Mechanical comparison of different plate-and-screw configurations for repairing forearm diaphysis fractures: a systematic review.

PURPOSE: This is the first systematic review of all studies that adjusted plate and/or screw variables to determine the most mechanically stable implant configuration for forearm fracture repair. METHODS: PubMed and Scopus archives were searched using the phrase “biomechanics” AND “fracture” AND “plate” AND (“forearm” OR “radius” OR “ulna”). Eligibility criteria were applied: (i) studies that mechanically analyzed implant performance by modulating plate and/or screw variables, such as plate geometry, plate material, screw number, etc.; (ii) forearm diaphysis “shaft” fractures of the radius and/or ulna; (iii) studies published at any time; (iv) English language studies. RESULTS: There were 34 eligible papers. There was greater mechanical stability for these configurations: (i) plates used alone or double-stacked; (ii) plates that were longer, wider, thicker, straight or curved at the bottom, non-ribbed at the bottom, and/or non-grooved at the sides; (iii) plates made of material with higher elastic modulus; (iv) plates that were locking; (v) plates not elevated above bone; (vi) plates affixed to the anterior side of bone; (vii) screws that were longer, thicker, and/or numerous. There was a range of numerical outcomes: (i) interfragmentary motion; (ii) peak stress in cortical bone or plates; (iii) cortical bone stress under the plate to assess bone “stress shielding”; (iv) fatigue life; (v) stiffness; (vi) strength. General observations, implant variables, bone factors, applied loads, outcome metrics, and clinical recommendations are discussed. CONCLUSIONS: Mechanical analysis can help design, analyze, or use forearm fracture plate-and-screw implants so they providegreater mechanical stability.