TY - JOUR
T1 - The effect of ankle injury on subtalar motion
AU - Michelson, James
AU - Hamel, Andrew
AU - Buczek, Frank
AU - Sharkey, Neil
PY - 2004/9
Y1 - 2004/9
N2 - Background: Injuries to the medial and lateral ankle ligaments have been implicated in subtalar joint instability. Lateral injury increased subtalar joint varus and anterior translation, while deltoid injury increased external rotation and valgus in studies using static, non-physiologic testing. Methods: The current study employed a physiologically accurate ankle model using phasic force-couples attached to the muscle-tendon units to reproduce ankle motion. Six-degree-of-freedom kinematics of the tibia, talus, and calcaneus were measured using a VICON motion analysis system under the following experimental conditions: 1) intact ligaments 2) complete lateral ligament injury with subsequent repair, 3) superficial deltoid injury with subsequent repair, and 4) deep deltoid injury without repair in eight harvested lower extremities. Statistical analysis was by repeated measures analyses of variance. Results: At heel-strike, the subtalar joint is in internal rotation, dorsiflexion, and varus. As the leg progresses to foot-flat, there is external rotation, plantarflexion, and valgus rotation. From foot-flat to heel-rise, there is little subtalar joint motion, while at toe-off, there is slight internal rotation, dorsiflexion, and varus rotation. The total rotations amounted to 9.0 degrees (SD 5.0 degrees) external rotation, 6.1 degrees (SD 2.5 degrees) plantarflexion, and 7.8 degrees (SD 5.5 degrees) valgus. Disruption of the superficial deltoid increased plantarflexion (p < .001) and valgus (p < .05). The additional lateral injury increased both external rotation (p < .001) and valgus (p < .02). Lateral injury alone had no significant effect on subtalar joint motion. Conclusion: Unlike most previous reports, this study showed no significant influence of isolated lateral ankle injury on subtalar joint motion, probably because the current study examined subtalar joint motion under physiologic loading and motion rather than by static stress testing. This calls into question the relevance of static stress testing to the in situ function of the subtalar joint. The increased external rotation and valgus seen with deltoid injury in the current study is consistent with previous reports.
AB - Background: Injuries to the medial and lateral ankle ligaments have been implicated in subtalar joint instability. Lateral injury increased subtalar joint varus and anterior translation, while deltoid injury increased external rotation and valgus in studies using static, non-physiologic testing. Methods: The current study employed a physiologically accurate ankle model using phasic force-couples attached to the muscle-tendon units to reproduce ankle motion. Six-degree-of-freedom kinematics of the tibia, talus, and calcaneus were measured using a VICON motion analysis system under the following experimental conditions: 1) intact ligaments 2) complete lateral ligament injury with subsequent repair, 3) superficial deltoid injury with subsequent repair, and 4) deep deltoid injury without repair in eight harvested lower extremities. Statistical analysis was by repeated measures analyses of variance. Results: At heel-strike, the subtalar joint is in internal rotation, dorsiflexion, and varus. As the leg progresses to foot-flat, there is external rotation, plantarflexion, and valgus rotation. From foot-flat to heel-rise, there is little subtalar joint motion, while at toe-off, there is slight internal rotation, dorsiflexion, and varus rotation. The total rotations amounted to 9.0 degrees (SD 5.0 degrees) external rotation, 6.1 degrees (SD 2.5 degrees) plantarflexion, and 7.8 degrees (SD 5.5 degrees) valgus. Disruption of the superficial deltoid increased plantarflexion (p < .001) and valgus (p < .05). The additional lateral injury increased both external rotation (p < .001) and valgus (p < .02). Lateral injury alone had no significant effect on subtalar joint motion. Conclusion: Unlike most previous reports, this study showed no significant influence of isolated lateral ankle injury on subtalar joint motion, probably because the current study examined subtalar joint motion under physiologic loading and motion rather than by static stress testing. This calls into question the relevance of static stress testing to the in situ function of the subtalar joint. The increased external rotation and valgus seen with deltoid injury in the current study is consistent with previous reports.
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U2 - 10.1177/107110070402500908
DO - 10.1177/107110070402500908
M3 - Article
C2 - 15563386
AN - SCOPUS:4544387733
SN - 1071-1007
VL - 25
SP - 639
EP - 646
JO - Foot and Ankle International
JF - Foot and Ankle International
IS - 9
ER -