#s of the hind foot are those involving the calcaneus and the talus.
#s of the talus include #s of the talar neck, the talar body, or the talar head, as well as osteochondral #s and #s of the lateral process.
(Figs. 31-1, 2, 4, and 7.)
# of the talar neck treated with ORIF. After surgery, the patient initially had a bulky compressive dressing. The # was placed in a cast after the edema subsided. Talar #s tend to have less swelling than calcaneal #s.
Mechanism of Injury
#s of the body and neck of the talus usually result from high energy injuries such as motor vehicle accidents.
#s of the head and posterior aspects of the talus usually result from axial load.
Osteochondral #s and lateral process #s are often seen with ankle or subtalar sprains and #/dislocations of the subtalar joint.
Anatomic realignment is more critical for the articular surfaces of the talus than for any other bone in the foot. This is because of the high risk of avascular necrosis due to a poor blood supply.
Stable fixation of talar neck #s is crucial to reduce the risk of avascular necrosis of the talar head. #s of the talar body must be stably fixed to restore subtalar joint congruity. #s of the talar head must be stably maintained to allow for load transfer across the talonavicular joint.
Restore ROM of the ankle and foot in all planes.
Restore the full ROM of the subtalar joint.
Intraarticular #s of the talar body involving the
subtalar joint may have residual loss of ROM. This
causes increased stress on the subtalar articulation
and leads to further degeneration and arthritic
Table 31-1. Ankle Range of Motion dnbid Motion Normal Functional Ankle Plantar Flexion 45 20 Ankle dorsiflexion 20 10 Foot Inversion 35 10 Foot Eversion 25 10
Strengthen the muscles of the foot.
Invertors of the foot
Evertors of the foot
Dorsiflexors of the foot
Plantar flexors of the ankle & foot
Normalize the gait pattern.
EXPECTED TIME OF BONE HEALING
Six to 10 weeks.
EXPECTED DURATION OF REHABILITATION
12 to 16 weeks.
Patients in whom avascular necrosis develops usually need further surgery and extensive rehab for up to 12 months.
Methods of Treatment
ORIF (Multiple Screws)
Biomechanics: stress shielding device with rigid fixation.
Mode of bone healing: Primary, without callus formation.
Indications: Displaced #s of the talus.
(Figs. 31-2, 3, 4, 5, 6, 7, 8, 9 &10).
Biomechanics: Stress sharing device.
Mode of bone healing: Secondary, with callus formation. This mainly cancellous bone shows only a small amount of callous because of the cortex is quite thin and there is minimal periosteum.
Indications: A nondisplaced or minimally displaced # of the talar neck may be anatomically reduced with a closed technique and then placed in a cast.
A problem with this method is that maintaining the patient in a cast precludes the early motion important for successful rehab of the tibiotalar and subtalar joints.
In general , casting as a primary form of treatment should be considered a temporary and not an acceptable final method of treatment.
SPECIAL CONSIDERATIONS OF THE FRACTURE
TENDON & LIGAMENTOUS INJURIES
Because of the large magnitude of the force involved with most of the these #s, there can be significant soft-tissue damage secondary to swelling.
Even with open #s, isolated compartments may still swell and need to be observed .
The patient must be watched carefully for the development of foot compartment syndrome.
#s of talus are initially placed in a bulky compressive dressing or cast with the foot elevated for 2-5 days.
When a walking cast is applied, the patient may be allowed wt-bearing (wt of leg) if the fixation can tolerate it.
It is very important with talar #s for the patient to keep the foot elevated as much as possible in the first 3 weeks to optimize circulation to the talus, in the hope of preventing avascular necrosis (Figs. 31-11 & 12).
In the dependent position, there is inadequate venous return secondary to the vascular congestion caused by the swelling.
Early motion is extremely important for a satisfactory final outcome, and the patient with rigid internal screw fixation frequently is put in a bivalve cast or removable cam walker ( a rigid, padded, supportive splint with a rocker bottom) 2 weeks after surgery to expedite exercise of the joints.
The patient should ideally remain partial wt-bearing for up to 3 months and then progress with wt-bearing as tolerance and radiographic evidence of healing suggest.