Summary Hip-spine syndrome (HSS) refers to the coexistence of degenerative conditions affecting both the hip joint and lumbar spine, where pathology in one region can influence symptoms and biomechanics in the other. The condition typically presents in adults and the elderly and presents with low back pain (LBP) associated with buttock, groin, thigh, and knee pain. Diagnosis is made with a combination of clinical history, thorough physical examination including provocative tests, plain radiographs, and often advanced imaging or diagnostic injections to delineate the primary pathology. Treatment is usually nonoperative initial management involving physical therapy or diagnostic/therapeutic injections. Operative treatment (such as total hip arthroplasty or spinal decompression/realignment) is indicated when the primary source of pain is identified and conservative measures fail, or when severe lumbar stenosis is present alongside hip pathology. Epidemiology Incidence common in older adults 32.5% of patients over 50 undergoing spine surgery have concurrent hip and spine pathology 20-30% of patients with hip OA also have significant lumbar spine pathology Demographics increasingly common with age some studies suggest higher prevalence in women Risk factors increasing age older age is strongest risk factor for degenerative changes in both the hip and the spine prior spinal surgery lumbar fusion increases the risk of hip instability and dislocation after THA spinopelvic malalignment abnormal sagittal balance and pelvic incidence are associated with hip-spine syndrome Etiology Pathophysiology pathologic spinopelvic biomechanics alteration in either the hip or the lumbar spine will affect the other login to view 1 more bullet decreased hip range of motion forces increased motion to occur at the lumbar spine to allow function and attempt to maintain sagittal balance decreased motion at the lumbar spine similarly forces increased stress on the hip joint login to view 1 more bullet Anatomy Bony anatomy lumbar spine vertebral bodies login to view 2 more bullets facet joints sacrum login to view 2 more bullets pelvis login to view 2 more bullets proximal femur login to view 1 more bullet Arthrology intervertebral discs fibrocartilaginous structures separate the vertebral bodies. Composed on inner nucleus pulposus (type II collagen) and the outer annulus fibrosus (type I collagen) providing shock absorption, allowing spinal motion, and maintaining height facet joints (zygapophyseal joints) paired synovial joints connect the inferior articular process of the upper vertebra with the superior articular process of the lower vertebra sacroiliac joint synovial joint between iliac portions of the pelvis and the sacrum allowing a small amount of motion hip joint a ball and socket synovial joint formed by the femoral head and acetabulum ligaments: iliofemoral, pubofemoral, and ischiofemoral provide stability and limit excess motion labrum: a triangular fibrocartilaginous ring that deepens the acetabulum and enhances joint stability Lumbar nerve roots L1 dermatome: groin, upper thigh myotome: hip flexion L2 dermatome: upper thigh, medial knee myotome: hip flexion, knee extension L3 dermatome: lower thigh, medial knee myotome: knee extension L4 dermatome: medial leg, foot myotome: knee extension, ankle dorsiflexion L5 dermatome: lateral leg, dorsal foot myotome: hip abduction, ankle dorsiflexion, toe extension S1 dermatome: lateral foot, heel myotome: hip extension, knee flexion, plantarflexion Biomechanics normal spinopelvic biomechanics spine and pelvis work in tandem to maintain sagittal balance and enable smooth transition between postures when standing, the pelvis is either neutral or has a slight anterior tilt (flexed, decreased PT), while the lumbar spine maintains a natural lordotic curve (increased LL) when sitting, the pelvis tilts posteriorly (extended, increasing PT) and the lumbar spine flexes (decreasing LL) radiographic parameters sagittal vertical axis (SVA) login to view 1 more bullet pelvic incidence (PI) login to view 3 more bullets sacral slope (SS) login to view 2 more bullets pelvic Tilt (PT) login to view 2 more bullets lumbar lordosis (LL) login to view 3 more bullets Classification Offierski and MacNab Hip-Spine Syndrome Classification Simple Despite apparent pathologic changes in both the hip and the spine, the primary source of symptoms is easily elicited and clearly attributed to either the hip or the spine. Treatment of the one improves symptoms. Secondary Hip and spine pain are interdependent in such a way that the symptoms of one are secondary to a deformity or pathology in the other. Complex Concurrent pathologic changes in the hip and the spine with no clear primary source of pain. Misdiagnosed A patient with pathology in both areas who undergoes inappropriate treatment of the one, leading to poor clinical response, while the true source of pain is later recognized to have been the other. Presentation Overview diagnostically challenging due to the significant overlap of symptoms originating from the hip and the spine clinicians should maintain high index of suspicion for concurrent pathology when evaluating the hip or the spine< Symptoms hip symptoms groin pain login to view 2 more bullets buttock pain login to view 1 more bullet C-sign login to view 1 more bullet limp referred knee pain login to view 1 more bullet pain with hip range of motion pain putting on shoes/socks pain getting in and out of the car inability to lie on patients side login to view 1 more bullet lumbar spine symptoms lower back pain login to view 1 more bullet burning pain or electric shock character of pain login to view 1 more bullet pain that begins and worsens with ambulation, is relieved by sitting login to view 1 more bullet shopping cart sign login to view 2 more bullets stiffness login to view 1 more bullet Physical exam hip physical exam reproduction of pain in the affected hip with weight bearing Stinchfield test login to view 1 more bullet ROM testing login to view 2 more bullets FABER login to view 3 more bullets FADIR login to view 2 more bullets log roll gait analysis login to view 2 more bullets spine physical exam ROM login to view 2 more bullets palpation for tenderness login to view 2 more bullets radicular findings login to view 6 more bullets gait analysis login to view 4 more bullets neurologic examination login to view 3 more bullets spinal alignment Imaging Radiographs hip radiographs weight bearing AP pelvis and lateral hip radiographs login to view 6 more bullets standing and seated lateral spine/ pelvis radiographs assessing spinopelvic mechanics lumbar spine radiographs standing AP and lateral login to view 1 more bullet flexion and extension views login to view 1 more bullet spinal alignment films full-length, 36-inch sagittal spinopelvic radiograph EOS imaging login to view 1 more bullet radiographic parameters sagittal vertical axis (SVA) login to view 1 more bullet pelvic incidence (PI) login to view 3 more bullets sacral slope (SS) login to view 2 more bullets pelvic Tilt (PT) login to view 2 more bullets lumbar lordosis (LL) login to view 3 more bullets CT CT myelography neural impingement MRI study of choice for superior detail CT myelography reserved for patients with preexisting spinal hardware to avoid distortion in MRI MRI lumbar spine MRI can reveal disc degeneration, herniation, stenosis, and nerve root compression hip MRI can reveal labral tears, cartilage loss, bone marrow edema, soft tissue pathology early findings of osteonecrosis may only be visualized on MRI MRI arthrogram best modality for hip labral tear useful for accult femoral neck fracture, infection, or tumor as the cause of pain Studies Diagnostic injections intraarticular hip injections with local anesthetic can confirm the hip as a source of pain in symptoms improve significantly fluoroscopic guidance typically recommended reserved for patients with radiographic evidence of hip OA due to potential toxicity to chondrocytes patients experiencing >50% pain relief following intraarticular hip injection are likely to have successful outcome following THA. 87-96% sensitivity; 100% specificity selective nerve root blocks or epidural injections can help ID spine-related symtpoms improvedment in primary symptoms following ESI can confirm stennsis as primary pain generator ESI has potential for long term complications and lacks long term efficacy and should therefore only be used for diagnostic purposis in patients with findings indiating lumbar stensosi as primary pain generator Electrophysiologic studies useful when diagnosis remains unclear normal findings do not rule out spinal pathology bilateral polyradiculopathy at multiple levels suggestive of DLSS Treadmill test functional assessment of lumbar stenosis Differential Isolated hip osteoarthritis groin pain on PE pain with putting on socks/shoes limited hip internal rotation positive Stinchfield Isolated nonarthritic hip pathology femoroacetabular impingement and labral tears groin pain (positive in up to 92% of patients with FAI) positive FADIR (positive in up to 88% of patients with FAI) plain radiographs and MRI arthrogram used for suspected FAI/labral tears greater trochanteric pain syndrome trochanteric bursitis, external snapping hip, gluteus minimus/medius dysfunction pain with palpation over the lateral hip positive Ober test Trendelenburg gait MRI to evaluate abductor function stress fractures more common in long-distance runners, patients with metabolic bone diseases, or long-term bisphosphonate therapy pain worsens with weight-bearing, improves with rest MRI or Technetium bone scan for diagnosis Isolated lumbar spine pathology radiculopathy disk herniation, spondylolisthesis, foraminal stenosis, or facet cysts L1-L3 nerve root radiculopathy may cause groin pain L5 radiculopathy may cause buttock, lateral hip, and thigh pain electric shock-like pain radiating to lower extremity motor weakness, sensory deficits, absent reflexes possible straight leg raise test and contralateral straight leg raise test MRI, CT myelography, EMG used for diagnostic imaging selective nerve-root block can help confirm diagnosis neurogenic claudication buttock or posterior thigh pain with ambulation thigh and/or leg aching, weakness, heaviness with ambulation spondylolysis/Spondylolisthesis spondylolysis may cause unilateral or bilateral low back pain with radiation to the buttocks spondylolisthesis may cause start-up low back pain radiculopathy common oblique lumbar radiographs may demonstrate pars defect CT used for diagnosis of spondylolysis standing, flexion-extension radiographs of lumbar spine used for subtle instability sacroiliac joint pathology unilateral or bilateral buttock pain pain worse with downhill walking or wearing a tight belt tenderness over SI joint positive FABER test SI joint injection can aid in diagnosis peripheral vascular disease findings: login to view 1 more bullet ankle-brachial index login to view 2 more bullets internal iliac artery claudication: Leriche Syndrome login to view 1 more bullet duplex ultrasonography used for further evaluation pelvic pathology metastasis Paget disease sacral insufficiency fractures peripheral neuropathy meralgia paresthetica shingles knee osteoarthritis lumbar spine pathology and hip pathology can both radiate to the knee radiographs (standing AP, lateral, patellofemoral views) and physical examination useful to delineate intraarticular knee injections diagnostic and therapeutic for primary pain generator Treatment Nonoperative observation +/- physical therapy, anti-inflammatory medications first line of treatment therapy focused on maintaining or improving range of motion in both regions, strengthening hip and core musculature, and gait training weight loss reduces stress on both weight-bearing joints injections intraarticular hip steroid injection login to view 1 more bullet epidural steroid injection login to view 1 more bullet Operative isolated treatment of hip or spine pathology may be indicated, depending on diagnostic workup either approach first may potentially exacerbate the other’s symptoms in the setting of increased ambulation and activity staging or sequencing the treatment is most commonly used. Must consider: dominant symptoms neurologic risk spinopelvic mobility biomechanical effects of treating one pathology on the other hip-first approach indications login to view 4 more bullets techniques login to view 2 more bullets outcomes login to view 1 more bullet spine-first approach indications login to view 5 more bullets techniques login to view 4 more bullets outcomes login to view 2 more bullets simultaneous surgery rarely performed requires coordination of hip surgeon, spine surgeon, and anesthesia Techniques Total Hip Arthroplasty indication radiographic evidence of hip OA physical exam findings consistent with hip OA significant relief with intra-articular hip injection approach anterior, posterior, or anterolateral acceptable posterior approach historically allowed for greater flexibility in component position, however, higher incidence of dislocation considerations / technique typical acetabular safe zones (anteversion of 15 +/- 10, inclination of 40 +/- 10) may not be applicable surgeons should assess sagittal alignment and spinopelvic motion login to view 3 more bullets spinal stiffness: change in sacral slope < 10 degrees login to view 1 more bullet head size should be maximized to increase stability dual-mobility implants for high-risk patients login to view 2 more bullets THA surgeons should consider the effect of spinal surgery on the orientation of the acetabular cup in preop plan for THA, if spinal realignment sugery planned to follow robotics or navigation help surgeons dial in ideal anteversion and inclination outcomes stiff spine (change in SS < 10 degrees) increases dislocation risk after THA Hip arthroscopy indications FAI, labral tears, chondral lesions younger, or middle-aged patients minimal or no hip arthritis hip dominant symptoms diagnostic hip injection to confirm hip as primary pain generator considerations / technique avoid over-resection to destabilize hip repair of capsule is critical outcomes inferior in the presence of spine pathology (lumbar stenosis, sagittal imbalance) Lumbar decompression alone indications symptomatic spinal stenosis neurogenic claudication radiculopathy from disc herniation or central/lateral recess stenosis no instability or deformity preserved sagittal alignment approach open vs minimally invasive vs microscopic techniques laminectomy laminotomy foraminotomy outcomes less predictable outcomes in the setting of hip-spine syndrome minimal impact on hip biomechanics many studies suggest lower satisfaction rates in the setting of coexisting hip pathology safer than fusion prior to THA Lumbar spinal fusion (LSF) indications spondylolisthesis instability segmental deformity mechanical back pain refractory to nonoperative treatment recurrent stenosis after failure of decompression alone considerations / technique fusion will fundamentally change spinopelvic mechanics, increasing stress on the hip joint and adjacent spinal levels login to view 1 more bullet any adjustment to LL will influence/decrease compensatory mechanism at the hip and pelvis hip flexion contractures may force a spine to be fused in less lordosis to allow sagittal balance if preceding THA, anticipate modified cup position or dual-mobility implant outcomes up to 15-20% of LSF patients require subsequent THA after fusion increased risk of hip dislocation after THA due to altered spinopelvic mechanics login to view 4 more bullets Lumbosacral fusion (L5-S1 +/- pelvis) indications fixed sagittal imbalance high-grade spondylolisthesis L5-S1 degenerative disc disease considerations / technique lumbosacral fusion creates minimal compensation when sitting outcomes highest risk of THA dislocation with lumbosacral fusion login to view 1 more bullet Complications Hip Arthroplasty Dislocation elevated risks with spinal stiffness increased with prior fusion or fixed deformity up to 8-10% THA dislocation rate treatment dual mobility constructs or constrained liners THA impingement increased risk in HSS due to spinal pathology limiting THA mobility Leg-length discrepancy particularly at risk in THA patients with large coronal spinal deformities Adjacent segment degeneration gait abnormalities from untreated hip disease can stress spinal hardware and contribute to adjacent segment degeneration Persistant pain 30% lower satisfaction rates in patients undergoing lumbar surgery with unrecognized hip disease Prognosis Natural history of disease / Prognosis without treatment poor, due to the progressive degenerative nature of the disease up to 50% of patients will eventually require surgical intervention Prognostic variable favorable younger age (<75) increased spinopelvic mobility milder pathology accurate diagnosis is most critical prognostic factor negative older age medical comorbidities spinopelvic stiffness Survival with treatment up to 80% excellent outcomes when appropriate diagnosis made only 30-50% of patients improved when primary generator is not addressed THA alone: up to 66% of patients with HSS have significant resolution of back pain after THA