Scapular Dyskinesis 资料 In-depth

This section goes further than you need for your own treatment decisions. Scapular dyskinesis is worth the extra reading because it is so often misunderstood: it is common in people with no symptoms, it rarely explains a shoulder problem on its own, and after shoulder surgery it improves more slowly than the shoulder itself.

A sign, not a diagnosis

The international "scapular summit" consensus describes scapular dyskinesis as an alteration in the resting position or movement of the shoulder blade, present in a high proportion of shoulder injuries. It also concludes that its exact role in causing or worsening shoulder problems is not clearly defined, and that it is best seen as a possible impairment of shoulder function rather than a diagnosis [1]. An earlier review called it a non-specific response to a painful shoulder rather than a feature of any one condition [2].

It is also common without symptoms. Across 12 studies of 1,401 athletes, it was reported in 61% of overhead athletes and 33% of others [3]. Whether it predicts injury is doubtful: in a meta-analysis of 923 athletes followed prospectively, it was present in 46%, and it did not significantly raise the risk of a later shoulder injury (risk ratio 1.07, 95% CI 0.85 to 1.34) [4].

How it is assessed, and the limits of the tests

The usual clinical test is to watch the shoulder blade from behind while the person lifts and lowers the arms several times, often holding light weights, and to grade the movement as normal or abnormal [5]. Agreement between examiners is moderate to good: in 40 patients with impingement, the kappa between two raters was 0.59 (86% agreement). In the same study, people with and without dyskinesis did not differ in their shoulder scores at baseline or at three months [6]. This is why surgeons treat a positive test as one piece of the examination, not a diagnosis.

Winging from a nerve injury is a separate problem. In 96 patients with winging from weakness of serratus anterior proven on nerve testing, 88% had a long thoracic nerve lesion, most often from neuralgic amyotrophy (47) or trauma (33). Of those with neuralgic amyotrophy, 22 recovered without treatment within three years, but none recovered fully once the winging had lasted longer than three years [7].

Rotator cuff tears: cause or consequence?

A systematic review of 16 studies (335 tears) found that the shoulder blade moves abnormally in every study of cuff tears, but with no consistent pattern. Larger tears showed more change, and painful tears more than painless ones; painless tears did not differ from healthy shoulders. The review could not say which changes are adaptive and which are harmful [8]. One comparison found less upward rotation of the shoulder blade, and more work from levator scapulae, in painful tears than in painless ones, with upper trapezius more active than in healthy shoulders [9]. In massive tears that regained movement with physiotherapy, PET scans showed the levator scapulae and rhomboids working harder, consistent with the shoulder blade muscles compensating for the cuff [10].

What happens after rotator cuff repair

The studies disagree, and that disagreement is the main message.

• It often improves. In 35 patients assessed with CT before and after repair, 23 (66%) had dyskinesis beforehand. 12 of the 23 improved after surgery, mostly the type with reduced backward tilt. Improvement went with better forward elevation and Constant scores, and no repair failed to heal in the improved group [11].
• It can normalise. In 26 patients tracked with electromagnetic sensors for a year, shoulder blade movement moved towards the pattern of the other shoulder, and abduction improved by 20° [12].
• It can persist. In 21 patients measured with wearable sensors at 12 months or more, movement and Constant scores improved, but shoulder blade rhythm did not change significantly [13]. In another small study, six months of rehabilitation after repair did not fully restore normal shoulder blade movement [14].
• It matters to the result. In 48 patients followed for a year of rehabilitation after repair, substitution by the shoulder blade decreased but stayed greater than on the other side. Those in whom the physiotherapist saw substitution had worse scores, less movement and less strength at every time point [15]. In 110 patients 6 to 18 months after repair, dyskinesis went with poorer function, and scapular muscle endurance predicted the result [16].

Can targeted rehabilitation change it? In 60 patients with dyskinesis after repair, adding strengthening of the specific weak shoulder blade muscles (identified on EMG) gave a Constant score of 87.2 against 83.9, and forward elevation of 137° against 128°, at 16 weeks. That gap is modest, and the study was not randomised [17]. A 2026 meta-analysis found that scapular-targeted rehabilitation reduced pain and improved function across rotator cuff care, but the post-operative evidence was too thin to pool [18]. More broadly, exercise reliably helps pain and function in impingement [19], but the evidence that it changes the movement of the shoulder blade itself is conflicting [20].

An animal study raised the possibility that an abnormally moving shoulder blade could impair how a repaired tendon heals: in rats, cutting the nerves that control the shoulder blade before a supraspinatus repair gave weaker and less organised repairs [21]. This has not been shown in people.

After other shoulder operations

• Latarjet. Dyskinesis was seen in 5 of 20 patients after a Latarjet and none of 20 after a bone-graft stabilisation that leaves the coracoid alone. Those with dyskinesis had lower scores [22]. A later series found it in 25% after the standard operation and in none of 20 patients after the pectoralis minor was repaired back to the coracoid. 4 of the 5 cases settled with six months of specific rehabilitation [23].
• Shoulder replacement. After reverse replacement, the shoulder blade does more of the work of lifting the arm than in a normal shoulder (a meta-analysis of 464 patients) [24]. In 85 anatomic and reverse replacements, more shoulder blade contribution after surgery went with more pain and worse function [25].
• Collarbone and AC joint. Dyskinesis was found in 9 of 24 people after a displaced collarbone fracture, and they had more pain and worse scores. It was seen in 1 of 12 treated with surgery and 8 of 12 treated without [26]. After surgery for acute AC joint dislocation it was seen in 4 of 34 [27].

Trapezius pain and the shrug

There is very little research on aching in the trapezius or the side of the neck after shoulder surgery. No study has measured how often it happens. The closest evidence is the "shrug sign", where the whole shoulder girdle lifts as the arm is raised. In 982 consecutive patients examined before surgery, it was present in 51%, most often in frozen shoulder (95%). It went with stiffness, weakness and night pain, and it was not specific for a cuff tear [28]. That fits a simple explanation for trapezius ache while a shoulder recovers: the shoulder blade elevators work harder to lift an arm that is stiff or weak, as shown in painful cuff tears [9]. The sling strap may add to it. These explanations are reasonable, but they have not been tested. Pain that spreads down the arm with numbness, tingling or weakness points to the neck or a nerve instead and should be checked.