Study Design: The effect of Total Hip Replacement surgery (THR) upon spinal sagittal alignment and low back pain was assessed in patients with severe hip osteoarthritis.

Summary of Background Data: Osteoarthritis in the hip joint is associated with abnormal posture and gait due to hip flexion contracture and hip pain. This in turn may cause abnormal spinal sagittal alignment and secondarily induce low back and leg pain. However, there have been no reports regarding the corrective effect of Total Hip Replacement surgery upon spinal sagittal alignment in patients with osteoarthritis of the hip.

Methods: This study prospectively analyzed the results of 25 patients (15 females and 10 males, average age 67.4 years (32–84)) undergoing THR for severe osteoarthritis of the hip. Pre and post-surgical assessment included; sagittal measurement of Sacral Inclination (SI) and total Lumbar Lordosis (L1-S1) on standing lateral radiographs. Functional clinical outcomes for hip as well as low back were also evaluated using the Oswestry back Questionnaire, the Modified Harris Hip Score and Visual Analog Scale for lower back pain and hip pain accordingly.

All the radiographic and clinical evaluations were completed both before THR surgery and 3 months following the surgery during routine follow up.

Results: Mean Lumbar Lordosis before the surgery and in the follow up was 50.36 and 50.32 respectively. Mean sacral inclination before and after surgery were 39.06 and 38.16 respectively. Mean Functional outcomes as assessed by the HHS score before and after the surgery were 45.74 and 81.8 respectively. Mean Oswestry Questionnaire scores before and after the surgery were 36.72 and 24.08 respectively. Mean VAS scores for hip pain before and after the surgery were 7.08 and 2.52 respectively. Mean VAS scores for lower back pain before and after the surgery were 5.04 and 3.68 respectively.

Discussion: No Significant difference was found between the sagittal alignment of the spine before THR and 3 months following it. Interestingly, total hip replacement surgery significantly improved spinal functional outcome as well as relieved low back and hip pain.

During the last 2 decades it has been recognized that scoliosis may start de novo during adult life as a result of advanced degenerative disc disease, osteoporosis or both. In some the degenerative process is superimposed on a previous adolescent curve. Aside from the disfigurement caused by the spinal deformity, pain and disability are usually the major clinical problem.

The prevalence of adult scoliosis rises with age: from 4% before age 45, 6% at age 59 to 15% in-patients older than 60 years. More than two thirds of the patients are females and the prevalence of right lumber curves is higher than in comparable series of patients with adolescent scoliosis.

Adult scoliosis is characterized by vertebral structural changes with translatory shifts i.e. lateral olisthesis accompanied by degenerative disc and facet joint arthrosis.

Although the magnitude of these curves is usually mild (20–30 degrees) lateral spondylolisthesis is observed frequently. It is also common to observe degenerative spondylolisthesis in patients with degenerative lumbar scoliosis. The annual rate of curve progression ranges from 0.3 to 3%.

Patients present with a history of a spinal deformity accompanied by loss of lumbar lordosis, trunk imbalance and significant mechanical back pain. Pain may arise not only from degenerative disc disease and facet arthritis leading to symptoms of spinal stenosis, but also from muscle fatigue due to the altered biomechanics secondary to a deformity in the coronal and sagittal planes. Root entrapment is common and occurs more often on the concavity of the curve. Symptoms of neurogenic claudication are also common in adults with lumbar scoliosis.

Non-operative care includes exercises, swimming, NSAIDs, and occasional epidural injections. Brace treatment can be tried as well. Curve progression as well as axial or radicular pain not responding to non-operative care are indications for surgical intervention.

Surgery may include decompression alone or in conjunction with curve correction and stabilization. Posterior instrumentation may be supplemented with interbody cages. Fusion is usually carried down to L5 but occasional instrumentation to the sacropelvis is mandatory. Problems with a high pseudoarthrosis rate are common with sacral fixation. Even in the best of hands a long recovery period (6–12 month) and moderate pain relief should be expected. As summarized by Dr. Bradford “despite recent advancements evaluation and successful management of patients with adult spinal deformity remains a significant challenge”