It may be OA knee or Meniscal-Ligament degeneration. Locking may be due to meniscus or Ligament injury due to degeneration. Need Xrays and further evaluation.

This treatment is being on bases of the information provided.  However I would like to examine & investigate the patient   in detail. -Control  Hypertension, Diabetes or  metabolic disorder, if there is any.  -Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. -(You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Keep a pillow under the knee. --. Avoid painful acts & activities. -- .Do mild exercises for the lower limbs. --.(Take help of physiotherapist or you can visit my you tube channel Dr NC Gupta.)   & see  me and my yoga; & yoga simplified. Kindly subscribe to the channel to get notifications for further new information of your interest.  --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment visit nearest hospital. --Wish you a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.   Dr N C Gupta MS (ortho) DMC 3624  

Get standing knee xray

Might be Osteoarthritis Knee Do X-ray scan Both knee ap/Lat