The supine moving apprehension test-Reliability and validity among healthy individuals and patients with anterior shoulder instability.

Background: Performance-based tests for patients with anterior shoulder dislocation are lacking. This study determined the reliability and validity of the supine moving apprehension test designed to assess the ability to control anterior instability loads. Methods: Thirty-six participants were recruited (18 healthy individuals, and 18 patients following anterior shoulder dislocation). Healthy participants performed the supine moving apprehension test on 2 separate occasions to determine test-retest reliability. Patients completed the supine moving apprehension test and the Western Ontario Shoulder Instability index before and 6 months after surgical stabilization of their shoulder. The presence of anterior apprehension was also documented post-operatively. Results: The supine moving apprehension test demonstrated good test-retest reliability (intraclass correlation coefficient = 0.74-0.84). Patients performed 18-30 repetitions less than healthy individuals during the supine moving apprehension test (P < 0.01). A strong correlation was found between supine moving apprehension test scores and Western Ontario Shoulder Instability post-operatively (r = -0.74, P ≤ 0.01). Supine moving apprehension test scores significantly improved among patients following surgery (P < 0.01). Patients with a negative apprehension test post-operatively performed the supine moving apprehension test significantly better than patients with a positive apprehension test (P < 0.01). Conclusions: The supine moving apprehension test is reliable and valid among patients with anterior shoulder dislocation and may serve to assess patients' ability to control shoulder anterior instability loads.

Line Hops and Side Hold Rotation Tests Load Both Anterior and Posterior Shoulder: A Biomechanical Study.

BACKGROUND: Clinical tests should replicate the stressful positions encountered during sport participation. Evaluating the kinetic and electromyographical demands of clinical tests enables clinicians to choose appropriate tests for specific sports. PURPOSE: To describe the shoulder forces and muscle activation levels during closed chain functional tests of Line Hops (LH) and Side Hold Rotation (SHR). STUDY DESIGN: Descriptive biomechanical study. METHODS: Ten asymptomatic participants were examined in a university laboratory. Two functional tests were evaluated using three-dimensional video analysis and electromyography to measure shoulder forces, moments, and muscular activity levels. RESULTS: SHR produced a peak average posterior translation force of 4.84 N/kg (CI95 4.32-5.36N/kg) and a peak average anterior translational force of 1.57 N/kg (CI95 1.10-2.01N/kg). High levels of serratus anterior (98% maximum voluntary isometric contraction (MVIC) and infraspinatus (52 %MVIC) were recorded during SHR. LH produced a posterior translational force of 4.25 N/kg (CI95 3.44-5.06N/kg). High levels of serratus anterior (105 %MVIC) and infraspinatus (87 %MVIC) were recorded during the push off phase of this activity. CONCLUSIONS: LH and SHR placed large posterior translational forces that approached half of a person's bodyweight on shoulder structures. SHR produced an anterior translation force at extremes of horizontal abduction placing approximately 18% of bodyweight on shoulder structures. The LH test required the serratus anterior to provide power to push the upper torso of the ground while both the serratus and the infraspinatus provides scapular and humeral stability, respectively. LEVEL OF EVIDENCE: 4: Case series.

Who will redislocate his/her shoulder? Predicting recurrent instability following a first traumatic anterior shoulder dislocation.

OBJECTIVE: To develop a multivariate tool that would predict recurrent instability after a first-time traumatic anterior shoulder dislocation. METHODS: Participants (aged 16-40 years) were recruited across New Zealand into a prospective cohort study. Baseline data were collected during a telephone interview and through examination of radiology records. Variables associated with recurrent instability were selected for the multivariate logistic regression model using backwards selection (p<0.10). Coefficients for those variables retained in the model were used to develop the predictive tool. RESULTS: Among the 128 participants, 36% had redislocated at least once in the first 12 months. Univariate analysis showed an increased likelihood of recurrent dislocation with bony Bankart lesions (OR=3.65, 95% CI 1.05 to 12.70, p=0.04) and participants who had: not been immobilised in a sling (OR = 0.38, 95% CI 0.15 to 0.98, p=0.05), higher levels of shoulder activity (OR=1.13, 95% CI 1.01 to 1.27, p=0.03), higher levels of pain and disability (OR=1.03, 95% CI 1.01 to 1.06, p=0.02), higher levels of fear of reinjury (OR=1.12, 95% CI 1.01 to 1.26, p=0.04) and decreased quality of life (OR=1.01, 95% CI 1.00 to 1.02, p=0.05). There was no significant difference in those with non-dominant compared with dominant shoulder dislocations (p=0.10) or in those aged 16-25 years compared with 26-40 years (p=0.07). CONCLUSION: Six of seven physical and psychosocial factors can be used to predict recurrent shoulder instability following a first-time traumatic anterior shoulder dislocation.