Prosthetic Gait Deviations

1. Prosthetic Gait Deviations Karyn Duff Prosthetist / Orthotist Hunter Prosthetics and Orthotics Service

2. What is a gait deviation? • Any gait characteristic that differs from the normal pattern • Unsymmetrical gait • Many possible causes: • Prosthetic • Reduced ROM • Muscle weakness • Fear / Insecurity • Habit

3. Prosthetic Alignment • Correct alignment of the prosthesis allows: • Optimal gait • Optimal pressure distribution across stump • Optimal stability • Optimal control • Reduces energy expenditure • Three steps to prosthetic alignment • Bench alignment • Static alignment • Dynamic alignment

4. Bench alignment – Trans tibial Sagittal Plane • Heel height matches patient’s shoe • Socket 5° flexed • Weight line • Centre of lateral socket • Posterior 1/3 of foot

5. Bench alignment – Trans tibial Frontal Plane • Abduction / Adduction to match patient • Weight line • Centre of posterior socket • Centre of heel (or up to 10mm laterally) Transverse Plane • 5-10° toe out

6. Bench alignment – Trans femoral • Heel height matches patient’s shoe • Socket 5° flexed • Weight line • Centre of lateral socket • 5-15mm anterior to knee centre • Posterior 1/3 or foot • Length may be up to 10mm shorter than sound side

7. Common Prosthetic Gait Deviations

8. Rotation of prosthetic foot at IC • Description • Prosthetic foot externally rotates at Initial Contact • Causes • Too hard a heel • Too hard a plantarflexion bumper • Socket too loose

9. Foot slap • Description • Foot progresses too quickly from heel strike to foot flat, creating a slapping noise • Causes • Heel too soft • Plantarflexion bumper too soft • Excessive socket flexion • Excessive dorsiflexion • Poor knee extension control

10. Excessive knee flexion (at IC) • Description • Knee flexes excessively at I.C • Patient feels like he’s walking downhill • Causes • Heel cushion too hard • Excessive dorsiflexion of prosthetic foot • Foot too posterior in relation to socket • Excessive flexion built into socket

11. Lateral Trunk Bending • Description • Trunk bends towards amputated side during prosthetic stance phase • Causes • Short prosthesis • Pain on lateral distal aspect of stump • Abducted socket • Low lateral wall of socket • Weak hip abductors • Short stump

12. Medio-lateral knee thrust • Description • Knee shifts medially or laterally during prosthetic stance phase • Causes • Foot placed too medially (lateral thrust) • Foot placed too laterally (medial thrust) • ML dimension of proximal socket too large

13. Abducted gait • Description • Walking base significantly larger than normal range of 50-100mm • Causes • Prosthesis too long • Too small socket • Insufficient suspension • Locked knee • Abducted socket • Pain in groin area • Fear / Insecurity • Contracted hip abductors

14. Absent or insufficient knee flexion • Description • Insufficient knee flexion at I.C and / or knee hyperextension at T.S • Patient may report pressure on distal tibia • Patient feels like he’s walking uphill • Causes • Excessive plantarflexion of prosthetic foot • Heel too soft • Too soft a plantarflexion bumper • Insufficient socket flexion • Foot too anterior in relation to socket

15. Circumduction • Description • Prosthesis follows a lateral curved line as it swings through • Causes • Prosthesis too long • Locked knee • Inadequate suspension • Too small a socket • Foot set in plantarflexion • Lack of knee flexion (fear / insecurity of patient)

16. Vaulting • Description • Amputee bobs up and down excessively as he walks. He raises his entire body by plantar-flexing the sound foot. • Causes • Prosthesis too long • Inadequate suspension • Locked knee • Socket too small • Foot set in plantarflexion • Lack of knee flexion (fear / insecurity of patient)

17. Uneven Timing • Description • Steps are of uneven duration or length, usually a short stance phase on the prosthetic side • Causes • Poorly fitting socket causing pain • Fear / insecurity • Poor balance • Weak stump musculature

18. Instability of prosthetic knee • Description • The prosthetic knee has a tendency to buckle on weight bearing • Causes • Incorrect alignment of prosthesis (weight line passes behind knee centre creating flexion moment) • Weak hip extensor muscles • Severe hip flexion contracture

19. Terminal swing impact • Description • The prosthetic shank comes to a sudden stop with a visible or audible impact • Causes • Insufficient knee friction • Extension assist too great • Habit of forceful knee flexion • Fear of knee buckling at I.C

20. Increased Lumbar Lordosis • Description • Lumbar lordosis is exaggerated during prosthetic stance phase • Causes • Insufficient AP socket support • Insufficient socket flexion • Pain on ischial tuberosity area • Hip flexion contracture • Weak hip extensors or abdominals

21. Swing Phase Whips • Description • At toe off heel moves laterally (lateral whip) or medially (medial whip) • Causes • Inadequate suspension • Knee internally rotated (lateral whip) • Knee externally rotated (medial whip)

22. Uneven heel rise • Description • Prosthetic heel rise does not match sound side. • Causes • Inadequate knee friction (high heel rise) • Inadequate extension assist (high heel raise)

23. Excessive forward flexion • Description • During stance patient excessively leans forward • Causes • Unstable knee joint • Hip flexion contracture • Too short gait aids

24. Any Questions???