HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS

Madurawe C, Vigdorchik J, Lee G, et al. HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS. Orthop Procs. 2021;103-B(SUPP_1):6-6. doi:10.1302/1358-992X.2021.1.006

Madurawe, C., et al. “HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS.” Orthopaedic Proceedings, vol. 103-B, no. SUPP_1, 2021, pp. 6-6., https://doi.org/10.1302/1358-992X.2021.1.006

Madurawe, C., Vigdorchik, J., Lee, G., Jones, T., Dennis, D., Austin, M., Pierrepont, J., & Huddleston, J. (2021). HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS. Orthopaedic Proceedings, 103-B(SUPP_1), 6-6. https://doi.org/10.1302/1358-992X.2021.1.006

Madurawe, C., Vigdorchik, J., Lee, G., Jones, T., Dennis, D., Austin, M. et al. (2021) “HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS.” Orthopaedic Proceedings, 103-B(SUPP_1), pp. 6-6. Available at: https://doi.org/10.1302/1358-992X.2021.1.006

Madurawe, C., J. Vigdorchik, G.C. Lee, T. Jones, D. Dennis, M. Austin, J. Pierrepont, and J. Huddleston. “HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS.” Orthopaedic Proceedings 103-B, no. SUPP_1 (2021): 6-6. https://doi.org/10.1302/1358-992X.2021.1.006

Madurawe C, Vigdorchik J, Lee G, Jones T, Dennis D, Austin M, et al. HIGH PREVALENCE OF SPINOPELVIC RISK FACTORS IN PATIENTS WITH POSTOPERATIVE HIP DISLOCATIONS. Orthop Procs. 2021 Feb 1;103-B(SUPP_1):6-6. https://doi.org/10.1302/1358-992X.2021.1.006

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Abstract

Introduction

Excessive standing posterior pelvic tilt (PT), lumbar spine stiffness, low pelvic Incidence (PI), and severe sagittal spinal deformity (SSD) have been linked to increased dislocation rates. We aimed to compare the prevalence of these 4 parameters in unstable and stable primary Total Hip Arthroplasty (THA) patients.

Methods

In this retrospective cohort study, 40 patients with instability following primary THA for osteoarthritis were referred for functional analysis. All patients received lateral X-rays in standing and flexed seated positions to assess functional pelvic tilt and lumbar lordosis (LL). Computed tomography scans were used to measure pelvic incidence and acetabular cup orientation. Literature thresholds for “at risk” spinopelvic parameters were standing pelvic tilt ≤ −10°, lumbar flexion (LL_stand – LL_seated) ≤ 20°, PI ≤ 41°, and sagittal spinal deformity (PI – LL_stand mismatch) ≥ 10°. The prevalence of each risk factor in the dislocation cohort was calculated and compared to a previously published cohort of 4042 stable THA patients.

Results

Median supine cup inclination for the dislocating cohort was 43° (range, 26°- 58°). Median cup anteversion was 23° (range, 7° − 40°) for the dislocating cohort. 65% of the dislocating patients had socket positions within the Lewinnek safe zone (Figure 1). Standing PT (-10° v −1°), lumbar flexion (20° v 45°), and PI-LL mismatch (12° v −1°) were all significantly different (p < 0.001) in the dislocating group compared to the stable THA population (Figure 2). There was no difference in PI between the dislocating group and the stable THA population (58° v 56° respectively, p = 0.33), with the numbers available. 80% of the dislocating patients had one or more of the 3 statistically significant risk factors, compared to only 24% of the stable THA population.

Conclusion

Excessive standing posterior pelvic tilt, low lumbar flexion and a severe SSD are highly prevalent in unstable THAs. Pre-op screening for these parameters may reduce the prevalence of dislocation.

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