B

Small, controlled inter-fragmentary motion stimulates secondary (indirect) bone healing, leading to a larger external callus, whereas rigid compression plating or strict immobilization favor primary healing with little callus. Animal and biomechanical studies show that limited movement increases periosteal callus size compared with rigid fixation [Claes, 2000, PMID 11043114; Yamaji, 2001, PMID 11793181; Goodship, 1998, PMID 9917631].