Hans Mau

Treatment of calcifying tendinitis of rotator cuff by extracorporeal shock waves: a preliminary report.

This study examined the effects of high-energy shock wave treatment on the course of calcifying tendinitis of the shoulder. Twenty patients were included in the protocol. Shock waves were applied to the calcifications with a lithotripter in two sessions of 2000 pulses each. The energy that produced the shock wave was 18 to 22 kV. Six and 12 weeks after treatment the subjective and functional state was assessed with the Constant score. All patients underwent radiographs and magnetic resonance imaging. At the 12-week follow-up evaluation 15 patients had a marked reduction of symptoms with an average of 30% improvement in the Constant score. Radiographs showed a complete elimination of the calcifications in seven patients, and in five cases a partial disintegration was seen. The overall morbidity was low; 14 patients had a transient subcutaneous hematoma. Magnetic resonance imaging did not show any lasting damage to bone or soft tissue.

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.

Molecular analysis of expansion, differentiation, and growth factor treatment of human chondrocytes identifies differentiation markers and growth-related genes

This study is intended to optimise expansion and differentiation of cultured human chondrocytes by growth factor application and to identify molecular markers to monitor their differentiation state. We dissected the molecular consequences of matrix release, monolayer, and 3D-alginate culture, growth factor optimised expansion, and re-differentiation protocols by gene expression analysis. Among 19 common cartilage molecules assessed by cDNA array, six proved best to monitor differentiation. Instant down-regulation at release of cells from the matrix was strongest for COL 2A1, fibromodulin, and PRELP while LUM, CHI3L1, and CHI3L2 were expansion-related. Both gene sets reflected the physiologic effects of the most potent growth-inducing (PDGF-BB) and proteoglycan-inducing (BMP-4) factors. Only CRTAC1 expression correlated with 2D/3D switches while the molecular phenotype of native chondrocytes was not restored. The markers and optimised protocols we suggest can help to improve cell therapy of cartilage defects and chondrocyte differentiation from stem cell sources.

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.

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.

Relationship between calcifying tendinitis and subacromial impingement: A prospective radiography and magnetic resonance imaging study

In a prospective study radiographs and magnetic resonance images of 75 patients with calcifying tendinitis of the rotator cuff were analyzed. The aim was to evaluate any relation between calcifying tendinitis and subacromial impingement. A total of 83% of the calcifications were located in the supraspinatus or the adjoining part of the subscapularis tendon. On T1-weighted images they could be demonstrated with high accuracy as areas of decreased signal intensity. A magnetic resonance imaging categorization of the calcium deposits was carried out by means of a differentiation of form, outline, and density. A partial rotator cuff tear was found in one shoulder; in 11% variable aspects of degenerative alteration of the affected tendon were seen. By analysis of the radiographic outlet view 16% of the cases had a type III acromion. In conclusion, little correlation exists between calcifying tendinitis and additional findings associated with subacromial impingement.

Identification of drug‐regulated genes in osteosarcoma cells

The introduction of systemic chemotherapy improved significantly the prognosis of osteosarcoma. Despite this success, approximately 30–40% of patients will relapse. Cytotoxic drugs have been shown to induce apoptosis in the target cells independent of their primary effects. The underlying molecular mechanisms and the intracellular mediators, however, are still largely unknown. Therefore, the purpose of our study was to identify drug‐regulated genes in osteosarcoma cells useful as prognostic factors and for the development of new therapeutic strategies. Using suppressive subtractive hybridization (SSH) the gene expression pattern of untreated Saos‐2 cells was compared to cells treated with cisplatin, methotrexate and doxorubicin, respectively. We identified 8 genes that are regulated >2‐fold in drug‐treated osteosarcoma cell lines. Expression of ferritin light chain, rhoA, inosine monophosphatdgehydrogenase II, ribonucleotide reductase M2, pro2000 and pro1859 were increased after drug treatment, whereas prohibitin and α‐actinin expressions were significantly downregulated. Differential expression of the identified genes was verified by Northern blot analysis of 3 different osteosarcoma cell lines. In addition, the effects on chemosensitivity of 4 selected genes was analyzed by overexpression of recombinant constructs in Saos‐2 cells and subsequent quantification of drug‐induced apoptosis. Overexpression of prohibitin and rhoA reduced significantly drug sensitivity to approximately 52% and 59% indicating a crucial role in the modulation of drug‐induced cell death.

Comparison of various vacuum mixing systems and bone cements as regards reliability, porosity and bending strength

Background There are several vacuum mixing systems on the market which are arbitrarily used with various bone cements in clinical work. Hardly any studies have been done on the performance and handling of these systems in combination with different cement brands.Material and methods We therefore tested 6 vacuum mixing systems (Palamix, Summit, Cemvac, Optivac, Vacumix, MixOR) in combination with 6 cement brands (Palacos R, Simplex P, CWM 1, CWM 2000, Palamed G, VersaBond) concerning their reliability, user-friendliness, porosity and bending strength.Results Our study indicated that each system has weak points. The preparation of the mixed cement for gun injection can present problems. If cement collection under vacuum fails, porosity is increased. Manual collection without a vacuum carries the risk of intermixing air. For comfortable and effective retrograde cement application, cement guns should have a stable connection with the cartridge and a high piston stroke. There are marked differences between the systems as regards overall porosity when all tested cements are considered (range 2–18%), and between the cements when all tested systems are considered (range 2–17%). All test samples exceeded the required bending strength of 50 MPa, according to ISO 5833. Palacos specimens showed excessive plastic deformation in the bending test.Interpretation There are better and worse mixing system/cement combinations for a given system and a given cement. Systems with cement collection under vacuum reduce porosity best.s

[Acetabular reinforcement rings in revision total hip arthroplasty: midterm results in 298 cases].

BACKGROUND Acetabular revision in total hip arthroplasty (THA), especially for loose or migrated cup components with collateral bone loss, remains a great surgical challenge. The aim should always be a functionally favorable reconstruction of the rotation center with sufficient load capacity of the acetabulum. Commonly used implants in Europe are the Mueller ring, the Ganz ring, and the Burch-Schneider cage. PATIENTS AND METHODS We report our results of 298 patients (298 hips) with a median follow-up period of 4 (range 0-17) years in a retrospective series. RESULTS Follow-up data were available in 224 cases (75%). A radiographic examination was performed in 176 (59%) patients. Another 54 patients (18%) had died in the follow-up period, while another three patients (1%) were lost to follow-up. Eighteen patients (16%) underwent re-revision, in nine cases for aseptic loosening and in the remaining nine cases for infection. In seven additional cases (2%), radiological and clinical failure was found during follow-up. The overall survival rate was 94% at 5 years and 89% at 8 years. CONCLUSION Revision THA using acetabular reinforcement rings results in acceptable midterm results. However, septic complications and lysis of the bone graft with consecutive failure of the reinforcement ring remain problematic.