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Ulnar Collateral Ligament Injury

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Other Names

  • Ulnar collateral ligament injury
  • Medial collateral ligament injury
  • Valgus Instability
  • UCL Disruption
  • UCL Attenuation


  • This page describes injuries to the Ulnar Collateral Ligament of the elbow
    • UCL injuries can be acute, chronic or acute-on-chronic


  • First described by Waris in 1946[1]


  • More common among junior high and college players than junior high[2]


  • UCL functions as the primary elbow stabilizer to valgus stress
  • Throwing and overhead athletes produce reptitive valgus stress
  • Forces generated are significant
    • UCL is thought to fail at 34 Newtons
    • 68 N in tennis player serve[3]
    • Baseball players can generate 64 N
  • Chronic traction forces can lead to
    • UCL thickening and hypetrophy
    • Enthesiophyte at the ulna insertion
    • Fatigue of the common flexor tendon
  • UCL tear patterns[4]
    • 87%: torn at the midsubstance
    • 10%: avulsed distally from the ulna
    • 3%: avulsed proximally from the medial epicondyle


  • Chronic overuse
    • Microtrauma from repetitive valgus stress
  • Acute
  • Iatrogenic
    • Associated with medial elbow surgeries


Associated Injuries

Risk Factors

  • General
    • Height[5]
    • Long limb
  • Sports
    • Any overhead sports
    • Baseball (especially pitchers)
      • Increased pitching velocity[6]
      • Increased pitch count[7][8]
    • Tennis
    • Water polo
    • Volleyball
    • Golf
    • Wrestling
    • Track and field (especially javelin)
    • Football (quarterback)

Differential Diagnosis

Clinical Features

  • History
    • Important to characterize the onset of symptoms: acute, subacute or chronic
    • It is critical to characterize athletes level of participation, hand dominance, sports played, positions etc
    • Inquire about throwing style, ball velocity before and after the onset of elbow pain, throwing accuracy and phase(s) of throwing in which symptoms occur, types of pitches, pitch count, number of innings pitched,
    • Baseball: Pain most commonly during late cocking phase[4]
    • Tennis: Pain most commonly when the ball hits the racket
  • Physical: Physical Exam Elbow
    • In acute injuries you may see swelling, bruising, tenderness
    • Tenderness over the UCL: 81% to 94% sensitivity, 22% specificity for UCL tears[9]
    • Shoulder range of motion should receive special attention as a Glenohumeral Internal Rotation Deficit is a risk factor for UCL injuries
  • Special Tests



  • Standard Radiograph Elbow
    • Frequently normal
    • May show avulsion fragment in acute injury
  • In chronic injuries, may see:
    • Ossification of the UCL
    • Loose bodies
    • Radiocapitellar and/or ulnohumeral osteophytes
  • Stress radiographs
    • Used to detect increased ulnohumeral gapping
    • Sensitivity ranges from 46% - 88%[10][12]
    • Gravity stress radiograph: AP radiograph with the patient supine, shoulder in maximum external rotation, forearm unsupported
    • Alternative technique: examiner applies a valgus load while the anteroposterior radiograph was obtained
    • There is a device that applies a uniform valgus stress may be used to obtain a stress radiograph
    • Manual and device stress views are not sufficiently sensitive for UCL injuries and not commonly used[10]
  • Comparison to non-dominant elbow may be helpful.
    • Joint space widening on stress radiographs > 0.5 mm in the affected elbow compared with the unaffected elbow indicated a significant partial tear or a complete tear of the UCL[13]
    • Athletes with widening less < 0.5 mm on stress radiographs compared with the normal elbow had a normal UCL or just a small tear that could be managed conservatively


  • Not routinely used
  • CT Arthrogram would be study of choice
    • CT Arthrogram is 71% - 86% sensitive, 91% specific for UCL tears[9]


Right elbow MRI with contrast showing distal UCL injury and extravasation of contrast, forming the so called "T sign" (red arrow)[14]
  • MRI without arthrogram: 57% - 79% sensitive, 100% specific for UCL tears[9]
  • Findings
    • Laxity
    • Irregularity
    • Poor definition
    • Increased signal intensity
  • MRI Arthrogram: 97% sensitive for UCL tears[10]
    • MRI Arthrogram considered gold standard for evaluating UCL injuries
  • Findings
    • Fluid extravasation
    • So called "T-sign"
  • Can also better evaluate other soft tissue injuries


  • Normal UCL: appears as compact fibrillar echotexture, hyperechoic between the medial epicondyle and proximal ulna
  • In throwing athletes, especially pitchers, more likely to appear hypoechoic foci and/or calcifications and have laxity with valgus stress[15]
  • UCL Sprain: May demonstrate thickening, decreased echogenicity of the ligament, and surrounding hypoechoic edema[16]
  • Torn UCL: appear abnormally hypoechogenic, anechoic, and the fibers appear disrupted[17]
  • Pre-injury joint space is widened 1 - 1.5 mm on valgus stress in athletes who eventually developed a UCL tear[18]


  • Viewed through anterolateral portal, most notably the AOL
  • Partial (1 to 2 mm) and and full thickeness tears (4 to 10 mm) of the AOL can be visualized[19]
  • Timmerman et al: all patients with valgus instability on arthroscopy had AOL tears and all patients without valgus instability had intact, normal AOL on surgical exploration[9]


  • Strain
  • Low grade partial tear
  • High grade partial tear
  • Complete tear




  • Indications
    • Complete Rupture
    • Failure of conservative therapy for partial tears
  • Technique
    • MCL anterior band ligament reconstruction

Rehab and Return to Play



  • Kerlan-Jobe Orthopaedic Clinic Overhead Athlete Shoulder and Elbow Score (KJOC score)
    • Used to evaluate performance in throwing athlete
    • Has been validated in athletes undergoing UCL reconstruction[20]
  • 2-phase Rehabilitation Protocol (Rettig et al)[21]
    • 42% of athletes able to return to pre-injury level of play at 24 months
    • Phase 1 (first 2-3 months)
      • No throwing, NSAIDs, icing for 10 minutes 4 times a day
      • Splint/brace at 90° at night and as needed for pain during the day,
      • Active and passive range of motion exercises for flexors and pronators
    • Phase 2 (3 months)
      • Discontinue the splint/brace
      • Begin progressive upper extremity strengthening program of all muscle groups
      • Begin a throwing progression
      • Use an Elbow Hyperextension Brace for throwing and lifting
  • Sport-Specific Biomechanical Corrections
    • Baseball pitchers
      • Modify mechanics to decrease degree of elbow stress
      • Improve: Late trunk rotation, reduced shoulder external rotation, increased elbow flexion, and overhand pitching[22]
      • Lower pitch count


  • Hariri et al Protocol[23]
    • Long term goal: maintain shoulder flexibility, strength (periscapular, rotator cuff, core)
    • Immediate postop: splint 70° to 90° of flexion at neutral forearm rotation
    • 10-day follow-up visit: splint is removed and active wrist, elbow, and shoulder range of motion exercises are initiated
      • Hinged elbow brace beginning at 30° to 100°
      • Biomechanical study: full extension and flexion up to 50° with further flexion straining the reconstruction[24]
      • Range of motion is progressed such that there should be full range of motion by 6 weeks
    • 4 to 6 weeks: athlete is progressed to strengthening exercises that avoid elbow valgus stress.
    • 8 weeks: elbow brace is removed
    • 14 to 16 weeks: throwing program is initiated
    • Program is progressed such that the average pitcher returns to play at approximately 10 months.
      • Other positions or sports may return sooner

Return To Play

  • For sprains, low grade or high grade partial tears
    • May return to play after progressing through physical therapy pain free
  • For complete rupture
    • Needs to be cleared by surgeon
    • 82% of MLB pitchers return 18.5 months after Tommy John surgery without any major loss in output[25]


See Also



  1. Waris W. Elbow injuries in javelin throwers. Acta Chir Scand 1946;93:563–75.
  2. Han KJ, Kim YK, Lim SK, et al. The effect of physical characteristics and field position on the shoulder and elbow injuries of 490 baseball players: confirmation of diagnosis by magnetic resonance imaging. Clin J Sport Med 2009;19(4): 271–6.
  3. Elliott B, Fleisig G, Nicholls R, et al. Technique effects on upper limb loading in the tennis serve. J Sci Med Sport 2003;6(1):76–87.
  4. 4.0 4.1 Conway JE, Jobe FW, Glousman RE, et al. 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.
  5. Han KJ, Kim YK, Lim SK, et al. The effect of physical characteristics and field position on the shoulder and elbow injuries of 490 baseball players: confirmation of diagnosis by magnetic resonance imaging. Clin J Sport Med 2009;19(4): 271–6
  6. Bushnell BD, Anz AW, Noonan TJ, et al. Association of maximum pitch velocity and elbow injury in professional baseball pitchers. Am J Sports Med 2010;38(4):728–32.
  7. Lyman S, Fleisig GS, Andrews JR, et al. Effect of pitch type, pitch count, and pitching mechanics on risk of elbow and shoulder pain in youth baseball pitchers. Am J Sports Med 2002;30(4):463–8.
  8. Petty DH, Andrews JR, Fleisig GS, et al. Ulnar collateral ligament reconstruction in high school baseball players: clinical results and injury risk factors. Am J Sports Med 2004;32(5):1158–64.
  9. 9.0 9.1 9.2 9.3 Timmerman LA, Schwartz ML, Andrews JR. Preoperative evaluation of the ulnar collateral ligament by magnetic resonance imaging and computed tomography arthrography. Evaluation in 25 baseball players with surgical confirmation. Am J Sports Med 1994;22(1):26–31 [discussion: 32].
  10. 10.0 10.1 10.2 10.3 Azar FM, Andrews JR, Wilk KE, et al. Operative treatment of ulnar collateral ligament injuries of the elbow in athletes. Am J Sports Med 2000;28(1):16–23.
  11. Thompson WH, Jobe FW, Yocum LA, et al. Ulnar collateral ligament reconstruction in athletes: muscle-splitting approach without transposition of the ulnar nerve. J Shoulder Elbow Surg 2001;10(2):152–7
  12. Thompson WH, Jobe FW, Yocum LA, et al. Ulnar collateral ligament reconstruction in athletes: muscle-splitting approach without transposition of the ulnar nerve. J Shoulder Elbow Surg 2001;10(2):152–7.
  13. Rijke AM, Goitz HT, McCue FC, et al. Stress radiography of the medial elbow ligaments. Radiology 1994;191(1):213–6.
  14. Nicolette, Guy W., and Jocelyn R. Gravlee. "Ulnar collateral ligament injuries of the elbow in female division I collegiate gymnasts: a report of five cases." Open access journal of sports medicine 9 (2018): 183.
  15. Nazarian LN, McShane JM, Ciccotti MG, et al. Dynamic US of the anterior band of the ulnar collateral ligament of the elbow in asymptomatic major league baseball pitchers. Radiology 2003;227(1):149–54.
  16. . Miller TT, Adler RS, Friedman L. Sonography of injury of the ulnar collateral ligament of the elbow-initial experience. Skeletal Radiol 2004;33(7):386–91.
  17. Jacobson JA, Propeck T, Jamadar DA, et al. US of the anterior bundle of the ulnar collateral ligament: findings in five cadaver elbows with MR arthrographic and anatomic comparison–initial observations. Radiology 2003;227(2):561–6.
  18. Ciccotti MG. Dynamic ultrasound of UCL. Presented at the Herodicus Society annual meeting, April 24, 2008.
  19. Field LD, Altchek DW. Evaluation of the arthroscopic valgus instability test of the elbow. Am J Sports Med 1996;24(2):177–81.
  20. Domb BG, Davis JT, Alberta FG, et al. Clinical follow up of professional baseball players undergoing ulnar collateral ligament reconstruction using the new Kerlan-Jobe Orthopaedic Clinic Overhead Athlete Shoulder and Elbow Score (KJOC Score). Am J Sports Med 2010;38(8):1558–63.
  21. Rettig AC, Sherrill C, Snead DS, et al. Nonoperative treatment of ulnar collateral ligament injuries in throwing athletes. Am J Sports Med 2001;29(1):15–7.
  22. Aguinaldo AL, Chambers H. Correlation of throwing mechanics with elbow valgus load in adult baseball pitchers. Am J Sports Med 2009;37(10):2043–8. 42. Werner SL, Murray TA, Hawkins RJ, et al. Relationship between throwing
  23. Hariri, Sanaz, and Marc R. Safran. "Ulnar collateral ligament injury in the overhead athlete." Clinics in sports medicine 29.4 (2010): 619-644.
  24. Bernas GA, Ruberte Thiele RA, Kinnaman KA, et al. Defining safe rehabilitation for ulnar collateral ligament reconstruction of the elbow: a biomechanical study. Am J Sports Med 2009;37(12):2392–400.
  25. Gibson BW, Webner D, Huffman GR, et al. Ulnar collateral ligament reconstruction in major league baseball pitchers. Am J Sports Med 2007;35(4):575–81.
  26. Andrews JR. Complications of ulnar collateral ligament reconstruction. Presented at the International Society of Arthroscopy, Knee Surgery and Orthopedic Sports Medicine (ISAKOS). Florence (Italy), May 30, 2007
Created by:
John Kiel on 18 June 2019 01:54:00
Last edited:
31 October 2022 02:31:52