Isoelastic femoral component in primary cementless total hip arthroplasty

We followed 100 patients (111 hips) who underwent primary total hip arthroplasty between July 1988 and June 1995 using the isoelastic femoral component. The average age was 61 (30-70) years. Mean follow-up time was 8.4 (5-12) years. Three femoral components were revised for aseptic loosening and one for disabling thigh pain. Six additional femoral components were considered probably loose by the radiographic criteria. Osteolysis around the femoral component was noted in only two patients who were clinically asymptomatic. A high incidence (41%) of lateral migration of the tip of the femoral components was noted, but there was no significant distal migration. Nine patients complained of thigh pain, which interfered with their daily activities. The average Harris hip score improved from 49 to 80 at the latest follow-up. We believe that the principle of isoelasticity in hip replacement is important; however, improvements in the material and the design of the femoral component are required.     

Failure of cementless fixation of the femoral component in total hip arthroplasty.

The basic concepts involved in cementless fixation of the total hip arthroplasty femoral component have been controversial. Some clinicians advocate fixation only of the proximal portion of the stem so that weight-bearing loads will be transferred proximally, and proximal stress shielding will be avoided. Others advocate distal fixation to ensure rigidity of fixation but concede that it will lead to proximal stress shielding and bone loss. However, clinical evidence suggests that the design of the implant is one important factor in determining stress shielding. When the stem is smooth and cylindrical distally, proximal stress relief does not occur, even when the stem is fixed tightly distally. Because femoral component loosening is the most common clinical problem with cementless total hip arthroplasty, every effort should be made to achieve fixation of the implant. Proximal and distal fixation can be achieved with most of the available implants. For tight proximal fixation, a good proximal implant design and a precise line-to-line preparation technique are critical, but aggressive broaching and interference-fit techniques result in a high rate of proximal femoral fracture during preparation and implantation. When the conditions are good for excellent proximal fixation, a flexible stem should be selected to apply a large amount of stress proximally. The stress transferred through distal fixation will be small in this situation, and the reaming technique of the femoral diaphysis does not need to be very aggressive. Approximately 10 to 20 mm of tight distal fit combined with the 0.5-mm underreaming technique provides sufficient distal fixation, and the chance of distal femoral fracture during insertion of the stem is minimum with this technique. When conditions are unfavorable for excellent proximal fixation, such as in revision hip arthroplasty, or when a proximal deformity or osteoporosis is present, a relatively rigid stem should be selected to avoid overloading proximal fixation and, thus, generating large proximal micromotion. The stress transferred through distal fixation will be large in this situation, and a relatively aggressive but well-controlled reaming technique of the diaphysis is required. Approximately 20 to 40 mm of tight distal fit combined with a 0.5-mm underreaming technique is adequate to obtain sufficient distal fixation and still avoid distal femoral fracture. Implant design features that improve proximal fixation and instrumentation features that improve bone preparation and decrease the risk of failure will broaden the indications for cementless fixation. As fixation and instrumentation improve, more flexible implants can be developed to improve bone preservation and avoid proximal stress relief.(ABSTRACT TRUNCATED AT 400 WORDS)     

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…     

Current status of acetabular fixation in primary total hip arthroplasty.

Factors that influence the outcome of acetabular replacement are design materials, means of fixation, operative technique, and patient-related parameters (e.g., etiology of osteoarthrosis). Whereas improved cementing techniques have produced a marked reduction in the rate of femoral component loosening, the incidence of acetabular loosening has been only slightly influenced by such improvements. Presently, uncemented porous-coated acetabular components represent the state of the art in total hip arthroplasty. Experimental and clinical data have shown in histologic, radiologic, clinical, and survivorship studies that hemispheric cups are superior to other designs and that primary stability can be better maintained by creating "intrinsic" stability (e.g., "oversized cup") rather than by screw fixation. Threaded cups have failed to demonstrate any improvement in results and have been virtually abandoned in the United States. The idea of metal backing has some obvious theoretical advantages. However, metal backing has failed to provide any improvement with respect to cemented cups. There are great reservations concerning metal backing in cementless fixation. Although there is some enthusiasm about hydroxyapatite, a "wait-and-see" attitude is justified because of the brittleness of the material, its questionable strength of bonding to substrate, and its unproven long-term behavior in vivo. Polyethylene as a bearing surface remains problematic, and the future will show whether new technologies are able to solve the problems encountered with metal-to-metal combinations. For the size of the femoral head, a compromise between smaller (22 mm) and larger (32 mm) components seems to be most effective.     

Matched-pair analysis of cemented and cementless acetabular reconstruction in primary total hip arthroplasty

In a matched-pair study of primary total hip arthroplasty, 45 all-polyethylene cemented acetabular components were compared with 45 cementless, hemispheric, titanium acetabular components. At 9 to 12 years, 1 of the cemented acetabular components was revised for aseptic loosening, and 14 (31%) were radiographically loose. Nine (20%) cemented acetabular components had pelvic osteolysis. In the cementless acetabular component group, 2 well-fixed components were revised. No components were radiographically loose, and 3 (7%) had pelvic osteolysis. Thirty-eight (97%) of the patients in each group were satisfied with the surgery. The clinical results of the cemented and cementless components were excellent. The cementless components had less loosening (P <.001) than the cemented components.     

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.     

Total hip arthroplasty with the use of nonmodular cementless acetabular component

Sixty-seven hips in 63 patients who underwent total hip arthroplasties with the use of the nonmodular cementless acetabular component and alumina-on-polyethylene bearing surface were available for complete clinical and radiographic review at a mean follow-up period of 7 (range 5-9) years. The mean age was 59 years (range 34-75) years. The mean preoperative Harris hip score of 50 points improved to 93 points at final follow-up. One (1.5%) hip required revision for a recurrent dislocation. No component was loose radiographically at final follow-up. The mean linear wear rate was 0.07 (range 0.01-0.23) mm/y. At a mean follow-up of 7 years, there was no aseptic loosening. Further follow-up, however, is necessary to determine the potential advantage of nonmodular acetabular component for the development of pelvic osteolysis.     

Effect of screw fixation on acetabular component alignment change in total hip arthroplasty

Purpose

The use of screws can enhance immediate cup fixation, but the influence of screw insertion on cup position has not previously been measured. The purpose of this study was to quantitatively evaluate the effect of intra-operative screw fixation on acetabular component alignment that has been inserted with the use of a navigation system.

Methods

We used a navigation system to measure cup alignment at the time of press-fit and after screw fixation in 144 hips undergoing total hip arthroplasty. We also compared those findings with factors measured from postoperative radiographs.

Results

The mean intra-operative change of cup position was 1.78° for inclination and 1.81° for anteversion. The intra-operative change of anteversion correlated with the number of screws. The intra-operative change of inclination also correlated with medial hip centre.

Conclusion

The insertion of screws can induce changes in cup alignment, especially when multiple screws are used or if a more medial hip centre is required for rigid acetabular fixation.     

Clinical experience with primary cementless total hip arthroplasty.

One hundred-eleven patients (121 hips) treated with cementless total hip arthroplasty (Harris-Galante, Zimmer) were clinically and radiographically reviewed at an average follow-up of 67 months (55-79). 9,1% of the stems presented signs of loosening and 5 stems (4,1%) had to be revised. None of the acetabula required revision surgery for loosening. One socket was revised due to recurrent dislocation. Clinical results were evaluated according to Harris protocol: excellent 75,2%, good 12,4%, fair 5%, poor 3,3%. Ten (7,9%) intraoperative fractures of the proximal femur were observed: in 2 cases stem instability consequently occurred. Endosteal cortical erosions, not clinically evident, were observed in 8,3% of stable stems. A foreign body biological reaction to polyethylene or metallic debris is supposed as cause of erosions.     

The use of cementless expansion acetabular component and an alumina-polyethylene bearing in total hip arthroplasty for osteonecrosis

We performed 114 consecutive primary total hip arthroplasties with a cementless expansion acetabular component in 101 patients for advanced osteonecrosis of the femoral head. The mean age of the patients at surgery was 51 years (36 to 62) and the mean length of follow-up was 110 months (84 to 129). The mean pre-operative Harris hip score of 47 points improved to 93 points at final follow-up. The polyethylene liner was exchanged in two hips during this period and one broken acetabular component was revised. The mean linear wear rate of polyethylene was 0.07 mm/year and peri-acetabular osteolysis was seen in two hips (1.9%). Kaplan-Meier analysis indicated that the survival of the acetabular component without revision was 97.8% (95% confidence interval 0.956 to 1.000) at ten years. Our study has shown that the results of THA with a cementless expansion acetabular component and an alumina-polyethylene bearing surface are good.     

Three- to five-year results with the cementless Harris-Galante acetabular component used in hybrid total hip arthroplasty

Summary In this paper we present our 3- to 5-year results after hybrid total hip replacement using the cementless porous coated Harris-Galante acetabular component and the cemented Griss femoral component in 39 patients with 40 implantations. Postoperatively, mild to moderate pain was experienced by 16.1% of patients, mostly following hard activity. A slight to moderate limp occurred in 24.2%. All patients were able to walk more than 1000 m. Full-time use of support was required by 2.8%. The postoperative range of motion was increased in 93.9%. Radiographically, none of the acetabular or femoral components had to be classified as unstable. Only one acetabular component displayed complete (i.e., along all interface zones) radiolucency and was therefore classified as possibly unstable.     

Minimum 10-year radiographic follow-up of a cementless acetabular component for primary total hip arthroplasty with a bulk autograft

We radiographically investigated 36 hips in 34 patients with osteoarthritis of the hip who had undergone total hip arthroplasty. Their mean age was 59.2 years (range 36–79 years), and the mean follow-up period was 11.2 years (range 10–14 years). The long-term outcome and the chronological changes in the bulk autograft were examined. The acetabular component of the prosthesis was a Lord-type threaded cup with a smooth surface. At follow-up, bone absorption was minor in 17 joints, moderate in 11, and major in 8. The hips with graft coverage of 20% (group A) had a significantly higher loosening rate than hips with coverage of 20% (group B) (P 0.05). The cup position changed markedly in group A. Our findings indicate that graft coverage should be less than 20% when a bulk graft is used together with a smooth-surfaced cementless cup.     

Midterm results of 506 solid trispiked reflection cementless acetabular components for primary total hip arthroplasty

The purpose of this prospective study was to evaluate the outcomes and survivorship of a trispiked, sintered bead-coated titanium shell with a polished inner surface, no screw holes, and an improved locking mechanism. A total of 506 total hip arthroplasties with a minimum 5-year follow-up were available for review at a mean of 7 years (range, 5-11 years). Three sockets (0.6%) were revised for reasons other than aseptic loosening, and 14 (2.8%) polyethylene liners were exchanged. There was no difference in revision rate between non-cross-linked and highly cross-linked liners (P = .4). There were no cases of radiographic loosening. Retroacetabular osteolysis was identified in 2%. The overall 5-year and 10-year Kaplan-Meier survivorship was 97.5% and 97.4%, respectively, whereas survivorship of the shell was 99.8%.     

Fate of cementless acetabular components retained during revision total hip arthroplasty

BACKGROUND: Removal of a well-fixed cementless acetabular component can result in increased operative time and postoperative morbidity. The objectives of this retrospective study were to determine whether retention of a well-fixed acetabular component at the time of isolated femoral revision was compatible with long-term socket survival. METHODS: The records of eighty-three consecutive patients (ninety hips) in whom a well-fixed cementless socket had been retained during revision of a femoral component were reviewed. The mean age of the patients was 48.7 years at the time of the primary arthroplasty and 54.1 years at the time of femoral revision. The radiographic analysis was based on anteroposterior radiographs and was performed by a single independent reviewer. The intraoperative criterion for stability of the socket was the absence of movement at the bone-implant interface during the application of direct pressure to the edges of the socket in four quadrants with use of a metallic pusher. RESULTS: At the time of the isolated femoral revision, no socket demonstrated a radiolucent line measuring >1 mm in any two zones and forty of the ninety hips had periacetabular osteolysis. The mean size of the osteolytic lesions was 5.71 cm(2) (range, 0.4 to 24.2 cm(2)), and twenty-eight of the forty hips underwent bone-grafting. The mean duration of follow-up was 9.7 years after the isolated femoral revision and 14.9 years after the primary arthroplasty. Five acetabular sockets were revised at a mean of 6.8 years after the femoral revision. Only one of these sockets had failed because of aseptic loosening. With revision of the acetabular component for any reason as the end point, the survival rate was 98.7% at five years and 93.5% at ten years after the femoral revision and 100% at ten years and 93.9% at fifteen years after the primary arthroplasty. No hip showed recurrence or expansion of periacetabular osteolysis. The prevalence of dislocation was 16% (fourteen of ninety). CONCLUSIONS: Revision of a stable, cementless acetabular component solely on the basis of its duration in vivo or the presence of periacetabular osteolysis does not appear to be warranted. Retention of the socket with grafting of larger periacetabular osteolytic lesions appears to be consistent with satisfactory socket longevity.     

The effect of acetabular and femoral component version on dislocation in primary total hip arthroplasty

Purpose

The purpose of the present study was to: (1) investigate the variation of both acetabular and femoral component version in a large series of consecutive primary THA patients, and (2) to better define the associations of acetabular and femoral component alignment and clinical factors with subsequent hip dislocation in those patients.

Methods

We analyzed CT scans of 1,555 consecutive primary THAs and measured version of the components. We also documented the frequency and direction of subsequent dislocation as well as femoral head size, posterior tissue repair, any history of previous hip surgery, and gender.

Results

The dislocation rate after THA was 3.22 %. The dislocation risk was 1.9 times higher if cup anteversion was not between 10° and 30°. Compared to hips that did not dislocate, those that experienced anterior dislocation had a significantly greater combined anteversion; those that dislocated posteriorly had a significantly smaller combined anteversion. Hips with previous rotational acetabular osteotomy or head size smaller than 28 mm correlated with an increased dislocation rate.

Conclusion

The dislocation risk could be higher if cup anteversion was not between 10° and 30°. Greater combined anteversion could be a risk factor of anterior dislocation, and posterior dislocation could be more common in smaller combined anteversion.

     

The Bicontact cementless primary total hip arthroplasty: long-term results

We report on a prospective series of 201 primary uncemented total hip arthroplasties with a Bicontact prosthesis at a mean follow-up of 12.9 years. The mean Harris hip score improved from 41 before surgery to 89 at final follow-up. Two femoral stems, one each for infection and fracture, and 12 cups were revised. The mean number of years to revision post-primary surgery was 8.7 years (six months to 16 years). The cumulative survival of the prosthesis was 95.42% for any cause at ten years and 93.57% at 12 years. Survivorship for aseptic loosening of the femoral stem was 100%. In our series, the Bicontact uncemented total hip arthroplasty stem without hydroxyapatite coating showed excellent survival and the cup survival was comparable to other leading series.     

Poor results of the cementless total hip arthroplasty with a nonporous coated acetabular component: AcSys Shearer Cup

Background This study followed patients for a minimum of 7 years after primary total hip arthroplasty using cementless acetabular components and evaluated their outcomes. Methods We followed 73 patients (75 hips), who had undergone total hip arthroplasty with cementless nonporous coated acetabular components (3M AcSys Shearer Cup) for a mean of 9.8 years (range 7–13 years). There were 61 women and 12 men with a mean age of 53 years (range 27–69 years) at surgery. The diagnosis was primary osteoarthritis in 9 hips, osteoarthritis secondary to developmental dysplasia in 58 hips, osteonecrosis of the femoral head in 6 hips, and rheumatoid arthritis in 2 hips. Results Three cups were revised because of aseptic loosening, and one cup was revised following removal of the prosthesis due to deep infection. Radiographic loosening was observed in 22 hips at the latest follow-up. The survival rate at 10 years was 94.7% with revision as the endpoint and 72% with radiographic loosening as the endpoint. The Merle d'Aubigné and Postel hip score showed significant improvement postoperatively and was maintained well even in cases showing radiographic loosening. Conclusions The intermediate radiological results with the AcSys Shearer Cup were unsatisfactory because of the high loosening rate, although the revision rate was low. The nonporous outer surface and the poor fixation mechanism between the metal shell and liner may have contributed to the high failure rate. Regular radiological review is recommended when this cup is used because early loosening is often painless.     

Plasma spray-coated Ti femoral component for cementless total hip arthroplasty

A retrospective study of the clinical and radiographic results of Mallory Head total hip arthroplasties in 67 patients (76 hips) with a mean age of 50.1 years was undertaken. The mean follow-up period was 10.1 years (9-13years). In this study, excellent or good clinical results were found for 64 patients. Minimal thigh pain was found in 3 patients (4.4%). Seventy-one hips (93.4%) showed fixation by bony ingrowth and 3 (3.9%) showed stable fibrous fixation. Bony ongrowth and ingrowth were also seen in 16 hips (21%) at distal smooth and grit-blast areas. Two femoral components were revised (survival rate, 97.3%), one for subsidence and other for recurrent infection. We believe that these good results were caused by excellent bony ingrowth on the proximal two thirds of the femoral surface area. In conclusion, proximal plasma-spray coating and the tapered shape of the Ti stem showed excellent bony ingrowth and initial stability. Our results indicate that the tapered shape will be an important element in the design of a cementless Ti stem.