Radiographic parameters and mechanical complications of articulating vs. non-articulating hip spacers

Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty. Standard treatment for PJI is a two-stage revision surgery with antibiotic-loaded cement spacers to control infection and provide temporary joint stability. This study compares the radiological outcomes and complication rates between articulating and non-articulating hip spacers in patients undergoing treatment for PJI and native joint infections.

We retrospectively reviewed 71 hip spacers (34 articulating, 37 non-articulating) in 38 patients treated between 2004 and 2022. Data on leg length discrepancy, femoral offset, infection control, and mechanical complications were obtained. For infection analysis, only patients treated exclusively with one spacer type were included. After excluding eight patients with mixed spacer types (29 spacers), 30 patients with 42 spacers were included in this subgroup.

Articulating spacers were significantly better at preserving leg length, with a mean discrepancy of -3.7 mm compared to -16.9 mm for non-articulating spacers (p = 0.025). However, non-articulating spacers maintained femoral offset (1.1 vs. 0.7, p < 0.001) closer to physiological offset. The rate of mechanical complications was higher in the articulating spacer group, with spacer dislocations occurring in 45% of cases compared to 10% in the non-articulating group (p = 0.015). There was no difference regarding infection control between both groups.

In this exploratory cohort, non-articulating spacers were associated with fewer mechanical complications, whereas articulating spacers demonstrated better leg length preservation. Given the exploratory nature of this study and its methodological limitations, the observed differences between spacer types should be interpreted cautiously and considered associative rather than causal.