Lumbar fusion is known to reduce the variation in pelvic tilt
between standing and sitting. A flexible lumbo-pelvic unit increases
the stability of total hip arthroplasty (THA) when seated by increasing
anterior clearance and acetabular anteversion, thereby preventing
impingement of the prosthesis. Lumbar fusion may eliminate this protective
pelvic movement. The effect of lumbar fusion on the stability of
total hip arthroplasty has not previously been investigated. The Medicare database was searched for patients who had undergone
THA and spinal fusion between 2005 and 2012. PearlDiver software
was used to query the database by the International Classification
of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedural
code for primary THA and lumbar spinal fusion. Patients who had
undergone both lumbar fusion and THA were then divided into three
groups: 1 to 2 levels, 3 to 7 levels and 8+ levels of fusion. The
rate of dislocation in each group was established using ICD-9-CM codes.
Patients who underwent THA without spinal fusion were used as a
control group. Statistical significant difference between groups
was tested using the chi-squared test, and significance set at p
<
0.05.Aims
Patients and Methods
