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, numbness, loss of throwing velocity or control, and snapping or catching about the shoulder.
- Shoulder pain in the overhead throwing athlete may be related to repetitive trauma (overuse), biomechanical abnormalities and/or poor technique.
- Pain may be attributed to primary subacromial impingement or to shoulder instability with associated secondary subacromial impingement.
- In skeletally immature athletes, repetitive throwing can cause compromise of the proximal humeral physis
- Shoulder instability may be secondary to congenital ligamentous instability, acquired microinstability or following traumatic dislocation.
Epidemiology including risk factors and primary prevention
- Poor throwing mechanics
- Previous shoulder injury
- Previous spine or contralateral leg injuries
- Glenohumeral (GH) laxity
- Primary laxity or secondary to previous trauma
- Weak rotator cuff musculature
- Poor endurance or weak periscapular musculature
- High volume of activity (pitches per game, months per year)
- Throwing velocity
- Periscapular muscle strengthening
- Rotator cuff endurance and strengthening exercises
- Adequate dominant shoulder range of motion, compared to the contralateral side 1, 2.
- Core stability
- 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)
The shoulder has been compared to a “ball on a seal’s nose” with high degree of mobility and limited stability.3 With humeral motion, the periscapular musculature positions the scapula. The rotator cuff and deltoid elevates 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 glenoid labrum tears.
Peak forces may surpass 500 N-m and angular speeds of 7000 arc degrees/second.4 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 above reasons are why prevention of shoulder injuries are difficult to prevent in overhead throwing athletes. The “Thrower’s Paradox” model 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 training5.
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
- 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.
- 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.
- 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, micro-instability and ultimately rotator cuff and labral tears.
Specific secondary or associated conditions and complications
- Subacromial bursitis
- Rotator cuff tendinopathy
- Rotator cuff tear
- Superior labrum anterior-posterior (SLAP) injury
- Posterior GH impingement
- Glenohumeral Internal Rotation Deficit
- Total Range of Motion Deficit of the GH joint
- Suprascapular neuropathy
- Quadrilateral space syndrome (involving the axillary nerve)
- Anterior capsular insufficiency
- Posterior capsular tightness
- Bicipital tendinopathy
- Medial epicondylopathy/ulnar collateral ligament (UCL) injury
- Periscapular muscle dysfunction/myofascial pain
- Proximal humeral epiphysiolysis
2. ESSENTIALS OF ASSESSMENT
The overhead throwing athlete reports gradual onset of pain during activity, which progresses to pain at rest and even at night. There may be a history of high volume of activity, increasing velocity of pitches or previous injury that was not rehabilitated. Pain may be associated to specific phases of throwing (cocking, acceleration and/or deceleration), “dead arm” sensation or change in performance. There are also other important questions specific to overhead throwing athletes that may clue a provider into what the injury may be. See table 1 below.
Table 1: Important Historical Questions in Overhead Throwing athletes With Shoulder Pain
|How many times has your throwing shoulder hurt in the past?|
|Does pain begin at the beginning, in the middle, or end of games/practice?|
|How many innings (and if available pitches) do you pitch a week?|
|How many teams do you play on at the same time?|
|What positions due to play?|
|If you pitch, do you also catch?|
|When was the last time you had time off from throwing?|
|How many weeks or months did you have off per 12 months?|
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 reduced glenohumeral internal rotation (GIRD).3 If there is a difference of more than 17 degrees of internal rotation (IR) compared to ER, GIRD may be a cause of shoulder pain. The total arc of motion (TRM) may be another physical examination measurement to predict throwing injury. TRM is measured by adding ER and IR at 90° of abduction together. TRM in the throwing shoulders should be within 5 degrees of the non-throwing shoulder. If not, this may be a contributing factor to shoulder injuries in overhead throwers6. Manual muscle testing reveals weakness of the external rotators and the supraspinatus muscle when testing abduction in the scapular plane. 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 instability, posterior shoulder pain on apprehension test position for posterior impingement and O’Brien’s or scapular slide tests to look for labral pathology.
Functional evaluation includes assessment of single leg balance, muscle strength in functional ranges of motion7, and integration of the whole kinetic chain in sports-specific motions. Kinetic chain assessment is instrumental in overhead throwing athletes as data has revealed that more than 50% of kinetic energy is transferred to the upper extremity via the legs and core in overhead throwers8. Additionally, evaluation of pitching technique, throwing biomechanics should also be performed.
Plain radiographs: True shoulder anteroposterior view, axillary view, and supraspinatus outlet views.
Computer tomography (CT): Utilized in athletes when MRI is contraindicated.
- CT arthrogram: may provide more information in patients with 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.11
Ultrasound: Musculoskeletal Ultrasonography is valuable in assessing rotator cuff complete and partial tears. It is also 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.9, 11
Supplemental assessment tools
Dynamic examination under ultrasound guidance may help determine subcoracoid or other types of dynamic impingement.
Video and computer-generated motion analysis and use of dynamic electromyogram (EMG) studies performed by biomechanics laboratories may be beneficial in instances in which patients are not improving and abnormal biomechanics and poor technique are present.
Early predictions of outcomes
Early identification of causative factors of injury, rapid response to relative rest, participation in flexibility and strengthening programs, as well as 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 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.
3. 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. 7, 12
- Phase 1: Reduction of pain and inflammation.
- Phase 2: Initiation of progressive strengthening.
- Phase 3: Advanced strengthening.
- Phase 4: Return to competitive throwing
Please refer below for a more detailed description of this rehabilitation model.
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.13 Alternatively, corticosteroid injections are useful to minimize pain and promote participation in the rehabilitation process,14 Modalities such as ice, ultrasound, electric stimulation and other therapeutic measures, such as soft tissue mobilization, posterior capsular stretching or kinesiotape may also help to decrease symptoms.
There should be initial emphasis in adequate posture and scapular stabilization, followed by pain-free range of motion of the glenohumeral and scapulothoracic articulations.12 Isometric exercises of the periscapular muscles, as well as rotator cuff musculature is initiated, followed by pain-free progressive resistive exercises. Later in this phase, simulation of throwing mechanics without upper extremity use, as well as general conditioning (proprioception, flexibility and aerobic) exercise are recommended. Posteroinferior capsular stretching is recommended for throwers with GIRD greater than 25 degrees.10
Once full pain-free range of motion is achieved, throwing mechanics can be addressed, gradually increasing number of repetitions, distance and throwing speed (one variable per time) with a supervised throwing program, until the athlete can throw pain-free at full speed from the mound.7
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 (prn) basis.
- While symptomatic, the athlete should refrain from participating in activities that worsen symptoms, in some instances for periods up to 3 months.
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; sport, 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 taking into account 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 exercise program during practice may promote better adherence to the rehabilitation regimen.
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 posteroinferor capsular stretches, as part of everyday warm-up and cool-down.
Enrolling assistance of a throwing coach or enrolling on a throwing program, while not adding significant volume to the number of throws may be a good addition to the technical part of the sport.
Continued use of therapeutic modalities such as ice and electrical stimulation may aid in recovery.
4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE
One new measure that could identify injury is the Kerlan-Jobe Orthopedic Clinic Shoulder and elbow (KJOC) score. The KJOC score is a subjective questionnaire that has been shown to be sensitive and specific in overhead athletes. Scores range from 0-100. KJOC scores for asymptomatic overhead throwers should be greater than 90.15,16
5. 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.17
Protein-rich-plasma for has been used for rotator cuff tendinopathy18 and GH labrum injuries, yet good quality randomized studies to determine its effectiveness are still needed
- Cole S, Sanderson T, McNeill B, et al. A Proposal for Functional Screening of the Throwing Kinetic Chain in Baseball Pitchers to Assess Shoulder and Elbow Injury Risk. Sport Exerc Med Open J. 2015; 1(5): 151-158.
- Shanley E, Kissenberth MJ, Thigpen CA, et al. Preseason shoulder range of motion screening as a predictor of injury among youth and adolescent baseball pitchers. J Shoulder and Elbow Surg. 2015; 24 (7): 1005–1013
- 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.
- Dillman CJ, Fleisig GS, Andrews JR. Biomechanics of pitching with emphasis upon shoulder kinematics. J Orthop Sports Phys Ther. 1993;18:402-408.
- Wilk KE, Obma P, Simpson CD, Cain EL, Dugas JR, Andrews JR. Shoulder injuries in the overhead athlete. J Orthop Sports Phys Ther. 2009;39(2):38-54.
- 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.
- Wilk KE, Arrigo C. Current concepts in the rehabilitation of the athletic shoulder. J Orthop Sports Phys Ther. 1993;18:365-378.
- Sciascia A, Thigpen C, Namdari S, Baldwin K. Kinetic chain abnormalities in the athletic shoulder. Sports Med Arthrosc Rev. 2012;20(1):16-21.
- Lenza M, Buchbinder R, Takwoingi Y, Johnston RV, Hanchard NC, Faloppa F. Magnetic resonance imaging, magnetic resonance arthrography and ultrasonography for assessing rotator cuff tears in people with shoulder pain for whom surgery is being considered. Cochrane Database Syst Rev. 2013;(9):CD009020.
- Burkhart SS, Morgan CD, Kibler WB. The disabled throwing shoulder: spectrum of pathology. Part I: pathonantomy and biomechanics. 2003;404-420.
- De Jesus JO, Parker L, Frangos AJ, Nazarian LN. Accuracy of MRI, MR arthrography, and ultrasound in the diagnosis of rotator cuff tears: A meta-analysis. Am J. Roentgenology. 2009;92(6):1701-1707.
- 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.
- 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.
- Cavallo J, Speer KP. Shoulder instability and impingement in throwing athletes. Med Sci Sports Med. 1998;30(4):S18-25.
- Franz JO, McCulloch PC, Kneip CJ, Noble PC, Lintner DM. The utility of the KJOC score in professional baseball in the United States. Am J Sports Med. 2013;41(9):2167-2173.
- 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.
- 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
- Kesikburun S, Tan AK, Yilmaz B, Yaşar E, Yazicioğlu K. Platelet-rich plasma injections in the treatment of chronic rotator cuff tendinopathy: a randomized controlled trial with 1-year follow-up. Am J Sports Med. 2013 Nov;41(11):2609-16
Original Version of the Topic
William F. Micheo, MD and Julio A. Martinez-Silvestrini, MD. Shoulder pain in the throwing athlete. 12/28/2012.
Julio Martinez-Silvestrini, MD
Nothing to Disclose
William Micheo, MD
Nothing to Disclose
Jason L Zaremski, MD
Nothing to Disclose