Evidence for arthrogenic inhibition of the gluteus medius after anterior cruciate ligament injury: A systematic review.

PURPOSE: Arthrogenic muscle inhibition (AMI) is a reflex inhibition following joint injury or surgery affecting periarticular muscles. While AMI has been extensively studied in the quadriceps after anterior cruciate ligament (ACL) injury, its potential impact on the gluteus medius remains unclear. Given the muscle's critical role in pelvic and lower limb control, clarifying this relationship may have important implications for rehabilitation strategies after ACL injury. The purpose of this study is to search for a relation between ACL injuries and arthrogenic inhibition of the Gluteus medius in the ipsilateral hip. METHODS: A structured review of 12 peer-reviewed studies was conducted, assessing Gluteus medius or hip muscle function after ACL injury or reconstruction. Eligible studies evaluated muscle activation, strength and neuromuscular adaptations using electromyography (EMG), dynamometry or biomechanical motion analysis. Data were summarised to evaluate the presence and clinical significance of AMI affecting the gluteus medius. RESULTS: Among the included studies, two reported clear signs of gluteus medius inhibition after ACL injury or reconstruction. Several demonstrated reduced activation and weakness of the gluteus medius, suggesting a potential inhibitory mechanism. Specifically, EMG-based findings in two studies supported altered neuromuscular recruitment patterns, while three others identified movement strategies with compensation or abductor weakness. However, some other studies reported no significant deficits, highlighting interstudy variability due to differing methods, population characteristics or time since injury. Despite these differences, a general trend towards proximal neuromuscular adaptation appears relevant. CONCLUSION: There is emerging evidence that suggests the presence of gluteus medius dysfunction suggestive of AMI following ACL injury in certain individuals. While not universally observed, this inhibition may impair dynamic hip stability and functional recovery. Future research should explore whether targeted hip muscle training can reduce persistent neuromuscular deficits after ACL injury. LEVEL OF EVIDENCE: Level III.