A 17-year-old right-hand-dominant male tennis player visited our hospital complaining of pain in the anterior aspect of the right shoulder. Four years before his visit, he had experienced sudden acute pain in the anterior aspect of the right shoulder while executing a forehand stroke. Before the injury, the patient, who was a member of a tennis club at his junior high school and a private tennis club, allowed himself only 1 day of rest each month. Despite the pain, the subject continued to participate in competitive tennis for 4 years and experienced the pain especially during the follow-through phase. The pain increased gradually. One month before his visit to our hospital, he was examined by his family doctor, who advised him to rest his shoulder. However, the pain in his right shoulder persisted even while performing daily activities. Hence, he was then referred to our hospital.
Physical examination revealed tenderness at the lesser tuberosity, with exacerbation of pain by horizontal adduction and/or by internal rotation during the elevation of the humerus. Clinical evaluation of the rotator cuff muscles revealed full muscle strength of the supraspinatus and external rotator muscles. The result of the lift-off test was negative for the subscapularis tendon. The range of motion of the right and left shoulders did not exhibit any differences in forward elevation and external rotation. The range of motion in internal rotation with the arm at the side, internal and external rotations with the arm abducted at 90 degrees, internal rotation with the arm at a 90 degrees flexion, and horizontal flexion were 60, 50, 100, 20, and 100 degrees, respectively. The patient showed negative results for joint laxity test. The results of joint instability tests, such as anterior apprehension and posterior jerk tests, were negative. The results of forced horizontal flexion test was positive. Moreover, the preoperative University of California, Los Angels (UCLA) score was 25.
Plain radiographs (true anteroposterior and scapular views) of the right shoulder did not show any fracture or deformity (Figure 1). He was subsequently examined using magnetic resonance imaging (MRI). The T1-weighted images showed a low-intensity area at the lesser tuberosity, and the T2-weighted images showed a high-intensity area at the subscapularis tendon (Figure 2). Computed tomography (CT) was performed with the arm being elevated and in an internal rotation. Unfortunately, we could not confirm a small bony fragment and lesser tuberosity in the same slice because of the distinct position. However, conventional CT revealed an irregularity and osteosclerotic change at the medial edge of the lesser tuberosity. Three-dimensional CT (3D CT) revealed a small bony fragment located between the humeral head and the scapular glenoid in the position for pain provocation (Figure 3). On the basis of these results, his condition was diagnosed as an avulsion fracture of the lesser tuberosity. However, even though it was an avulsion fracture, we intended to remove the bony fragment, because it was very small and repair the tendon.
In the operating room, the patient was maintained under general anesthesia and placed in the beach-chair position for arthroscopic removal of the fragment. Diagnostic arthroscopy was performed through a standard posterior portal. The articular side of the subscapularis tendon was torn, and an avulsion fracture was identified (Figure 4A). We could not confirm the insertion site of the deep surface of the subscapularis tendon as the fracture site, because the area was very small and covered with fibrocartilage. However, the small bony fragment was originally inserted in the deep surface of the subscapularis tendon. Subsequently, internal rotation of the arm resulted in entrapment of the small bony fragment between the humeral head and the glenoid of the scapula (Figure 4B). The bony fragment was oval and approximately 7 mm in the major axis. The long head of the biceps showed no signs of subluxation or dislocation. No further intra-articular pathological features were detected. After the anterior and anterosuperior portals were established, the small bony fragment was removed (Figure 4C). A Fastin RC suture anchor with a no. 2 Ethibond suture (Mitek, USA) was used and inserted on the side of the fracture via the anterior portal. The 2 threads protruding from the area where the anchor was inserted were introduced through the only deep surface of the subscapularis tendon by the suture relay technique. A mattress suture was then used to repair the subscapularis tendon (Figure 4D). Histological examination of the lesion showed that the avulsed bone fragment was surrounded by fibrocartilage (Figure 5).
The patient’s arm was immobilized at his side in a sling for 2 weeks after the operation. During this period, only passive flexion was permitted. After 2 weeks, active arm exercises were initiated in all planes, ensuring avoidance of provocation of pain. After a month, the patient was almost completely relieved of pain and was able to perform all the daily activities. However, preparation for college entrance examination interrupted his sport activity for a while. He entered college 2 years after the surgery and began playing tennis again at a recreational level. The postoperative range of motion was almost improved, whereas the range of motion in the horizontal flexion remained to be 100 degrees. The postoperative UCLA score also improved to 33.