The most common reasons for not straightening fingers in basketball are trauma, tenosynovitis, rheumatoid arthritis, etc. The most common reasons for not straightening fingers in basketball are trauma, tenosynovitis and rheumatoid arthritis. 1. Trauma: If the patient’s fingers are injured by undue force in the process of playing basketball, it is easy to cause finger pain and inextensibility, which is usually accompanied by finger movement disorders. 2. Tenosynovitis: If the patient has tenosynovitis, the fatigue of the finger tendons will easily trigger the onset of tenosynovitis, which will cause joint pain and limitation of activities, manifested by the inability to straighten the fingers. 3. Rheumatoid arthritis: if the patient himself has rheumatoid arthritis, rheumatoid arthritis acute attack when playing basketball, it is easy to cause redness and swelling of the finger joints and not straight. Caused by playing basketball finger straight more reasons, but also may be related to fractures, tendon rupture and other reasons, if the symptoms continue to have no relief, it is recommended to go to the hospital in a timely manner to find out the cause of the disease, by the doctor targeted treatment.