SLR - December 2016 - Nathaniel Preston
Reference: Azi ML, Teixeira AA, Cotias RB, Joeris A, and Kfuri M Jr. Membrane Induced Osteogenesis in the Management of Posttraumatic Bone Defects. J Orthop Trauma. 2016 Oct;30(10):545–550Reviewed By: Nathaniel Preston, DPM
Residency Program: Grant Medical Center
Podiatric Relevance: Reconstruction of large posttraumatic segmental bone defects of the foot can be especially challenging when attempting to maintain an anatomic metatarsal parabola and basic biomechanical stability foot and ankle. Amputation is always a possible outcome and should be part of the preoperative discussion with the patient, as salvage is often a prolonged process and fraught with difficulties. The reviewed study is focused on the outcomes of segmental defects of the tibia and femur; however, this treatment algorithm using membrane induced osteogenesis is readily applicable to metatarsal and hindfoot bone defects as well.
Methods: The authors reviewed the medical records of 45 consecutive patients treated for posttraumatic bone defects at a single level one center from January 2009 to December 2013. To be included in the study, patients needed to be between the ages of 18 to 60, meet the criteria for ASA physical status I or II, with posttraumatic bone defects of the long bones of the lower limbs, a PMMA spacer used for six to 28 weeks, a minimum of one year of follow-up, complete treatment performed in the unit and consent provided to participate in the study. A total of 33 patients with 34 defects met this inclusion criteria: 19 of the defects were in the tibia and 15 were in the femur. The etiology of the trauma was motor vehicle accident in 88 percent of cases, with a fall or crush injuries comprising the remaining 12 percent.
Staged management was involved in the treatment of the defects using the induced membrane technique described by Masquelet. After initial extensive debridement at the fracture site, a polymethylmethacrylate spacer intraoperatively mixed with 3 g gentamicin and 4 g vancomycin per 40 g was inserted into the resulting void. Systemic antibiotics were administered, and in culture-positive cases, treatment was extended for at least six weeks. After soft-tissue recovery, the spacer was removed, and the void, now enveloped by an induced pseudo synovial membrane, was filled with an autologous iliac crest bone graft.
Plain film radiographs were taken every two months during the first year or until bone union and then annually thereafter. Osseous union was defined as the presence of bridging callus between the bone graft and original bone ends associated with pain-free full weightbearing.
Results: The mean defect size was 6.7 cm, and infection was present in 23 (68 percent) of the bone defects. Bone union was evident in 91 percent of cases (31/34). The average time to union was 8.5 months. In seven of 23 (30 percent) infected cases, the infection recurred, and in three of them, the graft was resorbed resulting in treatment failure; one case resulting in amputation. The size of the bone defect, the bone segment involved and the bone defect type were not shown to be related to the time to achieve bone union.
In the patients who achieved bone union, mobility was often reduced compared with the contralateral side. This was most common in the ankle joint, where 71 percent of patients were affected. Additional soft-tissue reconstruction was required in 11 infected bone defects, all of which involved the tibia (one fasciocutaneous flap and 10 local muscle flaps involving the gastrocsoleus complex).
Conclusions: The staged induced membrane technique is a reliable method for the management of posttraumatic bone defects in the lower extremity. The technique has been shown to effectively achieve osseous union at a rate not directly related to the size of the initial defect. The strength of membrane induced osteogenesis, which is suitable for both infected and noninfected cases, lies in its simplicity and reproducibility.