Background: Management of chronic collateral ligament injury of the Metacarpophalangeal (MCP) joint, either its Ulnar Collateral Ligament (UCL) or Radial Collateral Ligament (RCL), is challenging. 
Objectives: In this study, we report the outcome of ligament reconstruction procedure in the treatment of such injuries. 
Methods: In a retrospective study, the outcomes of static reconstruction surgery of the symptomatic chronic collateral ligament injury of the thumb MCP joint (five RCL and three UCL) were evaluated. We used palmaris longus tendon in four surgeries and flexor carpi radialis tendon in the remaining. The outcome measures included the thumb range of motion, the disabilities of the arm, shoulder, and hand (QuickDASH) questionnaire, pinch and grip strength, visual analog scale, and Kapandji opposition score.
Results: Eight patients (6 males and 2 females) with the mean±SD age of 32±7.1 years were included in this study. The Mean±SD duration from the injury to surgery was 66.7±99.5 weeks. The Mean±SD follow-up of the patients was 4.88±1.35 years. The mean pinch and grip strength of the involved hand averaged 98.9% and 100% of the other hand, respectively. Postoperative pain was only noticed in two patients. The Mean±SD postoperative Kapandji opposition score was 9.4±0.7 (range: 8-10). The Mean±SD QuickDASH score was 12.9±1.9 (range: 11-17). The thumb range of motion was similar to the contralateral hand in all but one patient. All the operated joints were stable. A case of mild degenerative joint disease was the only observed postoperative complication.
Conclusion: Static reconstruction of chronic collateral ligament injury of the thumb MCP joint provides acceptable results, regardless of the time interval between the injury and surgery.