Lumbar fusion involving the sacrum increases dislocation risk in primary total hip arthroplasty

Abstract

AimsConcurrent hip and spine pathologies can alter the biomechanics of spinopelvic mobility in primary total hip arthroplasty (THA). This study examines how differences in pelvic orientation of patients with spine fusions can increase the risk of dislocation risk after THA.Patients and MethodsWe identified 84 patients (97 THAs) between 1998 and 2015 who had undergone spinal fusion prior to primary THA. Patients were stratified into three groups depending on the length of lumbar fusion and whether or not the sacrum was involved. Mean age was 71 years (40 to 87) and 54 patients (56%) were female. The mean body mass index (BMI) was 30 kg/m2(19 to 45). Mean follow-up was six years (2 to 17). Patients were 1:2 matched to patients with primary THAs without spine fusion. Hazard ratios (HR) were calculated.ResultsDislocation in the fusion group was 5.2% at one year versus 1.7% in controls but this did not reach statistical significance (HR 1.9; p = 0.33). Compared with controls, there was no significant difference in rate of dislocation in patients without a sacral fusion. When the sacrum was involved, the rate of dislocation was significantly higher than in controls (HR 4.5; p = 0.03), with a trend to more dislocations in longer lumbosacral fusions. Patient demographics and surgical characteristics of THA (i.e. surgical approach and femoral head diameter) did not significantly impact risk of dislocation (p > 0.05). Significant radiological differences were measured in mean anterior pelvic tilt between the one-level lumbar fusion group (22°), the multiple-level fusion group (27°), and the sacral fusion group (32°; p < 0.01). Ten-year survival was 93% in the fusion group and 95% in controls (HR 1.2; p = 0.8).ConclusionLumbosacral spinal fusions prior to THA increase the risk of dislocation within the first six months. Fusions involving the sacrum with multiple levels of lumbar involvement notably increased the risk of postoperative dislocation compared with a control group and other lumbar fusions. Surgeons should take care with component positioning and may consider higher stability implants in this high-risk cohort.

Sagittal Spinopelvic Translation Is Combined With Pelvic Tilt During the Standing to Sitting Position: Pelvic Incidence Is a Key Factor in Patients Who Underwent THA

“…Recent literature has reported the postural changes from standing to sitting, which can tremendously affect the stability of total hip arthroplasty (THA) [1][2][3][4][5][6]. The pelvis kinematics in standing to sitting transition is commonly considered as a rotation around the axis that connects the center of the 2 femoral heads (hip axis).…”

Dual-Mobility Constructs in Primary Total Hip Arthroplasty in High-Risk Patients With Spinal Fusions: Our Institutional Experience

“…Dislocation remains one of the most common early complications after posterolateral primary THA [1][2][3]16]. There is growing evidence that patients who underwent spinal fusion are at the highest risk for postoperative dislocation, with some reports of up to a 10% dislocation rate [4][5][6][7][8][9][10][11][12][13][14]. The spinopelvic immobility in these patients can lead to bony impingement, causing postoperative instability [8,10].…”

“…In the present study, high-risk patients with prior spinal fusions undergoing primary posterolateral THA with a DM construct did not experience any dislocations at a mean of 3 years of follow-up (range, 1-7 years). There is growing evidence that this patient population is at significant risk of postoperative dislocation [4][5][6][7][8][9][10][11][12][13][14]. In a matched propensity study, Perfetti et al [6] reported a sevenfold increased rate of postoperative dislocation in patients who underwent prior spinal fusion compared with controls.…”

“…Furthermore, patients who underwent fusions of 3 to 7 levels had a 3-fold increased rate of dislocation [5]. In a matched control analysis, Salib et al [11] found that fusion to the sacrum with multiple lumbar level involvement was nearly a 5-fold risk of dislocation compared with controls without a spinal fusion. Therefore, the importance of determining the optimal construct to maximize hip stability and minimize complications in high-risk patients who underwent spinal fusion is of significant importance.…”

“…The patients in this series had multiple levels fused, a high number of fusions to the sacrum, and a range of acetabular component positions. As such, based on growing literature, these patients are particularly at high risk for postoperative instability, with rates reported up to 10% [4][5][6][7][8][9][10][11][12][13][14]. Although more patients and extended follow-up are required, the increased utilization of DM constructs may reduce the dislocation rate of high-risk patients who underwent spinal fusion patients and undergoing primary THA.…”