Transtibial Amputation

Sarah Kitchin

Erica Patterson

Living Without A Leg

Outline

Statistics on Amputation Transtibial and Transfemoral Differences Fitting Balance Biomechanics Conclusion

Amputation Facts

1,285,000 People Living with Limb Loss in The U.S.• 4.9 per 1,000 people

Of Those 1,285,000 People:• 39,479 were Transtibial Amputations• 36,478 were Transfermoral Amputations (American

Amputee Coalition of America ‘96)

Differences between Transtibial and Transfemoral Amputations Transfemoral Amputations:

• Known as above the knee amputations• Surgeon’s goal is to leave as much residual limb as

possible, preserve the adductor muscles, and the remaining soft tissue. (Biomed, ’03)

Differences between Transtibial and Transfemoral Amputations (Cont.) Transtibial Amputations:

• Known as Below The Knee Amputations

• The Surgeon’s goal is to leave a cylindrical shaped well-padded residual limb.

• Using the gastrocnemius and soleus muscles to create a muscular flap.

• Surgery provides some challenges (In Motion, ’03)

Fitting

An exact mold of the residual limb does not make a good socket

Indent in the region around the patellar tendon Many different types of sockets

• Foam of silicone• Hard• Soft (Smith, ’03)

Study on One Type of Socket

5 Unilateral transtibial amputees Placed in a pressure chamber Produces equally distributed pressure at the

stump/socket interface Comfortable and pressure evenly distributed Still Controversial (Goh, ’03)

Prosthetic Alignment

Alignment is the spatial relationship between the prosthetic socket and foot.

Purpose: Position the prosthetic socket with respect to the foot

so that adverse patterns of force applied to the residual limb are avoided

Produce a normal pattern of gait (Noelle, ’03)

Prosthetic Alignment

(Noelle, ’03)

Prosthetic Alignment Study

Enhance residual limb comfort and maximize walking capabilities in persons with lower extremity amputation

Study suggest prosthetic alignment does promote steady and comfortable walking with a lower extremity prosthesis

Prosthetic misalignment may well lead to instability, discomfort, increased limb loading, and tissue breakdown when applied over a long period of time (Pinzur, ’95).

Balance and Stability Study Significant differences found between TTA and

controls during equilibrium and movement studies. Transition from bipedal to monopedal High failure rate for TTA Same difficulty on sound and prosthetic limb (Viton 00’)

Utilize remaining muscles Work on speed of contraction, not maximal force of

contraction (Gailey 03’)

Walking With a Prosthetic

Prosthetic Walking

Biomechanics - Absorption Phase Reduction in ground reaction force Significant difference in knee angles found at

heel strike. (Isakov 00’) Prosthetic absorbs and generates less

energy which results in A more passive limb Absorption by soft tissue in socket Presence of isometric contraction by muscles So as foot strikes, a backward force is instantly

created by prosthetic-side hip muscles.

(Gailey 02’)

Biomechanics - Deceleration Phase Hip abductors and adductors and knee

extensors muscles are main source of absorption. (Sadeghi 01’)

Fewer gait problems are involved in the swing phase than with the stance.

(Walter 04’)

Biomechanics - Acceleration Phase Hip extensor effort is main compensation of

propulsion reduction. (Pailler 04’) Amputation of ankle reduces the ability of

power to be produced through plantar flexion.

(Sadeghi 01’)

Biomechanics Summary

Longer motions for amputated side Step length Step time Swing time

Shorter motions for amputated side Stance time Single support time

(Isakov 00’)

Energy Cost Studies

Energy cost depends on Gait speed Efficiency Not on displacement of center of mass (Detrembleur 05’)

Energy consumption For transfemoral amputees is more significant than that of

transtibial amputees. Is affected by prosthetic alignment Is not affected by the use of different prosthetic feet

(Schmalz 02’)

Energy Expenditure for Amputation

Amputation Level

Energy Above Baseline, %

Speed, m/min Oxygen Cost, ml/kg/m

Long Transtibial 10 70 .17

Average Transtibial

25 60 .20

Short Transtibial

40 50 .20

Bilateral Transtibial

41 50 .20

Transfemoral 65 40 .28

Wheelchair 0-8 70 .16

(Janos 05’)

Summary

Transtibial amputations are more common then transfemoral amputations. There is not one best type of socket fitting Balance and stability has same difficulty whether

on sound or prosthetic limb Biomechanics are compensated by use of

muscles and the combination of longer and shorter motions using amputated side.

Energy costs depend on gait speed and efficiency, not displacement of center of mass

References

Amputation and Limb Deficiency. <http://biomed.edu/Courses/BI108/BI108_2003_Groups/Athletic_Prosthetics/Bkgd>. 14 November 2005.

Amputee Coalition of America. <http://www.amputee-coalition.org/index.html>. 28 November 2005. Goh, J.C.H., Lee, P.V.S, Chong, S.Y. “Stump/Socket Pressure Profiles cast prosethetic socket.”

Clinical Biomechanics. 18 (2003): 237-244. Detrembleur, Christine. “Relationship Between Energy Cost, Gait Speed, Vertical Displacement of

Centre of Body Mass and Efficiency of Pendulum-Like Mechanism in Unilateral Amputee Gait.” Gait & Posture. 21 (2005): 333-340.

Gailey, Robert. “The Biomechanics of Amputee Running.” The O&P Edge. www.oandp.com/edge October 2002.

Gailey, Robert. “Stability Within the Socket Creates Stable World.” The O&P Edge. www.oandp.com/edge September 2003.

Information about Transtibial Prosthetics. <http://www.nupoc.northwester.edu/prosBK.shtml>. 28 November 2005.

Isakov, E. “Trans-tibial Amputee Gait: Time-distance Parameters and EMG Activity.” Prosthetics and Orthotics International. 24 (2000): 216-220.

Janos, Ertl P. “Amputations of the Lower Extremity.” eMedicine http://www.emedicine.com/orthoped January 2005.

Miller, William C. “Balance Confidence Among People With Lower-Limb Amputations.” Journal of the American Physical Therapy Association. (2002).

References (Cont.)

Nadollek, Heidi. “Outcomes After Trans-Tibial Amputation: The Relationship Between Quiet Stance Ability, Strength of Hip Abductor Muscles and Gait.” Physiotherapy Research International. 7 (2002): 203-214.

Noelle, Lannon. “Trans-tibial Alignment: Normal Bench Alignment.” Ortholetter: International society for Prosthetics and Orthotics. <http://home.ica.net/~cocinc/Alignment.html>. July 2003.

Nolan, L. “The Functional Demands On the Intact Limb During Walking for Active Trans-Femoral and Trans-Tibial Amputees.” Prosthetics and Orthotics International. 24 (2000): 117-125.

Pailler, D. “Evolution in Prostheses for Sprinters With Lower-Limb Amputation.” Annales de Readaptation et de Medecine Physique. 47 (2004): 374-381.

Pinzur, Michael S., Cox, William. “The Effect of Prosthetic Alignment on Relative Loading in Person With Trans-tibial Amputation: A Preliminary Report.” Journal of Rehabilitation Research & Development. 32 (1995): 373-378.

Sadeghi, H. “Muscle Power Compensatory Mechanisms In Below-Knee Amputee Gait.” American Journal of Physical Medicine & Rehabilitation. 80 (2001): 25-32.

Shmalz, Thomas. “Energy Expenditure and Biomechanical Characteristics of Lower Limb Amputee Gait: The Influence of Prosthetic Alignment and Different Prosthetic Components.” Gait & Posture. 16 (2002): 255-263.

Smith, Douglas G. M.D. “Transtibial Amputations: Successes and Challenges.” Notes from the Medical Director.

Viton, J M. “Equilibrium and Movement Control Strategies in Trans-Tibial Amputees.” Prosthetics and Orthotics International. 24 (2000): 108-116.

Walter, Ellis. “Gait Analysis After Amputation.” eMedicine. http://www.emedicine.com/orthoped April 2004.