Examination Under Anesthesia for Evaluation of Anterior Shoulder Instability
Abstract & commentary
Synopsis: Examination under anesthesia is a valuable adjunct to assess shoulder instability and it is important that the shoulder be evaluated in multiple directions.
Source: Oliashirazi A, et al. Examination under anesthesia for evaluation of anterior shoulder instability. Am J Sports Med 1999;27(4):464-468.
For this study, oliashirazi and colleagues chose 30 patients who represented a homogeneous group, all with a diagnosis of recurrent unilateral traumatic anterior shoulder instability. Patients were examined preoperatively in a clinic setting and then evaluated under anesthesia. The purpose of the study was to attempt to correlate the value of an examination under anesthesia with the pathological findings.
The role of rotational position of the arm during the exam was also critically assessed. Oliashirazi et al found that when the affected shoulder was placed in 40°-80° of external rotation, there was a significant increase in the humeral head translation in an antero-inferior direction. A grading system was used as follows: grade I, no abnormal translation; grade II, mild translation up and toward the glenoid rim; grade III, the humeral head has a moderate degree of translation in the glenoid and moves up and onto the glenoid rim; grade IV, the humeral head translation is severe and the head rides up and over the glenoid rim and dislocates.
When Oliashirazi et al compared the affected shoulder to the unaffected shoulder, the test sensitivity was 83% and the test specificity was 100%. Strict criteria were used in that the grade of subluxation or dislocation in the involved shoulder had to measure at least two grades higher than the unaffected side. They concluded that the examination under anesthesia is a valuable adjunct to assess shoulder instability and emphasized the necessity of evaluating it in multiple directions, including straight inferior, straight posterior, straight anterior, anteroinferior, and posteroinferior.
Comment by James P. Tasto, MD
Shoulder instability is a complex issue.1 Cofield and colleagues reported on humeral head translation under anesthesia in a previous article, but because the selected population in that study was not homogeneous, the assessment was not believed to be that valuable.2 There have been a number of studies that have either supported or contradicted the value of evaluation under anesthesia.3,4 Some feel that it is mandatory and quite valuable, while others feel that it has no particular merit.
We have found that it is a difficult physical examination skill to teach as well as to perform. One must do repetitive examinations, not only on patients with pathological conditions but also on normal shoulders, as there is a wide variety of physical findings, particularly with those patients who have inherent general overall laxity.
The evaluation under anesthesia serves as a great adjunct to one’s evaluation in the office to try to correlate those findings and also to refine one’s technique. I have found, as have Oliashirazi et al, that early on most physicians will attempt to apply too great a force to the shoulder and will not appreciate the instability pattern. A light force is all that is required with varying degrees of rotation. Oliashirazi et al describe performing a variety of tests in a supine position, comparing both shoulders. I would also recommend learning to do a shoulder exam both with the patient in the supine position, comparing both shoulders, and in the decubitus position with the affected shoulder facing upward and the patient’s back and torso resting comfortably against the examiner. This has the added advantage of allowing the patient to relax more and has proved to have more reproducible and consistent results in my hands. For those sports physicians who are not orthopedic surgeons, I would encourage you to spend some time in the operating room with your colleagues and refine your skills so you will be prepared to perform these tests in the clinical setting.
References
1. Rockwood CA Jr, Wirth MA. Subluxations and dislocations about the glenohumeral joint. In: Rockwood CA, et al, eds. Rockwood and Green’s Fractures in Adults. 4th ed. Philadelphia: Lippincott-Raven; 1996: 1193-1339.
2. Cofield RH, et al. Diagnosis of shoulder instability by examination under anesthesia. Clin Orthop 1993; 291:45-53.
3. Neer CS II, Foster CR. Inferior capsular shift for involuntary inferior and multidirectional instability of the shoulder. A preliminary report. J Bone Joint Surg Am 1980;62:897-908.
4. Craig EV, et al. Decision making: A recurrent shoulder instability. In: Warren RF, et al, eds. The Unstable Shoulder. Philadelphia: Lippincott-Raven; 1999: 189-204.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content