Steffen Breusch

Pattern of Periprosthetic Bone Remodeling Around Stable Uncemented Tapered Hip Stems: A prospective 84-month follow-up study and a Median 156-month Cross-Sectional Study with DXA

Bone resorption in the proximal femur is commonly seen after total hip arthroplasty (THA). With dual energy X-ray absorptiometry (DXA), the amount of bone mass (BMD) after implantation of a total hip stem can be precisely determined. However, prospective evaluation of the change of bone mass around the stem is only available for selected stems and short-term follow-up (up to 36 months). We analyzed BMD in patients who had undergone uncemented THA by DXA. Only patients with good clinical outcome (Merle d’ Aubigné score > 12) were included to obtain normative data for regular bone response. Two separate studies were performed: a prospective longitudinal study over 84 months with baseline values acquired within the first postoperative week (group A) (n = 26 patients) and a separate cross-sectional study, median follow-up 156 (124-178) months (group B) (n = 35 patients). Regions of interest were defined according to Gruen (ROI 1-7) and as net average ROI (net avg) for the periprosthetic femoral bone. After the initial remodeling process (12 months), BMD was compared to the 84-month (longitudinal) and the 156-month (cross-sectional) follow-up values to determine long-term periprosthetic changes of bone mineral density. The longitudinal study (group A), after the initial bone remodeling, showed no relevant further bone loss for women and men with BMD values 1.19 ± 0.15 and 1.40 ± 0.19, respectively, 12 months (women 89.8%, men 93.6%), and 1.19 ± 0.13 and 1.36 ± 0.18, respectively, after 84 months (women 90.0%, men 91.3%) (P = 0.98, P = 0.08,) respectively. The distribution of the BMD around the stem changed during the first 12 months. The ROIs around the proximal stem (ROI 1 and 7) showed the lowest absolute values at the 12-month follow-up and BMD in ROI 7 decreased most during the further follow-up until 84 months. The cross-sectional study (group B) showed no significant difference in BMD (net avg) values at a median of 156 months follow-up compared to the 12-month values (group A) (women: P = 0.77, men: P = 0.44). Initial BMD, implant diameter, and body mass index did not influence BMD loss (net avg) in this study, whereas age showed a weak correlation with BMD loss. The results show that after the initial remodeling process, no relevant further bone loss (net avg) occurs up to 84 months postsurgery, and values after a median of 156 months are similar. Normative long-term changes in the periprosthetic bone can be demonstrated in defined ROIs after implantation of a tapered corundum-blasted titanium stem with a good clinical result.

Cementless Spotorno tapered titanium stems: Excellent 10-15-year survival in 141 young patients

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13-55)) years. After a mean follow-up of 12 (10-15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision-1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%-100%), and survival with femoral revision for aseptic loosening as an end point 98 (95-100)%. The survival rate of the acetabular components was 78 (71-85)% after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2-6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected. The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.

Uncemented Grit-Blasted Straight Tapered Titanium Stems in Patients Younger than Fifty-five Years of Age: Fifteen to Twenty-Year Results

BACKGROUND Total hip arthroplasty without cement is frequently performed in young active patients, but only limited outcomes data are available after durations of follow-up of more than fifteen years. METHODS We retrospectively evaluated the clinical and radiographic results of a consecutive series of 154 total hip arthroplasties (in 141 patients) performed with an uncemented grit-blasted straight tapered titanium femoral stem combined with a threaded socket in patients under the age of fifty-five years. The median duration of follow-up was seventeen years. Clinical results were evaluated with use of the Harris hip score. The canal fill index was used as the criterion to determine the adequacy of stem sizing. Kaplan-Meier survivorship analysis was performed to predict long-term outcomes. RESULTS The stem was undersized, with a canal fill index of < or =80%, in forty-one hips (27%). Late aseptic loosening of the stem occurred in four femora, and the femoral component was undersized in all four. These four stems were stable for ten years and then underwent progressive subsidence, which was associated with pain. Five stems were revised because of a late postoperative periprosthetic fracture following trauma. Localized proximal femoral osteolysis was seen in seven hips without signs of loosening. Survivorship of the stem with revision for any reason as the end point was estimated to be 90% (95% confidence interval, 87% to 97%) at twenty years. Survivorship with aseptic loosening as the end point was estimated to be 95% (95% confidence interval, 91% to 99%) at twenty years. Sixty-seven (44%) of the threaded uncemented acetabular components were revised during the follow-up period. CONCLUSIONS After a minimum duration of follow-up of fifteen years, the survival of this type of femoral component is excellent in individuals younger than fifty-five years. The main mode of stem failure was a periprosthetic fracture due to trauma, or late aseptic loosening in a small percentage of the hips in which the femoral implant was undersized. The high rate of failure of the acetabular components was attributable to a poor design that is no longer in use.

Enhanced expression of the human chitinase 3-like 2 gene (YKL-39) but not chitinase 3-like 1 gene (YKL-40) in osteoarthritic cartilage

The knowledge of molecular alterations in osteoarthritic cartilage is important to identify novel therapeutic targets or to develop new diagnostic tools. We aimed to characterize the molecular response to cartilage degeneration by identification of differentially expressed genes in human osteoarthritic versus normal cartilage. Gene fragments selectively amplified in osteoarthritic cartilage by cDNA representational difference analysis included YKL-39 and the oesophageal-cancer-related-gene-4 (ECRG4). YKL-39 expression was significantly upregulated in cartilage from patients with osteoarthritis (n=14) versus normal subjects (n=8) according to real-time PCR (19-fold, p=0.009) and cDNA array analysis (mean 15-fold, p<0.001) and correlated with collagen 2 up-regulation. In contrast, the homologous cousin molecule YKL-40 (chitinase 3-like 1), which is elevated in serum and synovial fluid of patients with arthritis, showed no significant regulation in OA cartilage. Enhanced levels of YKL-40 may, therefore, be derived from synovial cells while modulation of YKL-39 and collagen 2 expression reflected the cartilage metabolism in response to degradation.

Influence of cement viscosity on cement interdigitation and venous fat content under in vivo conditions

In a sheep model permitting standardized bilateral, simultaneous cement pressurization, we studied the effect of different cement viscosities on fat and bone marrow intravasation and cement penetration in vivo. High viscosity cement (Palacos) was used on one side and low viscosity cement (Osteopal) on the other. Catheters were inserted into both external iliac veins to collect blood during bilateral simultaneous cement pressurization. After bone preparation and pulsatile lavage, both femora were filled with cement followed by simultaneous cement pressurization. A quantitative fat analysis of the blood collected was done. We used microradiographs to determine cement penetration in a left versus right comparison of both viscosity groups. The low viscosity cement yielded lower rates of cement penetration despite adequate and sustained pressurization. Cement applied at low viscosity state seems to take the path of least resistance into the venous system before more deeper cement penetration can occur. The use of high viscosity cement ran a higher risk of fat embolism, but improved cement interdigitation.

Cementless Spotorno tapered titanium stems

We evaluated the clinical and radiographic results of the first consecutive 154 implantations of a cementless, double-tapered straight femoral stem (cementless Spotorno (CLS), Sulzer Orthopedics) in 141 patients under the age of 55 (mean 47 (13–55)) years. After a mean follow-up of 12 (10–15) years, 11 patients (11 hips) had died and 7 (7 hips) could not be located. 5 patients (5 hips) underwent femoral revision—1 for infection, 1 for periprosthetic fracture and 3 for aseptic loosening of the stem. The overall survival rate of the stem was 97% at 12 years (95% confidence limits, 93%–100%), and survival with femoral revision for aseptic loosening as an end point 98 (95–100)%. The survival rate of the acetabular components was 78 (71–85) % after 12 years. The median Harris hip score at follow-up was 84 points. None of the patients had thigh pain. Radiolucent lines in Gruen regions 1 and 7 were present in 21 hips (17%). 2 hips had radiolucent lines in regions 2–6 on anteroposterior (AP) radiographs. No femoral osteolysis was detected. The mid- to long-term survival with this type of femoral component is excellent and compares favorably with cemented stems in this age group. However, the high rate of cup loosening and the low Harris hip scores are a concern in this subgroup of young patients.

Metal-on-metal hip resurfacing: a critical review

In this article, a concise review of the current literature on metal-on-metal hip resurfacing (MoMHR) is given. In contrast to conventional total hip arthroplasty, older age, female sex and small femoral head sizes predispose to failure. Neck fracture and metal wear-related complications account for the most frequent reasons for re-operations. Although the long-term consequences of metal ion release remain unknown, the increasing prevalence of soft tissue related problems with potentially devastating functional consequences in this younger patient group are of concern. Outcome after revision for metal wear related failure of MoMHR is poor. In our opinion, patients with this device should be managed in dedicated centers with facilities for data collection and monitoring. The majority of proposed advantages of MoMHR cannot be supported by the published evidence.

Deep infection after hip fracture surgery: Predictors of early mortality

INTRODUCTION This study analysed the predictors of mortality in patients who are diagnosed with deep infection following hip fracture surgery. METHODS Data were prospectively collected for 3 years from all patients undergoing hip fracture surgery and who had developed a subsequent deep infection. Infection was defined as positive microbiology culture from deep tissue or fluid samples. Demographic data, treatment, complications and subsequent surgeries were analysed. Potential predisposing factors including chronic medical co-morbidities, American Society of Anesthesiologists (ASA) grade, alcohol excess and smoking were assessed. The main outcome measures were 30-day and 1-year mortality. RESULTS There were 2718 consecutive operations performed for a fracture of the proximal femur over a 3-year period. Forty-three (1.6%) patients had a deep postoperative infection diagnosed on fluid and/or tissue sampling. The mean age was 73 years (25-94) and 65% were female. Of the 43 patients who developed deep infection, the primary procedure in 25 (58%) patients was reduction and internal fixation, with 18 (42%) undergoing hemi-arthroplasty. The most common causative organism was Staphylococcus epidermidis (n=13, 30%), with methicillin-resistant Staphylococcus aureus (MRSA) accounting for 23% (n=10). The 30-day mortality was significantly higher than that of patients with no deep infection (19% vs. 6.5%; p=0.004). On univariate analysis, increasing age, dementia and diabetes were predictive of both 30-day and 1-year mortality (all p<0.05). S. aureus (sensitive or resistant) was approaching significance at 1 year (p=0.065). On multivariate analysis, dementia and diabetes were independent predictors of 30-day mortality, with dementia and S. aureus predictive at 1 year. CONCLUSIONS The 30-day mortality rate in patients diagnosed with deep infection following hip fracture surgery is higher than those without infection. Dementia, diabetes and S. aureus infection are independent predictors of mortality following deep infection.

Increased urinary crosslink levels in aseptic loosening of total hip arthroplasty

The diagnosis of aseptic loosening in total hip arthroplasty is predominantly based on clinical and radiographic evaluation. Loosening is usually associated with increased bone resorption at the interface. In this study we wanted to evaluate the diagnostic value of bone markers in aseptic loosening. We compared 50 patients with proven component loosening during surgery with 50 age-, sex-, and implant-matched patients without clinical or radiological signs of loosening. We measured serum markers of bone formation (bone-specific alkaline phosphatase, osteocalcin [OC], procollagen type I propeptides) and bone resorption (collagen n-telopeptide [NTX], deoxypyridinoline [DPYD], pyridinoline [PYD]). We found significantly increased levels of NTX, DPYD, PYD, and OC in the loosening group. The other markers showed no significant difference between both groups. We conclude that determination of urinary crosslinks may offer a new and valuable diagnostic method in the detection of aseptic loosening in total hip arthroplasty.

Efficacy of vacuum bone cement mixing systems in reducing methylmethacrylate fume exposure: comparison of 7 different mixing devices and handmixing.

Background Polymethylmethacrylate (PMMA) bone cements are mainly used for implant fixation in joint replacement surgery. During cement preparation for application, all staff in the operating theatre are exposed to methylmethacrylate (MMA) fumes, which are known to have toxic side effects.Methods and results In this study we found that vacuum mixing of bone cement with 7 commercially available mixing devices significantly reduced the emission of MMA vapors in the breathing zone when compared with classic hand mixing in an open bowl. Gas chromatography appears to be more sensitive for detection of MMA fumes than Photo Inonization Detection.Interpretation According to present knowledge, even repeated mixing of PMMA bone cement during a normal working day does not seem to constitute an increased health risk, particularly if vacuum mixing is implemented.