When Surgical Correction Restores Foot Alignment but Not Walking: A Spina Bifida Clinical Reflection
A recent clinical encounter reminded me of an important rehabilitation principle: correcting the shape of a foot and restoring functional walking are related goals, but they are not the same outcome.
The person had spina bifida and had previously been able to walk, although the left foot was markedly deformed. Corrective surgery brought the foot into a straighter position and internal fixation was used to maintain the correction. After surgery, however, the person could no longer accept weight confidently through that limb. Walking required a walker, and the left knee buckled whenever weight was transferred onto it. An AFO was already being used on the opposite limb.
This reflection has been deliberately de-identified. It does not include the patient’s name, age, photograph, hospital, surgical date or other identifying information. The banner is an educational illustration, not the patient.
The Initial Question: Did the Rod Stop Weight-Bearing?
It is understandable to associate the loss of walking with the internal fixation because the change occurred after surgery. The fixation itself, however, was probably intended to hold corrected bones or joints in the required position while healing or fusion occurred. Its presence does not automatically explain long-term inability to bear weight.
The first distinction is whether weight-bearing is still medically restricted or whether the surgeon has permitted loading but the person cannot control the limb. A non-weight-bearing or partial-weight-bearing instruction protects healing tissue and must never be overridden by an orthotic trial. If healing is complete and full loading is permitted, the assessment moves from surgical protection to neuromuscular and biomechanical control.
Spina Bifida Changes the Clinical Picture
Lower-limb deformities in spina bifida commonly develop from paralysis, reduced sensation and muscle imbalance. Surgery can improve alignment, create a more plantigrade foot and facilitate footwear or bracing, but it does not repair the underlying neurological lesion. Muscle power, protective sensation, joint control and balance may remain limited after a technically successful correction.
The opposite-side AFO is a particularly important finding. It suggests that this is not simply an isolated left-foot problem. Both limbs may be affected by neurological weakness, although the pattern and severity can differ. The opposite limb may therefore be unable to compensate adequately when the operated limb cannot accept weight.
The Key Finding: Stance-Phase Knee Buckling
When asked what happened during weight-bearing, the person described the left knee buckling and an inability to control it. This immediately shifted the clinical focus from the foot alone to the entire lower-limb kinetic chain.
During early stance, the limb must control hip, knee and ankle flexion while supporting body weight. Weak quadriceps may be unable to prevent the knee from collapsing into flexion. Weak hip extensors, poor trunk control, altered ankle position and an unfavorable ground-reaction force can increase the demand further.
Surgical correction created a straighter left foot, but the altered alignment may have exposed inadequate knee-extensor control. This results in stance-phase knee buckling, loss of functional weight acceptance and increased dependence on the walker.
How a Deformed Foot May Have Functioned as Compensation
Before surgery, the deformed foot was not anatomically ideal, but it may have created a familiar base of support or positioned the ground-reaction force in a way that helped stabilize the knee. The person had learned to use that alignment over time.
After correction, the foot became straighter, but the relationship between the floor, ankle, knee and hip changed. If the corrected foot allows uncontrolled tibial progression, the ground-reaction force may pass behind the knee and create an external knee-flexion moment. A weak quadriceps then cannot resist the resulting buckling.
This does not mean the surgical correction was wrong. It means that postoperative rehabilitation and orthotic planning must account for the new biomechanics rather than expecting the previous walking strategy to continue unchanged.
A Whole-Limb Assessment Is Required
Before selecting an orthosis, I would want to document:
- The exact surgical procedure, fixation location and current radiographic healing
- The surgeon’s weight-bearing clearance
- Manual muscle testing of hip extensors, hip abductors, quadriceps, hamstrings and ankle muscles
- Passive hip, knee and ankle range, including knee-flexion contracture
- Whether the foot or ankle has been fused and how much motion remains
- Foot alignment inside appropriate footwear
- Protective sensation, skin condition, swelling and circulation
- Pelvic and trunk control during standing
- The design and purpose of the AFO on the opposite limb
- Knee behaviour during weight shifting, parallel-bar standing and walker-assisted gait
Could an AFO Control the Knee?
An AFO changes more than ankle motion. By controlling the position and progression of the tibia, it can influence the external moment acting at the knee. A properly aligned ground-reaction AFO may shift the ground-reaction force anterior to the knee and reduce excessive stance-phase knee flexion in a suitable patient.
However, a GRAFO is not an automatic answer to every buckling knee. It is less likely to succeed when there is a substantial fixed knee-flexion contracture, severe hip weakness, marked coronal instability, poor tolerance of pressure or insufficient control despite optimal ankle alignment.
When Direct Knee Control May Be Necessary
| Orthotic level | Potential role | Important limitations |
|---|---|---|
| Solid AFO or GRAFO | Controls ankle and tibial progression to influence knee stability indirectly | Requires suitable range, alignment and sufficient proximal control |
| Locked-knee KAFO | Prevents knee flexion during stance and provides dependable stability | Increases energy demand and makes sitting and swing-phase clearance more difficult |
| Stance-control KAFO | Resists or locks knee flexion in stance while permitting flexion during swing | Requires careful patient selection, training, maintenance and adequate hip control |
If the knee continues to buckle during an appropriately aligned AFO trial, or if quadriceps control is insufficient for safe stance, a KAFO assessment may be required. Because the opposite limb already uses an AFO, the additional weight and energy cost of a KAFO must be considered carefully.
A Practical Trial Sequence
- Confirm medical clearance: Obtain the operative information, imaging and permitted weight-bearing status.
- Establish baseline control: Assess supported standing, weight shifting and knee behaviour in parallel bars.
- Test ankle-level influence: Use temporary rigid control or a trial GRAFO alignment to determine whether controlling tibial progression stabilizes the knee.
- Test direct knee stabilization: If buckling persists, compare manual knee control or a trial KAFO.
- Evaluate both limbs together: Review the opposite AFO, leg-length relationship, footwear and walker height.
- Train the new strategy: Coordinate orthotic fitting with physiotherapy for weight acceptance, balance and gait training.
- Protect the insensate limb: Introduce wear gradually and perform frequent skin inspection.
A corrective orthosis should not be prescribed from the description alone. Loading must be cleared by the surgeon, and persistent inability to bear weight requires evaluation for non-union, malalignment, hardware problems, infection, skin injury, pain and neurological deterioration—including possible tethered cord where clinically suspected.
What This Case Teaches
A plantigrade foot is valuable, but it is only one part of walking. Functional mobility depends on the combined performance of the foot, ankle, knee, hip, trunk, sensation, balance, assistive device and the person’s confidence.
For me, the central lesson is that postoperative orthotic assessment should begin before assuming that a straighter foot will automatically produce better gait. The clinician must ask what compensation existed before surgery, what changed mechanically afterward and where stability is now being lost.
This is where orthotics can act as the bridge between structural correction and functional rehabilitation—but only when the complete person, both lower limbs and the entire gait pattern are assessed.
This post is for professional education and does not provide a diagnosis or individual prescription. Clinical decisions require the surgical report, imaging, physical examination and multidisciplinary assessment.
Clinical references: Orthopaedic management of spina bifida—foot and ankle deformities; Mobility guidelines for people with spina bifida; Orthopedic guidelines for people with spina bifida.