Periprosthetic joint infection (PJI) is a complication of total joint arthroplasty that typically requires revision surgery for treatment. Systemic antibiotics are usually held prior to surgery to improve yield of intraoperative cultures. However, recent studies suggest that preoperative aspirations have a high concordance with intraoperative cultures, which may allow surgeons to initiate antibiotic treatment earlier. The purpose of the study was to investigate the effect of Pre-surgical systemic antibiotic therapy on the bacterial burden within the periprosthetic space and systemic immune reaction. PJI was induced with MSSA (Xen36) S. aureus in the right knee of 16-week old, female, C57BL6 mice using a previously validated murine model. Mice were randomized to three groups (n=8, each): control; Vanc, receiving systemic vancomycin (110mg/kg, SQ, twice daily); or VancRif receiving vancomycin same as in Vanc group, plus rifampin (12mg/kg dose, IV, once daily). Following 2 weeks of treatment, mice were euthanized and periprosthetic bone, soft tissue and the implant were harvested. Bacterial burden, colony forming units (CFUs), was quantified in soft tissue, tibial bone, and on the implant. Specifically, tissues were homogenized and serially plated for CFUs, while the implant was sonicated and then plated for CFUs. The host immune response was analysed through weighing inguinal and iliac lymph nodes and through measuring serum amyloid A (SAA). Non-parametric pairwise group comparisons of the three outcome measures were performed using a Mann-Whitney U test.Aim
Method
Polypropylene (PPE) synthetic mesh is increasingly used in knee arthroplasty surgery to salvage a disrupted extensor mechanism. Despite its clinical success, it is associated with a high rate of periprosthetic joint infection (PJI), which is hypothesized to be caused by bacterial biofilm. The purpose of the current study is to describe the progression of PPE-based biofilm formation over time and to determine if intraoperative antiseptic solutions could be used to effectively remove biofilm when treating PJI. Commercially available knotted monofilament PPE mesh1 was cut into 10mm circular shape, immersed in tryptic soy broth (TSB) with methicillin-sensitive staphylococcus aureus and cultured individually in 48-well plates for 10 days to elucidate the biofilm grown on mesh over time. At every 24 hours, a triplicate of samples was retrieved and biofilm on the mesh was dislodged by sonicating at 52 kHz for 15 minutes and quantified by counting colony-forming units (CFUs) after overnight growth. The biofilm growth was also verified using scanning electron microscopy. The effect of saline and antiseptic solutions was verified by exposing 1) 0.05% chlorohexidine gluconate2, 2) acetic acid-based mixture3, 3) diluted povidone-iodine (0.35%), 4) undiluted povidone-iodine (10%)4, and 5) 1:1 combination of 10% povidone-iodine & 3% hydrogen peroxide on immature and mature biofilms for 3 minutes, created by culturing with bacteria for 24 hours and 72 hours respectively. All experiments were performed in quintuples and repeated. Antiseptic treatments that produced a three-log reduction in CFU counts compared to controls were considered clinically significant.Aim
Method
Prosthetic joint infection (PJI) is a devastating and costly complication of total joint arthroplasty (TJA). Use of extended oral antibiotic prophylaxis (EOAP) has become increasingly popular in the United States following a highly publicized study (Inabathula et al) from a single center demonstrating a significant protective effect (81% reduction) against PJI in ‘high-risk’ patients. However, these results have not been reproduced elsewhere and EOAP use directly conflicts with current antibiotic stewardship efforts. In order to study the role of EOAP in PJI prevention, consensus is needed for what defines ‘high-risk’ patients. The revision TJA (rTJA) population is an appropriate group to study due to having a higher incidence of PJI. The purpose of the current study was to rigorously determine which preoperative conditions described by Inabathula et al. (referred to as Inabathula criteria (IBC)) confer a higher rate of PJI in patients undergoing aseptic rTJA. 2,256 patients that underwent aseptic rTJA at a single high-volume institution between 2016–2022 were retrospectively reviewed. Patient demographics and comorbidities were recorded to determine if they had 1 or more ‘IBC’, a long list of preoperative conditions including autoimmune diseases, active smoking, body mass index (BMI)>35, diabetes mellitus, and chronic kidney disease (CKD). Reoperation for PJI at 90-days and 1-year was recorded. Chi-squared or Fischer's exact tests were calculated to determine the association between preoperative presence/absence of IBC and PJI. Multivariable logistic regressions were conducted to determine if specific comorbidities within the IBC individually conferred an increased PJI risk.Aim
Method
Recently, new metallurgical techniques allowed the creation of 3D metal matrices for cementless acetabular components. Among several different products now available on the market, the Biofoam Dynasty cup (MicroPort Orthopedics® Inc., Arlington, TN, USA) uses an ultraporous Titanium technology but has never been assessed in literature. Coping with this lack of information, our study aims to assess its radiological osteointegration at two years in a primary total hip arthroplasty and compares it to a successful contemporary cementless acetabular cup. This monocentric retrospective study includes 96 Dynasty Biofoam acetabular components implanted between March 2010 and August 2014 with a minimum 2 years radiographic follow-up. Previous acetabular surgery, any septic issue or re-operation for component malposition were exclusion criteria. They were compared to 96 THA using the Trident PSL matched for age, gender, BMI and follow-up. Presence of radiolucencies and sclerotic lines were described on AP pelvis views using the classification of DeLee and Charnley There was no statistical difference between the two groups concerning demographics and mean follow-up (p> 0.05). Shell's anteversion was similar but inclination was greater in the biofoam group (p=0.006). 27,17% of the Biofoam shells presented radiolucencies in 2 zones or more and 0% of the Trident shells. 11,96% of Biofoam cups showed radiolucencies in the 3 zones of DeLee comparing to 0% of the Trident cups. There was no statistical difference between the Biofoam group (n=54/96) and the Trident PSL group (n=57/96) in pre-operative functional scores for both WOMAC subscales and SF-12. When evaluating last follow-up PROM's, no significant differences were found comparing the entirety of both groups, 56 Biofoam and 51 Trident PSL. No difference was found either when comparing Biofoam patients with ³ 2 zones of radiolucencies (n=15) to the whole Trident group (n=51). This study raises concerns about radiologic evidence of osteointegration of the Biofoam acetabular cup. Nevertheless, these radiological findings do not find any clinical correlation considering clinical scores. Thus, it may question the real meaning of these high-rated radiolucencies, which at first sight reflect a poorer osteointegration. The first possible limitation with this study is an overinterpretation of the radiographs. Nevertheless, both observers were blinded regarding the patients groups and clinical outcomes and there was a strong inter-observer reliability. Although both cohorts were matched on their demographics and were similar on the cup anteversion, we noticed a slightly lower abduction angle in the Biofoam population. It could reduce the bone-implant coverage area and hence hinders the bony integration, but this difference was small and both groups remained in the Lewinneck security zone. Furthermore, even if patients were matched on age, gender, BMI and follow-up, other variables can influence early osteointegration (smoke status, osteoporosis) and have not been controlled even though we have no reasons to think their distribution could differ in the 2 groups. The real clinical meaning of these findings remains unknown but serious concerns are raised about the radiographic osteointegration of the Dynasty Biofoam acetabular components. Concerns are all the more lawful that this implants aim to enhance osteointegration.
PJI is a devastating complication following total joint arthroplasty. In this study, we explore the efficacy of a bacteriophage-derived lysin, PlySs2, against
Introduction
Methods
The resultant cup orientation depends upon the orientation of the pelvis at impaction. No studies to date have assessed whether patient-position during total hip arthroplasty (THA) has an effect on cup orientation. This study aims to 1) Determine the difference in pelvic position that occurs between surgery and radiographic, supine, post-operative assessment; 2) Examine how the difference in pelvic position influences subsequent cup orientation and 3) Establish whether pelvic orientation, and thereafter cup orientation, differences exist between THAs performed in the supine versus the lateral decubitus positions. This is a retrospective, multi-surgeon, single-centre, consecutive series. 321 THAs who had intra-operative, post-cup impaction, AP pelvic radiograph, in the operative position were included; 167 were performed with the patient supine (anterior approach), whilst 154 were performed in the lateral decubitus (posterior approach). Cup inclination/anteversion was measured from intra- and post-operative radiographs and the difference (Δ) was determined. Change in pelvic position (tilt, rotation, obliquity) between surgery and post-operatively was calculated from Δinclination/anteversion using the Levenberg-Marquardt algorithm.Introduction
Patients/Materials & Methods
Several studies have shown that functional outcomes are similar regardless of being discharged directly to home or to a rehabilitation center after total knee arthroplasty (TKA). Therefore, we sought to determine if there is a difference in patient care or patient satisfaction for patients discharged to in-patient rehabilitation or home-based rehabilitation. Between February and May of 2015, one hundred and seventy one consecutive patients were prospective identified after undergoing TKA by one of three surgeons. At an average of six-weeks post TKA, all patients were asked a patient administered questionnaire to determine if diagnostic testing (ultrasounds, or x-rays) or blood transfusions were performed during the first-six weeks at either home (n=86) or a rehab (n=85) facility.Introduction
Materials and Methods
Positioning of a femoral sizing guide has been cited as being a critical intraoperative step during measured-resection based TKA as it determines femoral component rotation. Consequently, modern femoral sizing guides permit surgeons to ‘dial in’ external rotation when placing the guide. Although this feature facilitates guide placement, its effect on posterior femoral condylar resection and flexion gap stability is unknown. This study examines the effect of rotation on posterior femoral condylar resection among different posterior-referencing TKA designs. Left-sided posterior-referencing femoral sizing guides and cutting blocks from nine posterior-referencing femoral sizing guides belonging to six TKA manufacturers were collected. Each guide underwent high-resolution photography at a setting of zero, three and greater than three degrees of external rotation. The axis of rotation for each guide was then identified and its location from the posterior condylar axis was recorded (figure). Cutting blocks from each system were then photographed and the amount of posterior condylar resection from the medial and lateral condyles was calculated for each setting of external rotation (figure). The posterior resection was then compared to the standard distal resections for each system.Introduction
Methods
Cementless fixation is the current preferred method for acetabular reconstruction in total hip arthroplasty (THA). Despite promising long-term results among several designs, theoretic concerns regarding the high modulus of elasticity, low friction against bone and low volumetric porosity of contemporary cementless cups have spurred the introduction of novel porous surfaces that are designed to improve osseointegration and decrease aseptic loosening. Although several novel surfaces have been introduced into clinical use over the past decade, very little literature regarding their clinical and radiographic performance exists. The current study investigates the performance of one such novel surface, Tritanium (Stryker, Mahwah, NJ). We prospectively evaluated 121 consecutive THAs performed in 94 patients by a single arthroplasty surgeon using the Tritanium Primary Acetabular Component (Stryker, Mahwah, NJ). 109 hips (90.1%) had adequate clinical and radiological follow-up for analysis. Clinical parameters recorded included implant survivorship, Harris Hip Scores, WOMAC and SF-12. Furthermore, radiographs at the 6-week, 1 year and most recent clinical visit were evaluated by two blinded observers for implant position, evidence of radiolucency, sclerosis and component migration.Introduction
Methods
While implant designs and surgical techniques have improved in total knee arthroplasty (TKA), approximately 20% of patients remain dissatisfied. The purpose of this study was to determine if reproduction of anatomic preoperative measurements correlated to improved clinical outcomes in TKA. We retrospectively reviewed95 patients (106 knees) who underwent a TKA between 2012 −2013 with a minimum of one year follow-up. All patients had a pre and post-operative SF-12 and WOMAC scores. Pre and 6 week post-operative radiographs were reviewed to compare restoration of coronal plane alignment, maintenance of joint line obliquity, and maintenance of tibial varus. Coronal alignment was defined as the angle formed between the mechanical axis of the femur and the the tibia. Joint line obliquity was defined as the angle between the mechanical axis of the limb and the line which best parallels the joint space at the knee. Tibial varus was compared between the preoperative proximal lateral tibial angle and the angle formed by the mechanical axis of the tibia and tibial component postoperatively.Introduction
Methods
Superficial wound complications can occur in up to 10% of total knee arthroplasty (TKA) patients and have been associated with deep infection. The ideal material for TKA closure should fulfill the following requirements: 1) fast intraoperative application, 2) minimal wound complications and discomfort, and 3) can be removed by patients without a home care visit. We present our experience with a novel, non-invasive, removable skin closure system compared to conventional staple closure. We prospectively evaluated 105 consecutive patients who underwent unilateral or bilateral primary TKA and received skin closure consisting of the Zip 16 Surgical Skin Closure System (Zipline) for skin. All procedures were performed a by single surgeon (SBH) using a mini-midvastus approach. All patients were mobilized on the day of surgery and received 2 weeks of Rivaroxaban thromboprophylaxis. Patient demographics, medical comorbidities, in-hospital complications and wound healing and complications during the first 6-week post-operatively were recorded. Data was compared to a previous TKA cohort of 1,001 patients from the same surgeon who received staples for closure and warfarin for thromboprophylaxis.Introduction
Methods
Conservative treatment of minimally displaced distal radius fractures (DFR) remains controversial. Circumferential casting (CC) in the acute setting is believed to supply superior support compared to splinting, but is generally cautioned due to the limited capacity of a cast to accommodate ongoing limb swelling possibly leading to complications. However, there is no conclusive data on which to base these beliefs. Moreover, the appropriate management of cast complications while minimizing risk to fracture integrity remains unclear. This retrospective study of distal radius fractures treated conservatively with circumferential cast in the acute setting aims to: A. Determine demographic, fracture dependant or management risk factors for CC complications. B. Determine the natural history for both patients with CC and those with CC necessitating cast modification. Hospital records and radiographic data of 316 patients with DRFs treated with CC at a tertiary-care university hospital between the years 2006 to 2009 were reviewed. Our primary outcome was to access risk factors for cast complications including swelling, pressure sores, neuropathies and loss of cast immobilization. Our secondary outcome accessed reduction stability in patients undergoing cast re-manipulation.Purpose
Method
Pediatric orthopaedic surgeons encounter referrals from primary care practitioners and pediatricians that are benign in nature or within accepted limitations for physiological musculoskeletal variance. These referrals are believed to be secondary to insufficient pediatric musculoskeletal expertise and consume already limited pediatric orthopaedic resources. To date, our annual CME course dedicated to pediatric musculoskeletal medicine is the only one of its kind in Canada. It includes didactic teaching as well as a clinic of unnecessary referrals in which participants examine patients and receive feedback from consultants. The purpose of this study was to evaluate the impact of a pediatric musculoskeletal CME course on the quality of local outpatient referrals over a four year period. Retrospective chart reviews were performed to evaluate outpatient referrals at a tertiary orthopaedic center over an eight month period prior to the commencement of an annual CME course (2006–2007) and three years following its initiation (2010). 1041 consecutive referrals from the first time period and 1124 consecutive referrals from the second time period were collected. Referrals for normal conditions within physiological tolerance were identified based on the final clinical diagnosis by the consultant orthopaedic surgeon and the scheduled follow up.Purpose
Method
Internal fixation of fractures in the presence of osteopenia has been associated with a failure rate as high as 25%. Enhancing bone formation and osseointegration of orthopaedic hardware is a priority when treating patients with impaired bone regenerative capacity. Fibroblast Growth Factor (FGF) 18 regulates skeletal development and could therefore have applications in implant integration. This study was designed to determine if FGF 18 promotes bone formation and osseointegration in the osteopenic FGFR3−/− mouse and to examine its effect on bone marrow derived mesenchymal stem cells (MSCs). In Vivo: Intramedullary implants were fabricated from 0.4 × 10mm nylon rods coated with 300nm of titanium by physical vapour deposition. Skeletally mature, age matched female FGFR3−/− and wild type mice received bilateral intramedullary femoral implants. Left femurs received an intramedullary injection of 0.1μg of FGF 18 (Merck Serono), and right femurs received saline only. Six weeks later, femurs were harvested, radiographed, scanned by micro CT, and processed for undecalcified for histology. In Vitro: MSCs were harvested from femurs and tibiae of skeletally mature age matched FGFR3−/− and wild type mice. Cells were cultured in Alpha Modified Eagles Medium (αMEM) to monitor proliferation or αMEM supplemented with ascorbic acid and sodium beta-glycerophosphate to monitor differentiation. Proliferation was assessed through cell counts and metabolic activity at days 3, 6 and 9. Differentiation was assessed through staining for osteoblasts and mineral deposition at days 6, 9 and 12.Purpose
Method
Cadeveric studies showed that single bundle ACL reconstructions were successful in limiting anterior tibial translation but were insufficient to control a combined rotatory load of internal and valgus torque. One possible cause of these condition could be that current single bundle procedures cannot realistically reproduce the complex anatomy of the ACL, especially the different function of its anteromedial(AM)and posterolateral(PL)bundle. The hypothesis of our study is that the addition of the PL bundle to the AM bundle, in an “in vivo” double bundle computer assisted ACL reconstruction, is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion. Computer assisted ACL reconstruction has been used because it could be very effective in evaluating the global performance of the reconstructed knee. Ten consecutive doble bundle ACL reconstructions were performed in our Hospital using hamstrings graft and the 2.0OrthoPilot-B. Braun-Aesculap ACLnavigation system. The average age of patients was 27.8 years. The double-looped semitendinosus tendon replicating the AM bundle was fixed first at 60° of knee flexion. Than the gracilis tendon replicating the PL bundle was fixed at 15° of knee flexion. Maximum manual A–P displacement at 30° of flexion, maximum internal and external rotation of the knee were evaluated using the navigation system before surgery and after single(A–M)and double (AM+PL)bundle reconstruction. Statystical anlisys was done using paired T-test. Before ACL reconstruction mean manual maximum AP displacement was 17.2mm;mean manual maximum internal rotation was 19.8mm and mean manual maximum external rotation was 16.8mm. After AM bundle reconstruction mean manual maximum AP displacement was 6.1mm;mean manual maximum internal rotation was 17.0mm and mean manual maximum external rotation was 16.3mm. After AM+PL bundles reconstruction mean manual maximum AP displacement was 5.3mm;mean manual maximum internal rotation was 16.2mm and mean manual maximum external rotation was 14.6mm. There was no statistically significant difference in the tibial internal rotation at 30° after single bundle(AM)and double bundle(AM+PL)reconstruction. In this study the effectiveness of the PL bundle in controlling the internal rotation of the tibia, responsible of rotational instability of the knee, was evaluated in “in vivo” ACL reconstruction. The navigator system allowed us to obtain “in vivo” the real and correct value of AP displacement and internal and external rotation of the tibia before and after reconstruction. Our hypothesis that the addition of the PL bundle to the AM bundle is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion, minimizing the pivot shift phenomenon, on the basis of our study has not been confirmed.
The purpose of this paper is to investigate the relative contribution of each component in the ultimate strength and stiffness of the Evolgate (Citieffe), which is presently a widely used fixation device in DGST ACL reconstruction. The three components of the Evolgate were tested using fresh frozen animal tissue stored at −20° Celsius. Common extensor tendons were harvested from 20-month-old bovine forelimbs. Twenty-four tests were performed for each of the following configurations: six tests using Evolgate complete, six tests using screw alone, six tests using screw and washer and six tests using screw and coil. A randomised t-test was used; differences were considered significant when p<
0.05. The mean strength was: Evolgate complete 1314±194N; coil and screw 700±152N; screw alone 408±86N; and screw and washer 333±93N. There was a significant difference between fixation strength of Evolgate and the other devices, none between screw alone and screw and washer. The mean slippage of the Evolgate was significantly lower than the other devices. The mean stiffness of the Evolgate (269±14 N/mm) was significantly greater than the other devices. On the basis of the results of the present study, the coil appears to be the most important component of the Evolgate, resulting in a significant increase of the fixation strength of the screw. However, it is important to note that, as the washer alone does not improve the strength of the screw, if a washer is associated with a coil a further significant increase in strength and stiffness of the device is observed.
The purpose of this study is to biomechanically evaluate how four different fixation devices (two femoral and two tibial) associated in three different combinations, using cyclic loading with final pull-out test, affect the strength and the stiffness of the femur-graft-tibia complex. We conducted a controlled laboratory study and tested, using cyclic loading with final pull-out, two femoral devices (Swing- bridge and Endobutton CL) and two tibial device (Evolgate and BioRCI screw) in three different combinations: Group A, EB-Bio RCI; Group B, EB-Evolgate; and Group C, SB- Evolgate. We used porcine knees and bovine digital extensor tendons and evaluated the stiffness and strength at the final pull-out, and the displacement at the 1st, 100th, 300th, 500th and 1000th cycle. A t-test was used for statistical evaluation. There was a statistically significant difference in ultimate failure load between group A and group B (p=0.03) and group A and group C (p=0.0007) but no difference between group B and group C (p=0.72). There was a statistically significant difference in ultimate failure load between group A and group C (p=0.02) and group B and group C (p=0.01) but no difference between group A and group B (p=0.88). Due to the biomechanical properties of the F-G-T complex the combination of Swing-Bridge and Evolgate seems to be a good alternative when an accelerated post-operative rehabilitation is planned after ACL reconstruction using DGST.
The purpose of our study was to determine the effect of 4 weeks and 12 weeks of implantation on the strength of a tendon graft in a bone tunnel using a low-profile fixation device, Evolgate, in an extra-articular ovine model. Moreover, we evaluated the histological changes. The common digital extensor tendon was detached from the lateral femoral condyle and fixed with the Evolgate device in a 30-mm-long tunnel placed obliquely across the dense metaphyseal bone of the proximal tibia. We performed either biomechanical or histological study. Three sheep were sacrified at time 0 and their posterior limbs were used for biomechanical tests. Six sheep were used for biomechanical tests at time 1 (4 weeks) and at time 2 (12 weeks). The other three sheep were used for histological evaluation after 4 and 12 weeks of implantation. The biomechanical tests included a 50 N preload applied for 10 s and a cyclic load test in 50-N increments until failure to evaluate the ultimate failure load. We used a paired t-test to evaluate the difference between group at T1 and group at T2 with the control group at time 0, respectively. Tests were performed using an electromechanic machine (Zwick-Roell Z010, Zwick-Roell, Ulm, Germany). Data were recorded with dedicated software (Textexpert 8.1, Zwick-Roell). The biomechanical results show an improvement of about 50% in strength after 4 and 12 weeks post-implantation, respectively. The histological evaluation shows a layer of cellular, fibrous tissue between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganised during the healing process. The collagen fibres that attached the tendon to the bone resembled Sharpey fibres. The strength of the interface was noted to have significantly and progressively increased between the second and the 12th week after the transplantation. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralisation, and maturation of the healing tissue, noted histologically.
Secure tendon-to-bone fixation is essential for successful rotator cuff repair. Thus, the biomechanical properties of devices used in rotator cuff repair should be better understood. This controlled laboratory study was performed to evaluate response to incremental cyclic loading of six different anchor-wire complexes commonly used in rotator cuff repair. Two absorbable anchors 5 and 6.5 mm in diameter and one metallic anchor, coupled with both ethibond or fibrewire (FW) were tested on five pairs of fresh-frozen human cadaveric shoulders. An incremental cyclic load was applied until failure using a Zwich-Roell Z010 electromechanical testing machine. The ultimate failure load and mode of failure were recorded. A t-test was used for statistical analysis. The FW suture coupled both with absorbable and metallic anchors provides a statistically significant stronger fixation. However, while the metallic anchors in most cases fail due to the slippage of the anchor, absorbable anchors fail due to rupture of the loop. The FW seems to increase the strength of fixation devices under cyclic load both using absorbable or metallic anchors with relevant differences in failure mode (slippage of the metallic anchor and loop failure in absorbable ones). Using a FW suture, the risk of metallic anchor migration might increase.
