EVALUATING SPECIFIC SHOULDER PROBLEMS
Rotator cuff abnormalities. Rotator cuff degeneration is a normal consequence of aging. Tendinitis of the rotator cuff will occur in most persons at least once in their lives.
There are 2 ways to tear the rotator cuff: trauma and an attritional process. The latter is similar to "wearing a hole in the seat of your pants"; the tear occurs gradually and insidiously without the patient being aware of it. Partial and even full-thickness tearing of the rotator cuff as a result of this insidious wear is common, and the incidence increases with age.11-13
Many of these rotator cuff tears are asymptomatic and do not require management. A patient with insidious onset of pain who is found to have a rotator cuff tear (either partial or full) probably aggravated a preexisting abnormal (or torn) rotator cuff tendon.
The rotator cuff is not needed for good shoulder range of motion. One study has shown that anesthetizing the suprascapular nerve, which innervates the supraspinatus and infraspinatus muscles, does not preclude full arm elevation.14 The main finding in patients who have a full-thickness rotator cuff tear is weakness in abduction and in external rotation. However, even patients with long-standing rotator cuff disease who have learned to compensate by using the deltoid muscle may have full range of motion and may show only mild to moderate weakness on examination.
Therefore, as recent studies have shown, the most important tests in the examination of patients for rotator cuff problems are those of strength and motion.5,15 The drop arm test, one of the most diagnostic tests for a full-thickness rotator cuff tear,16 is performed in 1 of 2 ways: ask the patient to raise his or her arm to full elevation and then to bring the arm down slowly (if he cannot maintain this slow descent against gravity, he may have a rotator cuff tear or weakness of any cause) or ask the patient to elevate the arm to 90 degrees and then hold it there (Figures 2 and 3). If the patient cannot maintain that elevation, consider the diagnosis to be a rotator cuff tear or weakness of any cause.
Weakness, especially in external rotation or abduction, is another important physical finding that indicates full-thickness rotator cuff tears. Testing of strength in external rotation is accomplished by having the patient place his arms at his sides with the elbows bent 90 degrees. The examiner pushes against the patient's wrists (Figure 4). Weakness in the patient's resistance indicates some process affecting the infraspinatus muscle. However, such weakness may result from pain alone, cervical disk disease, or injury to the infraspinatus nerve by synovial cysts. Studies have shown this test to be sensitive, but not specific, for rotator cuff tears.5
In the past, it was suggested that testing for supraspinatus strength be performed in the "empty can" position (the patient's arms abducted 90 degrees, elbows extended, and arms internally rotated) (Figure 5).9 However, it now appears that this test is equally effective with the arms in neutral or with the thumbs up (the "full can" position).17 This finding is important because the thumbs-down position tends to be painful and may provide false-positive results caused by pain. In addition, the supraspinatus strength test assesses not only the supraspinatus but also the deltoid muscle.17 As a result, some patients with a strong deltoid muscle may have good strength with resisted abduction despite having a torn rotator cuff.
1. McCallister WV, Parsons IM, Titelman RM, Matsen FA 3rd. Open rotator cuff repair without acromioplasty. J Bone Joint Surg Am. 2005;87:1278-1283.
2. Voloshin I, Gelinas J, Maloney MD, et al. Proin-flammatory cytokines and metalloproteases are ex-pressed in the subacromial bursa in patients with rotator cuff disease. Arthroscopy. 2005;21:1076.
3. Yuan J, Wang MX, Murrell GA. Cell death and tendinopathy. Clin Sports Med. 2003;22:693-701.
4. Budoff JE, Rodin D, Ochiai D, Nirschl RP. Arthroscopic rotator cuff debridement without decompression for the treatment of tendinosis. Arthroscopy. 2005;21:1081-1089.
5. Park HB, Yokota A, Gill HS, et al. Diagnostic ac-curacy of clinical tests for the different degrees of subacromial impingement syndrome. J Bone Joint Surg. 2005;87A:1446-1455.
6. Chronopoulos E, Kim TK, Park HB, et al. Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. Am J Sports Med. 2004;32: 655-661.
7. McFarland EG, Kim TK. Examination of the Shoulder: The Complete Guide. New York: Thieme. In press.
8. Krishnan SG, Hawkins RJ, Bokor DJ. Clinical evaluation of shoulder problems. In: Rockwood CA Jr, Matsen FA 3rd, Wirth MA, Lippitt SB, eds. The Shoulder. 3rd ed. Philadelphia: WB Saunders; 2004: 145-185.
9. McFarland EG, Shaffer B, Glousman RE, et al. Anterior shoulder instability, impingement, and rotator cuff tear. Section B: Clinical and diagnostic evaluation. In: Jobe FW, ed. Operative Techniques in Upper Extremity Sports Injuries. St Louis: Mosby-Year Book Inc; 1996:177-190.
10. Harvey RA, Trabulsy ME, Roe L. Are postreduction anteroposterior and scapular Y views useful in anterior shoulder dislocations? Am J Emerg Med. 1992;10:149-151.
11. Brewer BJ. Aging of the rotator cuff. Am J Sports Med. 1979;7:102-110.
12. Milgrom C, Schaffler M, Gilbert S, Van Holsbeeck M. Rotator-cuff changes in asymptomatic adults. The effect of age, hand dominance and gender. J Bone Joint Surg Br. 1995;77:296-298.
13. Tempelhof S, Rupp S, Seil R. Age-related prevalence of rotator cuff tears in asymptomatic shoulders. J Shoulder Elbow Surg. 1999;8:296-299.
14. Colachis SC Jr, Strohm BR. Effect of suprascapular and axillary nerve blocks on muscle force in upper extremity. Arch Phys Med Rehabil. 1971;52:22-29.
15. Murrell GA, Walton JR. Diagnosis of rotator cufftears [published correction appears in Lancet. 2001;357:1452]. Lancet. 2001;357:769-770.
16. Codman EA. Rupture of the supraspinatus ten-don. In: The Shoulder: Rupture of the Supraspinatus Tendon and Other Lesions in or About the Subacromial Bursa. Boston: Thomas Todd Co; 1934:123-177.
17. Kelly BT, Kadrmas WR, Speer KP. The manual muscle examination for rotator cuff strength. An electromyographic investigation. Am J Sports Med. 1996;24:581-588.
18. Neer CS 2nd. Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. J Bone Joint Surg Am. 1972;54: 41-50.
19. Neer CS 2nd. Impingement lesions. Clin Orthop Relat Res. 1983;173:70-77.
20. Hawkins RJ, Kennedy JC. Impingement syndrome in athletes. Am J Sports Med. 1980;8:151-158.
21. O'Brien SJ, Pagnani MJ, Fealy S, et al. The active compression test: a new and effective test for diagnosing labral tears and acromioclavicular joint abnormality. Am J Sports Med. 1998;26:610-613.
22. Stein BE, Wiater JM, Pfaff HC, et al. Detection of acromioclavicular joint pathology in asymptomatic shoulders with magnetic resonance imaging. J Shoulder Elbow Surg. 2001;10:204-208.