Treating A Non-Union Of A Second Metatarsal Fracture

Author(s): 
H. John Visser, DPM, Dan Thouvenot, DPM, and Jackson Crough, DPM

These authors detail the diagnosis and treatment of a non-union following a second metatarsal fracture in a 61-year-old patient who was unable to remain non-weightbearing.

Fracture non-unions are a challenging clinical problem. The treatment is often highly individualized and complex. Of the 6 million fractures that occur annually in the United States, 5 to 10 percent are reportedly complicated by non-union or delayed union.1

   Many different risk factors can lead to non-unions. Systemic, patient-derived and iatrogenic risks can all cause decreased healing within bones. Conditions such as smoking, diabetes mellitus, alcohol abuse and increased age are documented risk factors for non-unions.2 Local risk factors include poor blood supply at the fracture site, bone gap, infection, comminution and extensive soft tissue damage.2

   As part of the initial treatment, consider the possible causes for the non-union and then direct treatment toward reducing the risk factor. Conservative treatment options involve casting or bracing along with external bone stimulators and pharmacologic intervention. Surgical management can entail multiple different procedures but the main principles involve adequate resection, correct anatomic alignment and stable fixation.

   However, these cases can be lengthy and difficult. Serious complications including deep infection, hematoma, persistent drainage, neurovascular injury and pain persisting for more than six months are not uncommon.3 The following case discussion involves non-union within a fracture site but one can use similar treatments for failed union following arthrodesis and osteotomies as well.

What You Should Know About The Patient Presentation And Treatment

A 61-year-old Caucasian male presented with pain and swelling to his right foot for a duration of approximately six months. The patient had a history of Parkinson’s disease with dementia and neither he nor his family could recall an initial injury to the foot. He had initially seen another doctor, who placed him in a below-knee immobilizer but the family does admit he was non-adherent in using this modality./

   Upon presentation, the patient had dorsal swelling and pain. Radiographic examination of the foot revealed a comminuted fracture at the base of the second metatarsal. At this time, we placed the patient in a controlled ankle motion (CAM) boot and instructed him on the importance of being adherent. A computed tomography (CT) exam later revealed no signs of healing across the fracture site.

   At this point, we placed an external bone stimulator about the foot and the patient began to use it. He followed up every four to six weeks for serial radiographs to monitor the healing process. After seven months of attempted bone growth stimulation, callus formation had still not occurred across the fracture site.

   A major issue with the patient’s dementia is that it was not possible to keep him non-weightbearing. Accordingly, the operative approach was based on a technique that could allow weightbearing with immobilization. We then scheduled the patient for an inlay bone graft with internal fixation to repair the non-union.

   Upon examination, the second metatarsal position was in appropriate alignment in respect to the third metatarsal. Due to this, repositioning would not have to occur. The surgical approach was to “cut out” the non-union while maintaining the medial, lateral and plantar cortices that would supply structural support. We resected the area and then “backfilled” it with demineralized bone matrix to allow osteoinduction. Calcaneal bone marrow aspirate provided osteogenesis. A dorsal plate acted as a bridge or strut to protect the bone cross stress risers created by early weightbearing.

In Conclusion

Traditionally, the treatment of non-unions has involved surgical fixation with autogenous or allogeneic bone graft. This method allows for stability at the fracture site and provides the biologic components necessary for healing. However, the management of non-unions can become difficult due to the multiple risk factors that can lead to the problem. Understanding the importance of reducing the risk factors can lead to improved outcomes in treatment plans. Although conservative treatment options do have good results, having an understanding of surgical treatment options such as the inlay bone graft are a must.

   Dr. Visser is the Director of the Mineral Area Regional Medical Center Residency Program in Farmington, Mo. and the Director of SSM DePaul Residency Program in St. Louis.

   Dr. Thouvenot is a second year resident at Mineral Area Regional Medical Center in Farmington, MO.

   Dr. Crough is a second year resident at SSM DePaul in St. Louis, MO.

References
1. Griffin XL, Warner F, Costa M. The role of electromagnetic stimulation in the management of established non-union of long bone fractures: what is the evidence? Injury. 2008; 39(4):419-29.
2. Novicoff WM, Manaswi A, Hogan MV, et al. Critical analysis of the evidence for current technologies in bone healing and repair. J Bone Joint Surg Am. 2008; 90(Suppl 1): 85-91.
3. Younger EM, Chapman MW. Morbidity at bone graft donor sites. J Orthop Trauma. 1989; 3(3):192-5.
4. LaPointe SJ. Nonunions. In: Southerland JT, Boberg JS, Downey MS, et al (eds): McGlamry’s Comprehensive Textbook of Foot and Ankle Surgery, fourth edition, chapter 86. Lippincott, Williams and Wilkins, Philadelphia, 2012, pp. 1309-21.

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