Hip microinstability diagnosis and management: a systematic review

PURPOSE: The purpose of this systematic review is to present the most common causes, diagnostic features, treatment options and outcomes of patients with hip micro-instability. METHODS: Three online databases (MEDLINE, Embase, and PubMed) were searched from database inception March 2022, for literature addressing the diagnosis and management of patients with hip micro-instability. Given the lack of consistent reporting of patient outcomes across studies, the results are presented in a descriptive summary fashion. RESULTS: Overall, there were a total of 9 studies including 189 patients (193 hips) included in this review of which 89% were female. All studies were level IV evidence with a mean MINORS score of 12 (range: 10-13). The most commonly used features for diagnosis of micro-instability on history were anterior pain in 146 (78%) patients and a subjective feeling of instability with gait in 143 (81%) patients, while the most common feature on physical examination was the presence of anterior apprehension with combined hip extension and external rotation in 123 (65%) patients. The most common causes of micro-instability were iatrogenic instability secondary to either capsular insufficiency or cam over-resection in 76 (62%) patients and soft tissue laxity in 38 (31%) patients. CONCLUSION: The most common symptom of micro-instability on history was anterior hip pain and on physical exam was pain with hip extension and external rotation. There are many treatment options and when managed appropriately based on the precise cause of micro-instability, patients may demonstrate improved outcomes. LEVEL OF EVIDENCE: IV.