There is no consensus for the appropriate surgical management of chronic ulnar collateral ligament (UCL) injuries of the thumb. A systematic review of Pubmed, MEDLINE, EMBASE and ePub Ahead of Print was performed in accordance with Preferred Reporting of Items in Systematic Review and Meta-analysis (PRISMA) guidelines and formal protocol registered with PROSPERO. Two authors collated data from 10 studies that met strict inclusion criteria, using various surgical techniques in 131 thumbs. Results were heterogenous and metanalysis of results not possible. These data were, therefore, qualitatively assessed and synthesised. Bias was assessed using the ROBINS-I tool. Direct repair, reconstruction with free tendon or bone-tissue-bone grafts and arthrodesis all demonstrated favourable outcomes with Patient Reported Outcome Measures. Direct repair can be safely performed more than two months following injury, with a positive mean Disabilities of the Arm, Shoulder and Hand (DASH) score of 13.5 despite evidence of radiographic osteoarthritis. Arthrodesis should be considered in heavy manual laborers or those at risk of osteoarthritis as it provides significant reduction in pain (Mean Visual Analogue Score of 1.2) when compared to other methods. Free tendon grafting has been criticised for failure rates and poor functional grip strength, however collated analysis of 97 patients found a single graft rupture and mean grip strength of 97% (of the contralateral thumb). Bone-tissue-bone grafting was the least effective method across all outcome measures. Studies included were at high risk of bias, however, it can be concluded that delayed direct repair can be performed safely, while arthrodesis may benefit certain patient subgroups. New findings suggest poor efficacy of bone-tissue-bone grafts, but that free tendon grafting with palmaris longus are in fact safe with good restoration of grip strength. The optimal graft and configuration are yet to be determined for reconstructive methods