6.6 Limited Mobility & Spinal Cord Injury
Key Takeaways
Adapt transfer and positioning to the individual, and record limits that affect interpretation.
For adults with spinal cord injury and permanent motor or sensory dysfunction, ISCD recommends assessment at total hip, distal femur and proximal tibia as soon as medically stable.
Use comparable dedicated scans for treatment monitoring. Whole-body subregions do not substitute for dedicated SCI monitoring sites.
Review BMD together with clinical risk when considering weight-bearing activity in SCI.
Start with the reason for limited mobility
Reduced loading can accelerate bone loss. A patient with a cast, a prolonged hospital stay, stroke-related weakness or a spinal cord injury (SCI) may also have difficulty transferring or holding a standard position. Ask about the affected limb, duration of reduced loading, recent fracture, hardware and whether the patient can safely move to the table. Prolonged immobilization is one setting in which the International Society for Clinical Densitometry (ISCD) allows a shorter testing interval when clinically appropriate. Adapt positioning and document limitations. The cause of reduced mobility helps determine which acquisition protocol is appropriate.
Use the SCI-specific sites when indicated
SCI with permanent motor or sensory dysfunction has a distinct adult pathway. Fractures after SCI frequently occur near the knee, especially at the distal femur and proximal tibia. ISCD recommends an initial dual-energy X-ray absorptiometry (DXA) assessment of the total hip, distal femur and proximal tibia once the adult is medically stable. Those sites can support osteoporosis assessment, lower-extremity fracture risk evaluation and monitoring when suitable normative data are available. The standard PA lumbar spine examination alone does not assess the sites emphasized in this pathway.
| Situation | How to proceed |
|---|---|
| First assessment after adult SCI with permanent dysfunction | Plan safe transfer and positioning with the patient and the care team. Obtain dedicated scans of the total hip and knee regions under an appropriate protocol when feasible. |
| Contracture, spasm, hardware or prior fracture limits a region | Use safe positioning and review the image and ROI. Document the side, support and limitation. If necessary, seek a center with an SCI protocol or use the valid available measurements within their scope. |
| No validated reference or usable ROI for a knee result | Report limitations. A knee score derived from an unrelated database cannot supply a diagnosis. Do not apply the usual WHO hip threshold to an arbitrary knee T-score. |
| Planning rehabilitation | ISCD identifies no established BMD value below which weight-bearing activity is absolutely contraindicated. Evaluate BMD and other clinical factors with the rehabilitation team. |
In other causes of limited mobility, use the appropriate standard sites and alternatives based on what can be measured safely and validly. An adult with a temporary cast does not automatically need the SCI-specific regions. If a standard hip or spine cannot be measured or interpreted, an indicated forearm result may help answer the diagnostic question under the general adult positions.
Monitor with a dedicated comparable study
For assessing therapy after SCI, the ISCD position specifies the total hip, distal femur and proximal tibia after at least 12 months of therapy, at one- to two-year intervals. This addresses assessment of treatment effectiveness. It is not the timing rule for the initial scan. Do not use a whole-body DXA image's segmental knee regions for treatment monitoring. A dedicated knee protocol uses defined landmarks, positioning and ROI analysis. Keep the side, reference and analysis method consistent. Apply the applicable site-specific precision and LSC rather than borrowing a hip or spine threshold for the knee.
Worked comparison
An adult with chronic SCI has valid dedicated distal femur measurements of 0.480 and 0.449 g/cm² after 18 months of treatment. The facility provides an illustrative distal femur LSC of 0.026 g/cm² for the same side and protocol. The decrease is 0.031 g/cm², or about 6.5% of baseline, which meets the significance criterion if the studies are comparable. Check motion, landmark matching and technical quality before reporting. Do not conclude from the change alone that the medication caused the loss. Review the result alongside the rest of the clinical assessment.
If the only earlier value had been extracted from a whole-body scan, the two numbers would not support that quantitative treatment comparison. Use the new dedicated scan as a suitable reference when appropriate. If a patient has pain, swelling or a suspected new fracture, communicate with the clinical team about diagnostic evaluation. A follow-up densitometry measurement serves a different purpose from assessing a possible acute injury.
ISCD Adult Official Positions · Original SCI position paper · PVA SCI clinical guideline · Primary knee DXA precision study
A medically stable adult has a spinal cord injury that caused permanent motor dysfunction. Which DXA sites should be assessed under the ISCD SCI position?
Only PA lumbar spine.
Distal radius and lumbar spine only.
Femoral neck and Ward’s area only.
Total hip, distal femur and proximal tibia.
An adult with SCI has received treatment for 18 months. The prior knee value came from a segment of a whole-body scan. What can be done with the current valid dedicated distal femur scan?
Use it as a dedicated reference and explain why the whole-body segment is unsuitable for a quantitative therapy comparison.
Compare the two values directly after applying the spine LSC.
Convert the whole-body value to a hip T-score and monitor it.
Discard the dedicated result because the assessment must be delayed until exactly two years.
How should an SCI rehabilitation team use a low knee BMD result before planning weight-bearing activities?
Prohibit weight bearing at a universal knee T-score below −2.5.
Ignore the result because BMD has no relevance to fracture risk.
Consider BMD along with the patient’s other clinical risk factors. There is no established absolute BMD cutoff.
Apply a wrist BMD cutoff to determine safety.
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