To propose a concept of irreducible tibial shaft fractures and to discuss their imaging characteristics and clinical significance.

A retrospective study was performed in 21 patients with tibial shaft fracture who had received intraoperative intramedullary nailing after limited open reduction at Department of Orthopaedics, The Second Affiliated Hospital to Anhui Medical University from November 2013 to June 2018. They were 14 males and 7 females, aged from 2l to 66 years (average, 34.9 years). There were 15 left and 6 right sides. Firstly, closed reduction was performed followed by traction, folding and rotation, but repeated attempts failed to achieve smooth reduction or insertion of guide wire. Next, local limited open reduction had to be performed for intramedullary nailing. The X-ray and CT images of the tibial fractures were collected to analyze their imaging characteristics. The imaging manifestations were characterized into 4 types: single-segment type with intact fibula, multiple-segment type, interlocking type where the distal and proximal ends interlock commonly seen in short spiral and short oblique fractures, and incarceration type where the fracture interspace is blocked by a bone fragment. The therapeutic efficacy was evaluated at the final follow-up by knee scores of The Hospital for Special Surgery (HSS) and Kofoed ankle scores.

Of the 21 patients, 2 were single-segment type, 4 multiple-segment type, 13 interlocking type and 2 incarceration type. They were followed up for 7 to 50 months (average, 22.7 months). The fractures united after 5 to 16 months (average, 7.3 months). Postoperative knee pain was observed in 3 cases and delayed fracture union in 2. Osteomyelitis, superficial wound infection, implant breakage or malunion occurred in none of the patients. The therapeutic efficacy evaluated at the final follow-up by HSS knee scores and Kofoed ankle scores revealed 15 excellent, 4 good and 2 fair cases, yielding an excellent to good rate of 90.5%.

The concept of irreducible tibial shaft fractures may lead to preoperative awareness on the part of the surgeons so that ineffective repeated reductions can be spared and the damage to the blood supply to the fracture ends and the operation time can be reduced.

Tibia fracture; Knee joints; Ankle joints; Imaging characteristics; Irreducible