How Effective Are Constrained Liners at Preventing Dislocation After Revision Total Hip Arthroplasty?

Abstract

Recurrent instability continues to challenge arthroplasty surgeons, and constrained liners may be utilized for cases of recurrent or multidirectional instability following revision total hip arthroplasty (rTHA). The purpose of this study was to evaluate dislocation rates and survivorship after rTHA using constrained liner (CL) prostheses. Patients who underwent rTHA using a CL prosthesis were retrospectively reviewed from January 1, 2013, to December 31, 2024. Patients who had antibiotic spacers or megaprostheses, or those who had less than one year of follow-up, were excluded. Survivorship analyses were performed to determine dislocation and reoperation-free survivorship through follow-up. A total of 98 rTHAs with CL were included, with a mean follow-up time of 3.9 years (range, one to 10.8). The CL dislocation rate at final follow-up was 16.3% (16 of 98), and the nine-year dislocation-free survivorship was 71% (95% confidence interval (CI) [57 to 89]). There was no statistically significant difference in nine-year dislocation-free survivorship among CL systems (P = 0.73), CLs inserted into cups that were retained versus revised (P = 0.95), nor CLs that were snapped in versus cemented (P = 0.38). The overall reoperation rate at final follow-up was 49.0% (48 of 98), and the nine-year all-cause reoperation-free survivorship was 33% (95% CI [17 to 62%]). Of those 48 requiring reoperation, 27 (56.2%) were for infection and 14 (29.2%) were for recurrent hip instability. There was no statistically significant difference in nine-year all-cause reoperation-free survivorship among CLs inserted into cups that were retained versus revised (P = 0.67) nor CLs that were snapped in versus cemented (P = 0.34). In a cohort where a majority of patients had multiple prior rTHAs secondary to hip instability, CLs were a salvage option for preventing repeat dislocation; however, dislocation and reoperation rates remain high.