Shoulder Pain in the Throwing Athlete

Disease/Disorder

Definition

Pain and/or discomfort within the shoulder, proximal arm or shoulder girdle of the throwing arm, with associated symptoms that may include: “dead arm” sensation, loss of throwing velocity and/or control, and snapping or catching about the shoulder.

Etiology

• Shoulder pain in the overhead throwing athlete may be related to repetitive trauma (overuse),¹ biomechanical abnormalities and/or poor technique.
• Pain may be attributed to primary subacromial impingement or to shoulder instability with secondary subacromial impingement.
• In skeletally immature athletes, repetitive throwing can compromise the proximal humeral physis.
• Shoulder instability may be secondary to congenital hyperlaxity, acquired microinstability, or following traumatic dislocation.

Epidemiology including risk factors and primary prevention

Risk factors²

For a risk factor model of injury causality in adolescents please see: https://meridian.allenpress.com/view-large/figure/10573454/i1062-6050-54-10-1030-f01.tif

• Intrinsic
  • Age/Skeletal maturity
  • Height
  • Poor throwing mechanics
  • Previous shoulder injury
  • Previous spine or contralateral leg injuries
  • Glenohumeral (GH) laxity
    • Primary, or secondary to previous trauma
  • Weak rotator cuff musculature
  • Poor endurance or weak periscapular musculature
  • Throwing velocity
• Extrinsic
  • Early sports specialization
  • High volume of activity (pitches per game, months per year)
    • Playing with multiple teams at the same time
    • Playing multiple positions with high throwing volume
      • Playing as pitcher and catcher

Primary prevention¹

• Periscapular muscle strengthening
• Rotator cuff endurance and strengthening exercises
• Adequate dominant shoulder range of motion compared to the contralateral side.
• Core stability and spine mobility
• Proprioceptive training
  • Upper and lower extremities
• Appropriate body mechanics and adequate posture
  • Consider education by a throwing coach
• Rest from overhead activity (3-4 months per 12 months)
• Throwing volume monitoring (pitch counts, innings pitched, pitch velocity, pitching distance)³

Patho-anatomy/physiology

The shoulder has been compared to a “ball on a seal’s nose” with high degree of mobility and limited stability.⁴ The rotator cuff and deltoid elevate the arm maintaining the center of rotation and static stabilizers maintain GH stability at extreme ranges. In the young athlete, shoulder pain is usually the result of rotator cuff tendinopathy and instability, while in older throwers, pain may occur from degenerative changes, rotator cuff and/or glenoid labrum tears.

Peak forces may surpass 500 N-m and angular speeds of 7000 arc degrees/second.¹ Repeated stress leads to tensile overload of the proximal humeral physis and rotator cuff, attritional changes to the capsule and ligaments, and tears of the glenoid labrum.

The “Thrower’s Paradox” model¹ states that overhead throwing athletes must have enough shoulder flexibility to throw but maintain enough stability to prevent instability events from occurring. Thus, prevention of injury involves balancing shoulder flexibility and stability during training.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

New onset/acute

• Shoulder abduction/external rotation as seen in late cocking phase stresses the anterior capsular structures and posterior glenoid labrum. Superior migration of the humeral head may lead to subacromial impingement.
• Deceleration of the arm by the rotator cuff may lead to tensile overload of soft tissues.

Subacute

• Stress during the throwing cycle may cause an overload syndrome of the rotator cuff musculature, long head of the biceps tendon, superior labrum and proximal humeral physis.
• Weakness of the rotator cuff and scapular stabilizers and loss of shoulder internal rotation (IR) result from repetitive overhead activity.

Chronic

• Untreated, continued trauma to the shoulder stabilizers may result in tendinosis of the rotator cuff and/or long head biceps tendon, ligamentous laxity, capsular redundancy, microinstability and rotator cuff and labral tears.

Specific secondary or associated conditions and complications

• Subacromial bursitis
• Rotator cuff tendinopathy/tear
• Superior labrum anterior-posterior (SLAP) injury
• Posterior GH impingement
• Glenohumeral Internal Rotation Deficit (GIRD)
• Suprascapular neuropathy
• Quadrilateral space syndrome (involving the axillary nerve)
• Anterior capsular insufficiency
• Proximal or distal upper limb injuries

Essentials of Assessment

History

The overhead throwing athlete reports gradual onset of pain during activity, which progresses to pain at rest. There may be a history of high volume of activity, increasing velocity of pitches or previous injuries involving the shoulder or other body regions that were not rehabilitated. Pain may be associated to specific phases of throwing (cocking, acceleration and/or deceleration), “dead arm” sensation or change in performance.

Physical examination

Shoulder inspection may reveal scapular asymmetry and a dominant shoulder lower than the contralateral side. Range of motion testing usually shows increased external rotation (ER) and GIRD.¹ If there is a difference of more than 17 degrees of IR compared to ER, GIRD may be a cause of shoulder pain.  The total arc of motion (TRM) may predict throwing injury. TRM is measured by adding ER and IR at 90° of abduction. Side-to-side TRM should be within 5 degrees. If not, this may contribute to shoulder injuries in overhead throwers.⁵   Manual muscle testing reveals weakness of the external rotators and the supraspinatus muscle. Scapular muscle weakness may be associated to winging when performing wall push-ups, or active shoulder abduction and forward flexion. Special maneuvers include Neer’s and Hawkins’ tests to reproduce pain, apprehension testing to document anterior instability, posterior shoulder pain on apprehension test position for posterior impingement and O’Brien’s or anterior slide tests to look for labral pathology.

Functional assessment

Functional evaluation includes assessment of single leg balance, core stability and muscle strength in functional ranges of motion.¹ Analyzing the phases of the throwing cycle and evaluating the kinetic chain is essential. Analysis of upper extremity biomechanics is also helpful,⁶ as more than 50% of kinetic energy is transferred to the upper extremity via the legs and core in overhead throwers.⁷  

Imaging⁸

Plain radiographs: True shoulder anteroposterior (AP) view, axillary view, and supraspinatus outlet views.

Computer tomography (CT) arthrogram: Utilized in athletes when MRI is contraindicated for suspected rotator cuff tears, or labrum injuries.

Magnetic resonance imaging (MRI): Remains the gold standard to evaluate for rotator cuff disease.

• MRI arthrogram: recommended in cases with suspected labrum injuries. More specific (99%) and sensitive (95%) than MRI alone.
• The 3-Tesla (3T) MRI arthrogram is more sensitive than 3T-MRI without contrast for labrum evaluation. ⁹

Ultrasound:  Musculoskeletal ultrasonography is helpful for dynamic examination and to assess for rotator cuff injuries. It has comparable specificity and sensitivity to MRI in identification of rotator cuff injuries. However, the test is operator-dependent, and it is limited in its inability to provide a detailed intra-articular evaluation, except for the posterior labrum.^8,10

Early predictions of outcomes

Early identification of causative factors of injury, rapid response to relative rest, participation in flexibility and strengthening programs, and technique modification are all associated with better prognoses.

Social role and social support system

The throwing athlete may feel distress after an injury. Missing practice, games and possibly a whole season can cause social isolation, sleep disturbances, stress or mood disorders. Counseling and consideration of referral to a behavioral health specialist, ideally a sports psychologist, may be helpful to provide adequate coping mechanisms.

Rehabilitation Management and Treatments

Available or current treatment guidelines

A four-phase approach to rehabilitation has been suggested in the rehabilitation of the throwing shoulder.¹¹

• Phase 1: Reduction of pain and inflammation.
• Phase 2: Initiation of progressive strengthening.
• Phase 3: Advanced strengthening.
• Phase 4: Return to competitive throwing

At different disease stages

Analgesics, including non-steroidal anti-inflammatories (NSAIDs) may be considered. In athletes with severe pain, a short course of opiates may be appropriate, taking into consideration the risks and benefits of these drugs.¹² Alternatively, corticosteroid injections can be used as a diagnostic tool as well as minimize pain and promote participation in the rehabilitation process.¹³ Modalities such as ice, ultrasound, and electric stimulation may help to decrease symptoms. Other therapeutic measures to improve symptoms include soft tissue mobilization, stretching or kinesio tape.

There should be an initial emphasis in adequate posture and scapular stabilization, followed by pain-free range of motion of the glenohumeral and scapulothoracic articulations.¹¹ Isometric exercises of the rotator cuff and periscapular muscles is initiated, followed by pain-free progressive resistance exercises. Later in this phase, simulation of throwing mechanics without upper extremity use, general conditioning, proprioception, and flexibility exercises are recommended. Posteroinferior capsular stretching is recommended for throwers with GIRD greater than 5 degrees side-to-side difference in TRM.^1,13

Once full pain-free range of motion and normal strength is achieved, throwing mechanics can be addressed,managing the progressive volume and frequency of sporting drills.¹³

Coordination of care

Superior coordination among the physician, physical therapist, athletic trainer, coach and parents is required for successful rehabilitation and prompt return to play.

Patient & family education

• The physical therapist or athletic trainer should provide a home exercise program focused on periscapular and rotator cuff endurance exercises.
• Medications should be taken as prescribed, usually on daily basis for the first 1-2 weeks, followed by an as-needed basis.
• While symptomatic, the athlete should refrain from participating in activities that worsen symptoms, in some instances for periods up to 3 months.

Emerging/unique interventions

Return to play requires full pain-free range of motion and the ability to perform all tasks required by the sport, with excellent technique.

Failure of non-operative management is considered when there is no definite progress after several weeks. This is dependent on multiple factors including injury, time of season, level of athletic competition, and sport-specific requirements.

The decision for more aggressive treatment, which may include surgery, should ultimately be made by the athlete and his/her family after considering the information provided by the medical team and opinions from other health professionals.

Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

As most athletes have practice at the same time of day, creating a scheduled rehabilitation program during practice may promote better adherence.

Encourage all athletes to continue doing their full rehabilitation program for at least one month once they are fully asymptomatic. Keeping a calendar or diary of asymptomatic days may promote rehabilitation compliance.

Promote the use of some of the rehabilitation exercises, such as scapular strengthening and posteroinferior capsular stretches, as part of everyday warm-up and cool-down.

Enrolling assistance of a throwing coach or enrolling on a throwing program may be a good addition to the technical part of the sport.

Cutting Edge/Emerging and Unique Concepts and Practice

The Kerlan-Jobe Orthopaedic Clinic (KJOC) score is a subjective questionnaire that has been shown to be sensitive and specific in overhead athletes and had been validated in males, females¹⁹ and in multiples languages.  Scores range from 0-100. KJOC scores for asymptomatic overhead throwers should be greater than 90.¹⁴

Acute-to-chronic workload ratio (ACWR) is the ratio of the acute workload in one week to the average chronic workload over four weeks. A spike in ACWR may increase the risk of injury and has been suggested as vital to injury prevention and readiness in throwing sports.¹¹

To minimize risk factors such as high throwing volumes, an emphasis on pitching safeguards has increased, including the development of pitch count restriction recommendations based on age. It has been observed that pitch count monitoring does not account for a significant volume of pitching that occurs during warm-up and technique practice. These extra pitches should be closely monitored to help mitigate the risk of overuse injury.¹⁵

Gaps in the Evidence-Based Knowledge

The current evidence for electromyography use to determine muscle activity differences in patients with rotator cuff injuries is limited.¹⁶

On biomechanical analysis, the inclusion of more scapular markers to the ones currently used, wearable monitors and markerless tracking are future areas of studies.⁶

Platelet-rich-plasma for has been used for rotator cuff tendinopathy,¹⁷ glenohumeral laxity and GH labral injuries, yet good quality randomized studies to determine its effectiveness are still needed.¹⁷

Blood flow restriction is an emergent modality of athletic training and rehabilitation. Further studies are required to better understand such effects on the proximal site of occlusion in patients with shoulder pain.¹⁹

References

1. Mayes M, Salesky M, Lansdown DA. Throwing Injury Prevention Strategies with a Whole Kinetic Chain-Focused Approach. Curr Rev Musculoskelet Med. 2022 Apr;15(2):53-64
2. Zaremski JL, Zeppieri G, Tripp BL; Sport Specialization and Overuse Injuries in Adolescent Throwing Athletes: A Narrative Review. J Athl Train 2019; 54 (10):1030–1039.
3. Metha S, Tang S, et al. Chronic Workload, Subjective Arm Health, and Throwing Injury in High School Baseball Players: 3-Year Retrospective Pilot Study. Sports Health 2022 14:1, 119-126
4. Jobe FW, Kvnite RS. Shoulder pain in the overhand or throwing athlete: The relationship of anterior instability and rotator cuff impingement. Orthop Review. 1989;963-975.
5. Wilk KE, Macrina LC, Arrigo C. Passive range of motion characteristics in the overhead baseball pitcher and their implications for rehabilitation. Clin Orthop. 2012;470(6):1586-1594.
6. Trasolini NA, Nicholson KF, Mylott J, Bullock GS, Hulburt TC, Waterman BR. Biomechanical Analysis of the Throwing Athlete and Its Impact on Return to Sport. Arthrosc Sports Med Rehabil. 2022 Jan 28;4(1):e83-e91. 
7. Sciascia A, Thigpen C, Namdari S, Baldwin K. Kinetic chain abnormalities in the athletic shoulder. Sports Med Arthrosc Rev. 2012;20(1):16-21.
8. Zoga AC, Kamel SI, Hynes JP, Kavanagh EC, O’Connor PJ, Forster BB. The evolving roles of MRI and ultrasound in first-line imaging of rotator cuff injuries. American Journal of Roentgenology. 2021 Dec 23;217(6):1390-400.
9. Ajuied, A., McGarvey, C.P., Harb, Z. et al. Diagnosis of glenoid labral tears using 3-tesla MRI vs. 3-tesla MRA: a systematic review and meta-analysis. Arch Orthop Trauma Surg 138, 699–709 (2018).
10. Manske RC, Voight M, Page P, Wolfe C. The Application of Musculoskeletal Ultrasound in the Diagnosis of Supraspinatus Injuries. Int J Sports Phys Ther. 2023 Oct 1;18(5):88377. doi: 10.26603/001c.88377. PMID: 37799572; PMCID: PMC10549776.
11. Zaremski JL, Krabak BJ. Shoulder injuries in the skeletally immature baseball pitcher and recommendations for the prevention of injury. PM&R. 2012;4:509-517.
12. Martinez-Silvestrini, JA. Prescribing medications for pain and inflammation. In Frontera WR, Herring SA, Micheli, LJ, Silver JK, Young TP, eds. Clinical Sports Medicine. Philadelphia, PA; Saunders; 2006:193-205
13. Kibler WB, Sciascia A, Tokish JT, Kelly IV JD, Thomas S, Bradley JP, Reinold M, Ciccotti M. Disabled Throwing Shoulder: 2021 Update: Part 2—Pathomechanics and Treatment. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2022 May 1;38(5):1727-48..
14. Kraeutler MJ, Ciccotti MG, Dodson CC, Frederick RW, Cammarota B, Cohen SB. Kerlan-Jobe Orthopaedic Clinic overhead athlete scores in asymptomatic professional baseball pitchers. J Shoulder Elb Surg Am Shoulder Elb Surg Al. 2013;22(3): 329-332.
15. Zaremski JL, Zeppieri G Jr, Jones DL, Tripp BL, Bruner M, Vincent HK, Horodyski M. Unaccounted Workload Factor: Game-Day Pitch Counts in High School Baseball Pitchers-An Observational Study. Orthop J Sports Med. 2018; 6(6):1-7.
16. Spall P, Ribeiro DC, Sole G. Electromyographic Activity of Shoulder Girdle Muscles in Patients With Symptomatic and Asymptomatic Rotator Cuff Tears: A Systematic Review and Meta-Analysis. PM&R. 2016; 8(9):894–906
17. Eoghan T. Hurley, Charles P. Hannon, Leo Pauzenberger, Daren Lim Fat, Cathal J. Moran, Hannan Mullett, Nonoperative Treatment of Rotator Cuff Disease With Platelet-Rich Plasma: A Systematic Review of Randomized Controlled Trials. Arthroscopy: The Journal of Arthroscopic & Related Surgery, 2019; 35(5), 1584-1591.
18. Kara D, Ozcakar L, Demirci S, Huri G, Duzgun I. Blood Flow Restriction Training in Patients With Rotator Cuff Tendinopathy: A Randomized, Assessor-Blinded, Controlled Trial. Clin J Sport Med. 2024 Jan 1;34(1):10-16

Original Version of the Topic

William F. Micheo, MD, Julio A. Martinez-Silvestrini, MD. Shoulder Pain in the Throwing Athlete. 12/28/2012.

Previous Revision(s) of the Topic

Julio A. Martinez-Silvestrini, MD, William Micheo, MD, and Jason L Zaremski, MD. Shoulder Pain in the Throwing Athlete. 4/4/2017.

Julio A Martinez-Silvestrini, MD, William Micheo, MD, and Jason L Zaremski, MD. Shoulder Pain in the Throwing Athlete. 5/4/2021

Author Disclosures

Julio A Martinez-Silvestrini, MD
Nothing to Disclose

Jason Zaremski, MD
Nothing to Disclose

William Micheo, MD
Nothing to Disclose