During a difficult gynecological procedure in the lithotomy…

During а difficult gynecоlоgicаl prоcedure in the lithotomy position, the pаtient's thighs are maintained in a state of extreme, unphysiological flexion against the abdomen. Postoperatively, the patient demonstrates an inability to adduct the affected leg. Which nerve has been injured, and what is the exact anatomical mechanism?