Impingement of the shoulder
Impingement of the shoulder- Anatomy
A general discussion of the anatomy of the shoulder is necessary to understand what causes impingement of the shoulder. Your shoulder is made up of three distinct bones: your arm bone (the humerus), your shoulder blade (known as the scapula), and your collarbone (clavicle, Figure 1). Your humerus is kept in the shoulder socket (glenoid) by your rotator cuff. These muscles and tendons form a blanket around the head of the upper humerus and attach it to the scapula (Figure 2). There is fluid filled sac called a bursa between the rotator cuff and the bony structure on top of your shoulder (acromion). The bursa reduces the coefficient of friction and allows the rotator cuff tendons to move easily when moving the arm.
Impingement of the shoulder- Mechanism of injury
When lifting the arm to shoulder level, the space between the acromion and rotator cuff muscles decrease. The acromion can come into contact with the tendons and the bursa, causing inflammation and subsequent pain. Overhead athletes and weekend warriors alike can develop impingement over time with repetitive shoulder activity.
Impingement of the shoulder- Symptoms
Impingement can cause tenderness in the front of the shoulder and is generally associated with pain when you lifting your arm. Initially, the pain may be mild. Most individuals do not seek medical attention at this stage. Some of these symptoms include mild pain that is present with both overhead activity and rest. Pain may extend from the front of the shoulder to the side of the arm. Athletes who participate in overhead sport activities may have pain when throwing, serving a tennis ball or bowling. As the problem increases in severity, so too do the symptoms. Pain may be present at night and may be accompanied by loss of strength and motion. The individual may have trouble performing basic activities such as hygiene care and putting on clothes. It is important to note that impingement may not occur in isolation, as rotator cuff tears may be present at the same time.
Evaluation by your orthopedic surgeon
Whether by self-referral or by your primary care physician, your orthopaedic surgeon will perform a history and physical exam in addition to x-rays of the shoulder. If necessary, additional imaging such as a MRI may be obtained to evaluate the soft tissues, such as the rotator cuff in your shoulder.
Impingement of the shoulder- Treatment
The goals of treatment are pain reduction and restored function. When prioritizing treatment options, your orthopaedic surgeon considers several factors including age, pre-injury level of activity level, and overall health status. Initial management is typically nonsurgical. Although this form of treatment may take time, some patients experience improvement of symptoms and function. Examples of this initial treatment include rest, avoidance of overhead activities, and use of oral non-steroidal anti-inflammatory medications. If necessary, a formal outpatient physical therapy regimen may be initiated. If these initial treatments do not work, then your surgeon may opt to perform a steroid injection into the bursa beneath the acromion.
With failed nonsurgical treatment, the next step may be surgery. With impingement, the primary goal of surgery is to make more space for the rotator cuff. In order to accomplish this task, your surgeon will remove the inflamed bursa. Additionally, the orthopedist may also perform an acromioplasty, which involves partial removal of the undersurface of the acromion, known as a subacromial decompression. Current surgical techniques involve arthroscopic and open methods. With arthroscopy, small surgical implements are placed into two or three small incisions around the shoulder. The surgeon examines the shoulder through a fiberoptic scope connected to a camera. The surgeon performs all aspects of the surgery through the use of the specialized instruments with the video monitor. In a majority of cases, the anterior (front) end of the acromion is removed in conjunction with bursal tissue. The surgeon will address concomitant problems in the shoulder at the time of intervention, such as acromioclavicular arthritis, biceps tendon tears, and rotator cuff tears.