Migration Of Prosthesis Research Articles

Feasibility of transapical aortic valve implantation fully guided by transesophageal echocardiography

In our case, AR was actually due to the sequelae of endocarditis and not to structural valve degeneration. Technical issues for TAVIin patients with stentlessbioprostheses are different from thoseinpatientswithnativeaorticstenosis or a stented bioprosthesis. Positioning may be more difficult because of the absence of calcification, and the role of concomitant TEE should be emphasized. The absence of calcification or stents may also theoretically increase the risk of prosthesis migration because of potentially less stable anchorage on the aortic annulus. However, this report illustrates the feasibility of TAVI in patients with severe dysfunction of a stentless bioprosthesis. Valve-in-valve implantation may represent a promising opportunity for the future, 5 inasmuch as limited durability is the major concern of stented or stentless bioprostheses. Further studies including a large number of patients and longer follow-up arerequiredtodefinethe exactroleofTAVIin elderly patients with a degenerated bioprosthesis that requires reintervention.

Underestimation of Aortic Flow by Phase Contrast in Aortic Stenosis by Contemporary CMR—Implications for Aortic Valve Area Assessment

report our early experiencewith the transapical procedure at Waikato Hospital. Methods: Between November 2008 and March 2009, 4 patients (3 female) underwent transcatheter transapical aortic valve implantation. The procedure was performed throughasmall anterolateral thoracotomytogainaccess to the left ventricle apex. Valves were deployed under rapid ventricular pacing. 3 patients received 26-mm and 1 23mm Edwards Sapien transcatheter bioprostheses. Results: The mean age was 83.2 years (range 78–89) with amean logistic EuroSCORE of predictedmortality of 20%. Valve implantationwas successful in all patients. The mean gradient decreased from 51± 9 to 15± 3mmHg and the valve area increased from 0.5± to 1.7± 0.2 cm2. There was no prosthesis migration or valve incompetence. One patient developed occlusion of the left main stem treated with stenting but died peri-procedurally due to related vascular complications.Twopatientswereextubated in the cath lab. One patient suffered a small CVA with resolved neurological deficit on follow-up. Paroxysmal atrial fibrillation was noted in 2 patients. No patient required permanent pacemaker implantation. All survivors had marked improvement in functional status. Conclusion:Our initial experience with transapical aortic valve implantation is encouraging. Long-term studies will be required to assess its durability as an alternative to conventional AVR in selected high-risk patients. Method: We have developed an electronic Heart Forecast tool. It provides a graphical story at the time of consultation of current risk (where you are now), how you compare to a peer with ideal risk factor control, what happens to your risk as you get older if you make no changes (the Forecast), and what would happen to your risk in future if you were able to make changes (e.g. stop smoking). The live electronic programwill be available for demonstration. Conclusion: The Heart Forecast captures the shortand long-term probability of an event for each individual integrating both absolute and relative risk concepts. It is simultaneously comprehensive and simple. Early piloting and feedback within primary and secondary care have indicated that this tool significantly supports CVD risk communication and shared decision making. doi:10.1016/j.hlc.2009.04.033

Celecoxib does not appear to affect prosthesis fixation in total knee replacement

Background and purpose After joint replacement, a repair process starts at the interface between bone and cement. If this process is disturbed, the prosthesis may never become rigidly fixed to the bone, leading to migration—and with time, loosening. Cox-2 inhibitors are widely used as postoperative analgesics, and have adverse effects on bone healing. This could tamper prosthesis fixation. We investigated whether celecoxib, a selective Cox-2 inhibitor, increases prosthesis migration in total knee replacement (TKR).Methods 50 patients were randomized to either placebo or celecoxib treatment, 200 mg twice daily, for 3 weeks after TKR (NexGen; Zimmer). Maximum total point motion (MTPM) of the tibial component was measured after 2 years using radiostereometric analysis (RSA). In addition, range of motion, pain, and, subjective outcome were evaluated.Results No differences in prosthesis migration, pain scores, range of motion, and subjective outcome were found after 2 years. Confidence intervals were narrow.Interpretation It is unlikely that Celecoxib increases the risk of loosening, and it may be used safely in conjunction with TKR.

Once-weekly oral medication with alendronate does not prevent migration of knee prostheses

Background and purpose Early migration of joint replacements is an effect of poor fixation and can predict late loosening. By reducing the bone resorption after implantation of a joint replacement, it should be possible to enhance the initial fixation of the implant. We studied the effect of once-weekly treatment with alendronate after knee replacement.Patients and methods We recruited 60 patients (60 knees) with gonarthrosis who were scheduled for a total knee replacement. They were operated on with identical implants and uncemented fixation. 30 patients were treated with a bisphosphonate (alendronate) and 30 patients underwent placebo treatment. The treatment started postoperatively and continued on a weekly basis for 6 months. The fixation of the implants was measured with repeated radiostereometry for 2 years.Results There was no difference in migration of implants between the two groups.Conclusion With uncemented fixation of knee implants, no benefit of once-weekly treatment with alendronate, starting postoperatively, could be seen during a 2-year follow-up period.

Bipolar cemented hip hemiarthroplasty in patients with femoral neck fracture who are on hemodialysis is associated with risk of stem migration

Background and purpose Femoral neck fractures are considerably more common in patients on hemodialysis than in the general population. We determined the outcome of bipolar hemiarthroplasty for hip fracture in patients with long-term hemodialysis and compared it with that of a matched-paired group of patients with intact renal function.Methods We analyzed 26 bipolar hemiarthroplasties in 23 hemodialysed patients with a mean age of 56 (41–78) years who were followed for mean 3.6 (1–8) years. These cases were matched for age, sex, and BMI with 26 patients with femoral neck fractures and normal renal function. The mean follow-up time in the control group was 7 (5–10) years. As primary surgery for their femoral neck fracture, all patients had a bipolar hemiarthroplasty with a 28-mm metal-polyethylene internal articulation and a cemented stem.Results The mortality rate was 21% in the hemodialysed group and 4% in the control group (p = 0.005). The bipolar head migrated in 1 patient in the hemodialysed group but in none of the patients in the case-matched group. In the hemodialysed group, 8 stems migrated and 3 of these were revised, whereas in the control group 3 stems migrated and 2 were revised. The stem migration in the hemodialysed group was not preceded by the development of osteolysis or radiolucent lines at the bone-cement interface. The cumulative survival for prosthesis migration as endpoint was 44% at 5 years in the hemodialysed group and 96% in the control group (p = 0.03).Interpretation The main mode of failure of cemented bipolar hemiarthroplasties in hemodialysed patients is stem migration, due to failure of the bone-cement interface.

Un corps étranger particulier dans le caecum

The authors report a rare complication of total hip replacement - the intrapelvic migration of a hip prosthesis resulting in a cecal fistula.

Intraoperative Ibandronate Reduced Prosthesis Migration After Implantation of Total Knee Prosthesis

Intraoperative Ibandronate Reduced Prosthesis Migration After Implantation of Total Knee Prosthesis

Transapical minimally invasive aortic valve implantation; the initial 50 patients☆

To evaluate the feasibility of minimally invasive transapical beating heart aortic valve implantation (TAP-AVI) for high-risk patients with aortic stenosis. TAP-AVI was performed via a small anterolateral minithoracotomy in 50 patients from February 2006 to March 2007. A balloon expandable transcatheter xenograft (Edwards SAPIEN THV, Edwards Lifesciences, Irvine, CA, USA) was used. Mean age was 82.4+/-5 years and 39 (78%) were female. Implantation was performed in a hybrid operative theatre using fluoroscopic and echocardiographic visualization. Average EuroSCORE predicted risk for mortality was 27.6+/-12%. Seven (14%) patients were re-operations with patent bypass grafts. TAP-AVI (13 patients 23 mm and 37 patients 26 mm) was successfully performed on the beating heart under temporary rapid ventricular pacing in 47 (94%) patients, and implantation was performed completely off-pump in 34 (68%) patients. Three patients required early conversion; two of them were successfully discharged. There was no prosthesis migration or embolization observed. Echocardiography revealed good hemodynamic function in all and minor incompetence in 23 patients, mostly paravalvular, without any signs of hemolysis. Mortality was due to the overall health condition and non-valve related in all patients. Actuarial survival at 1 month, 6 months and 1 year was 92+/-3.8%, 73.9+/-6.2% and 71.4+/-6.5%, respectively. Transapical minimally invasive aortic valve implantation is feasible using an off-pump technique. Good results have been achieved in the initial 50 patients, especially when considering the overall high-risk profile of these patients.

Intrathoracic migration of a breast prosthesis after thoracotomy

Intrathoracic migration of a breast prosthesis after thoracotomy

Esophageal adenocarcinoma developing above an Angelchik prosthesis

The Angelchik device is a horseshoe-shaped prosthesis made of silicone elastomer; it was inserted by the trans-abdominal route to encircle the lower esophagus and was used in the treatment of gastro-esophageal reflux disease. Over 25 000 were inserted worldwide, with acceptable symptom control in between 54% and 95% of patients. However, they were associated with a wide variety of complications, including intractable dysphagia, prosthesis migration and erosion into the stomach, and a significant proportion had to be removed. This article details the cases of three patients in our institution who underwent the insertion of an Angelchik prosthesis and who subsequently developed adenocarcinoma of the esophagus. It is suggested that the Angelchik prosthesis does not effectively prevent acid reflux and thus has no effect in preventing the dysplasia-metaplasia-adenocarcinoma sequence in the lower esophagus.

Clinical Validation of Model-based RSA for a Total Knee Prosthesis

Roentgen stereophotogrammetric analysis generally is accepted as the most accurate method to measure prosthesis migration. A disadvantage of the method is it requires markers in the bone and the prosthesis. Model-based roentgen stereophotogrammetric analysis circumvents the need for markers on prostheses by fitting virtual projections of a three-dimensional surface model of a prosthesis to its actual projections in the roentgen image. We confirmed a model-based roentgen stereophotogrammetric analysis for a tibial component. Using implants with attached markers, we compared model-based roentgen stereophotogrammetric analysis with marker-based roentgen stereophotogrammetric analysis. In addition, we assessed precision of the model-based roentgen stereophotogrammetric analysis with a phantom experiment. The precisions for translations of marker-based and model-based roentgen stereophotogrammetric analysis were 0.06 and 0.11 mm, respectively, and for rotations, the precisions were 0.20 degree and 0.23 degree, respectively. The precisions of model-based roentgen stereophotogrammetric analysis calculated from the phantom data were 0.08 mm for translations and 0.13 degree for rotations. Although model-based roentgen stereophotogrammetric analysis is less precise than marker-based roentgen stereophotogrammetric analysis, its precision is still acceptable for most clinical applications, especially where marker-based roentgen stereophotogrammetric analysis has practical limitations. Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Polytetrafluoroethylene Prosthesis Migration Into the Bladder After Laparoscopic Hernia Repair

Mesh migration after laparoscopic inguinal hernia repair is an unusual and late complication. We report a 50-year-old man with persistent painless hematuria and urinary infection who underwent bilateral laparoscopic intraperitoneal onlay mesh 4 years ago. Polytetrafluoroethylene (PTFE) prosthesis was used and fixed with tackers. The patient underwent cystoscopy and laparotomy for excision of the migrated PTFE prosthesis into the bladder. This is the first case of PTFE prosthesis migration into the bladder after laparoscopic hernia repair. We also reviewed the literature involving migration of mesh after all inguinal hernial repairs.

The Constrained Acetabular Component for Hip Instability

One hundred four hips in 107 patients undergoing revision arthroplasty of the hip were identified at risk of dislocation and treated with the constrained cup. Radiostereometric analysis was performed to assess prosthesis migration. Mean follow-up was 3.0 years (range, 2.0-4.8). At last review, 19 patients had died and 6 were lost to follow-up. There were 5 revisions for cup loosening and a further 4 with radiographic evidence of loosening. There were 3 dislocations and 3 dissociations in 5 patients. Radiostereometric analysis demonstrated that cup migration at 24 months was up to 0.82 mm of translation and 1.58° of rotation. Our results confirm that the constrained acetabular component is a highly effective option for the treatment for patients with instability of the hip. The aseptic loosening rate was higher than previously reported.

A Hydroxyapatite Graft Substitute Reduces Subsidence in a Femoral Impaction Grafting Model

Synthetic bone graft substitutes have been developed for impaction grafting revision hip surgery in response to concerns about the availability and potential infection risk of allograft. We performed an in vitro experiment to determine whether a synthetic porous hydroxyapatite material might improve resistance to cumulative subsidence and cyclic (elastic) movement on loading. We impacted different ratios of hydroxyapatite and allograft (0%, 50%, 70%, and 90% hydroxyapatite) into composite femoral models (eight per group) and implanted tapered, polished stems with cement. Models were loaded for 18,000 cycles on a servohydraulic materials testing machine. Migration of the femoral prostheses and the distal cement was determined using radiostereometric analysis, and cyclic movement was measured mechanically by the testing machine. Hydroxyapatite decreased overall subsidence and subsidence at the prosthesis-cement interface, but there was no difference at the cement-femur interface. This decrease may have occurred because the hydroxyapatite-containing graft was more rigid, or because it resulted in a thicker cement mantle. Cyclic prosthesis movement also was lower with hydroxyapatite. While the biologic response to porous hydroxyapatite remains to be determined, its mechanical properties appear promising.

Local peroperative treatment with a bisphosphonate improves the fixation of total knee prostheses: A randomized, double-blind radiostereometric study of 50 patients

Background Postoperative migration of a joint prosthesis is related to the risk of late loosening. We have previously reported that oral treatment with clodronate reduced migration of the cemented NexGen total knee prosthesis during the first postoperative year, as measured by radiostereometry (RSA). Oral bisphosphonate treatment is sometimes unpleasant, and local treatment will enable higher local concentrations. We now report the results of local peroperative treatment with another bisphosphonate, ibandronate, with the same prosthesis.Methods This is a double-blind, randomized study of 50 patients using RSA with maximal total point motion (MTPM) as primary effect variable. 1 mg ibandronate (1 mL) or 1 mL saline was applied to the tibial bone surface 1 min before cementation. RSA examination was done on the first postoperative day, and at 6, 12, and 24 months.Results One ibandronate-treated patient died of unrelated causes, and 1 control patient refused to come for follow-up, leaving 24 patients in each group for analysis. There were no cases of aseptic loosening. By repeated measures ANOVA, migration (MTPM) was reduced by local application of ibandronate (p = 0.006). The effect was most pronounced at 6 months, with a reduction from 0.45 to 0.32 mm (95% CI for reduction: 0.04–0.21 mm). At 12 months, the migration from the postoperative examination was reduced from 0.47 to 0.36 mm (95% CI for reduction: 0.02–0.20 mm). At 24 months, the reduction was from 0.47 to 0.40 mm (95% CI: -0.01–0.16 mm).Interpretation This is the first study to show improvement of prosthesis fixation by local pharmacological treatment in humans. The treatment appears to be safe, cheap, and easy to perform. However, the improvement in postoperative stability was not greater than with systemic clodronate treatment.

The suturing concept for laparoscopic mesh fixation in ventral and incisional hernia repair: Mid-term analysis of 400 cases

The authors describe a minimally invasive treatment of moderate to large incisional and ventral hernia defects using Parietex composite mesh. All defects are closed laparoscopically or through a minilaparotomy using sutures, and the composite mesh is fixed intraperitonally using transabdominal fixation with nonabsorbable sutures to avoid the use of staple or tack fixation, which has been associated with various complications, including major loop adhesion and mesh migration. The midterm results for 400 patients are presented in terms of efficacy and safety. During a mean follow-up period of 28 months for 80% of the patients, the median operating time was 74 min and the median hospital stay was 3 days. There were eight seromas (2%), all on large defects. Transient pain was experienced by 10 patients (2.5%), and resolved over time with analgesic treatment. There was one early case of sepsis (0.25%), attributable to secondary breakdown of the bowel wall in a case of recurrent incisional hernia, which led to removal of the mesh. Residual chronic parietal pain was reported for 10 patients (2.5%), 2 of whom were released after excision of neuroma; 3 trocar-site herniations (0.75%); and lipoma formation on the site of the hernia sac in 6 cases (1.5%). Laparoscopic ventral hernia treatment using Parietex composite mesh is an effective and safe procedure. Morbidity and recurrence rates are low, and the 2-year outcomes are promising, with no prosthesis migration or complication related to intraperitoneal positioning of the mesh.

Periapatite May Not Improve Micromotion of Knee Prostheses in Rheumatoid Arthritis

Prosthesis migration in bone inevitably occurs in cemented and uncemented total knee arthroplasty tibial components. Cemented designs as the gold standard give immediate fixation whereas cementless designs need a period of bone ingrowth onto the surface irregularities of the implants. The addition of bioactive coatings may enhance this process of ingrowth. A controlled randomized prospective RSA study was carried out on 26 Duracon implants in a rheumatoid arthritis patient group to evaluate the effect of a periapatite coating on the fixation of the tibial tray. The coated and the noncoated groups were matched for sex, age, body mass index, and HSS Knee Score. Stage of preoperative joint destruction and preoperative and postoperative mechanical leg axis showed no differences. We saw no differences in migration between the two groups, but a trend for lesser translations along and rotations about all three axes in the periapatite group. The periapatite-coated components showed a lower variance in subsidence than did the uncoated components. Both groups also showed a high variance in anterior tilting of the components. The cementless PA-coated Duracon prosthesis used in patients with RA may provide improved fixation of tibial components although we could not demonstrate improvement in this small controlled series. Therapeutic Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Migration and cyclic motion of a new short-stemmed hip prosthesis – a biomechanical in vitro study

Uncemented, short-stemmed hip prostheses have been developed to reduce the risk of stress shielding and to preserve femural bone stock. The long-term success of these implants is yet uncertain. Prerequisite for osseointegration is sufficient primary stability. In this study the cyclic motion and migration patterns of a new short-stemmed hip implant were compared with those for two clinically successful shaft prostheses. The prostheses were implanted in paired fresh human femura and loaded dynamically (gait cycle) with increasing load (max 2,100 N) up to 15,000 cycles. Relative displacements between prosthesis and bone were recorded using a 3D-video analysis system. The short stem displayed a biphasic migration pattern with stabilisation at maximum load. Initial migration was predominantly into varus and was greater than that for the shaft prostheses. Failure occurred in cases of poor bone quality and malpositioning. Cyclic motion of the short prosthesis was less than that for the shaft prostheses. Surface finish showed no effect. System stiffness for the new stem was lower than for the shaft prostheses. The new stem tended to migrate initially more than the shaft prostheses, but stabilised when cortical contact was achieved or the cancellous bone was compacted sufficiently. Bone quality and correct positioning were important factors for the short stem. The lower cyclic motion of the new stem should be favourable for bony ingrowth. The lower system bending stiffness with the new implant indicated a more physiological loading of the bone and should thereby reduce the effects of stress shielding.

Computed Tomography Assessment of the Accuracy of In Vivo Placement of Artificial Discs in the Lumbar Spine Including Radiographic and Clinical Consequences

Prospective cohort study of 52 patients who had undergone artificial lumbar disc replacement. To evaluate the implantation accuracy of prosthesis positioning, subsequent facet joint changes and prosthesis migration, and the clinical consequences of implant position. Accuracy of spinal prosthesis implantation has not been evaluated rigorously, especially with a mini-incision approach. It is unknown if the inexact placement of a mobile device in the spine has any biomechanical, radiographic, or clinical repercussions. A total of 52 consecutive patients were treated using standard methods of disc implantation with an intervertebral prosthesis. Computed tomography scans were performed within 3 days and again at 6 to 24 months. An independent radiologist analyzed the images for prosthesis position, rotation, migration, and facet changes. Results were compared with clinical outcome, measured by the Visual Analog Scale and Oswestry Disability Index. Deviation of the prosthesis from the center position was under 1.2 mm, and rotation off of midline was under 12 degrees. Follow-up CT scans showed no migration or facet changes. Regression analysis showed no correlation of prosthesis position with clinical outcome. Current prosthetic disc implantation methods, with minimally invasive access techniques, are relatively accurate. Although there can be deviation of the prosthesis from ideal placement, no repercussions were attributable.

Postoperative clodronate decreases prosthetic migration: 4–year follow-up of a randomized radiostereometric study of 50 total knee patients

Background We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year, as measured by radiostereometry (RSA). We now report the 4-year results.Methods This was a double-blind randomized study, using RSA with maximal total point motion (MTPM).Results With analysis according to the “intention to treat” principle, the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis (a secondary variable) in the clodronate group. However, 3 patients (all clodronate) did not take any tablet after surgery. If they are excluded, there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline, with the clodronate group showing 25% less migration. From 1 to 4 years, there was no difference in migration rate by MTPM, but there was a continuous increase in rotation around the transverse axis in the controls, which differed from the clodronate group. There were no cases of aseptic loosening. 2 patients had migration of more than 1.3 mm from baseline to 4 years; neither of them had taken clodronate. The others had migration of less than 0.9 mm.Interpretation Because migration was clearly reduced by clodronate during the first postoperative year, and there was still a difference at 4 years when analyzed per protocol, it appears likely that this treatment can diminish the risk of loosening. The difference in the number of outliers also points in this direction, and may be more relevant than mean migration values.