Bone grafting is the main method of treating nonunions.1 The multiple bone graft options available include autogenous bone grafts, allogenic bone grafts, and synthetic bone graft substitutes.2,3 Autogenous bone graft has long been considered the gold standard, as it reduces the risk of infection and eliminates the risk of immune rejection associated with allograft; in addition, autograft has the optimal combination of osteogenic, osteoinductive, and osteoconductive properties.2,4,5 Iliac crest bone graft (ICBG), though the most commonly used autogenous bone graft source, has been associated with infection, hematoma, poor cosmetic outcomes, hernia, neurovascular insults, and chronic persistent pain.6,7 Intramedullary bone graft harvest performed with the Reamer/Irrigator/Aspirator (RIA) system (DePuy Synthes) is a novel technique that allows for simultaneous débridement and collection of bone graft, protects against thermal necrosis and extravasation of marrow contents, and maintains biomechanical strength for weight-bearing.3,4,8,9 Furthermore, RIA aspirate is a rich source of autologous bone graft and provides equal or superior amounts of graft in comparison with ICBG.5-7,10-12
In some cases, RIA is associated with the complication of host bone fracture.4,6,7,11,12 In addition, introducing the reamer may contribute to pain at its entry site and may require violation of local soft-tissue attachments at the hip or knees.4,7,13 In this study, we assessed the possibility of using a new RIA technique to eliminate these adverse effects. We hypothesized that distal femoral nonunions could be successfully treated with the RIA passed retrograde through the nonunion site. This technique may obviate the need for a secondary surgical site (required in traditional intramedullary bone graft harvest), minimize the potential entry-site tissue (eg, hip abductor) damage encountered with the antegrade technique, and yield harvested bone graft in quantities similar to those obtained with the standard technique.
After obtaining Institutional Review Board approval for this study, we retrospectively reviewed the medical records of all patients with a distal femur nonunion treated with autogenous bone grafting between 2009 and 2013. Identified patients had undergone a novel intramedullary harvest technique that involved passing an RIA retrograde through the nonunion site. Data (patient demographics, volume of graft obtained, perioperative complications, postoperative clinical course) were extracted from the medical records. Before data collection, all patients provided written informed consent for print and electronic publication of their case reports.
Technique
The patient was laid supine on a radiolucent table, and the affected extremity was prepared and draped free. A standard lateral incision previously used for the index procedure was employed. After implant removal, a rongeur, curette, and/or high-speed burr was used to débride the distal femur nonunion of all fibrous tissue. After mobilization and preparation of the distal femoral nonunion, varus angulation was accentuated with delivery of the proximal and distal segments of the nonunion into the wound (Figure A).
Six patients underwent 7 separate procedures for distal femoral nonunion. Of these patients, 5 underwent retrograde RIA through the nonunion site, as described above; the sixth underwent antegrade RIA in the traditional fashion and was therefore excluded. One of the 5 patients underwent another bone grafting procedure after the initial retrograde RIA treatment through the nonunion site. Several outcomes were measured: ability to obtain graft, volume of graft obtained, perioperative complications, and feasibility of the procedure.
Mean age of the 5 patients was 40.4 years (range, 22-66 years). Mean reamer size was 13.4 mm (mode, 14 mm), producing an average bone graft volume of 33 mL. There were no intraoperative or postoperative fractures. In 1 case, the reamer shaft broke during insertion and was retrieved with no retained hardware; passage was made with a new reamer shaft. No patient experienced additional pain or discomfort, as there was no separate entry site for the RIA.
Discussion
Bone grafting for nonunion is one of the most commonly performed procedures in orthopedic trauma surgery. Use of an intramedullary harvest system has become increasingly popular relative to alternative techniques. The RIA system is associated with less donor-site pain and provides relatively more bone graft volume in comparison with ICBG harvest.6,7,10,13 Conversely, intramedullary bone graft harvest may be associated with higher risk of host bone fractures, occurring either during surgery (technical error being the cause) or afterward (a result of patient noncompliance or overaggressive reaming).6,7,11,12 Multiple methods of reducing the risk of iatrogenic fracture caused by technical error of eccentric reaming have been described, including appropriate guide wire placement aided by frequent use of fluoroscopy in 2 planes.4 Despite these potential complications and improved donor-site pain complaints in comparison with ICBG harvest, traditional RIA harvest is still associated with pain at the entry site.4,7,13