Forefoot rockers in all AFOs may be easily blocked. The children described here compensated for the blocked rocker by internally rotating the legs, walking in equinus, and falling. Internal rotation of the hips is a very complicated subject. Orthoses that block the forefoot rocker are not listed as a cause for internal hip rotation.26 Recommendations in the literature report that the best, if not the only, way internal rotation can be corrected is with surgery.27 However, O'Sullivan et al28 caution that since it is difficult to identify the cause of internal rotation, the treatment is often unclear and outcomes are unpredictable and sometimes unsatisfactory. The findings from these cases suggest that bilateral orthoses should be listed as another cause of internal hip rotation. If only one side is blocked, that leg often externally rotates and the child does not shift weight adequately to that side. The leg is used more as a “peg leg.”
Both children described in cases 1 and 2 received new SMOs with free plantar flexion but with blocked forefoot rockers. Although both children were classified at GMFCS Level II, the child in case 2 had spastic quadriplegia and more motor involvement, which could explain why she also had loss of balance when the forefoot rocker was blocked. Figure 3B shows the child described in case 2 walking flat-footed with forefoot rocker unblocked without hand support and with her arms lowered. The child described in case 1 had spastic diplegia and more muscle control and so his compensation allowed him to enjoy bouncing on his toes without falling. He also compensated with slight internal hip rotation before the SMOs were corrected. Both children had immediate positive changes in gait when small pieces of plastic trim, which blocked digit extension, were removed. The orthoses of the child described in case 3 had a large amount of plastic over the toes for which he compensated with internal hip rotation until the blockage was removed. For the children in cases 1 and 2, plantar flexion was available and they each had enough strength to walk on their toes and maintain the PF/KE couple. The child in case 3 did not have plantar flexion available and needed to rotate the leg, reduce the PF/KE couple, and shorten the foot lever length.
Both children in cases 1 and 2 responded to the blocked forefoot rocker with excessive knee and ankle extension after mid-stance. This excessive knee extension and plantar flexion seems similar to the concern that Buckon and colleagues12 expressed in their 2004 study of children with spastic diplegia walking barefoot or wearing various orthoses. They reported that some children with spastic diplegia at GMFCS Level II had an increase in knee extension in early stance. It appears that those in GMFCS Level I did not have this problem, perhaps because they were more developed than those at Level II. Buckon and colleagues12 felt that the excessive knee extension was detrimental for those at Level II because of the mobile ankle joint and they reversed their previous recommendation of using the HAFO over the SAFO. They concluded that one should constrain ankle movement in some children who walked on their toes. However, all their AFOs had the forefoot rocker blocked with extended trim lines and this blockage may have caused the excessive knee extension rather than the ankle hinge. These compensations over time may have become permanent and may not have been a result of the initial brain lesion but a result of the orthoses.
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