Anterior cruciate ligament (ACL) injury is a common sport injury in both professional and recreational athletes. Furthermore, persistent quadriceps weakness and wasting are frequently observed after anterior cruciate ligament reconstruction (ACLR). Several studies have demonstrated that muscular rehabilitation to normal strength is difficult, protracted, and often not achieved due to the inability to fully activate the quadriceps voluntarily. Pain and disuse are often blamed for the inhibition of muscle activation following joint injury. However, arthrogenic muscle inhibition (AMI) is often overlooked and not addressed. Thus, the magnitude of strength restoration of the quadriceps is frequently restricted despite solid rehabilitation protocols. As AMI is a reflex inhibition of musculature involving the neurotransmitter γ-aminobutyrate (GABA), Gabapentin may have a potential role in modulating AMI, therefore limiting muscle weakness after ACLR.

Inclusion Criteria:

1. Age 18-50
2. Unilateral isolated ACL tear for primary ACLR confirmed clinically and radiologically
3. No concomitant ligamentous, meniscal or chondral injuries.

Exclusion Criteria:

1. Concomitant multiple ligament injuries including posterior cruciate ligament, medial collateral ligament ligament, or lateral collateral ligament
2. Concomitant meniscal injuries
3. Concomitant chondral injuries
4. preoperative radiographic signs of arthritis
5. Revision ACL surgery
6. Contralateral knee with
7. Medical co-morbidities including Diabetes Mellitus, chronic renal failure
8. Documented hypersensitivity to Gabapentin
9. History of epilepsy
10. History of depression
11. Non-compliance to rehabilitation protocol.