Background To quantitatively evaluate bone mineralization following bifocal (BF), trifocal (TF), tetrafocal (TBT), and pentafocal (PBT) bone transport using the pixel value ratio (PVR), and to compare the clinical efficacy of different bone transport strategies in treating large segmental defects (≥ 6 cm) of the lower limb.Methods A retrospective study was conducted on 122 patients with large lower-limb bone defects treated with bone transport at the First Affiliated Hospital of Xinjiang Medical University between 2017 and 2023. Patients were divided into four groups: BF (n = 50), TF (n = 37), TBT (n = 20), and PBT (n = 15). Standardized digital radiographs were obtained at 2, 4, 6, 8, 10, and 12 months postoperatively to measure PVR. Demographic and clinical data were collected, including age, sex, lengthening distance, healing time, healing index (HI), external fixation time, and external fixation index (EFI). Limb function recovery was assessed using the ASAMI scoring system.Results No significant differences were observed among the four groups regarding age, sex, BMI, lengthening distance, or high-risk factors (smoking, alcohol consumption, obesity, hypertension, diabetes) ( P > 0.05). The PVR values in the TF, TBT, and PBT groups were significantly higher than those in the BF group at all time points (P < 0.001). Significant differences in HI and EFI were found among groups (P < 0.001), and both were negatively correlated with PVR. No statistically significant differences were found in the distribution of ASAMI bone or functional outcomes among the four groups (P > 0.05).Conclusions Multi-level bone transport enhances early mineralization efficiency and shortens external fixation duration without compromising final clinical outcomes. PVR serves as a reliable quantitative indicator for monitoring regenerate maturation and may assist in clinical decision-making regarding dynamization and frame removal.