The tennis athlete is exposed to repetitive overhead activity and is predisposed to overuse injuries about the shoulder (Fig. 23-1). Twenty-four percent of tennis players between 12 and 19 years of age complain of shoulder pain; among middle-aged players, the incidence of shoulder pain increases to 50% (1). In the tennis player, the shoulder girdle is susceptible to injury because it is responsible for both rapidly accelerating and decelerating the upper extremity while both controlling arm rotation and providing a stable scapular platform to enable the player precise control of the racquet for effective ball striking. The weight of the tennis racquet creates a lever arm that adds power to the tennis stroke, but it also increases stresses around the shoulder. The tennis player must be able to harness the high forces required at ball strike while maintaining control and shoulder stability. Although shoulder injuries in the tennis athlete are fairly common, most are easily reversible. Decreasing playing time and carefully prescribed rehabilitation exercises can alleviate most injuries and return tennis athletes of all abilities to their previous levels of play. However, if neglected, certain tendon and ligamentous injuries that initially present as benign can become complex.

Shoulder injuries can develop from muscle fatigue, eccentric overload, instability, and secondary impingement. Repetitive microtrauma initially causes inflammation and tendonitis, which leads to tissue breakdown and progression of altered shoulder mechanics. Because tennis is a highly repetitive sport requiring extensive practice and playing time, minor injuries can become exacerbated by a change in stroke production by a tennis athlete in order to compensate and play through pain and or injury. Eventually, these maladaptions diminish a player’s ability and worsen the original injury. Maladaption is more common in tennis than in other overhead sports such as volleyball or baseball. For one reason, tennis is an individual sport, and for professional athletes, increased injury time directly affects monetary compensation. A second reason lies in the nature of the game of tennis. An experienced player who has sustained a shoulder injury may alter stroke mechanics or even match strategy to compensate for certain deficiencies. Maladaption allows the player to continue to participate, but decreases maximal performance level and eventually exacerbates the original injury.

Areas of injury to the shoulder in the tennis player include soft tissue structures such as ligaments, tendons, and capsulolabral complexes, as well as bone and articular cartilage. Location and severity of injury is most often dependent on player age, but can be related to skill level. Tennis is a sport with an age range of players that spans from adolescents to senior citizens; it is important to consider age of the patient when developing the diagnosis and comprehensive plan for treatment. This chapter identifies common shoulder injuries specific to the tennis athlete and details critically important nonoperative as well as operative measures necessary for the care of these patients.

The glenohumeral joint is a ball and plate construct requiring both static and dynamic stabilizers. The static components consist of the bony architecture of the humeral head and the glenoid, along with the labrum and the glenohumeral ligaments. The congruent surfaces of the humeral head in contact with the glenoid and labrum create a suction effect that increases the stability of the shoulder. This glenohumeral stability is maximized with anatomic positioning. The dynamic stabilizers consist of the rotator cuff muscles and the deltoid and the periscapular musculature. The rotator cuff is a four-muscle tendon complex that works to stabilize the humeral head in the glenoid fossa. The largest segment, the subscapularis, is innervated by the subscapular nerves and inserts on the lesser tuberosity. The supraspinatus, infraspinatus, and teres minor assist in arm elevation and externally rotate the humerus. The rotator cuff muscles center the humeral head on the glenoid during motion. Fatigue of this complex network results in loss of normal concavity compression. The resultant increased
translation of the humeral head on the can lead to plastic deformation of the static stabilizers.

The elite tennis player generates exceptional forces and rotational velocities around the shoulder during play. Ball speed during overhead serve routinely travels between 100 and 120 miles per hour (mph). Rotational velocities as fast as 1,500 degrees/second are achieved in the overhead serve, and 895 and 387 degrees/second have been demonstrated in the backhand and forehand, respectively (2). As a result of these shoulder velocities, hand speed at ball impact has been measured at 47 mph during service, 33 mph during backhand, and 37 mph during forehand strokes (2). Although one does not expect most recreational players to generate such high velocities, the short duration and high intensity forces that must continually be generated from a near static position create extreme stresses across the shoulder joint. As in most sports, the increase in efficiency of force transfer leads to increased performance. Ineffective stabilization of scapulothoracic motion or the glenohumeral joint at ball strike results in compromised efficiency, muscle fatigue, and increased mechanical stresses on the shoulder.

Understanding the mechanics of the common tennis strokes can be helpful in identifying pathology and developing a treatment program. The tennis serve can be broken down into four stages: (a) wind-up, (b) cocking, (c) acceleration, and (d) deceleration/follow-through (3). During the cocking phase of the serve, the subscapularis helps accelerate the arm in internal rotation and adds anterior stability to the humeral head. At overhead ball strike, stability is largely dependent on the labrum and the capsular ligaments. These static stabilizers are at most risk for injury during periods of muscle fatigue and decreased efficiency. During the deceleration phase, stress is then transferred to the supraspinatus. The ground strokes in tennis consist of both the forehand and the backhand. They are the strokes most commonly used and are less likely to directly cause overhead injury, but they do contribute to periscapular muscle fatigue. The ground strokes can be broken down into three phases: (a) racquet preparation, (b) acceleration, and (c) follow-through (4). Studies using electromyographic (EMG) activity have correlated muscle activation with each stage. During the serve and the forehand, the subscapularis, the pectoralis major, and the serratus anterior demonstrate the greatest muscle activation. The backhand uses mostly middle deltoid, supraspinatus, and infraspinatus muscles (4).

During a tennis match, or even a practice, several repetitive motions are performed, each requiring synchronous firing of muscle activity. Multiple force couples constrain glenohumeral translation. An example of a force couple routinely used is between the deltoid, a continual humeral head elevator, working in conjunction with the supraspinatus and the infraspinatus, which are humeral head compressors. Asynchronous firing of injured or fatigued muscles can result in either humeral head elevation or scapular winging evidenced by poor retraction and protraction. The trapezius, serratus anterior, rhomboids, and levator scapularis are all subject to eccentric overload failure. Once the dynamic musculotendinous constraints of the shoulder lose effectiveness, the ligamentous constraints become the primary restraints to excessive humeral head translation.

In the adult tennis player, shoulder injury can occur in a variety of anatomic locations. Although the tennis athlete may present with multiple injuries, the most common injuries are presented here.

Successful treatment of shoulder problems in any athlete is dependent on accurate diagnosis, the first step in either developing an appropriate rehabilitation program or planning a reparative surgical procedure. Most tennis players with shoulder injuries present with pain. After obtaining a detailed history,
the physical examination should begin with inspection of the standing patient. Both shoulders should be evaluated for scapular asymmetry and muscular atrophy. Depression of the dominant shoulder with the appearance of scoliosis is a posture frequently seen in tennis players and has been termed tennis shoulder (6). Tennis shoulder, however, has not yet been correlated with any specific injury. Elite tennis players may also present with atrophy of the biceps and triceps, with hypertrophy of the forearm musculature (1).

Systematic palpation of the cervical spine, shoulder, and upper extremity should follow inspection. The authors recommend beginning with the cervical spine and finishing with the fingertips. It is essential to evaluate range of motion of the cervical spine as well as assess for radiculopathy or myelopathy. A thorough examination includes palpation of the sternoclavicular joint, the clavicle, the AC joint, and the scapula. Shrugging of the scapula is due to weakness of the periscapular stabilizers. This may also be evidenced by a loss of protraction, retraction, or scapular winging (Fig. 23-3). If AC joint tenderness is present, the examiner should assess for tenderness with the arm adducted in a horizontal position. This helps maximize the pressure on the AC joint and exacerbates any potential symptoms (7). The presence of AC joint tenderness could also suggest a possible os acromiale, an unfused acromial epiphysis, and follow-up radiographic studies are needed for corroboration. Depending on the associated pathology, tenderness may be elicited from the long head of the biceps, the deltoid insertion, or the greater tuberosity. Speed’s and Yergason’s tests can be used to evaluate the biceps as a potential cause of pain. Speed’s test is performed by having the patient attempt flexion of the arm with the elbow flexed at 30 degrees and the forearm held in supination. The test is positive if it elicits pain in the bicipital groove. Yergason’s test is considered positive if pain is elicited by resisted supination of the forearm with the elbow flexed.