Table 1: Histology scoring criteria.

Periosteal callus
 Subjective size and qualityMinimal/mild = 3; prominent, well organized = 2; prominent disorganized = 1; incomplete union = 0
  Woven-lamellar bone percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% = 0
 Cartilage tissue percent0–25% = 3; 25–50% = 2; 50–75% or incomplete union = 1; 75–100% or fibrous nonunion = 0
 Fibrovascular tissue percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% or fibrous nonunion = 0
 Inflammation percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% = 0
Osteotomy site
 Bridging bony callus percent75–100% = 4; 50–75% = 3; 25–50% = 2; 10–25% = 1; 0–10 = 0
 Woven-lamellar bone percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% = 0
 Mineralized bone percent75–100% = 3; 50–75% = 2; 25–50% = 1; 0–25% = 0
 Fibrovascular tissue percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% or inflammatory exudate = 0
 Inflammation percent0–25% = 3; 25–50% = 2; 50–75% = 1; 75–100% = 0
Adjacent cortical bone
 Degree of osteolysisNone/minimal = 4; mild local expansion (remodeling) of osteonal canals = 3; <1 mm adjacent osteolysis = 2; 1–3 mm adjacent osteolysis = 1; >3 mm adjacent osteolysis = 0
 Extent of bone necrosisEmpty lacunae and/or necrotic osteons: <2.5 mm = 4; 2.5–5 mm = 3; 6 mm–10 mm = 2; 11–20 mm = 1; >20 mm = 0
 Extent of inflammationNone/minimal = 4; mild local ostonal canals inflammation = 3; inflammation >1 mm distance = 2; 1–3 mm distance = 1; >3 mm distance = 0
 Presence of sequestra, for example, necrotic fragments of boneNone = 8; 1–3 small <2 mm = 4; >3 or single large >2 mm = 2; single to multiple large >5 mm = 0
Presence of bacteriaNone = 8; rare small colonies = 4; multifocal colonies (<25 µm) = 2; multifocal large colonies (>50 µm) = 0