The Effect of Targeting the Plantaris Muscle-tendon Unit in Surgical Correction of Ankle Equinus in Children
Tight ankle muscles can produce ankle equinus (limited ability to pull the foot upward) and occur often in children, significantly impacting their ability to walk. If not treated, children with ankle equinus frequently experience reduced function and long-term foot problems, such as pain. Currently, treatment options include surgery or Botulinum toxin (BoNTA) injection into the large calf muscles that point the foot downwards, aiming to reduce their tightness. However, these treatments can be less effective over time, can create prolonged calf weakness, and may require long-term bracing. Another small muscle in the leg, the plantaris, is believed to have some contribution to equinus in many children. It is sometimes included in treatment plans for equinus but its contribution is poorly understood. It is unclear whether targeting the plantaris alone could lead to better treatment of ankle equinus. Understanding the effect of treatments targeting the plantaris could help clinicians improve the management of ankle equinus. In this study, we will look at the impact of surgical treatment to the plantaris in ankle equinus. We hypothesize that the plantaris is a significant contributor to equinus. Data will be collected from 42 children undergoing surgical intervention for ankle equinus. Subjects will be randomly allocated into two groups of equal size: 1) plantaris lengthened before the lengthening in the gastrocsoleus and 2) plantaris lengthened after gastrocsoleus lengthening. All surgical procedures for each patient will be completed in a single setting. Ankle range of motion will be measured at several intervals during surgery. We will measure the same outcome in each group. The outcome is maximum passive ankle dorsiflexion (upwards bend of the ankle) with the knee straight. We expect that maximum passive ankle dorsiflexion will significantly increase after lengthening of the plantaris. Understanding the contribution of the plantaris muscle in ankle equinus could lead to significant improvements in the treatment of children with tight ankles.
• Ability to provided informed consent/assent in English.
• Pediatric patients (4-17 years) who have consented for surgery for the management of equinus contracture \* (either TA lengthening or GN recession) at the Stollery Children's Hospital
• Known underlying diagnosis of any of the following: idiopathic toe walking, cerebral palsy, hereditary spastic paraparesis, traumatic brain injury, spinal cord injury/tethering, hereditary sensory-motor neuropathy, stroke
• Ability to maintain hindfoot and midfoot neutral during assessment
• Passive plantarflexion on affected side greater than 20° and greater than degree of equinus contracture.
⁃ Note: may be isolated or in conjunction with other orthopaedic procedures; in bilateral ankle equinus procedures, data will be collected bilaterally, but included as a single participant (i.e., single randomization).