Objective To investigate the efficacy of anti-infective reconstituted bone xenograft (ARBX) combined with external fixation in the treatment of adult infective nonunion of humeral shaft.Methods A retrospective case series study was conducted to analyze the clinical data of 18 patients with infected nonunion of humeral shaft admitted to Xijing Hospital of Air Force Military Medical University from January 2014 to December 2016.There were 10 males and eight females,aged 19-62 years [(36.9 ± 11.8)years].According to Umiarov classification of infective nonunion,there were 11 patients with type Ⅲ and seven with type Ⅳ.All patients were treated with anti-infective reconstituted bone xenograft (ARBX) combined with external fixation.The number of operations,bone healing time,bone healing rate,infection control rate,postoperative weight bearing time,the time of external fixation removal,postoperative complications,erythrocyte sedimentation rate (ESR),and C-reactive protein (CRP) before and after operation were recorded.Fracture healing and functional recovery were evaluated using the Johner-Wruch lower limb function score.Results The patients were followed up for 12-30 months [(21.3 ±5.6)months].The operation was performed for (1.4 ±0.9) times,with time of bone healing for (16.6 ± 5.8)months,bone healing rate of 83％ (15/18),and infection control rate of 94％ (17/18).The postoperative weight bearing time in 15 patients who obtained bone healing was (3.3 ± 1.5)months after operation,and the external fixation removal time was (18.5 ± 4.2) months after operation.There were three patients with nonunion after operation including one with infection recurrence.Five patients were found with nail tract infection.ESR and CRP at postoperative 3 months [(13.1 ± 8.4)mm/h and (5.6 ± 4.6)mg/L] were significantly lower than those before operation [(47.3 ± 19.2)mm/h and (23.4 ± 7.4) mg/L] (P ＜ 0.05).According to Johner-Wruch lower limb function scores,the results were excellent in nine patients,good in four,fair in one,and poor in four,with excellent and good rate of 72％.Conclusion ARBX combined with External fixation can effectively treat infective nonunion of humeral shaft,improve bone healing rate,and promote function recovery.