Inversion, ankle

Prosthetic Feet. With the exception of partial foot amputees, the prostheses for all lower extremity amputees require a prosthetic foot. The prescription criteria for these feet take into consideration the amputation level, residual limb length, subject activity level, cosmetic needs, and the weight of the individual. Prosthetic feet range from the SACK (solid ankle cushioned heel) foot, which is relatively simple and inexpensive, to dynamic-response or energy-storing feet that are more complicated and considerably more costly. Note that prosthetic feet are often foot and ankle complexes. As such, prosthetic feet may replace plantarflexion/dorsiflexion, pronation/supination, and inversion/eversion. Prosthetic feet are typically categorized in terms of the function(s) they provide or replace and whether or not they are articulated. 

Nonarticulated feet are typically the simplest and least expensive. The foot and ankle are combined in a single component, and shock absoiption and ankle motion are provided by the materials and structure of the foot. Since these feet are nonarticulated, diey are quiet and typically require little maintenance. These feet are also cosmetic, lightweight, and provide good shock absorption and limited inversion/eversion on uneven terrain. Disadvantages of nonarticulated feet are the limited range of plantarflexion/dorsiflexion, difficulty with inclines due to heel compression, lack of adjustability for different heel heights, and little torque-absorption capability. 

These are usually Salter-Harris Type I or II fractures caused by a supination-inversion injury. They may not be evident on plain X-ray and are often incorrectiy diagnosed as an ankle sprain. Ultrasound is very accurate in detecting the cortical discontinuity, periosteal elevation and subperiosteal fluid which accompanies these fractures (Simanovsky et aL 2005). Where these injuries occur in isolation they should be managed in a below-knee walking cast for 3 to 4 weeks. Significantly displaced distal fibular fractures associated with Salter-Harris Type III or IV injuries usually reduce with re-... 

In the talus the terms osteochondral fracture, tran-schondral fracture and osteochondritis dissecans are used interchangeably. The condition is usually seen in adolescence. An associated history of trauma is identified in 64%-92% of patients (Berndt and Harty 1959 Ogilvie-Harris and Sarrosa 1999 Stone 1996) and tends to be an inversion type injury. Lateral lesions are said to be more commonly associated with trauma than medial lesions. The initial complaint is of ankle pain, swelling and a limp. Symptoms of instability and locking or clicking within the joint may also be described. 

A thorough history, physical examination, and ancillary studies should be performed before treatment is instituted. The ankle joint is commonly involved in eversion and inversion strains or sprains, as well as in malleolar fractures. Dysfunction often follows immobilization treatment procedures. People with healed fractures may still have unresolved somatic dysfunctions. 

FIG. 100-4 High-velocity, low-amplitude thrusting technique for an eversion-inversion ankle somatic dysfunction. 

A diagnosis of an acute Inversion sprain-strain of the right ankle was made. The degree of the strain was not Identified until the swelling re-... 

In the anterior ankle, four extensor tendons lie alongside each other. From medial to lateral, these are the tibialis anterior, the extensor hallucis longus, the extensor digitorum longus and the peroneus ter-tius tendons (Fig. 16.4). The tibialis anterior is the largest and the most medial tendon. During dorsi-flexion and inversion of the ankle, it can easily be... 

The motions of the ankle can be described in three orthogonal axes, which include axial rotation (intemal/extemal) in the transverse plane, inversion/eversion in the frontal plane, and dorsiflexion/plantarflexion in the sagittal plane (Figure 11.3). Motion along all three axes is pronation/ supination, where pronation is dorsiflexion, eversion and external rotation and supination is plantarflexion, inversion. 

FIGURE 11.3 Motions of the ankle in the sagittal plane (top from left to right neutral, dorsiflexion, plantarflexion), frontal plane (middle from left to right neutral, eversion, inversion), and transverse plane (bottom from left to right neutral, external rotation, internal rotation). 

The Newton ankle prosthesis (designed in 1973) was a two-part, nonconstrained prosthesis that had a UHMWPE tibial component with a flat proximal surface and a curved, cylindrical articulating surface [26, 27] (Figure 11.7). It has been described as a multiaxial joint that allows unrestricted motion about any of the three major axes [19]. The talar component comprised CoCr alloy and had a spherical articulating surface with a distal stem that was implanted into the talus. The result was an incongruent articulating surface that allowed dorsiflexion/plantarflexion, as well as slight inversion, eversion, and rotation [26, 27]. 

Cadaver studies have demonstrated changes in ankle biomechanics in normal ankles versus those implanted with STAR devices [69]. There were no significant differences in inversion/eversion. Dorsiflexion and plantarflexion were significantly reduced in STAR ankles. Significant increases in range of motion were observed during internal tibial rotation, while significant decreases in exterior tibial rotation were observed in the STAR ankles [69]. 

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