10-year results of the uncemented Allofit press-fit cup in young patients

Background and purpose — Uncemented acetabular components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the second decade in young and active patients. We report on a minimum 10-year follow-up of an uncemented press-fit acetabular component that is still in clinical use.

Methods — We examined the clinical and radiographic results of our first 121 consecutive cementless THAs using a cementless, grit-blasted, non-porous, titanium alloy press-fit cup (Allofit; Zimmer Inc., Warsaw, IN) without additional screw fixation in 116 patients. Mean age at surgery was 51 (21–60) years. Mean time of follow-up evaluation was 11 (10–12) years.

Results — At final follow-up, 8 patients had died (8 hips), and 1 patient (1 hip) was lost to follow-up. 3 hips in 3 patients had undergone acetabular revision, 2 for deep infection and 1 for aseptic acetabular loosening. There were no impending revisions at the most recent follow-up. We did not detect periacetabular osteolysis or loosening on plain radiographs in those hips that were evaluated radiographically (n = 90; 83% of the hips available at a minimum of 10 years). Kaplan-Meier survival analysis using revision of the acetabular component for any reason (including isolated inlay revisions) as endpoint estimated the 11-year survival rate at 98% (95% CI: 92–99).

Interpretation — Uncemented acetabular fixation using the Allofit press-fit cup without additional screws was excellent into early in the second decade in this young and active patient cohort. The rate of complications related to the liner and to osteolysis was low.     

Porous-ingrowth revision acetabular implants secured with peripheral screws. A minimum twelve-year follow-up

BACKGROUND: During revision total hip arthroplasty, the acetabular component is often secured with screws to ensure initial press-fit stability. The purpose of the present study was to assess a series of acetabular revisions involving the use of a porous-coated acetabular component that was stabilized with peripheral screws and to evaluate the results in relation to the acetabular bone deficiencies that were present at the time of the revision procedure. METHODS: From 1987 to 1991, 203 consecutive acetabular revisions were performed. In 142 hips, a severe acetabular bone deficiency that did not require an allograft was reconstructed with a porous-coated acetabular cup that was secured with a minimum of two peripheral screws. After an average duration of follow-up of 13.2 years, 134 hips were reviewed clinically and radiographically. The procedure was considered to be a clinical failure if the component was revised or if the postoperative clinical scores were poorer than the preoperative scores. RESULTS: At the time of the most recent follow-up, 127 (95%) of the 134 hips were stable and clinically successful. The other seven hips (5%) were considered to have failed. Five of these seven hips failed because of an infection, and two failed because of aseptic loosening. Five (19%) of the twenty-seven hips with a Paprosky type-3A defect (a defect in which 30% to 50% of the host acetabulum is missing) failed. CONCLUSIONS: Revision total hip arthroplasty with use of a porous-coated acetabular component that is fixed with peripheral screws can provide long-term durability in hips with severe acetabular defects that do not require the use of an allograft (Paprosky type-1 and type-2 defects). We recommend that when an acetabular implant with peripheral screws is used for the treatment of a more severe (type-3) defect, the cup should be augmented with structural allograft to improve initial stability, or other implants should be utilized.     

Acetabular revision without cement

We reviewed the clinical and radiologic results of 47 cementless acetabular revisions performed by a single surgeon. The mean follow-up period was 58 months. The American Academy of Orthopaedic Surgeons (AAOS) acetabular defect classification was type I in 4 hips, type II in 9 hips, and type III in 32 hips. All patients received AML (Depuy, Warsaw, IN) Duraloc cup implants. Morcellized allograft was used in 23 hips (49%), and screw augmentation in 22 hips (47%). The Harris Hip score improved from 72 to 90 points. No revisions were performed for aseptic loosening. Nonprogressive thin radiolucent lines were found in a single zone in 10 hips (21%) and in all 3 zones in 5 hips (11%). No migration was found in any cups with radiolucent lines, and the presence of a radiolucent line was considered clinically unimportant. Progressive loosening with migration of the cup was found in 1 hip (2%). Kaplan-Meier survivorship using revision for aseptic loosening or radiologic loosening as end points was 92% at 72 months. No statistically significant difference was found in the survival of the cups fixed with or without screws. These encouraging midterm results confirm the role of cementless acetabular revision.     

10-year results of the uncemented Allofit press-fit cup in young patients: 121 hips followed for 10–12 years

Background and purpose

Uncemented acetabular components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the second decade in young and active patients. We report on a minimum 10-year follow-up of an uncemented press-fit acetabular component that is still in clinical use.

Methods

We examined the clinical and radiographic results of our first 121 consecutive cementless THAs using a cementless, grit-blasted, non-porous, titanium alloy press-fit cup (Allofit; Zimmer Inc., Warsaw, IN) without additional screw fixation in 116 patients. Mean age at surgery was 51 (21–60) years. Mean time of follow-up evaluation was 11 (10–12) years.

Results

At final follow-up, 8 patients had died (8 hips), and 1 patient (1 hip) was lost to follow-up. 3 hips in 3 patients had undergone acetabular revision, 2 for deep infection and 1 for aseptic acetabular loosening. There were no impending revisions at the most recent follow-up. We did not detect periacetabular osteolysis or loosening on plain radiographs in those hips that were evaluated radiographically (n = 90; 83% of the hips available at a minimum of 10 years). Kaplan-Meier survival analysis using revision of the acetabular component for any reason (including isolated inlay revisions) as endpoint estimated the 11-year survival rate at 98% (95% CI: 92–99).

Interpretation

Uncemented acetabular fixation using the Allofit press-fit cup without additional screws was excellent into early in the second decade in this young and active patient cohort. The rate of complications related to the liner and to osteolysis was low.Uncemented acetabular components are widely used all over the world. A variety of these components have been associated with excellent short- to medium-term clinical and radiographic outcomes (Hallan et al. 2010, Howard et al. 2011). During the second decade of use, a number of cementless cup designs have shown durable fixation, but problems related to wear and osteolysis often compromise the results, and the surgeon can face serious problems in revision surgery because of extensive bone loss. This is a particular problem with young and active patients (Kim et al. 2012). Currently, there are few reports on the survival of contemporary uncemented cups that are still in clinical use in young patient cohorts with a minimum of 10 years of follow-up (Akbar et al. 2009, Kim et al. 2012), despite being used frequently in this group of patients.We evaluated the ten- or more-year results of an independent series of the non-porous, uncemented, press-fit Allofit cup in young patients (≤ 60 years old) implanted without any additional fixation (screws) and compared the results with those reported in the literature.     

Factors influencing the longer-term survival of uncemented acetabular components used in total hip revisions

BACKGROUND: There are few longer-term follow-up reports of the results and complications of the use of cementless acetabular components in revision hip arthroplasty. In this study, we analyzed the clinical and radiographic results to determine the factors that affect longer-term survival of titanium-fiber-metal-coated acetabular components. METHODS: During a fourteen-year period, one surgeon performed 211 consecutive unselected cementless acetabular revisions in 194 patients with a mean age of sixty-two years. The same technique was used for all revisions: the component was impacted and was fixed with multiple screws, and bone deficiencies were augmented with supplemental bone graft. Both the acetabular and the femoral components were revised in 142 hips, whereas an isolated acetabular revision was performed in sixty-nine hips. All 211 revisions were included in a survivorship analysis to twelve years. Prospectively determined clinical results in 135 hips and radiographic results in 131 hips were available at a minimum of five years postoperatively. RESULTS: Seven acetabular components were removed: three, because of infection; one, because of recurrent dislocation; and three, because of mechanical loosening. There was asymptomatic radiographic loosening of one additional acetabular component, for a total rate of aseptic loosening of 2%. The twelve-year prosthetic survival rate was 95% (95% confidence interval, 91% to 99%), with failure defined as component removal for any reason. There was no significant difference in the rate of survival of the cup or femoral component between the sixty-nine hips treated with isolated acetabular revision and the 142 hips in which both components were revised. There was a significant difference in the rate of dislocation between the hips treated with isolated acetabular revision (dislocation in fourteen hips, 20%) and those in which both components had been revised (dislocation in eleven hips, 8%; p = 0.03), but there was no difference in component survival if a dislocation occurred. There was a significant association between a patient weight of >82 kg and acetabular failure (p = 0.04). CONCLUSIONS: This titanium-fiber-metal-coated hemispheric component fixed with multiple screws had a twelve-year survival rate of 95% when used in an unselected, consecutive series of acetabular revisions. The rate of dislocation was significantly higher in the patients treated with isolated acetabular revision, and routine postoperative bracing is now recommended for that group.     

Extra-large press-fit cups without screws for acetabular revision

This retrospective study reports the 4- to 6-year results of clinical and radiologic follow-up of 60 acetabular revisions using extra-large hemispherical press-fit cups without additional screw fixation. Bone grafts were used in 17 cases. One cup loosened and required re-revision after 12 months. Initial migration was noted in 6 cases, but showed no progression after less than 2 years. In 2 hips that were revised for deep infection, the cups were found incorporated. At final follow-up, 57 hips (95%) were found firmly fixed radiologically. The Harris Hip score improved from a mean of 58.7 points preoperatively to 90.6 points. Provided a high friction coefficient is present, extra-large hemispherical cups offer sufficient stability even in severe cases. Most do not require additional screw fixation.     

Alumina-on-alumina total hip prostheses in patients 40 years of age or younger

To avoid the consequences of polyethylene wear in a high-risk population, 128 alumina-on-alumina total hip arthroplasties have been done in 104 consecutive patients. The maximum age of patients was 40 years. The main preoperative diagnoses were osteonecrosis and sequellae of congenital hip dislocation (71% of the hips). The same titanium alloy cemented stem was implanted in all of the hips. Four types of alumina acetabular component fixations were used: a cemented plain alumina socket (41 hips), a screw-in ring with an alumina insert (22 hips), a press-fit plain alumina socket (32 hips), and a press-fit titanium metal back with an alumina insert (33 hips). Eight patients (11 hips) died during the followup period. Sixteen revisions have been documented, 12 for acetabular aseptic loosening, three for bipolar loosening (two of which were septic), and one for unexplained pain. Eighty-eight hips in 74 patients have been followed up radiologically for 2 to 22 years. Wear was unmeasurable. Four additional sockets showed definite migration. The respective survival rates after 7 years were 94.1% for the cemented cup, 88.8% for the screw-in ring, 95.1% for cementless press-fit plain alumina socket and 94.3% for the metal-back press-fit component. The 10-year survival rate was 90.4% for the cemented socket and 88.8% for the screw-in ring. The 15-year survival rate was 78.9% for the cemented socket. Grafting was the only prognostic factor, with a survival rate of 62.6% after 10 years for the hips with a bone graft and of 90.1% for hips without a graft. The alumina-on-alumina bearing surfaces seem to be a valuable alternative to the standard metal-on-polyethylene system for young patients. However, an improvement in socket fixation is required to lengthen the life span of the prosthesis to match the life expectancy of this demanding population.     

Effect of augmented cup fixation on stability, wear, and osteolysis: a 5-year follow-up of total hip arthroplasty with RSA

To evaluate different modes of cementless fixation of hemispherical cups, we operated on 87 hips in 81 patients using 4 different means of cup fixation. The hips were randomly assigned to fixation with press-fit technique only (PF), or with augmentation with screws (S), pegs (P), or hydroxyapatite (HA) coating. The patients were evaluated with radiostereometric analysis (RSA) for cup migration and wear, conventional radiography for osteolysis, and Harris Hip Score for clinical outcome over 5 years. The fixation of the cups did not differ between the groups, but HA showed a tendency to decrease proximal migration. HA-coated cups displayed the best interface with hardly any signs of radiolucent lines, indicating a superior sealing effect of the HA coating. Cups with screws or pegs had more radiolucent lines and osteolytic lesions than the other groups. Radiolucent lines were correlated to higher proximal migration, young age, and female gender (r2=.2). The wear rate of the ethylene oxide-sterilized polyethylene liner was high (0.2 mm/y) but did not differ between the groups. Two cups with a perioperative fracture of the acetabular rim showed large initial migration but stabilized thereafter.     

人工全髋关节翻修术中骨缺损的处理

目的研究全髋关节翻修术中骨缺损的处理方法。方法1990年12月至1999年6月对16例一期行金属-聚乙烯假体全髋关节置换术失败患者行全髋关节翻修术。处理髋臼骨缺损的方式包括：（1）髂骨填充骨缺损（3例）,（2）骨水泥填充骨缺损（5例）,（3）异体颗粒骨打压植骨结合金属网重建髋臼（8例）,后两种方式均属骨水泥型。16例行全髋关节翻修术患者全部行髋臼翻修,其中10例同时行股骨柄翻修。所有患者均进行临床和影像学随访。结果所有患者均获得随访,随访时间4．1～7．7年,平均5．9年。Harris评分由全髋关节翻修术前的范围,62-75分,平均68分,升至术后的90—94分,平均91分。随访中均未出现假体旁透亮线、假臼杯水平或垂直移位和骨溶解等征象。共有4例出现并发症,包括异位骨化2例,脱位2例,无一例发生感染。结论有效修复髋臼骨缺损,进行髋部骨性结构的重建,是全髋关节翻修术成败的关键。     

Intermediate clinical follow-up of a dual-radius acetabular component

In this study, 92 primary total hip arthroplasties were performed in 83 patients using a porous-coated, dual-radius, cementless, acetabular component. All hips underwent line-to-line dome reaming with press-fit implantation that was judged to have complete bone contact. This acetabular shell provides a 1-mm oversized peripheral rim, which adds excellent initial stability while allowing complete bone contact in all hips. No fractures occurred. In 83% of hips, adjunctive screw fixation was not necessary. At a minimum of 4 years, follow-up, there were no revisions, no acetabular migration, one case of acetabular erosion consistent with osteolysis, and the average Harris Hip Score was 95. The design features of this new acetabular component have provided excellent fixation with complete initial bone contact, resulting in satisfactory intermediate clinical and radiographic results. The design provides excellent peripheral stability and complete bone contact.     

Isolated revision acetabuloplasty using a porous-coated cementless acetabular component without removal of a well-fixed femoral component: A 3- to 9-year follow-up study

The results of isolated acetabular revision performed in 31 patients (32 hips) were monitored for between 3 and 9 years. All femoral components were well fixed and not removed or revised at the time of index surgery. There were 4 hips with little or no acetabular bony defect, 2 hips with pure segmental defects (type I), 10 hips with cavitary defects (type II), 15 with combined segmental cavitary defects (type III), and 1 with pelvic discontinuity (type IV). All revision acetabular implants were cementless, using a porous-coated hemispheric cup with or without bone-graft. There were four grade I reconstructions, 16 grade II reconstructions, and 12 grade III reconstructions. At final follow-up evaluation 94% of the cups were judged to be stable. Two hips required a second revision acetabuloplasty because of loss of fixation of the cup. The 2 repeat revisions were also done without removal of the femoral component. One acetabular component had evidence of rotational migration, which stabilized and remained nonprogressive. There were no cases of femoral component radiographic or clinical failure. The mean pre and postoperative hip scores were 44 and 83, respectively. The pre- and postoperative pain scores were 12 and 42, respectively. The findings of this study suggest that isolated acetabular revision, using a cementless porous-coated hemispheric cup, can be successfully performed without removing or revising a well-fixed femoral stem and not compromise the final outcome.     

Cementless acetabular reconstruction in revision total hip arthroplasty

Reconstruction of the failed acetabular component in total hip arthroplasty (THA) can be challenging. Although there are multiple reconstructive options available, a cementless acetabular component inserted with screws has been shown to have good intermediate-term results and is the reconstructive method of choice for the majority of acetabular revisions. We reviewed the results of 138 consecutive acetabular revisions done with a hemispheric, cementless acetabular component that is sintered with Ti fiber metal mesh and was inserted with line-to-line reaming and multiple screws for fixation. At a mean of 15 years, 19 acetabular components had been revised (13.8%); seven were revised for recurrent instability, six were revised for deep periprosthetic infection, five well-fixed cups were removed at the time of femoral revision, and one cup was fixed by fibrous tissue only at the time of femoral revision and was removed. One acetabular component was radiographically loose. Survivorship of the component was 81% at 15 years when revision for any reason was considered as an end point and 96% when revision for loosening or radiographic evidence of loosening was considered as a second end point. Cementless acetabular revision provides durable results at 15 years with a low rate of failure for loosening.     

Stability of Revision Acetabular Components Using the Rim-Fit Technique

Use of the rim-fit technique in revision acetabular surgery was reviewed for 20 hips in 18 patients. Defects at revision surgery included isolated medial segmental and global cavitary deficiencies with largely intact peripheral rim. A cementless acetabular component is placed to achieve a press-fit against the bony acetabular rim after morselized allograft and/or autograft was placed behind the cup. The average follow-up period was 68.3 months (5.7 years) (range, 27-112 months). Cup migration was assessed using digital radiography. Average vertical migration was 1.02 mm superiorly, and average horizontal migration was 0.8 mm medially. The abduction angle changed on average by 0.25°. Use of the rim-fit technique for treatment of cavitary acetabular defects is associated with component stability and minimal component migration.     

Press-fit cementless acetabular fixation with and without screws

Purpose

Cementless acetabular fixation for total hip arthroplasty (THA) is widely used. The question of using screws for a better primary and secondary acetabular fixation has been discussed in the literature in recent years. The aim of this meta-analysis was to compare fixation of acetabular cups with and without screws in total hip arthroplasty.

Methods

Electronic databases Embase, PubMed and Cochrane Library were used to search for randomised controlled trials reported through May 2013 of cementless acetabular fixation for THA with and without screws. Two independent reviewers assessed the trials for eligibility and quality. All related data matching our standards were abstracted for meta-analysis by RevMan 5.0. Evaluation criteria included revisions, migration and osteolysis.

Results

A total of 1,130 THAs enrolled into five trials were included in this meta-analysis. All studies compared fixation of acetabular cups with and without screws, and our pooled data showed no statistical significance between the two surgical methods in revision, migration and osteolysis.

Conclusion

There is no significant difference between cementless acetabular fixation for THA with and without screws in revisions, migration or osteolysis.     

Cementless hemispheric porous-coated sockets implanted with press-fit technique without screws: average ten-year follow-up

BACKGROUND: Press-fit implantation of a porous-coated hemispheric acetabular component without screws is an option for primary total hip replacement. The purpose of the present study was to evaluate the results of this technique after an average duration of follow-up of ten years to determine if there was any loss of fixation or increase in osteolysis over time. METHODS: From June 1988 to November 1990, 132 primary total hip replacements were performed with a porous-coated socket that was implanted with use of a press-fit technique. Twenty-two hips were excluded because the patient had died or had been lost to follow-up, leaving 110 hips (103 patients) available for inclusion in the study after an average duration of follow-up of 10.2 +/- 1.0 years. The average age of the patients at the time of operation was 60.7 years (range, 23.7 to 86.2 years). Radiographs were evaluated with regard to initial gaps, radiolucent lines, migration, polyethylene wear, and osteolysis. Kaplan-Meier survivorship analysis was performed to calculate the rate of survival of the acetabular component. RESULTS: One hip (0.9%) had revision of the socket because of aseptic loosening, and four hips (4%) had revision of a stable socket. With the numbers available, the presence of gaps on the initial postoperative radiographs was not associated with the occurrence of radiolucent lines (p = 0.039). Pelvic osteolysis was seen in four hips, with an average time to radiographic appearance of six years. Increased wear was directly related to an abduction angle of >40 degrees. The twelve-year survival rate was 99.1% with revision because of failure of fixation of the metal shell as the end point, 95.3% with revision for any reason as the end point, and 79.6% with exchange of the liner as the end point. CONCLUSIONS: The fixation of this press-fit socket did not deteriorate over time and was associated with a low rate of osteolysis. The most common reasons for reoperation were wear and dissociation of the polyethylene insert.     

Modular acetabular reconstructive cup in acetabular revision total hip arthroplasty at a minimum ten year follow-up

Purpose

Modular acetabular reconstructive cups have been introduced in an attempt to offer initial rigid fixation by iliac lag screws and ischial pegs, to support bone grafts with a flanged metal socket, and to restore original hip center in acetabular revision. The purpose of this study was to clarify minimum ten year follow-up results of this cup system with morsellised allografts in revision cases.

Methods

We retrospectively investigated 54 acetabular revisions at a mean of 11 years (range, ten to 14 years). The indications were Paprosky’s type 2B (eight hip), 2C (eight hips), 3A (23 hips), 3B (nine hips), and 4 (six hips).

Results

Using aseptic loosening as the endpoints, the survival rate was 89.3 % (95 % CI 81–98). Radiographically, one type 3A hip, three type 3B hips and one type 4 hip showed aseptic loosening while no type 2 hips or no cemented cups showed loosening.

Conclusions

The modular reconstructive cups for acetabular revision showed bone stock restoration and stable implantation.     

Locking versus standard screw fixation for acetabular cups: is there a difference?

Introduction

Total hip replacement has been established as a valid treatment option for displaced subcapital fractures. However, insufficient primary fixation may be the reason for early loosening in these osteoporotic patients. Primary fixation of the cup is usually achieved by press-fit fixation that can be enhanced using screws. Locking the screws into their respective cups may seem to improve the primary fixation of the construct, as locked plates proved superior fixation for osteoporotic fractures.

Methods

The study consisted of three groups: in each group, three cups were fixed into blocks of foam bone using press-fit technique. In the first group, no additional screws were used, in the second group two standard screws were inserted, while in the third group two acetabular screws were cemented into the cup to simulate locked screw fixation. Load was applied onto the rim of the acetabular component to cause shearing between the cup and the block. Cup fixation was examined by a loading machine that acquired load versus displacement. The stiffness (load vs. displacement) was calculated.

Results

Screws, either locked or non-locked, enhanced cup fixation by 26 % (p value <0.01). No significant changes were found between the locking and non-locking screws groups.

Discussion

These experimental results indicate that acetabular screws enhance primary cup fixation. This may become significant in conditions where the acetabular bone stock is suboptimal, such as when performing total hip arthroplasty after displaced subcapital fractures. However, there is no superiority for locked screws over standard screw fixation.     

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.     

Revision total hip arthroplasty using a cementless acetabular component: technique and results

One hundred thirty-eight acetabular revisions for aseptic loosening were performed in 132 patients using a cementless hemispherical component coated with titanium mesh and inserted with supplemental screw fixation. Twelve patients died, 9 were lost to follow-up and 6 could not return, leaving 111 patients (115 hips) at mean 100 months follow-up. Thirteen hips required revision (11%); 4 for recurrent dislocations, 6 for sepsis, and 3 stable cups were revised (at the time of stem revision). No cup was revised for aseptic loosening. Radiographic review was available for 105 patients (109 hips) at mean 98 month follow-up (78 to 135 months). One hundred cups (91%) were considered stable. Seven cups were possibly unstable (7%), one cup was probably unstable (1%), and one septic hip had an unstable cup (1%). Four percent of the cups showed a complete radiolucency. A partial progressive radiolucency was seen in 3%, a partial nonprogressive radiolucency in 54%, and no radiolucency was present in 39%. A screw radiolucency was seen in 2%, and osteolysis at the cup margin in 4%. Revision of the acetabulum with a cementless porous-coated hemispherical fiber-metal component seems to be superior to the results reported for acetabular revisions with cement at similar follow-up.