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Biomedical subjects

B M Wroblewski

Publications and source records attributed to B M Wroblewski.

At least 127 records · Page 7Linked to original sources
PubMed1989

[Loosening of hip prostheses].

Charnley's low-friction total hip prosthesis is now considered one of the most effective treatment methods available in the discipline of orthopaedic medicine; it must be mentioned that it is also one of the most demanding. The treatment does not end with implantation of the total hip prosthesis: this step is only the beginning of a long period of meticulous patient care. This requires regular monitoring of the clinical and roentgenological findings over many years. The results of the initial implantation depend very heavily both on a correct surgical technique and a reliable asepsis. The sterile "greenhouse", with air changes at least 300 times per hour, has proved impressively worthwhile. The proximal support of the stem is an important factor in the durability of the femoral component. The durability of the socket component is obviously influenced more by attrition of the polyethylene than by the method of socket fixation. The controversy about whether fixation with or without cement is better is relatively unimportant. If a prosthesis does loosen, replacement must be considered under the essential aspects of subjective symptoms and progressive bone resorption. Delay in replacement of a prosthesis when this is indicated can jeopardize the ultimate result of treatment because of the progressive bone loss.

Hip Prosthesis↗
PubMed1988

Long-term results of hip arthroplasty for failure of previous surgery.

We report a retrospective review of 127 low friction arthroplasties carried out for the failure of a previous hip operation. After an average follow-up of 10.4 years, 20% of cases required further revision, over half of them for deep infection. We estimated from the radiographic appearances that eventual failure by loosening was probable in 58% on the femoral side and 56% on the acetabular side of the arthroplasties.

Adolescent↗
PubMed1988

Socket design and cement pressurisation in the Charnley low-friction arthroplasty.

An experimental evaluation was made of the efficacy of an unflanged cup, an ogee-flanged cup and the Exeter pressuriser in the pressurisation of acetabular cement. Only a very modest injection pressure could be generated through an unflanged socket and even this was readily lost as the socket "bottomed out". The ogee-flanged socket gave a consistently high injection pressure which could be maintained throughout the process of polymerisation. The Exeter pressuriser gave marginally better results. Of the two cements tested, Palacos with gentamicin showed better intrusion than CMW Type 1 cement, but it also allowed greater extrusion once pressure was released. The importance of maintaining a continuous pressure on the cement throughout polymerisation is emphasised.

Bone Cements↗
PubMed1988

Mechanical loosening of the stem in Charnley arthroplasties. Identification of the "at risk" factors.

A retrospective review of 72 cases of Charnley low friction arthroplasty revised for stem loosening, has identified a number of "at risk" factors. These were: previous hip surgery and, in radiographs taken at one year, demarcation of the distal cement and fracture of the cement near the tip of the stem. Separation of the back of the stem from the cement, as an isolated feature, was not considered significant. Endosteal cavitation of the femoral shaft, rare in the first year, indicated loosening of some duration. Patients whose radiographs show the "at risk" changes, should be followed-up indefinitely in order to plan timely revision and avoid gross loss of the femoral bone stock.

Adult↗
PubMed1988

Wear and loosening of the socket in the Charnley low-friction arthroplasty.

In the Charnley low-friction arthroplasty, wear of the HDP socket and the dimensional changes resulting from it are more important than the tissue response to wear debris. Study of wear and the related mechanical factors is likely to be more rewarding than the search for alternative methods of fixation.

Acetabulum↗
PubMed1988

The correlation between the roentgenographic appearance and operative findings at the bone-cement junction of the socket in Charnley low friction arthroplasties.

In a series of 200 Charnley low friction arthroplasties revised for various reasons, the preoperative anteroposterior roentgenograms were categorized in terms of demarcation at the bone-cement interface of the socket and compared with the operative findings of movement at the bone-cement junction. All sockets showing no demarcation were found to be fixed soundly. Seven percent of the sockets showing demarcation of the outer one-third only were loose, and when two-thirds of the sockets were demarcated, 71% were loose. Ninety-four percent of the sockets with complete demarcation and all sockets that had migrated were found to be loose at revision. There is a definite correlation between roentgenographic demarcation and socket loosening. The more extensive the demarcation, the more likely it is that the socket is loose. Radiographic demarcation of the cemented socket is a prognostic sign for eventual failure.

Adult↗
PubMed1987

External wear of the polyethylene socket in cemented total hip arthroplasty.

We examined 59 cemented high density polyethylene sockets removed at revision hip arthroplasty. Of these 19 showed areas of wear between the outside of the socket and the acetabular bone. This was associated with lack of acrylic cement in those areas and was also related to the depth of the wear on the articulating surface of the socket. It is suggested that, in some cases, changes at the bone-cement junction are secondary to socket loosening and abrasion against the bone of the acetabulum, rather than to particles migrating from the metal-polyethylene interface. It is therefore important that impingement of the neck of the femoral stem on the edge of the cup be avoided and that, when the socket is inserted, it is not in direct contact with the bone.

Acetabulum↗
PubMed1987

Deep infection in Charnley low-friction arthroplasty. Comparison of plain and gentamicin-loaded cement.

A retrospective review of 1542 Charnley low-friction arthroplasties was carried out to compare the incidence of deep infection arising after plain and gentamicin-containing acrylic cement. There was no significant difference between the two series in primary operations, the infection rate being 1.72% and 1.65% respectively. However, in secondary operations (conversions and revisions) the gentamicin-containing cement gave significantly better results--a 0.81% infection rate as compared with 3.46%. All operations were performed in a clean air enclosure using total-body exhaust suits. Radiological diagnosis of deep infection was possible within one year of operation in all cases. Late haematogenous infection occurred in one case and was related to a skin lesion.

Adult↗
PubMed1986

Release of gentamicin from bone cement. An ex-vivo study.

Gentamycin-loaded cement from 16 patients undergoing revision of hip arthroplasty was studied. Samples removed at surgery were analyzed for gentamicin using an enzyme-linked immunoassay. Seventy-eight (55-98) per cent of the gentamicin was retained within the cement after 24 (1-48) months.

Bone Cements↗
PubMed1986

Charnley low-friction arthroplasty. Review of the past, present status, and prospects for the future.

The evolution of Charnley low-friction arthroplasty highlights the scientific basis for the operation. Long-term results show that the quality of pain relief remains excellent. The quality of the socket fixation has been improved by the use of new methods and designs, while a new technique of stem fixation has all but eliminated the loosening. Ultimately, wear and creep of the high-density polyethylene socket must be given serious consideration. Low friction remains the sound concept, and trochanteric osteotomy, now incorporating an element of compression in its reattachment, remains the method of choice for the exposure.

Follow-Up Studies↗
PubMed1986

One-stage revision of infected cemented total hip arthroplasty.

A prospective study of a one-stage revision of infected cemented total hip arthroplasty was carried out in 102 consecutive cases using acrylic cement with 0.5 g of gentamicin in each 40 g pack as well as systemic and oral antibiotics. Thirty percent had a sinus tract at some stage before the revision. The most common infecting organism was coagulase-negative Staphylococcus, either as a pure growth or in combination with other organisms. The success rate was 91%, with an average follow-up study of three years and two months. The infection persisted in 9% of the cases. In three cases, infection was correlated with some aspect of the revision technique. The method gave a higher success rate than that obtained without the use of an antibiotic-loaded acrylic cement. Combined systemic and oral use of antibiotics appears to reduce the recurrence rate still further.

Adult↗
PubMed1986

15-21-year results of the Charnley low-friction arthroplasty.

Ninety-three patients had had 116 Charnley low-friction arthroplasties (LFA) 15 to 21 years (mean, 16.6 years) previously. Their mean age at surgery was 53 years (range, 20-71 years). Fifty-two had osteoarthritis and 19 had rheumatoid arthritis. At follow-up, 85.3% were completely pain-free and 11.2% had occasional discomfort. Seventy-eight percent had near full or full range of movements. Acetabular bone-cement junction was unchanged in 32, and 20 had nonprogressive demarcation of the outer one third measuring less than 1 mm in width. In 36, socket demarcation was complete. Medial femoral cortex was unchanged in 56% and 44% showed loss of definition. Endosteal cavitation of the femur was present in 20.7%. Subsidence of the stem or the stem-cement complex was present in 29%. The diameter of the femoral cortex near the tip of the stem remained unaltered in 83.6%. The rate of socket wear was 0.096 mm/year, and there was a highly significant correlation between time and wear but no correlation between wear and patient's weight. Twenty-two and five-tenths percent of sockets migrated; this was statistically related to the depth of socket wear. The excellent clinical results of a relatively unsophisticated early surgical technique strongly supported the correct concept of the low-frictional torque. Improvements in the surgical technique and component design will further improve the long-term results.

Adult↗
PubMed1986

Long-term results of low-friction arthroplasty in patients 30 years of age or younger.

The long-term results of 49 Charnley low-friction arthroplasties performed in patients 30 years of age or younger at the time of surgery was reviewed, with special emphasis placed on the radiologic evaluation of the acetabular and femoral components with average follow-up period of nearly ten years and the longest follow-up period of 15.5 years. Fifty-three percent of the sockets had no cement-bone demarcation and 28.6% had only a small line in the upper outer quadrant of the socket. Of the seven sockets that failed (14.3%), six had very deficient bone stock at operation. There were only two cases of femoral loosening. The rate of wear was 1.7 mm at ten years, which is not much greater than in older patients. Most of these cases were patients with conditions causing built-in restraints against over activity.

Adolescent↗
PubMed1985

Reattachment of the greater trochanter after hip replacement.

A method of performing a biplanar intracapsular trochanteric osteotomy with a Gigli saw was designed and tested prospectively in 431 cases of Charnley low friction arthroplasty. Three methods of trochanteric reattachment were tested, and a double cross-over wire with a compression spring was best; this method was successful in 222 out of 226 patients (98.2%), of which half were revision operations. Adduction seemed to be the main movement leading to trochanteric detachment.

Bone Wires↗