Browsing by Subject "Prosthesis Failure"
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Item Open Access Are component positioning and prosthesis size associated with hip resurfacing failure?(BMC Musculoskelet Disord, 2010-10-02) Marker, David R; Zywiel, Michael G; Johnson, Aaron J; Seyler, Thorsten M; Mont, Michael ABACKGROUND: Recent studies suggest that there is a learning curve for metal-on-metal hip resurfacing. The purpose of this study was to assess whether implant positioning changed with surgeon experience and whether positioning and component sizing were associated with implant longevity. METHODS: We evaluated the first 361 consecutive hip resurfacings performed by a single surgeon, which had a mean follow-up of 59 months (range, 28 to 87 months). Pre and post-operative radiographs were assessed to determine the inclination of the acetabular component, as well as the sagittal and coronal femoral stem-neck angles. Changes in the precision of component placement were determined by assessing changes in the standard deviation of each measurement using variance ratio and linear regression analysis. Additionally, the cup and stem-shaft angles as well as component sizes were compared between the 31 hips that failed over the follow-up period and the surviving components to assess for any differences that might have been associated with an increased risk for failure. RESULTS: Surgeon experience was correlated with improved precision of the antero-posterior and lateral positioning of the femoral component. However, femoral and acetabular radiographic implant positioning angles were not different between the surviving hips and failures. The failures had smaller mean femoral component diameters as compared to the non-failure group (44 versus 47 millimeters). CONCLUSIONS: These results suggest that there may be differences in implant positioning in early versus late learning curve procedures, but that in the absence of recognized risk factors such as intra-operative notching of the femoral neck and cup inclination in excess of 50 degrees, component positioning does not appear to be associated with failure. Nevertheless, surgeons should exercise caution in operating patients with small femoral necks, especially when they are early in the learning curve.Item Open Access Implant healing in experimental animal models of diabetes.(J Diabetes Sci Technol, 2011-05-01) Le, NN; Rose, MB; Levinson, H; Klitzman, BDiabetes mellitus is becoming increasingly prevalent worldwide. Additionally, there is an increasing number of patients receiving implantable devices such as glucose sensors and orthopedic implants. Thus, it is likely that the number of diabetic patients receiving these devices will also increase. Even though implantable medical devices are considered biocompatible by the Food and Drug Administration, the adverse tissue healing that occurs adjacent to these foreign objects is a leading cause of their failure. This foreign body response leads to fibrosis, encapsulation of the device, and a reduction or cessation of device performance. A second adverse event is microbial infection of implanted devices, which can lead to persistent local and systemic infections and also exacerbates the fibrotic response. Nearly half of all nosocomial infections are associated with the presence of an indwelling medical device. Events associated with both the foreign body response and implant infection can necessitate device removal and may lead to amputation, which is associated with significant morbidity and cost. Diabetes mellitus is generally indicated as a risk factor for the infection of a variety of implants such as prosthetic joints, pacemakers, implantable cardioverter defibrillators, penile implants, and urinary catheters. Implant infection rates in diabetic patients vary depending upon the implant and the microorganism, however, for example, diabetes was found to be a significant variable associated with a nearly 7.2% infection rate for implantable cardioverter defibrillators by the microorganism Candida albicans. While research has elucidated many of the altered mechanisms of diabetic cutaneous wound healing, the internal healing adjacent to indwelling medical devices in a diabetic model has rarely been studied. Understanding this healing process is crucial to facilitating improved device design. The purpose of this article is to summarize the physiologic factors that influence wound healing and infection in diabetic patients, to review research concerning diabetes and biomedical implants and device infection, and to critically analyze which diabetic animal model might be advantageous for assessing internal healing adjacent to implanted devices.Item Open Access Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity.(Journal of neurosurgery. Spine, 2014-12) Smith, Justin S; Shaffrey, Ellen; Klineberg, Eric; Shaffrey, Christopher I; Lafage, Virginie; Schwab, Frank J; Protopsaltis, Themistocles; Scheer, Justin K; Mundis, Gregory M; Fu, Kai-Ming G; Gupta, Munish C; Hostin, Richard; Deviren, Vedat; Kebaish, Khaled; Hart, Robert; Burton, Douglas C; Line, Breton; Bess, Shay; Ames, Christopher P; International Spine Study GroupObject
Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.Methods
This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.Results
Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).Conclusions
Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.Item Open Access The Fate of Patients with Adult Spinal Deformity Incurring Rod Fracture After Thoracolumbar Fusion.(World neurosurgery, 2017-10) Hamilton, D Kojo; Buza, John A; Passias, Peter; Jalai, Cyrus; Kim, Han Jo; Ailon, Tamir; Gupta, Munish; Sciubba, Daniel; Jain, Amit; Ames, Christopher P; Deviren, Vedat; Daniels, Alan; Lafage, Virginie; Bess, Shay; Klineberg, Eric; Shaffrey, Christopher I; Smith, Justin S; Hart, Robert; International Spine Study GroupObjective
To report the outcome of adult spinal deformity (ASD) in patients with rod fracture (RF) after thoracolumbar fusion.Methods
Retrospective review of prospective, multicenter database. Operative patients with ASD ≥18 years old with RF after ASD surgery and with a minimum 6-month follow-up after RF were included. Health-related quality of life scores and radiographic alignment were compared with nonparametric paired and independent testing (P < 0.05).Results
A total of 51 of 343 patients with ASD (14.9%) sustained a RF, of whom 44 (86.3%) had at least 6-month follow up after RF (mean age = 61.2 years, mean body mass index = 29.6 kg/m2). Mean total follow-up was 37.8 months (range 24.5-66.7 months). Interbody fusion was used in 26 cases of RF (59.1%) (transforaminal lumbar interbody fusion, n = 17 [65.4%], anterior lumbar interbody fusion, n = 5 [19.2%]). RF was symptomatic in 26 of 44 (59.1%) of patients and discovered incidentally in 18 of 44 patients (40.9%). Overall, 28 RFs were revised (63.6%); 12 of 23 (52.2%) unilateral RF and 16 of 21 (76.2%) bilateral RF at last follow-up. Revision patients were significantly more likely to be symptomatic at the time of RF detection (78.6% vs. 25.0%, P = 0.0006), and had significantly worse Oswestry Disability Index and Scoliosis Research Society-22r pain scores.Conclusions
RFs were detected in 14.9% of patients with ASD and were most common at the L4-L5 and L5-S1 levels. Approximately 63.6% of patients underwent revision surgery. The decision to perform revision surgery may be based predominantly on symptoms referable to the RF, pain, and perceived disability, as radiographic parameters at the time of RF did not differ significantly between patients who did and did not undergo revision.