Extra-articular coronal protrusion of volar locking plate and screw cutout in the treatment of distal radius fracture in coronal plane: Classification, clinical outcomes and how to prevent.

Background: Complications related to implant placement can occur during the surgical treatment of displaced distal radius fractures (DRF) with a volar locking plate(VLP). The literature has often focused on implant placement in the sagittal plane, whereas the coronal plane has been neglected. The purpose of this study was to evaluate the effect of VLP protrusions in the coronal plane in the surgical treatment of DRF.

Material and method: Between 2015 and 2022, 302 patients who underwent DRF surgery with VLP between 2015 and 2022 were included in the study. Patients were divided into group 1(anatomically located VLP) and group 2 (protruding VLP and/or screw cutout in the coronal plane), and statistically compared. Patients with radiocarpal intra-articular and sagittal plane protrusions, neurological problems, preoperative DRUJ injury, previous fracture or surgery in the ipsilateral upper extremity, malunion, or incomplete data were excluded. Patients with at least two years of follow-up were included in the study. The Fernandez classification was used for fracture classification. Group 2 patients were classified into subgroups according to the anatomical location of the protrusions: group A (metaphyseal radial styloid side), group B (ulnar metaphyseal side), and group C (diaphyseal side). Functional outcomes were statistically compared between subgroups in terms of the amount of protrusion (≥2 mm and <2 mm), brachioradialis (BR) and abductor pollicis longus (APL) tenosynovitis, distal radioulnar joint (DRUJ) irritation, and necessity for plate removal surgery. QuickDash and PRWE scores were used to assess functional outcomes.

Results: PRWE, QuickDash scores, and plate removal rates were higher in group 2 (p < 0.05).The demographic and radiological parameters were similar between the groups (P > 0.05).Within group 2, functional scores, BR and/or APL tendinitis, and plate removal were higher in group A cases with protrusion ≥2 mm and in group B cases with screw prominence in the DRUJ, whereas no difference was found between group A cases with protrusion <2 mm, group B caseswith pure protrusion of the VLP without screw, and all group C cases. All cases requiring plate removal were in group A ≥2 mm and had BR and/or APL tenosynovitis, and in group B with screws penetrating the DRUJ. Functional scores improved significantly after plate removal in all patients requiring plate removal (p < 0.05).

Conclusion: ≥2 mm protrusion in group A and group B cases with screw cutout to the DRUJ, the results are unsatisfactory and implant removal is required in these cases. If the screw hole was left empty in the protruded VLP in group B and in all group C cases, clinical outcomes were not significantly affected.