Sacral Fracture from a Fall: Signs, Treatment, and Recovery

A fall can result in various injuries, and one particularly vulnerable area is the sacrum—the triangular bone at the base of the spine. A fracture in this region can cause significant pain and mobility issues, sometimes affecting nerve function. Though more common in older adults and those with osteoporosis, sacral fractures can occur in anyone who experiences a high-impact fall.

Recognizing the signs early and seeking appropriate treatment are essential for recovery.

Mechanisms Of Injury

A sacral fracture from a fall typically results from direct axial loading or indirect force transmission through the pelvis. Positioned between the lumbar spine and the pelvis, the sacrum absorbs substantial mechanical stress during impact. When an individual falls onto their buttocks, force is transmitted through the ischial tuberosities and sacroiliac joints, concentrating pressure on the sacral bone. The extent of injury depends on factors such as the height of the fall, the surface of impact, and bone density.

In younger individuals with normal bone integrity, sacral fractures often stem from high-energy trauma, such as falls from significant heights or motor vehicle accidents. In contrast, older adults, particularly those with osteoporosis, may sustain fractures from low-energy falls, such as slipping from a standing position.

The biomechanics of sacral fractures also involve rotational and shearing forces, particularly when a fall occurs at an angle. If an individual lands asymmetrically, one side of the pelvis may experience greater force transmission, leading to vertical sacral fractures. A direct fall onto the lower back can generate compressive forces that result in transverse fractures. The sacrum’s composition—both cancellous and cortical bone—affects how fractures propagate. Cancellous bone, being more porous, is prone to compression fractures, while cortical bone, which is denser, may develop linear fractures under extreme stress.

Pre-existing conditions such as osteopenia, previous pelvic fractures, or sacroiliac joint dysfunction can further influence fracture patterns. Individuals with compromised bone strength may experience insufficiency fractures, where normal physiological stress leads to structural failure. These fractures often develop gradually and may be misdiagnosed as lower back pain or sciatica. High-impact falls can result in comminuted fractures, where the sacrum shatters into multiple fragments, increasing the risk of instability and neurological complications.

Types Of Sacral Fractures

Sacral fractures are classified based on their orientation and severity, which influence treatment options and recovery time.

Transverse

A transverse sacral fracture runs horizontally across the sacrum, typically from direct axial loading or a fall onto the lower back. These fractures often involve the S1-S3 vertebral levels and can be stable or unstable depending on whether they extend into the sacroiliac joints. Stable fractures may heal with conservative management, while unstable ones may require surgery.

Transverse fractures are commonly associated with high-energy trauma, such as falls from significant heights or motor vehicle accidents. If the fracture disrupts the sacral foramina, nerve root compression may occur, leading to numbness, weakness, or bowel and bladder dysfunction. A study in The Journal of Bone and Joint Surgery (2021) found that transverse fractures with neurological involvement often require surgical decompression to prevent long-term deficits. Weight-bearing restrictions are typically advised during healing to prevent displacement.

Vertical

Vertical sacral fractures extend longitudinally, often resulting from lateral compression forces. These fractures frequently occur alongside pelvic ring injuries as force transmits asymmetrically through the pelvis. Unlike transverse fractures, vertical fractures can cause significant instability, particularly if they involve the sacroiliac joint or extend into the lumbosacral junction.

Patients may experience unilateral sacral pain, difficulty bearing weight, and pelvic asymmetry. A retrospective study in Spine (2022) found that vertical fractures are more common in individuals with osteoporosis, as weakened bone structure increases susceptibility to low-energy falls. In younger individuals, these fractures are often seen in high-impact trauma cases. Treatment depends on displacement severity, with minimally displaced fractures managed conservatively, while displaced fractures may require percutaneous sacroiliac screw fixation.

Comminuted

Comminuted sacral fractures involve multiple fragments and typically result from high-energy trauma, such as falls from extreme heights or crush injuries. These fractures pose a greater challenge due to their complexity and potential instability. Some fractures remain contained within the sacral body, while others extend into the sacroiliac joints or lumbosacral articulation.

Due to their severity, comminuted fractures often cause significant pain and functional impairment. A multicenter study in The Journal of Orthopaedic Trauma (2023) reported that these fractures are more likely to require surgical stabilization, particularly when associated with pelvic ring disruptions. Techniques such as lumbopelvic fixation or sacral bar placement may be used to restore structural integrity. Recovery can be prolonged, with rehabilitation focusing on pain management and gradual weight-bearing progression to prevent complications.

Neurological Involvement

The sacrum houses the sacral plexus, a network of nerves responsible for motor and sensory function in the lower extremities, as well as autonomic control of the bladder and bowel. Fractures that extend through the sacral foramina or central canal can directly impinge on these nerves, leading to neurological deficits ranging from mild sensory disturbances to significant motor dysfunction or loss of sphincter control.

The S1 through S4 nerve roots are particularly vulnerable, as they exit through foramina that may be disrupted by bony displacement. Compression or laceration of these nerves can lead to radiculopathy, characterized by radiating pain, numbness, and weakness in the legs. More severe cases can result in cauda equina-like syndromes, with saddle anesthesia, bowel or bladder dysfunction, and progressive limb weakness. A review in Spinal Cord (2022) noted that sacral fractures with central canal involvement had a higher likelihood of permanent neurological impairment, particularly when surgical decompression was delayed beyond 48 hours.

Indicators And Symptoms

A sacral fracture often presents with localized pain in the lower back, buttocks, or pelvis, which worsens with movement, prolonged sitting, or weight-bearing activities. Unlike muscular strains, sacral fracture pain is deep and persistent, often intensifying at night or with direct pressure. Patients may also struggle with transitioning from sitting to standing due to pelvic instability.

If the fracture affects the sacral nerve roots, sensory disturbances such as numbness, tingling, or burning sensations may develop in the buttocks, thighs, or perineal region. Motor deficits can emerge, making walking difficult. Some patients experience gait abnormalities due to compensatory postures that help alleviate pressure on the injured area.

Imaging And Diagnostic Techniques

Accurate diagnosis requires clinical evaluation and imaging studies. While physical examination may reveal tenderness and restricted mobility, imaging confirms the fracture type and severity. Standard X-rays are often the first step, but due to the sacrum’s complex anatomy, fractures can be difficult to visualize. A study in The Journal of Trauma and Acute Care Surgery (2021) found that up to 41% of sacral fractures are missed on initial X-rays.

CT scans provide superior detail, offering a three-dimensional view and precise fracture classification. MRI is useful for assessing nerve involvement or detecting insufficiency fractures not visible on CT. Bone scans or DEXA may be used to evaluate osteoporosis, a key risk factor in older adults.

Non-Surgical Interventions

For stable fractures without significant displacement or neurological involvement, conservative management is preferred. Pain control is a priority, with NSAIDs and acetaminophen commonly used. Severe cases may require short-term opioid therapy, though prolonged use is discouraged. Some patients benefit from sacral nerve blocks for temporary relief.

Activity modification is essential to prevent further stress on the healing bone. Patients are typically advised to limit weight-bearing activities, using assistive devices such as walkers or crutches. A study in The Bone & Joint Journal (2022) found that individuals who adhered to partial weight-bearing restrictions for at least six weeks had better healing outcomes. Physical therapy focusing on core stabilization and gentle range-of-motion exercises helps maintain mobility while minimizing strain.

Surgical Procedures

Unstable, significantly displaced, or neurologically involved fractures may require surgery. Percutaneous screw fixation, performed under fluoroscopic guidance, stabilizes the sacrum while preserving surrounding soft tissues. This minimally invasive approach is particularly effective for vertical fractures and reduces recovery time.

More severe cases, such as comminuted fractures or those with extensive sacroiliac joint involvement, may require lumbopelvic fixation. This procedure involves screws and rods to provide structural support. A multicenter study in Spine (2023) found that patients undergoing lumbopelvic fixation had lower rates of nonunion and better long-term functional outcomes. Decompression surgery may be performed if nerve compression is present.

Rehabilitation And Mobilization

Rehabilitation focuses on restoring mobility while minimizing pain and complications. Initially, pain management and protected weight-bearing are emphasized. Patients begin with isometric exercises to maintain muscle strength without stressing the healing bone. Hydrotherapy may be used to allow controlled movement with reduced gravitational load.

As healing progresses, weight-bearing activities increase based on imaging confirmation of fracture consolidation. Strengthening exercises targeting the core, gluteal muscles, and lower extremities help restore stability and prevent compensatory movement patterns. A systematic review in The Journal of Orthopaedic & Sports Physical Therapy (2022) found that balance training and proprioceptive exercises improve functional recovery. Most patients regain near-normal function within three to six months, depending on fracture severity and adherence to rehabilitation protocols.