A knee scab with pus inside should be seen by a doctor to clean out the necrotic tissue and foreign material. Knee scabs with pus inside need to be treated as infected wounds, which can usually present with significant redness, swelling, and pain. In this case, consider first cleaning the wound with iodophor, hydrogen peroxide, saline and other preparations, then incise the scabbed wound and clean the purulent secretions and necrotic tissue. Then use sterile gauze to dress the wound and change the dressing regularly. If the wound infection is more serious, consider using antibiotic drugs for anti-infection treatment, such as penicillin, ceftriaxone, etc.; and consider whether tetanus vaccine is needed according to the depth of contamination in the wound, etc. To summarize, it is recommended that patients consult a doctor in a timely manner and follow the doctor’s instructions to standardize the treatment, do not blindly treat the wound on their own.