OBJECTIVE: To study the effect of platelet-rich plasma (PRP) on repairing chronic wounds of lower limbs. METHODS: From May 2007 to November 2007, 47 patients suffering from chronic wounds of lower limbs were treated. There were 41 males and 6 females, aged from 15 to 68 years (43.2 years on average). The disease was caused by tibiofibular fracture in 20 cases, calcaneus fracture in 4 cases, metatarsal fracture in 1 case, multiple open fracture of lower limbs in 3 cases, tibia osteomyelitis in 10 cases, femur osteomyelitis in 1 case, soft tissue injury of ankle in 4 cases, infection after amputation in 2 cases, infection after foot orthomorphia in 1 case, and infection after calcaneus tendon neoplasia in 1 case. Their chronic wounds did not healed after 2 to 4 months of therapy. Among them, chronic wounds complicated with fracture nonunion in 23 cases and positive bacterial culture result in 38 cases. Debridement and autogenous PRP gel injection were applied every 2 months and for twice. RESULTS: The patients were followed up for 4 months after the first PRP injection. Two months after the first PRP injection, chronic wounds contracted significantly in 34 patients with purulence and necrosis tissue cleaned up, circulation of soft tissue improved and exposed bone or muscle tissue covered by neurogenetic granulation. No patient was completely cured. Two months after the second PRP injection, the average coverage rate was 79.3% +/- 18.0%, the total cure rate was 29.8%. The volume of the chronic wounds decreased by (9.3 +/- 4.9) mL after PRP therapy (2.5 +/- 2.7) mL when compared with (11.8 +/- 5.6) mL of before therapy, showing significant difference (P < 0.05). X-ray photograph showed that among the 23 cases of fracture nonunion, fracture healed completely in 9 cases; bony callus formation increased obviously in 12 cases; no significant change was observed in 2 cases. No aggravated sign of osteomyelitis was notified. Positive results of bacterial culture reduced to 15 cases. CONCLUSION: PRP efficiently enhances the recovery of soft tissue defect and speeds up the chronic wounds healing of lower limbs.