Edward has a chronic pain in his leg. The defect would be him not being able to walk right. It all happened during the phenomenon at the track meet, which he deeply remorses. He was running so savagely to the point of pulling a muscle. Running was so sentimental to him. All of his acquaintances were involved with track, it was more or less his morality. The doctors implication was to stay off his leg for a while. He was furious about it but kept his sanity.