Biomechanical Comparison of Dual Interlocking Single Loop and Double Loop Tension Band Techniques to the Classic AO Tension Band Technique for Repair of Olecranon Osteotomies in Dogs

Abstract

To compare olecranon fragment stability between the classic tension band wire (TBW) technique with the wire placed either in contact with (Arbeitsgemeinschaft für Osteosynthesefragen [AO]), or not in contact with, a Kirschner (K)-wire (AOW) to 2 novel wire patterns: a dual interlocking single loop (DISL) and a double loop (DL). Ex vivo mechanical evaluation on cadaveric bones. Canine ulnae (n=40) with olecranon osteotomies repaired with 2 K-wires and 1 of 4 TBW constructs. Single load to failure applied through the triceps tendon. Displacement was measured from images captured from digital video. Techniques were compared based on the load resisted when the olecranon fragment was displaced 0.5, 1, and 2 mm. At 0.5 mm of displacement, the DISL construct resisted more load than the AOW construct (505 versus 350 N; P=.05). AO and DL constructs resisted an intermediate load (345 and 330 N, respectively). There was no significant difference between groups at 1 mm of displacement. At 2 mm of displacement, DL (785 N) resisted more load than AO (522 N, P=.01) and AOW (492 N, P=.03) groups. DISL constructs provided similar stability to classic TBW constructs whereas DL constructs were more stable at higher loads. The DL construct is easy to perform, less bulky, and provides comparable fragment stability to standard TBW techniques at functional loads. Surgical method is important for optimal performance of all TBW constructs.