We showed that the early debridement and internal fixation with the Masquelet technique could effectively control infection, relieve patients’ symptoms, achieve bone healing, and facilitate early functional exercise in patients with CCHOM.
The Beit-CURE (BC) classification is the first classification intended solely for CCHOM [1, 8–10]. It considers the presence of both sequestrum and involucrum. Some studies have confirmed that the BC classification can guide surgical strategy and help predict length of inpatient treatment and number and type of procedures required [8–10]. However, in our hospital, most of the patients had undergone one or more surgeries in local hospitals before they were admitted to our hospital. According to the BC classification, they should be categorised as unclassifiable, and therapy recommendations are not conceivable. Cierny–Mader’s classification is based on the extent of infection (medullary, superficial, localised, diffuse) and host status (healthy, compromised immune system, failed immune system) [19, 20]. This is the most widely used classification for chronic osteomyelitis. It represents the pathological progression of osteomyelitis and is useful in planning treatment strategy [13]. Although it is mainly suitable for adult patients, it can be applied to the paediatric population as well; namely, in this study, we adopted the different strategies of debridement and stabilisation according to this classification.
The timing of debridement of CCHOM is controversial. Some authors believe that the intact involucrum develops, which can provide good stability, before sequestrectomy is required to reduce the risk of complication such as pathological fractures, deformities, and segmental bone defects [5, 11, 13]. Other authors, however, advocate for the early debridement to control infection, create a better environment for the periosteum to respond, and minimise damage to the surrounding soft tissues [1, 5]. In our cases, due to the application of internal fixation, the stability of the affected limb could be maintained; thus, debridement could be performed after diagnosis is confirmed, regardless of whether involucrum has formed or not. This undoubtedly shortened the treatment period and accelerated the recovery of the children.
The Masquelet’s technique is regarded as the “gold standard” for treating various types of long bone defects in adults and children [21, 22]. Auregan et al. [23] found that paediatric patients treated with the Masquelet technique had a 58% success rate, which increased to 87% when iterative surgery was considered. Canavese et al. [24]and Rousset et al. [25] reported five and eight children with chronic osteomyelitis treated by the Masquelet technique, respectively, and achieved satisfactory treatment results. Shen et al. treated 26 children with chronic osteomyelitis with the Masquelet technique, and the bone defects were healed in 4.0–5.0 months after the operation. Wang et al. [26] achieved good clinical efficacy in treating chronic osteomyleitis in both adult and paediatric patients. These reports confirm that the Masquelet technique is an effective treatment for chronic osteomyelitis in children, but there have been no literature reports on CCHOM.
The application of internal fixation is typically contraindicated in the treatment of chronic osteomyelitis. However, some scholars have used antibiotic-loaded bone cement–coated plate as a temporary fixation after debridement, which can kill planktonic bacteria and inhibit the formation of biofilms[16, 18]. In the second stage, the application of internal fixation for bone reconstruction facilitated the reduction of care, avoidance of pin tract infections, and early functional exercise. In this study, for the C–M type III patients, according to the protocol by Kinik et al. [27], more than 30% of cortical bone removal for debridement necessitates prophylactic fixation to prevent iatrogenic fracture risk. For the C-M type IV, we used locking plates for internal fixation in the first and second stages. This did not increase the chance of infection recurrence, but it reduced the difficulty of postoperative care and improved the comfort of the child. In the second stage, significant solidification of the bone graft was seen 2 to 3 months after the second stage of surgery, so that full weight-bearing could be gradually achieved. Children could return to society early and participate in classroom learning and activities, which is beneficial to the physical and mental development, especially in younger patients.
In the second stage of the Masquelet's technique, the need for a large amount of autologous cancellous bone graft to reconstruct bone defects is a limiting factor, especially in very young children. The application of some alternative materials has been tried in clinical practice. Fitoussi et al. [28] used autologous cancellous bone particles combined with autologous fibula scaffold to fill the bone defect in the second stage for eight children with post-operative bone defect larger than 15 cm due to primary malignant tumour. All of the bone defects healed within 5.6 (range, 4–8) months. Gouron et al. [29]performed bone reconstruction in 14 children with trauma, tumour resection, or tibial congenital pseudarthrosis. They added allograft bone, biphasic calcium phosphate (BCP) or tibial bone strut to increase the graft volume. Bone union was achieved in 9.5 (range, 2–25) months. Canavese et al. [24] and Rousset et al. [25] used β-tricalcium phosphate (BTP) as a bone graft substitute. Their results showed that BTP was even more effective in osteogenesis than bone graft. Shen et al. [30] used bone marrow concentrator–modified allograft or bone marrow aspirate–mixed allograft to improve the osteogenic ability of allograft. In this study, allograft bone was added as an alternative graft material to increase the graft volume. Prior to use, in accordance with the method reported by Gouron [22, 28], the allograft was immersed in blood from the donor site. Three patients had resorption, and we believe the higher proportion of allogeneic bone was the main reason. Therefore, it is recommended that the proportion of allograft bone does not exceed one-third to avoid hindering consolidation according to an empirical advice of Masquelet [21].
There were several limitations to our study: (1) small sample size; (2) different skeletal sites involved; (3) no comparison with other treatment methods. Thus, additional studies are mandatory.