John Morellato1, Hakim Louati2, William Desloges3, Steven Papp1, J Whitcomb Pollock1. 1. Division of Orthopaedic Surgery, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada. 2. Orthopaedics Biomechanics Laboratory, The Ottawa Hospital, University of Ottawa, Ottawa, ON, Canada. 3. Hull Hospital, Gatineau, QC, Canada.
Abstract
OBJECTIVE: To examine the stability of plate (locking and non-) versus screw constructs in the fixation of these fractures. METHODS: An anteromedial coronoid facet fracture (OTA/AO type 21-B1, O'Driscoll type 2, subtype 3) was simulated in 24 synthetic ulna bones that were then assigned to 3 fracture fixation groups: non-locking plate, locking plate (LP), or screw fixation. Each construct was first cycled in tension (through a simulated medial collateral ligament) and then in compression. They were then loaded to failure (displacement >2 mm). Fracture fragment displacement was recorded with an optical tracking system. RESULTS: During tension testing, a mean maximum fragment displacement of 12 ± 13 and 14 ± 9 μm was seen in the locking and non-locking constructs, respectively. There was no difference in fragment motion between the plated constructs. All screw-only fixed constructs failed during the tension protocol. During compression testing, the mean maximum fragment displacement for the screw-only construct (64 ± 79 μm) was significantly greater than locking (9 ± 5 μm) and non-locking constructs (10 ± 9 μm). During load to failure testing, the maximum load to failure in the screw-only group (316 ± 83 N) was significantly lower than locking (650.4 ± 107 N) and non-locking constructs (550 ± 76 N). There was no difference in load to failure between the plated groups. CONCLUSION: Fixation of anteromedial coronoid fractures (type 2, subtype 3) is best achieved with a plating technique. Although LPs had greater stiffness, they did not offer any advantage over conventional non-LPs with respect to fracture fragment displacement in this study. CLINICAL RELEVANCE: Isolated screw fixation showed inferior stability when compared with plate constructs for these fractures. This could result in loss of fracture reduction leading to instability and posttraumatic arthrosis.
OBJECTIVE: To examine the stability of plate (locking and non-) versus screw constructs in the fixation of these fractures. METHODS: An anteromedial coronoid facet fracture (OTA/AO type 21-B1, O'Driscoll type 2, subtype 3) was simulated in 24 synthetic ulna bones that were then assigned to 3 fracture fixation groups: non-locking plate, locking plate (LP), or screw fixation. Each construct was first cycled in tension (through a simulated medial collateral ligament) and then in compression. They were then loaded to failure (displacement >2 mm). Fracture fragment displacement was recorded with an optical tracking system. RESULTS: During tension testing, a mean maximum fragment displacement of 12 ± 13 and 14 ± 9 μm was seen in the locking and non-locking constructs, respectively. There was no difference in fragment motion between the plated constructs. All screw-only fixed constructs failed during the tension protocol. During compression testing, the mean maximum fragment displacement for the screw-only construct (64 ± 79 μm) was significantly greater than locking (9 ± 5 μm) and non-locking constructs (10 ± 9 μm). During load to failure testing, the maximum load to failure in the screw-only group (316 ± 83 N) was significantly lower than locking (650.4 ± 107 N) and non-locking constructs (550 ± 76 N). There was no difference in load to failure between the plated groups. CONCLUSION: Fixation of anteromedial coronoid fractures (type 2, subtype 3) is best achieved with a plating technique. Although LPs had greater stiffness, they did not offer any advantage over conventional non-LPs with respect to fracture fragment displacement in this study. CLINICAL RELEVANCE: Isolated screw fixation showed inferior stability when compared with plate constructs for these fractures. This could result in loss of fracture reduction leading to instability and posttraumatic arthrosis.
Authors: Felipe Reinares; Nicolás Rojas; Andrés Calvo; Cristian Aravena; Juan Pablo Rieutord; Orlando Callejas; Roberto Montegu; Daniel Paccot Journal: JSES Int Date: 2021-02-09