Cement Spacer Research Articles

Cement Intercalary Reconstruction After Bone Tumor Resection.

The optimal type of reconstruction after intercalary tumor resection is unclear. Megaprosthetic and biologic reconstructions may restore bone stock, but their complexity may result in complications and delays in rehabilitation and initiation of adjuvant treatment. Instead, cement spacer permanent reconstruction can be performed as index surgery. The authors studied the files of 20 patients who had bone tumors of the humerus and femur and underwent wide margin resection and permanent cement spacer intercalary reconstruction. Mean follow-up was 52 months (range, 2-255 months). The authors evaluated the survival and function of the patients and the outcome of the cement spacer reconstructions. Five patients who had metastatic bone disease died of their disease with their cement spacer reconstruction in place without complications. One patient who had bone sarcoma experienced a local recurrence that was treated with hip disarticulation. Three patients who had bone sarcomas were converted to biologic reconstruction because of disease remission and had improved prognosis without complications related to cement spacer reconstruction. Two patients experienced mechanical failure of femoral reconstruction and underwent revision with an intercalary biologic reconstruction. No patient who had a cement spacer humeral reconstruction experienced a complication, and no patient experienced infection of the reconstruction. Mean Musculoskeletal Tumor Society score of the patients with cement spacer humeral and femoral reconstructions was 85% and 82%, respectively. [Orthopedics. 2021;44(4):e593-e599.].

Antibiotic Cement Spacer and Induced Membrane Bone Grafting in Open Distal End Femur Fractures with Bone Loss; Radiographic and Functional Outcomes: A Retrospective Study

Background: Open fractures are a difficult entity, often complicated by infection and nonunion. Bone loss in such fractures adds to the complexity. Conventional techniques of bone defect management are mainly directed toward fracture union but not against preventing infection or joint stiffness.Objectives: In this study, we evaluated Masquelet's technique for the management of open distal end Femur fractures with bone loss.Methods: Twenty-two patients with open distal end fractures with bone defects who presented within 3 days of trauma from January 2015 to December 2018, treated by the Masquelet's technique are included in this study. All the patients were operated on by the same surgeon. All the patients were taken up for the first stage of surgery immediately after the presentation. Details of the type of injury, location, soft-tissue condition, length of bone defect, type of fixation, the time difference between antibiotic cement spacer placement and bone grafting, and time to the union were documented.Results: Fractures with Type IV bone loss (segmental loss) united slower than fractures having some cortical continuity (Type II and III), P=0.003. In Type IV, the bone loss average time to union was 316.6±44.5 days, whereas, in Type III and II, it was 240±30 and 180, respectively. In the first stage, internal fixation with antibiotics cement spacer was done in all cases. In patients with internal fixation with 2nd stage spacer removal plus bone grafting done, time to union was 244.1±42.9 days. No patients had an infection after the first stage of surgery.Conclusion: The technique of delayed bone grafting after the initial placement of a cement spacer provides a reasonable alternative for the challenging problem of significant bone loss in extremity reconstruction. This technique can be used in either an acute or delayed fashion with equally promising results. The bioactivity of the membrane created by filling large bony defects with cement leads to a favorable environment for bone formation and osseous consolidation of a large void. As this technique becomes more widely applied, the answer to which graft substances to place in the void may become clearer. Increasing clinical evidence will also help support the use of this technique in treating segmental bone loss.

Técnica de Masquelet para defecto óseo en quinto metatarsiano. Reporte de caso clínico

BackgroundThe Masquelet technique is used in the treatment of bone defects in long bones with high success rete reports. It has been described for the treatment of bone loss in the 1st metatarsal and midfoot. The aim of the report is to describe the experience with the technique in a patient with a bone defect of the fourth and fifth metatarsals associated with a transfixing skin defect. Case reportIn a 42-year-old patient who presented a gunshot wound to the lateral column of the right foot with subsequent transfixing coverage defect and bone defect due to comminuted fracture of the fourth and fifth metatarsals. Surgical treatment was performed in 3 stages, the first stabilization and surgical lavage, 2nd stage coverage with a reverse flow sural flap, fixation with a plate and a cement spacer. For a third stage, the bone cement was removed and an autologous cortico-cancellous bone graft was placed. Clinical and radiological follow-up was carried out for 18 months. ResultsThe patient did not present complications including infection, presented anesthesia area in the sural nerve territory, complete viability of the flaps. Normal gait without metatarsalgia was evidenced and in the radiological evaluation it presents graft integration of 90% at described follow up term. Adequate space over the metatarsal cuboid interposition arthroplasty was observed, with a VAS of 1/10 and an AOFAS mid foot score OF 85. DiscussionThere are 7 reports in the literature about the Masquelet technique in the foot, with favorable results, mostly with functional restoration in complex cases in the medial column and no reports on the lateral column. In our case, the technique proves to be a viable alternative, achieving functional and structural restitution of the foot. Evidence levelIV.

Management of surgical site infection post-open reduction and internal fixation for tibial plateau fractures.

AimsIn contrast to operations performed for other fractures, there is a high incidence rate of surgical site infection (SSI) post-open reduction and internal fixation (ORIF) done for tibial plateau fractures (TPFs). This study investigates the effect of induced membrane technique combined with internal fixation for managing SSI in TPF patients who underwent ORIF.MethodsFrom April 2013 to May 2017, 46 consecutive patients with SSI post-ORIF for TPFs were managed in our centre with an induced membrane technique. Of these, 35 patients were included for this study, with data analyzed in a retrospective manner.ResultsAll participants were monitored for a mean of 36 months (24 to 62). None were subjected to amputations. A total of 21 patients underwent two-stage surgeries (Group A), with 14 patients who did not receive second-stage surgery (Group B). Group A did not experience infection recurrence, and no implant or cement spacer loosening was noted in Group B for at least 24 months of follow-up. No significant difference was noted in the Lower Extremity Functional Scale (LEFS) and the Hospital for Special Surgery Knee Score (HSS) between the two groups. The clinical healing time was significantly shorter in Group B (p＜0.001). Those with longer duration of infection had poorer functional status (p＜0.001).ConclusionManagement of SSI post-ORIF for TPF with induced membrane technique combined with internal fixation represents a feasible mode of treatment with satisfactory outcomes in terms of infection control and functional recovery.Cite this article: Bone Joint Res 2021;10(7):380–387.

Sonication fluid culture of antibiotic-loaded bone cement spacer has high accuracy to confirm eradication of infection before reimplantation of new prostheses

BackgroundSonication fluid culture of antibiotic-loaded bone cement spacer has been used to predict reinfection of two-stage revision, but its value remains disputable. This study aims to evaluate the association between the culture result of the sonicated spacer and the status of patients with periprosthetic joint infection receiving two-stage revision.Materials and methodsA comprehensive electronic literature search was performed through four databases including PubMed, Embase/Ovid, and EBSCO, and the Cochrane Library to retrieve studies in which sonication fluid culture of the antibiotic spacer was conducted before reimplantation. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated to assess the association between the culture result of sonicated spacer and prognosis of the two-stage revision.ResultsEleven eligible studies comprising 603 artificial joints with PJI (134 suffering a clinical failure of two-stage revision) were included in the quantitative analysis. The pooled incidences of positive culture of sonicated spacer and intraoperative tissue were 0.14 (95% confidence interval [CI] 0.08–0.21) and 0.14 (95% CI 0.08–0.20), respectively. A positive culture of sonicated antibiotic-loaded bone cement spacer illustrated moderate sensitivity (0.31, 95% CI 0.13–0.58) but high specificity (0.94, 95% CI 0.86–0.98) for the diagnosis of therapeutic failure of two-stage revision; the pooled DOR was 7.67 (95% CI, 3.63–16.22). Meanwhile, the pooled sensitivity, specificity, and DOR of intraoperative tissue culture during the two-stage revision to predict therapeutic failure were 0.32 (95% CI, 0.20–0.47), 0.96 (95% CI, 0.92–0.98), and 10.62 (95% CI, 4.90–23.01), respectively.ConclusionsSonication fluid culture of antibiotic-loaded bone cement spacer revealed high accuracy for confirming eradication of infection before reimplantation of new prostheses and therefore could be used as a supplement for assessing therapeutic effect for PJI. However, both sonication fluid culture and intraoperative tissue culture from antibiotic-loaded bone cement spacer showed restricted yield for the prediction of a septic failure after the two-stage revision of PJI. Large-scale, prospective studies are still needed to testify current findings.

Cement beads and cement spacers: indications, techniques, and clinical results.

To report our experience on the use of antibiotic coated nails (ACN) and cement beads for the management of bone infections. Infected nonunion (INU) cases were classified as: Type I (mild infection with no gap), Type II (moderate with good alignment, severe infection, gap <3 cm, no deformity), Type III (severe infection with gap ≥3 cm, deformity and limb shortening). Treatment involved either the insertion of ACN and cast (Type I), insertion of ACN, beads and external fixator (Type II), or Ilizarov methodology (Type III). A subset of 28 open fractures were admitted with severe contamination or delayed presentation with established infection and treated with debridement, ACN insertion, and antibiotic beads placed in soft tissue dead space areas. Results of 133 cases were classified excellent, good, and poor. Type I INU reported 40 excellent and 22 good results. Type II INU reported 28 (39%) excellent, 30 (43%) good, and 13 (18%) poor results. Poor results were due to uncontrolled infection and knee stiffness. Three patients required knee fusion and 1 required amputation. Fracture union was reported in 68 cases. Four of the 28 Gustilo grade III open fractures treated with ACN developed infected nonunion and had poor function caused by stiff knees. An antibiotic impregnated cement nail (ACN) fills the dead space and elutes high concentrations of antibiotics providing some mechanical stability. We recommend the adjunct use of an ACN for the management of INU cases and for use in select cases of Gustilo grade III open fractures.

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

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

English

BACKGROUND Inadequate marginal fit of fixed restorations leads to plaque accumulation, recurrent caries and periodontal problems. The purpose of this experimental study is to evaluate and compare the marginal fit/gap of computer-aided design and computeraided manufacturing (CAD/CAM) fabricated zirconia copings and zirconia full contoured monolith crowns fabricated on type IV gypsum die having a definite cement spacer thickness of 0.05mm. METHODS This is an in-vitro experimental study carried out from November 2018 to November 2019. A master stainless steel die was used to make 52 type IV die stone models which were randomly divided into 2 groups of 26 samples each. Group 1: zirconia copings and group 2: zirconia monolith full contoured crowns. These restotations were fabricated using CAD/CAM. The marginal gap of each zirconia copings and zirconia full contoured crowns was assessed using scanning electron microscopic analysis on four different pre-marked points (GEMINI SEM 500; ZEISS). Observations were tabulated and analyzed statistically. Independent t-test was used to compare the measurements between zirconia copings &amp; zirconia monolith crowns. RESULTS The least marginal gap observed was for group 2 (zirconia full contoured crown) with a mean value of 29.88 ± 9.16 μm while that of group1 (zirconia coping) was 73.64 ± 28.13 μm. There was a statistically significant difference in the measurements between zirconia copings and zirconia full contoured monolith crowns (P - value &lt; 0.001). There was statistically significant difference in each side of zirconia monolith crowns when compared to the corresponding side of zirconia copings (P - Value &lt; 0.001). CONCLUSIONS CAD/CAM milled full contoured zirconia crowns showed least marginal discrepancy when compared to zirconia copings. All samples had marginal gap within the clinically acceptable range of 120 μm. KEY WORDS Monolith, Zirconia Crowns, Zirconia Copings, Full Contoured Crowns, CAD-CAM

Variability and Interpretation of Synovial Cell Count and Differential: A Perspective in Hip and Knee Arthroplasty.

Multiple threshold values have been proposed for synovial leukocyte count (white blood cell count) and synovial neutrophil percentage (percent polymorphonuclear neutrophils) in the diagnosis of periprosthetic joint infection (PJI). The objective of this study was to elucidate the variability of these criteria under diverse patient/surgical settings. Hip PJIs yield higher synovial white blood cell counts and percent polymorphonuclear neutrophils than knee PJIs. Periprosthetic joint infection of failed unicompartmental knee arthroplasty produces a higher white blood cell count than that of failed total knee arthroplasty. Synovial white blood cell count and percent polymorpho-nuclear neutrophils PJI thresholds also vary in patients with antibiotic cement spacers and depend on the timing from primary arthroplasty (<6 weeks vs >6 weeks). Similarly, test results should be carefully interpreted for patients with comorbidities so that PJI is not missed or falsely identified. [Orthopedics. 2021;44(3):e320-e325.].

Antimicrobial activity of antibiotic loaded cement spacers

Antimicrobial activity of antibiotic loaded cement spacers

Masquelet technique for management of posttraumatic bone defect in a patient of chronic osteomyelitis of long bone

&lt;p class="abstract"&gt;Masquelet technique, which is the use of a temporary cement spacer followed by staged bone grafting, is a treatment strategy for reconstruction of large, infected, bone defects. This paper describes a patient treated with this technique to successfully manage postinfective or posttraumatic osseous long bone defect. Sequestrectomy was done and the injured limb was stabilized and aligned with application of external fixator at the time of initial antibiotic cement spacer placement. After 6 weeks of proper antibiotic coverage, all antibiotics were stopped for next 2 weeks. Clinical evaluation and investigations were done to rule out any residual infection. Osseous consolidation was successfully achieved with staged bone grafting and internal stabilization of long bone defect.&lt;/p&gt;

Validation of new shoulder periprosthetic joint infection criteria

A periprosthetic joint infection (PJI) in the shoulder can be difficult to diagnose. Many variables have been used to determine a PJI. Recently, the 2018 International Consensus Meeting (ICM) on orthopedic infections gave new criteria to help identify PJI in the shoulder. With the new criteria (major and minor), the PJI definition can be categorized into definite, probable, possible, and unlikely. This study was conducted to assess the new criteria for a series of consecutive first stage revision shoulder arthroplasty cases. All patients undergoing a first stage revision shoulder arthroplasty using a prosthesis made of antibiotic-loaded acrylic cement (PROSTALAC) spacer from 2016 through 2019 were evaluated retrospectively. All cases were performed by a single surgeon. Each case was reviewed using the 2018 shoulder ICM diagnostic criteria. Secondary factors evaluated were type of organism identified, accuracy of minor criteria, and frozen vs. permanent section accuracy. A total of 87 first-stage revision arthroplasty cases were reviewed. Based on the 2018 ICM criteria, there were 20 definite (30.0%), 19 probable (21.8%), 6 possible (6.9%), and 42 unlikely (48.3%) infections. Cutibacterium acnes was the most common infectious organism overall (77.3% of culture positive cases) and was present in 39.1% of cases overall. Ten patients (25.6%) grew multiple organisms. Thirty-one patients (35.6%) had a loose humeral stem, with 23 of those patients (74.2%) having a definite or probable infection (odds ratio [OR] 7.2, 95% confidence interval [CI] 2.67-19.37, P = .0001). Eleven patients (91.7%) with an elevated intraoperative synovial neutrophil cell count had a definite or probable infection. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) was elevated in patients with a definite or probable infection (OR 9.4, 95% CI 2.47-35.62, P = .0010, and OR 7.7, 95% CI 2.29-25.56, P = .0009), respectively. Discordant results between frozen and permanent sections were found in 4 patients (4.6%). The 2018 ICM shoulder infection criteria gave a new scoring system to diagnose PJI. C acnes was the most common infectious organism identified. Patients who had a loose humeral stem, elevated ESR, or elevated CRP were more likely to have either a definite or probable PJI. Frozen sections were able to accurately identify definite infections. Unexpected wound drainage and positive preoperative cultures were low-yield criteria in this series. More research into determining periprosthetic shoulder infection is needed to help identify which patients are more likely to have an infection.

Masquelet-Induced Membrane Characteristics in Chicken Radii Bone Defects.

This study evaluated the formation of a Masquelet-induced membrane created through the formation of segmental bone defects in the radii of 15 healthy domestic chickens. When the chickens were in a surgical plane of anesthesia, a 1.5-cm segmental bone defect was produced in the left radius, which was subsequently filled with a bone cement spacer during its pasty polymerization phase. The bone defects were evaluated through radiographic imaging immediately after surgery and at 7, 15, 21, and 30 days after the creation of the bone defect. Five birds were euthanatized at 15, 21, and 30 days postoperatively for histological evaluation of the bone defect site. Immediate postoperative radiographic examination of the radii showed the presence of bone cement, which occupied the segmental bone defect. Thirty days after the surgical procedure, the presence of new bone formation at the fractured extremities was evident in the 5 remaining chickens. Histologically, the induced-membrane had 3 distinct zones at 15 days postoperatively, including 1 cell layer in contact with the bone cement spacer, 1 layer with collagen fibers, and 1 layer in contact with muscle, which was composed of disorganized connective tissue, active fibroblasts, and blood vessels. Twenty-one days after surgery, the zones were less defined, and there were metaplastic areas comprising cartilage and bone. Postoperative, diffuse mineralization of the membrane was observed 30 days after the surgical procedure. Formation of the induced membrane was observed during all periods of evaluation. The best histological characteristics for the Masquelet-induced membrane were detected 15 days after the formation of the bone defect, suggesting this would be the optimal time for second-stage surgery for bone reconstruction.

Renal Toxicity Associated With Resection and Spacer Insertion for Chronic Hip PJI

BackgroundTwo-stage exchange arthroplasty with high-dose antibiotic-loaded bone cement spacer and intravenous (IV) antibiotics is the most common method of managing infected total hip arthroplasties. However, the contemporary incidence, risk factors, and outcomes of acute kidney injuries (AKIs) in this cohort are unknown. MethodsWe identified 227 patients treated with 256 antibiotic-loaded bone cement spacers after resection of an infected primary total hip arthroplasty between 2000 and 2017. Mean age was 65 years, mean body mass index was 30 mg/kg2, 55% were men, and 16% had pre-existing chronic kidney disease (CKD). Spacers were in situ for a mean of 15 weeks, concomitantly associated with IV or oral antibiotics for a mean of 6 weeks. AKI was defined as a creatinine ≥1.5X baseline or ≥0.3 mg/dL. Mean follow-up was 8 years. ResultsAKI occurred in 13 patients without pre-existing CKD (7%) vs 10 patients with CKD (28%; OR 5; P = .0001). None required acute dialysis. Postoperative fluid depletion (β = 0.31; P = .0001), ICU requirement (β = 0.40; P = .0001), and acute atrial fibrillation (β = 0.43; P = .0001) were independent predictors for AKI in patients without pre-existing CKD. Duration of in situ spacer, mean antibiotic dose in cement, use of amphotericin B, and type of IV antibiotics were not significant risk factors. At last follow-up, 8 AKIs progressed to CKD, with one receiving dialysis 7 years later. ConclusionAKIs occurred in 7% of patients with normal renal function, with 5-fold greater risk in those with CKD, and 4% did develop CKD. Importantly, causes of acute renal blood flow impairment were independent predictors for AKI. Level of EvidenceLevel III, comparative study.

Candida Periprosthetic Joint Infection: Is It Curable?

Candida periprosthetic joint infection (CPJI) is a rare and very difficult to treat infection, and high-quality evidence regarding the best management is scarce. Candida spp. adhere to medical devices and grow forming biofilms, which contribute to the persistence and relapse of this infection. Typically, CPJI presents as a chronic infection in a patient with multiple previous surgeries and long courses of antibiotic therapy. In a retrospective series of cases, the surgical approach with higher rates of success consists of a two-stage exchange surgery, but the best antifungal treatment and duration of antifungal treatment are still unclear, and the efficacy of using an antifungal agent-loaded cement spacer is still controversial. Until more evidence is available, focusing on prevention and identifying patients at risk of CPJI seems more than reasonable.

Histological analysis of induced membranes in patients whose bone defects were treated with the Masquelet technique to identify factors affecting the vascularity of induced membranes

BackgroundRich vascularity of the induced membrane (IM) is important for Masquelet reconstruction surgery. The factors affecting IM vascularity are not completely understood. This study aimed to investigate these factors using histological samples of human IMs.MethodsWe retrospectively evaluated 36 patients whose bone defects were treated using the Masquelet technique. Two clinical pathologists analyzed histological sections of IM pieces (1 cm2). The number of blood vessels per 1 mm2 was counted and compared among men and women, femur or tibia, with and without free flap surgery, antibiotic impregnation to the cement, osteogenesis inside the membrane, smoking, and diabetes mellitus. The number of blood vessels within the same patient was compared among different time points. Correlation analysis was performed among blood vessel numbers and patient age, duration of cement spacer placement, and histological grading scales (inflammation, foreign body reaction, and fibrosis).ResultsIM formation with rich vascularity and some inflammation, foreign body reaction, and fibrosis were histologically confirmed in all patients. We found 37.4 ± 19.1 blood vessels per 1 mm2. The number of blood vessels was significantly lower in patients with than in those without free flap surgery; it was higher in patients with osteogenesis inside the IM. No significant correlations were found in any of the analyses.ConclusionSex, patient age, smoking, diabetes mellitus, femur or tibia, duration of cement spacer placement, and antibiotic impregnation to the cement did not affect IM vascularization. IM vascularization was reduced in patients with than in those without free flap surgery.

Two-Stage Primary Arthroplasty in the Infected Native Knee: A Systematic Review and Pooled Analysis.

The knee is the commonest native joint to develop an infection. A two-stage primary knee replacement, with an interim stage of debridement and cement spacer application, modelled after two-stage revision for periprosthetic joint infections (PJI) has been reported for the management of chronic infections. To systematically review the literature to find the infection-free survival and outcomes of this operation and explore its indications. PRISMA guidelines were followed for this review. A systematic search of 4 online databases was conducted on 9/8/2020. After reviewing 226 abstracts and applying our selection criteria, 10 papers were selected for full-text review, and 9 included in the final synthesis. On pooled analysis, an infection-free survival of 95.6% (CI 94.7-96.4) was found at 2years in 139 knees, which was unchanged over the remainder of the follow-up (Mean 3.9years). The complication rate after final implantation was 6% in those that did not develop reinfection. The mean pooled Knee Society Score (KSS) and KSS Function score among 70 patients (4 papers) was 83.4 (80.1-89.0) and 76.8 (71.5-78.0), respectively. The mean range of motion among 82 patients (6 papers) was more than 100°. Two-stage primary knee replacement is a safe, effective and reliable procedure with good results in the short to medium term. Further studies are required to lay down precise indications and cost-effectiveness of this procedure, in comparison to other strategies for chronic infection. All joint registries should develop methods to identify patients undergoing two-stage procedures, to understand their long-term survival and outcomes.

Do Low Hemoglobin Levels Affect the Healing Process of Periprosthetic Joint Infection?

BackgroundRevision knee arthroplasty (RKA) is associated with low hemoglobin (Hb) levels after surgery, which results mostly from perioperative blood loss. Periprosthetic joint infection (PJI) is one of the common reasons for RKA. This study aimed to determine whether low Hb levels affect the healing process of PJI.MethodologyThis retrospective study included 69 patients who underwent two-stage revision for PJI between 2013 and 2016. Patients were divided into two groups according to the latest Hb levels (Hb < 10 and Hb > 10 g/dL) during hospitalization for the first-stage revision surgery. Laboratory parameters of infection were measured during the cement spacer retention period: C-reactive protein (CRP), sedimentation rate (SEDIM), and white blood cell (WBC) count. Treatment was evaluated in two periods: cement spacer retention period (between the first surgery and second surgery) and the first normal CRP period (between the first surgery with the first normal CRP level during the cement spacer retention period). Infection parameters in the two time periods and reoperation with cement spacer were compared between the groups.ResultsThe mean patient age was 67.3 ± 7.94 (50-87) years, and the female-to-male ratio was 4:1. No difference was found in the postoperative first control CRP, SEDIM, and WBC between the groups (p = 0.953, p = 0.3341, and p = 0.444, respectively). CRP-SEDIM control curves were observed in parallel, and no significant difference was found. The cement spacer retention period was 60.3 ± 24.8 (17-123) days, and the first normal CRP period was 87.3 ± 28.4 (14-161) days; no statistical difference was found between the groups (p = 0.727, p = 0.754).ConclusionsIn RKA, as low Hb level was not a negative factor of infection, blood transfusion should be avoided as it has many complications.

Mycobacterial periprosthetic joint infection after primary total knee arthroplasty.

Mycobacterial periprosthetic joint infection (PJI) is very rare and is generally associated with an immunosuppressive environment. Few large-scale studies of this unusual PJI have been conducted. The current study was performed to assess the clinical features and outcomes following two-stage re-implantation for mycobacterial PJI after primary total knee arthroplasty (TKA). We conducted a retrospective review of data collected from our database involving tencases of two-stage re-implantation manifesting mycobacterial PJI. Patients were followed for at least fiveyears or until recurrent infection. The mean follow-up duration in patients who remained free of infection was 7.5 years (range 5-9.5 years). Seven patients (70%) belonged to the American Society of Anesthesiologists' grade 3 or 4. The surgical protocol entailed resection arthroplasty and cement spacer insertion with vigorous debridement, followed by at least sixweeks of systemic antimicrobial therapy and delayed re-implantation in all patients. The median duration from resection arthroplasty to re-implantation was 5.3 months (range 2-10.5 months). Following re-implantation, five patients with Mycobacterium fortuitum were treated with amikacin for sixweeks and oral clarithromycin for threemonths. Five patients infected with M. tuberculosis received anti-tuberculosis medications immediately after pathogen isolation, for a period of 12 months. Mycobacterial PJI can be treated successfully via resection arthroplasty and delayed re-implantation combined with proper antimicrobial agents. Suspicious infection or loosening after primary TKA, particularly in an immunosuppressive environment, warrants the attention of an orthopedic surgeon to consider the possibility of unusual PJI.

Гистоморфометрические изменения синовиальной оболочки коленного сустава при комбинированном применении несвободной костной пластики по Илизарову и технологии Masquelet (экспериментальное исследование)

Relevance Defects of long bones result in anatomical and functional complex of pathologies in the entire limb. There are few fundamental studies of tissues adjacent to bone defects by using different technologies for management of long bone defects. Purpose To study the structural changes in the synovial membrane of the knee joint by modelling the conditions for tibial defect management using the Ilizarov method of non-free bone plasty in combination with the Masquelet technique. Materials and methods The conditions of post-resection defect of the tibia (from 15 % of the segment length) by lengthening the distal fragment were modeled in ten mongrel dogs. Temporarily, for 30 days, a cement spacer was implanted into the post-resection defect gap. Upon its removal, the intermediate fragment in the lower third of the leg was transported at a rate of 1 mm in 4 steps until complete contact of the bone fragments. Histomorphometric studies of the synovium were carried out at the observation stages at the end of the fixation period (60 days) and after removing the apparatus (30 days). Results Two types of changes were revealed in the synovium: changes of a destructive nature without synovitis (30 % of cases) and with signs of synovitis (70 % of cases, 3 dogs had mild synovitis and 4 dogs had severe synovitis). Changes in the microvessels of the synovial membrane in synovitis indicated impaired microcirculation, high activity of angiogenesis and the development of hypervascularization. Conclusion Experimental management of the tibial bone defect by Ilizarov method in combination with the Masquelet technique revealed signs of synovitis of the knee joint in 70 % of cases using histophorphometry methods.