Wear of the Christiansen hip prosthesis

The wear was examined in 39 Christiansen total hip prostheses, which were removed because of mechanical loosening after being used 5 (3-11) years. In the polyacetal acetabular cups, the head had made an eccentric defect, the mean volume of which was 680 (180-3310) mm3. The mean penetration of the head into the wall of the cup was 0.8 (0.1-3.2) mm. In two additional cups the head had penetrated right through the wall of the cup. In three prostheses the polyacetal sleeve of the trunnion was so worn that the head bore directly on the stem. There was a positive correlation between wear and the time the prostheses had been used before symptoms of loosening presented.     

Ten to twelve-year results with the Zweymüller cementless total hip prosthesis

Between January 1987 and December 1990, 221 Zweymüller cementless total hip arthroplasties were performed in 211 patients with idiopathic osteoarthritis. A total of 136 patients (142 prostheses) were evaluated at a mean follow-up of 134 months (SD 9.5). The study group consisted of 78 Hochgezogen and 64 Stepless stem prostheses, all with a threaded titanium cup and ceramic head. No clinical and radiological differences were found between the 2 stem prostheses. Seven cups had been revised because of aseptic loosening; 17 cups showed radiolucent lines, osteolysis, or migration. Mean linear polyethylene wear of 105 (74%) cups was 0.46 mm (SD 0.27), with an annual wear of 0.04 mm (SD 0.02). Wear did not correlate with pain, cup migration, radiolucent lines, or osteolysis. Cumulative survival was 96%. Zweymüller cementless total hip arthroplasty showed good midterm results.     

Midterm survivorship of a press-fit, plasma-sprayed, tri-spike acetabular component

Press-fit acetabular cups without screw holes can limit migration of particulate wear debris and reduce risk of acetabular osteolysis and device loosening. The Tri-Spike cup (Biomet, Inc, Warsaw, Ind) includes a titanium alloy plasma spray porous surface and does not require screw fixation. We retrospectively examined the incidence of cup loosening and acetabular osteolysis after implantation of 45 cups (44 patients) with mean follow-up of 7.3 years (range, 4-9 years). Only one patient (one cup) had evidence of less than 1 mm of retroacetabular radiolucency at 3 years (nonprogressive), which was found to remain firmly fixed during revision of the aseptically loosened femoral component. No cups were removed or revised at latest follow-up. Projected Kaplan-Meier survivorship at 9 years was 100% for cup loosening/revision and 97.8% for radiolucency.     

Results of the uncemented total hip arthroplasty in avascular necrosis of the femoral head]

AIM OF THE STUDY: The results from 56 patients with osteonecrosis of the femoral head who underwent 66 uncemented total hip replacements were analyzed and compared with current reports in the literature on cemented endoprosthesis. METHODS: In the retrospective study in 30 of those cases the Zweymüller and in 25 cases the HA-coated ABG prosthesis were used. In addition the results of 11 patients with a polyethylene Endler cup in combination with a Zweymüller stem are presented. The mean age at surgery was 48 years, the mean follow-up was 5.9 years. Clinical examination, registration of the Merle d'Aubigné score and a radiological examination were performed. RESULTS: The clinical results did not show any differences between the used prostheses. A more favourable outcome with regard to the Merle d'Aubigné score was demonstrated for the Zweymüller and ABG prostheses. No loosening of the stem was found. Revision as a consequence of aseptic loosening of the acetabular component was done in 7,5 % (27,3 % of the Endler cups and 8 % of the ABG cups). 20 % of the patients with an ABG prosthesis showed acetabular osteolysis of various degrees. This seems to be correlated with an increased polyethylene wear. CONCLUSION: Recent reports in the literature about a favourable outcome in uncemented total hip arthroplasty in osteonecrosis of the femoral head can be confirmed. The unsatisfactory results of the Endler cup indicate that established types of endoprostheses should be preferred.     

Modes of failure of a threaded acetabular cup

A radiographic study of a singular type of threaded cup, revised due to aseptic loosening, was performed with Einzel-Bild-Roentgen-Analyse (EBRA) to detect eventual risk factors and patterns of loosening. Fifty-three cups of 50 patients were revised. Forty-two cups could be measured with EBRA. No cup had obvious osteolysis, 33 cups demonstrated early migration, and all cups had migrated at the time of revision. Twenty-eight of the cups had a change of inclination and 21 of anteversion, respectively. The mean migration was 1.9 mm in the medial and 7.9 mm in the cranial direction; the mean wear rate was 0.2 mm/year. Cups with early migration had a higher migration rate. All male patients had early migration; medially placed cups had less migration than the other cups. Wear was not significantly affected by the migration of the implant. No cup had a complete radiolucent line, and the only radiographic sign for loosening was the change of position of the cup. Medial placement showed less migration in case of loosening. Regular radiographic follow-up is recommended for the examined implant, and the cup should not be used in the future.     

Wear of polyethylene acetabular cups against alumina femoral heads: 5 prostheses compared in a hip simulator for 35 million walking cycles

5 ultra-high molecular weight polyethylene acetabular cups articulated against alumina femoral heads for 35 million walking cycles in a hip joint simulator designed for wear tests of total hip prostheses. The specimens were from Protek, Biomet, Link, Howmedica and Thackray. In the Howmedica specimen, the wear was zero, and in Link and Thackray practically negligible. In Biomet, however, the wear was noteworthy and in Protek disastrous after 20 million cycles because in these 2 prostheses the head was attached to a titanium-alloy stem by taper-fit: titanium-alloy particles that were removed from the taper because of micromotion between the head and stem were entrapped between the head and cup, adhering to the head and making it rough, which led to severe abrasive wear of the Protek cup. It was worn through at 26 million cycles, the total wear being 3,170 mg. In Biomet, Link and Thackray, the total wear was 124, 5.3 and 17.6 mg, respectively. Polyethylene wear particles may lead to adverse tissue reactions and eventual loosening of the implant. The results indicate that by the use of alumina heads, polyethylene wear can be eliminated, but this advantage may be lost if the head is attached to a titaniumalloy taper.     

The Harris-Galante total hip arthroplasty: a minimum 8-year follow-up study

A total of 93 Harris-Galante Porous I (HGP- I) prostheses were analyzed with a mean follow-up of 10.2 years. Thigh pain (28 hips) correlated with unstable fixation (P<.005), female gender (P<.045), young age (P<.05), poor distal femoral fill (P<.002), subsidence (P<.0001), and osteolysis (P<.05). Thirteen stems and 6 metallic shell cups were revised. Kaplan-Meier analysis showed 13-year survival rates of 92.5% +/- 5.8% for the metallic shell cup, 79.7% +/- 13% for the HGP-I cup, and 76.3% +/- 14.0% for the stem. Five polyethylene liners were changed because of wear >1 mm. Radiographic loosening occurred in 8 cups. Radiographic bone ingrowth was present in 54 stems, stable fibrous fixation was present in 24 stems, and unstable fixation was present in 15 stems. The mean polyethylene wear was 0.17 mm/y. Eleven hips (11.8%) had acetabular osteolysis, and 24 (25.8%) had femoral osteolysis, the latter being more frequent in unstable stems (P<.007). The HGP-I metallic cup shows better clinical and radiographic results than the stem, which frequently is associated with pain, unstable fixation, and osteolysis. Excessive polyethylene wear is frequent.     

Experiences with the Plasmacup--early stability, wear, remodelling, and outcome

Whilst advances in cementing technique have led to improvement in the survival of cemented femoral stems in total hip arthroplasty (THA), cup failure due to aseptic loosening remains a major clinical problem. These observations have led to a move away from cemented cup designs, particularly in young patients, towards uncemented implants. The Plasmacup is a hemispherical, press-fit, cementless, titanium-shelled, acetabular component with a polyethylene liner. In this article we review our experience of its pattern of early migration, wear, bone remodelling, and mid-term survival. In 18 cups followed for 2 years in subjects with a mean age at operation of 58 years, the mean total vectorial cup migration was 0.75 mm, and cup orientation remained stable (EBRA method). The mean polyethylene linear wear rate over this period was 0.21 mm/year. In 27 cups followed for 6 months using dual-energy X-ray absorptiometry (DXA), average bone loss was -5%, and the pelvic bone-remodelling pattern was consistent with the rim-loading principle of the cup design. In a clinical review of the outcome of 128 cups in 104 patients with a mean age at operation of 51 years and follow-up of 59 months, we found that 82% of patients had a good or very good Merle D'Aubigne score, and cup survival rate was 98% (Kaplan-Meier). Four cups had small radiographic areas of focal osteolysis and three had been revised (two for recurrent dislocation and one for deep sepsis; none were revised for aseptic loosening). The mean linear wear rate in this series was 0.14 mm/year. In conclusion, the Plasmacup shows satisfactory early stability, a wear rate similar to other uncemented cups, and favourable mid-term clinical function and survival rates.     

Versagensgründe von Oberflächenersatzimplantaten der Hüfte

Hip resurfacing has been experiencing a revival over the last 5-10 years. Early failure rates are higher than for conventional primary hip arthroplasty. Fractures of the femoral neck or head, cup loosening and persistent pain are the most frequently observed reasons for early revision. In this international retrospective uncontrolled study, 256 revision specimens (219 resurfacing heads, 37 cups) were analysed radiologically, tribologically, morphologically and histologically in order to investigate the failure mechanism. Of the head revisions, 70% were due to neck (median: 67 days after implantation) and head fractures (161 days), 9% were due to cup loosening (350 days) and 21% due to other reasons (602 days). Implants with rim loading (22% of all retrievals, cup inclination 58.0+/-10.9 degrees ) exhibited a head wear rate of 7.1+/-5.2 mm3/year. Non-rim loaded implants exhibited a head wear rate of 0.24+/-0.53 mm3/year (cup inclination 49.0+/-4.0 degrees ). The failure rate was highest during the first 16 weeks after surgery and for the first ten operations performed by a surgeon. Revisions based on problems on the femoral side such as notching and high implantation forces occurred earlier than revisions based on problems on the acetabular side such as cup loosening and high wear due to suboptimal cup position.     

Cementless acetabular replacement in patients with rheumatoid arthritis: a 6- to 14-year prospective study

Sixty-three consecutive patients who had 82 Harris-Galante porous acetabular cups (HGP1) (Zimmer Inc, Warsaw, IN) implanted for the treatment of rheumatoid arthritis were prospectively assessed since 1986. At last examination, 12 patients (16 hips) had died, and 1 patient (1 hip) was lost to follow-up. A total of 65 hips in 50 patients were available for the latest review. The follow-up period was 6.8 years to 14 years (mean, 9.1 years). There had been 6 revisions: 1 for deep infection and 5 for polyethylene cup wear. Survivorship analysis for all failures estimated that 75% of hips would still be revision-free after 4558 days (12.5 years). Polyethylene wear has been identified in a further 7 cases at last examination. The average linear cup wear per year was 0.05 mm(range, 0.00-0.66 mm). There were no cases of acetabular loosening or acetabular migration. These results demonstrate the excellent durability of fixation of the HGP1 cups in patients with rheumatoid arthritis. However, a 32-mm head should probably not be used with this cup given the high associated incidence of polyethylene wear.     

The performance of two hydroxyapatite-coated acetabular cups compared with Charnley cups. From the Norwegian Arthroplasty Register

We have compared the survival of two hydroxyapatite (HA)-coated cups, 1208 Atoll hemispheric and 2641 Tropic threaded, with cemented Charnley all-polyethylene cups (16 021) using the Cox regression model. The Tropic cup used in combination with an alumina ceramic femoral head, had good results, similar to those of the Charnley cup. When used in combination with a stainless-steel head, however, the risk of revision beyond four years was increased 3.4 times for the Tropic cup compared with the Charnley cup (p < 0.001). Over the same period, the Atoll cup had an increased risk of revision of 3.8 times when used with the alumina heads (p < 0.001) and an increased risk of 6.1 times when used with stainless-steel heads (p < 0.001). Revision because of wear and osteolysis was more common with both types of HA-coated cup than with the Charnley cup. The rate of revision of the Atoll cup because of aseptic loosening was also increased. We found that HA-coated cups did not perform better than the Charnley cup.     

Radiographic and clinical analysis of cementless acetabular fixation in total hip arthroplasty

Tofruetancloc nthisoitpnru sac.rttih oOrnorpig ltaiensctahylln y(i,qTuH emAa)jfoo irrs a Td HweteAelrli-o etrseatctaehbdnliiqs huheeidpsutilized bone cement for fixation,but loosening rate ofthe acetabular component was very high because ofbone cement tec…     

High osteolysis and revision rate with the hydroxyapatite-coated ABG hip prostheses: 65 hips in 56 young patients followed for 5-9 years

BACKGROUND: There are few reports on the outcome of uncemented HA-coated cups in young patients. PATIENTS: I evaluated the 7-year (5-9) results of HA-coated hip prosthesis (ABG, Stryker) in a consecutive series of 65 primary arthroplasties on 56 patients (mean age 44 years). 2 patients were lost to follow-up and 3 died. RESULTS: The cumulative survival rate with revision for any reason as endpoint at 9 years was 98% (95% CI, 96-100) for the stem, 69% (61-77) for the acetabular metal backing, and 59% (50-67) for the polyethylene liner. 15 of 65 cups were revised on average 6 years after the primary operation and 3 more are planned. Revisions were done in 3 hips because of loosening and migration of the cup, and in 12 hips because of wear and progressive osteolysis around stable components. Only hips with migration had clinical symptoms. Visual inspection of polyethylene liners revealed wear of the articulation in all cases, loosening of the locking mechanism in 10 cases and nonarticular surface deformity in 7 hips. All original stems are in situ although femoral osteolysis was seen in 12 cases and 1 hip was reoperated because of periprosthetic traumatic fracture. Despite the high revision rate, the clinical improvement was good: the average pre- and postoperative Harris Hip Scores at the most recent follow-up were 41 and 90, respectively. INTERPRETATION: While the results on the femoral side were good, the survival rates of the acetabular cups were poor and we stopped using ABG I hip prostheses.     

Charnley low-frictional torque arthroplasty for avascular necrosis of the femoral head

Forty-nine patients (mean age, 37 years; 20-50 years) had had 69 Charnley low-frictional arthroplasties for avascular necrosis of the femoral head. Their mean follow-up was 13.4 years (2-25 years). Five patients (8 hips) had no continuing follow-up, 5 (8 hips) are known to have died, 6 (7 hips) had had a revision at a mean follow-up of 16.4 years (11-25 years): 6 for cup loosening and 1 for a fractured stem and a loose cup. The remaining 33 patients (46 hips) had an excellent clinical result with all stems remaining soundly fixed, but 6 cups were radiologically loose at a mean follow-up of 16 years and 4 months. Wear and cup loosening are the main problems limiting the survival of the arthroplasty.     

Wear and periprosthetic osteolysis of modular, hemispheric acetabular cups]

Osteolysis associated with polyethylene wear has become one of the most prevalent complications associated with uncemented modular, hemispherical cups. Sixty-five consecutive total hip arthroplasties (ABG i, Howmedica, Stryker) were followed 6-12 years. Cumulative survivorship for the cup was 55.7% after 10 years. There were 20 cups revisions because of polyethylene wear and periprosthetic osteolysis (14 cups) or cup loosening (6 cups). Stability was assessed intraoperatively, 14 cups were revised, whereas 6 new polyethylene cups were cemented into stable metal-back of acetabular component. The average annual wear of revised cups was 0.32 mm. The annual wear of not revised cups was 0.12 mm. The differences were statistically significant (p = 0.002). The mean area of osteolysis was 472 mm2 (SD 257 mm2). There was no significant correlation between wear and area of osteolysis. There was significant correlation R = 0.54, p = 0.014) between time to revision and area of osteolysis. There were no significant differences of wear of polyethylene inlay or area of osteolysis between stable and unstable acetabular cups.     

Total hip arthroplasty in patients less than 40 years old with avascular necrosis of the femoral head. A 5 to 19-year follow-up study

We evaluated 34 total hip arthroplasties (THA) for avascular necrosis of the femoral head in 26 patients who were younger than 40 years at the time of the index operation. The average age at the time of THA was 283 (17-38) years. The mean follow-up was 10.9 (5-19) years. We used 6 cemented and 28 cementless acetabular components and a cemented polished tapered stem in all hips. The mean Charnley modified Merle d' Aubigné Postel score was 8.9 points preoperatively and 16.6 points at final follow-up. Two cemented metal-backed cups were revised because of aseptic loosening at 10 years, one cemented polyethylene cup failed at 12 years and 2 more all polyethylene cups had pending failure. The metal-backed cemented cups and the all polyethylene cups had a longer follow-up than the uncemented cups. Therefore and because of the proven unfavourable long-term outcome of the cemented metal-backed Exeter cup we are not able to draw any firm conclusions regarding the preferred choice between cemented and uncemented cups in this particular group of patients. On the femoral site none of the stems had to be revised. Our results show that a cemented polished tapered femoral component has an excellent survival in primary total hip replacement in young patients with avascular necrosis of the femoral head.     

Correlation of wear debris-induced osteolysis and revision with volumetric wear-rates of polyethylene: A survey of 8 reports in the literature

This survey focused on clinical reports of polyethylene wear and osteolysis in total hip replacements. With regard to documentation of clinical wear-rates, 57 publications were reduced to an analysis of 8 reports of THR series, including the incidence of osteolysis. A direct correlation was found among volumetric wear rates, incidence of osteolysis and revision rates in THR concepts of the 1983-1987 era. As volumetric wear rate increased, the incidence of osteolysis and revision rates increased. With regard to our grading system for volumetric wear, with follow-up in the 4-15 year range, osteolysis was rare in group A (wear = 0-80 mm 3 /year), ranging from 6% to 31% in group B (wear 40-80 mm 3 /year) and from 21% to 100% in group C (wear > 140 mm 3 /year). With regard to cup design, the optimal low-wear group had mainly cemented polyethylene cups with 22 and 28 mm head sizes. The mid-wear group B had metal-backed cemented and uncemented cups, with 28 mm head size, and the high-risk group C had only uncemented, metalbacked cups, with the highest wear in the 32 mm head size. Less than 10 years of follow-up did not distinguish adequately between different designs of THR, except in a few cases which had early failures due to material or design deficiencies. Overall, the cemented all-polyethylene cup combined with the smaller ball head proved to be better.     

Correlation of wear debris-induced osteolysis and revision with volumetric wear-rates of polyethylene: a survey of 8 reports in the literature

This survey focused on clinical reports of polyethylene wear and osteolysis in total hip replacements. With regard to documentation of clinical wear-rates, 57 publications were reduced to an analysis of 8 reports of THR series, including the incidence of osteolysis. A direct correlation was found among volumetric wear-rates, incidence of osteolysis and revision rates in THR concepts of the 1983-1987 era. As volumetric wear rate increased, the incidence of osteolysis and revision rates increased. With regard to our grading system for volumetric wear, with follow-up in the 4-15 year range, osteolysis was rare in group A (wear = 0-80 mm3/year), ranging from 6% to 31% in group B (wear 40-80 mm3/year) and from 21% to 100% in group C (wear > 140 mm3/year). With regard to cup design, the optimal low-wear group had mainly cemented polyethylene cups with 22 and 28 mm head sizes. The mid-wear group B had metal-backed cemented and uncemented cups, with 28 mm head size, and the high-risk group C had only uncemented, metal-backed cups, with the highest wear in the 32 mm head size. Less than 10 years of follow-up did not distinguish adequately between different designs of THR, except in a few cases which had early failures due to material or design deficiencies. Overall, the cemented all-polyethylene cup combined with the smaller ball head proved to be better.