ObjectiveTo summarize the relationship between shoulder instability and superior labrum anterior posterior (SLAP) lesion. MethodsThe characteristics of shoulder instability and SLAP lesion were analyzed, and the relationship between them in pathogenesis, clinical symptoms, and biomechanics was discussed by referring to relevant domestic and foreign literature. ResultsShoulder instability and SLAP lesion can occur both spontaneously and respectively. SLAP lesion destroys the superior labrum integrity and the long head of biceps tendon (LHBT) insertion, causing excessive humeral head displacement against glenoid, and leading to shoulder instability. While chronic repetitive or acute high-energy traumatic shoulder instability can in turn aggravate SLAP lesion, resulting in expansion and increased degree of the original lesion. Conclusion SLAP lesion destroys mechanisms of shoulder stability, while shoulder instability causes tears of the upper labrum and the LHBT, showing a connection between shoulder instability and SLAP lesion. However, the existing evidence can only demonstrate that shoulder instability and SLAP lesion induce and promote the development of each other, instead of a necessary and sufficient condition. Therefore, the specific causal relationship between the two remains unknown and needs to be further studied.
Objective To introduce a new theory of shoulder stability mechanism, rebalancing theory, and clinical application of this new theory for the shoulder instability and dysfunction of motion. Methods Through extensive review of the literature related to shoulder instability and dysfunction of the motion in recent years, combined with our clinical practice experience, the internal relation between passive stability mechanism and dynamic stability mechanism were summarized. Results Rebalancing theory of shoulder stability mechanism is addressed, namely, when the shoulder stability mechanism is destructive, the stability of the shoulder can be restored by the rebalance between dynamic stability mechanism and passive stability mechanism. When dynamic stability is out of balance, dynamic stability can be restored by rebalancing the different parts of dynamic stability mechanism or to strengthen the passive stability mechanism. When passive stability mechanism is out of balance, passive stability can be restored by rebalancing the soft tissue and bone of the shoulder. ConclusionRebalancing theory of shoulder stability mechanism could make a understanding the occurrence, development, and prognosis of shoulder instability and dysfunction from a comprehensive and dynamic view and guide the treatment effectively.