How To Recreate The Benefits Of Low Dye Strapping With Orthotics
This modification involves dorsiflexing the hallux during the process of obtaining the negative cast. By dorsiflexing the hallux, we apply a retrograde force on the first ray that results in plantarflexion of the first ray. The result is a negative foot impression cast with the subtalar joint in a neutral position, a maximally pronated midtarsal joint and a plantarflexed first ray. In essence, one is obtaining an impression of the foot that is ideally prepared for entry into the propulsive period of the gait cycle. When fabricated properly, the resulting foot orthotic device will promote first ray plantarflexion. Now the orthotic does what the low Dye strapping does, only better. How do we know if this will be enough? Is this right for all patients? The answers to these questions are dependent on the exam. It is important to examine the position and motion of the first ray carefully. Recent literature reveals that the findings of the range of motion exam of the first ray are not predictive as to first ray hypermobility and are not readily reproducible. However, we can still use the results of the exam to get an idea of the position and motion of the first ray, and translate this info into the design of an orthotic. Case Study: A Marathon Runner With A Small Area Of Dorsal Pain A 24-year-old male marathon runner presents with a chief complaint of pain on the dorsal aspect of his left foot in an area about the size of a quarter. The patient relates that he ran his last marathon three months prior to his visit and the pain became quite intense. He was diagnosed with posterior tibialis tendonitis. The patient also relates he was recently diagnosed with a bone spur. The patient has tried NSAIDs, ice and rest with no resolution of his symptoms. He has no other contributory medical conditions. The patient has pain with palpation to the area over the talonavicular joint. He also appears to have a cavus foot. Subtalar joint, midtarsal joint and first metatarsophalangeal joint ranges of motion are all normal. The non-weightbearing examination reveals a positionally plantarflexed first ray. The patient also has a varus of metatarsal heads two through five. Radiographs show signs of a cavus foot with a dorsal exostosis at the talonavicular joint of the symptomatic left foot. I applied a low Dye strapping and instructed the patient to attempt a run. The patient reported that he ran with the taping and his pain was completely alleviated. Based on the radiographic evidence of medial column jamming and evidence that the patient’s first ray was the cause of this jamming (due to his response to the low Dye strapping), I decided to cast the patient for foot orthotic devices. Capturing The Benefits Of Low Dye Strapping With Orthotics How would one recreate the positive results the low Dye strapping provided? Based on our clinical exam, we fabricated a foot orthotic device that incorporated a rearfoot post that corresponded to the patient’s neutral calcaneal stance position. The forefoot was a different matter. We applied an intrinsic forefoot post for metatarsal heads two through five. There was also a cutout within the shell of the foot orthotic device for the first ray. This allowed for more plantarflexion of the first ray relative to the lesser rays. After a break-in period for the foot orthotic devices, we cleared the patient to run in them. In short, using the orthotics alleviated the patient’s symptoms. In Conclusion This patient required something beyond just capturing his first ray plantarflexed in a negative cast. By closely examining this runner’s foot and with the help of the low Dye strapping, we prescribed a foot orthotic device that eliminated the jamming of his medial column by allowing his first ray to plantarflex adequately. There are other means of further promoting first ray plantarflexion in an orthotic. One may employ a cutout beneath the first ray in a forefoot extension, a kinetic wedge under the first metatarsal head, a reverse Morton’s extension or a cutout in the shell of the orthotic itself. The important thing is to listen to what an athletic patient says about wearing a low Dye strapping. Couple that with a careful and thorough clinical exam and the odds are good of creating a foot orthotic device that will provide maximum patient benefit by promoting adequate first ray plantarflexion. Dr. Spencer is an Associate Professor of Orthopedics/Biomechanics at the Ohio College of Podiatric Medicine.