Tibial Canal Research Articles

Subtalar joint involvement with tibiotalocalcaneal intramedullary nail arthrodesis

Tibiotalocalcaneal (TTC) fusion with an intramedullary nail (IMN) has been utilized for a myriad of indications in hindfoot and ankle reconstruction. However, some controversies remain on the optimal position of the hindfoot. Previous studies have reported on the potential medialization of the rearfoot during insertion of the IMN, but few studies have examined the potential affect on the subtalar joint. We performed the present cadaveric study in order to assess the involvement of a 12-mm IMN with the posterior facet of the calcaneus. A 3-mm guide wire (for a standard TTC IMN) was inserted in an anterograde fashion beginning within the central aspect of the tibial canal in 10 fresh-frozen below knee cadaver specimens. The subtalar joint of each specimen was exposed and images of the posterior facet were collected. Utilizing an open source Java image processing program (ImageJ/Fiji), we calculated a mean native calcaneal posterior facet of 4.6 cm2 with a post ream surface area of 3.6 cm2, resulting in a mean of 21.4% of the posterior facet occupied by an IMN in an anterograde fashion. In conclusion, a TTC IMN placed in optimal position within the ankle and tibia is likely to occupy, on average, a fifth of the calcaneal posterior facet. Though this does leave some possibility of a medial shift of the rearfoot complex, care must be taken to not violate the lateral calcaneal or talar wall. Level of clinical evidence5

Salvage of a comminuted proximal tibial polymicrobial infected non-union with antibiotic loaded bio-composite and intramedullary nailing: a case report

Background. Management of open proximal metaphyseal fractures poses a significant challenge and is fraught with complications. These injuries are severe, often accompanied by extensive soft tissue and vascular damage, leading to high risks of infection and long-term disability. Case presentation. A 72-year-old male was severely injured in a road traffic accident. Plain X-rays and CT angiogram identified a comminuted proximal tibial fracture with transection of the popliteal artery and vein. Initial emergency treatment included fasciotomies, external fixation, and vascular primary repair. On the 12th day of admission, the patient underwent open reduction and internal fixation (ORIF) with dual plate fixation using a two incision technique. A plastic surgeon performed skin grafting, harvested from the patient’s thigh, to allow closure of his fasciotomy wounds immediately following ORIF. Four weeks post-operatively, the patient developed a wound breakdown over the lateral fasciotomy site, exposing the metal plates with a small defect developing on the medial fasciotomy wound in tandem. The patient’s course was further complicated by persistent polymicrobial infections. Over 6 months of antibiotic regimes, operative intervention was ultimately required. All of the infected metal implants were removed, the non-union sites were aggressively debrided. The tibial canal was reamed to prepare for a tibial nailing. An antibiotic loaded bio-composite was then inserted through the non-union sites into the canal followed by an intramedullary nail. A blocking screw was used to address the procurvatum deformity in the sagittal plane. The patient currently shows signs of recovery, mobilizing over short distances, weight-bearing with assistive aids and with healing wounds and early signs of callus formation on recent CT scans and plain X-rays. Conclusions. The management of complex tibial fractures with vascular involvement demands an aggressive multidisciplinary approach and continuous adaptability in treatment plans to address the evolving challenges of such severe injuries. This case exemplifies the utility of injectable antibiotic-loaded bio-composites in a limb-salvage setting and their ability to provide high doses of local antibiotics to an infection site which, in conjunction with appropriate stable fixation and systemic antibiotics, can aid in eradicating and treating fracture-related infections.

Modified Anatomical Anterior Cruciate Ligament Reconstruction with Flat Semitendinosus Graft and C-shaped Tibial Canal

Every year, approximately 400,000 patients undergo anterior cruciate ligament (ACL) reconstruction surgery in the United States, accounting for almost 50% of all knee surgeries in the country. Recent studies have demonstrated that the ACL is a ribbon-like structure with a C-shaped tibial insertion and a flat femoral origin. This article introduces a modification of an ACL reconstruction technique. The modification renders the procedure easily reproducible with standard surgical instruments. We will describe a surgical technique modification that goes beyond the standard round bone tunnels and adopts a more anatomical approach using a C-shaped tibial canal and a flat femoral canal using a flat semitendinosus (semi-T) graft. The use of a semi-T graft better reproduces the ribbon-like ACL anatomy. The semi-T graft, a flat femoral canal, and a C-shaped tibial canal provide increased bone-tendon contact surface area and decreased diffusion length, resulting in improved tendon-bone healing. The modification proposed by our team makes the anatomical ribbon-like ACL graft, C-shaped tibial canal, and the flat femoral canal technique feasible in every orthopaedic operating room and mitigates costly specialized instrument.

Does medullary diameter to stem width ratio and stem length affect outcomes of revision total knee arthroplasties? A case series.

This study aimed to investigate the relationship between the ratio of stem size to intramedullary canal diameter, stem length, and functional outcome in revision total knee arthroplasty (RTKA) procedures, which remains largely unexplored in the current literature. A single surgeon series of RTKA procedures performed between October 2014 and November 2022 were included in this case series, and data were analyzed retrospectively. A total of 32 patients (27 females, 5 males; mean age: 73.2±8.1 years; range, 52 to 88 years) were identified, with a minimum follow-up period of five months and a maximum of eight years. Filtering the patients based on >24 month follow-up, we were left with 13 patients aged between 65 and 88 (mean 74.9±6.9) years. The latest X-rays of patients were analyzed, and the ratio of intramedullary canal diameter to stem width was calculated for both femur and tibia in both anteroposterior and lateral planes. Household income, preoperative C-reactive protein, erythrocyte sedimentation rate, comorbidities, body mass index, and implant dimensions were also recorded. Postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF-12) scores, and range of motion (ROM) measurements were used to evaluate functional outcome. A moderate negative relationship between the tibial canal fill ratio (CFR) in anteroposterior views and ROM of the patients was noted. Additionally, a significant positive correlation was found between SF-12 physical score and CFR in lateral view. A moderate level of correlation between femoral CFR in anteroposterior views was also established. Due to insufficient data, joint ROM data did not show normal distribution. Therefore, a cutoff value indicating the relationship between the stem size and knee ROM could not be calculated using receiver operating characteristic analysis. Multiple regression analysis did not yield significant results, suggesting that hypothesized predictor variables were not sufficient to predict the variation in functional scores. Otherwise, no clear statistical importance or correlation between functional scores, such as WOMAC or SF-12, and CFR was found. In conclusion, the findings suggest that other factors, such as other patient characteristics, surgical techniques, or implant designs, may have a more substantial impact on the functional outcomes in RTKA patients.

Does Fibular Displacement Predict Tibial Malrotation in Simulated Tibia-Fibula Fractures.

Tibial malrotation can occur with medullary nailing of diaphyseal tibial fractures. Fibular alignment has been proposed as a surrogate for axial plane reduction intraoperatively. The purpose of this study was to determine whether fibular alignment is a reliable marker of accurate tibial rotation. Deidentified CT scans of 50 patients with normal tibial anatomy were selected. Using ImageJ software, we simulated osteotomies at three sites (proximal third, mid-diaphysis, and distal third). We overlaid adjacent CT slices and rotated them around the central axis of the tibia in 5° increments of external rotation (ER) and internal rotation (IR). At each increment, measurements of fibular overlap (%) were obtained from anteroposterior (AP) and lateral views. To simulate fixation of the fibula, we repeated rotation around the axis of the fibula with and without a simulated medullary implant in the tibia. A total of 50 patients were included. The mean age was 62 years, average BMI was 25.8, and 28 of 50 patients (56%) were male. Earliest loss of fibular contact occurred at 24° ER and 22° IR at the proximal site. Contact was lost at 26° ER and 28° IR on the AP view and 42° ER and 29° IR on the lateral view. The mean fibular contact at each 5° increment was similar for ER and IR. Fibular contact was reduced to 50% at 10 to 15° of rotation in ER and IR at all sites. Tibial canal contact was lost at 24° in both ER and IR around the fibula. With a virtual medullary implant, the mean maximal rotation was 6°. Surgeons should be aware that 20° or more of malrotation is likely present when fibular contact is lost during medullary nailing of the tibia. Greater than 50% loss of contact should raise suspicion for malrotation. A fixed fibula and medullary tibial implant theoretically preclude significant tibial malrotation.

The efficacy of antibiotic-eluting material in a two-stage model of periprosthetic joint infection.

Periprosthetic joint infections occur in about 2% of patients who undergo primary total joint arthroplasty, a procedure performed over 1 million times in the United States. The gold standard of treatment is a two-stage revision. This study aimed to establish a two-stage procedure in a preclinical small animal model (rat) to test and compare the efficacy of an antibiotic-eluting material in managing infection. Joint replacement was simulated by transchondylarly implanting a polyethylene (PE) plug into the distal femur and a titanium screw in the proximal tibia. Methicillin-sensitive Staphylococcus aureus (MSSA) 108 CFU/mL was injected into the tibial canal and the joint space before wound closure. The control groups were killed on postoperative day (POD) 18 (n = 12) and on POD 42 (n = 4) to assess both early and later-stage outcomes in the control group. The test group underwent revision surgery on POD 18 for treatment using gentamicin-eluting polyethylene (GPE, n = 4) and was observed until POD 42 to evaluate the efficacy of treatment. Our results showed that the bone loss for the treatment group receiving GPE was significantly less than that of the control (p < 0.05), which was supported by the histology images and an AI-tool assisted infection rate evaluation. Gait metrics duty factor imbalance and hindlimb temporal symmetry were significantly different between the treatment and control groups on Day 42. This animal model was feasible for evaluating treatments for peri-prosthetic joint infections (PJI) with a revision surgery and specifically that revision surgery and local antibiotic treatment largely hindered the peri-prosthetic bone loss. Statement of clinical significance: This revision model of peri-prosthetic infection has the potential of comparatively evaluating prophylaxis and treatment strategies and devices. Antibiotic-eluting UHMWPE is devised as at tool in treating PJI while providing weight bearing and joint space preservation.

Alignment and Fixation in Revision Total Knee Arthroplasty With Press-Fit, Offset, Diaphyseal-Engaging Stem Extensions, and Eccentric Reaming Technique

BackgroundA revision total knee arthroplasty must control limb alignment, often to address the cause of failure. Press-fit stems that engage the diaphysis with cement restricted to the metaphysis constitute one fixation technique. These long stems restrict coronal alignment of the prosthesis and as a result reduce the likelihood of extreme malposition. For the same reasons, long stems can make it difficult to manipulate alignment and achieve a specific coronal alignment angle. Nevertheless, femoral stems with a tight diaphyseal fit may still occupy a small range of varus-valgus positions due to the conical distal femoral metaphysis. Pulling the reamer toward the lateral endosteum increases femoral component coronal alignment toward a valgus direction and pushing the reamer medially increases alignment in a more varus direction. A straight stem, in combination with a medially directed reaming, would result in a femoral component that overhangs medially, but an offset stem can recenter the femoral component and maintain the desired alignment. We hypothesized that diaphyseal fit plus this reaming technique can control limb coronal alignment and provide fixation. MethodsThis was a retrospective clinical and long-leg radiographic study of consecutive revision total knee arthroplasties with minimum 2-year follow-up. Outcomes were correlated with New Zealand Joint Registry data to identify rerevisions of 111 consecutive revision knee arthroplasties, 92 after exclusions, at a minimum 2-year (range, 2 to 10) follow-up. ResultsMean femoral and tibial canal fill exceeded 91% on antero-posterior and lateral radiographs. The mean hip-knee-ankle angle was 179.6o (174.9-184.0) with 80% within ± 3o of neutral. The hip-ankle axis crossed the central Kennedy zone in 76.5% of cases and the other 24.6% crossed the inner medial and inner lateral zones. Tibial components: 99.0% ± 3o. Femoral components: 89.5% within ± 3o. There were 5 knees that failed due to infection, 3 from femoral loosening, and 1 due to recurvatum instability from polio. ConclusionsThis study describes a surgical plan and technique for achieving target coronal alignment with press-fit diaphyseal fixation. It is the only series of revision knee arthroplasties with diaphyseal press-fit stems to report canal fill in 2 planes and coronal alignment on full-length radiographs.

High Rate of Intramedullary Canal Culture Positivity in Total Knee Arthroplasty Resection for Prosthetic Joint Infection

BackgroundPeriprosthetic infection is a devastating complication following total knee arthroplasty. A 2-stage protocol often includes an interim antibiotic spacer with intramedullary (IM) dowels. However, the necessity of IM dowels has recently been challenged. Specifically, the data supporting bacterial colonization of the IM canal are limited and controversial. The purpose of this study was to identify the rate of positive IM cultures during resection arthroplasty in periprosthetic knee infection. MethodsA total of 66 IM diaphyseal cultures were taken during resection arthroplasty from 34 patients diagnosed with periprosthetic knee infection. These IM cultures were taken from the femoral and tibial canals using separate sterile instruments. All patients had infected primary total knee arthroplasty implants at the time of resection. ResultsThirty one percent (n = 21) of IM canal cultures in this study were positive from either the tibial or the femoral diaphysis at the time of resection arthroplasty. There were 18 of 21 (86%) of the positive IM canal cultures with concordant intraoperative joint cultures where the IM cultures matched the intraarticular cultures. ConclusionWith a 31% positive IM canal culture rate, this study confirms the logic of using IM dowels with an antibiotic spacer to treat periprosthetic knee infection. Since the failure of a 2-stage reimplantation is catastrophic, any attempt to provide additional local antibiotic delivery seems warranted. Since nearly one-third of our patients had positive IM cultures, this simple addition to an antibiotic spacer has the potential to improve 2-stage results. Claims supporting the elimination of IM dowels during resection arthroplasty seem ill-advised.

The local application of a calcium sulfate bone graft substitute with antibiotics for the treatment of infection after anterior cruciate ligament reconstruction. The results of 3 cases and a literature review

Introduction. We report the results of revision surgery in recurrent infection after anterior cruciate ligament reconstruction (ACLR) consisting of graft canal debridement and the local application of a calcium sulfate bone substitute (CSBS) with the addition of gentamicin and vancomycin in graft canal and infected foci. Materials and methods. Three patients (3 knees) were operated due to a chronic and unsuccessfully treated knee infection after ACLR. Two patients underwent multiple previous revisions (4 and 9, respectively). In all cases, the tibial ACL graft canal and adjacent bone foci were debrided. Post debridement defects in the femur and tibia and the graft tunnel in the tibia were filled with CSBS with an addition of gentamicin and vancomycin. If the absence of the ACL graft was stated, the tibial canal was closed from the joint side with a collagen sponge with gentamicin. Results. After a follow-up of 20 to 26 months, all patients obtained a complete resolution of inflammation and CRP normalization. No side effects related to CSBS were observed. There was no deterioration in the knee function and stability compared to the pre-revision status. Conclusions. CSBS with the addition of gentamicin and vancomycin applied in the graft canal and inflammatory foci in the surrounding cancellous bone proved to be effective and unrelated to complications in chronic infection after ACLR. Level of Evidence: IV (case series).

Personalizing Revision Tibial Baseplate Position and Stem Trajectory With Custom Implants Using 3D Modeling to Optimize Press-fit Stem Placement.

BackgroundA common tibial construct for revision total knee arthroplasty includes a long diaphyseal engaging press-fit stem. Due to tibial canal bowing, compromises are often necessary to match patient anatomy when choosing stemmed implants. The objective of this study is to determine through 3-D modeling whether current implant press-fit options appropriately fit patient anatomy, or whether an alternative angle between the stem and baseplate could increase the cortical engagement of long press-fit tibial stems.MethodsPreoperative computerized tomography scans from 100 patients undergoing TKA were imported into an image-processing software program. Three-dimensional models were created with tibial stems placed at a fixed perpendicular angle and a custom angle to the revision tibial baseplate. Stem diameter, depth, offset, and contact surface area were measured and analyzed between the 2 groups.ResultsSignificantly more cortical contact, larger stem diameter, and smaller offset of the custom keel from the center of the baseplate were associated with free custom tibial stem placement vs a fixed perpendicular baseplate-stem interface (P < .001). Statistically significant differences were also found between different patient demographics.ConclusionsCustom free-angle stem placement allows for increased stem diameter and cortical contact of press-fit tibial stems compared to existing constructs that must interface with the baseplate at a 90-degree angle. Current revision tibia implants limit fixation of tibial press-fit stems and often mismatch with patient anatomy. Alternative ways to fit patient anatomy may be beneficial for patients with extreme mismatch. In the future, custom keel angles may help to resolve this problem.

An Antibiotic-Loaded Hydrogel Demonstrates Efficacy as Prophylaxis and Treatment in a Large Animal Model of Orthopaedic Device-Related Infection.

Local antibiotic therapy is increasingly being recognised for its role in preventing and treating orthopaedic device-related infection (ODRI). A bioresorbable, injectable gentamicin-loaded hydrogel has been developed to deliver local antibiotics at the time of surgery with potential for both prevention and treatment of ODRI. In a prophylaxis model, the antibiotic hydrogel was compared with systemic perioperative antibiotic prophylaxis alone in twelve sheep (six per group) at the time of intramedullary (IM) nail insertion to the tibia, which was inoculated with methicillin-sensitive Staphylococcus aureus (MSSA). In a treatment model of single-stage revision surgery, adjunctive antibiotic-loaded hydrogel was compared with systemic antibiotics alone in a single stage revision of MSSA infection associated with a tibia intramedullary nail in eleven sheep (five/six per group). The primary endpoint was quantitative microbiological results of soft tissue, bone and sonicate fluid from explanted hardware at the time of euthanasia. At euthanasia, the control sheep that received no local antibiotics in the prophylaxis model were all culture-positive (median 1x108, range 7x106-3x108 colony forming units, CFU) while only two of six sheep receiving local gentamicin had any culture positive biopsies (median 1x101, range 0 - 1x105 CFU). For the treatment model, sheep receiving only systemic antibiotics were all culture-positive (median 8x105, range 2x103- 9x106 CFU) while only two of six sheep treated with gentamicin-loaded hydrogel had any culture positive biopsies (median 3x102, range 0 - 7x104 CFU). Local gentamicin concentrations measured in extracellular fluid in the tibial canal show a burst release of gentamicin from the hydrogel. Serum gentamicin concentrations peaked in both models at one day post application and were below detection limit thereafter. This study has demonstrated the effective use of a locally delivered antibiotic hydrogel for both the prevention and treatment of ODRI that is superior to that of systemic antibiotics alone. Future studies will endeavour to translate from preclinical to clinical research trials.

The Clinical Efficacy and Risk Factors after Revision and Reconstruction of Anterior Cruciate Ligament.

The aim of this study was to study the clinical efficacy and prognostic factors after revision and reconstruction of anterior cruciate ligament. All the patients who underwent the first revision of anterior cruciate ligament (ACL) reconstruction in the department of sports medicine from January 2001 to December 2015 were collected. The demographic information, the first revision and reconstruction information of ACL, and the information during the first ACL reconstruction were collected. A total of 335 cases were included. Lysholm score, Tegner activity score, and IKDC subjective score at the last follow-up were significantly higher than those before operation. Compared with graft failure caused by sports injury, the postoperative scores of patients with revision due to life accidents or initial reconstruction techniques were significantly lower (P < 0.05). The postoperative Lysholm score of patients with femoral canal drilling through the tibial canal was lower than that of patients with anterior internal approach. The postoperative IKDC score of patients who underwent medial meniscus suture at the same time was higher than that of patients without meniscus combined injury. ACL revision can improve the stability and function of knee joint. Compared with the revision caused by life accident or technical reasons of primary reconstruction surgery, the patients with graft failure caused by sports injury have better postoperative recovery. Medial meniscus suture and anterior internal approach drilling of the femoral bone canal have a statistically protective effect on the clinical function after ACL revision.

Application of CT Medical Imaging Combined with Deep Learning 3D Reconstruction in the Diagnosis and Rehabilitation of Anterior Cruciate Ligament Injury in Table Tennis Players.

Because of the intense competition, table tennis requires players to bear a strong physiological load, which increases the risk of sports injury. Anterior cruciate ligament (ACL) is an important structure of the knee joint to maintain forward stability and rotational stability and is also a common sports injury in table tennis players. ACL has poor self-repair ability after injury. Therefore, the purpose of this study is to provide a more comprehensive, reliable, and representative theoretical basis for the diagnosis and rehabilitation of anterior cruciate ligament injury in table tennis players, and three-dimensional reconstruction of ACL using dual-source computed tomography (DSCT) combined with deep learning was conducted. For this purpose, a number of table tennis players with ACL injuries were collected, and each patient underwent arthroscopic anterior cruciate ligament reconstruction. DSCT scanning was performed on several knee joints, the 3D model of the knee joint was reconstructed using a CT image postprocessing workstation, and the medial wall of the femoral lateral condyle was reconstructed, as well as the reconstructed single tract of bony canal, tibial plateau, and bony canal. Then, the Lysholm score was used to score the cases, with scores greater than 75 as the excellent group and below 75 as the poor group. The relative positions of the central points of the femoral and tibial canals were marked and measured. The results were as follows: 3D-CT reconstruction could clearly reflect the situation after anterior cruciate ligament reconstruction. In clinic, it is used to evaluate the relationship between bone tunnel location and graft shape so as to guide the surgeon to improve the operation.

Assessment of the primary stability of revision tibial trays augmented with a cementless sleeve in AORI Type III defects

BackgroundPrevious studies have evaluated the initial stability of uncemented tibial components in revision total knee replacement (rTKR) in the presence of an Anderson Orthopaedic Research Institute (AORI) Type II tibial defect. This study sought to evaluate similar metrics in the severe Type III (AORI TIII) defects with combined uncemented stem and sleeve fixation, specifically, the effect of varying the stem’s length and tibial canal engagement upon stability and bone strain. MethodFinite element models generated from the CT scans of 4 tibias with Type III defects were used to investigate the primary stability, in terms of the bone–implant composite peak micromotion (CPM) and microstrains (CPS), achieved after virtual implantations with and without stems. ResultsA stemless rTKR had increased metaphyseal CPM and CPS compared to all stemmed implants. Significant area of the bone supporting the stemless rTKR had CPS greater than bone yield (7000 με). Short engaging stems (≤150 mm construct length), could not achieve reliable engagement in the diaphysis (canal fill ≤ 50%), leading to insufficient reduction of CPS (≥5000 με). Longer engaging stems (170–220 mm construct length), were able to reliably engage the diaphysis (fill ratio ≥ 75%) resulting in CPS ≤ 5000 με. Although, non-engaging stems resulted in increased CPM and CPS compared to engaging stems, long non-engaging stems (170–220 mm construct) appeared to provide additional stability to the rTKR compared to stemless rTKR. ConclusionThe results indicate a likely correlation between uncemented stem engagement and metaphyseal CPS in Type III defects. Excessive strain within the supporting metaphyseal bone is likely to lead to rTKR migration and loosening.

MRI analysis of ACL tendon graft Intracanal Incorporation with polypropylene mesh implantation

Hamstring tendon graft remains one of the most popular for ACL reconstruction (ACLR). However, its disadvantage is long term ligamentation process and intracanal incorporation and delayed rehabilitation. One of the methods for stimulation of connective tissue growth is the implantation of polypropylene mesh (PPM), which are widely used in hernioplasty. Objective. To compare the MRI data dynamics of intracanal incorporation of tendon graft with implantation of PPM in bone canals. Methods. For evaluation of graft reconstruction in the femoral and tibial canals we used criteria based on the analysis of MRI images in PD FS and STIR sequences: the nature of the signal from the graft in the center of bone canal; general view of the graft; the nature of the MRI signal from the tissues around the graft on the tendons-bone border; the pre­sence of synovial fluid in the canals and bone edema around them. Results of MRI of 75 patients who underwent «all-inside» ACLR with semitendinosus graft were analyzed. In the study group (40 patients) were compared to control group (35 patients) additionally implanted PPM around the ends of the tendon graft. Results. Intracanal graft incorporation in the group of patients with implantation of PPM occurred faster. The nature of the signal from the center of the bone canal and on the bone-tendon border progressed significantly faster in all observed terms. In the research group there was not presence of synovial fluid in the canals along the graft. Conclusions. Implantation of PPM around the ends of the ACL tendon autograft immersed in bone canals, leads, according to MRI data, to faster intra-canal incorporation. Key words. Knee joint, anterior cruciate ligament, arthroscopy.

Antimicrobial Silver Multilayer Coating for Prevention of Bacterial Colonization of Orthopedic Implants.

Due to increasing rates of periprosthetic joint infections (PJI), new approaches are needed to minimize the infection risk. The first goal of this study was to modify a well-established infection model to test surface-active antimicrobial systems. The second goal was to evaluate the antimicrobial activity of a silver multilayer (SML) coating. In vitro tests with SML items showed a >4 Log reduction in a proliferation assay and a 2.2 Log reduction in an agar immersion test (7 d). In the in vivo model blank and SML coated K-wires were seeded with ~2 × 104 CFU of a methicillin-sensitive Staphylococcus epidermidis (MSSE) and inserted into the intramedullary tibial canal of rabbits. After 7 days, the animals were sacrificed and a clinical, microbiological and histological analysis was performed. Microbiology showed a 1.6 Log pathogen reduction on the surface of SML items (p = 0.022) and in loosely attached tissue (p = 0.012). In the SML group 7 of 12 SML items were completely free of pathogens (cure rate = 58%, p = 0.002), while only 1 of 12 blank items were free of pathogens (cure rate = 8%, p = 0.110). No silver was detected in the blood or urine of the SML treated animals and only scarcely in the liver or adjacent lymph nodes. In summary, an in vivo infection model to test implants with bacterial pre-incubation was established and the antimicrobial activity of the SML coating was successfully proven.

Upregulation of lncRNA-NONRATT021203.2 in the dorsal root ganglion contributes to cancer-induced pain via CXCL9 in rats

Cancer-induced pain (CIP) is a kind of chronic pain that occurs during cancer progression over time. However, the mechanisms are largely unknown, and clinical treatment remains challenging. LncRNAs have been reported to play critical roles in various biological processes, including chronic pain. The aim of our study was to investigate whether lncRNAs participate in the development of CIP by regulating the expression levels of some molecules related to pain modulation. The CIP model was established by injecting Walker 256 mammary gland tumor cells into the tibial canal of rats. In this study, we found that lncRNA-NONRATT021203.2 was increased in the CIP rats and that lncRNA-NONRATT021203.2-siRNA could relieve hyperalgesia in these rats. For elucidation of the underlying mechanism, we showed that lncRNA-NONRATT021203.2 could target C-X-C motif chemokine ligand 9 (CXCL9), which was increased in the CIP rats, and that CXCL9-siRNA could relieve hyperalgesia. At the same time, silencing lncRNA-NONRATT021203.2 expression decreased the mRNA and protein levels of CXCL9. Immunofluorescence analysis showed that CXCL9 was mainly expressed in the CGRP-positive and IB4-positive DRG neurons. Further research showed that lncRNA-NONRATT021203.2 and CXCL9 were colocalized in the DRG neurons. Our data suggested that lncRNA-NONRATT021203.2 participated in the CIP in rats and likely mediates the upregulation of CXCL9. The present study provided us with a new potential target for the clinical treatment of cancer-induced pain.

Efficacy of NEMO-binding domain peptide used to treat experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus: an in-vivo study

PurposeTreatment of chronic osteomyelitis (bone infection) remains a clinical challenge. Our previous study had demonstrated that NEMO-binding domain (NBD) peptide effectively ameliorates the inhibition of osteoblast differentiation by TNF-α in vitro. In this work, NBD peptide was evaluated in vivo for treating chronic osteomyelitis induced by methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit model.MethodsTibial osteomyelitis was induced in 50 New Zealand white rabbits by tibial canal inoculation of MRSA strain. After 3 weeks, 45 rabbits with osteomyelitis were randomly divided into four groups that correspondingly received the following interventions: 1) Control group (9 rabbits, no treatment); 2) Van group (12 rabbits, debridement and parenteral treatment with vancomycin); 3) NBD + Van group (12 rabbits, debridement and local NBD peptide injection, plus parenteral treatment with vancomycin); 4) NBD group (12 rabbits, debridement and local NBD peptide injection). Blood samples were collected weekly for the measurement of leucocyte count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels. The rabbits in all four groups were sacrificed 6 weeks after debridement; the anti-infective efficacy was evaluated by radiological, histological, and microbiological examination, and promotion of bone remodeling was quantified by micro-CT using the newly formed bone.ResultsExcept two rabbits in the Control group and one in the NBD group that died from severe infection before the end point, the remaining 42 animals (7, 12, 12, 11 in the Control, Van, NBD + Van, and NBD group respectively) were sacrificed 6 weeks after debridement. In general, there was no significant difference in the leucocyte count, and ESR and CRP levels, although there were fluctuations throughout the follow-up period after debridement. MRSA was still detectable in bone tissue samples of all animals. Interestingly, treatment with NBD peptide plus vancomycin significantly reduced radiological and histological severity scores compared to that in other groups. The best therapeutic efficacy in bone defect repair was observed in the NBD peptide + Van group.ConclusionsIn a model of osteomyelitis induced by MRSA, despite the failure in demonstrating antibacterial effectiveness of NBD peptide in vivo, the results suggest antibiotics in conjunction with NBD peptide to possibly have promising therapeutic potential in osteomyelitis.

Patient-Reported Outcomes with Tibial Baseplate Position and PCL Status in Conforming Total Knee Arthroplast

Background and Hypothesis: Anteroposterior (AP) tibial baseplate position, posterior tibial slope, and posterior cruciate ligament (PCL) status in total knee arthroplasty (TKA) undoubtedly affect kinematic patterns. Further, few studies document patient-reported outcome measures (PROMS) in conforming polyethylene TKA with these varying parameters. The purpose of this study was to correlate PROMS with the interaction of AP tibial baseplate position, tibial slope, and PCL status in a consecutive series of primary TKAs with conforming polyethylene. We hypothesized that pain, function, and satisfaction may correlate with a combination of these three parameters. Experimental Design or Project Methods: 589 consecutive primary TKAs of a single implant design performed by a single surgeon between January 2016 and October 2018 were retrospectively reviewed. AP tibial baseplate position (relative to the middle of the tibial canal) and posterior tibial slope measurements were performed on 4-week postoperative sagittal view radiographs with a standardized measurement protocol by two independent blinded raters. Validated PROMS related to activity level, pain, and function were evaluated at minimum one-year. Results: Analyses indicated differences based on ≥8mm vs. &lt;8mm of posterior distance of the tibial baseplate from the tibial canal and whether or not the PCL was released. Four analysis groups (PCL-preserved &lt;8mm, PCL-preserved ≥8mm, PCL-resected &lt;8mm, and PCL-resected ≥8mm) did not differ by demographics/covariates (p≥0.150), tibial slope (p≥0.132), or preoperative PROMS (p≥0.088). The PCL-released &lt;8mm group achieved clinically meaningful higher absolute (92.0) and delta (42.0) median KOOS Jr. scores, higher satisfaction (96.3%), and the greatest reduction in pain while climbing stairs (-7.0) although some findings lacked statistical significance. Conclusion and Potential Impact: In conforming polyethylene TKAs, releasing the PCL in combination with AP tibial baseplate placement &lt;8mm from the tibial canal may eliminate kinematic conflict between the PCL and tibial baseplate leading to improved satisfaction, function, and pain while climbing stairs.

Bone Formation and Adaptive Morphology of the Anterior Tibial Muscle in 3-mm Daily Lengthening Using High-Fractional Automated Distraction and Osteosynthesis with the Ilizarov Apparatus Combined with Intramedullary Hydroxyapatite-Coated Wire.

Purpose We studied osteogenesis and morphofunctional features of the anterior tibial muscle using 3-mm high-frequency automated lengthening with the Ilizarov apparatus alone and in combination with intramedullary nailing. Material and Methods Tibia was lengthened with a round-the-clock automated distractor at a 3-mm daily rate for 10 days in 16 mongrel dogs. In group 1 (n = 8), a 1.8-mm intramedullary titanium wire coated with hydroxyapatite was introduced into the tibial canal followed by Ilizarov frame mounting and transverse osteotomy of the diaphysis. Distraction mode was 0.025 mm x 120 increments a day. In group 2 (n = 8), distraction mode was the same but nailing was not used. Bone formation and the anterior tibial muscle were studied at two time points: (1) upon distraction completion; (2) three months after the apparatus removal. Bone formation was studied radiographically. Muscle preparations were examined histologically and stereomicroscopically. Results There was a threefold reduction in the distraction time in both groups. Consolidation took 13.83±4.02 days in group 1 and 33.7±2.4 days in group 2. Muscle macropreparations of the experimental limb in group 1 at study time points did not show significant differences from intact tissues. Muscle histostructure in both groups was characterized by activation of angiogenesis and myohistogenesis, but the volumetric density of microvessels in the lengthening phase was three times higher in group 1. Conclusion Combined technology significantly reduces the total lengthening procedure and does not compromise limb functions. Intramedullary HA-coated wires promote faster bone formation. The muscle was able to exhibit structural adaptation and plasticity of a restitution type.