Post-Op Orthotics: Can They Have An Impact?

David J. Levine, DPM, CPed

   The patient was definitely more comfortable and functioned better with the orthotic devices than without, but the pain continued. Over the course of a few months, her situation gradually deteriorated further. At this point, the treating physician considered a custom AFO but obtained a MRI first. The MRI indicated partial tearing of the tibialis posterior tendon with extensive tenosynovitis. Due to the progressive nature of her deformity, the pain and the lack of improvement with conservative care, the patient was eager to pursue surgical intervention.

Understanding The Impact Of Surgical Procedures On The Patient’s Post-Op Biomechanical Needs

Surgery consisted of tendon repair, a calcaneal osteotomy as well as an osteotomy of the medial cuneiform. Since the bunion was an issue at times as well, the surgeon performed a first metatarsal head osteotomy as well and there were no complications.

   The patient proceeded to undergo physical therapy following the surgery and had a typical course of nonweightbearing with gradual return to activity. Unfortunately, while she was recovering from surgery, she continued to have left foot pain and continued to have a limp. She had difficulty making it through the day without severe pain, In addition, she started to complain of low back and hip pain on the left side. The surgery was over. The foot had healed. The next step was biomechanical assessment.

   Her postoperative examination revealed very little subtalar joint range of motion within the frontal plane. She exhibited a resting varus position to the foot. In addition, the first MTP joint exhibited very little movement within the sagittal plane with approximately equal dorsiflexion and plantarflexion. In relaxed stance, the hallux did not purchase the ground effectively. All of these changes indicated a significant difference between her preoperative and postoperative foot. Prior to surgery she had functional orthotic devices with the main purpose being to control the excessive pronation of the left foot. Now with the mechanics of her foot surgically altered, her needs were much different. She could no longer tolerate the same semi-rigid orthotic on either foot.

What The Post-Op Gait Analysis Revealed

The treating physician performed video/computer gait analysis in order to better identify the issues at hand. This included F-Scan analysis and digital video analysis from four different camera views while the patient walked upon the gait platform. By integrating the two, one can correlate body function and position with foot function and position. It is often the foot that is the chief complaint but the foot can affect the rest of the body or the body can affect the foot. We need to be in the habit of looking at the entire body when assessing foot function.

   Gait analysis findings included a very short center of force traveling through the operated left foot. This indicated difficulties with active and passive propulsion. She was apropulsive primarily because of the lack of motion from the first MTP joint as well as the fact that she was having difficulty with pronating at heel strike. The patient exhibited inversion at heel strike mainly because of the inverted attitude of the entire foot. This finding was unchanged from the preoperative assessment. This was also the position the foot assumes just prior to heel strike. Since the ground is flat, there was a large pronatory force being placed on the subtalar joint. With lack of motion at the subtalar joint, compensation was forced to occur elsewhere such as the midtarsal joint and the first ray.

   Taking all of these considerations into account, the clinician needed to fabricate a new device for the left foot. Given that the patient now has less motion in the foot, she would no longer be able to tolerate the semi-rigid material. Softer and more flexible devices would be better tolerated. As is often the case, feet with restricted motion do better with softer devices and feet with hypermobility do better with more rigid devices. Her right foot did not change but since the clinician was selecting new orthotic material, a new pair of devices was necessary. If the clinician did not replace the right orthotic, there would be different thicknesses that would present other issues.

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