Rotator Cuff Rehab
Brooks Cherry
Rehab Techniques 4-16-2002
Introduction
Over the last few years, we have learned more about shoulder mechanics
and the understanding of the pathophysiology of injury. The shoulder is
the most mobile joint in the human body, the result of complex anatomical and
biomechanical relationships (Baker, 2000). As a result, the shoulder
is much more prone to injuries than the hip which is a ball and joint socket.
The shoulder is involved in 8 to 13% of all sports related injuries, with
reports indicating complaints of shoulder pain among up to 50% of competitive
swimmers (Anderson, 1995). It is also been reported that professional
baseball players especially pitchers complain of shoulder pain at some point
in their career. Most injuries to the rotator cuff in sports are usually
a result of microtrauma from repetitive overhead movements. The repetitive
microtraumatic stresses placed on the athletes shoulder joint complex during
the throwing motion challenge the physiological limits of the surrounding tissues(Wilk,
2002). Athletic injuries to the shoulder most commonly involve the glenohumeral
joint and the rotator cuff musculature. A complete understanding of the
functional anatomy of the shoulder will give the cliniciana foundation for taking
care of shoulder injuries. My purpose is to review the anatomy, biomechanics,
mechanisms of injury and the rehabilitation plan of rotator cuff injuries in
athletes.
Anatomy
We examine the shoulder
girdle from the standpoint of its component structures, namely the (1) bony
anatomy (humerus, clavicle, scapula), (2) bony and muscular articulations (glenohumeral,
acromioclavicular, sternoclavicular, and scapulothoracic), (3) static stabilizers
(labrum, capsule, ligaments), (4) muscles or dynamic stabilizers (rotator cuff,
deltoid, and scapular stabilizers)(Terry, 2000). These four separate
components work together to produce shoulder movement as a dynamic unit. If
one or more of these structures through overuse or acute trauma disrupts this
complex, the shoulder is at a greater risk of injury.
Bony Anatomy
The humerus, scapula and the clavicle make up the bony anatomy of the shoulder girdle. The humerus is the largest and longest bone of the upper extremity, with its proximal portion consisting of hlaf-spheriod articulating surface or head, greater tuberosity, bicipital groove, lesser tuberosity and proximal humeral shaft (Terry, 2000).
(FIGURE 1)
Their are three facets on the greater tuberosity where the tendons of the supraspinatus, infraspinatus and terres minor insert. The subscapularis inserts on the lesser tuberosity completing the rotator cuff.
The scapula is a large , thin, triangular bone lying on the posterolateral aspect of the thorax, overlying ribs two through seven, that serves mainly as a site of muscle attachment (Terry, 2000). The scapula is attached to the torso by way of the clavicle. The scapula serves as a lever and pulley for the arm. The muscles acting on the scapula have two purposes. First, they move the scapula and the glenoid fossa so that the arm has increased range of motion. Second, the muscles of the scapula act to fixate the scapula on the thorax to provide the arm with a fixed base of support during isometric contractions.
The clavicle serves as the sole bony strut connexting the trunk to the shoulder girdle via the sternoclavicular joint medially and the acromioclavicular joint laterally (Terry, 2000). The clavicle has mainly three purposes: 1) the clavicle serves as a site for muscle attachments. 2) the clavicle serves as a barrier to protect underlying neurovascular structures. 3) the clavicle serves as a strut to stabilize the shoulder complex and prevent it from displacing medially. Also, the strong coracoclavicular ligaments of the the clavicle prevents inferior migration of the shoulder girdle. The bony anatomy provides a structured foundation from which the forces are generated and acted on.
The rotator cuff is made up of four muscles: subscapularis, supraspinatous, infraspinatus and the teres minor. The rotator cuff with the deltoid place the arm in the overhead position essential in many sports. The rotator cuff muscles work as dynamic stabilizers of the shoulder girdle. The inability to factor in dynamic function of the musculator has been the main criticism of studies done on shoulder stability. In addition, muscles of the rotator cuff, primarily the infraspinatus, ters minor and the subscapularis depress and stabilize the humeral head (Wolin, 1997). The head of the humerus would move upward in the glenoid fossa during arm abduction because of the unopposed pull of the deltoid without help from the rotator cuff. Stability is achieved through three mechanisms:1) joint compression, 2) coordinated contraction of the rotator cuff muscles guiding the humeral head into the glenoid throughout the full range of motion, and 3) glenohumeral ligament dynamization through direct attachment of the rotator cuff (Levine, 2000).
The subscapularis originates from the subscapular fossa and extends laterally to insert on the lesser tuberosity of the humerus. The anterior of the rotator cuff is mafe up of essentially the subscapularis. The subscapularis serves as an internal rotator, especially during maximum internal rotation. The subscapularis is innervated by the upper and lower subscapular nerves.
The supraspinatus originates on the supraspinous fossa and inserts forward and laterally at the superior aspect of the greater tuberosity. The supraspinatus helps stabilize the glenohumeral joint. The supraspinatus along with the deltoid elevate the arm. The supraspinatus in innervated by the suprascapular nerve.
The infraspinatus originates from the infraspinous fossa and extends laterally to insert on the middle facet of the greater tuberosity. The infraspinatus stabilizes the glenohumeral joint against posterior subluxation. The infraspinatus along with the teres minor serve as primary external rotators. The subscapular nerve innervates the infraspinatus.
The teres minor originates from the middle to upper regions of the axillary border of the scapula. It inserts on the most inferior facet of the greater tuberosity. The teres minor also serves as a stabilizer of the glenohumeral joint against posterior subluxation. As noted earlier, the teres minor is also a primary external rotator. The teres minor is innervated by the axillary nerve.
Biomechanics is the effect of muscular forces, joint axis and resistance on the quality and quantity of human movement. Shoulder biomechanics are difficult to understand because the shoulder can move in so many different planes and directions. Many sports involve placing the shoulder joint and its surrounding structures at a high risk of injury. Static limits of glenohumeral motion for all activities are imposed by the geometry of the articular components of the cavity as well as the soft tissue envelope (Meister, 2000). Overhead sports such as swimming, tennis and baseball put an enormous amount of strain on the shoulder. The baseball throwing motion has been studied and provides us with many useful principles that are applicable to other overhead activities. Additionally, the speed with which the action occurs results in the extreme use of dynamic stabilizing structures, increasing their vulnerability to injury (Meister, 2000). A baseball pitcher throws a 142-gram baseball from 0 to 90 miles per hour in 50 milliseconds. This places a large compressive load on shoulder joint. Safe and efficient transfer of energy of this magnitude from the back and lower extremities to the pitching arm to the baseball requires highly complex and synchronous interactions among the trunk and lower extremity muscles (i.e, latissimus dorsi and pectoralis major), intrinsic shoulder muscles (i.e, rotator cuff), and static capsular restraints (Williams & Kelley, 2000).
The overhead throwing motion can be broken down into six phases. These phases are classified by the different mechanics and muscles firing in each phase. From a mechanical prospective, the goal of the motion is to sequentially develop a package of potential energy that is then converted to kinetic energy that can be imparted to the ball in an efficient and fluid manner. In most cases, the more fluid the throwing motion is, the less pressure and strain on the shoulder complex you will have.
Phase 1, the the wind up, is the phase during which the body’s center of gravity is raised with minimal stress impaired to the shoulder. The rotator cuff muscles are inactive during phase one. The shoulder is in minimal internal rotation and abduction at the end of phase one.
Phase 2, early cocking, a slight load phase, the shoulder moves into 90 degrees of abduction and 15 degrees of horizontal abduction. The iniation of this phase is marked by early activation of te deltoid muscle and late activation of the supraspinatus, infraspinatus, and teres minor (Meister, 2000).
Phase 3, late cocking, begins with the stride leg being planted and ends with the shoulder in maximum external rotation, 170 to 180 degrees, the supraspinatus, infraspinatus and teres minor’s muscle activity reaches its peak in the middle of phase three.
Phase 4, acceleration, rotates the shoulder to the ball release point of 90 degrees rotation, maintaining shoulder abduction (Meister, 2000). Early in the phase the triceps have activity, late in phase four, the pectoralis major, latissimus dorsi and serratus anterior have activity.
Phase 5, decleration, which is recognized as the most harmful phase of the throwing cycle is responsible for depletion of the remaining energy. Eccentric contraction takes place by all of the muscle groups to retard arm rotation. The center of gravity moves over the plant foot.
Phase 6, the follow-through, is the phase where the body is rebalancing and the body is moving forward till the motion stops. During the follow-through muscle firing levels return to resting levels.
Throughout the entire pitching motion, the scapula must move synchronously with the humerus to maintain glenohumeral stability (Williams & Kelley, 2000). The entire throwing motion takes approximately two seconds to complete all six phases. The wind-up and cocking phase take up 75% of the time, usually about 1.5 seconds. The accleration phase takes approximately .05 seconds and the decleratoin and the follow-through phases take approximately .35 seconds (Meister, 2000).
Rotator cuff injuries are rarely caused by one etiological factor in overhead athletes. Injury from throwing can occur to any of a number of structures contributing to the dynamic or static restraint of the shoulder (Meister, 2000). Athletes who use overhead throwing motions and develop rotator cuff fatigue, therefore, are at increased risk for developing injury to the anterior glenohumeral ligaments and capsule (Levine & Flatow, 2000). Potential contrbuting factors to rotator cuff injuries in the athlete include tensile failure of the rotator cuff tendon fibers, poor scapular mechanics, rotator cuff imbalance, anterior capsular laxity, posterior capsular contraction and traditional supraspinatus outlet narrowing (Williams & Kelley, 2000). If any of these structures become weak of fatigued more stress is placed on another structure. Most of abnormal biomechanics and overuse injuries that occur about the shoulder girdle can be traced to alterations in the function of the scapular-stabilizing muscles (Voight, 2000). In the shoulder girdle, the most common problem seen is muscle weakness. Weakness of the scapulothoracic muscles potentially leads to abnormal positioning of the scapula, disturbances in the scapulaohumeral rhythm and generalized shoulder dysfunction (Kamkar, 1993). In fact scapular instability is found in as many as 68% of rotator cuff problems and 100% of glenohumeral instability problems (Kibler, 1998). The abnormal scapular biomechanics that occur as a result of dysfunction create abnormal scapular positions that decrease normal shoulder function and predispose the shoulder to injury (Voight, 2000).
Rehabilitation
The goal of athletic rehabilitation is to return the athlete back to
activity. For a successful shoulder rehabilitaiton, one must have a complete
and accurate understanding of the involved tissues. Therefore, a thorough understanding
of the physical demands of the activity is a prerequisite to making a complete
diagnosis and returning the athlete to sage, pain-free participation (McMullen,
2000). The non-operative rehabilitation program used for treatment of shoulder
injuries to the overhead thrower involves a multiphased approach that is progressive
and sequential (Wilk, 2002).
Phase One
The primary goals of the acute phase is to increase flexibility, reestablish baseline dynamic stability, normalize muscle balance, restore proprioreception without causing shoulder pain. To decrease pain and inflammation you need to use modalities such as ice, ultrasound, and electrical stimulation. The athletes activities also need to be modified to a pain-free level. Another essential goal in phase one is to normalize shoulder motion, particularly shoulder internal rotation and horizontal adduction (Wilk, 2002). In most cases of overhead throwers it is normal to see a significant loss of internal rotation due to soft tissue tightness. This tightness may occur from muscle inflexibility due to repetitive eccentric forces during arm deceleration. Increased anterior translation of the humeral head may take place due to tightness of the infraspinatus and teres minor. Therefore, the thrower should perform specific stretches and flexibility exercises for the benefit of the posterior rotator cuff muscles (Wilk, 2002). To improve posterior shoulder flexibility, the horizontally adduction stretch can be performed at 90 degrees of shoulder abduction. To enhance the posterior shoulder stretch the scapula should be stabilized while the arm is horizontally adducted.
Exercises
v Pendulum Exercises- clock-wise, counter clock-wise- 1 to 5 sets of 10-12 reps w/no pain.
v T-Bar exercises- overhead in flexion hold for 5-10 seconds and back to starting position, repeat 5 to 10 times.
v Rope and pulley exericses- 1 to 5 sets of 10. (progressing)
v Isometrics- Adductors, external rotators, internal rotators, elbow flexors, shoulder flexors, 1 to 5 sets held at sub-maximal force for 8 to 15 seconds.
v Surgical tubing- (internal/external rotators) progress, 1 to 5 sets of 10 to 12 reps with no pain.
Criteria to proceed
1. Acieve gradual return to 80-90% range of motion with no pain.
2. Reduction of local symptoms.
3. Acceptable degree of tissue healing to permit therapeutic exercise.
4. We want strength to be at least 60-70%, pre-injury level.
Phase Two
In phase two of rehabilitation, the main goals are to progress the strengthening program, improve flexibility, and facilitate neuromuscular control. During phase two the rehabilitation program is to progress to more aggressive isotonic strengthening activities with the main goal being muscle balance. In the overhead thrower, the shoulder external rotators cuff muscles, scapular retractor muscles and protractor and depressor muscles are frequently isolated because of weakness (Wilk, 2002). Phase two, you want to go deeper into the exercises and maybe do more sets and reps. You still want to work in a pain free enviroment. In phase two, we will still use modalities that we used in phase one.
Exercises
v Active assited T-bar.
1. Flexion to 170-180 degrees with no pain.
2. External-internal rotation performed at 90 degrees shoulder abduction-external rotation to 75-90 degrees, internal rotation 75-85 degrees.
3. External rotation performed at 0 degrees. Hold each for 8 to 10 seconds, 5 sets.
v Isotonic exercises- dumbell exercises for deltoid, supraspinatus, elbow flexors, and scapulae muscles. 1 to 5 sets with 1 to 2lbs., 10-12 reps with no pain.
v Initiate upper body ergometer for endurance.
v Initiate neuromuscular control exercises for scapula.
Criteria to proceed
1. Achieve full range of motion, non-painful.
2. Improve strength to 70-80%.
3. Increase functional activities, reduce residual pain.
Phase Three
In phase three, the advanced strengthening phase, the goals are to initiate aggressive strengthening drills, enhnce power and endurance, perform functional drills, and gradually initiate throwing activities (Wilk, 2002). In this phase we will also incorporate plyometric drills. To enhance propriorection and neuromuscular control we will do dynamic stabilization drills. These drills include push-ups on the ball and throwing the ball against the wall. The initial plyometric program will include two handed drills such as a chest pass, overhead throw, side to side throw, these plyometric drill will incoporate the transfer of energy from the legs and trunk to the upper extremity. Once the athlete has mastered the two handed drills we will progress to just one hand. In phase three, we are trying to work a lot on muscle endurance, especially since one of the main problems in rotator cuff injuries is fatigue. Also in this phase we will incorporate throwing exercises. Initially we will not use a baseball, the athlete will go through the mechanics of throwing the ball in a mirror. The interval program is initiated once the athlete can fulfill these specific criteria: 1)satisfactory clinical examination, 2)nonpainful range of motion, 3) satisfactory isokinetic test results, and 4) appropriate rehabilitation progress Wilk, 2002).
Exercise
v Continue all the exercise listed in the other phases.
v Increase intensity as long as there is no pain.
v Plyometrics, push-ups on the ball, throwing with two hands and progress to one hand.
v Start throwing program. Progress from throwing in fromt of mirror to playing long toss. Make sure of proper mechanics, improper mechanics will just put pressure on another part of the shoulder or elbow.
v Any aquatic activities are also great for phase three.
Criteria to proceed
1. Complete range of motion and 100% strength.
2. Isokinetic testing usually takes place about the 13th week of rehab.
3. Should be able to complete throwing program implemented with no pain.
4. Should be able to throw at 90 to 100% with no pain.
Phase Four
Phase four we are ready to return the athlete to full go. Phase four should include all the exercise pescribed in the previous three phases. In phase four, we also need a doctors release for the athlete to return to activity. The athlete is also instructed to continue the stretching program, core-exercise training, and lower extremity strenthening activities (Wilk, 2002). The athlete should also be counseled on a periodization conditioning program that takes place all year round.
Here are some examples of exercises done for the rotator cuff.
Exercise 1
Start by lying on your stomach on a table or a bed. Put your left arm out at shoulder level with your elbow bent to 90° and your hand down. Keep your elbow bent and slowly raise your left hand. Stop when your hand is level with your shoulder. Lower the hand slowly. Repeat the exercise until your arm is tired. Then do the whole exercise again with your right arm
Exercise 2
Lie on your right side with a rolled-up towel under your right armpit. Stretch your right arm above your head. Keep your left arm at your side with your elbow bent to 90° and the forearm resting against your chest, palm down. Roll your left shoulder out, raising the left forearm until it's level with your shoulder. (Hint: This is like the backhand swing in tennis.) Lower the arm slowly. Repeat the exercise until your arm is tired. Then do the whole exercise again with your right arm.
Exercise 3
Lie on your right side. Keep your left arm along the upper side of your body. Bend your right elbow to 90°. Keep the right forearm resting on the table. Now roll your right shoulder in, raising your right forearm up to your chest. (Hint: This is like the forehand swing in tennis.) Lower the forearm slowly. Repeat the exercise until your arm is tired. Then do the whole exercise again with your left arm
Exercise 4
