Rockwood Adults CH34

1072

SECTION TWO • Upper Extremity

A, B

C

Figure 34-11.  A: The posterior jerk test is done in the sitting position with an axial force applied to the arm in 90 degrees of abduction and maximal internal rotation. B: The arm is then horizontally adducted with the scapula stabilized while the axial load is maintained. C: A feeling of a clunk or jerk elicited with or without pain is considered a positive test. This patient’s humeral head dislocated posteriorly with the above maneuver and then self-reduced with the arm back in the neutral position.

evaluated the painful jerk test as a predictor of success in non- operative treatment of posteroinferior shoulder instability. In the subgroup of patients with both pain and a clunk, they found a significantly higher failure rate after conservative management than the group that did not have pain. Overall, in the painless jerk group, 93% of the patients responded to an intense reha- bilitation program after a mean of 4 months compared to 16% of patients in the painful jerk group that responded to the same program. 120 Occasionally, patients will demonstrate an active jerk test. Sim- ilarly, another apprehension-inducing provocative test involves placing the arm in the position of internal rotation, forward flex- ion, and adduction which will create a condition in which the dynamic stabilizers (posterior rotator cuff muscles) are turned off, and the force vector of the proximal humerus directs posterior to the glenoid, resulting in loading of the static posterior stabilizing structures of the glenoid (labrum, capsule, and ligaments). The addition of a downward force to the arm potentiates the feeling of apprehension and pain. Comparing the pain and response of the patient to the alternative position of the arm in an external rota- tion and abduction in the plane of the scapula should diminish the symptoms of apprehension and pain by allowing the dynamic posterior shoulder stabilizers of the posterior deltoid and rota- tor cuff to be active and the force vector to point at the glenoid. Pain and discomfort is still likely to be present but at a reduced amount compared with the previous position. Posterior load and shift examination and posterior drawer testing are also useful adjuncts for testing of posterior instability. Assessment of patients with possible MDI starts with inspec- tion, palpation, and ROM assessment, with comparison to the contralateral shoulder. 139 Assessment of motion should begin with observing active ROM. Patients will frequently have a supraphysiologic ROM in all planes about the shoulder. Sca- pulothoracic motion along with possible winging should also be evaluated, necessitating the physician to have an unob- structed view of the patient’s shoulder girdle, while still respect- ing patient’s modesty. At our institution, we utilize disposable

paper shorts which have been modified to allow female patients to wear it in the style of a tube top, allowing the clinician to observe shoulder and scapular motion unimpeded (Fig. 34-12). The Beighton hypermobility score should be assessed on every patient with suspected MDI, consisting of examination of passive dorsiflexion of the small finger metacarpophalan- geal joint (MCPJ) greater than 90 degrees, passive dorsiflexion of the bilateral thumbs to the volar forearms (Fig. 34-13A), hyperextension of the bilateral elbows greater than 10 degrees (Fig. 34-13B), hyperextension of the bilateral knees greater than 10 degrees, and the ability for the patient to rest the palms flat on the floor with forward flexion of the trunk and knees fully extended (Table 34-1). 16

TABLE 34-1. Beighton Score for Hyperlaxity

Joint

Positive Finding

Passive dorsiflexion > 90 degrees (Left = 1 point and right = 1 point)

Small finger metacarpophalangeal joint (bilateral)

Thumb (bilateral)

Passive dorsiflexion to the volar forearm (Left = 1 point and right = 1 point) Hyperextension > 10 degrees (Left = 1 point and right = 1 point) Hyperextension > 10 degrees (Left = 1 point and right = 1 point) Forward flexion with knees fully extended results in palms resting flat on the floor (Positive finding is 1 point)

Elbow (bilateral)

Knee (bilateral)

Trunk

Total score

9 Points

One point is given to each side for a positive finding. The maximal total score is 9. Any adult patient with > 5/9 positive findings is considered hypermobile and any children with > 6/9 fits the definition of hypermobile.