Evaluation of conventional and CT-based radiostereometric analysis for inducible displacement measurements after total hip arthroplasty.

Though radiostereometric analysis (RSA) is the gold standard for migration tracking, computed tomography-based RSA (CT-RSA) does not require marker beads and is available for clinical adoption. This study investigated CT-RSA in comparison to RSA for assessing hip implant stability with inducible displacement (ID) examinations. Patients (n = 48) from a previous study returned to be re-examined for femoral stem stability with CT-RSA and RSA imaging. Implant migration since patients last follow-up was calculated as a measure of stability. ID was assessed between alternated leg rotation scans for CT-RSA and between supine and weight-bearing scans for RSA. Measurements from ID and double examinations were compared between CT-RSA and RSA. All stems were well-fixed with migration <0.2 mm/year. ID measurements were lower with CT-RSA than RSA for distal translation (mean difference = 0.122 mm, p < 0.0001), total translation (mean difference = 0.158 mm, p < 0.0001), and total rotation (mean difference = 0.449°, p < 0.0001). The ID and double exam were significantly different for total translation and total rotation for CT-RSA, and significantly different for medial, distal, and total translation, and total rotation for RSA. Precision ranged from 0.049 to 0.130 mm in translation and 0.061° to 0.220° in rotation for CT-RSA, and from 0.108 to 0.269 mm in translation and 0.151° to 0.670° in rotation for RSA. ID measurements from both CT-RSA and RSA were minimal, consistent for a cohort with well-fixed stems. CT-RSA demonstrated superior precision in all axes compared to RSA. Clinical Significance: Future work should explore the use of CT-RSA in patients with suspected loosening as a potential diagnostic tool.

A novel radiological index uses the inner canal diameter and the Citak classification index to predict risk factor for aseptic loosening following hinged total knee arthroplasty.

INTRODUCTION: It remains unclear if distal femoral morphology should be a key consideration when selecting the implant or fixation strategy. A novel radiological index has been proposed to classify patients' distal femoral morphology. This study aims to evaluate the validity of this classification system in a cohort of patients undergoing hinged Total Knee Arthroplasty (TKA), and to determine if distal femoral morphology is a risk factor for aseptic loosening or all cause revision following hinged TKA. MATERIALS AND METHODS: This study was a retrospective analysis of our institutional database. Fifty-nine patients having undergone hinged TKA with adequate radiographs for examination were eligible for inclusion. Radiographic measurements were performed using the Citak radiological index criteria. The proportion of aseptic loosening and all-cause revisions were compared between the different classification groups. RESULTS: The analysis included 41 females (69.5%) and 18 males (30.5%). The mean age of the participants was 71.2 years (SD = 12.6). For inner canal diameter patients were classified as: Type A (31/59, 53%), Type B (19/59, 32%), and Type C (9/59, 15%). For the Index Classification Group, patients were classified as: Group A (26/59, 44%), Group B (20/59, 34%), and Group C (13/59, 22%). There was no significant difference in overall revision rate between the three groups (χ2 = 3.25, P = .197 from a Chi-square test). There was a significantly higher rate of aseptic loosening in Group C compared to Groups A and B, with no significant difference between Groups A and B in terms of aseptic loosening rates (χ2 = 8.72, P = .013 from a Chi-square test). CONCLUSIONS: Distal femoral morphology plays an important role in the risk of aseptic loosening following hinged knee replacement, and should be considered when deciding implant type and fixation in these patients.

The RM Press fit cup™: an investigation in 182 hips at ten-year follow-up.

INTRODUCTION: For over 10 years, the RM Pressfit cup™ has been used in our department. This is a one-piece, elastic, cementless implant designed with standard polyethylene (PE), covered with a thin coating of titanium particles. To date, there is no French study evaluating this cup after more than 10 years. Therefore, we conducted a retrospective study in order to: (1) evaluate the survival of the implant with a minimum follow-up of 10 years, (2) evaluate the functional scores at the last follow-up, (3) measure the wear of the PE, (4) identify radiological loosening, (5) search for risk factors for cup removal, (6) identify complications that required management in the operating theatre. HYPOTHESIS: The working hypothesis was that the survival of this implant was greater than 95% at 10 years' follow-up, in accordance with the criteria of the National Institute for Health and Care Excellence (NICE). MATERIALS AND METHODS: This was a retrospective monocentric study, including adult patients who underwent total hip arthroplasty (THA) with an RM Pressfit cup™ (28 mm friction size) for coxarthrosis (primary or secondary) or femoral head osteonecrosis. Exclusion criteria were a follow-up period of less than 10 years, the placement of an RM Pressfit cup™ as a secondary intention for a THA (n = 5) or following a trochanteric fracture (n = 1). In total, 163 patients (182 hips) with a median age (Q1-Q3) of 63 (56-68) years, and a sex ratio (M/F) of 1.7 were included. Functional scores were evaluated using the Harris and Oxford scores. Radiographs were analyzed in the immediate postoperative period and at the last follow-up. RESULTS: The median follow-up was 10.5 (10-11.5) years. Of the 182 included hips, 7 cups were removed, corresponding to a 10-year survival rate of 96.1% (95% CI [93.3; 96.9]). The median Harris and Oxford scores at 10.5 years were 95 (90-98) and 19 (17-23) points, respectively. The median PE wear rate was 0.058 (0.039-0.087) mm/year. Univariate analysis showed that male gender was associated with PE wear (OR = 3.6; 95% CI [1.3; 12.9] [p = 0.012]). Ten cups (6%) showed radiological instability with migration greater than 3 mm and/or variation in inclination greater than 8 °, and only 9 hips (6%) showed bone resorption. No preoperative or perioperative factors analyzed were associated with cup removal. Dislocation accounted for 71% (n = 5) of the causes of cup removal. Additionally, 6 hips experienced at least one dislocation episode requiring reduction by external maneuvers in the operating room, bringing the overall dislocation rate in the series to 6% (n = 11). Increased cup inclination was the only risk factor for prosthetic dislocation (OR = 1.2; 95% CI [1.09; 1.4] [p = 0.0003]). Overall complications requiring surgical intervention included 15 (8.3%) implanted cups (7 removed cups, 6 dislocation episodes requiring reduction by external maneuvers in the operating room, and 2 hips reoperated for washing and changing of mobile components due to early infection). CONCLUSION: The RM Pressfit cup™ gives good long-term clinical and radiological results with an overall survival of 96.1% and a low complication rate over 10 years. Over the last 2 years the RM Vitamys™ cup has been introduced allowing the use of 32 mm femoral head diameter for size 48 cups, to reduce the risk of dislocation. LEVEL OF EVIDENCE: IV; retrospective cohort.

The role of MRI in the diagnosis of aseptic loosening following total hip arthroplasty.

INTRODUCTION: The role of advanced imaging in diagnosing aseptic implant loosening following total hip arthroplasty (THA) remains unclear. This study aimed to assess the diagnostic value of magnetic resonance imaging (MRI) in detecting aseptic loosening. METHODS: This was a retrospective review of 342 consecutive patients who underwent revision THA between July 2011 and April 2023 and had a pelvis MRI as part of the preoperative diagnostic evaluation. Among them, 62 patients had an intraoperative diagnosis of aseptic loosening of either the femoral or acetabular component. Patients were stratified based on the concordance between their MRI and radiographs findings. RESULTS: Preoperative MRI showed signs of aseptic loosening in 25/62 patients (sensitivity = 40.3%). Similarly, preoperative radiographs demonstrated signs of aseptic loosening in 27 patients (43.5%). Twelve patients (19.4%) had both MRI and radiographs predictive of aseptic loosening, 22 patients (35.5%) did not show signs of aseptic loosening in either MRI or radiographs, and for 28 patients (45.2%), the results were discordant. Among the patients with a negative radiograph for aseptic loosening (n = 35), 13 patients (37.1%) showed signs of aseptic loosening on MRI. CONCLUSION: Aseptic loosening remains an elusive diagnosis, and the findings of this study suggest that the utility of MRI and radiographs as part of the diagnostic process is limited. However, in cases of presumed aseptic loosening with inconclusive radiographs findings, MRI may play a role in improving the diagnostic process. LEVEL OF EVIDENCE: III.

Early Aseptic Tibial Loosening Is a Concern with a Modern Two-Peg Cementless Total Knee Arthroplasty Design.

INTRODUCTION: While early generations of cementless total knee arthroplasty (TKA) had inferior outcomes compared to cemented TKA, modern cementless designs have offered excellent clinical results. The purpose of this study was to compare patient-reported outcome measures (PROMs) and early aseptic revision rates of a specific cementless TKA design featuring a two-pegged tibia to that of its cemented counterpart. METHODS: A retrospective case series of all cementless and cemented TKAs utilizing a single design performed at a single, high-volume academic center was performed. Institutional review board (IRB) approval was obtained. All cases were performed between November 2018 and March 2022. A minimum one-year follow-up was required. Demographics, complications, and reoperation/revision data were collected. Oxford Knee Score (OKS) and Forgotten Joint Score (FJS) were collected at one-year follow-up. Radiographic review was performed for cementless TKAs that were revised or had PROMs < 1 standard deviation (SD) ("poor performers") or had PROMs > 1 SD ("high performers") below or above the mean, respectively. RESULTS: There were 329 cementless and 349 cemented TKAs included. Mean follow-up was 1.9 years and 2.6 years for cementless and cemented cohorts, respectively. There were no statistical PROM differences between the two cohorts. There was no statistical difference in aseptic revision rates between the cohorts (4.0% cementless versus 1.7% cemented, P = 0.078); however, there was a higher rate of tibial aseptic loosening in the cementless cohort (2.7% cementless versus 0% cemented, P = 0.002). The mean time to revision for aseptic tibial loosening was 17.6 months. There was no statistical difference in radiolucencies between "poor performers" and "high performers." CONCLUSION: When compared to its cemented counterpart, the cementless TKA that was reintroduced in 2018 had similar one-year PROMs, but a higher rate of early tibial loosening (2.7 versus 0.0%, P = 0.002).

Prevalence and Risk Factors of Vitamin D Deficiency in Patients Scheduled to Undergo Revision Arthroplasty of the Hip, Knee and Shoulder-Data from a Single-Centre Analysis.

Vitamin D is crucial for ideal bone health and good muscle function, both essential requirements for successful joint arthroplasty. Hence, vitamin D deficiency has recently been identified as a predictor of poorer outcomes in patients scheduled to undergo total joint arthroplasty (TJA). Moreover, there is ample evidence today that vitamin D deficiency is associated with periprosthetic joint infection. Yet, vitamin D deficiency seems to be frequent in patients who are scheduled to undergo TJA. However, the prevalence of hypovitaminosis D in patients who require revision arthroplasty (rTJA) is largely unknown. Further, risk factors of vitamin D deficiency in these patients remain to be elucidated. For this reason, the primary objective of this study was to assess the vitamin D status of patients scheduled to undergo rTJA of the hip, knee and shoulder. The secondary objective was to identify potential risk factors for hypovitaminosis D in these patients. Serum vitamin D [25(OH)D] levels of 249 patients who were scheduled for rTJA were assessed over a period of twelve months at a high-volume TJA centre. Collectively, 23% of patients reported a routine intake of vitamin D supplements (58/249). Notably, 81% of patients (155/191) who did not report a routine vitamin D intake presented with insufficient vitamin D levels (below 30 ng/mL), while only 19% of patients (36/191) had sufficient vitamin D levels. Of those who reported a routine vitamin D intake, 75% (43/58) had sufficient vitamin D levels, while 25% (15/58) showed insufficient vitamin D status. Patients who did not routinely take any vitamin D supplements had significantly lower vitamin D levels compared to patients who reported regular vitamin D intake (19.91 ng/mL vs. 40.66 ng/mL). Further, BMI and nicotine abuse were identified as potential risk factors for hypovitaminosis D in patients without vitamin D supplementation. Moreover, the season of spring seems to be a risk factor in patients with vitamin D supplementation, while age itself did not appear to be a significant risk factor for low vitamin D levels. In conclusion, we found an alarmingly high rate of vitamin D deficiency in patients scheduled to undergo rTJA. Notably, reported routine vitamin D supplementation showed significantly increased serum vitamin D levels compared to patients with no reported supplementation. Due to the high prevalence of vitamin D deficiency, we believe that vitamin D status should routinely be assessed in patients who are scheduled to undergo rTJA.

Placing the tibial component of an ankle prosthesis: results of a CT-based simulation in healthy adults.

PURPOSE: To characterize the 3D geometry of the distal tibia resection area from healthy individuals using CT-based digital implantation for proper preoperative sizing of TAA tibia component placement. METHODS: Standardized CT images of healthy ankle joints serving as intra-individual references for treatment of contralateral injuries were identified. The tibial cross section dedicated to virtually host the tibial component was digitally prepared, and the size of the virtual contact surface was calculated. Finally, out of five prototypes the one fitting best in terms of size and alignment was identified. RESULTS: CT scans taken from 319 subjects were used for the virtual implantation procedure. Body height and size of the distal tibia contact area correlated (r = 0.49 and 0.42 in females and males, each p < 0.001). Prosthesis sizes 2 and 3 fit well for the vast majority of patients, while the smallest and largest sizes are rarely required. CONCLUSIONS: Digital implantation of the tibial component should be considered a valuable tool for preoperative planning as well as for the development of new implant types.

Zirconia ageing is related to total hip arthroplasty aseptic loosening. A study of 45 retrieved zirconia heads.

BACKGROUND: Y-TZP zirconia heads were recalled by the Food and Drug Administration (FDA) in 2001 and zirconia alone was no longer used in orthopedics. Tunnel furnace sintering was suspected of producing defects responsible for early material failure. As Zirconia Toughened Alumina (ZTA) matrices are widely used as bearing material and contain zirconia grains, there remains a need to better understand the in vivo ageing process of zirconia and its clinical implications when the material is produced by batch furnace sintering, the validated sintering process. QUESTIONS/OBJECTIVES: Is there an association between the ageing of batch furnace produced zirconia and THA revision? METHODS: 45 retrieved femoral heads, batch furnace sintered only, were analyzed. Roughness was measured by 3D profilometry, phase transfer by µRaman spectroscopy. Clinical data were compared with material characteristics. RESULTS: Irrespective of the cause of revision, all heads showed a crystallographic phase transition from tetragonal to monoclinic over 19.5%. A correlation was found between the phase change, roughness increase and aseptic loosening, with a threshold set at 24.5% of monoclinic phase. CONCLUSIONS: The ageing process of zirconia may lead to aseptic loosening, which, in the absence of contrary evidence, prohibits its use as the sole component of orthopedic materials. ZTA matrices should be clinically monitored, especially in young patients, and better in vitro modelling needs to be performed. LEVEL OF EVIDENCE: IV; Case series.

Cementless Versus Cemented Total Knee Arthroplasty of the Same Design: Shorter Operative Times and Minimal Differences in Early Outcomes.

Introduction: Modern primary cementless total knee arthroplasty (TKA) is increasingly popular, but there is limited evidence on its benefits, early complications, and failures. Purpose: We sought to evaluate operative time, early survivorship, and outcomes of cementless versus cemented TKA of the same design. Methods: As part of this single-center, multisurgeon, retrospective cohort study, we reviewed 598 primary, unilateral TKAs (170 cementless, 428 cemented) of the same design from 2016 to 2018. The cementless cohort was younger (63 vs 67 years) and had more cruciate-retaining implants (17% vs 12%) compared with the cemented cohort. We compared operative time, length of stay, and complications. Survivorship curves were generated via the Kaplan-Meier method. Results: Patients with cementless TKA (using the Triathlon implant, Stryker) had a 24% reduction in operative time (83 vs 109 minutes) but similar length of stay compared with those with cemented TKA (57 vs 61 hours). Cementless TKA had a higher rate of postoperative manipulation for stiffness compared with cemented TKA (8% vs 3%), but there were notable demographic differences between the cohorts. Despite 2 cases (1%) of early cementless tibial aseptic loosening requiring component revision compared with none in the cemented cohort, there was no difference in revision-free survivorship at 2 years (96% and 98%, respectively). Conclusion: This retrospective cohort study found that cementless TKA had a 24% reduction in operative time compared with cemented TKA and similar short-term survivorship. There was a slightly higher rate of aseptic revision and manipulation in the cementless cohort. Further study is warranted on the long-term durability of cemented and cementless TKAs to determine if cementless fixation proves more durable in the midterm to long term.

Nanoscale ZnO doping in prosthetic polymers mitigate wear particle-induced inflammation and osteolysis through inhibiting macrophage secretory autophagy.

Wear particles produced by joint replacements induce inflammatory responses that lead to periprosthetic osteolysis and aseptic loosening. However, the precise mechanisms driving wear particle-induced osteolysis are not fully understood. Recent evidence suggests that autophagy, a cellular degradation process, plays a significant role in this pathology. This study aimed to clarify the role of autophagy in mediating inflammation and osteolysis triggered by wear particles and to evaluate the therapeutic potential of zinc oxide nanoparticles (ZnO NPs). We incorporated ZnO into the prosthetic material itself, ensuring that the wear particles inherently carried ZnO, providing a targeted and sustained intervention. Our findings reveal that polymer wear particles induce excessive autophagic activity, which is closely associated with increased inflammation and osteolysis. We identified secretory autophagy as a key mechanism for IL-1ß secretion, exacerbating osteolysis. Both in vitro and in vivo experiments demonstrated that ZnO-doped particles significantly inhibit autophagic overactivation, thereby reducing inflammation and osteolysis. In summary, this study establishes secretory autophagy as a critical mechanism in wear particle-induced osteolysis and highlights the potential of ZnO-doped prosthetic polymers for targeted, sustained mitigation of periprosthetic osteolysis.

High Rates of Early Septic Failure, but Low Rates of Aseptic Loosening After Revision Total Knee Arthroplasty With Contemporary Rotating-Hinge Prostheses.

BACKGROUND: The purpose of this study was to determine implant survivorship and functional outcomes for revision total knee arthroplasty (rTKA) with contemporary rotating-hinge knee implants. METHODS: A retrospective review identified 115 rTKAs using contemporary rotating-hinge implants from 2014 to 2018 for the treatment of instability (34, 30%), reimplantation after periprosthetic joint infection (PJI) (33, 29%), aseptic loosening (25, 22%), arthrofibrosis (14, 12%), periprosthetic fracture (4, 3%), osteolysis (4, 3%), and femoral component fracture (1, 1%). There were 70 women (61%), and the mean age was 67 years (range, 27 to 94). The mean follow-up was 3 years (range, 2 to 6). Kaplan-Meier analysis and Cox proportional hazard models estimated survivorship. RESULTS: The re-revision rate was 20% (23 of 115) at an average of 18 months postoperatively. Re-revision indications included PJI (n = 14), aseptic loosening (n = 4), arthrofibrosis (n = 2), instability/malalignment (n = 1), femoral stem fracture (n = 1), and hinge mechanism disruption (n = 1). At 2 and 5 years, survivorship free from all-cause re-revision was 86 and 64%, and survivorship free from re-revision for aseptic loosening was 100 and 87%, respectively. Use of a rotating-hinge implant in reimplantation after PJI was a risk factor for subsequent re-revision (hazard ratio = 2.4, P = 0.046). On a radiographic review of unrevised rotating-hinges, there were major radiolucent lines around 2 femoral and 5 tibial components. The mean Knee Injury and Osteoarthritis Outcomes Score for Joint Replacement increased from 43 preoperatively to 60 at 1 year (P < 0.001). CONCLUSIONS: In patients treated with a rotating-hinge implant for rTKA, there were relatively poor 2-year (86%) and 5-year (64%) survivorship free from all-cause re-revision, most commonly due to PJI. Midterm survivorship free from re-revision for aseptic loosening was modest (87%). There should be a goal to mitigate complications in complex rTKAs with rotating-hinge implants, namely PJI.

Stem to prevent periprosthetic fracture after notching in total knee arthroplasty.

Improper osteotomy during total knee arthroplasty (TKA) can lead to anterior femoral notching, which increases the risk of periprosthetic fractures due to stress concentration. One potential solution is the addition of an intramedullary stem to the femoral component. However, the optimal stem length remains unclear. In this study, we aimed to determine the optimal stem length using finite element models. Finite element models of femurs were developed with unstemmed prostheses and prostheses with stem lengths of 50, 75, and 100 mm. Under squat loading conditions, the von Mises stress at the notch and stress distribution on four transversal sections of the femur were analyzed. Additionally, micromotion of the prosthesis-bone interface was evaluated to assess initial stability. The unstemmed prosthesis exhibited a von Mises stress of 191.8 MPa at the notch, which decreased to 43.1, 8.8, and 23.5 MPa for stem lengths of 50, 75, and 100 mm, respectively. The stress reduction on four selected femoral transversal sections compared with the unstemmed prosthesis was 40.0%, 84.4%, and 67.1% for stem lengths of 50, 75, and 100 mm, respectively. Micromotion analysis showed a maximum of 118.8 µm for the unstemmed prosthesis, which decreased significantly with the application of stems, particularly at the anterior flange. Intramedullary stems effectively reduced stress concentration at the femoral notch. The 50-mm stem length provided the optimal combination of reduced notch stress, minimized stress-shielding effect, and decreased micromotion at the anterior flange.

The use of a tibial stem in primary total knee arthroplasty for patients with a frontal deformity of more than ten degrees reduces the rate of postoperative pain.

BACKGROUND: The use of a tibial stem for large deformities (> 10°) would reduce the incidence of pain. The aim of this study was to compare the effect of tibial stem on postoperative pain and aseptic loosening at the tibia in patients with a preoperative deformity > 10° in the frontal plane at 2 years follow-up. METHODS: This was a retrospective single-center case-control study. Ninety-eight patients with deformities greater than 10° in the frontal plane and a BMI > 30 kg/m2 who had undergone posterior-stabilized (PS) total knee arthroplasty (TKA) with a tibial stem were matched using a propensity score to 98 patients who had undergone PS TKA without a tibial stem. The primary endpoint was the pain rate at 2 years. The secondary endpoints were the rate of aseptic loosening of the tibia at 2 years post-operatively. RESULTS: A significant difference was found in the rate of postoperative pain at 2 years. It was higher in the group without tibial stem compared with the group with tibial stem (41.8% vs 17.3%, p = 0.0003). In the group without tibial stem, 24.4% of pain was mild, 61% moderate and no severe pain. In the tibial stem group, 47.1% of pain was mild, 41.2% moderate and no severe pain. A radiolucent line (RLL) was present at 2 years in 26.5% of prostheses in the without tibial stem group and in 9.2% of prostheses in the tibial stem group (p = 0.002). There was no difference between the two groups in terms of aseptic loosening. CONCLUSION: The use of a tibial stem in primary TKA in patients with frontal deformities greater than 10° reduces postoperative pain and the presence of radiolucent lines.

Clinical outcomes and survival rates of a uncemented modular revision stem system in hip arthroplasty: a 10-year single-institution study on a frail population.

INTRODUCTION: The increasing prevalence of primary hip arthroplasty has led to a parallel rise in revision cases. Femoral revision often entails compromised bone integrity, requiring consideration of various solutions for optimal reconstructive options. Despite technological advancements, there is limited evidence on the clinical outcomes of the latest modular revision stems. This study aimed to evaluate the clinical outcomes and survival rates of next generation uncemented modular revision stem in patients undergoing hip revision surgery. MATERIALS AND METHODS: This retrospective single-center study assessed the survival and failure causes of a specific uncemented modular stem in 48 patients undergoing hip revision surgery between 2012 and 2022. Data included preoperative parameters, surgical details, and postoperative outcomes measured through clinical and radiographic assessments. Forty-eight patients (25 males, 23 females; mean age 72 years) were included, with a mean Charlson Comorbidity Index of 5. Preoperative diagnoses varied, with periprosthetic joint infection (PJI) being the most common (45.8%), followed by periprosthetic fractures (27.1%). Partial revisions occurred in 60.4%, total revisions in 39.6%. According to Paprosky classification of femoral bone loss, type II and III were the most represented, respectively 35.4% and 50%. RESULTS: At a mean follow-up of 4.6 years, stem survival was 92.5%. Complications (20%) included dislocation, PJI, fracture, and loosening; the overall reoperation rate was 12.5%. The SF-12 physical score was 43.6, while the mental score was 51.1. The HOOS score was 71.8, and the HHS score was 71.4. Radiographic analysis identified nonprogressive osteolysis in 15.1% of patients. CONCLUSIONS: This study on this uncemented modular revision stem demonstrated favorable outcomes in an elder fragile population with moderate to severe femoral bone loss. The implant's modularity provides versatility in addressing various defects, without any implant breakage observed during the study period. Literature comparison highlighted similar outcomes despite sample size differences. The promising results warrant continued investigation into the long-term survivorship of this modular stem system.

Weight-bearing pain and implant migration, progressive radiolucencies, radiolucency more than 2 mm and subsidence on radiographs and CT are generally accepted criteria for knee arthroplasty loosening: An international Delphi consensus study.

PURPOSE: Establishing the diagnosis of loosening in total or unicondylar knee arthroplasty remains a challenge with different clinical and radiological signs evaluated in study designs with high risk of bias, where few or incomplete criteria are formulated for establishing the diagnosis of implant loosening. This study aimed at evaluating the variability between different clinical and radiological criteria and establish a consensus regarding clinical and radiological criteria for the diagnosis of knee arthroplasty loosening. METHODS: Highly specialized knee surgeons focusing on revision arthroplasty were invited to take part in an international panel for a Delphi consensus study. In the first round, the participants were asked to state their most important clinical and radiological criteria for implant loosening. In a second round, the panel's agreement with the collected criteria was rated on a 5-point Likert scale (1-5). High variability was defined by receiving at least one score each indicating complete disagreement and complete agreement. Consensus was established when over 70% of participants rated a criterion as 'fully agree' (5) or 'mostly agree' (4). RESULTS: High variability was observed in 56% of clinical criteria and 38% of radiological criteria. A consensus was reached on one clinical (weight-bearing pain [82%]) and four radiological criteria, that is, implant migration, progressive radiolucencies, subsidence and radiolucencies >2 mm on X-ray or computed tomography (CT) (84%-100%). CONCLUSION: Amongst specialized knee revision surgeons, there is high variability in clinical and radiological criteria that are seen as important contributing factors to diagnosis of knee implant loosening. A consensus was reached on weight-bearing pain as clinical criterion and on implant migration, progressive radiolucencies, subsidence and radiolucencies of more than 2 mm on X-ray or CT as radiological criteria. The variability rates observed, along with the criteria that reached consensus, offer important insights for the standardization of diagnostic protocols. LEVEL OF EVIDENCE: Level V.

Excellent survival of second-generation uncemented dual mobility cups compared with first-generation cups at a minimum of 10 years follow-up in primary total hip arthroplasty.

INTRODUCTION: This study aimed to compare the revision rate and long-term survival between two generations of uncemented dual mobility cup (DMC) from the same manufacturer in primary total hip arthroplasty (THA) at a minimum follow-up of 10 years. METHODS: This retrospective monocentric study included all THA performed with an uncemented DMC from the same company. The cohort included 150 patients with 22 first-generation DMC and 128 second-generation DMC. The coating of the second generation was a double-coating Plasma spray of Titanium and Hydroxyapatite (HAP), compared to the coating of alumina and HAP for the first generation. The mean follow-up was 14.2 ± 1.2 years. The mean age was 76.0 ± 10.1 years. The Harris hip score (HHS), complications, and revisions were collected at the last follow-up. Ten- and fifteen-year Kaplan-Meier survival was calculated. RESULTS: At the last follow-up, the mean HHS was 83.2 ± 9.1. There were two acetabular loosenings with the old coating (9.1%) and one case with the new one (0.78%) (p = 0.056). There was one extra-prosthetic dislocation (0.67%) and one postoperative infection (0.67%). Survival without acetabular revision at 10 and 15 years was 90.9% for the 1st generation and 99.2% for the 2nd generation (p = 0.009). CONCLUSION: Survival without acetabular revision was significantly higher at 10 and 15 years of follow-up with the second generation of DMC with plasma-sprayed titanium and HAP coating compared to the first generation of DMC coat. The dislocation was uncommon, thanks to the dual mobility concept. This second generation of uncemented DMC can be safely used in primary THA.

Comparative analysis of femoral bone loss: uncemented vs. cemented aseptic stem loosening in first-time revision surgery-a retrospective evaluation of 215 patients.

INTRODUCTION: The integrity of the femoral bone is crucial when considering reconstructive options for the first-time revision of a total hip arthroplasty (THA). Aseptic loosening of primary stems, whether cemented or uncemented, significantly affects the volume and quality of resultant femoral bone loss. This study evaluates the impact of the initial fixation method on femoral bone defect patterns by comparing the extent of bone loss. MATERIALS AND METHODS: A retrospective cohort of 215 patients with either cemented or uncemented stems, indicated for aseptic stem loosening, and undergoing first-time stem revision from 2010 to 2022 at our institution was analyzed. Femoral bone loss extent at first-time revision was preoperatively gauged using radiographs and categorized by the Paprosky classification. Survival probabilities pre-first-time revision for both stem types were calculated using Kaplan-Meier methods. Hazard ratios were applied to compare the risk of initial revision for uncemented versus cemented stems within the first and subsequent 2nd to 10th years post-primary implantation. RESULTS: Cemented stems were associated with a higher occurrence of significant bone defects of type 3a (23.53% vs. 14.02%, p = .108), 3b (39.22% vs. 1.22%, p < .001), and 4 (3.92% vs. 0.00%) compared to uncemented stems. Conversely, smaller defects of type 1 and 2 were more prevalent in uncemented stem loosening (84.76% vs. 33.33%, p < .001). Notably, cemented stems exhibited a significantly prolonged revision-free period over the complete decade following primary insertion (p < .001). The unadjusted risk of first-time revision due to stem loosening showed a tendency to an increase in uncemented stems within the initial postoperative year (HR 5.55, 95% CI 0.74; 41.67, p = .096), and an adjusted risk of 2.1 (95% CI 0.26; 16.53, p = .488). However, these differences did not reach statistical significance. In the subsequent 2nd-10th years, the risk was lower compared to cemented stems (HR 2.35, 95% CI 1.39; 3.99, p = .002). CONCLUSIONS: Uncemented primary stems necessitating first-time revision due to aseptic loosening demonstrated notably smaller femoral bone defects in comparison to primary cemented stems.

Current Evidence Does Not Support the Use of Tibial Stem Extension in Total Knee Arthroplasty of Obese Patients: A Systematic Review.

BACKGROUND: Obesity rates have been increasing globally, leading to a higher incidence of knee osteoarthritis and a surge in primary and revision total knee arthroplasty (TKA). The debate continues on the impact of obesity on TKA success, particularly regarding the use of stemmed tibial components in obese patients. This systematic review aimed to compare the effectiveness of stemmed tibial components versus standard keeled tibial components in obese patients undergoing TKA. METHODS: A systematic review was conducted using databases including PubMed, Embase, Scopus, and Web of Science from inception to December 2023. The eligibility criteria were Participants: Patients who have obesity undergoing TKA; Intervention: stemmed TKA; Comparator: standard keeled tibial TKA; Outcomes: aseptic loosening, patient-reported outcome measures (PROMs), and overall revision. Data extraction and quality assessment were performed using the Newcastle-Ottawa Scale for cohort studies and the Cochrane risk-of-bias tool for randomized trials. RESULTS: The search yielded 470 studies, with 10 studies (42,533 knees) meeting the inclusion criteria. These studies included 3 randomized controlled trials and 7 retrospective cohorts. The primary outcomes measured were aseptic loosening and overall revision rates, while secondary outcomes included PROMs. Results indicated mixed findings, with some studies suggesting improved outcomes with stemmed components in cases of aseptic loosening and mechanical failure, while others showed no significant difference. The PROMs did not show a significant difference between groups post-TKA. The certainty of the evidence was graded as "very low" using the Grading of Recommendations, Assessment, Development, and Evaluations framework. CONCLUSIONS: Current literature does not provide conclusive evidence to support the routine use of stemmed tibial components in TKA for obese patients. The decision to use stem extensions should not solely rely on the patient's obesity status. Further high-quality studies are needed to clarify the role of stemmed components in TKA for this patient population. LEVEL OF EVIDENCE: III.

Assessing the impact of distal femoral morphology using Citak's ratio: an independent risk factor for aseptic loosening in rotating hinge knee prosthesis.

BACKGROUND: Aseptic loosening (AL) is a frequent complication after rotating hinge knee (RHK) prosthesis. Citak's ratio has recently been developed to describe and classify distal femoral morphology into 3 groups (A, B, C). It consists in a ratio between the diameters of the femoral canal at 20 cm from the knee joint line and at 2 cm from the adductor tubercle. The objective of the study was to identify whether the femoral distal anatomical shape described with this ratio represents a risk factor for AL in RHK prosthesis. METHODS: Retrospective study of patients who had undergone primary or revision RHK prosthesis, with a follow-up of minimum 4 years. Citak's ratio was calculated, and patients were classified depending on its value. Univariate and bivariate statistical analysis was performed to identify AL risk factors. Receiver Operating Characteristics (ROC) analyses were conducted to examine diagnostic quality of the parameters of interest. RESULTS: Thirty-three patients were included. Most of them females (ratio 26:7), with a mean age of 78.2 (SD 6.9). Three patients presented AL (rate of 9%), all of them classified into group C (100%). Citak's ratio was significantly related to the AL rate (p < 0.001), and so was the femoral canal diameter at 20 cm from the knee joint (p 0.010). The ROC curve analysis yielded an Area Under the Curve (AUC) of 0.922 (CI 95% 0.819-1.000) for the Citak´s ratio. CONCLUSION: The inner femoral diameter at 20 cm proximal to the knee joint line and Citak's ratio help indentify patients at risk of AL after RHK prosthesis, and thus a better planning of the surgery.

Comparison of early and late aseptic baseplate failure in primary reverse shoulder arthroplasty with and without structural glenoid autograft.

BACKGROUND: Early reverse total shoulder arthroplasty (RTSA) designs demonstrated high glenoid baseplate complication and revision rates. Although contemporary designs have reduced the incidence of glenoid baseplate failures, there are reports of elevated failure risks in RTSA with glenoid bone grafting within the first 2 years. This study aims to evaluate the incidence and etiology of aseptic glenoid baseplate failure with a contemporary central screw baseplate. The null hypothesis is that majority of the baseplate failure occurs within the first 2 years and that use of glenoid bone grafting does not lead to a higher risk of baseplate failure. METHODS: In 2014-2019, a total of 753 consecutive patients who underwent primary RSA using the same inlay press-fit humeral stem and monoblock central screw baseplate were retrospectively reviewed. Fracture and septic arthropathy cases were excluded. All patients underwent preoperative radiographic and computed tomographic evaluation. If there was significant glenoid erosion (Walch A2, B2, B3, C1, C2, E2, E3, and/or E4 variants), patient-specific structural glenoid bone grafting was performed. All patients underwent standardized radiographic follow-up, and failure was strictly defined as any hardware breakage and/or shift in glenoid baseplate position. Failures were defined as "early" if occurring within 2 years and "late" if occurring >2 years after surgery. Comparative analysis was performed to evaluate demographics, glenoid graft use, and graft union rates between the cohorts. RESULTS: There were 23 patients with baseplate failures (23 of 753, 3.0%) at a mean of 23 months. Twenty-two failures (96%) occurred in patients who received structural glenoid bone grafting. Only 1 failure (0.2%) occurred when bone grafting was not indicated (P < .001). The most common failure pattern was associated with the B2 glenoid (16 of 23, 70%). There were 5 early failures (22%) and 18 late failures (78%). There were no differences in any patient demographic characteristics between cohorts. All 5 early failures had graft nonunion, and 4 of them occurred without trauma. In the 18 late failures, 9 (50%) occurred without trauma (P = .135). Seventeen of these patients had glenoid grafting, among which 9 (53%) had graft nonunion. CONCLUSIONS: Contemporary RTSA glenoid baseplate designs have an acceptably low incidence of failure. However, the addition of structural bone graft to correct glenoid wear leads to higher aseptic baseplate failure rate. The majority of these patients suffer failure after the 2-year postoperative mark, highlighting the necessity of longer follow-up. Further analysis is necessary to quantify glenoid characteristics (severity of glenoid erosion, critical size of graft) associated with failure.