Thumb collateral ligament damages are athletic harms that cause the diminishment of grasping movement. Injuries to the radial collateral ligament (RCL) of the thumb are less frequent compared to those of the ulnar collateral ligament, which accounts for 10% to 40% of collateral ligament injuries in the thumb. Comprehensive rupture of the RCL can affect both fixed and active insecurity, which can direct to a foreseeable progression of aching disfigurement resulting in articular deterioration. The majority of authors concur that habitual RCL gashes should be surgically treated, styles of tendon graft reconstruction of the RCL that produce satisfactory results, furnishing stability to the radial aspect and aiming to prevent the onset of degenerative conditions in the metacarpophalangeal joint. Two cases of chronic RCL injuries of the thumb were treated with tendon graft reconstruction (palmaris longus) at the Department of Upper Limb Surgery, Military Hospital 175. At the 8-week follow-up, no sign of recurrence was found, and the patient had pain-free, acceptable functionality of the thumb. We evaluate the results based on five factors and achieve a score of up to 17 points. RCL injuries of the thumb treated by tendon graft reconstruction (palmaris longus) have initially good results, helping patients return to their regular activities with low chances of recurrences.