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Joachim Grifka

Publications and source records attributed to Joachim Grifka.

At least 19 recordsLinked to original sources
PubMed2006

Collagen IX is indispensable for timely maturation of cartilage during fracture repair in mice.

Fracture repair recapitulates in adult organisms the sequence of cell biological events of endochondral ossification during skeletal development and growth. After initial inflammation and deposition of granulation tissue, a cartilaginous callus is formed which, subsequently, is remodeled into bone. In part, bone formation is influenced also by the properties of the extracellular matrix of the cartilaginous callus. Deletion of individual macromolecular components can alter extracellular matrix suprastructures, and hence stability and organization of mesenchymal tissues. Here, we took advantage of the collagen IX knockout mouse model to better understand the role of this collagen for organization, differentiation and maturation of a cartilaginous template during formation of new bone. Although a seemingly crucial component of cartilage fibrils is missing, collagen IX-deficient mice develop normally, but are predisposed to premature joint cartilage degeneration. However, we show here that lack of collagen IX alters the time course of callus differentiation during bone fracture healing. The maturation of cartilage matrix was delayed in collagen IX-deficient mice calli as judged by collagen X expression during the repair phase and the total amount of cartilage matrix was reduced. Entering the remodeling phase of fracture healing, Col9a1(-/-) calli retained a larger percentage of cartilage matrix than in wild type indicating also a delayed formation of new bone. We concluded that endochondral bone formation can occur in collagen IX knockout mice but is impaired under conditions of stress, such as the repair of an unfixed fractured long bone.

Animals↗
PubMed2006

MR imaging of the intraarticular disk of the acromioclavicular joint: a comparison with anatomical, histological and in-vivo findings.

OBJECTIVE: To characterize MRI features of the intraarticular disk of the acromioclavicular joint. DESIGN: We studied the appearance of 11 acromioclavicular joints of six cadavers (subjects aged 57-89 years at the time of death) and six healthy shoulders on T1-weighted, T2 (TSE)-weighted, STIR and PD (fat saturated) magnetic resonance imaging (MRI) and compared the findings with observations during dissection and histological examination. RESULTS: Macroscopic examinations showed two wedge-shaped disks underneath the superior and above the inferior joint capsule in nine specimens. In two specimens the acromioclavicular joints were degenerated. Histologically, the disk tissue consisted of fibrocartilage whereas the joint cartilage was partly degenerated, containing zones of fibrocartilage amidst degenerated hyaline cartilage, which may explain the similar signal intensity of both structures in all sequences used. MR appearance of the intraarticular structures of the acromioclavicular joint was similar in cadaveric and healthy shoulders. CONCLUSIONS: The difficulties related to imaging the acromioclavicular joint may be explained by the anatomy. Similar signal intensity of cartilage and disk may be explained by their similar histological structure (fibrocartilage). MRI findings should be interpreted with respect to the variable anatomy. These results may serve as a basis for further radiological studies of the acromioclavicular joint.

Acromioclavicular Joint↗
PubMed2006

Collagen XVI harbors an integrin alpha1 beta1 recognition site in its C-terminal domains.

Collagen XVI is integrated tissue-dependently into distinct fibrillar aggregates, such as D-banded cartilage fibrils and fibrillin-1-containing microfibrils. In skin, the distribution of collagen XVI overlaps that of the collagen-binding integrins alpha1 beta1 and alpha2 beta1. Basal layer keratinocytes express integrin alpha2 beta1, whereas integrin alpha1 beta1 occurs in smooth muscle cells surrounding blood vessels, in hair follicles, and on adipocytes. Cells bearing the integrins alpha1 beta1 and alpha2 beta1 attach and spread on recombinant collagen XVI. Furthermore, collagen XVI induces the recruitment of these integrins into focal adhesion plaques, a principal step in integrin signaling. Of potential physiological relevance, these integrin-collagen XVI interactions may connect cells with specialized fibrils, thus contributing to the organization of fibrillar and cellular components within connective tissues. In cell-free binding assays, collagen XVI is more avidly bound by alpha1 beta1 integrin than by alpha2 beta1 integrin. Both integrins interact with collagen XVI via the A domain of their alpha subunits. A tryptic collagen XVI fragment comprising the collagenous domains 1-3 is recognized by alpha1 beta1 integrin. Electron microscopy of complexes of alpha1 beta1 integrin with this tryptic collagen XVI fragment or with full-length collagen XVI revealed a unique alpha1 beta1 integrin-binding site within collagen XVI located close to its C-terminal end.

Adipocytes↗
PubMed2006

The effectiveness of sequential medial soft tissue release on coronal alignment in total knee arthroplasty: using a computer navigation model.

Soft tissue management is a major step in total knee arthroplasty. We aimed to analyze the relationship between sequential medial soft tissue release and the resulting change in the anteroposterior limb axis and the tibiofemoral gaps. Measurements were obtained using a CT-free navigation system (Ci navigation system, DePuy I-Orthopaedics, Munich, Germany). Concerning leg axis, each release step led to significant (P < .001) effects. The highest effect was seen for the 6-cm release in extension and the release of medial collateral ligament in 90 degrees flexion. The medial gap difference was significant for each release step except the 4-cm release in extension. The highest increase resulted when sacrificing the entire posterior cruciate ligament in extension and in 90 degrees flexion. Implementation of computer-assisted surgery allows this first navigation-controlled study, elucidating the effect of soft tissue release in total knee arthroplasty.

Adolescent↗
PubMed2006

Gap configuration and anteroposterior leg axis after sequential medial ligament release in rotating-platform total knee arthroplasty.

BACKGROUND: Soft tissue management is a major issue in total knee replacement. There have been very few papers dealing with its effect on leg axis and tibiofemoral gap. METHODS: In a cadaver specimen study, we analyzed this effect by performing a sequential medial soft tissue release after a mobile-bearing total knee arthroplasty. Measurements were obtained using a CT-free navigation system (Ci navigation system). RESULTS: We found the highest increase in leg axis and medial gap when releasing the anteromedial tibial sleeve of the capsule 6 cm below the joint line, in extension, and after dividing the medial collateral ligament, in flexion, when releasing the medial half of the posterior cruciate ligament. There were differences in amount of change between extension and flexion, especially when releasing the medial half of the posterior cruciate ligament. In extension, the lateral gap remained the same as in flexion. INTERPRETATION: Implementation of computer-assisted surgery has allowed this first navigation-controlled study investigating the effect of soft tissue release in TKR with rotating platform. Each sequential release step has the desired effect on a.p. leg axis and tibiofemoral gaps. It is important that the differences between the effects in extension and flexion be noted.

Aged↗
PubMed2006

Moxifloxacin superior to vancomycin for treatment of bone infections--a study in rats.

BACKGROUND: Increasing resistance rates towards conventional antibiotics necessitate investigations of the efficacy of newly developed antibiotics. Thus, in a rat study, we compared the efficacy of moxifloxacin and vancomycin in the treatment of a local Staphylococcus aureus bone infection. METHOD: The femoral medullary cavities of 36 Wistar rats were contaminated with 100 muL of an oxacillin-sensitive Staphylococcus aureus strain (ATCC 29213) at 10(8) cfu/mL. On the seventh day, antibiotic treatment with moxifloxacin (10 mg/kg twice daily i.p.) or vancomycin (15 mg/kg twice daily i.p.) was commenced in 12 animals each. 12 control animals were left untreated. After 21 days, the infected femurs were explanted and the bacterial counts (cfu/g) were determined. RESULTS: In the control group, a median of 3.42 x 10(6) cfu/g (LQ/UQ 1.09 x 10(6)/ 1.55 x 10(7)) was cultured, with a median of 2.53 x 10(6) cfu/g (LQ/UQ 1.95 x 10(6)/ 4.25 x 10(6)) in the vancomycin group and a median of 2.49 x 10(5) cfu/g (LQ/UQ 2.84 x 10(4)/ 3.75 x 10(5)) in the moxifloxacin group. The bacterial count was reduced by treatment with moxifloxacin both in comparison with the control group (p < 0.001), and in comparison with treatment with vancomycin (p < 0.001). There was no statistically significant difference between the vancomycin group and the control group (p = 0.53). INTERPRETATION: In contrast to vancomycin, moxifloxacin proved to be an effective antibiotic for the treatment of bone infections due to Staphylococcus aureus in our animal model.

Animals↗
PubMed2006

Stability of pedicle screws after kyphoplasty augmentation: an experimental study to compare transpedicular screw fixation in soft and cured kyphoplasty cement.

OBJECTIVE: The goal of this cadaver study was to compare the stability of pedicle screws after implantation in soft or cured kyphoplasty cement. METHODS: Pedicle screws were inserted in a total of 30 thoracolumbar vertebrae of 10 different human specimens: 10 screws were implanted in nonaugmented vertebrae (group 1), each 10 screws were placed in soft (group 2) and cured (group 3) cement. Pedicle screws were than evaluated for biomechanical axial pullout resistance. RESULTS: Mean axial pullout strength was 232 N (range 60-600 N) in group 1, 452 N (range 60-1125 N) in group 2 and 367 N (range 112-840 N) in group 3. The paired Student t-test demonstrated a significant difference between pullout strength of groups 1 and 2 (P = 0.0300). Between pullout strength of groups 1 and 3 and between groups 2 and 3 no significant difference was seen. CONCLUSION: We achieved a 1.9 times higher pullout strength with kyphoplasty augmentation of osteoporotic vertebrae compared with the pullout strength of nonaugmented vertebrae. Implantation of pedicle screws in cured cement is a sufficient method. With this method we found a 1.6 times higher pullout strength then in nonaugmented vertebrae.

Adhesiveness↗
PubMed2006

CD45-positive cells of haematopoietic origin enhance chondrogenic marker gene expression in rat marrow stromal cells.

Adult mesenchymal stem cells (MSCs) can be readily isolated from bone marrow, expanded in culture and subsequently subjected to differentiation into various connective tissue lineages. In general, for animal studies separation of MSCs from other bone marrow-derived cells is achieved by sole adherence to plastic surface of tissue culture flasks; however, this procedure produces a heterogeneous cell population containing CD45-positive haematopoietic cells (HCs) and haematopoietic stem cells (HSCs). It is known, that mixed cell cultures consisting of cocultures of differentiated somatic cells with adult stem cells promote differentiation towards specific cell lineages. For determining the effect of the CD45-positive cell population on the differentiation potential of MSCs, we sorted out the bone marrow-derived adherent cells by immunomagnetic technique (MACS) to attain a subpopulation of CD45-depleted cells. Herein, we show that the presence of adherent CD45-positive HCs not only promote expression of the chondrogenic marker genes Col2a1, COMP and Sox9, but also of Col1a1, Col10a1 and to a certain degree Cbfa1 in MSCs when cultured in an appropriate three-dimensional environment. These observations constitute a step towards unravelling the influence of haematopoietic cells on chondrogenic differentiation of MSCs.

Animals↗
PubMed2005

Position of the acetabular cup -- accuracy of radiographic calculation compared to CT-based measurement.

OBJECTIVE: A variety of mathematical and trigonometric methods has been described for determining the position of the acetabular cups from conventional radiographs. However, these formulae are subject to unduly large inaccuracies. The aim of the study was to compare the reliability and the accuracy of radiological and CT-based determination of acetabular cup position. MATERIALS AND METHODS: The positions of acetabular cups of 31 patients were calculated in conventional plain radiographs of the hip using the method described by Widmer. Further, in all patients computed tomograms of the pelvis were performed and the cup position was measured with the aid of a CT-based computer-assisted navigation software. As reference values inclination and anteversion of the cups were calculated in 3D reconstructions of the pelvis with the aid of an image processing software. RESULTS: The radiological measurement as well as the CT-based method showed good intra- and inter-observer reliability and no significant difference in the calculation of the inclination (p=0.409). However, CT-based determination of anteversion was significantly more exact than radiological measurement (p<0.001). The calculation of the cup anteversion from the X-rays showed serious deviations from the reference method and a substantial error range (X-ray: mean deviation +1.74 degrees, range -16.6 degrees to +29.8 degrees , S.D. +/-9.32 degrees; CT-based: mean deviation -0.74 degrees, range -6.6 degrees to +5.3 degrees, S.D. +/-2.87). CONCLUSION: For any clinical problem or for clinical studies in which acetabular positions of acetabular cups have to be exactly determined, CT-based measuring methods are obviously the method of choice. Evaluations based only on conventional plain X-rays and calculation of the acetabular cup position using the formula described by Widmer must be regarded as unreliable, particularly, because of problems in measuring the anteversion.

Acetabulum↗
PubMed2005

Midvastus approach in total knee arthroplasty: a randomized, double-blinded study on early rehabilitation.

The medial parapatellar approach has become the standard technique in total knee arthroplasty (TKA). However, recent studies have reported superior results regarding functional recovery when using the midvastus approach. It was the aim of this study to evaluate the early functional outcome of both surgical techniques. In a prospective, double-blinded, randomized study, 50 patients for TKA were consecutively operated on either by the medial parapatellar or the midvastus approach. Exclusion criteria were defined as previous open knee surgery and leg deformity of more than 10 degrees varus or valgus. TKA was performed in all patients by one surgeon using the same type of implants in both groups. Pain scores (VAS) were documented and follow-up data including quadriceps strength and proprioception were obtained 3 weeks and 6 weeks postoperatively. Both groups were comparable in preoperative demographic data. Postoperatively, patients in the midvastus group demonstrated significantly lower pain in rest (VAS: mean 2.25 vs. 3.03) and under movement (VAS: mean 2.92 vs. 3.13). Further, they showed superior isometric quadriceps strength at 3 weeks (41.4 vs. 27.6 Nm) and 6 weeks (47.6 vs. 35.5 Nm). Moreover, this group showed a superior postoperative proprioception, while the range of motion was similar in both groups. The midvastus approach offers advantages over the standard parapatellar arthrotomy, in the early rehabilitation period. No adverse effects were observed associated with this approach. Therefore, the midvastus approach should be considered as a valuable alternative in TKA.

Aged↗
PubMed2005

Arthroscopic and histologic findings in Morquio's syndrome.

Mucopolysaccharidosis type IV A/B (Morquio's syndrome) is one of a heterogeneous group of lysosomal storage diseases characterized by accumulation of keratan sulfate in cells of connective tissue. From early childhood, the major orthopaedic manifestations are shortening of the trunk, spondylepiphyseal dysplasia, odontoid hypoplasia, upper cervical instability, lower-limb alignment problems, and degenerative joint disease. Most of the rare published case reports describe those characteristic clinical deformities of the skeleton. Our literature search showed that these striking arthroscopic findings have not been made public to date. We report a typical case of mucopolysaccharidosis type IV. We show and, in particular, correlate the arthroscopic with the histologic findings. In particular, the comparison between arthroscopy and light microscopy showed a remarkable extensive delamination of the chondral layer from subchondral bone of both knee joints. These findings should encourage further research, especially of the osteochondral borderline.

Adult↗
PubMed2005

Contaminant seeding in bone by different irrigation methods: an experimental study.

OBJECTIVE: This study was designed to investigate the effectiveness of using various devices and manual procedures for cleansing bacterially contaminated bone tissue and to assess the risk of iatrogenic bacterial seeding in deep bone layers. METHODS: In an in vitro model, human femoral heads were contaminated with Escherichia coli and then cleansed with pulsatile high-pressure lavage, pulsatile low-pressure lavage, manual rinsing with bulb syringe lavage, or manual rinsing with combined brush cleaning. The numbers of bacteria that remained or those that were introduced by the rinsing procedures were quantitatively determined at depths of 0 to 1 cm, 1 to 2 cm, and 2 to 3 cm. RESULTS: Both pulsatile high-pressure lavage and brush cleaning were more effective than pulsatile low-pressure lavage and bulb syringe lavage for the purpose of surface cleansing. The differences were highly significant (P < 0.001). There was no significant difference in the decontaminating effect between pulsatile high-pressure lavage and brush cleaning (P = 0.24). The bacterial contamination attributable to the cleansing procedure, as measured at tissue depths of 1 to 2 cm and 2 to 3 cm, was significantly higher after pulsatile high-pressure lavage and after pulsatile low-pressure lavage than it was after bulb syringe lavage or brush cleaning (P < 0.001). CONCLUSION: In this in vitro investigation of cancellous bone, the brush cleansing was just as effective for getting rid of bacterial contamination as pulsatile high-pressure lavage, and carries a significantly lesser risk of iatrogenic bacterial seeding into deeper tissue layers. In the light of these promising results obtained by the cleansing of cancellous bone contaminated with bacteria, it would be desirable to perform supplementary in vitro and in vivo investigations into brush cleansing.

Aged↗
PubMed2004

Revision total knee arthroplasty: a comparison of postoperative leg alignment after computer-assisted implantation versus the conventional technique.

Accurate reconstruction of leg alignment is one important factor for long-term survival in total knee arthroplasty (TKA). Recent developments in computer-assisted surgery focused on systems improving TKA. The aim of the study is to compare the results of computer-assisted revision TKA with the conventional technique. We hypothesize that a significantly better leg alignment and component orientation is achieved when using a navigation system for revision TKA. In a prospective study, two groups of 25 revision TKAs each were operated on using either a CT-free navigation system or the classical surgeon-controlled technique. The postoperative leg alignment was analysed on long-leg coronal and lateral X-rays. The mechanical limb axis was significantly better in the navigation-based group. Twenty-three patients (92%) in the computer-assisted group had a postoperative leg axis between 3 degrees varus/valgus deviation, while 19 patients (76%) in the conventional group had a comparable result (p<0.05). Further, significant differences were seen for the coronal orientation of the femoral component. Computer-assisted revision TKA leads to a superior restoration of leg alignment compared with the conventional technique. Particularly the real-time presentation of the actual leg axis and the flexion and extension gaps is useful in revision TKA. Potential benefits in long-term outcome and functional improvement require additional investigation.

Aged↗
PubMed2004

Navigation in total-knee arthroplasty: CT-based implantation compared with the conventional technique.

Background Exact axial limb alignment in total-knee arthroplasty (TKA) is important for a successful outcome. We evaluated the efficiency of computer-assisted implantation in TKA and compared it with the classical surgeon-controlled technique. Patients and methods We implanted 100 TKA using either the computer-assisted technique (50) or the conventional approach (50). There were no significant differences between the groups regarding the preoperative leg deformity. Accuracy of implantation was determined in postoperative long-leg coronal and lateral radiographs. Results A postoperative leg axis between 3 degrees varus and 3 degrees valgus was achieved in 46 patients in the group with computer-assisted implantation and 36 patients in the control group (p=0.01). A significant difference was also seen for the femoral component alignment in frontal plane. No complications influencing the clinical outcome were observed. Interpretation A CT-based navigation system improves the accuracy of TKA, but higher costs and time-consuming planning will mean that its usage is limited to special cases. Additional tools such as ligament balancing, which are presently only available with the CT-free software module, require to be added to the CT-based system.

Adult↗
PubMed2003

Proposal for a sonographic classification of target joints in rheumatoid arthritis.

OBJECTIVE: The purpose of this study was to classify sonographically the joint damage of target joints in patients with rheumatoid arthritis (RA). METHODS: During a 3-year cross-sectional study, standardized arthrosonography of symptomatic target joints was performed in patients with RA. According to those findings, a classification with progressive deterioration of joint alteration in RA was created that grades visible morphological changes of the joint components. Using elbow joints as a subgroup, inter- and intraobserver reliability was calculated. RESULTS: Examined and included in this study were 1211 joints of 425 patients with RA. The mean disease activity score was 5.2 (range 0.75-7.79). Sonographically visible changes could be classified and divided into six stages. A standardized sonographic evaluation system was developed. In reference to the elbow joint, overall percentages for intra- and interobserver reliability of sonography were 90.8% and 88.8%, respectively. CONCLUSION: Sonography is a valuable tool for assessing and classifying joint alteration in RA. Particularly in early stages of joint affection, ultrasound is superior to X-ray in detecting soft tissue changes and minor erosions.

Adult↗
PubMed2003

Sonographic evaluation of the elbow in rheumatoid arthritis: a classification of joint destruction.

The purpose of this study was to evaluate and classify sonographically the joint damage of the elbow in patients with rheumatoid arthritis. Standardized sonography of the elbow joint was performed in patients with rheumatoid arthritis between 1998 and 2002; from 2000 onwards in a controlled and prospective study. A grading of the joint damage was developed, evaluated and compared with the radiographic standard reference films of the Larsen classification. A total of 320 consecutive patients were included in this study; 250 elbows of 125 patients (93 women/32 men) were examined in a prospective way. Mean age was 62.5 years and mean disease duration was 11.9 years. The sonographically visible changes could be divided into six stages. In 24% of the patients graded Larsen 0, sonography detected definite abnormalities classified as stages 1 to 3. Sonography is a valuable tool to assess and classify elbow joint alteration in rheumatoid arthritis. Particularly in early stages of joint affection, ultrasound (US) is superior to X-ray in detecting soft tissue changes and minor erosions.

Adult↗
PubMed2003

Evaluation of differentially expressed genes by a combination of cDNA array and RAP-PCR using the AtlasImage 2.0 software.

Evaluation of genes regulated differentially is essential for the development of therapeutic approaches in multifactorial diseases. To characterize gene expression profiles in multifactorial inflammatory and malignant diseases such as rheumatoid arthritis (RA) or colon adenoma (CA), RNA arbitrarily primed PCR (RAP-PCR) combined with cDNA array hybridization were performed and evaluated using an array-specific software.RNA of synovial fibroblasts from patients with RA and osteoarthritis (OA), and laser microdissected normal and colon adenoma tissue was used. RAP-PCR reactions were hybridized to cDNA array membranes. Arrays were analyzed by phosphor imaging, and the AtlasImage 2.0 software with different normalization settings. The AtlasImage 2.0 software was a useful tool to evaluate differentially expressed genes. However, software settings were needed to be optimized for every experimental approach and should be used without changes for all experiments. To compare RA vs. OA synovial fibroblasts and normal vs. CA expression patterns, global normalization using the sum method is recommended.

Arthritis↗