Risk of extrapelvine vascular injuries in osteosynthesis with gliding hip screws

Dynamic hip screw (DHS) osteosynthesis represents one of the most frequently performed fixation methods in orthopedic practice. The purpose of this study was to determine the potential risk of vascular damage by DHS side-plate screws (PS) and plunging instruments for individual femoral vessels and screw positions.

In ten hemipelvic/leg specimens mounted with a large femur distractor, a DHS system with a four-hole side-plate was inserted. PS were inserted in 3 consecutive courses with different inclinations in the frontal plane of 0° (group 1), - 30° posterior (group 2) and + 30° anterior (group 3) in relation to the side-plate's surface, resulting in 120 PS positions. After screw tightening, the soft tissues on the medial side of the femur were dissected and investigated for vascular compromise; in each course, the effect of overshot instruments within a range of 50 mm beyond the side-plate's surface was also tested.

Totally, 37/120 screw positions (31%) revealed potential vascular compromise which comprised of 15/120 (13%) direct hits by screw tips and 22/120 (18%) potential impacts by plunging instruments. The deep femoral artery system (DFA) was significantly (p = 0.007) most often affected but no significant differences for individual vascular structures were seen. Direct vascular impacts occurred significantly more often (p = 0.0047) in screws with 0° inclination compared to + 30° inclination (p = 0.017). Significant differences among individual screw positions were only found in group - 30° with direct vessel contacts (p = 0.038).

The DFA system is significantly more at risk while significant preference of a certain vessel is missing. Our data indicate that more than 30% of 120 screw positions in DHS osteosynthesis revealed a potential danger of vascular compromise, when surgical principles are denied in hip fracture fixation.

Though vascular complications are infrequently encountered in DHS osteosynthesis they have to be considered as a potential complication when surgical principles are not followed in this anatomic area.