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Biomedical subjects

K Rechnagel

Publications and source records attributed to K Rechnagel.

At least 19 recordsLinked to original sources

[Non-cemented acetabular cup in hip arthroplasty. Prosthesis survival and clinical results after 1-8 years].

This is a retrospective clinical evaluation of 1028 primary hip arthroplasties performed with the non-cemented Harris-Galante I acetabulaer cup. Hospital records regarding all hips operated from July 1985 through March 1992 were evaluated after a median of 48 (12-93) months. Furthermore, questionnaires were sent out to all patients still alive in order to establish the actual function of the hips. At time of evaluation, 43 of the 1028 primary acetabular cups (4.2%) had been or were due to be revised. (20 because of one or more episodes of dislocation or displacement of the cup, 10 due to deep infection, eight following aseptic loosening of the cup, two because of implant failure and three due to other reasons). Four hundred and twenty-six hips were without pain, 274 had only mild or slight pain, whereas 84 experienced moderate or worse pain. We conclude, that the results after non-cemented hemispheric acetabular arthroplasties in this study are satisfying with a low rate of aseptic loosening.

Acetabulum↗

Evaluation of 100 Müller curved-stem and 276 Müller long-stem total hip arthroplasties after 10 to 15 years of follow-up.

This study evaluates 376 total hip arthroplasties performed between 1978 and 1983 using 276 Müller long-stem and 100 Müller curved-stem prostheses. Demographic and clinical data were obtained from patient records. All patients still alive who did not undergo revision arthroplasty were sent a detailed questionnaire. Results indicated that long-term survival of the femoral component of the arthroplasty was significantly better when the Müller long-stem was used. Furthermore, there was no difference in the clinical out-come between patients who underwent revision and those who did not. To eliminate demographic differences between the two groups, 77 patients from each group were paired. There was no difference in clinical results of the hips between the paired groups, and long-term survival of the Müller long-stem was still significantly better using Kaplan-Meier analysis.

Adult↗

Cementless AGC revision of unicompartmental knee arthroplasty.

Twenty-eight patients (29 knees) who had revision of a failed unicompartmental knee arthroplasty to total knee arthroplasty were evaluated. All revisions were made with cementless technique using the AGC prosthesis (Biomet, Warsaw, IN). Major osseous defects were found in 20 knees, and bone-grafting was used to fill the defects. Aseptic loosening and progression of osteoarthrosis were the main reasons for revision. The median follow-up period was 38 months. Twenty knees were excellent or good, four fair, and five poor. One tibial component had been revised because of loosening. Three knees with instability had been reoperated with a thicker polyethylene component, but one of these patients still suffered from instability, and revision with a constrained prosthesis was planned. One was revised after a deep infection. Two tibial components were suspected to be loose because radiographs exposed fluoroscopically revealed a complete radiolucent line under the component. The results with cementless revision and bone-grafting are comparable to the results achieved after cemented revision, and cementless revision is recommended in young patients and in patients with major bone loss.

Aged↗

Cementless total knee arthroplasty in rheumatoid arthritis. A report on 51 AGC knees followed for 54 months.

Fifty-one primary consecutive cementless AGC 2000 (Anatomically Graduated Components, Biomet, Warsaw, IN) total knee arthroplasties were performed during 1985 through 1990 in 40 patients with rheumatoid arthritis. Forty-one knees (32 patients) were available for clinical and radiologic follow-up analysis after 24 to 76 months (median, 54 months). There was no pain in 33 knees and mild pain in the rest. Median range of motion was 110 degrees (range, 50 degrees-130 degrees). Median knee score was 90 (range, 71-97), and all knees were rated good or excellent. Radiolucencies greater than 1 mm were found under five tibial components, but no obvious migrations were seen. One tibial component was revised due to aseptic loosening. The cumulative success rate after 4 to 5 years was 97% (lower limit of 95% confidence interval, 91.8%). The medium-term results are considered to compare favorably with reported cemented series.

Adult↗

Survival of autotransfused red cells. 51Cr studies in 10 knee arthroplasty patients.

We determined the long-term survival of red blood cells collected postoperatively from the surgical drains, filtered and autotransfused with the Constavac Blood Conservation System. 10 patients with knee arthrosis were treated with cementless total knee arthroplasty and postoperatively connected to the autotransfusion system. Shed blood was collected for 6 hours postoperatively and then reinfused. Before reinfusion, a fraction of the blood shed was radiolabeled with chromium-51 (51Cr). For a postoperative minimum period of 40 days the activity of 51Cr was measured in frequent venous blood samples. The time from 100% to 50% activity of the isotope (T50Cr) was 21 days, equal to that reported for banked autologous blood.

Blood Transfusion, Autologous↗

Cementless total knee arthroplasty in unselected cases of osteoarthritis and rheumatoid arthritis. A 3-year follow-up study of 103 cases.

The authors reviewed 103 cementless AGC 2000 total knee arthroplasties in unselected cases of osteoarthritis and rheumatoid arthritis with a follow-up period of 3 years. Excellent or good clinical results were obtained in 96%. The median maximal flexion was 110 degrees. Two aseptic loosenings of the tibial components had been revised prior to this evaluation. Two other patients showed radiographic signs of tibial loosening but were asymptomatic. Undersizing of the tibial component predisposes to subsidence and loosening. One had septic tibial loosening planned for revision. Four had nonprogressive lucent lines beneath the tibial tray but were asymptomatic. No patellar or femoral component loosening was revealed. Undercorrection of preoperative varus deformity did not dispose to tibial loosening or radiolucency, nor influence the clinical result. In terms of survival of the prosthesis the cumulative success rate was 97.1%. When pain and radiographic loosening was also considered, the success rate was 90.7%. These results encourage uncemented use of this prosthesis, but emphasize the importance of good primary prosthetic fit at the tibial side.

Adult↗

Long-term follow-up of the cemented Caffinière prosthesis for trapezio-metacarpal arthroplasty.

20 patients with 22 Caffinière prostheses in the trapezio-metacarpal joint were evaluated at a median of nine years after operation. The indication was degenerative osteoarthrosis in 20 cases and rheumatoid arthritis in two cases. We found 18 of the 22 (82%) original prostheses still in place, with satisfactory pain relief and good function. Three hands had been revised due to aseptic loosening, with replacement of two cups and one total prosthesis. Two of the revised prostheses were functioning well 6 1/2 and 10 years after the revision. We conclude that function does not deteriorate within the first nine years, that late loosening is not a significant problem with this prosthesis and that, if aseptic loosening occurs, it is possible to obtain good results by replacing the loose component.

Aged↗

Histologic analysis of a retrieved hydroxyapatite-coated femoral prosthesis.

A hydroxyapatite-coated hip hemi-prosthesis was retrieved from a 98-year-old osteoporotic woman 12 weeks after implantation. Histologic analysis revealed bone and fibrous tissue almost evenly distributed around the surface of the implant circumference. Quantitative histologic analysis showed that 48% of the hydroxyapatite surface was covered by bone. Fibrous tissue covered 30% of the prosthetic surface, and 20% of the surface had no tissue coverage. Scanning electron microscopy showed direct contact without any clear boundary between the newly formed bone and the hydroxyapatite ceramic.

Aged↗

Replacement of the trapeziometacarpal joint with a cemented (Caffinière) prosthesis.

Between 1978 and 1985, 31 Caffinière prostheses were implanted in the first carpometacarpal joints of 28 patients for treatment of degenerative osteoarthritis (26 patients) or rheumatoid arthritis (2 patients). At follow-up an average of 48 (13 to 77) months after operation, four hands had reoperation, with the replacement of six components, five cups and one metacarpal component. In addition, there were x-ray signs of component loosening in three other cases. Of the 29 thumbs that could be evaluated with regard to pain, 27 had no pain at all or only slight pain, and two patients had moderate pain. No patient suffered from severely disabling pain. Mobility and strength were satisfactory.

Adult↗

Porous-coated knee arthroplasty. A case report concerning bone ingrowth.

The area of bone-metal interaction in uncemented implants is regarded by many investigators as the key to the success or failure of the implant. The nature of the interaction is poorly understood because the zone is technically difficult to visualize and analyze. In order to test the power of modern imaging, analyzing, and metallurgical methods in this context, a well-functioning porous-coated knee prosthesis (tibial component) removed from the knee of a 65-year-old man was sectioned and examined by light microscopy, roentgenogram, scanning electron microscopy, and radiologic energy dispersive analysis. Independently, these methods demonstrated that the prosthesis was held in situ by collagenous tissue between and below the metal pellets of the prosthesis. Calcified bone did not appear to interact with the prosthesis and is probably not a major factor for prosthesis fixation. The various analytic methods described are suitable and sufficient for further exploration on a larger scale of the zone of bone-metal contact in cementless implants.

Aged↗

No effect of continuous passive motion after arthroplasty of the knee.

We randomly allocated 54 patients to active physical therapy only or this combined with 2 hours of passive knee motion twice daily from 2-12 days after total knee arthroplasty. The range of knee motion was measured on the 14th postoperative day. We found no difference between the groups. We concluded that 4 hours' passive motion daily in addition to early, active physical therapy does not improve the range of knee motion or promote mobilization after arthroplasty.

Adult↗

The Monk hip arthroplasty. Preliminary report on the uncemented standard Monk prosthesis.

The Monk hip prosthesis is a one-piece block prosthesis consisting of a metal femoral component with the head enclosed in a polyethylene cup. The standard type is fixed without cement. Most of the hip movements take place between the metal and the polyethylene cup. 104 Monk arthroplasties were performed. 95 hips in 84 patients have been available for regular examination and follow-up. The follow-up period was from 12 to 30 months, an average of 19 months. Out of the 95 cases, 72 were classified as excellent, 10 as good and 13 as unchanged. The results obtained during the first year were comparable to those obtained with the Ring prosthesis, but during the following 1 1/2 years eight revisions had to be performed. The main reason for the deterioration was loosening of the femoral component, probably because in the standard type it is too short and the neck has too great a varus inclination, resulting in a rather strong tilting force. Because no cement has been used the revisions have been quite easy to perform. Another reason for failure has been wear of the polyethylene cup, in one case with a massive foreign body reaction. In spite of a short follow-up period this report illustrates the failures due to the design of the prosthesis, and therefore an improved construction is now in use.

Adult↗