Marc J. Nieuwenhuijse

Cement leakage in percutaneous vertebroplasty for osteoporotic vertebral compression fractures: identification of risk factors

BACKGROUND CONTEXT Percutaneous vertebroplasty (PVP) is a common treatment modality for painful osteoporotic vertebral compression fractures (OVCFs). The complication rate of PVP is low, but cement leakage occurs in up to 90% of the treated levels. Recent evidence suggests that sequelae of cement leakage may be more common and clinically relevant than previously thought. Preoperative appreciation of risk factors would therefore be helpful but has not been thoroughly investigated. PURPOSE Identification of preoperative risk factors for the occurrence of cement leakage in PVP for painful OVCFs. STUDY DESIGN Retrospective assessment of risk factors using multivariate analysis. PATIENT SAMPLE Eighty-nine patients treated with PVP for 177 painful OVCFs. OUTCOME MEASURE Occurrence of cement leakage. METHODS The influence of all known risk factors and other parameters potentially affecting the occurrence of cement leakage was retrospectively assessed using multivariate analysis. Patient age, sex, and spinal deformity index; fracture age, level, type, and semiquantitative severity grade (1-4), the presence of an intravertebral cleft and/or cortical disruption on preoperative magnetic resonance imaging (MRI), and the viscosity of bone cement were included. Cement leakage was assessed on direct postoperative computed tomography scanning of the treated levels. In addition to cement leakage in general, three fundamentally different leakage types (cortical, epidural, and anterior venous), with different possible clinical sequelae, were discerned, and their respective risk factors were assessed. RESULTS In 130 of 173 (75.1%) treated OVCFs, cement leakage was detected. Leakage incidence was found to increase approximately linear with advancing severity grade. High fracture semiquantitative severity grade (adjusted per grade relative risk [RR], 1.14; 95% confidence interval [CI], 1.05-1.24; p=.002) and low bone cement viscosity (medium vs. low viscosity: adjusted RR, 0.73; 95% CI, 0.61-0.87; p<.001) were strong risk factors for cement leakage in general. For cortical leakage (in 95% intradiscal leakage), the presence of cortical disruption on MRI (adjusted RR, 1.62; 95% CI, 1.16-2.26; p=.004) and an intravertebral cleft on MRI (adjusted RR, 1.43; 95% CI, 1.07-1.77; p=.017) were identified as additional strong risk factors. CONCLUSIONS High fracture severity grade and low viscosity of polymethylmethacrylate bone cement are general, strong, and independent risk factors for cement leakage. Using MRI assessment, cortical disruption and the presence of an intravertrebral cleft were identified as additional strong risk factors regarding cortical (intradiscal) cement leakage, thereby potentiating anticipation.

RSA and Registries: The Quest for Phased Introduction of New Implants

INTRODUCTION Although the overall survival of knee and hip prostheses at ten years averages 90%, recent problems with several hip and knee prostheses have illustrated that the orthopaedic community, industry, and regulators can still further improve patient safety. Given the early predictive properties of roentgen stereophotogrammetric analysis (RSA) and the meticulous follow-up of national joint registries, these two methods are ideal tools for such a phased clinical introduction. In this paper, we elaborate on the predictive power of RSA within a two-year follow-up after arthroplasty and its relationship to national joint registries. The association between RSA prosthesis-migration data and registry data is evaluated. METHODS The five-year rate of revision of RSA-tested total knee replacements was compared with that of non-RSA-tested total knee replacements. Data were extracted from the published results of the national joint registries of Sweden, Australia, and New Zealand. RESULTS There was a 22% to 35% reduction in the number of revisions of RSA-tested total knee replacements as compared with non-RSA-tested total knee replacements in the national joint registries. Assuming that the total cost of total knee arthroplasty is

Early proximal migration of cups is associated with late revision in THA: A systematic review and meta-analysis of 26 RSA studies and 49 survival studies

37,000 in the United States, a 22% to 35% reduction in the number of revisions (currently close to 55,000 annually) could lead to an estimated annual savings of over

Percutaneous vertebroplasty for the treatment of osteoporotic vertebral compression fractures: EVALUATION AFTER 36 MONTHS

400 million to the health-care system. CONCLUSION The phased clinical introduction of new prostheses with two-year RSA results as a qualitative tool could lead to better patient care and could reduce the costs associated with revision total knee arthroplasty. Follow-up in registries is necessary to substantiate these results and to improve post-market surveillance.

Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies

This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited.Background and purpose The association between excessive early migration of acetabular cups and late aseptic revision has been scantily reported. We therefore performed 2 parallel systematic reviews and meta-analyses to determine the association between early migration of acetabular cups and late aseptic revision. Methods One review covered early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were classified according the Swedish Hip Arthroplasty Register and the Australian National Joint Replacement Registry: < 5% revision at 10 years. Results Following an elaborate literature search, 26 studies (involving 700 cups) were included in the RSA review and 49 studies (involving 38,013 cups) were included in the survival review. For every mm increase in 2-year proximal migration, there was a 10% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, proximal migration of up to 0.2 mm was considered acceptable and proximal migration of 1.0 mm or more was considered unacceptable. Cups with proximal migration of between 0.2 and 1.0 mm were considered to be at risk of having revision rates higher than 5% at 10 years. Interpretation There was a clinically relevant association between early migration of acetabular cups and late revision due to loosening. The proposed migration thresholds can be implemented in a phased evidence-based introduction, since they allow early detection of high-risk cups while exposing a small number of patients.

Good diagnostic performance of early migration as a predictor of late aseptic loosening of acetabular cups: results from ten years of follow-up with Roentgen stereophotogrammetric analysis (RSA).

In a prospective study between August 2002 and August 2005, we studied the quantitative clinical and radiological outcome 36 months after percutaneous vertebroplasty for intractable type-II osteoporotic vertebral compression fractures which had been unresponsive to conservative treatment for at least eight weeks. We also examined the quality of life (QoL). The clinical follow-up involved the use of a pain intensity numerical rating scale (PI-NRS, 0 to 10), the Short-Form 36 (SF-36) QoL questionnaire and an anamnestic questionnaire before and at seven days (PI-NRS only), and one, three, 12 and 36 months post-operatively. A total of 30 consecutive patients received percutaneous vertebroplasty for 62 vertebral compression fractures with a mean time between fracture and treatment of 7.7 months (2.2 to 39). An immediate, significant and lasting reduction in the average and worst back pain was found, represented by a decrease of 3.1 and 2.7 points after seven days and 3.1 and 2.8 points after 36 months, respectively (p < 0.00). Comparison of the pre- and post-vertebroplasty scores on the various SF-36 domains showed an ultimate significant increase in six of eight domains and both summary scores. Asymptomatic leakage of cement was found in 47 of 58 (81%) of treated vertebrae. Two minor complications occurred, an asymptomatic pulmonary cement embolism and a cement spur along the needle track. Percutaneous vertebroplasty in the treatment of chronic vertebral compression fractures results in an immediate, significant and lasting reduction in back pain, and overall improvement in physical and mental health.

The Exeter femoral stem continues to migrate during its first decade after implantation 10-12 years of follow-up with radiostereometric analysis (RSA)

Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. Results After assessment of 10 557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15 384 implants in 13 164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200 000 of these implants. Reported comparative data with well established alternative devices (over 1 200 000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). Conclusion We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety.

Optimal Intravertebral Cement Volume in Percutaneous Vertebroplasty for Painful Osteoporotic Vertebral Compression Fractures

BACKGROUND Excessive early migration of femoral stems following total hip arthroplasty and tibial components following total knee arthroplasty is associated with their long-term survival and allows reliable early evaluation of implant performance. However, a similar relationship involving acetabular components following hip arthroplasty has not been evaluated. This prospective, long-term study with clinical and Roentgen stereophotogrammetric analysis (RSA) follow-up establishes the existence of this relationship and its associated diagnostic performance. METHODS Thirty-nine consecutive patients (forty-one hips) who underwent total hip arthroplasty with a cemented Exeter stem and a cemented Exeter all-polyethylene cup had prospective clinical and RSA follow-up. Patients were evaluated postoperatively at six weeks, at three, six, and twelve months, and annually thereafter. Conventional anteroposterior and lateral radiographs were made at six weeks and at two, five, and ten years postoperatively as well as when indicated. The mean duration of follow-up (and standard deviation) was 9.4 ± 3.2 years. No patients were lost to follow-up; fifteen patients died during the follow-up period. RESULTS Eleven acetabular components were observed to be loose on conventional radiographs after a mean of seventy-six months (range, twelve to 140 months). During the first two postoperative years, the failed acetabular components showed markedly greater and more rapid cranial translation and sagittal rotation. Both cranial translation (hazard ratio = 19.9 [95% confidence interval, 4.94 to 80.0], p < 0.001) and sagittal rotation (hazard ratio = 11.1 [95% confidence interval, 2.83 to 43.9], p = 0.001) were strong risk factors for late aseptic loosening. Eight of the eleven failed components showed a distinctive pattern of excessive cranial translation combined with excessive sagittal rotation. The associated diagnostic performance of two-year cranial translation and/or sagittal rotation for predicting late aseptic loosening of the acetabular component was good (area under the receiver operating characteristic curve, 0.88 [95% confidence interval, 0.74 to 1.00; p < 0.001] and 0.84 [95% confidence interval, 0.68 to 1.00; p = 0.001], respectively). CONCLUSIONS Early migration, as measured by RSA at two years postoperatively, has good diagnostic capabilities for the detection of acetabular components at risk for future aseptic loosening, and this method appears to be an appropriate means of assessing the performance of new implants or implant-related changes.

New Vertebral Fractures after Percutaneous Vertebroplasty for Painful Osteoporotic Vertebral Compression Fractures: A Clustered Analysis and the Relevance of Intradiskal Cement Leakage

Background Due to its collarless, double-tapered polished design, the Exeter femoral stem is known to migrate distally in the first 5 years after implantation. However, its long-term migration pattern has not been investigated. Patients and methods 39 consecutive patients (41 total hip arthroplasties) received a cemented Exeter stem and had prospective clinical and RSA follow-up. Patients were evaluated postoperatively at 6, 12, 26, and 52 weeks, and annually thereafter. Short-term results have been reported. In this study, the mean length of follow-up was 9.4 years (SD 3.2 years). No patients were lost to follow-up. 15 patients died during follow-up. Results No stems were revised. In 4 stems, fractures of the cement mantle were noted within the first 3 postoperative years. In 3 stems, this resulted in a complete circumferential cement mantle discontinuity. For the 37 well-performing stems, continuous but small migration was measured between 2 and 12 years of follow-up. Continued subsidence of 0.08 mm/year (95% CI: 0.05–0.12, p < 0.001) was seen in combination with continued rotation in retroversion of 0.07°/year (95% CI: 0.02–0.12, p = 0.01). At 10 years of follow-up, mean subsidence was 2.1 (SD 1.2) mm and mean retroversion was 1.8° (SD 2.0). Two-thirds of this occurred during the first 2 postoperative years. In the 3 stems with a complete circumferential cement fracture, a sudden and disproportionately high increase in subsidence was measured in the time period of occurrence. Interpretation The Exeter femoral stem continues to migrate during the first decade after implantation. Absolute stability is not required for good long-term survival if this is compatible with the design of the implant.

Fixation of high-flexion total knee prostheses: five-year follow-up results of a four-arm randomized controlled clinical and roentgen stereophotogrammetric analysis study.

Study Design. A prospective follow-up study. Objective. Assessment of the relation between accomplishment of pain relief through percutaneous vertebroplasty (PVP) in painful osteoporotic vertebral compression fractures (OVCFs) and the cemented fraction of the vertebral body and subsequent determination of the optimal intravertebral cement volume. Summary of Background Data. The mechanism of pain relief of PVP as a treatment modality for painful OVCFs remains unclear. Generally, benefit of PVP is thought to result from stabilization of micromovements and collapse of the fractured vertebral body. However, studies indicating a relation between intravertebral cement volume and pain relief are lacking and an optimal value of the intravertebral cement volume is unknown. Methods. One hunderd six patients who received PVP for 196 painful OVCFs were prospectively followed on back pain (score 0–10) and occurrence of new OVCFs during the first postoperative year. Patients were classified as responders (average postoperative back pain ⩽6) and nonresponders (average postoperative back pain >6). The cemented fraction of the vertebral body was determined using volumetric analysis of the postoperative CT scan of the treated levels. Analysis was performed using receiver-operating characteristic (ROC) analysis and multivariable regression techniques. Results. Twenty-nine patients (27.3%) were found to be nonresponders. Mean intravertebral cement volume in all 196 treated OVCFs was 3.94 mL (SD = 1.89, range 0.13–10.8). The mean cemented vertebral body fraction was significantly lower in nonresponders (0.15 vs. 0.21, P = 0.002). The ROC area-under-curve of the cemented fraction as a predictor of accomplishment of pain relief was 0.67 (95% CI: 0.57–0.78, P = 0.006). In subgroups without specific influential factors (new OVCFs, intravertebral clefts), significantly stronger associations were found. A vertebral body fraction of 24% was identified as the optimal fraction to be cemented. This fraction corresponded to a 93% to 100% specificity for accomplishment of pain relief (i.e., few to no cases without pain relief in the presence of adequate cementing) without being significantly associated with a higher risk of occurrence of cement leakage or new OVCFs. Corresponding values for the recommended (optimal) intravertebral cement volume were provided based on its governing characteristics (fracture level, fracture severity, and patients sex). Conclusion. An optimal intravertebral cement volume was identified for accomplishment of pain relief through PVP in painful OVCFs. Appropriate thresholds were provided to guide the operator.