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Biomedical subjects

C J van Loon

Publications and source records attributed to C J van Loon.

16 recordsLinked to original sources
PubMed2001

The GSB total knee arthroplasty. A medium- and long-term follow-up and survival analysis.

From 1981 to 1987, 77 GSB-II total knee arthroplasties were implanted in 65 patients. There were 23 men and 42 women aged on average 60 years old (range 30-85 years). The diagnosis was osteoarthritis (OA) in 21 knees, rheumatoid arthritis (RA) in 44 knees, and other in 12 knees. A clinical and radiological follow-up was performed in two stages after a mean of 6.7 years (61 knees) and 14.8 years (22 knees) to assess the medium- and long-term results and to determine if deterioration had occurred after mid-term follow-up. A survival analysis was done with two endpoints: (1) revision, and (2) revision, moderate or severe pain and lost to follow-up (worst-case scenario). At the last follow-up 36 patients (44 knees) had died, 2 patients (2 knees) refused examination, and 3 patients (3 knees) were lost to follow-up. Six knees had been revised for malposition (1.3%), septic (3.9%) and aseptic (2.6%) loosening. The mean Knee Society score after 6.7 and 14.8 years was 85 points (OA 82 points, RA 87 points). Lateralisation, subluxation or dislocation of the patella was present in 8 of 17 knees at the last follow-up. The 6- and 15-year survival rates with revision as the endpoint were 95% (CI 89%-100%) and 87% (CI 65%-100%), respectively. For the worst-case scenario, the 6- and 15-year survival rates were 95% (CI 89%-100%) and 56% (CI 0%-100%), respectively. The medium- and long-term results of the GSB-II total knee arthroplasty were good, and a decline in the knee score did not occur beyond the mid-term follow-up. Patella complications were abundant, and a marked decrease in implant survival was noted when moderate or severe pain and lost to follow-up were included as endpoints.

Activities of Daily Living↗
PubMed2001

Distal femoral bone mineral density after total knee arthroplasty: a comparison with general bone mineral density.

The bone mineral density (BMD) of the distal femur may decrease after cemented total knee arthroplasty (TKA) as a result of the stress shielding effect of the femoral component. The purpose of the study was to determine the changes in BMD of the distal femur compared with those of the femoral necks and the lumbar spine after cemented TKA. BMD of two regions of interest in the distal femur, both femoral necks and the lumbar spine was measured with dual-energy X-ray absorptiometry in 10 patients (age range 41-80 years, mean 62 years) with 12 TKAs preoperatively and during follow-up for 1 year after surgery. The hip and spine measurements were performed for comparison to assess if general changes in BMD occurred after TKA. The median decrease in BMD in the region behind the anterior flange of the femoral component was 22% (95% CI: 12%-33%), while the average decrease in the region just above the femoral component was 8% (95% CI: 2%-13%). The difference in change of BMD between both regions before and 1 year after TKA was significant (p = 0.03). We found less than 1% difference in BMD of both femoral necks and the lumbar spine on average between the preoperative and 1 year follow-up measurements (not significant). A significant periprosthetic distal femoral bone resorption occurred after TKA. BMD of the femoral necks and lumbar spine did not differ 1 year after TKA.

Aged↗
PubMed2001

Patient satisfaction after total knee arthroplasty: a comparison between subjective and objective outcome assessments.

We used a visual analog scale (VAS) to assess the satisfaction after total knee arthroplasty (TKA) in a group of 108 patients (126 TKAs) with short-term to medium-term follow-up. We also used the Knee Society scoring system, Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC), pain VAS, and survival analysis. A comparison between the subjective and objective outcome systems revealed only poor correlations. This comparison suggests that the concerns and priorities of patients and surgeons differ. The outcome assessed with the satisfaction VAS revealed a significantly better subjective outcome in rheumatoid arthritis patients compared with osteoarthritis patients, whereas Knee Society scores were not different. The satisfaction VAS provides additional information about subjective outcome after TKA.

Aged↗
PubMed2001

The Richards type II patellofemoral arthroplasty: 26 cases followed for 1-20 years.

We followed 26 Richards type II patellofemoral arthroplasties in 24 patients (19 women) for a mean of 11 (1-20) years. Their mean age was 59 (22-90) years. The preoperative diagnoses were primary patellofemoral arthrosis in 17 cases and secondary arthrosis in 9 (8 malalignment, 1 patellar fracture). Patellectomy was later performed for persistent pain or patellar malalignment in 3 cases and a conversion to a total knee arthroplasty for progressive tibio-femoral degeneration or patella malalignment in 2. The mean Knee Society knee score for 21 knees at follow-up was 90 (65-100) points. The patients rated the results of surgery in 9 knees as excellent, 7 good, 4 improved, and 1 unimproved at follow-up. None of the implants showed signs of loosening or infection. The Richards type II patellofemoral arthroplasty yields acceptable long-term results in patients with isolated end-stage patellofemoral osteoarthrosis. Patient selection and patella alignment are important.

Adult↗
PubMed2000

Function and complications after ablative and limb-salvage therapy in lower extremity sarcoma of bone.

BACKGROUND AND OBJECTIVES: The functional results and the complications after several limb-saving and ablative treatments because of lower extremity bone sarcoma were evaluated. METHODS: Seventy-seven surviving patients were evaluated according to the MSTS (American Musculoskeletal Tumor Society) functional rating system. Fifty-two patients had limb-saving and 25 had ablative therapy. Median follow-up was 97 months in the limb-saving group and 112 months in the ablative group. RESULTS: Functional results in the limb-saving group were significantly better than in the ablative group (P = 0.0001). Functional results in patients with tumors about the knee joint were significantly better (P = 0.0064) after limb-saving surgery (i.e., endoprosthesis, knee arthrodesis, or rotationplasty) compared to functional results after ablative surgery (i.e., hip or knee disarticulation or above-the-knee amputation). Complications were 3 times more common after limb-salvage procedures and 4 times more common after endoprosthetic reconstructions compared to after ablative procedures. Complications after limb-saving therapy were fewest in tumors about the knee joint. In 3/28 patients, the endoprosthetic reconstruction had to be converted to an amputation. CONCLUSIONS: Functional results were significantly better after limb-saving compared to after ablative therapy. Complications, however, were more common after limb-saving therapy.

Adolescent↗
PubMed2000

The role of femoral stem extension in total knee arthroplasty.

Although stemmed femoral components often are used in revision total knee arthroplasty, no quantitative comparison of the relative stability of a femoral component with and without a stem has been performed previously. A radiostereophotogrammetric analysis was performed to determine the influence of stem extension on mechanical stability in a laboratory experiment. In addition, the contribution of impacted morselized bone graft used for reconstruction of bone defects to stability was determined. Ten fresh frozen distal femoral specimens, of which the bone mineral density was measured, were prepared to fit a cemented femoral component with an uncemented stem. A cyclic axial load of 750 N was applied to the medial part of the femoral component. The loading test was repeated after creation of a standard, unicondylar, uncontained medial bone defect, after reconstruction of the defect with impacted morselized bone graft, after disconnecting the stem from the component, and after removal of the morselized bone graft. A significant difference was found in rotation and translation of the femoral component with the stem and after its functional removal. The femoral component rotated significantly into varus and internal rotation, and the tip of the stem translated significantly laterally after disconnection of the stem. A linear correlation between bone mineral density in the femoral neck and the radiostereophotogrammetric motion data was absent, but a bone mineral density threshold level of 0.55 g/cm2 was present, below which stability decreased considerably. Morselized bone graft provided only a minor contribution to stability compared with a stem.

Arthroplasty, Replacement, Knee↗
PubMed2000

Autologous morsellised bone grafting restores uncontained femoral bone defects in knee arthroplasty. An in vivo study in horses.

The properties of impacted morsellised bone graft (MBG) in revision total knee arthroplasty (TKA) were studied in 12 horses. The left hind metatarsophalangeal joint was replaced by a human TKA. The horses were then randomly divided into graft and control groups. In the graft group, a unicondylar, lateral uncontained defect was created in the third metatarsal bone and reconstructed using autologous MBG before cementing the TKA. In the control group, a cemented TKA was implanted without the bone resection and grafting procedure. After four to eight months, the animals were killed and a biomechanical loading test was performed with a cyclic load equivalent to the horse's body-weight to study mechanical stability. After removal of the prosthesis, the distal third metatarsal bone was studied radiologically, histologically and by quantitative and micro CT. Biomechanical testing showed that the differences in deformation between the graft and the control condyles were not significant for either elastic or time-dependent deformations. The differences in bone mineral density (BMD) between the graft and the control condyles were not significant. The BMD of the MBG was significantly lower than that in the other regions in the same limb. Micro CT showed a significant difference in the degree of anisotropy between the graft and host bone, even although the structure of the area of the MBG had trabecular orientation in the direction of the axial load. Histological analysis revealed that all the grafts were revascularised and completely incorporated into a new trabecular structure with few or no remnants of graft. Our study provides a basis for the clinical application of this technique with MBG in revision TKA.

Animals↗
PubMed2000

The kinematic total knee arthroplasty. A 10- to 15-year follow-up and survival analysis.

In 86 patients 102 consecutive cemented Kinematic total knee arthroplasties were reviewed 10-15 years after surgery to determine the clinical and radiographic results and to assess the survival rate. The average age of the 65 female and 21 male patients at the time of surgery was 63 years. Forty-six knees were affected by rheumatoid arthritis (RA), 46 by osteoarthritis (OA), 7 by haemophilic arthropathy and 3 by osteonecrosis. One patient (1 knee) was lost to follow-up, and 31 patients (38 knees) died. Eleven knees had been revised for deep infection (4), wear (4), malposition (2) or persistent pain (1). Fifty-two knees were examined at an average follow-up period of 12 years. The mean Knee Society Score of 89 points was the same for RA and AO knees. Also, 92% of the knees caused no pain or only occasional mild pain. There were no cases of aseptic loosening of any component. Progressive radiolucent lines were not seen on the follow-up radiographs (43 knees, mean follow-up 12 years) The 10- and 14-year survival rates with revision as the end-point were 90% (confidence interval, CI: 81%-95%) and 82% (CI: 67%-92%), respectively. In the worst case scenario, with knees lost to follow-up and knees with moderate pain considered as failures, the 10- and 14-year survival rates were 80% (CI: 69%-88%) and 62% (CI: 46%-77%), respectively. The Kinematic total knee arthroplasty yields equally good long-term results in patients with RA and those with OA. Deep infection and wear were the main reasons for revision.

Adult↗
PubMed1999

Morsellized bone grafting compensates for femoral bone loss in revision total knee arthroplasty. An experimental study.

This study was undertaken to examine the contribution of uncontained morsellized bone graft to the structural properties of a femoral reconstruction in total knee arthroplasty and to serve as a basis for an in vivo animal study. Ten human distal femora with a standard unicondylar uncontained medial bone defect were prepared to fit a femoral component of a cruciate sacrificing TKA. A cyclic axial load of 750 N was applied to the medial part of the femoral component in the presence of impacted morsellized bone graft. After removal of the bone graft, the cyclic loading was repeated for the unsupported situation. None of the grafts collapsed and all cement mantles stayed intact during the experiments. Elastic deformation during cyclic loading was significantly less when graft was added while time-dependent deformation was not affected. We conclude that impacted morsellized bone graft, used for reconstruction of uncontained femoral bone loss in revision knee arthroplasty, may improve the structural resistance against loading. Further animal experimentation for in vivo application is warranted.

Animals↗
PubMed1999

Femoral bone loss in total knee arthroplasty. A review.

Femoral bone loss in total knee arthroplasty (TKA) is a common feature and is mainly attributed to three etiological factors. Stress shielding causes an "osteopenia" type of bone loss behind the anterior flange and adjacent to the distal aspects of the femoral component. Using dual-energy x-ray absorptiometry, decrease in bone mineral density up to 44% has been measured in these areas. Secondly, polyethylene, cement and metal particles are released by implant wear and may cause the less common "osteolysis" type of bone loss located directly at the anterior and posterior implant-cement-bone interfaces. This type of bone loss occurs mainly in young, male, overweight patients with osteoarthritis. Finally, implant loosening leads to bone loss at the bone cement-implant interface and results in "hollowing out" of the distal femur in a stemmed TKA. Femoral bone loss may be reduced by diminishing the stress-shielding effect, by improving the quality of the polyethylene insert, and by decreasing the rate of implant loosening still further. In revision TKA, femoral bone loss is often underestimated in the preoperative radiographs. Classification of bone loss should be made during surgery, and should be based upon the size of the defect generated and the grade of containment. The choice among cement filling, metal augmentation, custom-made TKA, solid bone grafts, and morsellized bone grafts in reconstruction of bone defects will depend upon the type of bone loss, the bone quality, the surgeon's preference and philosophy, and the availability of grafts and implants.

Absorptiometry, Photon↗
PubMed1999

Femoral bone grafting in primary and revision total knee arthroplasty.

The purpose of this study was to evaluate the clinical and radiographic results of TKA's with morsellized and solid femoral bone grafting. From April 1989 to February 1996, 6 primary and 18 revision TKA's with femoral bone grafting were performed in 22 patients with an average age of 62 years. Eleven knees were affected by rheumatoid arthritis, 10 by osteoarthritis, 2 by osteonecrosis and one by hemophiliac arthropathy. The femoral bone defects were large in 12, medium in 9, small in 3, contained in 10 and uncontained in 14 cases. Reconstruction was done with impacted morsellized fresh frozen trabecular bone grafts in 13 knees, with solid bone grafts in 7 knees and with combined grafts in 4 knees. Twenty-one cases were clinically evaluated at an average of 38 months (range: 9-89 months). The average Knee Society knee score increased by 39 points to 85 points at follow-up. The average functional score increased by 22 points to 48 points. Two cases with solid femoral bone grafts failed due to aseptic loosening. There were no infections. Radiographic follow-up revealed osteopenia around the femoral component in 10 knees. Two knees showed circumferential radiolucency around the femoral stem, and 5 knees had minor radiolucency at the anterior part of the femoral component. Radiographic incorporation was present in 5 of the 6 cases that could be evaluated. Histologic analysis of two biopsies revealed incorporation of the morsellized bone graft. The authors advocate impacted morsellized bone grafting for contained and small-to-medium uncontained femoral bone defects in combination with cemented TKA.

Adult↗
PubMed1995

Aneurysmal bone cyst. Long-term results and functional evaluation.

A study was performed on 13 patients with 16 primary aneurysmal bone cysts (ABC) to assess long-term results and functional outcome. The average age at diagnosis was 19.8 years. The anatomical sites were femur (4), tibia (5), humerus (2), fibula (2) and other (3). Four ABC's required no treatment. One patient underwent radiotherapy for an ABC of the spine. Eleven ABC's were treated surgically, mostly by intracapsular resection and bone grafting. Three patients had a total of 6 recurrences, which needed further treatment. At the time of follow-up (average period: 102 months), the average functional evaluation rate of 13 patients was 96%. These functional results were graded as excellent in 9 patients and good in 4.

Adolescent↗
PubMed1994

[Primary treatment of unstable pertrochanteric femoral fractures using a head-neck prosthesis in elderly patients].

OBJECTIVE: Evaluation of the treatment of unstable pertrochanteric femoral fractures with a femoral head prosthesis in older patients. DESIGN: Descriptive. SETTING: University Hospital Nijmegen, the Netherlands. METHOD: From January 1988 through December 1992, 15 patients with 15 unstable pertrochanteric femoral fractures were treated with a femoral head prosthesis and additional wiring of the trochanter. The group consisted of 11 women and 4 men with a mean age of 86 years. Two operations were secondary treatments after broken angled-plate fixation. The other 13 were primary treatments. RESULTS: A stable fixation allowing weight-bearing was achieved in all cases. The operations were accompanied by high morbidity and mortality rates: 4 patients died within 3 months after surgery. One dislocation of the prosthesis occurred. Twelve fractures consolidated, pseudarthrosis of the greater trochanter occurred twice. Five patients regained their preoperative walking ability. CONCLUSION: Femoral head prosthesis with additional wiring is an alternative with few mechanical complications in the treatment of unstable pertrochanteric femoral fractures.

Aged↗
PubMed1994

Chondrosarcoma of bone: oncologic and functional results.

A retrospective review of 27 patients (21 males and 6 females) with chondrosarcoma of bone was performed to evaluate the oncologic and functional results. The average age of the patients was 48 years (range: 17-76). The tumor sites were pelvis in 10 cases, distal femur in 2, proximal tibia in 3, rib in 2, and other in 10. One patient with Ollier's disease had chondrosarcoma at two different sites simultaneously. Surgical stages were I A in 8 cases, I B in 8, II A in 1, and II B in 10. Two patients had no surgical treatment. Amputation was performed in 5 cases and en bloc resection in 20. An uncontaminated radical or wide surgical margin was achieved in 13 of 25 cases. Additional surgery was performed in seven cases; for deep infection in one case and for local recurrence or metastasis in six. Local recurrence developed in seven patients (26%). At follow-up, four patients had died of disease (15%), one patient had died of another cause, and two patients were alive with disease (7%). No evidence of disease was found in 20 patients (74%). The oncologic results of limb salvage and amputation in chondrosarcoma of the limbs were good, although there was one failure of limb salvage, caused by infection. Due to surgical inaccessibility, results of the management of chondrosarcoma of the pelvis were poor. The average functional evaluation of 16 patients (average follow-up: 104 months) was 75% (range: 30-100). The Musculoskeletal Tumor Society ratings were excellent in four cases, good in seven, fair in four, and poor in one.

Adolescent↗
PubMed1993

The Geomedic knee prosthesis. A long-term follow-up study.

A retrospective long-term follow-up study of 189 Geomedic total knee arthroplasties in 143 patients was performed. One hundred and eighteen knees were replaced in patients with rheumatoid arthritis and seventy-one knees were replaced in patients with osteoarthritis. Fifty-seven knees were examined clinically with an average follow-up of 11 years. Seventy percent of these knees were painless. Lucent lines at the tibial bone-cement interface were observed in 62% of the follow-up radiographs (81 knees, mean follow-up: 10.5 years). Thirty-four prostheses (18%) were removed, with loosening of the tibial component as the main cause. Retropatellar pain was not a significant problem. The 13-year survival rate was 78%, with implant removal as an endpoint. Radiographically loosened components included, the 13-year survival rate was 58%.

Adult↗