Internal impingement is a condition that causes shoulder pain from within the joint. Unlike the more well-known subacromial impingement, which involves structures on the outside of the rotator cuff, internal impingement occurs when the rotator cuff rubs or gets pinched against the deeper parts of the shoulder, such as the labrum or the glenoid. This rubbing can cause pain, fraying, or even tears in the rotator cuff and labrum.
How Common It Is and Who Gets It? (Epidemiology)
Internal impingement is a significant source of shoulder pain, particularly in overhead athletes like baseball pitchers, swimmers, and tennis players. While it can also affect non-athletes, the condition is most common in young to middle-aged individuals who engage in repetitive overhead movements.
Why It Happens – Causes (Etiology and Pathophysiology)
The condition is caused by abnormal contact between the undersurface of the rotator cuff and the glenoid labrum, often during overhead activities or throwing motions. This can lead to fraying of the rotator cuff or irritation of the labrum. The impingement occurs most frequently when the arm is in maximum abduction and external rotation during late cocking or early acceleration phases of throwing.
How the Body Part Normally Works? (Relevant Anatomy)
The glenohumeral joint consists of the humeral head and the glenoid, which are surrounded by the rotator cuff muscles, ligaments, and the labrum. The rotator cuff helps stabilize the humeral head within the glenoid. When the rotator cuff is damaged or pinched, it can cause pain, reduce the range of motion, and interfere with normal shoulder mechanics.
What You Might Feel – Symptoms (Clinical Presentation)
Patients with internal impingement often report shoulder pain, especially during overhead movements or lifting the arm forward. They may also experience pain while sleeping on the affected side, as well as popping, clicking, or catching sensations. Stiffness and decreased range of motion are common, and athletes, especially throwers, may notice a decline in performance.
How Doctors Find the Problem? (Diagnosis and Imaging)
Internal impingement is challenging to diagnose because its symptoms overlap with other shoulder conditions. MRI may not always reveal the problem. Arthroscopy is often the most effective diagnostic tool, allowing the surgeon to directly observe the impingement, particularly during maneuvers like the Hawkins test.
Classification
There is no formal classification scheme for internal impingement. However, it can involve fraying of the rotator cuff, labral lesions, or hypertrophy of the posterior capsule.
Other Problems That Can Feel Similar (Differential Diagnosis)
Internal impingement can be confused with subacromial impingement, rotator cuff tears, or labral tears. A thorough clinical exam, physical testing, and imaging are necessary to differentiate between these conditions.
Treatment Options
Non-Surgical Care
- Physical therapy to improve strength and flexibility
- Rest and modification of activities
- Anti-inflammatory medications or corticosteroid injections
Surgical Care
- Arthroscopic debridement to remove damaged tissue
- Labral repair if the labrum is detached
- Occasionally, posterior capsule release if tightness is contributing to the impingement
Recovery and What to Expect After Treatment
Recovery from arthroscopic surgery typically involves wearing a sling for the first few weeks, followed by physical therapy. Most patients return to normal activity within a month or two, although athletes may require more rehabilitation.
Possible Risks or Side Effects (Complications)
Complications are rare but can include infection, nerve injury (e.g., axillary nerve), and delayed recovery or recurrence of symptoms. The risk of full-thickness rotator cuff tears is also present, especially in throwing athletes.
Long-Term Outlook (Prognosis)
With appropriate treatment, most patients recover fully. Athletes often return to their sport after completing rehabilitation. However, a small percentage may experience persistent symptoms or a slower recovery if the rotator cuff is significantly damaged.
Out-of-Pocket Costs
Medicare
CPT Code 29823 – Shoulder Debridement (Arthroscopic Debridement for Joint Damage): $141.22
CPT Code 29807 – Labral Repair (Arthroscopic Repair of the Glenoid Labrum): $244.79
Medicare Part B typically covers 80% of the approved cost for these procedures once your annual deductible has been met, leaving you responsible for the remaining 20%. Supplemental Insurance plans such as Medigap, AARP, or Blue Cross Blue Shield generally cover the remaining 20%, minimizing or eliminating out-of-pocket expenses for Medicare-approved surgeries. These supplemental plans coordinate with Medicare to fill the coverage gap and reduce financial responsibility.
If you have Secondary Insurance, such as TRICARE, an Employer-Based Plan, or Veterans Health Administration coverage, it acts as a secondary payer. These plans typically cover any remaining balance, including coinsurance or small deductibles, which generally range from $100 to $300, depending on your plan and provider network.
Workers’ Compensation
If your shoulder debridement (CPT 29823) or labral repair (CPT 29807) is required due to a work-related injury, Workers’ Compensation will cover all associated medical expenses, including surgery, rehabilitation, and follow-up care. You will not have any out-of-pocket expenses, as the employer’s insurance carrier directly covers all approved treatments.
No-Fault Insurance
If your shoulder condition is related to an automobile accident, No-Fault Insurance will typically cover the total cost of your treatment, including surgery and postoperative care. The only potential out-of-pocket cost may be a small deductible or co-payment depending on your insurance policy.
Example
Sarah Williams underwent labral repair surgery (CPT 29807) after a shoulder injury. Her estimated Medicare out-of-pocket cost was $244.79 for the repair, and $141.22 for her shoulder debridement (CPT 29823). Since Sarah had supplemental insurance through Blue Cross Blue Shield, her remaining balance was fully covered, leaving her with no out-of-pocket expenses for both procedures.
Frequently Asked Questions (FAQ)
Q. What is internal impingement of the shoulder?
A. Internal impingement is a condition where the rotator cuff tendons get pinched between the humeral head and the glenoid when the arm is in an abducted and externally rotated position.
Q. What causes internal impingement?
A. It is commonly seen in overhead athletes and results from repetitive throwing or overhead activities that lead to pinching of the rotator cuff tendons.
Q. What are the symptoms of internal impingement?
A. Symptoms include shoulder pain during overhead activities, decreased performance, and sometimes clicking or a catching sensation.
Q. How is internal impingement diagnosed?
A. Diagnosis is based on a detailed history, physical examination, and imaging studies such as MRI to evaluate the rotator cuff and labrum.
Q. What non-surgical treatments are available for internal impingement?
A. Non-surgical options include rest, activity modification, physical therapy, anti-inflammatory medications, and sometimes injections.
Q. When is surgery considered for internal impingement?
A. Surgery is considered if non-surgical treatments fail to relieve symptoms and the patient has ongoing pain and loss of function.
Q. What does arthroscopic treatment of internal impingement involve?
A. The procedure involves debridement or repair of the rotator cuff and labrum, removal of inflamed tissue, and addressing any contributing pathology.
Q. What is the recovery time after arthroscopic treatment?
A. Recovery time varies but generally involves a period of rest, followed by physical therapy to regain motion and strength.
Q. Will I need physical therapy after surgery?
A. Yes, physical therapy is essential after surgery to help restore shoulder motion, strength, and function.
Q. Can athletes return to sports after arthroscopic treatment for internal impingement?
A. Many athletes are able to return to their sport after completing rehabilitation and regaining full shoulder function.
Summary and Takeaway
Internal impingement is an often overlooked cause of shoulder pain, particularly in overhead athletes and individuals engaged in repetitive overhead motions. Symptoms include pain during overhead activities, clicking or popping, and a reduced range of motion. Diagnosis can be challenging, but arthroscopy is the most accurate method for direct visualization. Most cases are initially treated with physical therapy and lifestyle modifications, and surgery is reserved for those who fail conservative treatments. Recovery is generally favorable with most patients returning to normal function after surgery, but a few may experience delayed recovery. Prevention focuses on maintaining shoulder mechanics and avoiding repetitive strain. If conservative treatments do not provide relief, consulting a specialist is recommended.
Clinical Insight & Recent Findings
A recent study conducted an international survey to assess the diagnosis and treatment of internal impingement syndrome (IIS) among orthopedic surgeons. It found that most surgeons are familiar with IIS, but its management varies between regions. The study revealed that surgeons outside of France, particularly those in Japan, reported more cases of IIS, likely due to the prevalence of baseball, a sport known to commonly cause this condition. Despite its rarity, the condition presents with distinct symptoms such as posterior shoulder pain during arm cocking. Non-operative treatments such as physical therapy and corticosteroid injections were commonly used, though surgical options like debridement and labral repair were considered when conservative treatments failed. The study concluded that while awareness of IIS is widespread, further research is needed to standardize treatment protocols and improve outcomes, especially in overhead athletes. (“Study on internal impingement syndrome – see PubMed.”)
Who Performs This Treatment? (Specialists and Team Involved)
Shoulder specialists, including orthopedic surgeons and sports medicine physicians, are the primary providers of care for internal impingement. Physical therapists specializing in shoulder rehabilitation are also critical to recovery.
When to See a Specialist?
Consider seeing a shoulder specialist if you have persistent shoulder pain that does not improve with rest or physical therapy, especially if you have difficulty performing overhead activities or experience clicking, popping, or catching sensations.
When to Go to the Emergency Room?
If you experience severe shoulder pain after a traumatic injury or if you have signs of infection, such as fever or redness at the surgical site, seek emergency medical attention.
What Recovery Really Looks Like?
Post-surgery recovery typically involves using a sling for the first few weeks, followed by physical therapy to regain motion and strength. Most patients can return to normal activities within a few months, although athletes may need longer rehabilitation.
What Happens If You Ignore It?
If left untreated, internal impingement can lead to worsening pain, reduced mobility, and, in some cases, progressive rotator cuff tears or labral damage. This may lead to chronic pain or disability.
How to Prevent It?
Prevention involves maintaining proper shoulder mechanics, particularly during overhead activities. Regular stretching, strengthening exercises, and avoiding repetitive strain can help prevent internal impingement.
Nutrition and Bone or Joint Health
A diet rich in vitamins and minerals, such as calcium and vitamin D, supports joint and bone health. Anti-inflammatory foods may also help reduce pain and promote healing in individuals with shoulder injuries.
Activity and Lifestyle Modifications
Avoid repetitive overhead motions if you experience shoulder pain. Strengthening and stretching exercises for the rotator cuff and scapular stabilizers are key components of preventing internal impingement and improving shoulder function.
