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Effects of Static Fixation and Dynamization after Interlocking Femoral Nailing Locked with an External Fixator: An Experimental Study in Dogs
Author(s) -
Durall Ignacio,
Falcón Carmelo,
DíazBertrana Ma Carmen,
Franch Jorge
Publication year - 2004
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.2004.04047.x
Subject(s) - medicine , interlocking , fixation (population genetics) , external fixator , femoral shaft , orthodontics , external fixation , femoral bone , surgery , femur , structural engineering , population , environmental health , engineering
Objective— To determine bone healing at 20 weeks, after either static fixation (SG) or after dynamization (DG) at 4 weeks in osteotomized canine femurs repaired with an interlocking nail (ILN) secured with a type I external skeletal fixator (ESF). Study Design— Experimental study. Animals— Ten adult beagle dogs. Methods— After mid‐diaphyseal femoral osteotomy, femurs in 10 dogs were repaired with an ILN secured with 4 (2 proximal, 2 distal) threaded custom pins (TP; 2.7‐mm‐diameter cortical screw with a 2‐mm shaft attached to the screw head) to which 2 parallel connecting bars were attached in a type I ESF configuration. In 5 dogs, dynamization was performed at 4 weeks by removing the connecting bars and 2 distal screws. Limb function, range of motion of the stifle joint (ROMSJ), radiographic evidence of bone healing, and complications were studied for 20 weeks. Results— Full limb function was achieved between 8 and 10 weeks in SG dogs, but a decreased ROMSJ was observed from 5 to 8 weeks. In DG dogs, full limb function occurred between 5 and 6 weeks except in 1 dog, and ROMSJ was considered normal in all dogs. Bone healing was not affected by dynamization. Average healing time for SG was 12.8 weeks, and for DG it was 13.6 weeks. Periosteal reaction at TP insertion points, osteolysis around the thread and head of TPs were observed in both groups. A windshield–wiper effect was observed at the tip of 1 ILN. Conclusion— ILN locked with a type I ESF can be used for fixation of mid‐shaft femoral fractures. Dynamization at 4 weeks did not affect bone healing but did prevent stifle ankylosis and promoted earlier limb function. Clinical Relevance— ILN locked with a type I ESF is seemingly a feasible method for repair of mid‐shaft femoral fractures and may decrease risk of nail failure.