First Metatarsal Pathology: Can An Implant Provide A Long-Term Solution?

Author(s): 
By Kerry Zang, DPM, Shahram Askari, DPM, A’Nedra Fuller, DPM, and Chris Seuferling, DPM
However, given the average length of time (9.1 years) since the implants were placed, we felt this type of questioning would be sufficient to demonstrate either the success or failure of the implant. Step-By-Step Pearls For Using The Bio-Action Implant To begin, make a dorsal curvilinear incision over the first MPJ, exposing the head of the metatarsal and the base of the proximal phalanx. Perform a dorsal capsulotomy according to one’s preference. Once the head of the first metatarsal and the base of the proximal phalanx are exposed, one may remove the hypertrophic changes about the first metatarsal head and rasp the remaining bone smooth. A key component to the success of the Bio-Action Implant is the position of the metatarsal component relative to the second metatarsal head. One must remove enough bone from the metatarsal in order to preserve and/or restore the natural metatarsal parabola. However, minimal osseous resection is critical in order to preserve the sesamoid apparatus as well as the flexor/extensor function. Since this is a joint destructive procedure, surgeons must resect the prominent dorsolateral, dorsal, dorsomedial and medial aspects of the metatarsal to exactly match the circumference of the metatarsal component. Removing this bone will minimize the possibility of osseous impingement and diminish the potential for recurrent bony overgrowth. Mark the center of the respective medullary canals with an awl through the centering guides in order to facilitate acceptance of the implant stems. Drill a guide hole with a football/egg shaped burr parallel to the shaft of the respective bone. One may make this evacuation in the presence of any previous fixation or other implanted device (wire/anchor), provided there is sufficient osseous structure for the implant stem support. Use the implant sizers to ensure proper implant selection and to estimate the range of motion within the joint. When there are some questions as to which implant size to choose (large or small), we feel the best outcome is achieved with the smaller size. This allows the surgeon to skive off any additional overhanging bone, further minimizing the possibility of bony overgrowth. Following proper implant selection, proceed to resect any overhanging bone on the metatarsal about the trial flanges to prevent impingement. When properly seated, the head of the metatarsal component should be slightly shorter clinically than the second metatarsal head. This allows for minimal disruption of the weightbearing surface of the first metatarsal and preserves the metatarsal parabola. Double-check the range of motion within the joint. Copiously irrigate the operative side and place the implants within the appropriate impactor. Again, check the range of motion within the joint and close the capsule with the suture of choice. If the extensor hallucis is contracted, one may lengthen it to a functional position. Close the tissue layers and secure them according to preference. Apply a mild compression with the hallux placed in a functional position. Another key to the success of the Bio-Action Implant is immediate, postoperative, passive range of motion. Daily sagittal plane range of motion exercises, performed by the patient or caregiver, are crucial to minimizing the length of the overall recovery period. Case Study: When A First MPJ Arthrodesis Fails To Relieve Pain A 67-year-old female presented with the chief complaint of difficulty ambulating and pain in the area of her left great toe joint. She related no acute trauma nor an accident. The patient did have a 25-year history of rheumatoid arthritis. She noted that she had previously undergone first MPJ arthrodesis of the left foot two years ago but it did not relieve her symptoms. In fact, she had more pain in the great toe due to a fixed malalignment of the first ray. Her goal was to become as pain free as possible and to have some range of motion restored in her great toe joint. A physical exam of the left foot revealed a solid fusion of the first MPJ with a slight valgus rotation. The lesser MPJs exhibited a decreased range of motion with some fibular deviation. Neurovascular status was intact and within normal limits as were the rearfoot and ankle joint range of motion. Radiographs demonstrated a four-hole plate using the load-screw technique with little anatomical shaping to accommodate adequate fusion position in the first MPJ area. We also noted resection of the lesser metatarsal heads.

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