Late Rupture of the Extensor Pollicis Longus Tendon: The Case against Attrition

Dorsal tangential view of the wrist to detect screw penetration to the dorsal cortex of the distal radius after volar fixed-angle plating

BACKGROUND

Extensor tendon irritation and attritional tendon ruptures are well-recognized complications, secondary to dorsal screw penetration following volar plating of the distal radius. Lateral and oblique views of the wrist have limited ability to detect such penetration, particularly at the ulnar side of the Lister's tubercle. In this report, we conducted an intraoperative fluoroscopic study to determine dorsal screw penetration in various positions of the wrist/forearm and compared the standard radiographic views (lateral, supination, and pronation views) with dorsal tangential view of the wrist.

MATERIALS AND METHOD

Standard lateral, oblique (in pronation and supination), and dorsal tangential views were obtained in 27 consecutive patients undergoing fixation a distal radius fractures using a volar plate. The number of penetrating screws in each dorsal compartment (second, third, fourth) was recorded in each view. Dorsal tangential view was obtained using a mini C-arm intraoperatively and sending the beam parallel to the dorsal aspect of the wrist in transverse plane.

RESULTS

Of the 125 distal screws, 8 screws were seen to be penetrating the dorsal cortex in lateral and oblique views, whereas 11 screws were detected in dorsal tangential view.

CONCLUSION

The screw penetration to the third dorsal compartment was missed in standard views, but visualized in dorsal tangential view. We recommend the use of dorsal tangential view in addition to standard lateral and oblique views during volar plating of the distal radius.

Computer tomography aided 3D analysis of the distal dorsal radius surface and the effects on volar plate osteosynthesis

The aims of this study were to measure the size of Lister's Tubercle, the extent of the extensor pollicis longus (EPL) groove and the dihedral angle of the distal dorsal radius. Computer tomography scans of 30 forearms were performed by using a 64-slice Siemens SOMATOM Sensation CT system (Resolution 0.6 mm). DICOM raw data were calculated to 3D by MIMICS software (Materialise, Leuven, Belgium). The size of Lister's Tubercle varied from 1.4 to 6.6 mm (average 3.3 mm) in height radial to the tubercle, and from 5.6 to 18.6 mm (average 13.2 mm) in length. The depth of the EPL groove varied from 0.6 to 3.2 mm (average 1.6 mm). The height on the ulnar side, between the depth of the groove and the tip of the tubercle, varied from 2.2 to 5.8 mm (average 3.4 mm). The dihedral angle of the distal dorsal radius varied from 110 degrees to 135 degrees (average 123 degrees). The variations in height of Lister's Tubercle and in depth of the EPL groove are considerable. This needs to be taken into account when performing volar plating of distal radius fractures otherwise screws may inadvertently penetrate the dorsal cortex of the radius potentially leading to EPL rupture.

Perforation of the third extensor compartment by the drill bit during palmar plating of the distal radius

The frequency of penetration into the third extensor compartment when drilling the distal screw holes was assessed for four different palmar distal radius plates in 160 cadaver forearms. Penetration into this compartment occurred in 43%. Different plates had different penetration rates: 3.5 LCP four-hole locking T-plate: 20%, 3.5 LCP three-hole locking plate: 42.5%, 2.4 palmar LCP standard plate and the 2.4 palmar LCP buttress plate: 55%. When using a palmar plate on the distal radius, the surgeon risks penetrating into the third extensor compartment.