Internal impingement, also called posterior-superior glenoid impingement, describes painful contact between the greater tuberosity of the humerus (arm bone) and the posterosuperior glenoid (socket).
When the arm is cocked backward to throw, the humerus rotates until the labrum on the glenoid and the undersurface of the rotator cuff come into contact. Repetitive contact can result in tearing of the labrum and rotator cuff tissues.
What Is Internal Impingement?
Internal impingement commonly occurs during repetitive throwing or overhead activity.
Repeated throwing can also stretch the ligamentous stabilizers in the front of the shoulder. This can allow the humerus to shift forward and increase the severity of the internal impingement.
Internal impingement may occur without a tear or may be associated with tearing of the labrum and/or rotator cuff.
Causes and Risk Factors
Internal impingement may result from:
- Overuse of the shoulder from repetitive throwing or overhead activity
- Uncommonly, a fall on the arm while it is extended overhead
Risk factors include:
- Throwing and overhead sports such as baseball, tennis, and volleyball
- Swimming
- Poor physical conditioning, including strength and flexibility
- Loose ligaments or joints
Symptoms
Common signs and symptoms include:
- Pain around the shoulder, most frequently during the late cocking phase of throwing
- Pain during overhead hitting, such as in volleyball
- Decreased throwing velocity
- Decreased throwing accuracy
Treatment
Initial treatment may include:
- Medication and ice to relieve pain
- Stretching and strengthening exercises
- Modification of the activity that caused the symptoms
- Physical therapy or treatment with an athletic trainer when recommended
Treatment focuses on strengthening the rotator cuff and shoulder blade muscles to help stabilize the shoulder and optimizing shoulder range of motion to minimize impingement in the back of the shoulder.
Correcting throwing mechanics and gradually returning to throwing with an interval throwing program are also important.
A cortisone injection around the tendon within the bursa is rarely recommended.
If conservative treatment does not improve symptoms, arthroscopic surgery may be indicated to repair or debride torn labrum or rotator cuff tissue and, in some cases, tighten the stretched capsule and ligaments in the front and lower portion of the shoulder.
Recovery and Outcomes
Painful internal impingement without labral or rotator cuff tears may improve with conservative treatment, including avoiding aggravating activities, rehabilitation exercises, correction of throwing mechanics, and gradual return to overhead activity.
Internal impingement associated with labral and/or rotator cuff tears often requires arthroscopic surgery to repair the tears and address loose ligaments in the front of the shoulder.
Following surgery, return to activity is usually possible within four to six months. Additional time may be required to return to specific sports activities such as pitching.
Potential complications include:
- Labral tear
- Rotator cuff tendon tear
- Recurrence of symptoms, especially if poor mechanics are not corrected
- Shoulder stiffness or loss of motion following surgery
- Difficulty returning to overhead throwing and/or hitting
When to See Dr. Chudik
If shoulder pain develops with throwing or overhead activity, particularly with decreased throwing velocity or accuracy, or if symptoms persist or worsen, schedule an evaluation with Dr. Chudik.
Call 630-324-0402, request an appointment online, or email contactus@chudikmd.com.