Consolidation of the Anteromedial Aspect of the Tibia is Inferior to The Other Areas in the Reconstruction of Critical-Sized Bone Defect of the Tibial Shaft using the Induced Membrane Technique: An Analysis of 111 Serial Computed Tomography of 37 patients.

Objectives: To compare the consolidation quality between the anteromedial aspect of regenerated bone (AMRB) and other areas of regenerated bone (TORB) following the induced membrane technique (IMT) for managing critical-sized tibial shaft bone defects, and determine the factors affecting consolidation quality in the AMRB.

Methods: Design: Retrospective comparative study.

Setting: Academic Level I trauma center.

Patients Selection Criteria: Included were patients who underwent IMT with only an intramedullary nail for tibial shaft segmental defects and serial computed tomography immediately, 6 months, and 1 year postoperatively.Outcome Measures and Comparisons: Comparison were made of regenerative bone volume, density, and corticalization between AMRB and TORB.

Results: This study enrolled 37 patients with a mean age of 47.7 years (range 20-79). Twenty-eight (75.7%) patients were male. Postoperatively, the AMRB exhibited significantly more negative volumetric change than TORB at 0-1 year (-20.01% ± 25.59% vs. -13.32% ± 22.48%, p = 0.028), less positive density change 0-6 months (+197.84 ± 107.95 vs. +290.14 ± 131.74 HU, p < 0.001) and 0-1 year (+377.51 ± 150.71 HU vs. +455.48 ± 135.04 HU, p < 0.001), and lower corticalization rate in 1 year (49.77% ± 29.42% vs. 82.27 ± 19.73%, p < 0.001). Significant factors included fracture-related infection (FRI) (p = 0.047 and p = 0.048 at 0-6 months and 0-1 year, respectively) and longer defect length (p = 0.032 and p = 0.020) for the negative volumetric AMRB changes; older age (p = 0.004 and p = 0.016) for the AMRB negative density changes; higher percentage of mixed recombinant human bone morphogenetic protein-2 in graft material (p = 0.013 in 0-6 months) for the AMRB positive density change; FRI (p = 0.024) for the inferior corticalization rate of the AMRB; FRI (p = 0.026 in 0-1 year), longer defect length (p = 0.017 in 0-6 months), and higher mixed demineralized bone matrix (DBM) percentage (p = 0.010 in 0-1 year) for the difference in density change between the AMRB and TORB; higher mixed DBM percentage (p = 0.023) for the difference between the AMRB and TORB in corticalization rates.

Conclusions: The tibial shaft's anteromedial aspects demonstrated significantly inferior consolidation after induced membrane technique, especially in terms of volume at 6 months, density at 6 months and 1 year, and corticalization at 1 year postoperatively.

Level Of Evidence: Therapeutic Level III.