Effect of inverse kinematic alignment total knee arthroplasty on coronal alignment of the ankle joint in patients with varus knee deformity.

INTRODUCTION: Varus or valgus knee deformities influence ankle coronal alignments. The impact of Total Knee Arthroplasty (TKA) on ankle joint alignment has not been entirely illustrated. Inverse Kinematic Alignment (iKA) is a surgical philosophy that aims to restore soft tissue balance, function, and native anatomy within validated boundaries to restore restrictive native kinematics. Therefore, this study aimed to investigate the postoperative association of patient-specific alignment on the coronal alignment of the ankle in patients with varus knee deformity who underwent iKA TKA. We hypothesized that greater preoperative varus malalignments would correlate with significant postoperative ankle coronal alignment changes. METHODS: This retrospective study of a prospective collected cohort assessed patients who underwent imageless navigation assisted robotic TKA using a single implant design for primary osteoarthritis between January 2022 and August 2023. Preoperative and postoperative full-length standing anteroposterior X-ray imaging was used to measure Hip-Knee-Ankle (HKA), Tibial Plafond Inclination (TPI), Talar inclination (TI), and Tibiotalar Tilt (TTT) angles. Patients were subsequently divided into groups of neutral varus) < 10°) and severe varus (≥ 10°) according to the preoperative HKA angle. RESULTS: Significant changes in preoperative and postoperative HKA angles were found in the severe varus (14.5° vs. 6.4°, p < 0.001) group. Changes were also significant between preoperative and postoperative TPI and TI angles in the severe varus group; however, TTT did not reach statistical significance. Delta change from pre- to postoperative HKA was significantly higher for the severe varus group (8.1° vs. 0.8°, p < 0.019). Delta change of TPI, TI and TTT did not differ between groups. CONCLUSION: Coronal knee alignment after TKA affects coronal alignment of the ankle. iKA technique in TKA for varus knee deformity preserves or minimizes substantial coronal alignment changes of the ankle joint. These findings may add to the benefits reported for patient specific alignment TKA techniques. LEVEL OF EVIDENCE: III.

Better restoration of joint line obliquity in tibia first restricted kinematic alignment versus mechanical alignment TKA.

INTRODUCTION: In total knee arthroplasty (TKA), suboptimal restoration of joint line obliquity (JLO) and joint line height (JLH) may lead to diminished implant longevity, increased risk of complications, and reduced patient reported outcomes. The primary objective of this study is to determine whether restricted kinematic alignment (rKA) leads to improved restoration of JLO and JLH compared to mechanical alignment (MA) in TKA. MATERIALS AND METHODS: This retrospective study assessed patients who underwent single implant design TKA for primary osteoarthritis, either MA with manual instrumentation or rKA assisted with imageless navigation robotic arm TKA. Pre- and post-operative long standing AP X-ray imaging were used to measure JLO formed between the proximal tibial joint line and the floor. JLH was measured as the distance from the femoral articular surface to the adductor tubercle. RESULTS: Overall, 200 patients (100 patients in each group) were included. Demographics between the two groups including age, sex, ASA, laterality, and BMI did not significantly differ. Distribution of KL osteoarthritis classification was similar between the groups. For the MA group, pre- to post-operative JLO significantly changed (2.94° vs. 2.31°, p = 0.004). No significant changes were found between pre- and post-operative JLH (40.6 mm vs. 40.6 mm, p = 0.89). For the rKA group, no significant changes were found between pre- and post-operative JLO (2.43° vs. 2.30°, p = 0.57). Additionally, no significant changes were found between pre- and post-operative JLH (41.2 mm vs. 42.4 mm, p = 0.17). Pre- to post-operative JLO alteration was five times higher in the MA group compared to the rKA group, although this comparison between groups did not reach statistical significance (p = 0.09). CONCLUSION: rKA-TKA results in high restoration accuracy of JLO and JLH, and demonstrates less pre- and post-operative JLO alteration compared to MA-TKA. With risen interest in joint line restoration accuracy with kinematic alignment, these findings suggest potential advantages compared to MA. Future investigation is needed to correlate between joint line restoration accuracy achieved by rKA and enhanced implant longevity, reduced risk of post-operative complications, and heightened patient satisfaction.

Higher rates of intraoperative fractures with compaction broaching compared to conventional broaching during hip hemiarthroplasty for femoral neck fractures.

PURPOSE: Intraoperative periprosthetic femoral fracture (IPFF) is a known iatrogenic complication during hemiarthroplasty (HA) which may lead to inferior outcomes. The risk factors for IPFF during HA in displaced femoral neck fractures (FNF) remains to be fully elucidated. This study aims to compare IPFF rates between compaction broaching and conventional broaching techniques for cementless HA in FNF. METHODS: We retrospectively reviewed institutional surgical data of patients who underwent cementless HA for displaced FNF from January 2010 to January 2022. Patients were stratified into two groups based on the broaching system: conventional broaching and compaction broaching. The presence, location, and treatment of IPFF were assessed for both groups. Effect of IPFF on postoperative weight-bearing status, mortality readmission and revision rates were compared between groups. RESULTS: A total of 1,586 patients included in the study. 1252 patients (78.9%) in the conventional broaching group and 334 patients (21.1%) in the compaction broaching group. A total of 104 IPFF were found (6.5%). As compared to conventional broaching, compaction broaching was associated with significant higher IPFF rates (12.9% vs. 4.9%, p < 0.001, OR 2.84, CI 1.88-4.30). The location of the IPFF was similar between groups (p = 0.366), as well as the intraoperative treatment (p = 0.103) and postoperative weight-bearing status (p = 0.640). Surgical time, mortality rates, readmission rates and revision rates were comparable between groups. In a multivariate regression analysis, compaction broaching (OR, 4.24; p < 0.001) was independently associated with IPFF. CONCLUSIONS: This study reveals higher rates of IPFF associated with compaction broaching. Although this finding may have minimal clinical relevance, surgeons should consider these results when considering implant selection.

Does addition of gentamicin for antibiotic prophylaxis in total knee arthroplasty reduce the rate of periprosthetic joint infection?

BACKGROUND: First-generation cephalosporins are used as antibiotic prophylaxis in total joint arthroplasty patients. However, this regimen does not address Gram-negative bacteria causing periprosthetic joint infection (PJI). Previous studies have suggested that the addition of an aminoglycoside as antibiotic prophylaxis in THA reduces surgical site infection (SSI), and less is known on its effect in TKA. This study aimed to investigate if the addition of a single-dose gentamicin, administered pre-operatively, is associated with lower rates of infection in TKA patients. PATIENTS AND METHODS: This is a retrospective study of patients who underwent primary TKA as treatment for osteoarthritis between January 2011 and April 2021, with a minimum 1-year follow-up. The mean age was 69.9 (± 9.8), the mean BMI was 29.7 (± 5.5), and most patients had American Society of Anaesthesiology (ASA) score of 2-3 (92.9%). Patients were stratified based on the peri-operative antibiotic prophylaxis they received: cefazolin with addition of gentamicin (case group) or cefazolin (control group). Our primary study endpoints were rates of PJI and SSI, which were compared between groups using the chi-square test. Statistical significance was set as p < 0.05. RESULTS: The final study population consisted of 1590 patients, 1008 (63.4%) in the control group and 582 (36.6%) patients in the case group. The total infection rate for patients that received gentamicin dropped by 34%; however, this finding did not reach statistical significance (1.3% (control) vs. 0.86% (case), p = 0.43). The same drop was seen after subdivision of infections to PJI (0.5% vs. 0.34%, 32% drop, p = 0.66) and SSI (0.8% vs. 0.52%, 35% drop, p = 0.52). CONCLUSIONS: A single dose of gentamicin administered pre-operatively to a standard antibiotic prophylaxis was not associated with a statistically significant lower rate of PJI. Although the difference in infection rate did not reach statistical significance, the current study noted a drop in the rate of infection by 1/3 in the gentamicin cohort. Further investigation to evaluate the potential benefit of adding gentamicin to a peri-operative antibiotic regimen is warranted.

Good clinical and radiological outcomes of the varus-valgus constrained mobile-bearing implant in revision total knee arthroplasty.

PURPOSE: Knee instability is one of the most common indications for having to undergo revision total knee arthroplasty (RTKA) and can be prevented with adequate implant selection and good surgical technique. Varus-valgus constrained implants (VVC) are indicated for cases of RTKA with absent ligament function in order to provide the necessary stability. While mobile-bearing articulations are thought to decrease the risk of aseptic loosening in comparison to their fixed-bearing counterparts, there is limited data on their outcomes. The purpose of our study is to present the clinical and radiological outcomes for patients undergoing an RTKA procedure with the mobile-bearing VVC implant. METHODS: Between January 2008 to January 2018, 93 patients underwent RTKA with the use of varus-valgus mobile-bearing (VVCMB) prosthesis. The main indications for RTKA were instability 38.7% (n = 36), aseptic loosening 31.2% (n = 29), infection in 26.9% (n = 25), and other 3.3%. The mean follow-up time was 56 months. Clinical outcomes were assessed by knee society scores, range of motion, and rate of re-operation. RESULTS: The mean knee society score increased significantly from 65.52 pre-operatively to 89.65 post-operatively (p < 0.001). The five year cumulative incidence of re-operation in our study was 7.53% (n = 7). Our study reported no cases of aseptic loosening or mobile-bearing spin-out. The number of flexion contractures decreased from n = 23 (24.7%) pre-operatively to n = 11 (11.8%) post-operatively (p < 0.05). CONCLUSION: The VVC mobile-bearing prosthesis demonstrated good clinical outcomes and mid-term survivorship in patients undergoing RTKA. Additional follow-up is required in the long term.

Effects of surgeon experience and patient characteristics on accuracy of digital pre-operative planning in total hip arthroplasty.

BACKGROUND: The effect of surgeon experience on accuracy of digital pre-operative planning for total hip arthroplasty (THA) remains unclear. The aims of our study were to compare pre-operative planning accuracy between fellow-trained orthopaedic surgeons and residents and to explore whether surgery indication effects the prediction accuracy. METHODS: We prospectively reviewed 101 patients who underwent pre-operative digital templating for THA in our center from January 2019 to January 2020 with King Mark device. Extracted data included baseline characteristics and indication for primary arthroplasty. Pre-operative digital templating was performed separately by both a fellow-trained surgeon and a resident. Accuracy of each group was compared with the implanted components. RESULTS: The overall adequate pre-operative planning of the acetabular cup (exact or +/-1 size match) by the fellow-trained group was higher compared with the resident's group (77.2 and 64.3% respectively, p = 0.037), whereas the overall adequate pre-operative planning of the femoral stem (exact or +/-1 size match) was higher in the resident's group compared with the fellow-trained group (83.2 and 61.4% respectively, p < =0.001). The fellow-trained group showed better pre-operative planning of complex cases (developmental dysplasia of the hip and avascular necrosis of femoral head) than the resident's group. CONCLUSIONS: The experience of the planner does not significantly affect the accuracy of correctly predicting component sizes. However, in complex cases, fellow-trained surgeons should assist residents in digital pre-operative templating for THA.

Is continuation of anti-platelet treatment safe for elective total hip arthroplasty patients?

INTRODUCTION: Acetylsalicylic acid (aspirin) is a commonly prescribed medication, especially in the age group of individuals who undergo elective total hip arthroplasty (THA). Preoperative discontinuation of aspirin is believed to reduce intraoperative bleeding and other complications, but it may increase the risk of perioperative cardiovascular events. In this study we have sought to evaluate the safety of continuous aspirin treatment in patients undergoing elective THA. MATERIALS AND METHODS: This is a retrospective analysis of a consecutive cohort who underwent elective THA in a tertiary medical center between 2011 and 2018. The cohort was divided into two groups-one that received continuous preoperative aspirin treatment and one that did not. Blood loss, peri- and postoperative complications, readmissions, and short- and long-term mortality were compared between groups. RESULTS: Out of 757 consecutive patients (293 males, 464 females) who underwent elective primary THA, 552 were in the "non-aspirin" group and 205 were in the "aspirin" group and were not treated preoperative with other medication affecting hemostasis. Perioperative continuation of aspirin treatment did not significantly increase perioperative bleeding, as indicated by changes in hemoglobin levels (P = 0.72). There were no significant differences in short- and long-term mortality (P = 0.47 and P = 0.4, respectively) or other perioperative complications, such as readmission (P = 0.78), deep or superficial infection (P = 1 and P = 0.47, respectively), and cardiovascular events (none in both groups). CONCLUSION: Peri-operative continuation of aspirin treatment in patients undergoing elective primary THA did not increase perioperative complications or mortality compared to the non-aspirin-treated patients. The protective effects of aspirin from postoperative thrombotic and cardiovascular events are well documented. The current findings dispute the need to preoperatively withhold aspirin treatment in patients undergoing elective primary THA.

Inhibition of nucleotide pyrophosphatase/phosphodiesterase 1: implications for developing a calcium pyrophosphate deposition disease modifying drug.

Objectives: Calcium pyrophosphate deposition (CPPD) is associated with osteoarthritis and is the cause of a common inflammatory articular disease. Ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (eNPP1) is the major ecto-pyrophosphatase in chondrocytes and cartilage-derived matrix vesicles (MVs). Thus, eNPP1 is a principle contributor to extracellular pyrophosphate levels and a potential target for interventions aimed at preventing CPPD. Recently, we synthesized and described a novel eNPP1-specific inhibitor, SK4A, and we set out to evaluate whether this inhibitor attenuates nucleotide pyrophosphatase activity in human OA cartilage. Methods: Cartilage tissue, chondrocytes and cartilage-derived MVs were obtained from donors with OA undergoing arthroplasty. The effect of SK4A on cell viability was assayed by the XTT method. eNPP1 expression was evaluated by western blot. Nucleotide pyrophosphatase activity was measured by a colorimetric assay and by HPLC analysis of adenosine triphosphate (ATP) levels. ATP-induced calcium deposition in cultured chondrocytes was visualized and quantified with Alizarin red S staining. Results: OA chondrocytes expressed eNPP1 in early passages, but this expression was subsequently lost upon further passaging. Similarly, significant nucleotide pyrophosphatase activity was only detected in early-passage chondrocytes. The eNPP1 inhibitor, SK4A, was not toxic to chondrocytes and stable in culture medium and human plasma. SK4A effectively inhibited nucleotide pyrophosphatase activity in whole cartilage tissue, in chondrocytes and in cartilage-derived MVs and reduced ATP-induced CPPD. Conclusion: Nucleotide analogues such as SK4A may be developed as potent and specific inhibitors of eNPP1 for the purpose of lowering extracellular pyrophosphate levels in human cartilage with the aim of preventing and treating CPPD disease.

Galectin-3 is a sensor-regulator of toll-like receptor pathways in synovial fibroblasts.

Galectin-3 is a ß-galactoside-binding lectin that plays an important role in the modulation of immune responses. It has been shown to aggravate joint inflammation and destruction in experimental arthritis. We investigated the role of galectin-3 in TLR-induced cell activation in human synovial fibroblasts (SF) in order to better understand the mechanism(s) of the proinflammatory function of galectin-3 in arthritis. Galectin-3 expression in SF obtained from rheumatoid arthritis and osteoarthritis patients was inhibited by siRNA mediated gene-knockdown. Galectin-3 was also inhibited with modified citrus pectin (MCP), a polysaccharide galectin-3 ligand. Galectin-3 knockdown inhibited TLR-2, -3 and -4-induced IL-6 secretion, but not TLR-2, -3 and -4-mediated matrix metalloproteinase-3 or CC chemokine ligand-5 secretion. When the SF were stimulated with phorbol 12-myristate 13-acetate, a protein kinase C activator that bypasses the membranal receptors, galectin-3 knockdown no longer influenced IL-6 secretion. MCP reduced IL-6 levels in a dose-dependent manner. Our results indicate that galectin-3 is a positive sensor-regulator of TLR-induced IL-6 secretion in human synovial fibroblasts, thus adding new insights into the mechanisms by which galectin-3 augments synovial inflammation. These findings corroborate the potential role of glycan inhibitors of galectin-3 as a therapeutic approach for the treatment of inflammatory arthritis.

Long-Term Outcomes Following Reduction and Fixation of Displaced Subcapital Hip Fractures in the Young Elderly.

BACKGROUND: The surgical treatment of hip fractures remains controversial especially when considering age. OBJECTIVES: To investigate the long-term functional outcomes of displaced subcapital hip fractures that were reduced and surgically fixed using parallel cannulated screws in patients aged 60 years and younger. METHODS: During the period 1996-2005, 27 patients under age 60 with displaced subcapital hip fractures classified as Garden III or IV were treated with fracture reduction and surgical internal fixation using cannulated screws. Patient outcomes were assessed using the Harris Hip Score (HHS) and physical examination. RESULTS: During a follow-up period of 8-17 years 4 of the 27 patients (14.8%) developed non-union/femoral head avascular necrosis and had undergone hip arthroplasty. All reoperations were performed within the first year after fracture fixation, all in the 50-60 year old age group. The revision rate among patients 50-60 years old was significantly higher than that of patients 50 years and younger (40% vs. 0%, P = 0.037). Mean HHS was higher for patients not requiring revision surgery (85.4) than for patients with revision surgery (75.5), but this difference was not significant. CONCLUSIONS: Internal fixation using fracture reduction and cannulated screw fixation is a successful treatment modality for displaced subcapital hip fractures in patients under 50 years old. Patients aged 50-60 may have a higher risk of avascular necrosis or non-union and require arthroplasty, often within the first year after fracture fixation. The long-term outcome following these fractures is good when excluding patients who had early complications.

Age as a Risk Factor for Intraoperative Periprosthetic Femoral Fractures in Cementless Hip Hemiarthroplasty for Femoral Neck Fractures: A Retrospective Analysis.

Background: Understanding the risk factors and outcomes of intraoperative periprosthetic femoral fractures (IPFF) during hip arthroplasty is crucial for appropriate perioperative management. Previous studies have identified risk factors for IPFF in total hip arthroplasty patients, but data for hip hemiarthroplasty (HA) is lacking. The aim of this study was to determine the age associated with increased rates of IPFF in patients undergoing HA. Methods: We retrospectively reviewed patients aged 65 years and above who underwent a cementless HA for a displaced femoral neck fracture and had a minimum of 1-year follow-up. Patients were stratified into five age groups (65-79, 80-84, 85-89, 90-94, and ≥ 95 years) and further divided into two subgroups (under 95 years and 95 years or older). The presence, location, and treatment of IPFF, as well as the effect of IPFF on the postoperative weight-bearing status, were compared between groups. A multivariate logistic regression was also performed. A total of 1,669 met the inclusion criteria and were included in the study. Results: The rates of IPFF were significantly higher for patients 95 years or older (p = 0.030). However, fracture location (greater trochanter fractures, p = 0.839; calcar fractures, p = 0.394; and femoral shaft fractures p = 0.110), intraoperative treatment (p = 0.424), and postoperative weight-bearing status (p = 0.229) were similar between the groups. While mortality and nonorthopedic-related readmissions were significantly higher for patients 95 years or older, orthopedic-related readmissions (p = 0.148) and revisions at the latest follow-up (p = 0.253) were comparable between groups. In a regression analysis, age over 95 years (odds ratio, 2.049; p = 0.049) and body mass index (odds ratio, 0.935; p = 0.016) were independently associated with IPFF. Conclusions: The findings of this study suggest that age over 95 years is a significant, independent risk factor for IPFF in patients undergoing cementless HA. Although we were unable to show an impact on perioperative outcomes and orthopedic complications, when operating on patients 95 years or older, surgeons should be aware of the increased risk of IPFF and consider the use of stem designs and fixation types associated with decreased IPFF rates.

Radiological Comparison of Canal Fill between Collared and Non-Collared Femoral Stems: A Two-Year Follow-Up after Total Hip Arthroplasty.

Collared femoral stems in total hip arthroplasty (THA) offer reduced subsidence and periprosthetic fractures but raise concerns about fit accuracy and stem sizing. This study compares collared and non-collared stems to assess the stem-canal fill ratio (CFR) and fixation indicators, aiming to guide implant selection and enhance THA outcomes. This retrospective single-center study examined primary THA patients who received Corail cementless stems between August 2015 and October 2020, with a minimum of two years of radiological follow-up. The study compared preoperative bone quality assessments, including the Dorr classification, the canal flare index (CFI), the morphological cortical index (MCI), and the canal bone ratio (CBR), as well as postoperative radiographic evaluations, such as the CFR and component fixation, between patients who received a collared or a non-collared femoral stem. The study analyzed 202 THAs, with 103 in the collared cohort and 99 in the non-collared cohort. Patients' demographics showed differences in age (p = 0.02) and ASA classification (p = 0.01) but similar preoperative bone quality between groups, as suggested by the Dorr classification (p = 0.15), CFI (p = 0.12), MCI (p = 0.26), and CBR (p = 0.50). At the two-year follow-up, femoral stem CFRs (p = 0.59 and p = 0.27) were comparable between collared and non-collared cohorts. Subsidence rates were almost doubled for non-collared patients (19.2 vs. 11.7%, p = 0.17), however, not to a level of clinical significance. The findings of this study show that both collared and non-collared Corail stems produce comparable outcomes in terms of the CFR and radiographic indicators for stem fixation. These findings reduce concerns about stem under-sizing and micro-motion in collared stems. While this study provides insights into the collar design debate in THA, further research remains necessary.

Clinical and radiographic outcomes of 139 hips with articular surface replacement total hip arthroplasty*.

BACKGROUND: The articular surface replacement (ASR) total hip arthroplasty (THA) was recently recalled from the market due to high failure rates. This modality was used frequently by surgeons at our medical center. OBJECTIVES: To assess the clinical and radiographic outcomes in patients following the surgery and determine the revision rate in our cohort. METHODS: Between 2007 and 2010 139 hips were operated on and evaluated in our clinic. All patients underwent a clinical interview, function and pain evaluation, as well as physical examination and radiographic evaluation. When necessary, patients were sent for further tests, such as measuring cobalt-chromium levels and magnetic resonance hip imaging. RESULTS: With an average follow-up of 42 months the revision rate was 2% (3/139). Patients reported alleviation of pain (from 8.8 to 1.7 on the Visual Analog Scale, P < 0.001), good functional outcomes on the Harris Hip Score, and improved quality of life. Overall satisfaction was 7.86 on the reversed VAS. For patients who required further tests, clinical and radiographic outcomes were significantly poorer than for the rest of the cohort. Average blood ion levels were high above the normal (cobalt 31.39 ppb, chromium 13.32 ppb), and the rate of inflammatory collection compatible with pseudotumors on MRI was 57%. DISCUSSION: While our study favors the use of the ASR implant both clinically and radiographically, some patients with abnormal ion levels and inflammatory collections on MRI might require revision in the future.

An international survey on anterior cruciate ligament reconstruction practices.

PURPOSE: Bone-patellar-tendon-bone (BPTB) autografting fixed with metal interference screws (IS) is the gold standard for anterior cruciate ligament (ACL) reconstruction. Advances in surgical technology provide a wide choice of grafts, fixation devices and surgical approaches. METHODS: Two-hundred and sixty-one orthopedic surgeons of ten subspecialties from 57 countries were surveyed on their choice of graft and fixation device, the number of reconstructed bundles, and arthroscopic portal. Their preferences were analyzed according to country of origin, field of expertise and seniority, and compared to current publications. RESULTS: Hamstring autografting was the most popular choice (63 %), then BPTB (26 %) and allograft (11 %). The anteromedial portal was preferred over the traditional transtibial portal (68 % versus 31 %). Two-thirds reported routinely performing a single-bundle graft reconstruction, compared to one-third who used the double-bundle technique. The Endo-button was the most common graft fixation method (40 %), followed by the bioabsorbable IS (34 %), metallic IS (12 %), rigidfix (10 %) and others (4 %). The preferences of hamstring tendon grafting and the anteromedial portal are not supported in the literature. Responses from North American and European surgeons were different from all the others. CONCLUSIONS: Surgeon preferences in ACL reconstruction differ considerably worldwide. Common practice is not always supported by evidence-based publications.

Outcomes of Enterobacter cloacae-Associated Periprosthetic Joint Infection Following Hip Arthroplasties.

Background: Periprosthetic joint infections (PJIs) represent a serious complication following total hip arthroplasty (THA) and are associated with significant morbidity. While recent data suggest that Enterobacter cloacae is an emerging source of PJI, characteristics and outcomes of E. cloacae-associated infections are rarely described. The study aimed to present and describe the findings and outcomes of E. cloacae-associated PJI in our department. Methods: This is a retrospective descriptive study of patients who underwent revision THA for E. cloacae-associated PJI between 2011 and 2020 and has a minimum follow-up of 2 years. Outcomes included organism characteristics as well as clinical outcomes, represented by the number of reoperations needed for PJI eradication and the Musculoskeletal Infection Society (MSIS) outcome reporting tool score. Of 108 revision THAs, 12 patients (11.1%) were diagnosed with E. cloacae-associated PJI. Results: The majority of cases had a polymicrobial PJI (n=8, 66.7%). Five E. cloacae strains (41.7%) were gentamicin-resistant. Six patients (50.0%) underwent 2 or more revisions, while 3 of them (25.0%) required 4 or more revisions until their PJI was resolved. When utilizing the MSIS outcome score, the first surgical intervention was considered successful (MSIS score tiers 1 and 2) for 5 patients (41.7%) and failed (tiers 3 and 4) for 7 patients (58.3%). Conclusions: E. cloacae is emerging as a common source of PJI following hip arthroplasty procedures. The findings of our study suggest that this pathogen is primarily of polymicrobial nature and represents high virulence and poor postoperative outcomes, as represented by both an increased number of required revision procedures and high rates of patients with MSIS outcome scores of 3 and 4. When managing patients with E. cloacae-associated PJI, surgeons should consider these characteristics and inform patients regarding predicted outcomes.

The effect of patient body mass index and sex on the magnification factor during pre-operative templating for total hip arthroplasty.

INTRODUCTION: Pre-operative templating prior to hip arthroplasty has traditionally used implant-company-provided acetates, which assumed a magnification factor between 115% and 120%. In recent years, pre-operative planning has been performed with digital calibration devices, in order to calculate the magnification factor. However, these devices are not without their limitations and are not readily available at many institutions. As previous reports suggest a wide range of magnification factors, the determination of an optimal magnification factor is currently unclear. We investigated the relationship between obesity and gender on the magnification factor in order to improve the accuracy of pre-operative templating. PATIENTS AND METHODS: Ninety-seven consecutive pre-operative calibrated pelvic radiographs using the KingMark calibration were analyzed using the TraumaCad templating software. The magnification factor calculated by the software was considered the true magnification factor and analysis was made in order to assess the effect of sex and body mass index (BMI) on the magnification factor. A linear regression analysis was utilized to create a predictive model for optimal magnification factor value. RESULTS: Magnification factor was significantly affected by sex (male, 120.0% vs. female 121.2%, p < 0.01) and by categorized BMI (obese 121.8% vs. non-obese 119.9%, p < 0.001). A positive linear association was found between BMI and the magnification factor (r = 0.544). The magnification factor was significantly different between the following sub-groups: obese female, non-obese female, obese male, and non-obese male (p < 0.001). When applying the model formulated by the linear regression analysis, the calculated magnification factor was within 2% of the true magnification factor for the majority of patients (n = 83, 85.6%). CONCLUSIONS: BMI and gender have a significant effect on the magnification factor. Future determination of the magnification factor should consider the influence of these variables in order to improve the accuracy of pre-operative templating in THA.

Long term results of total hip arthroplasty with cemented and cementless tapered femoral component.

BACKGROUND: Excellent midterm results for total hip arthroplasties (THA) with cementless, tapered porous Taperloc® femoral stems have been reported. Reports regarding such cemented stems, however, are lacking. OBJECTIVES: To evaluate the long-term outcomes of both cemented and cementless THAs with the Taperloc femoral component. METHODS: The medical records of 71 patients (76 hips), operated on between January 1991 and December 2003, who had a minimum follow-up of 10 years were available for analysis. Functional analysis was performed with the Harris hip score (HHS) questionnaire and the numerical analogue scale (NAS). Radiographic analysis was performed for subsidence, radiolucent lines and osteolysis. RESULTS: The cohort was comprised of 47 female and 24 male patients, with a mean age of 59.7 ± 12.4 years. The mean follow-up was 17.8 ± 4.4 years. 52.6% of THAs analyzed were cementless and 47.4% were cemented. Post-operative radiographs were available for 57 surgeries. Subsidence, hypertrophic ossification, radiolucent lines and osteolysis were noted in 4 (7%), 2 (2.6%), 14 (18.4%) and 11 (14.5%) hips respectively. The average HHS score at a mean follow-up of 20.1 ± 3.9 years was 62.1 (±27.7) and the NAS score was 4.6 (±3.6). During the study period, five revision surgeries were performed due to stem-related problems, one of which was for aseptic loosening. CONCLUSIONS: Our long-term experience with the Taperloc stem, both cemented and cementless, demonstrates good outcomes, with low rates of failure. This makes this prosthesis an attractive option for THAs. LEVEL OF EVIDENCE: IV.

Addition of gentamicin for antibiotic prophylaxis in hip hemiarthroplasty does not decrease the rate of surgical site infection.

BACKGROUND: The addition of Gram-negative coverage to antibiotic prophylaxis protocols prior to elective total hip arthroplasty (THA) has been reported to reduce periprosthetic joint infection (PJI). However, it is unknown whether adding a Gram-negative-targeted antibiotic agent improves outcomes in the trauma population. This study aimed to investigate whether the addition of a single, pre-operative dose of Gentamicin is associated with lower rates of PJI in patients undergoing hemiarthroplasty (HA) as treatment for a hip fracture. METHODS: We retrospectively reviewed cases of patients who underwent HA as treatment for a hip fracture from January 2011 to January 2022, and had a minimum 1-year of follow-up. Patients were divided into two groups based on the antibiotic prophylaxis they received during surgery: cefazolin (control group) or cefazolin with addition of Gentamicin (case group). The primary outcome was the rate of surgical site infections (SSI), and secondary outcomes included rates of prosthetic joint infection (PJI) and superficial SSIs. RESULTS: The final study population consisted of 1521 patients. 336 patients (22.1%) were in the case group and 1185 (77.9%) patients were in the control group. Rates of SSI were comparable between the groups (3.8% for the case group vs. 2.8% in the control group, p = 0.34). This held true for both PJIs (3.5 vs. 2.5%, p = 0.3) and superficial SSIs (0.29 vs. 0.33%, p = 0.91). The distribution of the causing pathogen was similar between the groups (p = 0.84). Gentamicin susceptibility rates of the Gram-negative bacteria associated with PJI were similar between the cohorts (p = 0.51). CONCLUSIONS: The addition of a single, pre-operative dose of Gentamicin to the antibiotic prophylaxis protocol of patients undergoing HA as treatment for a hip fracture was not associated with lower rates of SSI, PJI or superficial SSI. The findings of this study indicate that the prophylactic benefits of Gentamicin may not apply to HA as they do to THA.

Screening for hereditary haemochromatosis in patients undergoing knee arthroplasty : a retrospective cohort study of 2,035 patients.

AIMS: Hereditary haemochromatosis is a genetic disorder that is caused by several known mutations in the human homeostatic iron regulator protein (HFE) gene. Abnormal accumulation of iron causes a joint disease that resembles osteoarthritis (OA), but appears at a relatively younger age and is accompanied by cirrhosis, diabetes, and injury to other organs. Increased serum transferrin saturation and ferritin levels are known markers of haemochromatosis with high positive predictive values. METHODS: We have retrospectively analyzed the iron studies of a cohort of 2,035 patients undergoing knee joint arthroplasty due to OA. RESULTS: No patients had HFE gene C282Y, S65C, or H63D mutations testing. In total, 18 patients (2.96%) of the male cohort and 51 (3.58%) of the female cohort had pathologically increased ferritin levels that may be indicative of haemochromatosis. Seven patients (0.34%) had serum transferrin saturation above 45%. CONCLUSION: The awareness for the diagnosis of this disorder in Orthopaedics is low and needs improvement. Osteoarthritic patients undergoing knee arthroplasty should be routinely screened for haemochromatosis by iron studies and referred to genetic testing when needed. Level of evidence: Level III - Retrospective cohort study. Cite this article: Bone Jt Open 2021;2(12):1062-1066.

Mid-term clinical and radiographic outcomes of porous-coated metaphyseal sleeves used in revision total knee arthroplasty.

BACKGROUND: The management of bone defects remains one of the major challenges surgeons are faced with in revision total knee arthroplasty (RTKA). Large and uncontained bone defects are traditionally managed with metaphyseal sleeves that facilitate osseointegration and have reported construct stability. While many studies have presented excellent short-term outcomes using metaphyseal sleeves, less is known on their performance in the longer term. The purpose of this study was to present our mid-term results of the metaphyseal sleeves used in patients undergoing RTKA. MATERIALS AND METHODS: Between January 2007 and January 2015, 30 patients underwent RTKA with the use of a CCKMB prosthesis combined with an osteointegrative sleeve. The main indications for RTKA were instability in 40% of the cases (n = 12), aseptic loosening in 30% (n = 9), infection in 26.7% (n = 8), and "other" in 3.3% (n = 1). The minimal follow-up time was 5 years and the mean follow-up time was 82.4 months (SD = 22.6). Clinical outcomes were assessed by Knee Society scores (KSS), range of motion and rate of re-operation. RESULTS: The mean Knee Society score increased significantly from 72.1 preoperatively to 90.0 postoperatively (p < 0.001). The cumulative incidence of re-operation in our study was 13.3% (n = 4). Our study reported no cases of aseptic loosening or mobile-bearing spin-out. Knee flexion to 90° and more was impossible in seven cases (23.3%) preoperatively and in one case (3.3%) postoperatively. CONCLUSION: Porous-coated metaphyseal sleeves demonstrated excellent rates of survivorship and radiographic ingrowth in the mid-term setting. However, further studies are required to assess their outcomes in the long-term.