Scientific Understanding of the Induced Membrane Technique: Current Status and Future Directions

Modern Management of Severe Open Fractures of the Extremities: The Role of the Induced Membrane Technique

➢ The administration of antibiotics, revascularization, effective initial debridement, stabilization, and dead-space management are important time-dependent, acute actions.➢ Following the adequate resuscitation of the patient and the local soft tissues, the first stage of the Masquelet technique is performed together with the definitive coverage of the soft-tissue defect.➢ The optimal time for the second stage (grafting of the bone defect) depends on the progress of the soft-tissue reconstruction and the overall state of the patient. It is usually at 6 to 14 weeks.➢ Bone graft involves cancellous autograft; depending on the volume of the defect, it can be acquired using different donor sites and methods and can be combined with cancellous allograft, bone substitutes, bone marrow aspirate, and inductive molecules.➢ Bone healing is independent of the size of the defect, assuming that revascularization of the graft material has not been disturbed.➢ The development of signs of a fracture-related infection in the clinical setting of a severe open fracture dictates surgical treatment and pathogen-specific antibiotics, debridement of the membrane and the surrounding soft tissues, and reinitiation of the staged process of limb salvage.➢ The results of staged management of severe open fractures with bone defects are reproducible and good.

Treatment of a Ballistic Radius Fracture with Segmental Bone Loss Using the Masquelet Technique in a Child: A Case Report

CASE

A 4-year-old boy sustained an accidental self-inflicted gunshot wound to the left forearm. Radiographs revealed a comminuted mid-diaphyseal ballistic radius fracture with a critical-sized bone defect. The fracture was treated with the placement of a flexible intramedullary nail and antibiotic cement spacer, followed by second-stage bone grafting and open reduction and internal fixation of the radius 6 weeks later. Four months after the second-stage procedure, the radial defect healed appropriately without complications.

CONCLUSION

In this case of a pediatric comminuted mid-diaphyseal radius fracture with bone loss, the induced membrane technique resulted in healing across a critical-sized bone defect.

Simultaneous induced membrane technique to reconstruct an obliterated floating knee

The induced membrane technique, first described by Masquelet, is a powerful surgical approach that can be used to address segmental bone loss of various aetiologies. Despite ongoing debate regarding optimal delivery, the indications and limits of its application have been tested in increasingly complex situations, highlighting its considerable potential.

We present a case of a devastating open lower limb injury with simultaneous femoral and ipsilateral tibial bone loss including articular injury on both sides of the joint. The Masquelet technique was used to successfully address both segments of bone loss within the same limb.

The Basic Science Behind the Clinical Success of the Induced Membrane Technique for Critical-Sized Bone Defects

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The induced membrane technique (IMT) takes advantage of an osteoinductive environment that is created by the placement of a cement spacer into a bone defect.

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Most commonly, a polymethylmethacrylate (PMMA) spacer has been used, but spacers made from other materials have emerged and achieved good clinical outcomes.

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The IMT has demonstrated good results for long-bone repair; however, more research is required in order to optimize union rates as well as delineate more precise indications and surgical timing.

Bone defects are repaired by enhanced osteogenic activity of the induced membrane: a case report and literature review

Background

The induced membrane technique (IMT) is an effective strategy to repair bone defects and involves a two-stage set of surgical procedures. Although the IM has osteogenic activity, bone grafting is necessary in standard IMT. Bone defects repaired completely by osteogenic activity of the IM alone without bone grafts are rare.

Case presentation

We present a case of infected fractures and bone defects of the ulna and radius treated with IMT. After the first stage using polymethylmethacrylate (PMMA) beads, X-rays showed that new callus developed after 2 to 4 months, and the defects were repaired completely by 5 months. We also present a literature review on spontaneous osteogenesis of the IM in patients.

Conclusions

We present a case of infected ulnar and radial bone defects that healed by 5 months after the first stage of the IMT using a PMMA spacer. This finding suggests that local associated inflammatory reactions and bone tissue might enhance the osteogenic activity of the IM, causing spontaneous healing of bone defects. This appears to be the first such case reported in the literature.

The induced membrane technique for bone defects: Basic science, clinical evidence, and technical tips

The clinical management of large bone defects continues to be a difficult clinical problem to manage for treating surgeons. The induced membrane technique is a commonly employed strategy to manage these complex injuries and achieve bone union. Basic science and clinical evidence continue to expand to address questions related to the biology of the membrane and how interventions may impact clinical outcomes. In this review, we discuss the basic science and clinical evidence for the induced membrane technique as well as provide indications for the procedure and technical tips for performing the induced membrane technique.

Three-Dimensional Printing-Assisted Masquelet Technique in the Treatment of Calcaneal Defects

Objective

The aim of the present study was to summarize the clinical efficacy of three‐dimensional (3D) printing technology combined with the Masquelet technique in the treatment of calcaneal defects.

Methods

From January 2018 to April 2019, 3D printing combined with induced masquelet technology was used to treat four patients with calcaneal defects, including two men and two women. The patients were aged 22–52 years old, with an average age of 36 years. There were two cases of traffic accident injuries, there was one case of a fall from height, and there was one case of crush injury. CT scans were used to reconstruct the bilateral calcaneus, mirror technology was used to construct the bone defect area, and Materialise 3‐matic software was used to design the calcaneus shaper mold and 3D print the mold. During the operation, the mold was used to shape the bone cement and fill the bone defect. In the second stage, the bone cement was removed and autologous bone was implanted to repair the bone defect. All patients were followed up to observe the effect.

Results

All four patients were followed up for 14 months (range, 10–18 months). There were three cases of infectious bone defects: two cases of Escherichia coli and one case of Pseudomonas aeruginosa. The 3D printed mold was used to shape the bone cement. During the operation, it was found to have a high degree of matching with the defect area of calcaneus. There is no need to adjust it again, and the wound healed well after the first stage. In the second stage of surgery, it was found that the induced membrane formed was complete and of appropriate size; the bone cement was easily removed during the operation. The fracture healing time was 3–6 months, with an average of 4 months. At the last follow up, there was no pain and the patients walked with full weight bearing. The Maryland score was 94 points (range, 88–98 points); three cases were excellent and one case was good. The AOFAS score ranged from 86 to 98, with an average of 92.8 points; three cases were excellent and one case was good.

Conclusion

Three‐dimensional printing technology combined with induced membrane technology is an effective approach for treating calcaneal bone defects.

Induced Membranes for Segmental Mandibular Reconstruction: Case Series and Technique Review

PURPOSE

This article describes the induced membrane technique (IMT) and presents 10 cases in which the technique was applied for segmental mandibular reconstruction.

METHODS

Ten patients requiring segmental mandibular resection were reconstructed using the staged IMT. Mandibular resection, placement of a reconstruction plate and polymethylmethacrylate spacer, was performed. At the second procedure, the spacer was removed through a small incision and particulate autograft from the ilium was placed, in some cases with bone morphogenic protein.

RESULTS

Nine of the 10 patients achieved bony continuity with the IMT. Spacers were designed to optimize mandibular form and future implant-based restoration. All patients have either had implants placed or have adequate bone for implant placement. The average hospital length of stay for both surgeries combined was 3.1 nights.

CONCLUSIONS

The IMT can be successfully used to reconstruct segmental mandibular defects, allowing surgeons to create a neomandible with optimal form both for facial contour and for dental implant-based reconstruction.

Evaluation of global gene expression in regenerate tissues during Masquelet treatment

The Masquelet induced-membrane (IM) technique is indicated for large segmental bone defects. Attributes of the IM and local milieu that contribute to graft-to-bone union are unknown. Using a rat model, we compared global gene expression profiles in critically sized femoral osteotomies managed using a cement spacer as per Masquelet to those left empty. At the end of the experiment, IM and bone adjacent to the spacer were collected from the Masquelet side. Nonunion tissue in the defect and bone next to the empty defect were collected from the contralateral side. Tissues were subjected to RNA isolation, sequencing, and differential expression analysis. Cell type enrichment analysis suggested the IM and the bone next to the polymethylmethacrylate (PMMA) spacer were comparatively enriched for osteoblastic genes. The nonunion environment was comparatively enriched for innate and adaptive immune cell markers, but only macrophages were evident in the Masquelet context. iPathwayGuide was utilized to identify cell signaling pathways and protein interaction networks enriched in the Masquelet environment. For IM vs nonunion false-discovery rate correction of P values rendered overall pathway differences nonsignificant, and so only protein interaction networks are presented. For the bone comparison, substantial enrichment of pathways and networks known to contribute to osteogenic mechanisms was revealed. Our results suggest that the PMMA spacer affects the cut bone ends that are in contact with it and at the same time induces the foreign body reaction and formation of the IM. B cells in the empty defect suggest a chronic inflammatory response to a large segmental osteotomy.

Comparing the outcomes of the induced membrane technique between the tibia and femur: Retrospective single-center study of 33 patients

INTRODUCTION

Bone defects are challenging to treat surgically. The primary objective of our study was to compare the union rate and time to union between the tibia and femur when using the induced membrane technique. The secondary objective was to document how failures were managed.

MATERIAL AND METHODS

This retrospective, single-center study involved 33 patients (23 men, 10 women) who were older than 18 years of age. They were treated surgically for a leg fracture or long bone nonunion (22 tibia, 11 femur) using the induced membrane technique between January 2011 and December 2016 and had a complete follow-up. The minimum follow-up was 1 year for fractures and 2 years for non-union cases. Bone union was defined as the presence of at least two cortices with bridging on two radiographic views and return to full weight bearing.

RESULTS

The mean patient age was 38.3±15.5 years (18-72). The mean bone defect size was 7.9±5.0cm (2.3-18.0). The mean follow-up was 3.3±1.8 years (1-7.2). The union rate was 61% (20 patients). The mean time to union was 10±6.4 months (3-23). The time to union was significantly longer in the tibia (11.6±6.9 months [3-23]) than in the femur (6.3±2.9 months [3.4-10.3]) (p=0.025). The failure rate did not differ between the tibia and femur. Nine of the 13 patients (69%) in which the treatment failed were reoperated; 7 of them underwent nonunion treatment (78%) and 2 underwent amputation (22%). The other 4 patients were waiting for an infection to resolve before being reoperated.

CONCLUSION

The induced membrane technique is an effective surgical procedure for large bone defects in both the tibia and femur. However, the time to union was shorter in the femur than the tibia in our cohort.

LEVEL OF EVIDENCE

IV, retrospective study.

A load-sharing nail - cage construct may improve outcome after induced membrane technique for segmental tibial defects

INTRODUCTION

Induced membrane technique (IMT) is a well-established technique for treating segmental bone defects. Different variations of the technique have been described. Our objective was to evaluate radiological and functional outcome with IMT using a nail - graft filled titanium cage construct for segmental traumatic bone defects of the tibia.

PATIENTS AND METHODS

26 adult patients with moderate (> 5 cm) or large (> 10 cm) segmental tibial defects after acute open fractures or implant related infected nonunions underwent the procedure. The technique involved 2 stages. After standard debridement +/- implant removal and application of an antibiotic loaded cement spacer in stage 1, the second stage included placement of an intramedullary nail across the defect and an impacted graft filled titanium mesh cage was used to reconstruct the bone defect. Radiographic evidence of bony union, time to painless un-assisted weight bearing, return to work and functional evaluation with lower extremity functional scale (LEFS) were assessed.

RESULTS

5/26 cases were excluded due to failure in controlling infection. 100% union rates were achieved in the remaining 21 patients. 2 patients (9.5%) required repeat bone grafting. The mean time to painless un-assisted painless weight bearing was 26 ± 9.2 days and the mean time to return to work was 45 ± 12.5 days. The mean LEFS at a mean follow up of 27 months was 67 ± 4.7.

CONCLUSIONS

Excellent union rates with good functional restoration can be achieved after IMT using the nail - cage construct for segmental tibial defects. Persistent infection is the biggest impediment for successful execution of the technique. Addition of a cage may also improve short-term functional outcome in terms of ability to weight bear and early return to work.

Prevention of the Infected Fracture: Evidence-Based Strategies for Success!

There is a significant burden of disease associated with infected fractures, and their management is challenging. Prevention of infection after musculoskeletal trauma is essential because treatment of an established infection continues to be a major obstacle. Despite the need for evidence-based decision making, there is a lack of consensus around strategies for prevention and surgical management of the infected fracture. The current evidence for the prevention of the infected fracture is reviewed here with a focus on evidence for antibiotic therapy and debridement, the induced membrane technique, management of soft-tissue defects, patient optimization, and adjuncts to prevent infection.