Drs Owens and Cameron are from Keller Army Hospital, West Point, New York; Ms Duffey is from the Department of Kinesiology, The Pennsylvania State University, State College, Pennsylvania; and Dr DeBerardino is from the Department of Orthopedic Surgery, University of Connecticut Health Center, Farmington, Connecticut.
Drs Owens, DeBerardino, and Cameron, and Ms Duffey have no relevant financial relationships to disclose. This project was aided by a grant from the Orthopaedic Research and Education Foundation.
The views and opinions expressed in this article are those of the authors and do not reflect the official policy of the Department of the Army, Department of Defense, or United States government.
Correspondence should be addressed to: Brett D. Owens, MD, Keller Army Hospital, 900 Washington Rd, West Point, NY 10996 (email@example.com).
Instability of the glenohumeral joint is common,1 with young athletes and military personnel most at risk.2–4 Glenohumeral instability events result in significant time lost to sport and frequently require surgical stabilization.2,4 Despite the impact of this injury, little is known of the risk factors for injury.
The physical examination findings for patients with shoulder instability have been evaluated.5 However, less is known of the examination findings in a healthy cohort.6,7 It is important to establish the normal spectrum of physical examination findings in a healthy cohort to plan and conduct epidemiologic research on shoulder injuries such as instability.
As part of a longitudinal prospective cohort study to evaluate risk factors for glenohumeral instability, baseline physical examination of the shoulder was performed on a healthy cohort. The goal of this study was to evaluate these physical examination findings for potential correlations with sex and history of shoulder instability on baseline questionnaire. We hypothesized that asymptomatic, healthy patients would have normal physical examination findings, including patients with a history of previous glenohumeral instability.
Materials and Methods
A prospective closed cohort study was initiated to identify the modifiable and nonmodifiable risk factors for shoulder instability within a young, healthy, and physically active population of military cadets. Patients were enrolled into the cohort on arrival to summer training at a collegiate level military academy in July 2006. Baseline physical examination data were collected between July 1, 2006, and October 31, 2006. As part of this broader longitudinal cohort study, this project represents the cross-sectional analysis of the baseline data obtained. The Institutional Review Board at our institution reviewed and approved this study prior to initiation.
The parent study is a prospective cohort study of volunteers at a 4-year collegiate-level military academy. An overview of the methods of this study has been previously described.8 A total of 711 patients completed the baseline data assessment and made up the study cohort. Men made up 88% of our cohort (627 patients) and women 12% (84 patients), which is consistent with the overall student population at our institution, which annually enrolls a freshman class where men represent approximately 85% of each class and women represent the remaining 15%.
Male patients had an average age of 18.8±1.0 years, an average height of 178.5±7.5 cm, and an average weight of 76.1±12.9 kg. Female patients had an average age of 18.7±0.9 years, an average height of 165.4±7.0 cm, and an average weight of 63.2±9.1 kg. All patients were deemed healthy and medically fit for military service prior to admission to the academy through a standardized pre-service medical evaluation system.
Physical Examination. A physical examination focused on shoulder instability was performed on both shoulders of all patients. All examinations were performed by a single sports medicine fellowship-trained orthopedic surgeon (B.D.O.) blinded to the results of injury history from the baseline questionnaire. The examination consisted of a load-shift (anterior, posterior, inferior) maneuver, anterior apprehension sign, relocation testing, sulcus sign, scapular dyskinesis, and ligamentous laxity.
The load-shift maneuver was performed with the patient in the supine position.9 The amount of glenohumeral translation in the anterior, posterior, and inferior directions were graded using the McFarland grading system: grade I, minimal translation within the glenoid fossa; and grade II, to the rim and dislocated.6,7 The apprehension test was performed with the patient in the supine position with 90° of abduction and external rotation. A positive test was the expression of apprehension or pain from the patient in this position.10 The relocation test was then performed in the same position by adding the application of a posteriorly directed force on the proximal humeral head. A positive test was elicited if the relief of apprehension was noted by the patient.11 The sulcus test12 was performed with the patient standing and was graded as present or absent. Scapula dyskinesis was noted and graded according to Kibler’s classification scheme.13 Due to the small number of dyskinetic patients, all dyskinetic patterns were combined to allow for dichotimization and subsequent analysis. Ligamentous laxity was evaluated with a 9-point modified Beighton score.14
History of Shoulder Instability. A primary outcome measure of this study was a self-reported history of shoulder instability prior to arrival at our institution, obtained by questionnaire.8 Shoulder instability was defined as a traumatic event where the humeral head was displaced from the glenoid cavity, requiring manual reduction by a health care provider.4 The 2 items specifically used to identify prior shoulder instability were as follows:
Have you ever dislocated (needed to have put back into place) either shoulder?
Have you ever had a shoulder subluxation (shifts out of place but does not need to be put back in position)?
Frequencies were calculated for each individual physical examination finding among sex groups and among those with a positive history of shoulder instability. The univariate associations between sex, history of instability, and each physical examination variable were assessed using the chi-squared and Fisher’s exact test as appropriate. Odds ratios were calculated to estimate the strength of association between variables of interest and 95% confidence intervals (CIs) were calculated to assess the precision of these estimates. Data analysis was conducted using StataSE version 10.1 (StataCorp, College Station, Texas).
A total of 711 patients included 627 men and 84 women with a mean age of 18.8 years. Of these, only 1 had grade II anterior translation in his dominant shoulder, while 2 had grade II anterior translation in their nondominant shoulders. Nine had grade II posterior translation in their dominant extremity; 9 had grade II posterior translation in their nondominant shoulder. One had grade II inferior translation in his dominant side compared with 2 in their nondominant shoulders. A total of 23 individuals had anterior apprehension in their dominant shoulders compared with 18 in their nondominant shoulders. Of these, 15 of the dominant and 16 of the non-dominant shoulders had relief with relocation testing. Of the 711, thirty-eight had a sulcus sign in their dominant shoulder compared with 41 in their non-dominant shoulder. Of the 711, eight had scapular dyskinesis in their dominant shoulder (5 type I, 1 type II, 2 type III) and 13 in their nondominant shoulders (9 type I, 2 type II, 2 type III). The mean Beighton score was 0.34, with 78.4% of patients having a score of zero.8
Women were 13 times more likely to have increased posterior translation for both the dominant (odds ratio [OR], 13.14; CI, 3.08–56.05; P<.001) and non-dominant (OR, 13.17; CI, 3.09–56.23; P<.001) sides. Patients with a total Beighton score ≥2 were 17.47 times more likely to have grade II posterior translation for both the dominant (OR, 17.47; CI, 4.21–72.57; P<.001) and nondominant (OR, 17.53; CI, 4.22–72.79; P<.001) sides. Patients with grade II posterior translation in their dominant shoulder were more likely to have a sulcus sign in their dominant shoulder (OR, 41.81; CI, 8.32–264.93; P<.001), while patients with grade II posterior translation in their nondominant shoulder had a similarly increased likelihood of a positive sulcus in their nondominant shoulder (OR, 38.17; CI, 7.64–241.38; P<.001). Patients with a Beighton score ≥2 were more likely to have a positive sulcus sign on their nondominant (OR, 7.57; CI, 3.11–17.28; P<.001) and dominant shoulders (OR, 5.01; CI, 1.84–12.26; P<.001).
A total of 100 patients had a history of shoulder instability, with 611 patients reporting no such history. Patients with a history of instability were 6 times more likely to have grade II posterior translation for both the dominant side (OR, 6.10; CI, 1.55–24.00; P=.010) and nondominant (OR, 6.12; CI, 1.56–24.08; P=.010) side. Patients with a history of instability were nearly 4 times more likely to have both a positive apprehension sign for the dominant side (OR, 3.80; CI, 1.62–8.93; P=.003) as well as a positive relocation sign for the dominant side (OR, 4.08; CI, 1.48–11.22; P=.007). Also, patients with a positive history were more likely to have a sulcus on their nondominant shoulder (OR, 3.08; CI, 1.09–7.62; P=.017) but not their dominant shoulder (OR, 1.82; CI, 0.60- 4.63; P=.251).
This study demonstrates a correlation of specific physical examination findings with both sex and a history of shoulder instability in a cohort of asymptomatic young athletes. Patients with a history of instability were more likely to have positive apprehension and relocation signs. One striking finding is the small numbers of patients who had any abnormal physical findings on examination. This may be due to the select nature of our cohort, which has been medically screened for admission to our institution.
We also noted that history of instability correlated with an increase in posterior translation and a positive sulcus sign. Increased posterior translation and a positive sulcus sign were also associated with ligamentous laxity (elevated Beighton score), which has been previously shown to correlate with a history of shoulder instability.8 These findings are not surprising given that these physical examination findings are common in patients with ligamentous laxity and glenohumeral instability.
McFarland et al7 performed a similar study of asymptomatic high school and collegiate athletes as part of preparticipation screening examinations. They found a high (55%) rate of grade II glenohumeral translation in the posterior direction, but do not mention translation anteriorly. They also evaluated inferior translation with a graded sulcus sign, with 52% being grade II and 5% grade III. They also found a higher rate of both increased posterior translation and inferior translation in female athletes (31% of the tested cohort).7 Our findings are consistent regarding the role of sex and the relationship between posterior translation and inferior translation by sulcus sign. However, we found fewer patients having grade II posterior translation. Possible reasons for this disparity are the younger aged cohort studied by McFarland et al,7 the higher proportion of female patients, and differences in subjective grading by the examiners.
Lintner et al6 reported the physical examination findings of 76 collegiate athletes and found grade 2 (Hawkins) translation in 21% of shoulders anteriorly, 54% posteriorly, and 9% inferiorly, with no shoulder translatable over the rim (grade 3 Hawkins classification). We did not find as many patients with humeral head translation over the rim. This may be attributable to the sex variability between these studies, with the Lintner cohort comprising 58% women compared with our cohort at 12%. Another explanation may be the selected nature of our cohort, which has been shown to have a low rate of ligamentous laxity.8
Farber et al5 reported the examination findings of 363 patients undergoing shoulder arthroscopy, 46 of whom had traumatic anterior shoulder instability. They found the apprehension sign to be 72% sensitive but 96% specific and the relocation test to be 81% sensitive and 92% specific for anterior shoulder instability. An anterior drawer test resulting in grade II or III laxity was 60% sensitive and 74% specific. These findings suggest that our correlation of apprehension and relocation in patients with a history of instability should be expected, although the disparity of our study’s population to that of Farber et al5 precludes any direct comparison.
The major limitation to our study is that the patients’ history of shoulder instability does not include objective documentation of injury and may be subject to recall bias. However, the subjective history obtained in our cohort is similar to the previous work at our institution showing a high proportion of subluxation events (Table). This cohort is currently under surveillance for shoulder instability events in a prospective fashion within our closed health care system, and these prospective data may be more reliable. The strengths of our study include the large number of young athletes tested and a consistent physical examination performed by a blinded examiner.
Table: Comparison of Subjective History of Glenohumeral Instability in Young Athletes
We found that healthy patients with a history of shoulder instability had specific physical examination findings suggestive of instability, including anterior apprehension and relocation testing. Regardless, the vast majority of our young, healthy patients had few abnormal physical examination findings.
- Zacchilli MA, Owens BD. Epidemiology of shoulder dislocations presenting to emergency departments in the United States. J Bone Joint Surg Am. 2010; 92(3):542–549. doi:10.2106/JBJS.I.00450 [CrossRef]
- Owens BD, Agel J, Mountcastle SB, Cameron KL, Nelson BJ. Incidence of glenohumeral instability in collegiate athletics [published online ahead of print June 25, 2009]. Am J Sports Med. 2009; 37(9):1750–1754. doi:10.1177/0363546509334591 [CrossRef]
- Owens BD, Dawson L, Burks R, Cameron KL. Incidence of shoulder dislocation in the United States military: demographic considerations from a high-risk population. J Bone Joint Surg Am. 2009; 91(4):791–796. doi:10.2106/JBJS.H.00514 [CrossRef]
- Owens BD, Duffey ML, Nelson BJ, DeBerardino TM, Taylor DC, Mountcastle SB. The incidence and characteristics of shoulder instability at the United States Military Academy. Am J Sports Med. 2007; 35(7):1168–1173. doi:10.1177/0363546506295179 [CrossRef]
- Farber AJ, Castillo R, Clough M, Bahk M, McFarland EG. Clinical assessment of three common tests for traumatic anterior shoulder instability. J Bone Joint Surg Am. 2006; 88(7):1467–1474. doi:10.2106/JBJS.E.00594 [CrossRef]
- Lintner SA, Levy A, Kenter K, Speer KP. Glenohumeral translation in the asymptomatic athlete’s shoulder and its relationship to other clinically measurable anthropometric variables. Am J Sports Med. 1996; 24(6):716–720. doi:10.1177/036354659602400603 [CrossRef]
- McFarland EG, Campbell G, McDowell J. Posterior shoulder laxity in asymptomatic athletes. Am J Sports Med. 1996; 24(4):468–471. doi:10.1177/036354659602400410 [CrossRef]
- Cameron KL, Duffey ML, DeBerardino TM, Stoneman PD, Jones CJ, Owens BD. Association of generalized joint hypermobility with a history of glenohumeral joint instability. J Athl Train. 2010; 45(3):253–258. doi:10.4085/1062-6050-45.3.253 [CrossRef]
- Silliman JF, Hawkins RJ. Classification and physical diagnosis of instability of the shoulder. Clin Orthop Relat Res. 1993; (291):7–19.
- Rowe CR, Zarins B. Recurrent transient subluxation of the shoulder. J Bone Joint Surg Am. 1981; 63(6):863–872.
- Jobe FW, Kvitne RS, Giangarra CE. Shoulder pain in the overhand or throwing athlete. The relationship of anterior instability and rotator cuff impingement. Orthop Rev. 1989; 18(9):963–975.
- 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(6):897–908.
- Kibler WB, McMullen J. Scapular dyskinesis and its relation to shoulder pain. J Am Acad Orthop Surg. 2003; 11(2):142–151.
- Juul-Kristensen B, Røgind H, Jensen DV, Remvig L. Inter-examiner reproducibility of tests and criteria for generalized joint hypermobility and benign joint hypermobility syndrome [publishd online ahead of print November 15, 2007]. Rheumatology (Oxford). 2007; 46(12):1835–1841. doi:10.1093/rheumatology/kem290 [CrossRef]
Comparison of Subjective History of Glenohumeral Instability in Young Athletes
|History of Instability||%|
|Owens et al, 20074||Present Study|
|Type of Event|
| Dislocation & subluxation||13||12|
|Mechanism of injury|
| Noncontact & unknown||56||54|
|Direction of instability|