Management of an 11-cm Femoral Diaphyseal Defect Secondary to Chronic Osteomyelitis Using the Induced Membrane Technique in a 14-Year-Old Girl: A Case Report

Introduction

Chronic osteomyelitis after open fracture remains a difficult problem in orthopedic surgery because eradication of infection, removal of necrotic bone, restoration of mechanical stability, and reconstruction of segmental bone loss must all be achieved to obtain healing [1–3]. Pin tract infection is one of the most common complications of external fixation, and in severe cases it can progress to chronic osteomyelitis, especially when infection persists in the setting of unstable fixation or repeated surgical intervention [1,2]. In posttraumatic long-bone infection, soft-tissue injury, impaired local blood supply, bacterial contamination, and biofilm formation on necrotic tissue all contribute to persistence of infection and nonunion [4–6].

Radical debridement is the cornerstone of treatment for chronic osteomyelitis, but adequate excision of infected and devitalized tissue frequently creates a large segmental bone defect [3,7,8]. Such defects are particularly difficult to reconstruct in the femur because of its load-bearing function and the need to restore both alignment and durable mechanical stability. Rosslenbroich et al reviewed current treatment strategies for diaphyseal long-bone defects and emphasized that defects larger than 3 cm in the lower limbs usually require reconstruction rather than simple grafting or shortening. They also noted that available options include repair techniques based on distraction osteogenesis and reconstructive techniques such as vascularized bone grafting and the Masquelet technique [9].

The induced membrane technique, also known as the Masquelet technique, is a 2-stage reconstructive approach in which an antibiotic-loaded polymethylmethacrylate spacer is first implanted after debridement, followed by later graft-based reconstruction within the biologically active induced membrane [10]. Wong et al described this method as the use of a temporary cement spacer followed by staged bone grafting, and in their clinical series of 9 posttraumatic bone defects, osseous consolidation was achieved in all cases. Their report also highlighted key technical principles, including stabilization and alignment at the first stage, followed by removal of the spacer and grafting within the membrane at the second stage [11]. In contrast, Gao et al reported that augmentative locked plating with bone grafting was effective for selected femoral diaphyseal nonunions after nailing, with bony union achieved in all 13 patients in their series. However, that study mainly addressed aseptic femoral diaphyseal nonunion after prior nailing rather than extensive infected segmental bone loss [12].

This method has shown favorable outcomes in traumatic and septic bone defects [10,11]. Reports describing reconstruction of large infected femoral diaphyseal defects in adolescents remain limited [13]. This report describes staged reconstruction of an 11-cm femoral diaphyseal defect secondary to chronic osteomyelitis in a 14-year-old girl using the induced membrane technique, with emphasis on surgical sequence, grafting strategy, and short-term functional outcome.

Case Report

A 14-year-old girl sustained a right open femoral shaft fracture after a motor vehicle accident (Figure 1). The injury was classified as a Gustilo-Anderson type II open fracture [14]. Initial treatment at an outside hospital consisted of irrigation and debridement of the right thigh wound and external fixation of the right femur under general anesthesia. After surgery, a small amount of purulent discharge developed around the proximal pin site of the lateral external fixator. Local wound care with normal saline and hydrogen peroxide was performed, and the discharge resolved before discharge. The patient then underwent regular postoperative follow-up (Figure 2).

At 6 months after the initial injury, radiographs showed nonunion of the right femoral shaft fracture, and the patient was referred to our hospital for further treatment. At presentation, she had a temperature of 38.3°C, a white blood cell count of 8.49×109/L, a high-sensitivity C-reactive protein level of 18.21 mg/L, and an erythrocyte sedimentation rate of 58 mm/h, indicating active infection. Magnetic resonance imaging was performed to evaluate the extent of devitalized bone and soft-tissue involvement associated with chronic osteomyelitis (Figure 3). Based on the clinical and imaging findings, the lesion was classified as Beit CURE type B4 [15]. The preoperative diagnosis was chronic osteomyelitis with infected nonunion of the right femoral diaphysis. The overall clinical timeline, including the initial injury, diagnosis of infected nonunion, staged reconstruction, and follow-up, is summarized in Figure 4.

The first-stage reconstruction was then performed. Intraoperatively, fusiform and circumferential swelling with purulent discharge was identified along the previous fixation tract. A 20-cm anterolateral femoral incision was made to expose the nonunion site, where extensive scar tissue and purulent material were present around the fracture ends and within the fixation tract. Soft tissue from the fracture site was sent for pathological examination, which showed tissue necrosis with multifocal neutrophil infiltration. Intraoperative tissue cultures grew methicillin-resistant Staphylococcus aureus, supporting the diagnosis of active infection. Approximately 6 cm of sclerotic, avascular bone was identified at the proximal fragment and approximately 5 cm at the distal fragment. Radical debridement and sequential osteotomy were performed until punctate cortical bleeding (“paprika sign”) was observed at both ends, resulting in an approximately 11-cm segmental femoral defect. Through the greater trochanteric entry point, the medullary canal was reamed to 12 mm. A locked intramedullary nail coated with vancomycin-loaded bone cement was inserted into the proximal and distal femoral segments. Limb length was restored with approximately 10 mm of distraction, and the nail was locked. Additional vancomycin-loaded cement was molded around the nail to fill the defect site (Figure 5). Intravenous vancomycin was continued postoperatively until discharge, after which oral linezolid was prescribed.

Nearly 3 months after the first-stage procedure, the patient was readmitted for second-stage reconstruction. Physical examination showed that the lengths of both lower limbs were essentially equal. Autologous graft was harvested from the left femur using a reamer-irrigator-aspirator system (Figure 6), and additional cancellous bone was harvested from the right iliac crest. During the second-stage procedure, the cement spacer and previous intramedullary nail were removed, the nonunion site was refreshed, and the medullary canal was reamed to 14 mm. A new intramedullary nail (13 mm in diameter and 380 mm in length) was inserted and secured with 5 locking screws under fluoroscopic guidance. The femoral defect was then filled with morselized autologous bone graft, and the induced membrane was closed over the grafted segment (Figure 7).

Serial laboratory findings showed overall improvement in leukocyte count, neutrophil percentage, erythrocyte sedimentation rate, and high-sensitivity C-reactive protein during treatment, despite transient postoperative increases after both procedures. Hemoglobin gradually recovered during follow-up (Table 1).

At 6 months after the second-stage procedure, the surgical incision had healed well without redness, drainage, tenderness, pain, or abnormal mobility. Partial weight-bearing was initiated at 2 weeks after the second-stage procedure and progressed to full weight-bearing during follow-up. The patient had resumed normal daily activities and was fully weight-bearing at the final follow-up. Follow-up radiographs showed satisfactory position of the grafted bone, progressive healing of the femoral defect, and no radiographic evidence of recurrent osteomyelitis (Figure 8).

The patient’s medical history was notable for bipolar affective disorder treated with olanzapine and escitalopram, as well as chronic nicotine-containing electronic cigarette use. These factors may have had a negative influence on treatment adherence and bone healing, although their precise contribution in this case could not be determined.

Discussion

This case highlights 3 practical points. First, radical debridement remains the foundation of treatment for chronic posttraumatic osteomyelitis because eradication of infection is essential before definitive reconstruction can be attempted [7,8]. In the present case, the diagnosis of active infection was supported by fever, elevated inflammatory markers, pathological findings, and positive intraoperative cultures for methicillin-resistant Staphylococcus aureus. Second, the induced membrane technique can be used for staged reconstruction of a large infected femoral diaphyseal defect in an adolescent when adequate mechanical stability and sufficient autologous graft are achieved. Third, careful follow-up is required to document infection control, graft incorporation, and functional recovery.

In the present case, radical debridement resulted in an approximately 11-cm femoral diaphyseal defect. Reconstruction of such defects is challenging, especially in a load-bearing long bone such as the femur. Rosslenbroich et al [9] reviewed current treatment strategies for diaphyseal long-bone defects and emphasized that lower-limb defects larger than 3 cm usually require formal reconstruction rather than limited grafting or acute shortening. They also summarized the major reconstructive options for these defects, including bone transport, vascularized bone grafting, and the Masquelet technique. In our patient, we selected the induced membrane technique because it allowed thorough debridement in an infected field, temporary local antibiotic delivery using a cement spacer, stable internal fixation, and delayed graft-based reconstruction after control of infection, while also avoiding prolonged dependence on external fixation.

The timing of the second stage remains controversial. In this case, second-stage reconstruction was performed nearly 3 months after the initial debridement and spacer placement. Wong et al described the Masquelet technique as staged bone grafting after temporary cement spacer placement and reported a mean interval of 48.5 days between the 2 stages in their clinical series, with successful consolidation in all cases. Other reports have suggested that the biological activity of the induced membrane is greatest during the early weeks after spacer implantation, although successful reconstruction has also been reported after longer intervals [11]. Therefore, the optimal timing should be individualized according to soft-tissue condition, control of infection, inflammatory markers, and surgical readiness. In our patient, the second stage was performed after clinical improvement and a downward trend in inflammatory markers had been observed.

The present case also supports the value of combining stable intramedullary fixation with an abundant autologous graft. At the second stage, graft material was obtained using a reamer-irrigator-aspirator system and supplemented with cancellous bone from the iliac crest. This approach provided a large volume of autologous graft for defect filling without the use of synthetic bone substitute. Progressive radiographic healing and recovery of full weight-bearing were achieved during follow-up, suggesting that this grafting strategy was appropriate in this adolescent patient.

Comparison with previous reports is informative. Wong et al [11] reported successful treatment of posttraumatic bone defects using staged spacer placement and later grafting within the induced membrane, but their series included defects ranging from 2 to 8 cm and did not focus specifically on adolescent femoral diaphyseal defects. Gao et al [12] reported that augmentative locked plating with bone grafting achieved union in all 13 cases of selected femoral diaphyseal nonunion after nailing, highlighting the importance of both mechanical stability and biological augmentation. However, their cohort mainly involved aseptic femoral diaphyseal nonunion after prior nailing rather than extensive infected segmental bone loss. By contrast, our patient had chronic infection with sequestrum formation and required resection of an approximately 11-cm segment of necrotic femoral shaft. This distinction is important because our case was not a routine femoral nonunion revision; rather, it required staged reconstruction of an infected segmental defect. Chi et al [16] reported successful management of chronic osteomyelitis after femoral fracture using a single-stage reconstructive strategy with vascularized fibular grafting. Lavía et al [17] described reconstruction of a tibial diaphyseal defect using the Masquelet technique after severe open trauma. Yaokreh et al [13] reported staged reconstruction of a 25-cm humeral defect secondary to chronic osteomyelitis in a 12-year-old boy using the induced membrane technique combined with autologous cancellous bone graft and a free avascular fibular graft. Compared with these reports, the present case is notable for involving an adolescent patient with an infected 11-cm femoral diaphyseal defect reconstructed using an antibiotic-loaded cement spacer, intramedullary fixation, and autologous graft harvested with a reamer-irrigator-aspirator system.

This report has limitations. It describes a single patient with relatively short-term follow-up, and the findings cannot be generalized. Nevertheless, the case suggests that the induced membrane technique can be an effective option for reconstruction of large post-infectious femoral diaphyseal defects in adolescents when radical debridement, stable fixation, and adequate autologous grafting are achieved.

Conclusions

The induced membrane technique may be an effective method for staged reconstruction of large post-infectious femoral diaphyseal defects in adolescents. Radical debridement, stable fixation, and sufficient autologous grafting were essential for infection control and bone healing in this case.