Editorial Commentary: Hip Joint Laxity, Microinstability, or Instability Require Precise Definition: No Matter What...

Hip instability has gained recognition as an important cause of hip pathology. Causes include incongruency of the articular surfaces due to dysplasia and/or impingement, joint capsule pathology, labral pathology, ligamentum teres tears, ligamentous laxity, muscular imbalance, and tendon tears. Lacking clearly defined symptoms and tests has hindered identification and treatment of this condition. Furthermore, the relevant literature uses different terms such as hyperlaxity and microinstability to describe this patient population, conveying different messages. However, the different terms convey different messages. Joint hyperlaxity or hypermobility has sometimes been used in reference to the hip; however, these usually refer to a genetic ligamentous and capsular condition affecting collagen structure, such as in Ehlers Danlos Syndrome. More common, and often interchangeable, terms are instability and microinstability. As the authors state in the present study, 'instability' has the advantage of conveying the significant impact the condition has on a patient's life. On the other hand, 'microinstability' may more accurately reflect the vague clinical presentation that we often encounter in the average hip patient with instability. Most patients do not complain of symptoms commonly seen in other joints with "instability," such as giving way, subluxation, and recurrent dislocations. In the hip, the symptoms are generally less tangible, and hence, the term "microinstability" may be more appropriate.