Introduction
With our aging population, hip-spine syndrome is a frequent consideration in the differential diagnosis of back, buttock and hip pain.
Spine surgeons have embraced Spino-Pelvic parameters in surgical decision making for a decade or more. Our Orthopedic hip arthroplasty colleagues have also been analyzing these measurements to optimize acetabular cup placement.
The subspecialties have often used spino-pelvic measurements independent of consideration for the effect of surgical changes on the other.
This case illustrates how circumstances may dictate that both the spine and hip surgeons need to collaborate in shared decision making for patients with hip-spine syndrome.
Methods
A 63 year old retired professional athlete saw the co-authors concerning low back, buttock and right hip pain. He had previous bilateral total hip replacements (left 2012, right 2013) and midline laminectomy L3-5 (2020), done elsewhere.
Post laminectomy, multilevel degenerative changes have progressed. All disc spaces have narrowed with multilevel Modic changes. Grade 1 degenerative spondylolisthesis identified on latest x-ray shifting 2mm from 3-5mm of offset on flexion extension, 18 degree right degenerative scoliosis L1-5, plus spontaneous fusions with anterior/lateral osteophytes L1-4.
Clinically, low back/buttock pain have slowly progressed to a level impacting daily activity but not incapacitating. His original spine surgeon suggested a multilevel surgery including scoliosis correction, osteotomies and multiple level fusion.
Consideration of spino-pelvic parameters became an issue after the patient suffered an episode of subluxation of his right total hip with a squatting exercise during a physiotherapy session, worsening right buttock, hip and groin pain.
Standing, sitting and supine x-rays of the pelvis, hips and spine plus lumbar flexion/extension films were digitized and spino-pelvic parameters analyzed, plus specific acetabular cup orientation and femoral anteversion measurements.
Results
Analysis showed:
Standing right cup anteversion 40˚
Anatomic femoral version 27˚
Pelvic incidence (PI) – lumbar lordosis (LL) mismatch of +19˚(65 – 26)
Discussion
Six spino-pelvic parameters constitute alert conditions for risk of hip dislocation
The patient’s analysis showed only one alert measure (standing cup anteversion 40˚).
Two other parameters are bordering the risk level:
Revision of the right acetabular cup was a consideration, but with 1/6 parameters reaching alert status, revision surgery was elective.
Consideration for sequencing of surgery for back pain vs. hip subluxation arose. Spine deformity surgery was likely to change the spino-pelvic parameters thereby changing the acetabular cup positioning in a revision right total hip. Patient’s symptom level (hip vs spine) played heavily into the shared decision making between the patient, the hip and spine consultants.
Ultimately, the patient decided to defer any spine surgery, which meant that any revision cup placement could be based on the present spino-pelvic analysis.
Hip and spine surgeons must increasingly consider the effect of their surgeries on the other specialties surgical planning.