Internal impingement, or 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 backwards to throw, the humerus rotates until there is contact between the labrum on the glenoid and the undersurface of the rotator cuff muscles on the humeral head. This repetitive contact can result in tearing of the labral and rotator cuff tissues.
What Is Internal Impingement?
Repetitive throwing can cause the anterior (front) ligamentous stabilizers of the shoulder to stretch out and allow the humerus to shift forward, increasing the severity of the internal impingement.
As the shoulder repeatedly moves through the throwing motion, contact between the labrum and undersurface of the rotator cuff can result in injury to these tissues and cause pain.
Causes and Risk Factors
Causes and risk factors for internal impingement can include:
- Overuse of the shoulder due to repetitive throwing or overhead activity
- Uncommonly, a fall on the arm extended overhead
- Throwing or overhead sports, such as baseball, tennis, or volleyball
- Swimming
- Poor physical conditioning, including strength and flexibility
- Loose ligaments or joints (“double jointed”)
Symptoms
Frequent signs and symptoms of internal impingement include:
- Pain around the shoulder, most frequently during the late cocking phase of throwing or overhead hitting in volleyball
- Decreased velocity and accuracy when throwing
Diagnosis
Internal impingement involves painful contact between the greater tuberosity of the humerus and the posterosuperior glenoid. Repetitive contact can result in tearing of the labral and rotator cuff tissues.
Treatment
Initial treatment consists of medication and ice to relieve pain, stretching and strengthening exercises, and modification of the activity that initially caused the problem. Referral to a physical therapist or athletic trainer may be recommended.
Treatment is geared toward the rotator cuff and shoulder blade muscles to help stabilize the shoulder, as well as optimizing shoulder range of motion to minimize impingement in the back of the shoulder. It is important to correct throwing mechanics and gradually return using an interval throwing program.
An injection of cortisone to the area around the tendon is rarely recommended.
If conservative treatment fails to improve symptoms, arthroscopic surgery may be indicated to repair or debride the torn labrum and rotator cuff tissues and, sometimes, to tighten a stretched anteroinferior capsule and ligaments.
Recovery and Outcomes
Painful internal impingement without tears of the labrum or rotator cuff may improve with conservative treatment consisting of avoidance of aggravating activities, rehabilitation exercises, correction of throwing mechanics, and gradual return to overhead activities.
Internal impingement with labral and/or rotator cuff tears often requires arthroscopic surgery to repair tears and address loose ligaments in the front of the shoulder to alleviate symptoms.
Return to activity is usually possible four to six months after surgery, with additional time required for return to specific sports activity such as pitching.
When to See Dr. Chudik
If shoulder pain persists or worsens, particularly during throwing or overhead activities, or symptoms continue despite activity modification and conservative treatment, contact Dr. Chudik’s office for an evaluation.
Call 630-324-0402, email contactus@chudikmd.com, or request an appointment online.