Fenestrated Endovascular Repair With Large Device Diameters (34-36 mm) is Associated With Type 1 and 3 Endoleak and Reintervention.

BACKGROUND: Patients with abdominal aortic aneurysms undergoing EVAR with larger device diameters (34-36 mm) have worse outcomes due to proximal fixation failure and need for reintervention. We examine outcomes relating to standard fenestrated repair (FEVAR) with larger device diameters, and investigate whether a similar relationship exists. METHODS: Retrospective review of a prospectively maintained, single institution database of patients treated with the Cook ZFEN device between 2012-2017. Outcomes were stratified by device diameter into normal-diameter (ND,≤ 32 mm) and large-diameter (LD,34-36 mm). Primary endpoints were need for reintervention and composite type I/III endoleak. RESULTS: One-hundred consecutive patients treated were identified for inclusion. Overall mean age was 73.6 years and mean aortic diameter was 59.1 mm. Mean follow-up was 22 months. A total of 26 (26%) patients were treated with LD devices. Number of target vessels per patient was 2.8 in both groups. Infrarenal neck length and diameter were significantly different in the LD and ND patients, respectively (2.6 mm vs. 4.7 mm (P < 0.01) and 30.1 mm vs. 23.4 mm (P < 0.01)). Percent graft oversizing was lower in the LD cohort (19% vs. 24%; P = 0.006). No difference was seen in overall mortality at 30-days (0% vs. 2%; P = 0.4) or at latest follow up (6% vs. 14%; P = 0.6). Reinterventions were not significantly different at 30 days, but were significantly higher over the follow-up period in the LD cohort (46.2 vs. 17.6%; P = 0.002). LD diameter was associated with reintervention on univariate (HR 1.19, 95% CI 1.04-1.37), but not multivariate analysis. The composite endpoint of type I/III endoleak was higher in the LD cohort (15.4% vs. 2.7%; P = 0.004). CONCLUSIONS: FEVAR requiring 34- or 36-mm device diameters is associated with an increased risk of composite type I/III endoleak and reintervention. Patients undergoing fenestrated repair requiring LD devices should be closely monitored, with consideration for proximal or open repair.

The influence of bearing surfaces on revisions due to dislocations in total hip arthroplasty.

INTRODUCTION: Recurrent dislocations are still the most frequent reason for revision in total hip arthroplasty (THA). The impact of bearing surfaces on dislocations is still controversial. We hypothesized that: (1) bearing surfaces influence the revisions due to dislocations; (2) ceramic-on-ceramic reduced the revisions for dislocations in adjusted models; (3) Delta-on-Delta bearings reduced the revisions for dislocations in comparison to surfaces with cross-linked polyethylene. MATERIALS AND METHODS: The regional arthroplasty registry was enquired about bearing surfaces and revisions for dislocations and instability. Unadjusted and adjusted rates were provided, including sex, age (<65 years or ≥65 years), head diameter (≤28 mm or >28 mm; <36 mm or ≥36 mm) as variables. 44,065 THAs were included. RESULTS: The rate of revisions for dislocations was significantly lower in ceramic-on-ceramic and metal-on-metal bearings (unadjusted rates). After adjusting for age, sex, and head size (36 and 28 mm), hard-on-hard bearings were protective (p < 0.05): ceramic-on-ceramic had a lower risk of revisions due to dislocation than ceramic-on-polyethylene (HR 1.6, 95% CI 1.2-2.2 p = 0.0009). The rate of revisions for dislocation was similar in bearings with cross-linked polyethylene and Delta-on-Delta articulations, in unadjusted and adjusted models. CONCLUSION: Bearings with conventional polyethylene were more predisposed to dislocations. Currently adopted bearings exerted no significant influence on revisions due to dislocations. These findings could be primarily related to wear, but due to the time distribution, soft tissue envelopes and surface tension may also play a role. Pre-clinical biomechanical evaluations and prospective matched cohort studies are required to draw definitive conclusions.

Reduction of Periprosthetic Proximal Femur Fracture in Direct Anterior Total Hip According to Stem Design.

The direct anterior approach (DAA) is gaining popularity in primary total hip arthroplasty (THA). Although DAA has demonstrated many advantages over other surgical approaches, periprosthetic femur fractures (PPFF) rates continue to be higher. Femoral stem designs that allow for easier insertion via a DAA may contribute to the higher rates of fracture seen in this approach. Certain stem designs and fixation methods may reduce the risk of PPFF via a DAA in primary THA.

Modular or Monolithic Tapered Fluted Prostheses for Periprosthetic Fractures: Which One Could Work for You?

Periprosthetic fracture around a femoral component is a potentially devastating complication after total hip arthroplasty. Surgical treatment is often technically demanding and requires a thorough understanding of fracture care and revision joint reconstruction. Advancements in femoral component designs for revision total hip arthroplasty have improved management of this challenging complication. It is important for surgeons to understand which femoral component design might best suit their needs. We present an overview of revision total hip arthroplasty in the setting of periprosthetic fracture, focusing on comparing the 2 most popular femoral component revision models, the modular and monolithic tapered fluted conical prostheses.

Impact of Coronary Stent Design in Proximal Balloon Edge Dilation Technique for Bifurcation Percutaneous Coronary Intervention.

The proximal optimizing technique (POT) -proximal balloon edge dilation (PBED) sequence for side branch (SB) dilatation with cross-over single-stent implantation decreases both strut obstruction at the SB ostium and stent deformation at the main branch (MB).The purpose of this experimental bench test was to assess the impact of stent design on stent deformation, obstruction by stent struts at a jailed SB ostium, and stent strut malapposition in the POT-PBED sequence.Fractal coronary bifurcation bench models (60- and 80-degree angles) were used, and crossover single-stent implantation (3-link stent: XIENCE Sierra, Abbott Vascular, Santa Clara, CA, n = 10; 2-link stent: Synergy, Boston Scientific, Marlborough, MA, n = 10) was performed from the MB using the POT-PBED sequence. Jailing rates at the SB ostium, stent deformation, and stent strut malapposition of the bifurcation segment were assessed using videoscopy and optical coherence tomography.After SB dilatation using the PBED technique, jailing rates at the SB ostium and stent deformation did not differ significantly between the two types of stents. Conversely, the rate of malapposed struts of the bifurcation segment after the PBED procedure was significantly lower with 3-link stents than with 2-link stents for both 60- and 80-degree angles (60-degree angle: 4.3% ± 4.4% versus 22.0% ± 11.1%, P = 0.044; 80-degree angle: 20.8% ± 15.1% versus 57.2% ± 17.0%, P < 0.001, respectively).In the POT-PBED sequence, 3-link stents might be a preferable coronary bifurcation stent, maintaining a jailed SB ostium while significantly reducing stent strut malapposition of the bifurcation segment when compared with 2-link stents.

Adverse Local Tissue Reactions are Common in Asymptomatic Individuals After Hip Resurfacing Arthroplasty: Interim Report from a Prospective Longitudinal Study.

BACKGROUND: The evaluation of the natural history prevalence of adverse local tissue reactions (ALTRs) using MRI has focused only on metal-on-metal (MoM) bearing surfaces without comparison to nonMoM bearing surfaces. QUESTIONS/PURPOSES: To determine (1) the longitudinal changes and differences in blood metal ion levels in patients with hip resurfacing arthroplasty (HRA), ceramic-on-ceramic (CoC) THA, and metal-on-polyethylene (MoP) THA compared with those undergoing ceramic-on-polyethylene (CoP) THA; (2) how the longitudinal change of synovial reaction classification in patients with HRA, CoC THA, and MoP THA compares with those undergoing CoP THA, and whether there is an association between the presence of an ALTR or metallosis on MRI with corresponding patient-reported outcomes, or the presence of capsular dehiscence; and (3) differences in blood metal ion levels between patients undergoing HRA with an ALTR or metallosis on MRI and those with HRA without these conditions. METHODS: Between March 2014 and February 2019, 22,723 patients underwent primary HRA and THA at one center. Patients received an HRA based on their desired athletic level after surgery and the presence of normal acetabular and proximal femoral bone morphology without osteopenia or osteoporosis. Two percent (342 of 22,723) of patients were contacted to participate, and 71% (243 of 342 hips in 206 patients) were enrolled for analysis at baseline. The patients underwent arthroplasty for degenerative joint disease, and 25 patients withdrew over the course of the study. We included patients who were more than 1 year postarthroplasty. All participants had an MRI examination and blood serum ion testing and completed a Hip Disability and Osteoarthritis Outcome Score survey annually for four years (baseline, year 1, year 2, year 3). Morphologic and susceptibility-reduced MR images were evaluated by a single radiologist not involved in the care of patients for the presence and classification of synovitis (Gwet AC1: 0.65 to 0.97), synovial thickness, and volume (coefficient of repeatability: 1.8 cm3). Linear mixed-effects models were used to compare the mean synovial thickness, synovial volume, and Hip Disability and Osteoarthritis Outcome Score subscales between bearing surfaces at each timepoint and within each bearing surface over time. Marginal Cox proportional hazards models were used to compare the time to and the risk of developing ALTR only, metallosis only, and ALTR or metallosis between bearing surfaces. All models were adjusted for age, sex, BMI, and length of implantation based on known confounders for hip arthroplasty. Adjustment for multiple comparisons was performed using the Dunnett-Hsu method. RESULTS: Patients with unilateral HRA had higher cobalt and chromium serum ion levels (baseline: 1.8 ± 0.8 ppb, year 1: 2.0 ± 1.5 ppb, year 2: 2.1 ± 1.2 ppb, year 3: 1.6 ± 0.7 ppb) than those with unilateral CoP bearings (baseline: 0.0 ± 0.1 ppb, year 1: 0.1 ± 0.3 ppb, year 2: 0.0 ± 0.2 ppb, year 3: 0.0 ± 0.0 ppb) at all timepoints (p < 0.001 for each time point). More patients who received an HRA developed ALTR or metallosis on MRI than did patients with CoP bearings (hazard ratio 4.8 [95% confidence interval 1.2 to 18.4]; p = 0.02). There was no association between the longitudinal change of synovial reaction to ALTR or metallosis on MRI with patient-reported outcomes. In addition, there was no association between the presence of dehiscence at baseline and the subsequent development of ALTR or metallosis, as seen on MRI. There were elevated cobalt (4.7 ± 3.5 ppb) and chromium (4.7 ± 2.6 ppb) serum levels in patients with unilateral HRA who had an ALTR or metallosis present on MRI at year 1 compared with patients without an ALTR or metallosis on MRI (cobalt: 1.8 ± 1.0 ppb, mean difference 4.7 ppb [95% CI 3.3 to 6.0]; p < 0.001; chromium: 2.3 ± 0.5 ppb, mean difference 3.6 ppb [95% CI 2.2 to 5.0]; p < 0.001) as well as for chromium at year 3 (3.9 ± 2.4 ppb versus 2.2 ± 1.1 ppb, mean difference 1.3 ppb [95% CI 0.3 to 2.4]; p = 0.01). CONCLUSION: We found a higher proportion of ALTR or metallosis on MRI in patients with HRA compared with patients with CoP, even when patient self-assessed symptomatology of those with an ALTR or metallosis on MRI was not different than the absence of these features. MRI detected ALTRs in high-function patients, emphasizing that an annual clinical assessment dependent on survey or blood ion testing alone may not detect soft tissue complications. The results of this study are in line with prior consensus recommendations of using MRI as part of a routine follow-up protocol for this patient population. LEVEL OF EVIDENCE: Level III, therapeutic study.

Are Damage Modes Related to Microstructure and Material Loss in Severely Damaged CoCrMo Femoral Heads?

BACKGROUND: Fretting and corrosion in metal-on-polyethylene total hip arthoplasty (THA) modular junctions can cause adverse tissue reactions that are responsible for 2% to 5% of revision surgeries. Damage within cobalt-chromium-molybdenum (CoCrMo) alloy femoral heads can progress chemically and mechanically, leading to damage modes such as column damage, imprinting, and uniform fretting damage. At present, it is unclear which of these damage modes are most detrimental and how they may be linked to implant alloy metallurgy. The alloy microstructure exhibits microstructural features such as grain boundaries, hard phases, and segregation bands, which may enable different damage modes, higher material loss, and the potential risk of adverse local tissue reactions. QUESTIONS/PURPOSES: In this study, we asked: (1) How prevalent is chemically dominated column damage compared with mechanically dominated damage modes in severely damaged metal-on-polyethylene THA femoral heads made from wrought CoCrMo alloy? (2) Is material loss greater in femoral heads that underwent column damage? (3) Do material loss and the presence of column damage depend on alloy microstructure as characterized by grain size, hard phase content, and/or banding? METHODS: Surgically retrieved wrought CoCrMo modular femoral heads removed between June 2004 and June 2019 were scored using a modified version of the Goldberg visually based scoring system. Of the total 1002 heads retrieved over this period, 19% (190 of 1002) were identified as severely damaged, exhibiting large areas of fretting scars, black debris, pits, and/or etch marks. Of these, 43% (81 of 190) were excluded for metal-on-metal articulations, alternate designs (such as bipolar, dual-mobility, hemiarthroplasty, metal adaptor sleeves), or previous sectioning of the implant for past studies. One sample was excluded retroactively as metallurgical analysis revealed that it was made of cast alloy, yielding a total of 108 for further analysis. Information on patient age (57 ± 11 years) and sex (56% [61 of 108] were males), reason for removal, implant time in situ (99 ± 78 months), implant manufacturer, head size, and the CoCrMo or titanium-based stem alloy pairing were collected. Damage modes and volumetric material loss within the head tapers were identified using an optical coordinate measuring machine. Samples were categorized by damage mode groups by column damage, imprinting, a combination of column damage and imprinting, or uniform fretting. Metallurgical samples were processed to identify microstructural characteristics of grain size, hard phase content, and banding. Nonparametric Mann-Whitney U and Kruskal-Wallis statistical tests were used to examine volumetric material loss compared with damage mode and microstructural features, and linear regression was performed to correlate patient- and manufacturer-specific factors with volumetric material loss. RESULTS: Chemically driven column damage was seen in 48% (52 of 108) of femoral heads, with 34% (37 of 108) exhibiting a combination of column damage and imprinting, 12% (13 of 108) of heads displaying column damage and uniform fretting, and 2% (2 of 108) exhibiting such widespread column damage that potentially underlying mechanical damage modes could not be verified. Implants with column damage showed greater material loss than those with mechanically driven damage alone, with median (range) values of 1.2 mm3 (0.2 to 11.7) versus 0.6 mm3 (0 to 20.7; p = 0.03). Median (range) volume loss across all femoral heads was 0.9 mm3 (0 to 20.7). Time in situ, contact area, patient age, sex, head size, manufacturer, and stem alloy type were not associated with volumetric material loss. Banding of the alloy microstructure, with a median (range) material loss of 1.1 mm3 (0 to 20.7), was associated with five times higher material loss compared with those with a homogeneous microstructure, which had a volume loss of 0.2 mm3 (0 to 4.1; p = 0.02). Hard phase content and grain size showed no correlation with material loss. CONCLUSION: Chemically dominated column damage was a clear indicator of greater volume loss in this study sample of 108 severely damaged heads. Volumetric material loss strongly depended on banding (microstructural segregations) within the alloy. Banding of the wrought CoCrMo microstructure should be avoided during the manufacturing process to reduce volumetric material loss and the release of corrosion products to the periprosthetic tissue. CLINICAL RELEVANCE: Approximately 30% of THAs rely on wrought CoCrMo femoral heads. Most femoral heads in this study exhibited a banded microstructure that was associated with larger material loss and the occurrence of chemically dominated column damage. This study suggests that elimination of banding from the alloy could substantially reduce the release of implant debris in vivo, which could potentially also reduce the risk of adverse local tissue reactions to implant debris.

Malalignment and distal contact of short tapered stems could be associated with postoperative thigh pain in primary total hip arthroplasty.

PURPOSE: Short tapered stem placement has been extensively employed in total hip arthroplasty (THA). Suboptimal fixation tends to cause postoperative complications, such as thigh pain. However, it remains unclear whether poor seating/alignment of short tapered stems contributes to thigh pain. In this study, we retrospectively examined the factors that might be associated with thigh pain. METHODS: Medical records of 230 patients who had undergone THAs at our hospital were reviewed retrospectively. All patients received the same mediolateral (ML) short tapered femoral stems. The association between thigh pain and patients' demographics, radiographic findings, or the type of fitting of the femoral stems was investigated. RESULTS: In our cohort, 68 patients (27.8%) presented with thigh pain. Among 203 type I fit patients, 62 (30.5%) developed thigh pain, while only 6 out of 43 (12.2%) type II fit patients had thigh pain, with the differences being statistically significant (x2 = 6.706, p = 0.01). In addition, hip anteroposterior radiographs exhibited that the stem angulation (mean 2.52°), the variation in angulation (mean 1.32°), and the extent of femoral stem subsidence (mean 0.29 cm) were greater in patients with thigh pain than in their counterparts without thigh pain (all p < 0.05). CONCLUSION: Malalignment and improper seating of short tapered stems could be at least one of the reasons for post-THA thigh pain. The distal contact between the stem tip and the medial femoral cortex might result in thigh pain. Our study suggested that distal implant contact should be avoided, and stem alignment should be meticulously performed in the placement of ML short tapered femoral stems for THA.

"Pumpology": the Realistic Issues Associated with Pump Placement in Prosthetic Surgery.

PURPOSE OF REVIEW: The goal of this paper was to discuss the issues and/or overt complications associated with the 3-piece inflatable penile prosthesis (3-IPP) pump. We also addressed how to resolve such issues with or without surgical intervention. RECENT FINDINGS: Numerous modifications of the 3-IPP pump have been introduced with multiple techniques to place the pump. These are largely dependent on the approach to place the 3-IPP. Pump issues may inevitably occur, and there are numerous special maneuvers that can be performed to resolve pump issues. It is important for urologists to know maneuvers for pump malfunctions to prevent unnecessary surgical procedures and pump revision. Several studies are reviewed regarding pump issues and patient satisfaction; however, a more structured prospective research project is warranted to further evaluate these issues.

Reduction of stent-associated morbidity by minimizing stent material: a prospective, randomized, single-blind superiority trial assessing a customized 'suture stent'.

OBJECTIVES: To compare a customized 'suture stent' with a standard ureteric stent regarding stent-related symptoms, safety and efficacy. MATERIALS AND METHODS: Patients with urolithiasis located proximal to the iliac vessel crossing, requiring stenting in preparation for secondary ureterorenoscopy (URS) were randomized to standard ureteric stenting or a suture stent. Secondary ureterorenoscopy was performed 2-6 weeks later. The Ureteral Stent Symptoms Questionnaire (USSQ) was completed after 1 week, on the day before URS and 2-6 weeks after stent removal. Stent efficacy and safety were systematically assessed. RESULTS: A total of 88 patients were included in the analysis. The median (range) suture stent length was 10 (5-25) cm vs 26 cm for standard stents. Operation time was longer for insertion of the suture stent (24.0 vs 14.5 min; P < 0.001). Patients with a suture stent had a significantly lower USSQ urinary symptoms score 1 week after stent insertion, adjusted for baseline symptoms by subtracting scores from the final visit without indwelling stent (mean 7.1 vs 13.7, difference -6.6, 95% confidence interval [CI] -3.4 to -9.8; P < 0.001). Prior to secondary URS (after 2-6 weeks), baseline-adjusted urinary symptoms (mean 4.7 vs 12.2, difference -7.5, 95% CI -4.5 to -10.4; P < 0.001) and pain subscores (11.5 vs 17.6, difference -6.1, 95% CI -0.7 to -11.6; P = 0.004) were significantly lower in the suture stent group. All other USSQ subscores showed no significant differences. Adverse events occurred in 15 patients and were similarly frequent in the two groups. No significant differences were found between the groups regarding ureteric access during secondary URS. CONCLUSION: Replacement of the distal part of ureteric stents by a suture can reduce stent-associated symptoms without restrictions regarding secondary stone removal or safety.

Damage patterns in polyethylene fixed bearings of retrieved total ankle replacements.

INTRODUCTION: Poor long-term outcomes continue to hinder the universal adoption of total ankle replacements (TAR) for end stage arthritis. In the present study, polyethylene inserts of TARs retrieved at revision surgery were analyzed for burnishing, scratching, mechanical damage, pitting, and embedded particles. METHODS: Fourteen retrieved polyethylene inserts from a fixed bearing total ankle replacement design currently in clinical use were analyzed. Duration of time in vivo was between 11.5 months and 120.1 months. Three investigators independently graded each articular surface in quadrants for five features of damage: burnishing, scratching, mechanical damage, pitting, and embedded particles. RESULTS: No correlation was found for burnishing between the anterior and posterior aspects (p = 0.47); however, scratching and pitting were significantly higher on the posterior aspect compared to the anterior aspect (p < 0.03). There was a high correlation between burnishing and in vivo duration of the implant (anterior: R = 0.67, p = 0.01, posterior: R = 0.68, p = 0.01). CONCLUSION: The higher concentration of posterior damage on these polyethylene inserts suggested that prosthesis-related (design) or surgeon-related (technique) factors might restrict the articulation of the implant. The resulting higher stresses in the posterior articular surfaces may have contributed to the failure of retrieved implants Keywords: Retrieval, Polyethylene Damage, Total Ankle Replacement.

The Role of Stem Modularity in the Failure of Internal Fixation in Geriatric Patients With Distally Fixed Hemiarthroplasty.

The aim of this study was to compare the radiological and clinical outcomes of the same make of modular and monoblock tapered fluted stems in patients with failure of internal fixation following osteoporotic intertrochanteric fracture. This retrospective, comparative study included patients older than 65 years who underwent hemiarthroplasty with a modular or monoblock distally fixed fluted stem and had failed treatment with proximal femoral nailing between 2012 and 2017, with at least a 2-year follow-up period. Radiographic and clinical evaluations of the groups were compared. The modular group comprised 22 males and 18 females with a mean age of 85.05±7.1 years, and the monoblock group comprised 27 males and 17 females with a mean age of 83.27±7.0 years. No significant difference was observed between the groups regarding the preoperative and final-visit Harris Hip Score and Parker and Palmer Mobility Score values (P>.05 for both). More patients showed osseous restoration in the monoblock group, but not to a significant level. The groups were similar regarding mortality rates. Stem length was greater in the modular group, but the proximal femoral part and stem size were similar in the groups (P<.05 for all). Canal filling at levels A, B, and C was negatively correlated (weak) with the proximal femoral bone restoration (P<.001 for all). Canal filling at level B was negatively correlated (weak) with the stress shielding of the femur (P<.05 for all). When comparing the modularity of the stem by minimizing the variations of both prostheses, such as brand and geometric design, there was no significant difference in either clinical or radiological evaluations. [Orthopedics. 2021;44(1):e119-e124.].

Influence of Femoral Component Design on Proximal Femoral Bone Mass After Total Hip Replacement: A Randomized Controlled Trial.

BACKGROUND: In this randomized controlled trial (RCT), we compared bone remodeling and bone turnover between 2 total hip arthroplasty implants-the short, proximally porous-coated Tri-Lock Bone-Preservation Stem and a conventional, fully-coated Corail prosthesis-over a 2-year postoperative period. METHODS: Forty-six participants received the Tri-Lock prosthesis and 40 received the Corail prosthesis. At baseline, the 2 groups had similar demographics, proximal femoral bone mineral density (BMD), bone turnover markers, radiographic canal flare index, and patient-reported outcome measure (PROM) scores. Outcomes were measured at weeks 26, 52, and 104. RESULTS: Loss of periprosthetic bone, measured by high-sensitivity dual x-ray absorptiometry region-free analysis (DXA-RFA), was identified at the calcar and proximal-lateral aspect of the femur in both prosthesis groups (p < 0.05). However, the conventional prosthesis was associated with a smaller reduction in BMD compared with the bone-preservation prosthesis (p < 0.001). This effect was most prominent in the region of the femoral calcar and greater trochanter. A small gain in BMD was also identified in some areas, and this gain was greater with the conventional than the bone-preservation prosthesis (p < 0.001). The 2 groups had similar changes in bone turnover markers and improvement in PROM scores over the study period (p > 0.05). The adverse-event rate was also similar between the groups (p > 0.05). CONCLUSIONS: This RCT shows that prostheses intended to preserve proximal femoral bone do not necessarily perform better in this regard than conventional cementless designs. DXA-RFA is a sensitive tool for detecting spatially complex patterns of periprosthetic bone remodeling. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Three-dimensional kinematic analysis of dislocation mechanism in dual mobility total hip arthroplasty constructs.

Dual mobility (DM) total hip arthroplasty (THA) is associated with reduced dislocation rates; however, the kinematic mechanism of dislocation in DM THA constructs is still not well understood. This study hypothesizes that the difference in kinematics between DM THA and conventional THA designs contributes to reduced dislocation rates of DM THA. In addition, this study aims to quantify and compare those kinematic parameters between DM THA and conventional THA using a validated dual fluoroscopy imaging system (DFIS) and finite element (FE) modelling. Fresh frozen cadavers were measured to compare the impingement-free range of motion and provocative subluxation kinematics among three THA constructs: (1) DM, (2) constrained liner (CS), and (3) 36 mm head diameter neutral liner (NL). The DFIS was used to measure the in vitro kinematics of the hip. Subject-specific FE models were developed to assess the horizontal dislocation distance and resistive torque at dislocation. The DM construct head exhibited increased provocative anterior and posterior subluxation range of motion before dislocation when compared to CS constructs (p = .05; p = .03), as well as NL constructs (p = .05). The DM THA showed a significantly larger posterior horizontal dislocation distance, as well as smaller resistive torque at dislocation, when compared to NL (p = .05; p = .03) and CS constructs (p = .04; p = .01). Our findings demonstrate there was increased provocative subluxation range of motion as well as normalized jump distance for the DM constructs compared to the NL and CS constructs, suggesting the DM THA may provide increased stability hip during at-risk functional hip positions.

Impingement Between the Metal Stem and the Ceramic Liner in Total Hip Arthroplasty: The Neck Is Not the Only Place Where Impingement Occurs.

BACKGROUND: It is assumed that impingement between the ceramic liner and the stem increases the possibility of a liner fracture in total hip arthroplasty with a ceramic-on-ceramic bearing. The purpose of this study was to analyze the pattern of the impingement by evaluating the notches (U-shaped indented wear scars engraved on the stem) on radiographs to determine when and where impingement develops and to analyze the factors affecting its occurrence. METHODS: Among the primary total hip arthroplasty cases using a ceramic-on-ceramic bearing performed from November 1997 to December 2003, 244 cases of 197 patients (123 male patients and 74 female patients) that had follow-up of ≥15 years were included. All of the radiographs were examined with special regard to the notches and the cup positions. RESULTS: Notches were detected at 77 sites of 57 cases (23.4%) for the first time between 8 months and 14.8 years after the surgical procedure. They were located on the neck or the shoulder of the stem. Shoulder notches were detected only in the cases with a short-neck head. Shoulder notches were found in 29 cases (20.0% of short-neck cases). Cup inclination was lower (p = 0.01) and anteversion was higher (p = 0.01) in the group with notches than the group without notches. There were 5 cases of ceramic head fracture. One of them experienced another ceramic liner fracture, assumed to be caused by prosthetic shoulder impingement, after the revision surgical procedure. CONCLUSIONS: The results of this study suggest that impingement between the stem and the ceramic liner occurs in a considerable proportion of patients who underwent total hip arthroplasty not only on the neck but also on the shoulder of the stem. Forceful and abrupt impingement on the stem shoulder can cause ceramic liner fracture. Impingement between the stem shoulder and the ceramic liner should be considered in designing a stem. It seems to be prudent to recommend that patients avoid squatting or sitting cross-legged on the floor as much as possible. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Higher incidence of aseptic loosening caused by a lower canal filling ratio with a modified modular stem in total hip arthroplasty.

PURPOSE: Although a cementless modular prosthesis has shown reliable results, cases of unstable fixation and revision due to aseptic loosening were observed in our institute. The purpose of this study was to clarify the causes of unstable fixation of the prosthesis. METHODS: A total of 144 patients (154 hips) who underwent total hip arthroplasty using the modular prosthesis were retrospectively investigated. For the cohort study, 97 patients (104 hips) were included. The femoral component survival rate and sleeve fixation were assessed at a minimum follow-up of 5 years. Patients were divided into 2 groups, including stable and unstable fixation groups, by sleeve fixation. Clinical and radiographic outcomes were compared. RESULTS: The Kaplan-Meier survival rate at 9 years was 93% with revision for any reason as the endpoint in study cohort. The reasons for revision were recurrent dislocation (1 hip) and aseptic loosening of the stem (5 hips). A total of 88 hips (84.6%) showed stable fixation, and 16 hips (15.4%) showed unstable fixation at final follow-up. There was no significant difference in clinical outcomes between the 2 groups at final follow-up. The canal flare index was significantly higher, and the canal filling ratio was significantly lower in the unstable fixation group. CONCLUSION: Although the modified modular prosthesis was useful for treating anatomically difficult patients, we need to pay attention to both proximal/distal mismatch of the intramedullary canal and the canal filling ratio to achieve stable fixation and good long-term results.

Long-term migration of a cementless stem with different bioactive coatings. Data from a "prime" RSA study: lessons learned.

Background and purpose - Little is known about the long-term migration pattern of cementless stems in total hip arthroplasty (THA). Furthermore, the role of bioactive coatings in fixation, and thus migration, remains uncertain. Hydroxyapatite (HA) is the most commonly used bioactive coating. However, delamination of the coating might induce loosening. Alternatively, fluorapatite (FA) has proved to be more thermostable than HA, thereby potentially increasing longevity. We assessed the long-term migration of cementless stems with different coatings using radiostereometric analysis (RSA), thereby establishing a reference for acceptable migration. Patients and methods - 61 THAs in 53 patients were randomized to receive either a HA, FA, or uncoated Mallory-Head Porous stem during the years 1992 to 1994. Primary outcome was stem migration measured using RSA and secondary outcome was the Harris Hip Score (HHS). Evaluation took place preoperatively and postoperatively on the second day, at 6, 12, 25 and 52 weeks, and annually thereafter. At the 25-year follow-up, 12 patients (17 THAs) had died and 1 patient (1 THA) was lost to follow-up. Due to the high number of missing second-day postoperative RSA radiographs, the 1-year postoperative RSA radiograph was used as baseline for the comparative analyses. Results - Mean follow-up was 17 years (SD 6.6). All stems showed initial rapid migration with median subsidence of 0.2 mm (-0.1 to 0.6) and median retroversion of 0.9° (-3.2 to 2) at 12 months, followed by stable migration reaching a plateau phase. No stem was revised, albeit 1 stem showed continuous subsidence up to 1.5 mm. Comparing the different coatings, we could not find a statistically significant difference in overall 25-year migration (p-values > 0.05). Median subsidence at 15-year follow-up was for HA -0.1 mm (-0.4 to 0.2), for FA 0 mm (-0.1 to 0.2), and for uncoated stems 0.2 mm (-0.1 to 0.5). Median internal rotation at 15-year follow-up was for HA not available, for FA 1.1° (-0.5 to 2.6), and for uncoated stems 0° (-0.5 to 0.4). HHS were also comparable (p-values > 0.05), with at 15-year follow-up for HA 85 points (41-99), for FA 76 points (61-90), and for uncoated stems 79 points (74-90). Interpretation - The long-term migration pattern of cementless stems using different bioactive coatings has not previously been described. No beneficial effect, or side effect at long-term follow-up of bioactive coatings, was found. The provided migration data can be used in future research to establish thresholds for acceptable migration patterns cementless stem designs.

Immediate Breast Reconstruction after mastectomy with polyurethane implants versus textured implants: A retrospective study with focus on capsular contracture.

BACKGROUND: Capsular contracture (CC) is the most common complication following Immediate Breast Reconstruction (IBR) with breast implants. Different implant surfaces were developed aiming to reduce the incidence of CC. We evaluated the incidence and degree of CC after Direct-to-Implant (DTI) IBR with insertion of textured (TE) or polyurethane (PU) covered implants. METHODS: A retrospective review of consecutive patients treated at our Institution with mastectomy and one-stage IBR and implant reconstruction between 2013 and 2018, with or without post mastectomy radiation therapy (PMRT), was conducted. Immediate breast reconstruction was performed by implanting 186 PU covered implants and 172 TE implants. RESULTS: Three-hundred-twelve women underwent 358 DTI IBR with PU or TE implants, were analyzed with a median follow-up time of 2.3 years (range 1.0-3.0). The overall rate of CC Baker grade III and IV was 11.8% (95%CI: 8.4-16.3), while, after PU and TE implant placement it was 8.1% (95% CI: 4.1-15.7) and 15.8% (95% CI: 4.1-15.7) [p = 0.009]), respectively. Irradiated breasts developed CC more frequently rather than non-irradiated breasts (HR = 12.5, p < 0.001), and the relative risk was higher in the TE group compared with the PU group (HR = 0.3, p = 0.003). CONCLUSIONS: After mastectomy and one-stage IBR, the use of PU covered implants is associated with a lower incidence of CC compared to TE implants. This advantage is amplified several folds for patients who necessitate PMRT. Footnote: Capsular contracture (CC); Immediate Breast Reconstruction (IBR); Directto- Implant (DTI); Textured (TE); Polyurethane (PU); Post mastectomy radiation therapy (PMRT); Nipple Sparing mastectomy (NSM).