3D printed navigation template-guided minimally invasive percutaneous plate osteosynthesis for distal femoral fracture: A retrospective cohort study.

OBJECTIVE: To evaluate functional and radiological outcomes in distal femoral fracture patients (distal femoral shaft fractures or metaphyseal fractures) receiving indirect reduction and internal fixation with the minimally invasive percutaneous plate osteosynthesis (MIPPO) assisted by 3D printing navigation templates.

METHODS: This retrospective study included all adult (≥18 years) patients who underwent MIPPO for distal femoral fracture (AO32/33) at PLA 960 Hospital, Jinan, China between January 1, 2013 and December 31, 2016. 3D printed navigation templates were used to assist surgery. Functional assessment was performed using the Knee Society Score (KSS) and the Functional Knee Society Score (FKSS). Postoperative deformity was assessed with 3D-CT reconstruction using contralateral (non-fracture) side as the reference.

RESULTS: A total of 54 patients underwent MIPPO for distal femoral fracture during the review period (34 and 20 for conventional and template-guided MIPPO, respectively). At 10-14 months, the KSS score was 160.6 ± 18.1 and 167.5 ± 17.2 in the conventional and template-guided MIPPO groups, respectively (p = 0.18). The FKSS was 77.6 ± 9.4 in the conventional MIPPO group vs. 81.0 ± 8.5 in the template-guided MIPPO group (p = 0.15). Femoral length difference was smaller in template-guided MIPPO group (3.31 ± 1.53 vs. 9.50 ± 4.49 mm in the control; p < 0.01). Template-guided MIPPO group also had smaller anatomic lateral distal femoral angle (aLDFA) difference (1.57° ± 0.72° vs. 3.89° ± 1.72° in the control; p < 0.01), anatomic posterior distal femoral angle (aPDFA) difference (1.95° ± 0.78° vs. 5.04° ± 1.78°; p < 0.01), and anteversion angle difference (2.52° ± 1.00° vs. 8.23° ± 4.07°; p < 0.01). The rate of length discrepancy (>20 mm), coronal angulation deformity (aLDFA difference >5°), sagittal angulation deformity (aPDFA difference >10°), and rotational malalignment (anteversion angle >10°) was 5.9%, 20.5%, 2.9%, and 32.4% in the control group. No patients in the template-guided MIPPO group had deformity of any type.

CONCLUSIONS: MIPPO assisted by 3D printing navigation templates could practically improve surgical accuracy and eliminate postoperative rotational deformity in patients with distal femoral fractures.