Long-Term Survival Analysis of Low Back Pain Onset in Patients Undergoing Hip Prosthesis Surgery: A Kaplan-Meier Study.

Introduction: Total hip arthroplasty has been associated with the onset of low back pain, which can significantly impact patients' quality of life. However, a detailed evaluation of the time until the onset of long-term low back pain following total hip arthroplasty remains largely unknown. This study aimed to explore the relationship between total hip arthroplasty and the development of long-term lower back pain. Through survival analysis, we examined the time of onset of low back pain in a cohort of patients who underwent the procedure, providing a detailed temporal perspective of this postoperative complication.

Hypothesis: The onset of low back pain in patients undergoing total hip arthroplasty tends to manifest in the medium and long term.

Materials and methods: A survival study using the Kaplan-Meier method was conducted on 299 patients who underwent total hip arthroplasty between 2010 and 2020 at the Hospital Clínico Universitario Lozano Blesa in Zaragoza. The event of interest was the occurrence of low back pain during monthly follow-ups, which was subsequently stratified by sex and body mass index (BMI). Death and the end of the study follow-up were considered as censored data.

Results: The sample comprised 67.6% men and 32.4% women. Additionally, 68.2% of patients were overweight or had grade 1 obesity. During the follow-up of the entire sample, 96 patients developed low back pain, with 28 cases occurring within the first 2 years. The 50% survival of the population without low back pain was established at 39 months, with a mean follow-up of 112.25 months (95% CI 105.87-118.62). Significant differences were observed in the onset of lower back pain in men when considering different BMI grades. However, no significant differences were found between sexes or among different BMI groups when gender was not taken into account.

Discussion: The results of this study provide valuable information on the survival of patients undergoing total hip arthroplasty who experienced low back pain over an extensive follow-up period. These findings have significant implications for clinical practice, indicating that patients undergoing total hip arthroplasty should be informed of this potential risk.

Level of evidence: IV; retrospective case series study.