Biomedical subjects

A Schuh

Publications and source records attributed to A Schuh.

At least 37 records · Page 2Linked to original sources

PubMed2004

[Bilateral localized osteolysis after cemented total hip replacement].

The incidence of focal progressive osteolysis after THR is about 8% and 56%. Most often osteolysis is correlated with macrophage-induced osteoclastic bone resorption as a sequel of inflammatory reaction to wear particles. Recently these findings were published in respect to allergic reactions to implants, their alloying constituents, or bone cement. We report about a patient who developed bilateral localized osteolysis just below the cement mantle 5 years after cemented THR with a Müller straight stem. In the middle of the osteolysis small fragments of bone cement could be detected. Epicutaneous testing showed no reaction against cobalt, chromium, or nickel. Further epicutaneous testing in respect to ingredients of the bone cement were refused by the patient. Histological examination revealed a histiocytic reaction to wear particles and surrounding giant cells. To our knowledge, this is the first case of bilateral localized osteolysis after cemented total hip replacement. Taking all results of the current case into account, it is still unclear if a lymphocytic allergic contact reaction did contribute to the sequel of this case. Reports of immunologically induced incompatibility to components of bone cement, the development of extended testing procedures, and further scientific research should contribute to optimizing the care of patients.

Bone Cements↗

PubMed2004

[Delayed paresis of the femoral nerve after total hip arthroplasty associated with hereditary neuropathy with liability to pressure palsies (HNPP)].

Delayed lesions of the femoral or sciatic nerve are a rare complication after total hip arthroplasty. Several cases in association with cement edges, scar tissue, broken cerclages, deep hematoma, or reinforcement rings have been published. We report about a 62-year-old female who developed a pure motor paresis of the quadriceps muscle 2 weeks after total hip arthroplasty. After electrophysiological evaluation had revealed an isolated femoral nerve lesion, revision of the femoral nerve was performed. During operative revision no pathologic findings could be seen. One week later the patient developed paralysis of the left wrist and finger extensors after using crutches. Electrophysiological evaluation revealed several nerve conduction blocks in physiological entrapments and the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) was established. Hereditary neuropathy with liability to pressure palsies (HNPP) is a rare disease with increased vulnerability of the peripheral nerve system with mostly reversible sensorimotor deficits. It should be taken into consideration in cases of atypical findings of compression syndromes of peripheral nerves or delayed neuropathy, e. g., after total hip arthroplasty.

Arthroplasty, Replacement, Hip↗

PubMed2004

[Surface characterization of Al2O3-blasted titanium implants in total hip arthroplasty].

INTRODUCTION: Shot peening and grit blasting techniques are used in several surface modifications for producing hip endoprostheses. Corund blasting techniques using highly pure Al2O3 particles to create a rough surface of titanium implants in cementless total hip arthroplasty achieve better osteointegration. An increasing number of publications in maxillofacial surgery and orthopedic surgery show that there is a significant contamination on corund-blasted surfaces. The latest research studies reported an effect of contaminant particles on early failure of endoprostheses associated with third body wear. The aim of our work was to evaluate the amount and particle size of Al2O3 on the implant surface. MATERIAL AND METHOD: The surface of four different geometries (five parts each, ARR titanium acetabular reinforcement ring, anisotropic Vektor cup, Vektor titanium stem and modular MRP Titan stem) were analyzed with respect to Al2O3 particles. Grit blasting was performed with Al2O3 particles, Alodur SWSK, Fa. Treibacher. Field emission scanning electron microscopy (LEO 1525) was used for the detection of the Al2O3 particles at the implant surface with a backscattered electron detector. The particle size distribution as well as the average area of the covered surface was calculated with image analyzing software (analySIS, Soft Imaging System GmbH). RESULTS: The surface of the anisotropic Vektor cup was contaminated at an average of 41.7+/-4.9%, the Vektor titanium stem at an average of 33.3+/-4.7%, the (MRP) Titan stem at an average of 30.6+/-4.2%, and the ARR titanium acetabular reinforcement ring at an average of 23.2+/-1.6 with Al2O3 particles over the whole surface orientated to the bone. DISCUSSION: The results of this study clearly show that there is contamination of rough titanium surfaces with Al2O3 particles at an unexpectedly high percentage. With respect to third body wear in total hip arthroplasty, further studies are necessary to minimize contamination of roughened surfaces and maintain sufficient roughness for osteointegration.

Aluminum Oxide↗

PubMed2004

[Titanium deposits on the ceramic heads of dislocated total hip replacements].

INTRODUCTION: In cases of revision total hip replacement (THR) having acetabular titanium components with dislocations in the past, metallic deposits are frequently found on the ceramic heads. The aim of this study was to determine whether the metallic deposits increase surface roughness in definite areas. MATERIALS AND METHODS: Ten ceramic heads of revised THR which showed metallic deposits were investigated. The patients suffered from one to six dislocations. The prosthesis lifetime ranged from 2 weeks to 12 years. Surface structure was investigated in a scanning electron microscope (LEO 1525), and the metallic deposits characterised by means of energy dispersive x-ray analysis (EDX). RESULTS: In the area of the metallic deposits, titanium was detected by EDX. Edges with a significant increase in surface roughness were observed, partially accompanied by damage to the surface structure and loosening of Al(2)O(3) particles. DISCUSSION: Titanium deposits increase surface roughness in definite areas, which probably causes wear to the ceramic-ceramic or ceramic-polyethylene articulations due to different roughness values and surface properties. Further investigations are necessary in order to determine the importance of these findings with respect to wear and loosening of total hip arthroplasty.

Aged↗

PubMed2004

[Arthrodesis of the hip and its conversion].

Arthrodesis of the hip used to be an important means of treating painful and damaged hips. Increasing experiences in total hip replacement have led to restrictive indications for arthrodesis and to more and more total hip arthroplasty. Hip arthrodesis has limited indications today. It remains the treatment of choice in deteriorated, painful hip joints, especially in the case of contraindications and severe muscular deficits. The best position of the fused hip is 10 to 25 degrees flexion, 0 to 15 degrees external rotation, 0 to 10 degrees abduction or 0 to 6 degrees adduction. The aim of the operation is a stable osteosynthesis which allows early mobilisation of the patient. Disturbances in walking patterns, mechanical overloading of neighbouring joints, such as the lumbar spine, ipsilateral knee or contralateral hip, often support a conversion from arthrodesis to total hip arthroplasty. The aim of the primary operation, therefore, is the preservation of the stabilizing pelvitrochanteric muscles and their insertions.

Arthrodesis↗

PubMed2004

[Long-term results of surgical therapy of epicondylitis humeri radialis using the technique described by Mittelmeier].

INTRODUCTION: Tennis elbow is one of the most common stress induced pathological findings in patients consulting an orthopaedic surgeon. In refractory cases operation is indicated after conservative treatment. Several operative techniques have been published. We prefer the technique described by Mittelmeier. Aim of this study is to show long- term results of operative therapy of the tennis elbow using this technique. PATIENTS AND METHOD: Between 1.1.1980 and 31.12.1992 we performed 115 outpatient operations for epicondylitis humeri radialis using the technique described by Mittelmeier. After a mean follow-up of 15,3 years we could examine 98 patients according to the score of Roles and Maudsley. RESULTS: We found excellent results in 47 %, good results in 43 % and fair results in 10 % of the evaluated cases. All patients had a benefit concerning the operation. There was one infection as a serious complication which led to revision. CONCLUSION: In epicondylitis humeri radialis surgical therapy according to Mittelmeier leads to good long-term results and can be recommended for persistent radial epicondylitis.

Adult↗

PubMed2004

[Femoral nerve palsy due to excessive granuloma in aseptic cup loosening in cementless total hip arthroplasty].

AIM: Femoral nerve palsy after total hip arthroplasty can result from several causes. Delayed neuropathies of the femoral nerve because of excessive granuloma in loosened implants are a rare condition. CASE REPORT: We report the case of delayed neuropathy of the femoral nerve after cementless total hip arthroplasty because of aseptic loosening of the cup. Electrophysiologic evaluation revealed a severe lesion of the femoral nerve with sensomotoric deficits. An abdominopelvic computed tomography (CT) scan revealed an excessive granuloma with a large intrapelvic portion. After revision of the loosened acetabular component and the femoral nerve and removal of the granuloma the neurologic symptoms improved. CONCLUSION: Regular (1-2 years) clinical and radiological follow-ups are requested after total hip arthroplasty to prevent excessive loosening of implants, excessive granuloma and severe sequelae like nerve damage.

Arthroplasty, Replacement, Hip↗

PubMed2004

[Surface characterisation of shot peened implants with glas beads in total hip arthroplasty].

UNLABELLED: Alumina-blasting is used to create a rougher surface of Titanium implants in cementless total hip arthroplasty to achieve a better bony ingrowth. An increasing number of publications in maxillofacial surgery and orthopaedic surgery show that there is a significant contamination in Alumina blasted surfaces. Latest research published an effect of contaminant particles on early loosening of endoprostheses associated with third body wear. Due to our knowledge no previous study analysed surface contamination of hip endoprostheses with glass beads. Aim of our work was to evaluate the percentage of contaminated surface of hip endoprostheses with glass beads. MATERIAL AND METHOD: The surface of 5 Ti-VPS sprayed Phoenix cups and 5 morse-taper-junctions of the MRP-Titan revision stem (Peter Brehm, Chirurgie Mechanik, Weisendorf) were analysed with respect to glass particles. Shot peening was performed with glass beads "BALLOTINI" MGL, Fa. Würth Strahlmittel. A field emission scanning electron microscopy (LEO 1525) was used for the detection of the glass-particles on the implant surface with a backscattered electron detector. The particle covering position was calculated by means of an imaging analyze software (analySIS, Soft Imaging System GmbH). RESULTS: The surface of the Ti-VPS sprayed Phoenix cups showed a contaminated area at a mean of 9.2 +/- 1.3 %, morse-taper-junctions of the MRP-Titan stem at a mean of 9.6 +/- 2.1 % with glass particle contact. DISCUSSION: The results of this study clearly show that there is a contamination of shot pinned Titanium surfaces with glass particles in a significant percentage. With respect to third body wear in total hip arthroplasty further studies are necessary to minimize contamination.

Equipment Contamination↗

PubMed2004

[Results of fixation of osteochondral lesions of the talus using K-wires].

INTRODUCTION: Etiology of osteochondral lesions of the talus remains uncertain, a myriad of treatment options exists. The purpose of this study is to evaluate the clinical and radiological results of fixation of osteochondral lesions of the talus using K-wires. An unstable osteochondral fragment or osteosclerotic changes in the bed of the talus were regarded as indications for the procedure. PATIENTS AND METHOD: We report a retrospective study of 20 patients who underwent fixation of osteochondritis dissecans of the talus between 1.1.1995 and 31.12.2000. There were 14 men and 6 women. The average age was 18 years (range, 11 to 52 years). The average duration of symptoms prior to surgery was 30 weeks (range, 8 to 100 weeks). RESULTS: The average duration of follow-up was 46 months (range, 18 to 93 months). The overall clinical result was rated good in 4 cases and excellent in 16 cases according to the Ogilvie-Harris score. There were no surgical complications. All osteochondral lesions healed. CONCLUSION: Using K-wires for fixation of osteochondral lesions of the talus repair of the articular surface and stability of the lesion can be achieved even in unstable chronic lesions.

Adolescent↗

PubMed2004

[The modular hip revision stem made of titanium alloy--influence and optimisation of bending stiffness].

UNLABELLED: The MRP-Titan Revision stem has proved to be a highly successful implant system for revision arthroplasty of the hip. Good and excellent clinical and radiological results with spontaneous filling of bony defects have been reported, The observation of atrophy of the proximal femur associated with stem diameters > 17mm prompted us to examine the bending stiffness of stems of various diameters. To determine their static bending characteristics, the stems were tested under axial pressure loads in accordance with Euler's buckling case. Dynamic tests were performed with the mono-axial servohydraulic test equipment MTS 810. From a stem diameter of 18 mm upwards, deflection of the stem under loading decreased disproportionately, in direct correlation with the stem stiffness. By optimising the geometry and varying the alloy it is possible to obtain a constant ISD factor for the modular MRP-Titan revision stem CONCLUSION: The MRP-Titan revision stem is a reliable implant system for revision arthroplasty of the hip. Clinical findings of atrophy of the proximal femur associated with stem diameters > 17 mm was found to be correlated with a disproportionate increase in bending stiffness. The aim of further developments will be to reduce the stiffness of larger-diameter stems by making changes to the design and/or to the alloy (Ti15Mo, Ti13Nb13Zr, Ti12Mo6Zr2Fe2).

Compressive Strength↗

PubMed2003