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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 104 - 104
2 Jan 2024
der Broeck L Geurts J Qiu S Poeze M Blokhuis T
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The optimal treatment strategy for post-traumatic long bone non-unions is subject of an ongoing discussion. At the Maastricht University Medical Center (MUMC+) the induced membrane technique is used to treat post-traumatic long bone non-unions. This technique uses a multimodal treatment algorithm involving bone marrow aspirate concentrate (BMAC), the reamer-irrigator-aspirator (RIA) and P-15 bioactive peptide (iFactor, Cerapedics). Bioactive glass (S53P4 BAG, Bonalive) is added when infection is suspected. This study aims to objectify the effect of this treatment algorithm on the health-related quality of life (HRQoL) of patients with post-traumatic long bone non-unions. We hypothesized that HRQoL would improve after treatment.

From January 2020 to March 2023, consecutive patients who were referred to a multidisciplinary (trauma, orthopaedic and plastic surgery) non-union clinic at the MUMC+, The Netherlands, were evaluated using the Non-Union Scoring System (NUSS). The EQ-5D-5L questionnaire and the Lower Extremity Functional Scale (LEFS) were employed to obtain HRQoL outcomes both prior to and subsequent to surgery, with a follow-up at 6, 18 and 35 weeks.

Seventy-six patients were assessed at baseline (T0), with a mean NUSS of 40 (± 13 SD). Thirty-eight patients had their first follow-up, six weeks after surgery (T1). Thirty-one patients had a second follow-up at 18 weeks (T2), and twenty patients had the third follow-up at 35 weeks (T3). The EQ-5D index mean at baseline was 0.480, followed by an index of 0.618 at T1, 0.636 at T2, and 0.702 at T3. A significant difference was found in the HRQoL score between T0 and T1, as well as T2 and T3 (p<0.001; p=0.011). The mean LEFS significantly increased from 26 before intervention to 34, 39, and 43 after treatment (p<0.001; p=0.033; p=0.016).

This study demonstrated a significant improvement in the health-related quality of life of patients with post-traumatic long bone non-unions after the standardized treatment algorithm following the induced membrane technique.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_8 | Pages 65 - 65
11 Apr 2023
Siverino C Arens D Zeiter S Richards G Moriarty F
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In chronically infected fracture non-unions, treatment requires extensive debridement to remove necrotic and infected bone, often resulting in large defects requiring elaborate and prolonged bone reconstruction. One approach includes the induced membrane technique (IMT), although the differences in outcome between infected and non-infectious aetiologies remain unclear. Here we present a new rabbit humerus model for IMT secondary to infection, and, furthermore, we compare bone healing in rabbits with a chronically infected non-union compared to non-infected equivalents.

A 5 mm defect was created in the humerus and filled with a polymethylmethacrylate (PMMA) spacer or left empty (n=6 per group). After 3 weeks, the PMMA spacer was replaced with a beta-tricalcium phosphate (chronOs, Synthes) scaffold, which was placed within the induced membrane and observed for a further 10 weeks. The same protocol was followed for the infected group, except that four week prior to treatment, the wound was inoculated with Staphylococcus aureus (4×106 CFU/animal) and the PMMA spacer was loaded with gentamicin, and systemic therapy was applied for 4 weeks prior to chronOs application.

All the animals from the infected group were culture positive during the first revision surgery (mean 3×105 CFU/animal, n= 12), while at the second revision, after antibiotic therapy, all the animals were culture negative. The differences in bone healing between the non-infected and infected groups were evaluated by radiography and histology. The initially infected animals showed impaired bone healing at euthanasia, and some remnants of bacteria in histology. The non-infected animals reached bone bridging in both empty and chronOs conditions.

We developed a preclinical in vivo model to investigate how bacterial infection influence bone healing in large defects with the future aim to explore new treatment concepts of infected non-union.


Introduction

20 cases of bone defect have been treated by the induced membrane technique avoiding allograft, microsurgery and amputation

Material and Methods

9 cases of long bone defect (humerus and 2 bones arm) and 11 cases of bone defct at the hand have been included in this multicentric prospective study (3 centers). 11 cases were traumatic, 7 cases were septic non union and 2 cases were tumor. At hand level's bone reached at least one phalanx, and for long bone the mean defect was 5cm (3–11). All cases were treated by the induced membrane technique which consists in stable fixation, flap if necessary and in filling the void created by the bone defect by a cement spacer (PMMA). This technique needs a second stage procedure at the 2nd month where the cement is removed and the void is filled by cancellous bone. The key point of this induced membrane technique is to respect the foreign body membane which appeared around the cement spacer and which create a biologic chamber after the second time. Bone union was evaluated prospectively in each case by an surgeon not involved in the treatment by Xray and CT scan. Failure was defined as a non union at 1 year, or an uncontrolled sepsis at 1 month.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 34 - 34
4 Apr 2023
Kaneko Y Minehara H Nakamura M Sekiguchi M Matsushita T Konno S
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Recent researches indicate that both M1 and M2 macrophages play vital roles in tissue repair and foreign body reaction processes. In this study, we investigated the dynamics of M1 macrophages in the induced membrane using a mouse femur critical-sized bone defect model.

The Masquelet method (M) and control (C) groups were established using C57BL/6J male mice (n=24). A 3mm-bone defect was created in the right femoral diaphysis followed by a Kirschner wire fixation, and a cement spacer was inserted into the defect in group M. In group C, the bone defect was left uninserted. Tissues around the defect were harvested at 1, 2, 4, and 6 weeks after surgery (n=3 in each group at each time point). Following Hematoxylin and eosin (HE) staining, immunohistochemical staining (IHC) was used to evaluate the CD68 expression as a marker of M1 macrophage. Iron staining was performed additionally to distinguish them from hemosiderin-phagocytosed macrophages.

In group M, HE staining revealed a hematoma-like structure, and CD68-positive cells were observed between the spacer and fibroblast layer at 1 week. The number of CD68-positive cells decreased at 2 weeks, while they were observed around the new bone at 4 and 6 weeks. In group C, fibroblast infiltration and fewer CD68-positive cells were observed in the bone defect without hematoma-like structure until 2 weeks, and no CD68-positive cells were observed at 4 and 6 weeks. Iron staining showed hemosiderin deposition in the surrounding area of the new bone in both groups at 4 and 6 weeks. The location of hemosiderin deposition was different from that of macrophage aggregation.

This study suggests that M1 macrophage aggregation is involved in the formation of induced membranes and osteogenesis and may be facilitated by the presence of spacers.