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PubMed1990

[Total hip prosthesis infected with Salmonella dublin].

In 1983, the bovine-specific Salmonella Dublin was demonstrated in man in Denmark. The organism is frequently isolated from blood but rarely causes gastroenteritis. The frequency of infection following hip replacement is less than 2% with Staphylococcus aureus as the commonest agent while Gram-negative rods are rarer but are considered to be more serious. Infection around a hip replacement frequently implies that the prosthesis must be removed. A case in which a hip replacement was infected with Salmonella Dublin is described here. The patient had looked after infected calves until operation and it is presumed that the prosthesis was infected haematogenically, either primarily or later. The infection was controlled surgically without removal of the prosthesis which was stable. Even although the condition is satisfactory six months after revision, the long-term prognosis is poor.

Ampicillin↗
PubMed1991

[Total hip prosthesis with screw rings. Results over 2 years of a series of 198 consecutive prostheses].

198 screw rings implanted before january 1988, 156 were combined with cementless femoral components, and 42 with cemented femoral components (hybrids). Fifteen cases, which were initially included in the first group, became hybrid at 2 years due to replacement of the femoral component by a cemented stem. 21 screw rings (11 per cent) were revised, and replaced with cemented polyethylene sockets. In 7 cases, acetabular reconstruction was required. Revision was justified by roentgenographic instability in only 6 cases. Four other implants were revised due to persistent postoperative pain, although there was no measurable migration on successive roentgenograms. In the 10 remaining cases, revision was initially justified by the femoral component: screw rings were found to be mobile and were replaced in the same time. Symptoms related to screw rings were easier to identify in hybrid arthroplasties, in which cemented femoral components were usually asymptomatic. Fourty five cases had a complete 2 year follow-up (34 were initially hybrid, 11 became hybrid due to revision of the femoral component). Twenty four patients complained of durable postoperative groin pain. In 18 of these cases, pain completely disappeared within the 18 first months. At 2 years, 28 patients had no pain. In 149 cases with complete 2 year roentgenographic follow-up, 126 implants had never migrated, 6 migrated early but stabilized within the first postoperative year, and 17 showed progressive migration over the first two postoperative years, in which 7 were finally revised. These results are inferior to those reported with cement. Some failures were explained by poor implantation techniques or by wrong indications. Other failures remained unexplained, thus justifying a reduction of their use in our institution.

Adult↗
PubMed1996

Nuclear arthrography: combined scintigraphic and radiographic procedure for diagnosis of total hip prosthesis loosening.

UNLABELLED: Radiographic arthrography and bone scintigraphy are common diagnostic procedures used for evaluating total hip prostheses. In this study, both techniques are combined, and nuclear contrast imaging (nuclear arthrography) is added. The efficacy of the procedures is evaluated. METHODS: After intravenous injection of 99mTc-methylene diphosphonate (MDP), standard radiographic arthrography was performed in 105 patients (107 prostheses). The radiographic contrast medium was mixed with insoluble 111In-colloid (5 MBq/20 ml). After completion of the radiographic arthrography, nuclear arthrography was performed, and multiple-view dualisotope images (111In, 247-keV peak only) were recorded. Images were interpreted by superposition of the 111In image and the corresponding 99mTc-MDP image, the latter serving as a landmark for the position of the prosthesis and osseous structures. Findings at surgery were used as the gold standard. RESULTS: In both cemented and uncemented acetabular and femoral components, nuclear arthrography performed better than or equal to radiographic arthrography (70%-90% and 60%-75%, respectively). Nuclear arthrography had higher diagnostic accuracy than 99mTc-MDP images alone. CONCLUSION: Nuclear arthrography is a sensitive technique for detection of loosening of prostheses, offering added value over radiographic arthrography and bone scanning alone, especially for evaluation of the femoral component. Radiographic arthrography remains necessary not only for adequate deposition of contrast agents but also for detailed evaluation of osseous structures.

Cementation↗
PubMed1992

Nickel-, chrom- and cobalt-concentrations in human tissue and body fluids of hip prosthesis patients.

The world-wide experience with millions of metallic implantations suggests the biocompatibility of modern alloys, commonly made of cobalt, chromium and nickel. There is, however, little information available on the internal metal exposure resulting from implants. In this study we assessed the metal concentrations in body fluids and tissue samples (muscle, bone) of patients who had undergone total hip replacement. Our patients were divided up into two groups. One group had firmly fixed implants two years after surgery. The other group had loose implants of the same Co-Cr-Mo alloy. Urine analyses revealed an increased renal elimination of nickel, chromium and cobalt. Cobalt and nickel exceeded the upper normal value. In serum the concentrations of nickel and chromium were normal or slightly elevated, the cobalt concentrations were significantly elevated. In some cases tissues adjacent to the implant showed extremely high concentrations of chromium and cobalt. This finding was also obtained in tissues that had no direct contact with the arthroplasty. The findings suggest that alloys of prostheses can undergo corrosion and release metal ions.

Aged↗
PubMed2004

Wear evaluation of cobalt-chromium alloy for use in a metal-on-metal hip prosthesis.

Wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure, which has been extensively reported in the last 20 years. Although research continues to attempt to reduce the wear of polyethylene joint-bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of metal-on-metal bearing couples for hip prostheses. Wear testing of total hip replacement systems involving the couple of metal or ceramic heads on polymeric acetabular components has been performed and reported, but, until recently, there has been little data published for pin-on-disk or hip-simulator wear studies involving the combination of a metallic femoral head component with an acetabular cup composed of the same or a dissimilar metal. This study investigated the in vitro wear resistance of two cobalt/chromium/molybdenum alloys, which differed primarily in the carbon content, as potential alloys for use in a metal-on-metal hip-bearing couple. The results of pin-on-disk testing showed that the alloy with the higher (0.25%) carbon content was more wear resistant, and this alloy was therefore chosen for testing in a hip-simulator system, which modeled the loads and motions that might be exerted clinically. Comparison of the results of metal-on-polyethylene samples to metal-on-metal samples showed that the volumetric wear of the metal-on-polyethylene bearing couple after 5,000,000 cycles was 110-180 times that for the metal-bearing couple. Polyethylene and metal particles retrieved from either the lubricant for pin-on-disk testing or hip simulator testing were characterized and compared with particles retrieved from periprosthetic tissues by other researchers, and found to be similar. Based upon the results of this study, metal-on-metal hip prostheses manufactured from the high carbon cobalt/chromium alloy that was investigated hold sufficient promise to justify human clinical trials.

Chromium Alloys↗
PubMed1985

Minneapolis hip prosthesis in severe destructive lesions of the femur.

The use of the Minneapolis prosthesis was abandoned about 1955 by its originators, who had used it without acrylic for uncomplicated fractures of the femoral neck. This is the first report of its use with 'cement' fixation. It has been found to be very useful and reliable for arthroplasty of the hip in 57 patients with carcinomatous or other severe destructive lesions in the trochanteric region of the femur, being more convenient and easier to use than alternative prostheses and especially valuable in metastatic disease. Technical points relating to operative techniques are described, and postoperative Hamilton-Russell traction is recommended.

Adult↗
PubMed2006

Assessments of different kinds of stems by experiments and FEM analysis: appropriate stress distribution on a hip prosthesis.

BACKGROUND: It is now recognized that initial stability is essential for avoidance of thigh pain in hip replacement. The initial stability corresponds to an optimal stress distribution of cementless orthopedic implants. Although the relationship between the contour and stress at the fixation site has been analyzed, guidelines on stem design have not been established. METHODS: Finite element models of three currently-used stems were constructed for a computer simulation. Contact stress at the fixation site of a joint prosthesis was analyzed by an explicit three-dimensional finite element method. The stress immediately after applying load using a film or sensor which can measure contact stress was observed. The situation of the initial fixation about the specific part which becomes important clinically based on the results was clarified. FINDINGS: We introduced fluctuation area as a measure to evaluate the primary fixation of femoral stems. It was found that the stress distribution on the PerFix SV stem fluctuated with a slight disturbance. On the Intra-Medullary Cruciate stem, the high stress areas were distributed on the proximal area and under the pin. The high stress area on the VerSys stem were spread on the medial side. INTERPRETATION: This study highlights the mechanical instability of the fixation site of joint prostheses, and thus suggests that the general idea that unconditionally recommends a larger area for the fixation site of joint prostheses should be revised.

Biomechanical Phenomena↗
PubMed1983

Fatigue properties of implant materials in hip prosthesis form: a standardized test.

The determination of the fatigue properties on small specimens is not accurate. It does not take into account the considerable scatter in fatigue properties which may arise in the implants. Therefore, testing of the properties on the actual implant is needed. The working hypothesis of the present article is that four-point bending fatigue tests allow determination of the fatigue limit of the femoral component material in total hip prostheses. It eliminates the disadvantages of the previously proposed load on head test because (1) the reproducibility of the stress pattern is easy; (2) the fatigue testing is over the whole critical part of the stem; and (3) the stresses do not change during the test. Testing of a series of hip prostheses shows that (1) the measured fatigue limit is typical for the material tested; (2) the location of the fatigue fractures is over the critical medial third of the stem; and (3) the fractographic aspects correspond to those of in vivo failed prostheses. The four-point bending procedure is proposed as a standard method.

Biocompatible Materials↗
PubMed1991

[Conflict between psoas and total hip prosthesis].

This conflict leads to a chronic irritation of the psoas by the antero-medial part of the cup, but it has been poorly described in the past. A study of six patients suffering from this trauma, and who were re-operated revealed that the muscle was worn thin in front of the prominent cup. In the case of 4 of the 6 patients pain had started to occur shortly after total hip replacement. The following symptoms were noted among all 6 patients: pain was suffered during flexion--extension movements--walking up stairs--arising from a chair. Pressure on the medial part of the groin was painful, especially during active elevation of the lower limb. Passive mobility was normal and painless. Psoas bursitis was observed in three cases. The main cause of this conflict is the protrusion of the cup beyond the antero-medial edge of the acetabulum; this protrusion may be either due to a bone graft or a bit of cement, but most often an acetabular insufficiency (congenital dysplasia) favors the formation of this anterior overhang. The spiral cup screwed into the bone can be especially aggressive when it protrudes. Treatment includes the resection of the overhang, but post-operative results will be uncertain unless the resection is really complete. In the case of 4 patients the results of such an intervention were only mild to poor. This problem can be avoided by proper care and preventive measures in the original replacement avoiding all projections beyond the anterior edge of the acetabulum--cup, bone graft, cement, especially if dysplasic.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1998

[Radiologic changes following cement-free implantation of hip prostheses. 5-year follow-up and clinical experience with the cement-free hip prosthesis Autophor-900-S].

PURPOSE: To evaluate early reliable radiographic signs of loosening in cementless total hip arthroplasty compared to clinical follow-up. METHODS: Within a time interval of 5 years 89 patients with 101 hips underwent total hip arthroplasty using the Autophor 900 S-prosthesis. Clinical and radiographic follow-up were first performed retrospectively followed by a prospective investigation. RESULTS: Radiographic evaluation showed prosthesis fixation in 93%. Loosening of the prosthesis was identified in 4 cases of the acetabular component and in 4 cases of the femoral stem. Pain was associated with radiographically detectable loosening of the cementless arthroplastic components in only two cases. CONCLUSION: Within a follow-up period of up to five years, loosening of cementless total hip arthroplasty occurs in about 7%. The most reliable radiographic signs of loosening are complete radiolucent zones wider than 2 mm at the bone-component interface, progressive subsidence, migration, or tilt of the component. Pain and movement disorders are not specific symptoms and do not necessarily indicate a loosening of the prosthesis.

Adult↗
PubMed1995

[10 years follow-up of the M.E. Müller self-locking cemented total hip prosthesis].

PURPOSE OF THE STUDY: This study concerns the analysis 10 years follow-up survival, of the Muller self-locking cemented straight stem, inserted with a cemented polyethylene socket. MATERIAL: 193 Muller self-locking cemented straight stems were inserted by the author between january 82 and March 83. The first part of the study is a survival analysis of the individual components. The second part is a clinical and a radiological evaluation of 93 hips reviewed at 10 to 11 years with the initial components. RESULTS: Using revision of the components as the definition of failure, survival analysis depicted 94.3 per cent survival for the socket (86.5 per cent), and 98.3 per cent for the femur (95 per cent). 7 sockets and 2 stems were revised in 7 patients (one of them is a late infection at 9 years). Up to date this revisions have been successful. 93 patients, 50 females et 43 males, were reviewed, at an average follow-up time of 10.5 years, with the initial components. 70 hips were rated excellent, 12 good, 9 fair and 2 poor. The two poor results presented stiff joints at follow-up. Complete radiographic studies were available for these 93 patients. 38 sockets had no bone-cement radio lucent lines, 52 had limited non progressive radiolucent lines, 3 had a circumferential radiolucent zone around the cup; two of them migrated. The mean polyethylene wear was 1.30 mm (0.4-2.6). On the femur, there was a low incidence of radiolucencies: 9 patients had limited radiolucencies on the AP view, 4 on the lateral view, with no stem settling more than 3 mm. Demarcations occurred predominantly in Gruen zones 5 et 6 with undersized stems placed in valgus. 13 per cent of the femurs presented some degrees of osteolysis with internal defects of the medial cortex, one was extensive. DISCUSSION: The clinical result of the stem was satisfactory but roentgenographic evaluation revealed signs of osteolysis in 13 per cent of the femurs. This mechanism of bone loss has been clearly documented to occur because of accumulated polyethylene wear debris, a factor which also accounts for the high failure rate of the socket. It could be related to the high friction produced by the 32 mm metallic head. Migration of the debris along the medial cortex is probably consecutive to the design of the self locking stem with a lack of cement on the borders. CONCLUSION: The satisfactory long-term results of the cemented straight Muller stem encourage us to continue, but the 32 mm metallic head should be abandoned. We prefer the use of a 32 mm alumina ceramic femoral head combined with the same stem and polyethylene acetabular cup. The study of this next series with the same follow-up is currently being evaluated.

Actuarial Analysis↗
PubMedDate not supplied

[Nerve lesions after hip prosthesis implantation--fate or treatment error?].

INTRODUCTION: Nerve lesions after hip arthroplasty are common complications which may imply the reproach of a treatment mistake. Thus, the decisive question to the expert runs: fate or treatment mistake? METHODS: Retrospective analysis of all cases dealt with at the medical expert commission of the General Medical Council Nordrhein during 1977-1997 in respect of the damage mechanisms and expert judgments. RESULTS: As long as diagnosis and therapy were set on time, nerve lesions after hip arthroplasty due to extension, pressure or placement of the leg were evaluated as fateful (81%). Delayed treatment as well as incorrect operation technique, -indication, or inadequate documentation were judged as a treatment mistake (19%). CONCLUSION: Nerve lesions after hip arthroplasty cannot always be avoided and thus do not directly imply a treatment mistake. Immediate therapy and precise documentation are important to minimize the damage.

Arthroplasty, Replacement, Hip↗
PubMed1988

The personalized hip prosthesis.

The authors discuss the general concept, method of use and first clinical results obtained with a "personalized" femoral component of a hip arthroprosthesis based on the computer-graphic processing of measurements obtained from radiography and CT scan. This prosthesis is considered to be innovative as compared to traditional cementless prostheses.

Computer Graphics↗
PubMed1988

[Prevention of thromboembolism in patients operated on for hip prosthesis].

The latest research into the prevention of peri- and postoperative thromboembolic disease has found orthopaedic surgery patients to be most at risk. As the genesis of deep venous thrombosis (DVT) is due to haemodynamic, hemorheologic and parietal factors, various prophylactic measures have been considered in the past, measures which have not proved able to provide satisfactory protection in orthopaedics. The results obtained with Defibrotide in a random and controlled clinical study versus calcium heparin involving 211 patients of both sexes candidates to receive total hip arthroplasty and presenting at least one major thromboembolic risk factor are reported. The patients were assigned at random to one of the following treatments: 1) Defibrotide at a dose of 400 mg b.i.d. i.v. in 50 ml phleboclysis in 5 minutes (n = 108); 2) calcium heparin at a dose of 5000 IU t.i.d. subcutaneously (n = 103). The treatment began the day before operation and continued on average up to the eighth day for the Defibrotide group. With the control group it continued until discharge (usually on the 15th day) and at home for about three weeks until the completion of the physiotherapy cycle. In the 108 patients treated with Defibrotide only one case of DVT was reported and in none of these patients were symptoms or signs of pulmonary embolism encountered. In the group treated with calcium heparin 2 cases of clinically and radiologically diagnosed pulmonary embolism and 4 cases of DVT were observed. Although the differences were not statistically significant, the tendency favours Defibrotide. Statistically significant (p less than 0.01) was the difference in postoperative bleeding evaluated with particular attention in patients of advanced age. Further, in the Defibrotide group, scarring was considered excellent in 96% of cases while in the heparin group scarring was excellent in 85% (p less than 0.05). To conclude, the sure clinical effectiveness, tolerance, handiness and lack of interference with clotting functions make Defibrotide a really useful drug for the prevention of thromboembolic episodes in patients undergoing major orthopaedic surgery.

Adult↗