High Rate Of Mechanical Failure Research Articles

(114) A Comparative Meta-Analysis of Revision Strategies for Malfunctioning Inflatable Penile Prosthesis: Partial vs Complete Component Replacement With or Without Retained Reservoir

Abstract Introduction In cases of non-infected malfunctioning Inflatable penile prosthesis (IPP) device, surgeon often opt to exchange all the device rather than the defective component for fear of increased infection rate and future mechanical dysfunction. Objective To assess whether partial component exchange of IPP device has comparable outcomes to complete explant and replacement of IPP device with or without retained reservoir. Methods A meta-analysis was completed in line with PRISMA 2020 and AMSTAR guidelines. A comprehensive search was done on MEDLINE (OVID), PubMed, and Cochrane Library electronic databases from their inceptions until May 2023, identifying studies that reported on outcomes and complications of revision surgery for non-infected malfunctioning IPP device. Three groups were compared: the first group underwent a single or two-component exchange, the second group had a complete explant replacement of the entire device, and the third group had replacement of all components with a drained and retained primary reservoir. Results A total of 9 articles were included in the analysis. 12,152 patients had complete replacement of their device, 128 had partial exchange of their device and 151 patients had “drained and retained” reservoir following revision. The mean age was similar among the 3 groups between 62–68 years. The median follows up time ranged between 12 and 79 months. Partial component ex change had a higher rate of mechanical failure 10.3% versus 1.3% and 2.3 % (p=0.03) for complete and “drain and retain” groups respectively. (Figure 1) Similarly, partial component exchange had higher peri-operative complications at 21.2% compared to complete replacement group 9.5% and “drain and retain” group 14.5% (p=0.022). However, the infection rate was similar among the three groups, 7.7%, 2.7% and 3.3% respectively (p= 0.301). (Figure 2) Conclusions Partial component exchange during IPP revision has higher rates of perioperative complication and future mechanical failure but has similar rate of infection compared to complete component replacement with or without “drain and retain” of original reservoir. Disclosure No.

Biomechanical effects of a novel posteriorly placed sacroiliac joint fusion device integrated with traditional lumbopelvic long-construct instrumentation.

S2-alar-iliac (S2AI) screw fixation effectively ensures stability and enhances fusion in long-segment constructs. Nevertheless, pelvic fixation is associated with a high rate of mechanical failure. Because of the transarticular nature of the S2AI screw, adding a second point of fixation may provide additional stability and attenuate strains. The objective of the study was to evaluate changes in stability and strain with the integration of a sacroiliac (SI) joint fusion device, implanted through a novel posterior SI approach, supplemental to posterior long-segment fusion. L1-pelvis human cadaveric specimens underwent pure moment (7.5 Nm) and compression (400 N) tests in the following conditions: 1) intact, 2) L2-S1 pedicle screw and rod fixation with L5-S1 interbody fusion, 3) added S2AI screws, and 4) added bilateral SI joint fixation (SIJF). The range of motion (ROM), rod strain, and screw bending moments (S1 and S2AI) were analyzed. S2AI fixation decreased L2-S1 ROM in flexion-extension (p ≤ 0.04), L5-S1 ROM in flexion-extension and compression (p ≤ 0.004), and SI joint ROM during flexion-extension and lateral bending (p ≤ 0.03) compared with S1 fixation. SI joint ROM was significantly less with SIJF in place than with the intact joint, S1, and S2AI fixation in flexion-extension and lateral bending (p ≤ 0.01). The S1 screw bending moment decreased following S2AI fixation by as much as 78% in extension, but with statistical significance only in right axial rotation (p = 0.03). Extending fixation to S2AI significantly increased the rod strain at L5-S1 during flexion, axial rotation, and compression (p ≤ 0.048). SIJF was associated with a slight increase in rod strain versus S2AI fixation alone at L5-S1 during left lateral bending (p = 0.048). Compared with the S1 condition, fixation to S2AI increased the mean rod strain at L5-S1 during compression (p = 0.048). The rod strain at L5-S1 was not statistically different with SIJF compared with S2AI fixation (p ≥ 0.12). Constructs ending with an S2AI screw versus an S1 screw tended to be more stable, with reduced SI joint motion. S2AI fixation decreased the S1 screw bending moments compared with fixation ending at S1. These benefits were paired with increased rod strain at L5-S1. Supplementation of S2AI fixation with SIJF implants provided further reductions (approximately 30%) in the sagittal plane and lateral bending SI joint motion compared with fixation ending at the S2AI position. This stability was not paired with significant changes in rod or screw strains.

Long-term follow-up of children treated with the Repiphysis expandable prosthesis for lower extremity bone sarcoma.

Expandable endoprostheses provide a limb salvage option for skeletally immature patients with bone sarcoma of the lower extremities. Initial reports of the Repiphysis prosthesis were encouraging; however, medium-term follow-up revealed high complication rates. We report on the long-term follow-up of a cohort of patients treated with the Repiphysis prosthesis. Eleven patients were included in the study. Data collected included sex, age at surgery, duration of follow-up, site of disease, histologic diagnosis, number of lengthening sessions, amount lengthened, postoperative complications, endoprosthetic failure, mode of endoprosthetic failure, duration from index surgery to failure and to revision, type of revision surgery and final limb-length discrepancy. The average duration of follow-up from the time of surgery was 180 months (range, 144-215 months). Fifteen Repiphysis implants were used in 11 patients. All implants failed with an average time from surgery to failure of 36 months (range, 3-72 months). Twenty-four complications were observed: one wound dehiscence, two deep infections, 18 mechanical failures, implant collapse with destruction of proximal tibia epiphysis in two and one periprosthetic proximal femur fracture with dislodgement of the stem. Despite being an option for limb salvage, the Repiphysis prosthesis has a high rate of mechanical failure and need for revision, similar to other expandable implants. The authors, therefore, recommend full disclosure of the potential short- and long-term complications and need for revision, as well as alternative treatment options if their use is considered. Level of evidence: IV (Therapeutic).

Long-term follow-up of all-polyethylene tibial components when used for oncological endoprosthetic reconstruction.

We aimed to examine the long-term mechanical survivorship, describe the modes of all-cause failure, and identify risk factors for mechanical failure of all-polyethylene tibial components in endoprosthetic reconstruction. This is a retrospective database review of consecutive endoprosthetic reconstructions performed for oncological indications between 1980 and 2019. Patients with all-polyethylene tibial components were isolated and analyzed for revision for mechanical failure. Outcomes included survival of the all-polyethylene tibial component, revision surgery categorized according to the Henderson Failure Mode Classification, and complications and functional outcome, as assessed by the Musculoskeletal Tumor Society (MSTS) score at the final follow-up. A total of 278 patients were identified with 289 all-polyethylene tibial components. Mechanical survival was 98.4%, 91.1%, and 85.2% at five, ten and 15 years, respectively. A total of 15 mechanical failures were identified at the final follow-up. Of the 13 all-polyethylene tibial components used for revision of a previous tibial component, five (38.5%) failed mechanically. Younger patients (< 18 years vs > 18 years; p = 0.005) and those used as revision components (p < 0.001) had significantly increased rates of failure. Multivariate logistic regression modelling showed revision status to be a positive risk factor for failure (odds ratio (OR) 19.498, 95% confidence interval (CI) 4.598 to 82.676) and increasing age was a negative risk factor for failure (OR 0.927, 95% CI 0.872 to 0.987). Age-stratified risk analysis showed that age > 24 years was no longer a statistically significant risk factor for failure. The final mean MSTS score for all patients was 89% (8.5% to 100.0%). The long-term mechanical survivorship of all-polyethylene tibial components when used for tumour endoprostheses was excellent. Tumour surgeons should consider using these components for their durability and the secondary benefits of reduced cost and ease of removal and revision. However, caution should be taken when using all-polyethylene tibial components in the revision setting as a significantly higher rate of mechanical failure was seen in this group of patients. Cite this article: Bone Joint J. 2020;102-B(2):170-176.

Constrained Liner Revision Is Less Effective With Each Subsequent Constrained Liner Revision at Preventing Instability

BackgroundConstrained liners are used to treat recurring total hip arthroplasty dislocations in certain patients. Little is known about the fate of constrained liner revisions. The aim of this study is to evaluate the rate and survivorship free of revision for mechanical failure of constrained liners in patients who were revised to their first, second, and third constrained liners. MethodsFrom 1989 to 2016, using our institution’s total joint registry, we identified 554 revisions to a first constrained liner. Of the 554, 40 had mechanical failure of their index constrained liner and had revision to a second constrained liner. Of the 40, 13 had mechanical failure of their second constrained liner and had revision to a third constrained liner. Patients included in the failure analysis had minimum 2-year follow-up, with a mean follow-up of 5.5 years. ResultsIn patients receiving their first, second, and third constrained liners, the survivorship free of revision for mechanical failure at 4 years was 90%, 52%, and 28%, respectively. Patients with a second and third constrained liner were more likely to have a revision for mechanical failure (second odds ratio 8, P < .0001; third odds ratio 10, P < .0001) compared to those receiving their first constrained liner. Using a different constrained liner did not decrease the risk of failure. ConclusionAfter revision to a second or third constrained liner there is high rate of mechanical failure. When a total hip arthroplasty becomes unstable after constrained liner, surgeons should exercise caution before revising to another constrained liner.

Revision Techniques After Artificial Urinary Sphincter Failure in Men: Results From a Multicenter Study

To compare the results of various single-component artificial urinary sphincter (AUS) revision techniques for continued/recurrent stress urinary incontinence (SUI). Although AUS placement for male SUI has a high rate of success, revisions may be performed for mechanical failure of an isolated component or continued/recurrent SUI. From 1993 to 2012, 90 AUS revisions including urethral cuff downsizing (19), pressure-regulating balloon replacement (18), cuff repositioning (11), or tandem cuff placement (42) were performed at 2 institutions. End points included reoperation, incontinence failure, and urethral erosion. The Kruskal-Wallis test was used to compare continuous variables, and the log-rank test was used to compare Kaplan-Meier curves. Mean age was 70.2 years, and median follow-up was 33.6 months. Median time to revision was 28.9 months. Tandem cuff placement was associated with a lower rate of incontinence failure (P = .02), whereas cuff repositioning was associated with a higher rate of incontinence failure (P = .02). An increased rate of mechanical failure was observed with cuff downsizing (P = .01). Among options for revision (1) cuff downsizing is associated with a higher rate of mechanical failure, and (2) cuff repositioning with the same size is associated with a higher rate of incontinence failure, whereas (3) tandem cuff placement is associated with a lower rate of recurrent SUI compared to other types of AUS revision. Cuff repositioning is associated with an increased rate of persistent incontinence after AUS revision whereas tandem cuff placement is associated with a lower rate of recurrent or persistent incontinence.

Sacropelvic fixation in adult spinal deformity (ASD); a very high rate of mechanical failure.

Sacropelvic fixation (SPF) is an integral part of ASD surgery. Literature suggests that combination of S1 and iliac screws may be associated with lowest rate of complications. To analyze the rate and potential factors of mechanical failure associated with SPF in adult spinal deformity surgery. Of 504 patients enrolled in a prospective multicentric database, 239 were treated conservatively and 265 were treated surgically. Forty-five of those who had sacroiliac fixations and with >6 months (or to failure) f/up constitute the population. Type of iliac fixation was S2 alar/iliac (S2AI) screws in 20 (44.4%) and iliac screws with lateral connectors (IwL) in 25 (55.6%). Diagnoses were degenerative in 20, failed back in 11 and other in 14. Average instrumentation length was 11.6 ± 4.0 levels. Cases with failure were compared to those without using Fisher's Exact and Mann-Whitney U tests. A total of 16 implant related complications were identified (35.6%). Failures were identified on an average of 224.1 days (8-709) following index surgery. Failure rate of S2AI screws was 35 vs. 12% for IwL screws (p > 0.05). All broken screws were associated with S2AI technique with polyaxial screws. Comparison of failed cases to others revealed that failed cases had inadequate restoration of Lumbar Lordosis but this was not statistically insignificant. Only age was a significantly different, patient with failure being older. Pelvic fixation is still associated with a very high rate of mechanical failure. Major risk factors appear to be age and type of fixation. Although could not be shown to be statistically significant, failure to restore the optimal sagittal balance may be a contributing factor as well. So in conclusion, in cases with suboptimal sagittal plane correction, S2AI with polyaxial screws seem to have higher risk of short-term acute failure compared to IwL.

MP38-11 LONG-TERM FOLLOWUP COMPARISON OF VARIOUS ARTIFICIAL URINARY SPHINCTER REVISION METHODS

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Incontinence Therapy II1 Apr 2014MP38-11 LONG-TERM FOLLOWUP COMPARISON OF VARIOUS ARTIFICIAL URINARY SPHINCTER REVISION METHODS Jairam Eswara, Robert Chan, Joel Vetter, Henry Lai, Timothy Boone, and Steven Brandes Jairam EswaraJairam Eswara More articles by this author , Robert ChanRobert Chan More articles by this author , Joel VetterJoel Vetter More articles by this author , Henry LaiHenry Lai More articles by this author , Timothy BooneTimothy Boone More articles by this author , and Steven BrandesSteven Brandes More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1268AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The purpose of this study is to compare the long-term results of patients who underwent artificial urinary sphincter (AUS) revision for recurrent or continued urinary incontinence. METHODS From 1988-2012, 89 AUS revisions were performed at 2 institutions. AUS revision including urethral cuff downsizing, replacement of the pressure-regulating balloon (PRB), cuff repositioning, or tandem cuff placement was performed for recurrent or persistent SUI. Of the 89 original surgeries, cuff sizes were 3.5cm (2), 4.0 (76), 4.5 (11), and all used a 61-70cm H2O PRB. The endpoints were reoperation or worsening stress urinary incontinence (the use of pads) as described by the patient. Student’s t-test was used to compare continuous normally distributed variables, and Kaplan-Meier curves were compared using the log rank test. RESULTS Revision methods to correct continued SUI included the following: urethral cuff downsizing to 3.5cm (14) and to 4.0cm (4), replacement of the 61-70cm H2O PRB to 71-80cm H20 (19), cuff repositioning (10), and tandem cuff placement (42). Mean age was 67.9 years and median follow-up was 35.2 months. Median time to revision was 33.2 months. Patients who underwent cuff downsizing for continued incontinence had a higher rate of mechanical failure compared to all other forms of AUS revision (p=0.016). No increased rate of urethral erosion was observed between the two groups (p=0.244). There was no significant difference among the AUS revision groups with regard to incontinence failure (p=0.313), mechanical failure (p=0.310), urethral erosion (p=0.448), or overall failure (p=0.336). When assessed individually, none of the revisions was associated with a higher rate of incontinence failure compared to the rest of the cohort: cuff downsizing (p=0.137), PRB replacement (p=0.737), cuff repositioning (p=0.354), and tandem cuff placement (p=0.146). CONCLUSIONS AUS cuff downsizing for recurrent or persistent SUI is associated with a higher rate of mechanical failure and thus is a less desirable salvage method if alternatives are possible. In the properly selected patient all other revision methods, including PRB replacement, cuff repositioning, or tandem cuff placement are equally safe, effective, and durable. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e404-e405 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Jairam Eswara More articles by this author Robert Chan More articles by this author Joel Vetter More articles by this author Henry Lai More articles by this author Timothy Boone More articles by this author Steven Brandes More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Mechanical Failure After Locking Plate Fixation of Unstable Intertrochanteric Femur Fractures

The aim of this study was analyze modes of mechanical failure in a consecutive cohort of patients and establish possible risk factors. This was a retrospective cohort study. The study was conducted at an academic level-1 trauma center. Twenty-nine patients (mean age 56 years, range 21-92; 45% males, 41% smokers, 17% diabetic, mean body mass index 26.9, range 20-56) with 30 OTA 31A3 fractures treated between 2003 and 2007 were included. Operative fixation using 4.5-mm locking compression plate (LCP) proximal femur plate (Synthes, Paoli, PA). Mechanical failure was defined as loss of alignment of at least 10° or shortening of at least 2 cm. Secondary outcomes included patient and fixation construct variables as possible predictors for mechanical failure. At 20 months of follow-up, 11 failures (37%) occurred. Mean time to failure was 18 weeks (range 2-84). Cumulative failure rates were 10%, 20%, 27%, and 33% at 1, 2, 6, and 12 months, respectively. The most frequent failure mode was varus collapse with screw cut out (5 cases). There was no statistically significant difference between groups with regards to age, body mass index, diabetes, or smoking habit. The presence of a "kickstand screw" and medial cortical reduction were not significantly different in cases with and without failure. Proximal screw number and type were similar in both groups. A high rate of mechanical failure can be expected with proximal locking plate fixation of unstable proximal femur fractures. The use of a "kickstand" screw could not be established to reduce the risk for mechanical failure. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Effects of low intensity pulsed ultrasound with and without increased cortical porosity on structural bone allograft incorporation

BackgroundThough used for over a century, structural bone allografts suffer from a high rate of mechanical failure due to limited graft revitalization even after extended periods in vivo. Novel strategies that aim to improve graft incorporation are lacking but necessary to improve the long-term clinical outcome of patients receiving bone allografts. The current study evaluated the effect of low-intensity pulsed ultrasound (LIPUS), a potent exogenous biophysical stimulus used clinically to accelerate the course of fresh fracture healing, and longitudinal allograft perforations (LAP) as non-invasive therapies to improve revitalization of intercalary allografts in a sheep model.MethodsFifteen skeletally-mature ewes were assigned to five experimental groups based on allograft type and treatment: +CTL, -CTL, LIPUS, LAP, LIPUS+LAP. The +CTL animals (n = 3) received a tibial ostectomy with immediate replacement of the resected autologous graft. The -CTL group (n = 3) received fresh frozen ovine tibial allografts. The +CTL and -CTL groups did not receive LAP or LIPUS treatments. The LIPUS treatment group (n = 3), following grafting with fresh frozen ovine tibial allografts, received ultrasound stimulation for 20 minutes/day, 5 days/week, for the duration of the healing period. The LAP treatment group (n = 3) received fresh frozen ovine allografts with 500 μm longitudinal perforations that extended 10 mm into the graft. The LIPUS+LAP treatment group (n = 3) received both LIPUS and LAP interventions. All animals were humanely euthanized four months following graft transplantation for biomechanical and histological analysis.ResultsAfter four months of healing, daily LIPUS stimulation of the host-allograft junctions, alone or in combination with LAP, resulted in 30% increases in reconstruction stiffness, paralleled by significant increases (p < 0.001) in callus maturity and periosteal bridging across the host/allograft interfaces. Longitudinal perforations extending 10 mm into the proximal and distal endplates filled to varying degrees with new appositional bone and significantly accelerated revitalization of the allografts compared to controls.ConclusionThe current study has demonstrated in a large animal model the potential of both LIPUS and LAP therapy to improve the degree of allograft incorporation. LAP may provide an option for increasing porosity, and thus potential in vivo osseous apposition and revitalization, without adversely affecting the structural integrity of the graft.

A mechanical and computational investigation on the effects of conduit orientation on the strength of massive bone allografts

Structural bone allografts are used to reconstruct large skeletal defects resulting from trauma, tumor resection, or revision arthroplasty. Though used for over a century, bone allografts suffer from a high rate of mechanical failure due to limited graft revitalization even after extended periods in vivo. The current study evaluated the mechanical properties of longitudinally perforated cortical bone allografts (LAP) that have been shown to promote accelerated graft incorporation in a large animal model. The compressive and tensile properties of longitudinally perforated allograft specimens, as determined through uniaxial compression and diametral compression tests, respectively, were not significantly affected by the presence of the conduit. However, transversely perforated grafts (TAP) demonstrated a marked decrease in tensile capacity ( p = 0.04). Finite element analysis demonstrated moderate increases in the maximum principal stresses in LAP specimens while TAP models indicated an 83.4% increase in maximum principle stress near the conduit on the endosteal surface of the graft. This research and the previous in vivo study suggest that LAP adequately serves as an internal template within the cortical bone allograft for osseous apposition and revitalization without adversely affecting the structural or mechanical integrity of the graft.

Total hip arthroplasty for osteonecrosis: Matched-pair analysis of 188 hips with long-term follow-up

A matched comparison was made between total hip arthroplasties done for osteonecrosis and those done for osteoarthritis. Patients were matched for age, sex, surgical approach, prosthesis, and surgeon. All received cemented Charnley replacements and had minimal follow-up of 10 years. There were 118 women and 70 men with a mean age of 58 years. Thirty-five patients were younger than 50. The mean follow-up was 17.8 years (range, 10 to 25.4 years). Revision rates for osteonecrosis and osteoarthritis were 18% and 19% (not significant). The mechanical failure rate (revision for loosening plus radiographic loosening) was greater, but not significantly so, in the osteonecrosis group. In patients younger than 50 years, the revision rate in osteonecrosis (50%) was significantly higher than that in any other group. Similarly, the mechanical failure rate in osteonecrosis was significantly greater in the patients younger than 50. Radiographic femoral loosening was greater in osteonecrosis at all follow-up intervals, and dislocations occurred more frequently in the osteonecrosis group than in the osteoarthritis group. Results of arthroplasty in both groups were comparable in patients over 50 years of age, although patients with osteonecrosis had an increased rate of dislocation. Patients with osteonecrosis who are younger than 50 years have a significantly higher rate of mechanical failure than those with osteoarthritis who are younger than 50 years. Cemented total hip arthroplasty should be recommended in this group with caution if at all.