Inclusion and exclusion criteria
Inclusion criteria: (1) Patients older than 18 years; (2) Patients with large segmental bone defects after trauma; (3) Patients with complete medical records; (4) Patients with bone defects longer than 8 cm; (5) Patients were treated by bone transport technique at the initial stage.
Exclusion criteria: (1) Patients younger than 18 years; (2) Patients with bone defects less than 8 cm; (3) Patients with non traumatic bone defects; (4) Patients with severe medical diseases unable to tolerate a surgery or anesthesia; (5) Passive removal of the transport frame due to poor osteogenesis or intolerance; (6) Patients with incomplete medical records.
General data
Eighty-four patients with large segmental bone defects after trauma treated in our institution from January 2014 to January 2017 were selected, and a total of 77 cases were completely followed. There were 54 males and 23 females, aged 19–68 years. Thirty-five patients were treated by bone transport combined with bone graft and internal fixation technique (Group A), and 42 by simple bone transport technique (Group B). This study was approved by the ethics committee of Xi’an Hong Hui hospital (IRB approval number: 202104018). All patients or their families have signed the informed consent before operation.
Preoperative treatment: Patients needed a general examination after admission. The affected limb was routinely examined by X-ray and CT, and the infection-related indexes such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were detected by blood sampling. For bone defects caused by an open fracture, damage control surgery should be performed first, including debridement and temporary fixation. For patients with chronic osteomyelitis, thorough debridement should also be performed, and sequestrum should be removed wholely. After infection was controlled and soft tissues healed, bone defects were repaired in time.
Surgical procedures
The annular external fixator (Naton, China) or single-arm transport frame (Naton, China) was placed. The limb length was maintained through traction. Meanwhile, the alignment and rotation deformity were corrected. Parallel to the articular surface, the distal and proximal ends of the long bone were fixed on the frame, respectively. The transport pins were inserted at the appropriate position to fix the transport segment. According to the surgical design, osteotomy was performed at the distal or proximal part of the long bone. The limb length and alignment were confirmed by an image intensifier. Then, the wounds were rinsed and sutured. The bone transport process began 1 week after operation.
For patients of Group A, when the bone defects were shortened to less than 5 cm, bone transport stopped. The transport frame was removed and the affected limb was fixed with a plaster or brace for 1 week. This would promote healing of the pin-tracts. After the pin-tracts healed, sequential bone graft and internal fixation started. With the residual bone defects as the center, a longitudinal incision was taken. The incision length was about 8–10 cm. It was cut layer by layer. The residual bone defects were exposed. Both ends of the bone defects were trimmed until there was good blood seepage on the bone surface. The scar tissues were removed, too. After thoroughly washing the wounds, a plate or intramedullary nail (Naton, China) shall be selected according to the preoperative design. The whole segment could be bridged by minimally invasive percutaneous placement of a plate. An intramedullary nail could also be placed. The distal and proximal ends of the intramedullary nail were locked, respectively. The residual bone defects were measured, the amount of autologous bones needed was roughly estimated, and the autologous iliac bones were taken and implanted into the residual bone defect site. Finally, a drainage tube was inserted and the incisions were closed. It was confirmed by an image intensifier that the transplanted bones were sufficient and the internal fixation position was good. A typical case was shown in Figs. 2 and 3.
For Group B, bone transport process continued until both ends of the bone defects were in contact. Bone ends were pressed properly to make the docking site heal initially. After the docking site firmly healed and the mineralization of the new callus finished, the transport frame could be removed. A typical case was shown in Fig. 4.
Postoperative treatment
After operation, according to the surgeon’s guidance, the passive and active functional exercises were properly carried out, and symptomatic treatments such as anti-inflammatory, detumescence and pain relief were given. During bone transport process, patients were required to recheck every 2 weeks. X-ray images were taken to evaluate the bone transport status and docking site healing. During the follow-up period, patients were guided to bear weight properly. Surgeons should correct their walking gait and teach them to avoid excessive or insufficient weight-bearing exercises.
Observation indexes
The follow-up time, time in external fixator, total cure time and number of operations for Group A and B were recorded. Patients were followed through outpatient review, telephone, wechat platform, etc. Limb functions were evaluated by Ennecking score [16], including pain, activity function, self feeling, brace use, walking ability and gait change. Each item was scored 0–5 points and the full score was 30 points. The cumulative score divided by 30 points was the percentage of normal limb function recovery. The anxiety status was evaluated by SAS score [17] which included no anxiety, mild anxiety, moderate anxiety and severe anxiety. Moreover, the total complication incidence was compared between Group A and B.
Statistical analysis
SPSS23.0 software was used to process data. Kolmogorov Smirnov was used to test whether the measurement data conformed to the normal distribution. The measurement data conforming to the normal distribution were expressed as mean ± standard deviation. Unpaired t-test was used for comparison between Group A and B. Counting data were analyzed by χ2 test, p < 0.05 was statistically significant.