Healing process after rigid plate fixation of humeral shaft fractures revisited

Objective: The purpose of this study was to describe the radiological healing process after open reduction and internal fixation (ORIF) of humeral shaft fractures with plate. Materials and methods: We reviewed the data of 53 consecutive patients who had undergone rigid plate fixation of OTA 12 A or B humeral shaft fracture. The mean age of the patients at the time of surgery was 39.4 (range 16-82). Quality of reduction and healing process was analysed on radiographs. Clinical symptom and disabilities of the arm, shoulder and hand (DASH) scores were recorded at follow-up visits. Results: There were 28 compression and 25 neutralization platings. The mean gap size on the postoperative radiograph was 1.4 (range 0.1-6.1). 50 cases (94.3 %) healed, while three cases ended up with non-union. 28 (52.8 %) cases showed primary healing and 22 cases (41.5 %) showed secondary healing with callus bridging. Among the cases with secondary healing, callus formation with resorption was identified in 13 cases. The type of fracture, mode of compression and size of gap on radiographs after rigid plate fixation were found to be statistically significant factors for healing type (p = 0.026, 0.002, and <0.001, respectively). Three cases with non-union showed no improvement in DASH scores. Conclusion: Both primary and secondary healing processes were observed after rigid plate fixation of OTA 12 A or B humeral shaft fractures. Our study revealed that size of gap, mode of compression, type of fracture could affect the type of healing, and that periosteal callus formation can occur after rigid plate fixation.