Overlapping symptoms of lumbar stenosis and hip osteoarthritis can often lead to misdiagnosis and improper treatment. In addition to this, concurrent disease of the lumbar spine and the hip are relatively common in the elderly population. Addressing this disease process, Offierski and Macnab coined the term hip-spine syndrome in a 1983 paper [1]. In this paper, hip-spine syndrome was further classified as simple, complex, or secondary. Simple hip-spine syndrome cases were defined as those with one clear source of disability causing symptoms in both the hip and the spine [1]. Complex cases were defined as those whose symptoms were derived from a disease process both within the spine as well as the hip [1]. Lastly, secondary cases were defined as those with inter-related pathologies, such as a fixed flexion hip deformity causing an exaggerated lumbar lordosis [1].
More recent research has aimed at gaining a better understanding of this disease process while looking for more effective ways to properly diagnose and treat. The first step to a diagnosis is a thorough history and physical. Traditionally, leg and buttock pain are indicative of a lumbar pathology whereas groin pain is more indicative of a hip pathology [2]. This alone is not definitive as significant overlap exists, with 76% of hip osteoarthritis causing symptoms in the buttock and 43% in the posterior thigh [3]. In order to properly differentiate the primary source of symptoms, physical exam findings in conjunction with several imaging modalities may be necessary [2]. A forward bend test is a useful tool in the physical exam. In a patient’s attempt to achieve lumbar extension while standing, radicular pain may indicate a lumbar pathology [2]. Range of motion testing is an important factor to assess hip function, as limited internal rotation of the hip has shown to increase the likelihood of the pathology being in the hip rather than the spine by 14 times [4]. After physical exam, plain film x-ray is first line for diagnosis. Despite being a useful modality, x-ray alone may fail to differentiate hip and spine pathology. An example of this was presented by Singh et al. where x-ray failed to document a case of hip fracture as well as a case of avascular necrosis [5]. Cases such as these may require MRI or CT for proper diagnosis.
The treatment sequence of patients with hip-spine syndrome is predicated on the primary source of the disease. There is evidence suggesting that sciatica and lumbar stenosis may be over diagnosed and hip osteoarthritis may be underdiagnosed [6]. Parvizi et al. presented a study of 344 patients with hip osteoarthritis who underwent total hip arthroplasty (THA) [7]. One hundred seventy of the patients also had lower back pain. Of those with low back pain, 66.4% had total symptom resolution [7]. Similarly, Ben-Galim et al. reported improvement in hip and back scores in 25 patients with hip osteoarthritis as well as low back pain that underwent THA [8].
In summary, a detailed investigation of the primary source of symptoms in patients with hip-spine syndrome is essential in obtaining the correct diagnosis and treatment sequence. In complex cases, diagnostic imaging including MRI or CT can be useful in assisting the physician in identifying the primary pathology. After diagnosis and treatment, symptoms such as low back pain may persist. Persistent symptoms should be investigated and treated accordingly, as hip and spine pathology often coexist.
