Recovery and Rehabilitation from Subacromial Impingement Syndrome
A comprehensive rehabilitation plan can help a patient manage subacromial impingement syndrome and prevent further injury.
One of the more common cases seen with regard to upper-extremity injury is subacromial impingement syndrome (SIS) or (SAIS). This generally refers to a condition where tendons of muscles in the shoulder (rotator cuff) get caught or pinched between the humerus and the acromion. The cause of this particular condition can range from bony deformity that causes an accelerated wearing of the cuff tendons—structural impingement—to postural deficiencies and muscle weaknesses that constitute functional impingement. These causes can alter the alignment and biomechanical efficiency of the shoulder complex. In most cases, a thorough history and evaluation can identify this issue relatively easily. However, the more complicated issue becomes how to address the primary cause of the injury, as well as to identify and correct any underlying causes.
Addressing the most apparent cause of the impingement begins with looking at the glenohumeral joint itself. Relieving any capsular restrictions that may be contributing to the impingement is widely accepted as the first step in minimizing pain. Long axis distraction as well as inferior and posterior glides are indicated to stretch the overtightened capsule. This reduces the upward glide of the humeral head into the acromion and promotes proper arthrokinematics of the glenohumeral joint. Generally, patients with SIS will have painful arc in abduction of 60 to 120 degrees. Educating the patient to avoid this range with repeated or prolonged active movement can continue to reduce irritation of tissues. However, passive movement within this range of motion can help take advantage of the mobility created by the passive joint mobilization.
Likewise, it can begin neuromuscular re-education and increase kinesthetic awareness within the joint. The passive range is acceptable to perform so long as it remains pain-free and can be done both in the clinic and at home using an over-the-door pulley system such as the Thera-Band Shoulder Pulley system from Thera-Band, Akron, Ohio. As pain continues to diminish and range of motion increases, the patient can move to active assisted range using the pulley system to begin mild strengthening of the musculature around the shoulder.
Rebuilding Muscle Strength
Once capsular restrictions have been reduced and pain is under control, strengthening the muscles around the shoulder complex becomes a priority. The newly established passive range must be supported by adequate muscle strength to maintain biomechanical efficiency. Generally, with SIS, the pattern observed is weakness and overlengthening in muscles on the posterior aspect of the body, including lower trapezius, rhomboids, infraspinatus, teres minor, and posterior deltoid. In addition, tightness and weakness in other musculature can be seen. These muscles include pectoralis major and minor, upper trapezius, and levator scapulae. This combination can lead to the tendency of the scapula to elevate and protract. The humerus can internally rotate as well, with the head of the humerus sitting anterior and superior in the glenoid. All of these positions can cause and/or exacerbate the symptoms of SIS.
Exercises for Strengthening
Exercises to strengthen these muscles initially can include resisted scapular retraction, external humeral rotation, internal humeral rotation, and shoulder extension. These particular strengthening exercises occur with the shoulder joint in minimal abduction and should allow for increase in strength without increase in pain. These exercises can be done in the clinic on a BodyCraft PFT functional trainer by BodyCraft, a division of Recreation Supply Inc, based in Lewis Center, Ohio. This device allows adjustment of resistance and angle of pull for the exercises.
An aspect of this product that can make it particularly useful is that the patient can replicate these exercises in a home exercise program with the use of Thera-Band or Thera-Band exercise tubing, from The Hygienic Corporation, Akron, Ohio, or Warminster, Pa-based Stretchwell Inc, manufacturer of Fit-Lastic therapy products. As strength of the shoulder complex increases, some of the focus can move to scapular mobilization and stabilization exercises.
For the glenohumeral joint to function, there must be a good balance of scapular mobility and stability. Since the scapula makes up half of the glenohumeral joint, good scapulothoracic rhythm allows for proper alignment of the glenohumeral joint so that forces can be passed in a manner that is nondestructive to the tissues in and around the joint. The resisted retraction exercise mentioned previously is one of the exercises that addresses this.
Resisted scapular protraction is another exercise to consider. This can be done using a therapy band or functional trainer. This exercise can even be performed without additional equipment by placing the patient in a quadruped position and having them perform a “sternum drop,” strengthening serratus ante resistance. Care must be taken to emphasize the activation of serratus anterior over pectoralis major and minor to avoid recreation of excessive protraction and internal humeral rotation as seen already in a patient with SIS.
As the patient becomes stronger, they can progress to a therapy band of heavier resistance or move from quadruped to a full plank position for the sternum drop. Another way to progress this exercise is to have the patient use a dumbbell, kettlebell, or another unstable resistance to protract in a supine position. Combining scapular protraction, retraction, elevation, and depression into one movement creates circumduction of the scapula. The ability of the scapula to move in a combination of planes provides the best foundation for functional movement of the upper extremity and allows for good coordination of the musculature surrounding the scapula.
Pulley systems also provide resistance for exercises that target a range of upper-extremity muscles. Endorphin Corp, based in Pinellas Park, Fla, offers a complete line of free-standing and wall-mountable pulley systems for this type of activity. If the patient or clinic has access to Pilates equipment, the Trapeze Table by the Sacramento, Calif-based Balanced Body can be used to do both assisted and resisted circumduction of the scapula.
Scapular stability is the other side of proper shoulder function because once mobility is re-established, the ability to control that mobility must be developed. Closed-chain upper-extremity exercises are a great way to challenge scapular stability while building upper-extremity strength. Bench presses using dumbbells or kettlebells are another way to build upper-extremity strength and scapular stability by making the resistance less linear. For home exercises, sternum drops in full plank position transition well into modified or full push-ups for closed-chain movements. Double- and single-arm Thera-Band chest presses are more dynamic movements that can also be performed at home.
Rehabilitation for Restoring Function
Good overall shoulder function ultimately depends on how well the humerus connects, through the scapula, into the rest of the body. This idea of integration is what makes the body most efficient at spreading the work of any movement across multiple joints and reducing the risk of injury from forces accumulating at any one joint. So far, the discussion of SIS rehabilitation has been by section of the body, first looking at the glenohumeral joint, then the scapulothoracic connection. What must also be given attention are thoracic mobility, lumbopelvic stability (commonly referred to as core stability), and gluteus strength. This integration from the ground up with reference to shoulder function is important for everyday use, and critical for any jobs or activities that require arms to be overhead. It is also vital in any throwing sport or sport that includes overhead motion, such as tennis or swimming.
Thoracic extension is one of the movements in the spine that is important for any overhead motion. A lack of this is one of the postural deficits generally seen among patients with SIS. With an excessive thoracic kyphosis and resulting lack of extension, two things happen. The first is that the scapula is forced into protraction, causing overlengthening and weakness of the scapular stabilizers, as well as tightness of the other musculature mentioned earlier. The second thing is that without adequate thoracic extension, the scapula cannot properly downglide to allow the humerus to go into overhead flexion. This results in the greater tubercle of the humerus approximating the acromion on the scapula and pinching the tendons of the rotator cuff during overhead movements of the humerus.
Thoracic extension can be worked on passively by having the patient lay supine over a foam roller and conduct deep breathing exercises and/or various upper-extremity ROM exercises if the patient has established control of scapular patterning. If a full foam roller is too aggressive, then a half roller can be used. Axis foam rollers from OPTP, Minneapolis, are an option, in addition to Magic Rollers by Balanced Body, which offer a good combination of firmness and softness.
Thoracic rotation is also important to work on if there is any limitation, especially among throwing athletes. A limitation in thoracic rotation can cause an overloading of the rotator cuff in eccentric contraction during follow-through after a throw. This occurs because the rotator cuff is used primarily to decelerate the humerus after a throw if the thoracic spine is unable to rotate.
Any resulting trauma to the rotator cuff can cause weakness and tightness, leading to the biomechanical deficiencies related to SIS. Both thoracic extension and rotational mobility can be isolated using the Combo Chair from Balanced Body. The High/Low Combo Chair is designed to easily convert from one mode to another, and this type of equipment is used for Pilates chair exercises.
Finally, core stability and gluteus strength can be addressed as the foundation upon which shoulder function is based. Again, this will be helpful for daily function among most people. However, it is very important in the idea of integration for athletes to efficiently use ground reaction forces to maximize force output at the moving extremity. Essentially, if there is any weak link in the kinetic chain, there is the potential for loss of power and injury.
Core strength serves to link the upper body to the lower body for efficient transfer of energy. Gluteus strength again allows for a connection into the lower extremity and ground. Also, good strength of the gluteals acts as a braking force to decelerate the torso via fascial and muscular connections to the opposite scapula with rotational acceleration. This action of deceleration can help to reduce forces placed on the rotator cuff for throwing and overhead activities.
SIS Recovery and Management
SIS is a common diagnosis, and one that can present among individuals of varying fitness and activity levels. If identified early and approached with a global view, it can be managed relatively well. Along with biomechanical counseling and a comprehensive home exercise plan, it is possible for the patient to return to a preinjury level of activity as well as avoid further injury. PTP
Dane Burke, PT, ATC, is owner of Northstar Pilates Solutions LLC and has been practicing physical therapy and teaching Pilates for more than 10 years in Buffalo, NY. He is certified through the Pilates Method Alliance and Polestar Education. For more information, contact PTPEditor@nullallied360.com.
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