Aims. This study aimed to evaluate the effectiveness of the induced membrane technique for treating infected bone defects, and to explore the factors that might affect patient outcomes. Methods. A comprehensive search was performed in PubMed, Embase, and the Cochrane Central Register of Controlled Trials databases between 1 January 2000 and 31 October 2021. Studies with a minimum sample size of five patients with infected bone defects treated with the induced membrane technique were included. Factors associated with nonunion, infection recurrence, and additional procedures were identified using logistic regression analysis on individual patient data. Results. After the screening, 44 studies were included with 1,079 patients and 1,083 segments of infected bone defects treated with the induced membrane technique. The mean defect size was 6.8 cm (0.5 to 30). After the index second stage procedure, 85% (797/942) of segments achieved union, and 92% (999/1,083) of segments achieved final healing. The multivariate analysis with data from 296 patients suggested that older age was associated with higher nonunion risk. Patients with external fixation in the second stage had a significantly higher risk of developing nonunion, increasing the need for additional procedures. The autografts harvested from the femur reamer-irrigator-aspirator increased nonunion, infection recurrence, and additional procedure rates. Conclusion. The induced membrane technique is an effective technique for treating infected bone defects. Internal fixation during the second stage might effectively promote bone healing and reduce additional procedures without increasing infection recurrence. Future studies should standardize individual patient data prospectively to facilitate research on the affected patient outcomes. Cite this article: Bone Joint Res 2023;12(9):546–558

Background: Increased intramedullary pressure in the femoral cavity causes intravasation of bone marrow content to the circulation which may lead to occlusion of pulmonary vessels and cardiorespiratory dysfunction. A one-step reamer-irrigator-aspirator (RIA) technique has been developed to reduce the intramedullary pressure (IMP) during the reaming procedure. Material and method: In a randomized study in 19 Nor-wegian landrace pigs reamed intramedullary nailing was performed with two different reamer devices. Nine animals were operated with a traditional reamer and ten animals with RIA. One animal in the RIA group was excluded due to a perioperative femoral fracture, and three animals in the traditional group due to a perforation of the distal medial femoral cortex. The intramedullary pressure was registrated with a transducer-tipped pressure monitoring catheter during reaming. Results: The highest intramedullary pressure during reaming was mean 33 mm Hg in the RIA group and 188 mm Hg in the traditional reamer group. This difference was significant (P < 0.05). Intramedullary pressures recorded before surgery, at the opening of the femoral cavity with an awl, by insertion of a guide wire, at insertion of the intramedullary nail, and ten minutes after nail insertion showed no significant differences between the groups. Conclusion: The use of a one-step reamer-irrigator-aspirator technique in the pig femur induced less intramedullary pressure increase than the use of a traditional reamer

Introduction. MSCs have long promised benefits of synthesising bone/cartilage, treating non-unions and potentially accelerating fracture repair. This potential has been tempered by MSC scarcity in the ‘gold-standard’ iliac crest bone marrow aspirate (ICBMA) and the resulting need to expand numbers via cell-culture. Culture of MSCs is time-consuming, expensive and results in cells with a reduced differentiation capacity. The reamer-irrigator-aspirator (RIA) is an innovation designed to reduce intra-medullary (IM) pressures during reaming of long-bones via continuous irrigation and suction. Aspirated contents are passed via a coarse filter, which traps bony-fragments before moving into a ‘waste’ bag - from which MSCs have been previously isolated. We examined liquid and solid phases found in this ‘waste’, performed a novel digestion of the solid phase and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA. Methods. The filtrate ‘waste’ bag from RIA reaming (6 patients) was filtered (70μm) and the solid fraction digested for 60min (37°C) with collagenase. MSCs were isolated from liquid & solid fractions and from 10ml matched ICBMA. Enumeration of MSCs was achieved via colony-forming-unit-fibroblast (CFUF) assay and flow-cytometry on fresh sample using CD45low, CD271+. MSCs were cultured by virtue of their plastic adherence and passaged in standard, non-haematopoietic media. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages with their phenotype assessed with flow cytometry CD33 CD34 CD45 CD73 CD90 CD105. Results. We found MSCs were in all fractions/patients. Using the CFU-F assay median number of colonies: ICBMA=8 (2–21), RIA-liquid=12 (4–41), RIA-solid=115 (67–200) per 200μl of sample. Total yield of cells was calculated from volume of sample: ICBMA=670 (228–4275), RIA-liquid=39000 (16500–83700), RIA-solid=9400 (7210–28475). MSC frequency as a percentage of total cells using flow-cytometry on fresh sample found similar frequencies. MSCs isolated from the RIA phases differentiated into osteogenic, chondrogenic and adipogenic lineages at least as well as ICBMA. Passaged (P2) cells, from all fractions/patients, had a phenotype consistent with other reported sources. Discussion. The RIA filtrate bag is typically discarded at operation. These results show that this ‘waste’ represents a significant source of MSCs that could be isolated for autologous/allogenous use. Concentration of the liquid-phase/brief enzymatic digestion of the solid-phase offers the possibility of large numbers of MSCs being obtained without/with minimal culture expansion

The scarcity of mesenchymal stem cells (MSCs) in iliac crest bone marrow aspirate (ICBMA), and the expense and time in culturing cells, has led to the search for alternative harvest sites. The reamer-irrigation-aspirator (RIA) provides continuous irrigation and suction during reaming of long bones. The aspirated contents pass via a filter, trapping bony fragments, before moving into a ‘waste’ bag from which MSCs have been previously isolated. We examined the liquid and solid phases, performed a novel digestion of the solid phase, and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA.

The solid fraction from the filtrate was digested for 60 minutes at 37°C with collagenase. Enumeration was performed via the colony-forming unit fibroblast (CFU-F) assay. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages, and their phenotypes assessed using flow cytometry (CD33, CD34, CD45, CD73, CD90, and CD105).

MSCs from the RIA phases were able to differentiate at least as well as those from ICBMA, and all fractions had phenotypes consistent with other established sources. The median number of colonies for the three groups was: ICBMA = 8.5 (2 to 86), RIA-liquid = 19.5 (4 to 90), RIA-solid = 109 (67 to 200) per 200 μl. The mean total yield of cells for the three groups was: ICBMA = 920 (0 to 4275), RIA-liquid = 114 983 (16 500 to 477 750), RIA-solid = 12 785 (7210 to 28 475).

The RIA filtrate contains large numbers of MSCs that could potentially be extracted without enzymatic digestion and used for bone repair without prior cell expansion.

Introduction

Therapeutic exploitation of MSCs in orthopaedics has been tempered by their scarcity within ‘gold-standard’ iliac crest bone marrow aspirate (ICBMA) and the resulting need to expand cells in vitro. This is time-consuming, expensive and results in cells with a reduced differentiation capacity. [Banfi 2000] The RIA is a device that provides continuous irrigation and suction during reaming of long bones. Aspirated contents pass via a filter, trapping bony-fragments, before moving into a ‘waste’ bag, from which MSCs have been previously isolated. [Porter 2009] We hypothesised that ‘waste’ RIA bag contains more MSCs than a standard aspirated volume of ICBMA (30 ml). We further hypothesised than a fatty solid phase within this ‘waste bag’ contains many MSCs trapped within the adipocyte-rich stromal network and hence requiring an enzymatic digestion for their efficient release [Jones 2006].

Purpose: Autologous bone grafting is considered the gold standard for multiple orthopaedic indications, including non-union of fractures and other bone defects. Previously autograft was most commonly harvested from the iliac crest, with an estimated complication rate of greater than 10%. New technology, the RIA system, allows harvest of graft material from the medullary canal of the femur. The purpose of this study is to examine the osteo-inductive properties of this human femoral bone graft obtained using the RIA system and the RIA filtrate combined with chronOS (Tricalcium Phosphate). This study will examine whether these materials will induce bone growth when implanted in a rat sub-muscular pouch model.

Method: Three samples were collected from each human subject. These included:

femoral bone graft obtained using the RIA {n=10}

chronOS (alone) was used as control {n=10}. These materials were implanted into a sub-muscular pouch in athymic rats (to eliminate rejection of the xenograft). Rat serum levels of BMP-2, VEG-F, TGF-β and IL-10 were obtained at days 7, 14, 21 and 28. Rats were sacrificed at day 28 and radiographic and histologic examinations and histomorphometric analyses were performed.

Results: Overall, there were no significant differences in BMP-2, VEG-F, TGF-β and IL-10 levels either between groups or between time points. Average serum values for BMP-2 decreased over time for all groups. Histologically and radiographically, all four materials induced new bone production. chronOS alone produced the greatest volume of new bone while RIA reamings alone produced the least. Histological analysis demonstrated formation of normal bone.

Conclusion: The RIA system allowed for harvest of femoral bone graft. This graft induced bone formation and increased osteogenic protein levels when implanted in the rat model. The RIA filtrate, when combined with Tricalcium Phosphate, is equally osteoinductive. Combining reamings with filtrate material may allow large volumes of graft to be produced using this system. This new technology may allow the collection of large volume, osteoinductive grafts without the complications previously described for iliac crest bone graft harvesting.

Aims. Continuous local antibiotic perfusion (CLAP) has recently attracted attention as a new drug delivery system for orthopaedic infections. CLAP is a direct continuous infusion of high-concentration gentamicin (1,200 μg/ml) into the bone marrow. As it is a new system, its influence on the bone marrow is unknown. This study aimed to examine the effects of high-concentration antibiotics on human bone tissue-derived cells. Methods. Cells were isolated from the bone tissue grafts collected from six patients using the Reamer-Irrigator-Aspirator system, and exposed to different gentamicin concentrations. Live cells rate, apoptosis rate, alkaline phosphatase (ALP) activity, expression of osteoblast-related genes, mineralization potential, and restoration of cell viability and ALP activity were examined by in vitro studies. Results. The live cells rate (the ratio of total number of cells in the well plate to the absorbance-measured number of live cells) was significantly decreased at ≥ 500 μg/ml of gentamicin on day 14; apoptosis rate was significantly increased at ≥ 750 μg/ml, and ALP activity was significantly decreased at ≥ 750 μg/ml. Real-time reverse transcription-polymerase chain reaction results showed no significant decrease in the ALP and activating transcription factor 4 transcript levels at ≥ 1,000 μg/ml on day 7. Mineralization potential was significantly decreased at all concentrations. Restoration of cell viability was significantly decreased at 750 and 1,000 μg/ml on day 21 and at 500 μg/ml on day 28, and ALP activity was significantly decreased at 500 μg/ml on day 28. Conclusion. Our findings suggest that the exposure concentration and duration of antibiotic administration during CLAP could affect cell functions. However, further in vivo studies are needed to determine the optimal dose in a clinical setting. Cite this article: Bone Joint Res 2024;13(3):91–100

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

Aim. The induced membrane technique (IMT) or Masquelet technique is a two-step surgical procedure used to treat bony defects (traumatic or resulting from tumoral resections) and pseudo arthroses, even caused by infections. The relatively small case series reported, sometimes with variants to the original technique, make it difficult to assess the real value of the technique. Aim of this study was then to undertake a systematic review of the literature with a particular focus on bone union, infection eradication and complication rates. Method. A systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Individual Patient Data (PRISMA-IPD) guidelines. PubMed and other medical databases were searched using “Masquelet technique” and “induced membrane technique” keywords. English, French or Italian written articles were included if dealing with IMT employed to long bones in adults and reporting at least 5 cases with a 12 months minimum follow-up. Clinical and bone defect features, aetiology, surgical data, complications, re-interventions, union and infection eradication rates were recorded into a database. Fischer's exact test and unpaired t-test were used for the statistical analysis on the individual patient's data. Results. Ten papers met the inclusion criteria (312 patients), but only 5 reported individual patients data (65 cases). IMT was used for acute bone loss (53%), septic (47%) and aseptic (7%) pseudo arthroses and tumour resections (2%). Bone defect length ranged from 0.6 to 26 cm. Overall, union rate was achieved in 88% of the cases and infection cured in 93%. Complication rate was 53%. Surgical variants included the use of antibiotic-loaded spacers (59.9%), internal fixation during the first step (62.1%), use of Reamer-Irrigator-Aspirator technique (40.1%) instead of iliac crest (63.1%) grafting, bone substitutes (18.3%) and growth factors addition (41%). No statistical differences were found comparing patient-related factors or surgical variants in achieving the two outcomes. Conclusions. IMT is effective to achieve bone union and infection eradication, but is associated with a high rate of complications and re-interventions. This should be taken into consideration by the surgeons and be a part of the informed consent. This systematic review was limited by the few studies meeting the inclusion criteria and their high variability in data reporting, making a meta-analysis impossible to undertake. Further studies are needed to demonstrate the role the patients’ clinical features and IMT variants with respect to bone union and infection eradication

Background. Chronic osteomyelitis with intramedullary sequestrum resulting in persistent infection is a challenging orthopaedic problem that often involves multiple surgical operations and unfortunately has a significant recurrence rate. Reasons for this may include difficulty in eradicating all intramedullary microsequestra making subsequent prolonged antibiotic therapy less effective. Use of the Reamer-Irrigator-Aspirator (RIA) has many advantages for management of intramedullary infections in chronic osteomyelitis. The RIA technique allows irrigation of sterile large quantities of saline with simultaneous bony debridement with very sharp reamers that are specially designed to allow simultaneous fluid aspiration. Purpose. We will illustrate the pearls and pitfalls associated with the RIA technique, based on our experience so far. Method. We retrospectively reviewed a number of 6 (six) patients with chronic osteomyelitis of tibia (n=2) and femur (n=4). In an average follow up of 9.6 months post treatment (range 3–18 months) using a protocol including treatment with RIA we noticed immediate control of infection. Complications. Include pin tract infection, pin site pain and fungal infection (due to prolonged use of antibiotics). Conclusion. Based on our patient series so far, the encouraging results we have seen with regard to eradication of infection lead us to believe that RIA has a valuable role to play in the treatment of chronic osteomyelitis

Purpose: The objective of this study is to investigate the effects of the Reamer-Irrigator-Aspirator (RIA) on fat embolism outcome, as compared to the standard AO reamer, utilizing physiologic parameters as outcome measures. Methods: All animal procedures were approved by the Animal Care Committee. Fifteen animal experiments were completed. Following anesthesia, each pig was intubated and ventilated. Initial blood samples were analyzed for proper ventilation and acceptable baseline conditions (PaCO2 between 35–40 mm Hg). One third of the pig’s blood volume was withdrawn to simulate hemorrhagic shock. Each animal was kept in a state of hypovolemia for an hour before transfusion and resuscitation. Each pig underwent alternate assignment into either the RIA or AO group. The distal femur was exposed and reamed in a retrograde fashion, followed by cement pressurization with methylmethacrylate. Physiologic measurements included mean arterial pressure (MAP), pulmonary arterial pressure (PAP), partial pressure of arterial oxygen (PaO2), and cardiac output. Upon completion, the animals were euthanized. The data was analyzed using the SPSS statistical program. Results: One animal in the AO group expired after cement pressurization associated with profound hypotension, pulmonary hypertension and eventual cardiac arrest. There was a statistically significant difference for PaO2 (P = 0.004), cardiac output (P = 0.002), and PAP (P = 0.005) between the AO and RIA groups. That is, by the completion of the experiment the RIA group had higher PaO2, lower PAP, and higher cardiac output measurements as compared to the AO group. There was no statistical significance between the two groups with respect to MAP (P = 0.468). Conclusions: Using established physiologic parameters, there appears to be a difference between the standard AO reamer and the RIA in terms of fat embolism outcome. The RIA showed a more favorable outcome with respect to PAP, PaO2, and cardiac output. With its simultaneous irrigation and aspiration, the RIA may result in less intramedullary fat displacement into the systemic circulation

Aims

The purpose of this study was to: review the efficacy of the induced membrane technique (IMT), also known as the Masquelet technique; and investigate the relationship between patient factors and technique variations on the outcomes of the IMT.

Aims

Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

The August 2014 Foot & Ankle Roundup360 looks at: calcaneotibial nail in ankle fractures; reamer irrigator aspirator for ankle fusion; periprosthetic bone infection; infection in ankle fixation; cheap and cheerful OK in MTP fusion plates; sliding fibular graft for peroneal tendon pathology and fusion for failed ankle replacement.