Degenerative Lumbar Spine Disease, Not Fusion, May Be a Risk Factor for Instability after Total Hip Arthroplasty

Abstract

Dislocation rates after total hip arthroplasty (THA) in patients with fixed spinopelvic motion have been reported as high as 20%. Few studies exist specifically for lumbar spine degenerative joint disease (DJD) and its relationship to THA instability. There were two study objectives: (1) report the incidence of lumbar spine DJD and previous lumbar spine fusion and (2) evaluate the relationship of these two conditions and other potential risk factors to postoperative dislocation after THA. We retrospectively reviewed 818 consecutive THAs performed by a single surgeon utilizing a posterior approach. Comprehensive medical chart and radiographic review was performed to identify patients with lumbar spine DJD and lumbar spine fusion. Radiographic measurements, patient factors, surgical factors, and incidences of dislocation also were recorded. Eight hundred and twelve THAs were analyzed. There were 10 dislocations (1.2%, 10/812). Lumbar spine DJD and previous lumbar spine fusion occurred in 33.4% (271/812) and 5.9% (48/812) of patients, respectively. Lumbar spine DJD, acetabular protrusio, and female sex were significant predictors of dislocation using a Firth penalized maximum likelihood estimation specifically for rare events (area under receiver-operator characteristic curve = 0.91, 95% confidence interval 0.86, 0.96). Interestingly, only 2 of 10 dislocations had a previous lumbar spine fusion. Lumbar spine DJD, acetabular protrusio, and female sex were significant predictors of dislocation, while lumbar spine fusion was largely unrelated. This study used data available to most practicing surgeons and provides useful information for counseling patients preoperatively.

Instability in Patients With Lumbar Spine Disease Undergoing Posterior Approach and Lateral Approach Primary Total Hip Arthroplasty

“…Acetabular cup inclination angle (in degrees) was measured as the angle between a line connecting the superior and inferior ellipses of the acetabular cup relative to the inter-teardrop line, as previously described. 9 Acetabular cup version (in degrees) was measured for the cohort of patients who suffered a postoperative dislocation only to evaluate any acetabular cup retroversion using a validated system (Martell Hip Analysis Suite) from methodology previously described. 20…”

“…[4][5][6][7] Hip instability has been reported to occur in up to 20% of patients who have lumbar spine DJD or fusion. 8,9 A surgical approach has also been increasingly studied regarding postoperative instability because the direct anterior approach continues to gain popularity with early reports of lower dislocation rates. [10][11][12] Historically, the posterior approach without modern capsular repair techniques was associated with an increased risk of dislocation compared with other techniques.…”

“…13 However, a modern posterior approach characterized by extensive capsular repair and external rotator reconstruction has shown to be comparable with other surgical approaches for dislocation rates. 9,[14][15][16] Although the presence of lumbar spine DJD and surgical approach have shown to be independently associated with postoperative dislocation, few studies have investigated the effect of lumbar spine DJD and surgical approach together on hip stability. 17 Understanding the relationship between the presence of lumbar spine DJD, surgical approach, and postoperative dislocation is important for orthopaedic surgeons to limit the occurrence of postoperative dislocation.…”

“…4-7 Hip instability has been reported to occur in up to 20% of patients who have lumbar spine DJD or fusion. 8,9…”

“…13 However, a modern posterior approach characterized by extensive capsular repair and external rotator reconstruction has shown to be comparable with other surgical approaches for dislocation rates. 9,14-16…”