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.     

Migration analysis of cemented Müller polyethylene acetabular cups versus cement-free Zweymüller screw-attached acetabular cups

OBJECTIVE: Is the cementless Zweymüller hip cup superior to the cemented Müller cup? METHOD: This article presents a radiographic analysis of 25 cemented Müller acetabular cups versus 22 cementless Zweymüller cups using the Einbildr?ntgenanalyse (EBRA), a software tool for radiographic measurement of acetabular cup migration. In addition, we determined the effects of the cup anteversion and inclination, the polyethylene wear, the lateral bone coverage of the acetabular cup, the position of the center of rotation, and individual factors on the incidence of cup migration. RESULTS: The incidence of cup migration was 64% in the cementless group and 48% in the cemented group after a mean follow-up of 6 years. The average migration rate was 0.33 mm/a for cementless Zweymüller cups and 0.38 mm/a for cemented Müller cups. Cup anteversion and inclination showed no effect on the incidence of cup migration. The combination metal-polyethylene (0.17 mm per year) demonstrated a significantly higher wear rate in comparison to the ceramic-polyethylene combination (0.11 mm per year). Incompletely lateral covered cups demonstrated a significantly higher incidence of cup migration. Cranial or medial deviations of the center of rotation up to 5 mm are tolerable, in contrast to caudal or lateral deviations that lead to a significantly higher incidence of cup migration. CONCLUSION: The superiority of the cementless Zweymüller cup was not observed. We recommend a complete lateral bone coverage of the hip cup. Cranial and medial deviations of the center of rotation up to 5 mm are tolerable. In the present study the polyethylene wear of the ceramic-polyethylene combination was significantly less as compared with the metal-polyethylene combination.     

13-Jahres-Ergebnisse der CLS-Spreizpfanne in der primären Hüftendoprothetik

BACKGROUND: Clinical studies of the CLS expansion cup in hybrid hip arthroplasty generally show good results. However, follow-up times are limited to between 5 and 10 years. The aim of our study was to assess the clinical and radiological outcome of the CLS cup after more than 10 years. MATERIAL AND METHOD: After a follow-up of 13 years (10-15 years), 41 of 186 patients with a total of 41 CLS cups were available for clinical and radiological evaluation. In addition, a digital analysis of all radiographs was done. This included measurement of the migration, inclination, polyethylene wear, shaft subsidence, and osteolytic lesions. RESULTS: The average preoperative Harris hip score was 48, which increased to 81 at final follow-up. No acetabular loosening was found. Two cups (5%) showed osteolytic lesions not exceeding 50% of the specific zone according to DeLee and Charnley and were considered stable. There was no migration or inclination of the cups. The average polyethylene wear corresponded to 0.1 mm/year. Sixteen patients (39%) showed osteolyses around the stem and were considered loose. CONCLUSION: The CLS expansion cup provides excellent clinical results after 13 years in hybrid total hip arthroplasty. Time-correlative polyethylene wear and the extremely high rate of stem loosening have no consequences for the cup stability in our patient group. Acetabular osteolysis is rare.     

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.     

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.     

Failure of polyethylene acetabular cups. Two case reports

Fatigue fracture involving the metallic femoral stem is well recognized after total hip arthroplasty. Two cases of Charnley-Mueller polyethylene acetabular cup failure, in a 54-year-old-woman and a 77-year-old woman with abnormal wear patterns, were diagnosed prior to operation. The fracture of the acetabular cup was recognized by the fragmented, crushed appearance of the cup. The arthrogram clearly showed the radiographic contrast agent passing through the substance of the cup. The wear of the cups was measured by micrometer calipers which have an accuracy of 0.001 mm. The polyethylene acetabular cup was analyzed in four zones formed by three circumferential grooves. Markedly increased wear of the components occurred in the superolateral dome area. This wear rate was as high as 0.8 mm/year, which is four times the average wear of 0.2 mm/year. This marked wear associated with repetitive cyclic fatigue or static load resulted in fracture of the polyethylene acetabular cup. Improper machining of the cup using low- rather than high-density polyethylene in the manufacturing process and the heavy weight of these patients may have been factors in the marked fissures and crack lines revealed by microscopic study of the fractured area after sputter coating with gold palladium. Fracture of the polyethylene acetabular component, although rare, may be encountered more often in longer follow-up studies of patients who have undergone total hip arthroplasty. Proper selection of patients, acetabular spacers, and pressure injection techniques may prevent early loosening of the acetabular polyethylene components.     

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.     

Long-term results with cementless Fitek (or Fitmore) cups

Fitek cementless cups have been adopted in our department in 1989. The first 100 consecutive Fitek implants were analyzed clinically (Harris hip score) and radiographically (anteroposterior and lateral x-rays) with a mean follow-up of 9.7 years. We did not have any case of cup loosening or any other problem requiring cup revision. In this series, we had 86 excellent, 10 good, 2 fair, and 2 poor results. The 2 poor results were because of 2 cases of aseptic loosening of the stem (1 cemented and 1 cementless). The x-rays showed an average angle of cup inclination of 36.5 degrees (range 16 degrees -54 degrees ) after surgery and no variations at the last follow-up. Bidimensional linear wear of the acetabular component showed 6 cases of measurable wear with an average wear rate per year of 0.265 mm. The overall wear rate per year was 0.02 mm. At the time of the last follow-up examination, we had 3 femoral osteolysis and no case of acetabular osteolysis. In our series, we observed "lack of contact" zones above the polar depression in 71 cases immediately after surgery. The average thickness of these lines was 1 (range 0.5-3.5) mm. Of these, at the last follow-up, 61 cases (86%) showed a complete "filling" of the "lack of contact," whereas in 10 (24%), the "filling" was incomplete (4 cases still showing a radiolucent line [相似文献   

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.     

Ten-year results of ALIZE acetabular cup with hydroxyapatite coating and AURA hydroxyapatite-coated stem in total hip arthroplasty

One hundred seven total hip arthroplasties were done between 1991 and 1992 with ALIZE acetabular cup with hydroxyapatite coating (Biomet France, Valence, France) and AURA hydroxyapatite-coated stem (Biomet France) in 107 patients. The articulation was ceramic on polyethylene for 102 patients and metal on polyethylene for the remaining 5 patients. The mean follow-up of the series was 8.4 +/- 2.5 years. The mean preoperative Merle d'Aubigné hip functional score was 10.6 +/- 3 vs 15.8 +/- 1.8 at the latest follow-up. Sixty-three patients were alive for the long-term follow-up at a mean of 9.67 +/- 0.25 years. Of the patients, 98.5% were satisfied or very satisfied at the latest follow-up. Five revisions were documented in these series: 1 for acetabular loosening, 2 for traumatic ceramic head fracture, 1 for polyethylene replacement, and 1 for stem replacement due to bone fracture. The mean wear rate was 0.076 +/- 0.043 mm/y (<0.1 mm/y considered as the normal wear rate). The overall survival rate at 10 years was 95.6% +/- 2.1% using revision of either component as the end point.     

Acute total hip arthroplasty for selected displaced acetabular fractures: two to twelve-year results.

BACKGROUND: We assessed the role of acute total hip arthroplasty in a selected group of patients with a displaced acetabular fracture and complicating features that greatly diminished the likelihood of a favorable outcome after open reduction and internal fixation. METHODS: Between 1985 and 1997, fifty-seven patients underwent an acute total hip arthroplasty for a displaced acetabular fracture. Patients were followed for a mean of 8.1 years (range, two to twelve years). The mean time from the injury to the arthroplasty was six days (range, one to twenty days). The mean age of the patients at the time of the arthroplasty was sixty-nine years (range, twenty-six to eighty-nine years). Indications for the acute arthroplasty included intra-articular comminution as well as full-thickness abrasive loss of the articular cartilage, impaction of the femoral head, and impaction of the acetabulum that involved >40% of the joint surface and included the weight-bearing region. RESULTS: At the time of the latest follow-up, the mean Harris hip score was 89 points (range, 69 to 100 points); forty-five patients (79%) had an excellent or good outcome. There were six cases of heterotopic bone formation, including one of symptomatic grade-IV ossification. During the initial six postoperative weeks, the acetabular cups subsided an average of 3 mm medially and 2 mm vertically. All of the cups then stabilized, and none were loose at the latest follow-up evaluation. Six patients had excessive medialization of the cup, but none had late loosening or osteolysis. Nine cups (16%) had notable polyethylene wear, but none were revised. No cup or stem had late clinical or radiographic evidence of loosening. There were three late procedures: one for revision of a malaligned cup because of recurrent dislocations, one for removal of hardware from the greater trochanter, and one for excision of heterotopic bone. CONCLUSIONS: In selected patients with a displaced acetabular fracture that has a low likelihood of a favorable outcome after fracture treatment, an acute total hip arthroplasty may provide an alternative means with which to achieve a painless, mobile hip. These complex procedures are best undertaken by a surgical team with substantial experience with both acetabular trauma and hip arthroplasty.     

Medium-term results of the ABG total hip arthroplasty in young patients

A total of 66 patients (71 hips) <65 years old (average age, 55.4 years; range, 26-65 years) received a proximally hydroxyapatite-coated femoral prosthesis with a hemispheric metal-backed, hydroxyapatite-coated acetabular cup (ABG hip, Howmedica International, Staines, UK), with an average follow-up of 4.8 years (range, 2-7 years). All operations were performed by 1 surgeon in a district general hospital. The average preoperative Harris hip score and Merle d'Aubigné score were 59.8 and 9.6, which rose to 92.7 and 16.3 at the longest follow-up. Most patients were satisfied with the outcome, with only 2 patients complaining of intermittent thigh pain. Survivorship analysis predicted a survival rate of 96.87% at 7 years. There were 2 revisions, one to reposition an acetabular cup and one for an undersized femoral component. Radiographic changes were consistent with bone remodeling. There were no radiolucencies around the acetabular cup, but we noted eccentric polyethylene wear in 37 (60%) inserts ranging from 0.4 to 4 mm (annual wear average, 0.25 mm/y; range, 0.063-0.76 mm/y). There were no loose femoral stems. Osseointegration was achieved in all cases, with only 1 case developing endosteal cavitation in Gruen zone 2. Cancellous densification was found to be mainly in zones 2 and 6 (67.2% and 55.7%), extending distally in zones 3 and 5 (52.4% and 50.8%). Hypertrophy of the femoral shaft was less prominent and was noted mostly distally, in zones 3, 4, and 5 (11.4%, 18.3%, and 18.3%), extending proximally in zones 2 and 6 (8.1% and 13.1%). The ABG hip can achieve excellent results in the medium term, but polyethylene wear of the acetabular insert should be noted with concern.     

Mechanism of failure in hips with an uncemented, all polyethylene socket.

The outcome of 32 patients with 33 primary total hip replacements performed using noncemented uncoated polyethylene acetabular cups (RM cup) with cemented titanium alloy monoblock stems (STH-2 stem) was reviewed. At a mean followup of 6.3 years (range, 6 months-10 years), the failure rate was 57%, more than 14 times higher than the rate typically seen with cemented polyethylene acetabular cups used with the STH stem. Failure was characterized by rapidly progressive acetabular or femoral osteolytic lesions that resulted in extensive bone loss, often in patients who had no symptoms. In addition to the debris that typically is generated by a metal on plastic bearing couple, an abundance of polyethylene particles of submicron size were produced at the cup-bone interface. Tissues retrieved from areas of osteolysis revealed the presence of intracellular submicron polyethylene particles in macrophages. It is recommended that patients with no symptoms who have RM noncemented, uncoated acetabular cups be followed up yearly and undergo early revision surgery when faced with osteolysis to prevent extensive bone loss.     

Osteoblastic response to osteoarthrosis of the hip does not predict outcome of cementless cup fixation: 79 patients followed for 5-11 years

We evaluated the influence of osteoblastic response to osteoarthrosis of the hip on the outcome of cementless acetabular cup after 91 total hip replacements in 79 patients. Of the 91 hips, 23 were atrophic, 37 normotrophic, and 31 hypertrophic, according to Bombelli's criteria. There were no clinical or radiographic differences among the three groups at the final follow-up (average 7 (5-11) years), when stable bone growth had been achieved by all of the acetabular cups in patients with the atrophic type, 35/37 of the normotrophic type, and all the hypertrophic type. Revision of the acetabular cup was performed on 1 hip of the normotrophic type, in connection with severe polyethylene liner wear and progressive osteolysis.     

Early and late loosening of the acetabular cup after low-friction arthroplasty.

Between 1971 and 1979, 680 low-friction arthroplasties of the hip were performed in 598 patients. The average duration of follow-up was twelve years and eight months. Sixty-one acetabular cups had loosening as seen on roentgenograms eighteen years postoperatively, resulting in a total cumulative probability of loosening of 19 per cent, according to survivorship analysis. In twenty-nine cups, the loosening appeared within ten years after the operation (early loosening) and in thirty-two, more than ten years after the operation (late loosening). Early loosening was associated with deficient structure of the bone of the acetabulum, a previous congenital dislocation of the hip, acetabular fracture, or acetabular protrusion in all instances (p < 0.01). Late loosening was associated with the depth of acetabular wear. Of the thirty-two cups that had more than two millimeters of wear, eighteen (56 per cent) had loosening on the roentgenograms (p < 0.001). In hips that had early loosening, migration was the most frequent finding, and its rate of progression was higher than in hips that had late loosening (p < 0.001). In late loosening, a complete bone-cement radiolucency of more than two millimeters was the most frequent finding. Clinical failure was seen in twenty-two (76 per cent) of the twenty-nine cups that loosened early and in nine (28 per cent) of the thirty-two cups that loosened late. The probability of extensive resorption of bone necessitates close observation of patients who have early loosening, while a reasonable period of observation is possible for those who have late loosening.     

The ABG hydroxyapatite-coated hip prosthesis: one hundred consecutive operations with average 6-year follow-up

One hundred consecutive ABG (Anatomique Benoist Giraud, Howmedica) hydroxyapatite-coated hip arthroplasties in 97 patients were evaluated prospectively with a follow-up time of 4 to 10 years (mean, 6 years). Clinical results were excellent with an improvement in the Merle d'Aubigne score from 9 preoperatively to 17.4 at 5 years. Thigh pain was persistent in only 3%; it was mild in nature and controlled with simple analgesics. Kaplan-Meyer survivorship analysis was 100% for the femoral stem and 95% for the acetabular cup at 6 years. Of concern was the high polyethylene wear measured with an average of 0.24 mm/y (range, 0.05-0.76 mm/y).     

Osteoblastic response to osteoarthrosis of the hip does not predict outcome of cementless cup fixation: 79 patients followed for 5-11 years

We evaluated the influence of osteoblastic response to osteoarthrosis of the hip on the outcome of cementless acetabular cup after 91 total hip replacements in 79 patients. Of the 91 hips, 23 were atrophic, 37 normotrophic, and 31 hypertrophic, according to Bombelli's criteria. There were no clinical or radiographic differences among the three groups at the final follow-up (average 7 (5-11) years), when stable bone growth had been achieved by all of the acetabular cups in patients with the atrophic type, 35/37 of the normotrophic type, and all the hypertrophic type. Revision of the acetabular cup was performed on 1 hip of the normotrophic type, in connection with severe polyethylene liner wear and progressive osteolysis.     

Polyethylene wear in prosthetic hips with loose components

We measured in vivo polyethylene wear of acetabular cups in 74 patients (83 hips) with Charnley total hip arthroplasties (THA), revised because of aseptic loosening of either the acetabular or femoral component. We analyzed conventional pelvic radiographs of 42 THAs before revision due to loose acetabular components alone and 41 THAs before revision due to loose femoral components alone. The THAs were revised after 10 to 26 years. The mean wear-rate in hips with a loose acetabular components was 0.3 mm/y, whereas in hips with a loose femoral components, it was 0.1 mm/y (P=.0001). The mean total linear wear, as measured on the last available radiographs before revision, was 3.4 mm and 1.5 mm, respectively (P=.0001). A significant difference in linear wear between hips with loose cups and loose stems was seen 1 year after surgery: 0.4 mm/y versus 0.3 mm/y, respectively (P=.05).     

A comparison of polyethylene wear rates between cemented and cementless cups. A prospective, randomised trial

We selected randomly a consecutive series of 162 patients requiring hip replacement to receive either a cementless, hemispherical, modular, titanium acetabular cup or a cemented, all-polyethylene cup. These replacements were performed by two surgeons in four general hospitals. The same surgical technique was used and a 26 mm metal-head femoral component was used in every case. After exclusions, 115 hips were studied for differences in rates of wear and osteolysis. The mean clinical follow-up was eight years and the mean radiological follow-up, 6.5 years. The cementless cups wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year. This difference was significant (p < 0.0001). Our findings in this mid-term study suggest that cementless cups wear more than cemented cups.     

Long-term results of aseptic cemented Charnley revisions

One hundred eighty low-friction arthroplasties of the hip in 164 patients in first-time revision surgery were operated between 1973 and 1985. This series used only cement fixation, and aseptic loosening and femoral stem fractures were the only indications for revision. The average follow-up period was 11.5 years. Intraoperative and postoperative complications were frequent: femoral shaft fracture (13 cases), femoral shaft perforation (12 cases), deep infection (14 cases), and dislocation (15 cases). Twenty-eight hips were rerevised or removed (resulting in a total cumulative probability of rerevision of 20% after 16 years, according to survivorship analysis). Nineteen cups were rerevised (13% after 16 years, according to survivorship analysis), and 24 femoral stems were rerevised (16% after 16 years, according to survivorship analysis). Radiographic cup and femoral loosening appeared in 29 and 36 cases, respectively (24 and 22% after 16 years, respectively, according to survivorship analysis). Good results were observed when there was a healthy and intact bone bed, whereas poor results were related to inadequate bone stock in the acetabulum and femur. Radiolucent lines were frequent in both components; radiolucent lines less than 2 mm wide were frequent in acetabular zone 1. Pistoning of the prosthesis and the cement within the bone and calcar pivot was the most frequent type of stem loosening.