Transtibial prosthesis

An alternative means of suspension that has become increasingly common for transtibial amputees is suctiorL Suction has b n used routinely for individuals wiA transfemoral amputation fin-some time. Its use in transtibial prostheses has increased through the use of a shutde locking pin, such as incorporated in the Silcone Suction Socket (3S, Durr-Fillauer, Chattanooga, Term.) (Fig. 33.11). 

While transtibial prostheses may be worn without an insert, such practice is less common. Silicone or foam (e.g., Pelite, Spenco, Plastazote) inserts are often used to cushion the residual limb and potentially absorb and redistribute some of the compressive and shear forces generated during ambulation. In addition, the transtibial amputee typically wears cotton, wool, or synthetic socks, 1 to 15 ply, to absorb or wick perspiration and accommodate residual limb volume fluctuations often observed throughout the day. 

Transtibial prosthesis Artificial leg for amputees with the amputation between the ankle and the knee joints (transtibia)... 

FIGURE 33.6 PreparaloiY transtibial prosthesis. (Adapted from R. 49, Fig. 3.4.)... 

The transtibial prosthesis incorporates one of the aforementioned prosthetic socket designs and suspension methods, a spacer (shank), and an artificial foot. The transfemoral prosthesis is similar, with the inclusion of a prosthetic knee unit and an additional spacer for the thigh. The spacer is usually made of wood, plastic, or metal depending on whether the design is exo- or endoskeletal. 

Keywords— Transtibial prosthesis. Suspension, Pistoning, Weight bearing, liner. 

Narita H, Yokogushi K, Shi S et al. (1997) Suspension effect and dynamic evaluation of the total surface bearing (TSB) trans-tibial prosthesis a comparison with the patellar tendon bearing (PTB) transtibial prosthesis. Prosthet Orthot Int 21(3) 175-178... 

Tanner J, Berke G (2001) Radiographic comparison of vertical tibial translation using two types of suspensions on a transtibial prosthesis a case study. JPO 13(1) 14... 

Since the design of the prosthesis varies with amputation level, prosthetic design will be reviewed for the aforementioned lower extremity amputation levels. Since the primary levels of lower extremity amputation are transtibial (54 percent") and transfemoral (33 percent"), the prostheses for these amputation levels will be presented in greater detail. 

Transtibial (Below-Knee) Amputation Prostheses. By definition, the residual limb of a functional transtibial amputee includes tibial tubercle into which the quadriceps tendon inserts so as to retain knee extension capability. The prosthesis for a transtibial amputee, in general, consists of a socket with an optional insert, adapter hardware to attach the socket to the shank, and an artificial foot. In addition, the prosthesis often includes some means of auxiliary suspension. 

The residual limb-prosthetic socket stresses are influenced by the fit of the socket and the alignment of the prosthesis. For transdbial amputees, medial-lateral stability is influenced by foot placement. Foot inset (or outset) may result in varas (or valgus) moments applied to the limb. Similarly, anterior-posterior stability is influenced by the fore-aft position (extension-flexion moment) of the foot, foot plantarflexion/dorsiflexion (extension-flexion moment), and heel durometer (soft heel increases foot plantarflexion). For transtibial amputees with normal knee extensors, knee flexion moments on heel strike are desired, as for individuals without amputation. 

Sodeiberg B, L Ryd, B Persson. (2003) Roentgen stereophotogrammetric analysis of motion between the bone and the socket in a transtibial amputation prosthesis a case study. J Prosfliet Orthot 15(3) 95-99. 

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