ObjectiveTo investigate the effectiveness of the treatment under the guidance of “diamond concept” for femoral shaft fractures nonunion after intramedullary fixation.MethodsBetween January 2014 and December 2016, 21 cases of femoral shaft fractures nonunion after intramedullary fixation were treated with auxiliary plate fixation combined with autogenous iliac graft, and autologous bone marrow concentrate and platelet-rich plasma (PRP) gel under the guidance of the “diamond concept”. There were 13 males and 8 females, with an average age of 32.5 years (range, 17-48 years). All fractures were closed femoral shaft fractures. Four patients underwent internal fixation with plate and resulted in nonunion, then they were fixed with intramedullary nails, but did not heal either. The rest 17 patients were fixed with intramedullary nailing. Fracture nonunion classification: 4 cases of hypertrophic nonunion, 17 cases of atrophic nonunion; the length of bone defect was 1-3 mm; the duration from the last treatment to the current treatment was 10-23 months (mean, 14.3 months). The operation time, intraoperative blood loss, the time between operation and full loading, fracture healing time, and complications were recorded. The visual analogue scale (VAS) score and the imaging system of fracture healing of the extremities (RUST) of patients before operation and at last follow-up were recorded to evaluate the fracture healing; the function of the affected limb was evaluated according to the Schatzker-Lambert efficacy score standard at last follow-up.ResultsThe operation time was 105-160 minutes, with an average of 125.6 minutes; the intraoperative blood loss was 160-580 mL, with an average of 370.5 mL. All incisions healed by first intention, without vascular or nerve injury. All patients were followed up 22-46 months (mean, 26.5 months). All the fractures healed, with a fracture healing time of 3-7 months (mean, 4.8 months). During the follow-up, there was no infection, loosening, implant breakage, re-fracture, and other complications. The VAS score at last follow-up was 0.8±0.3, showing significant difference (t=7.235, P=0.000) when compared with preoperative score (5.2±3.7); the RUST score was 3.4±0.3, which was significantly higher than the preoperative score (1.5±0.7) (t=8.336, P=0.000). According to the Schatzker-Lambert effectiveness evaluation standard, the limb function was excellent in 16 cases, good in 4 cases, fair in 1 case, and the excellent and good rate was 95.42%.ConclusionNonunion after intramedullary fixation of femoral fracture treated with auxiliary plate combined with autogenous iliac graft, autogenous bone marrow concentration and PRP gel in accordance with the “diamond concept” can not only restore the stability of the fracture ends, but also improves the biological environment of the fracture site, and can improve the rate of fracture healing.