Induced-Membrane Technique in the Management of Posttraumatic Bone Defects

Abstract

Background: Critical-size bone defects are defined as bone defects where spontaneous regeneration is not expected without treatment¹. The characteristics of bone defects (etiology, location, size, presence of infection, and soft-tissue conditions) vary greatly and, to be effective, the treatment method should address this variability. The induced-membrane technique, or Masquelet technique, is a method for treating critical-size bone defects^2,3 of various sizes and anatomic locations. It has been used to treat infected and noninfected bone defects and may be performed with a variety of fixation methods^2,3.

Description: The induced-membrane technique is a 2-stage procedure. The first stage consists of debridement followed by insertion of a polymethylmethacrylate (PMMA) spacer in the bone defect. The presence of the PMMA leads to a foreign-body reaction with the development of a thick pseudosynovial membrane that is extremely vascularized and rich in growth factors. The filling of the bone defect with the cement spacer prevents fibrous tissue invasion and allows the development of an optimal vascularized gap for bone-grafting. After 6 to 8 weeks, the membrane around the spacer is carefully opened for the removal of the spacer, which is then replaced by bone graft^2,3, which can be expanded with allograft or biomaterials.

Alternatives: Alternatives include vascularized or nonvascularized autologous bone graft, allograft, bone transport methods, titanium cages, megaprostheses, shortening, and amputation.

Rationale: Posttraumatic bone defects frequently are associated with soft-tissue injury and infection that impair the local vascularization and the healing potential. The highly vascularized induced membrane may play a role in restoring the local regenerative capacity. Numerous studies have demonstrated its successful use in the treatment of posttraumatic bone defects in the hand, forearm, humerus, femur, tibia, and foot. The induced-membrane technique is especially advantageous in the treatment of infected bone defects because the presence of the spacer helps in the treatment of the infection by reducing dead space, acting as a local antibiotic carrier, and promoting some degree of bone stability^3-5.

Fig. 1

Figs. 1 through 10 A 35-year-old man who was involved in a motorcycle accident was treated initially in another hospital, where he underwent orthopaedic damage-control surgery and then was transferred to our institution after 5 days. (This case was not included in our original study of the technique.) Fig. 1 Preoperative radiograph (Fig. 1-A) and appearance of the soft tissue (Fig. 1-B) on day 11 after the injury, when the external fixator on the left femoral fracture was primarily converted to a reamed intramedullary nail.

Fig. 2

On day 16 after the injury and 5 days after internal fixation of the femoral fracture, the patient returned to the operating room because of the suspicion of infection. Fig. 2-A Preoperative radiograph. Fig. 2-B Preoperative appearance of the soft tissue.

Fig. 3

Day 31 after the injury. Infection with Enterobacter cloacae was confirmed. The patient was using an antibiotic (meropenem) chosen on the basis of culture and had already undergone 3 debridements. Fig. 3-A Preoperative appearance of the soft tissue. Fig. 3-B Intraoperative photograph showing infection in the medullary canal. The intramedullary nail was removed, and the canal was reamed. Debridement of bone and soft tissue resulted in a partial bone defect with an estimated size of 6 cm (12 cm involving 50% of the bone diameter). Fig. 3-C Postoperative radiograph. An intramedullary PMMA-with-antibiotic spacer (2 g of meropenem per 40-g package of PMMA) was used in the bone defect. (A smaller spacer was used in this case with active intramedullary infection to allow drainage of the canal). An external fixator was applied to provide bone stability.

Fig. 4

Day 58 after the injury. The spacer had been in the bone defect for 27 days. The patient underwent another procedure to remove the external fixator, obtain tissue samples for culture, and change the spacer in an attempt to prepare for internal fixation. Fig. 4-A Preoperative appearance of the soft tissue. Fig. 4-B Intraoperative photograph showing no clinical signs of infection. Fig. 4-C Radiograph made after removal of the external fixator and insertion of a new intramedullary PMMA-with-antibiotic spacer, which was larger than the previous one to provide stability.

Fig. 5

Day 78 after the injury. Cultures of specimens obtained during previous surgery were negative. Internal fixation was performed with a nail covered with PMMA mixed with antibiotics, and the spacer was changed. Fig. 5-A Preoperative appearance of the soft tissue. Fig. 5-B Intraoperative nail preparation. A chest tube was filled with PMMA mixed with antibiotics. The nail was introduced inside the tube and, after PMMA polymerization, the plastic tube was peeled from the PMMA-coated nail. Fig. 5-C Postoperative radiographs.

Fig. 6

Pieces of the spacer after being broken with a chisel and removed from the bone defect.

Fig. 7

Day 150 after the injury. The spacer was removed and bone graft was applied. Fig. 7-A Preoperative appearance of the soft tissue. Fig. 7-B RIA graft from the right femur. Fig. 7-C Graft inside the induced membrane. Fig. 7-D Membrane closure.

Fig. 8

Induced-membrane maturation 4 weeks (Fig. 8-A), 7 weeks (Fig. 8-B), and 17 weeks (Fig. 8-C) after introduction of the spacer into the bone defect.

Fig. 9

Radiographs showing the state of graft integration immediately (Fig. 9-A), 8 months (Fig. 9-B), 26 months (Fig. 9-C), and 48 months (Fig. 9-D) after application of the bone graft.

Fig. 10

Clinical photographs and radiograph made at the time of the 4-year follow-up.