Hip-Spine Syndrome refers to a range of disorders, many of which can present themselves as discomfort in the back, despite having their origin in the hip, or hip pain that have their underlying cause in the spine.
As the population ages, hip and spine complaints become more and more frequent. Too often, these conditions present themselves with similar symptoms, making it difficult to determine the true underlying disorder. Is Hip-Spine Syndrome osteoarthritis of the hip causing low back pain, or degenerative lumbar spinal stenosis making itself known as hip discomfort? This article will discuss the primary issues associated with Hip-Spine Syndrome, and the potential risks and benefits of various surgical interventions.1
The potential for parallel pain in the hip and spine results in challenging treatment decisions. Common Hip-Spine Syndrome complaints include back pain with associated discomfort in the buttocks, groin, thigh, and even the knee. Even after the management of one pathology, persistent pain may also demand management of another. Correct diagnosis of both entities is critical and may also aid in the appropriate treatment sequence.2
Understanding the Interrelation Between Hip and Spine
It may help to think of the body as a linkage from the ground up; the feet form the base of the linkage, with the tibia/fibula, femur, hip joint, knee, and pelvis all aligning to form a complete system. Given this interconnectedness, misalignments below the hip joint can also have a direct effect on the spine.
Understanding the linkage and potential for interrelated discomfort is particularly important. Muscle forces acting on the front and back of the abdomen and spine must be balanced. When standing, maintaining symmetry and alignment among the feet, lower extremities, pelvis, spine, and head requires the pelvis to also be balanced front-to-back. To equalize these forces, the pelvis will rotate forward (known as “anteversion”) on standing. When this occurs, the only way to maintain the head’s position over the pelvis is to increase curvature in low back. This curvature, known as “lordosis,” is typically in the range of 55-60° when standing.
When sitting, however, the body requires a broader base. The pelvis rotates to the posterior, (called “retroversion”), and much of the curve in the spine is eliminated in order to keep the head centered. That typical 55-60° curvature decreases to approximately 15° when sitting in a chair. Sitting in a more “slumped” position (watching TV, for instance) may cause the lumbar spine to flatten out to 0°.
The majority of this motion takes place in the lower back. In fact, as much as 70% occurs in the lowermost levels; if the spine experiences a 60° curve when standing, approximately 40° will be found between the L4 and S1 vertebrae (that is, the L4/L5 and L5/S1 levels).
The cumulative effect of a lifetime of motion, or the onset of disease or degeneration, often results in low back pain. The most important response with Hip-Spine Syndrome is to identify the predominant “pain generator”, yet this is often no small task.
For years, fusion was the most common response to pain in the hip, knee, back, or other joint. With the advent of joint replacements in the 1960s, the treatment approach shifted to maintaining motion in the affected joint. Replacement, in other words, enabled the conversion to a painless joint while still maintaining motion. Once proven successful in hips and knees, this approach continued to gain favor in ankles, elbows, the neck, wrists, and even fingers.
In fact, the low back is the only area that continues to see fusion as a primary treatment approach. Surgeons in the U.S. perform more than 1 million spinal fusions each year, with the L4/L5 and L5/S1 being the most common targets. Yet as we learned a moment ago, these joints are also where spinal curvature must take place to enable comfortable standing and sitting. Fusing those joints, in other words, imposes a limitation on one of the most important areas of motion.
For patients diagnosed with spinal disorders—whether they result in low back or hip pain—fusion not only eliminates a key point of mobility, it increases stress above and below the fused level(s). Subsequent mechanical stress on these joints can cause Adjacent Segment Degeneration (ASD), accelerating the need for future surgical intervention.3
Too often in the case of Hip-Spine Syndrome, abnormalities discovered in radiographs or presenting through low back pain result in spinal fusion, a treatment with permanent consequences that could even make things worse if the pathology was located in the hip. In parallel, a hip replacement to address pain or an abnormal radiograph in the hip/pelvic area will fail to bring improvement if the spine was the source of the problem.
One obstacle to effective Hip-Spine Syndrome diagnosis is the fact that primary care physicians, midlevel physicians’ assistants, and nurse practitioners often have little awareness of the issue. Subjective complaints of hip pain often lead to x-rays and hip replacements without a thorough evaluation of other problem sources. Spinal surgery can sometimes follow a similar path. Patients and healthcare providers must carefully consider all potential sources of pathology to avoid poor outcomes.
A physical exam is likely to aid in the correct identification of the pathology; back pain does often originate in the back, and the same is true for the hip, but making that assumption can lead to unnecessary surgical treatment. Given that hip replacements, spinal fusions, and similar surgeries entail significant risk, discomfort, expense, and recovery time, proper diagnosis is paramount.
An Alternative to Spinal Fusion
BalancedBack total joint replacement offers a new treatment option. This innovative approach to the treatment of hip- and back pain can bring the advantages of other joint replacements—such as knees and hips—to some who suffer from Hip-Spine Syndrome. The BalancedBack device addresses the same pathologies as fusion while preserving range of motion, maintaining natural balance, and helping protect adjacent levels from breakdown.
As the first total joint replacement for the lumbar spine, BalancedBack follows closely in the footsteps of other proven replacement procedures, addressing a number of maladies while replacing the function of both the disc and facet joints.
1 Devin, Clinton J. MD; McCullough, Kirk A. MD; Morris, Brent J. MD; Yates, Adolph J. MD; Kang, James D. MD. Hip-spine Syndrome. (2012). JAAOS – Journal of the American Academy of Orthopaedic Surgeons: July 2012 - Volume 20 - Issue 7 - p 434-442 doi: 10.5435/JAAOS-20-07-434.
2 Miyamoto R, Patel RD, Slover J, Razi AE, Buckland AJ. Differentiating Hip Pathology From Lumbar Spine Pathology: Key Points of Evaluation and Management. Instr Course Lect. 2017 Feb 15; 66:315-327.
3 Malhar N. Kumar, Andrei Baklanov, Daniel Chopin. Correlation between sagittal plane changes and adjacent segment degeneration following lumbar spine fusion. Eur Spine J (2001) 10:314–319, DOI 10.1007/s005860000239.