, 80 mph or greater, as well as the curveball and slider approaches the tensile load of the UCL The slider has been reported as the only pitch that has associated risk of valgus overload due to the combination of forearm supination and GH horizontal abduction. These factors combined increase varus torque on the UCL by an additional N.m. 14 The use of the slider at a young age by the case subject combined with a notable increase in GH horizontal abduction upon arm acceleration could have compounded the stress placed upon the elbow resulting in the report of adolescent medial elbow pain progressing into degenerative changes and ending with UCL rupture. In conclusion, the risk factors associated with UCL injury are wide in variety, thus further analysis should be done to establish a set of predictive factors to better identify throwers who are at risk for injury or re-injury. Based on the information provided through this case analysis it can be noted that the factors associated with UCLR and revision in this individual case were cumulative in nature. This accumulation of contributing factors resulted in chronic pain and instability at a young age followed by UCL rupture. Overuse and dysfunctional pitching mechanics were the primary risk factors identified to indicate the need of the case subject s revision procedure. If the growing trend of UCLR and UCLR revision is to be altered pitching volume and frequency guidelines should be established for adult throwers to reduce the risk for chronic overuse. Review of shoulder function and ROM as well as throwing mechanics should be considered in athletes who report medial elbow pain, instability, and report a high competitive workload. Published by Skyline - The Big Sky Undergraduate Journal,

14 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 Appendix A: Figure 1 5 Figure 2 8 Figure

15 Bennett: Risk Factors Leading to UCL Reconstruction and Revision: A Case Report Figure 4: 1 MR Arthrogram with gadolinium contrast Figure 5 5 Figure 7 5 Figure 6 5 Published by Skyline - The Big Sky Undergraduate Journal,

16 Skyline - The Big Sky Undergraduate Journal, Vol. 2 [2014], Iss. 1, Art. 2 Appendix B: Tables

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