Biomedical subjects

G Saxler

Publications and source records attributed to G Saxler.

At least 19 recordsLinked to original sources

PubMed2007

[Endosteal reaction in the region surrounding the stem of a cement-free prosthesis. An early radiological sign of imminent fracture of the femoral shaft?].

Periprosthetic fractures are familiar complications after total hip arthroplasty and have often been reported in the literature. The most frequent localization of such fractures is the middle third of the shaft. In the case described here a minor trauma resulted in a periprosthetic fracture with fracture of the femur and of the femoral component of a Lord prosthesis. A radiograph taken prior to trauma showed an endosteal reaction at the level at which the fracture later occurred. This might have been an indication that the stem of the prosthesis was already broken; had this radiological sign been correctly interpreted, it is possible that the fracture could have been avoided.

Aged↗

PubMed2007

[Rotating platform spinout in LCS knee arthroplasty].

In knee arthroplasty, a lax flexion gap may cause flexion instability. Subsequently, the operated knee may subluxate or dislocate. We report on a case of recurrent subluxations with malrotation of the rotating platform (spinout) after primary LCS total knee arthroplasty. Potential causes for spinout, therapy procedures, and consequences for the primary surgical technique are discussed. In the LCS rotating platform knee arthroplasty, the flexion gap must not be laxer than the extension gap. In such an instance, we recommend a higher rotating platform and a more proximal distal transverse femoral osteotomy.

Aged↗

PubMed2007

[Structural femoral head allografts in revision surgery of loosened acetabular cups].

BACKGROUND: Treatment of acetabular bone defects presents a great challenge in revision total hip arthroplasty (THA). Many methods of acetabular reconstruction have been described. The purpose of this study was to evaluate the midterm results of structural femoral head allografts for acetabular reconstruction. METHODS: Thirty-six patients (33 females and 3 males) with acetabular defects ranging from type 2C to type 3B according to Paprosky's classification were included in the study. In all cases acetabular defects were closed using allografts from femoral heads. In 13 cases an uncemented press-fit cup, in 17 cases a cemented polyethylene socket, and in 6 cases a Burch-Schneider antiprotrusion cage was implanted. The mean follow-up period was 84.2 months (range: 5-147). RESULTS: Four acetabular components failed. All 36 grafts were osseointegrated radiographically and formed a mechanically stable construction. The mean Harris Hip Score at the most recent follow-up was 79.8 points. The distance from the obturator line to the prosthesis head center was 3.73 cm (1.17-5.80 cm) preoperatively and 2.79 cm (0.85-4.8 cm) postoperatively (p<0.05). The distance from the teardrop figure to the prosthesis head center was 3.02 cm (1.0-5.8 cm) preoperatively and 3.25 cm (1.6-4.8 cm) postoperatively (p<0.001). CONCLUSIONS: Closure of acetabular defects of types 2C to 3B according to Paprosky's classification can be satisfactorily accomplished using femoral head allografts. These allografts may facilitate future revision surgery. Femoral heads are readily available due to widespread primary total hip replacement surgery. However, the use of structural femoral head allografts for acetabular reconstruction is cost intensive. Individual patient-related aspects, such as the function of revision arthroplasty, have to be considered when planning revision arthroplasty using femoral head allografts.

Acetabulum↗

PubMed2007

[Arthroscopy-assisted glenohumeral arthrodesis: a case of uncontrollable shoulder instability].

The promising option of arthroscopy-assisted glenohumeral arthrodesis to treat shoulder instability is presented. Compared with open arthrodesis of the shoulder, especially the cosmetic result of this procedure is better. Clinical follow-up revealed that in addition to pain reduction there was an improvement in the shoulder function as assessed according to the Constant and Murley scores. Evaluation of the DASH questionnaire and the Sf-36 health questionnaire clearly showed the improved function of the arm as well as the positive effect on the patients' general state of health.

Adult↗

PubMed2006

Reinforcement of deficient femur with inlay strut grafts in revision hip arthroplasty: a small series.

Failure of the femoral component due to severe loss of femoral bone is an important long-term complication of total hip arthroplasty. We treated four patients with a type IV femoral defect (Paprosky classification) because of aseptic and septic loosening. To enhance bone stock and create a stable prosthetic reconstruction we used femoral allografts as inlay strut grafts alone or combined with onlay strut grafts and impaction grafting. At a mean follow-up of 11 years all four patients presented good or excellent results with Harris Hip Score between 86 and 95 points. Radiologically, no migration of the stems were found and the struts showed signs of incorporation. Inlay strut grafts are a reliable method for bone reconstruction of deficient femoral bone stock in failed total hip replacement.

Aged↗

PubMed2005

Limited range of motion caused by heterotopic ossifications in primary total knee arthroplasty: a retrospective study of 27/191 cases.

INTRODUCTION: Heterotopic ossification (HO) following primary total knee arthroplasty is a rare complication and may be symptomatic if massive enough. Especially the range of motion (ROM) is essential for the function and durability of the implant. The aim of the study was to evaluate the influence of HO on ROM using clinical and radiological parameters. MATERIALS AND METHODS: We reviewed 191 primary total knee arthroplasties according to the clinical preoperative and postoperative parameters of the Knee Society Score with special interest paid to the ROM. Standardized radiographs were taken at three levels and the implant position compared. The patients were divided into group 1 (with HO) and group 2 (without HO). The clinical and radiological parameters were compared. RESULTS: We found an incidence of HO in 14.1% (n = 27). Group 1 showed a decreased ROM postoperatively (p = 0.003) and worse flexion contracture (p = 0.04) compared with group 2. The evaluated radiological parameters showed no significant difference between the two groups. CONCLUSION: We found a significant limitation of ROM because of HO in our study. We found no correlation between HO and component alignment or component position. Local irritation has to be considered the main reason for limited ROM.

Adult↗

PubMed2005

[Spinal manipulative therapy and cervical artery dissections].

Severe complications after cervical spine manipulation are rare. As experts for medical treatment errors, we received between July 2002 and February 2004 cases with serious complications in the central nervous system after manipulation. 5 vertebral artery dissections with subsequent brain infarction were registered. In all cases, the patients showed complete persisting remission of symptoms. In addition, a kinematic estimation model was developed to study the possible causes of vertebral artery damage. We were able to demonstrate that material extension is dependent on cervical rotation and the "free length" of the vertebral artery in the upper cervical spine.

Adult↗

PubMed2005

[Reconstruction of the tibial diaphysis with transfer of the tibial head onto the proximal fibula. Follow-up after 63 years].

Osteoarthritis of the knee is often diagnosed in the orthopedic trauma practice. One major cause is axial deformity with overload. In the case presented here osteomyelitis of the tibial diaphysis developed in childhood. Surgical treatment consisted of resection of the middle tibial third and transferring the tibial head onto the proximal fibula. In this way it was possible to eradicate the osteomyelitis of the lower leg and to achieve osseous consolidation between the tibia and fibula. Despite the significant shortening of the lower limb and the varus axial deformity, the knee joint function was satisfactory in the subsequent development. After a long interval without symptoms the patient developed a medially accentuated osteoarthritis of the knee.

Aged↗

PubMed2005

[A comparison of the antiresorptive effects of bisphosphonates and statins on polyethylene particle-induced osteolysis].

An ongoing unraveling of the molecular mechanisms in aseptic loosening of hip arthroplasty has opened up novel potential pharmacological interventions. In this study the antiresorptive effects of the bisphosphonate zoledronate and the statin simvastatin on ultra high molecular weighted polyethylene (UHMWPE) particle-induced osteolysis were compared. Two previous studies of our group based on the murine calvarial model of UHWMPE particle-induced osteolysis were pooled to form four study groups. Animals in group I (n=14) underwent sham surgery only. In groups II (n=14), III (n=7) and IV (n=7) UHMWPE particles were implanted on the calvariae. Animals in groups III and IV were additionally treated with zoledronate (single 25 microg/kg s.c. injection) and simvastatin (120 mg/day p.o. for 14 days), respectively. After two weeks, calvaria were processed for undecalcified histomorphometry. Bone resorption was measured using Giemsa staining. Osteoclast numbers were determined using TRAP-staining. UHMWPE particle implantation resulted in a grossly pronounced osteolytic activity with significantly increased values of bone resorption (p < 0.001) and osteoclast numbers (p < 0.001). Additional treatment with zoledronate or simvastatin counteracted the particle-induced effects. A comparison of the two medical treatments revealed no statistically significant differences in bone resorption (p = 0.63) and osteoclast numbers (p = 0.41). A single dose of the bisphosphonate zoledronate decreased UHMWPE particle-induced osteolysis in a murine calvarial model as effectively as a daily treatment with simvastin. Both drug groups may have a preventive and therapeutic role as antiresorptive agents in wear particle-induced bone resorption following total joint replacement.

Animals↗

PubMed2004

The accuracy of free-hand cup positioning--a CT based measurement of cup placement in 105 total hip arthroplasties.

We studied 105 patients who received a total hip arthroplasty between June 1985 and August 2001 using freehand positioning of the acetabular cup. Using pelvic CT scan and the hip-plan module of SurgiGATE-System (Medivision, Oberdorf, Switzerland), we measured the angles of inclination and anteversion of the cup. Mean inclination angle was 45.8 degrees +/-10.1 degrees (range: 23.0-71.5 degrees ) and mean anteversion angle was 27.3 degrees +/-15.0 degrees (range: -23.5 degrees to 59.0 degrees ). We compared the results to the "safe" position as defined by Lewinnek et al. and found that only 27/105 cups were implanted within the limits of the safe position. We conclude that a safe position as defined by Lewinnek et al. [13] was only achieved in a minority of the cups that were implanted freehand.

Adult↗

PubMed2004

[AMC unicondylar prosthesis].

Since its introduction in the 1970s, unicompartmental knee arthroplasty (UKA) has become a standardized routine technique. Increasing experience in determining the indication for UKA and improvements in design and materials of the prosthesis have led to better results. The AMC UKA has an unconstrained mobile bearing with congruent area contact from 0 degrees to 30 degrees of flexion. The principle is that a polyethylene mobile bearing, concavely spherical above and flat below, can maintain perfect congruity between the spherical metal femoral condyle and the flat metal tibial plateau. This ensures complete freedom to rotate and slide upon one other with physiologic kinematic and low intrinsic stability. The low contact stress results in reduced polyethylene wear. The 361 AMC UKA replacements of the current study showed safe anchorage of the prosthesis and good durability of the mobile bearings. The clinical results of the investigated patients demonstrate that the AMC UKA is a successful concept. The comparison of 30 minimally invasive UKA with 30 conventional UKA and 30 total knee replacements shows an advantage of the minimally invasive technique with regard to reduced rehabilitation time. The accuracy of implantation was comparable between the conventional and the minimally invasive techniques.

Aged↗

PubMed2004

[Titanium as an implant material for rods of transpedicular instrumentation of the lumbar spine].

BACKGROUND AND AIM: Titanium alloys are increasingly being used as an implant material in orthopaedics and for spinal instrumentation. In this study a metallographic analysis and mechanical testing were performed to evaluate the resistance of rods of Ti-A16-V4 in particular to tensile forces. METHOD: The surface texture of unprepared Ti-A16-V4 and a rod of the same material for spinal instrumentation were evaluated in a metallographic analysis using light microscopy and electron microscopy. Tensile strength measurements were performed on 2 rods, and the strength of the connection between rod and pedicle screws was tested in 9 cases. An electron microscopic analysis of surface changes of the connections between rod and pedicle screws after loading was performed. RESULTS: The titanium alloy Ti-A16-V4 has a mill-annealed appearance, which has a high resistance to tearing under stress. Titanium rods show high tensile strength before failure under loading. The connection between rod and pedicle screws also as high resistance to tensile loads (> 27 kN) with only little deformation of the connecting surface and no tearing. CONCLUSION: The titanium alloy Ti-A16-V4 is an appropriate material for dorsal spinal instrumentation rods because of its low weight, high biocompability and high tensile strength.

Alloys↗

PubMedDate not supplied

[Extensive spinal epidural hematoma--an uncommon entity following cervical chiropractic manipulation].

INTRODUCTION: Spinal epidural hematoma is a rare complication after chiropractic manipulation. In the literature, only three cases have been reported, which all necessitated surgical treatment. CASE: A 27-year-old woman was treated with cervical chiropractic manipulation (C5/6) and facet joint infiltration. 10 minutes later the patient presented signs of intracranial pressure with nausea, vertigo, headache and vomiting. The magnetic resonance imaging of the spine demonstrated an epidural hematoma extending from the cervical to the sacral spine. As the patient had no sensible or motor deficits and recovered quickly, surgical treatment was not necessary. A few days later the patient had a complete persisting remission of symptoms. CONCLUSION: If neurological deficits occur after chiropractic manipulation, a spinal epidural hematoma should be considered to provide adequate therapy without delay. The current case report shows an unusual expansion of the hematoma which has not described so far after chiropractic manipulation. But, in contrast to the three cases reported before, a surgical intervention was not necessary.

Adult↗

PubMedDate not supplied

[Size and shape of commercially available polyethylene particles for in-vitro and in-vivo-experiments].

AIM: The longevity of total hip arthroplasty is sometimes limited by osteolysis and aseptic loosening. Aseptic loosening may be caused by the biologic reaction to polyethylene wear particles. Particles of less than 1 micro m diameter are of particular importance. These particles are not easily available for experimental use. METHOD: We performed a morphologic analysis of commercially available, very small polyethylene particles (Ceridust(R)) in order to determine the specific size distribution. We measured 1 978 particles. Size analysis was performed using an electron microscope. Particle size was described as the equivalent circle diameter (ECD). Particle morphology was described as feret ratio. In addition, Ceridust(R) particles were compared to different particles stemming from a hip simulator experiment. RESULTS: More than 35 % of the particles were less than 1 micro m in size. The particle size was 1.75 micro m +/- 1.43 micro m (median 1.42 micro m). The minimum was 0.06 micro m, the maximum was 11.06 micro m. The feret ratio was 0.58 +/- 0.17 (median 0.63). The minimum was 0.07, the maximum was 0.93. The majority of Ceridust(R) particles had a rough surface. Compared to polyethylene particles stemming from a hip simulator experiment, Ceridust(R) particles had a rougher surface, were less longitudinal, and had a more even size distribution. CONCLUSIONS: The pure, commercially available polyethylene particles analyzed here are suitable for in vitro and in vivo experiments due to their easy availability, minor costs, and large fraction of very small particles.

Biocompatible Materials↗

PubMedDate not supplied

[Cup placement in hip replacement surgery -- A comparison of free-hand and computer assisted cup placement in total hip arthroplasty -- a multi-center study].

AIM: The purpose of the current study was to determine the accuracy of free hand and computer-assisted (CAS) cup placement. MATERIAL AND METHODS: Between June 1985 and August 2001, 105 free-hand and from March to November 1999 80 total hip arthroplasties under computer assistance were implanted in the above mentioned centers. To determine the accuracy of the cups, the inclination and anteversion angles were measured. In all cases the cup position was measured with a CT-investigation of the pelvis. Statistical analysis was performed with the F-test. RESULTS: With regard to the inclination and anteversion angles the variability of the cup position was significantly higher in the group of free hand implanted cups. In the CAS group we could not find any "extreme" positions. CONCLUSION: Using computer-assisted surgery a significantly higher reproducible cup position can be obtained. Long time survey may present a lowering of the rate of early and late complications caused by better prostheses alignment in the follow up.

Adult↗

PubMedDate not supplied

[Revision of failed acetabular cups with extensive structural allografts].

AIM: Structural allografts are used with encouraging results for revision of failed total hip arthroplasty and in the surgery of bone tumours. The aim of the present study is to describe the clinical and radiological results achieved with structural allografts in revision of a total hip arthroplasty. MATERIAL AND METHODS: 15 patients (12 female and 3 male patients) were revised with an acetabular defect situation of type 3 A or 3 B according to the Paprosky classification. Five fresh-frozen acetabula, nine distal femora and one proximal tibia were used for acetabular reconstruction. The rigid graft fixation was performed with 2 > or = AO screws. In one case a cemented acetabular ring was implanted, four cementless cups and ten cemented polyethylene acetabular components were used. The mean follow-up was 7.9 years (1.6-11.0 years). RESULTS: A stable osseointegration of fifteen transplanted structural allografts was achieved in thirteen cases. Two allografts (one aseptic loosening, one deep infection) failed to osseointegrate. In one case the migration of a cementless cup was registered. Revision surgery of this female patient was performed successfully with a cemented reconstruction ring. The mean Harris hip score at the latest follow-up was 81.4 points (70-99 points). CONCLUSION: For reconstruction of acetabular bone stock and restoration of the bone anatomy structural allografts can be recommended. The use of cementless cups in combination with structural grafts is to be evaluated as critical.

Acetabulum↗

PubMedDate not supplied

[Follow-up study after dynamic and static stabilisation of the lumbar spine].

INTRODUCTION: The clinical indication for graf's ligamentoplasty and dorsoventral fusion may be described as the "lumbar instability syndrome". A follow-up comparison between Graf's ligamentoplasty and instrumental dorsoventral fusion in a consecutive series of 52 patients was performed. METHODS: 52 patients operated on for low back pain were recalled for a clinical and radiological review (at mean 79 months postoperatively). 26 patients underwent Graf' ligamentoplasty and 26 patients underwent dorsoventral fusion. We evaluated the surgical results and measured an objective outcome using the Oswestry Score, Low Back Outcome Score (LBOS) and Visual Analogue Scale (VAS). For radiological evaluation the Mimura and the Pathria Scores were used. RESULTS: There was no statistically significant difference between the two groups, when measured by the Oswestry Score, LBOS and VAS at the latest follow-up. The difference between the preoperative and actual VAS in each group was statistically significant (p < 0.001). Furthermore, there was no provable preoperative parameter in favour of either one of these therapies. CONCLUSION: Both methods for stabilisation methods of the lumbar spine had a comparable clinical outcome.

Adult↗

PubMedDate not supplied

[Localization of the neurokinin 1 receptor in hip joints of patients with painful osteoarthritis].

INTRODUCTION: Recent studies on osteoarthritis have focused on nociceptive substance P (SP) containing afferent nerve fibres. The effects of SP are known to be mainly mediated by the tachykinin receptor neurokinin 1 (NK1-R). AIM: The aim of the present study was to demonstrate the NK1-R in human joint tissues. METHODS: The hip joint capsule of three patients with painful hip osteoarthritis (Group 1), three patients with femoral neck fracture showing no cartilage destruction (Group 2, controls) and the soft tissue of the fossa acetabuli of Group 1 were resected during hip arthroplasty implantation. The tissue samples were cut into small blocks and immersion-fixed in Zamboni's fixative. The specimens were frozen, cut into 50 microm sections and immunostained using a standard immunohistochemical staining protocol. RESULTS: In Groups 1 and 2 the NK1-receptor was localised in the wall of venous vessels, on Schwann cells of nerve bundles and on nerve fibres. In the osteoarthritis group the staining pattern was similar but the number of NK1-bearing cell structures seemed to be enhanced. CONCLUSIONS: The present study provides the first evidence of NK1-R in the human hip joint. In patients with painful osteoarthritis the density of NK1-R-positive cell structures seemed to be increased. The localisation of the NK1 receptor on different cell types suggests multiple effects of SP in normal and osteoarthritic joints.

Acetabulum↗