Prior leg length discrepancy in total hip arthroplasty patients causes greater implant complications and faster time to revision

Abstract

Background: Leg length discrepancy (LLD) following total hip arthroplasty (THA) is a common complaint, leading to decreased patient satisfaction. However, the effect of LLD before THA on outcomes and complications is not well defined.

Aim: To assess the effect of prior LLD on rates of falls, implant-related complications, stay length, readmissions, and implant survival following THA.

Methods: A retrospective review of a nationwide insurance database was conducted from 2010 to 2021. All cases of THA and those with a prior diagnosis of LLD were identified. THA patients with LLD were matched to control patients 1:5 based on demographic and comorbidity profiles. Two-year fall rates and implant complications, lengths of stay, 90-day readmissions, and time to revision were compared between cohorts.

Results: A total of 2038 patients with LLD were matched to 10165 control patients. The LLD group showed significantly greater rates of falls [odds ratio (OR) = 1.58; 95% confidence interval (95%CI): 1.24-2.01], dislocation (OR = 2.61; 95%CI: 2.10-3.24), mechanical loosening (OR = 4.58; 95%CI: 3.28-6.29), and periprosthetic fracture (OR = 2.70; 95%CI: 1.96-3.72) compared to the control group (all P < 0.001). Mean length of stay (LOS) was also significantly higher in the LLD group (3.1 days vs 2.8 days, P = 0.034). No significant difference in 90-day readmission rates (7.75% vs 7.02%, P = 0.244) was observed between the groups (P = 0.244). Time to revision was significantly less in the LLD group (225 days vs 544 days, P < 0.001).

Conclusion: LLD in patients having THA is related with significantly higher fall risk, rates of implant-related complications, LOS, and quicker time to revision. Identifying patients with LLD before their THA may help in identifying risks, better patient counselling, and more effective preoperative planning. However, the study have important limitations: Its design lacks information on the degree and cause of LLD, the time between diagnosis and surgery, and which leg with the discrepancy underwent the operation. Future well-designed studies should confirm the findings of this study.

Keywords: Fall risk; Implant complications; Leg length discrepancy; Length of stay; Outcomes; Readmission; Time to revision; Total hip arthroplasty.

Figure 1

Flow diagram of matching criteria between total hip arthroplasty patients with prior leg length discrepancy. LLD: Leg length discrepancy; THA: Total hip arthroplasty; COPD: Chronic obstructive pulmonary disease; DM: Diabetes mellitus; HTN: Hypertension.

Figure 2

Two-year falls and implant-related complication rate following total hip arthroplasty between patients with leg length discrepancy and matched-control patients. ML: Mechanical loosening; PFx: Periprosthetic fracture.