Abstract
BackgroundPlate protrusion is a risk factor for flexor pollicis longus (FPL) rupture following volar locking plate (VLP) surgery. However, plate prominence on follow-up radiographs is common. We hypothesised that a VLP that does not touch the FPL tendon can appear as a plate prominence projected over the volar ridge on lateral radiographs.Materials and methodsWe studied six current designs of widely used plates in formalin-fixed cadavers. Each plate was placed in six cadavers. We analysed 36 different plate–cadaver combinations. The main aim of plate fixation was to position the plate in the most distal position without FPL tendon contact. Radiographs were obtained using fluoroscopy. We evaluated plate prominence from the volar ridge according to the Soong grading system.ResultsSoong grades 0 (plate did not extend beyond volar ridge), 1 (plate protruded beyond volar ridge) and 2 (plate directly on or located beyond the volar ridge) were observed in 23 (63.9%), 9 (25.0%) and 4 (11.1%) cadavers, respectively. VariAx, DVR and VALCP showed grade 1 prominence, whereas Acu-Loc2, HYBRIX and MODE showed grade 2 prominence.ConclusionsImplant protrusion was observed in 36% of plate–cadaver combinations, even if the plate did not touch the FPL. Estimating the risk of FPL rupture using lateral radiographs alone is likely insufficient. Our findings can be applied to accurately identify the presence of implant prominence following VLP surgery.
Highlights
The volar locking plate (VLP) system provides stable internal fixation to allow early rehabilitation and has been widely used for patients with distal radius fracture (DRF) [1]
Soong grades 0, 1 and 2 were observed in 23 (63.9%), 9 (25.0%) and 4 (11.1%) cadavers, respectively
Implant protrusion was observed in 36% of plate–cadaver combinations, even if the plate did not touch the flexor pollicis longus (FPL)
Summary
The volar locking plate (VLP) system provides stable internal fixation to allow early rehabilitation and has been widely used for patients with distal radius fracture (DRF) [1]. The watershed line was first described by Orbey and Touhami and defined as a transverse ridge bordering the pronator fossa distally [9]. This bony prominence is known as the distal limit of the VLP. Prominence of the plate after VLP surgery is commonly seen in follow-up radiographs, and not all protrusions cause FPL rupture [11, 12]. Plate protrusion is a risk factor for flexor pollicis longus (FPL) rupture following volar locking plate (VLP) surgery. We hypothesised that a VLP that does not touch the FPL tendon can appear as a plate prominence projected over the volar ridge on lateral radiographs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
