Objective To explore the clinical outcomes of Ligament reconstruction tendon interposition (LRTI) arthro-plasty for first carpometacarpal joint osteoarthritis. Methods From January 2008 to January 2011, 19 patients (21 thumbs) had surgery for thumb carpometacarpal arthritis using ligament reconstruction tendon interposition arthroplasty with flexor carpi radia-lis (FCR). There were 1 male and 18 were females with an average age of 60 years (range, 52-75 years);8 thumbs were on the left side and 13 thumbs on the right side. According to Eaton-Glickel classification, 1 thumb belonged to stageⅡ, 14 thumbs to stageⅢ, and 6 thumbs to stageⅣ. Pain level, grip strength, tip pinch strength, range of motion, and radiographic measurement were re-corded. According to the first metacarpal subsidence, the cases were classified in mild, moderate, and severe groups. Clinical out-comes of different group were evaluated and compared. Results All patients were followed up for 9-28 months with an average of 13.9 months. Comparision with the preoperative X-rays showed the first metacarpal had subsided 54.8% of the arthroplasty space after surgery. Grip strength improved from 18.6±10.1 kg to 20.5±11.9 kg, and tip pinch strength increased from 4.4±2.1 kg to 4.5 ± 1.9 kg after the surgery. Radial abduction increased from 55.7° ± 8.2° to 60.6° ± 7.2° and palmar abduction improved from 56.7° ± 8.5° to 63.5° ± 8.2° after the procedure. Patient pain levels (visual analogue scale, VAS) were significantly reduced, from 6.6 ± 1.4 to 0.5 ± 0.7. There was no difference of grip strength, tip pinch strength, thumbs range of motion, and VAS after LRTI in mild, moderate and severe groups. Conclusion LRTI resulted in excellent relief of pain and increase in range of motion. Howev-er, LRTI cannot sustain the arthroplasty space. Compared with the preoperative X-ray, the first metacarpal subsided more than 50%. Subsidence of the first metacarpal doesn't affect the pain relief, range of motion and strength improvement.