Reverse hybrid and cemented hip replacement compared using radiostereometry and dual-energy X-ray absorptiometry

Background and purpose Total hip replacement (THR) with a reverse hybrid (RH), a combination of a cemented polyethylene cup and a cementless femoral stem, has been increasingly used in Scandinavia. In a randomized trial, we compared an RH THR with a proximal hydroxyapatite- (HA-) coated stem to a conventional cemented THR. Both groups received the same polyethylene cup.

Patients and methods 51 patients (52 hips) were included. Radiostereometry (RSA) and dual-energy X-ray absorptiometry (DEXA) were performed postoperatively and after 6, 12, and 24 months. 42 patients (43 hips) were followed for 2 years.

Results Mean cup rotation around the x-axis was 0.13° for the cemented group and –0.24° for the RH group (p = 0.03). Cup migration in the other axes, and stem migration and wear were similar between the 2 study groups. Bone remodeling around the cup was also similar between the groups. Bone loss in Gruen zone 1 was 18% for the cementless stems, as compared to an increase of 1.4% for the cemented ones (p < 0.001). Bone loss was similar in the other Gruen zones. Harris hip score and Oxford hip score were similar pre- and postoperatively in the 2 groups.

Interpretation In the present study, RH THR with a cementless hydroxyapatite-coated stem and conventional cemented THR did not show any major differences regarding stem migration and bone loss after 2 years of follow-up.     

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years

Background and purpose In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland.

Patients and methods 3,668 implants fulfilled our inclusion criteria. The previous data included years 1980–2001, whereas the current study includes years 1987–2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987–1996 and those operated 1997–2006.

Results The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987–1996 (62%; 95% CI: 57–67) and cementless group 2 (58%; CI: 52–66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62–80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987–1996 (0.49; CI: 0.32–0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001).

Interpretation Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.     

Less wear with aluminium-oxide heads than cobalt-chrome heads with ultra high molecular weight cemented polyethylene cups: A ten-year follow-up with radiostereometry

Purpose  

Wear is a major contributor to osteolysis and aseptic loosening of total hip replacements (THR). Both alumina (Al₂O₃) and cobalt-chrome (CoCr) femoral heads are commonly used. We investigated wear comparing alumina heads to cobalt-chrome heads against conventional cemented polyethylene (PE) cups for up to ten years.     

A comparison of cemented and cementless titanium femoral components used for primary total hip arthroplasty: a radiographic and survivorship study

Titanium has a low modulus of elasticity that makes it an attractive metal for femoral hip components. We directly compared 2 similar titanium stems, one cemented (n = 102 hips) and the other cementless (n = 78 hips), controlling for the most important surgical variables. The average radiographic follow-up was 6.7 and 7.0 years. Osteolysis below the joint line, zones 2 through 6, was 12.7% (13 of 102) in the cemented group and 0% in the cementless group (P<.001). There were 17 acetabular revisions in each study group. The cementless group had no femoral revisions, whereas 9 acetabular revisions in the cemented group had a simultaneous femoral revision (P=.005). Survivorship, defined as revision of the femur, was 84% for the cemented group and 100% for the cementless group at 10 years. Cementless titanium stems are more resistant to osteolysis and mechanical failure compared with similar cemented titanium stems.     

Cementless total hip replacement: past, present, and future

Cementless total hip replacement (THR) is rapidly being accepted as the surgery for arthritic diseases of the hip joint. The bone-ingrowth rate in porous-type cementless implants was about 90% over 10 years after surgery, showing that biological fixation of cementless THR was well maintained on both the stem and cup sides. As for the stress shielding of the femur operated using a distal fixation-type stem, severe bone resorption was observed. The severe bone resorption group showed continuous progression for more than 10 years after surgery. Stem loosening directly caused by stress shielding has been considered less likely; however, close attention should be paid to bone resorption-associated disorders including femoral fracture. Cementless cups have several specific problems. It is difficult to decide whether a cup should be placed in the physiological position for the case of acetabular dysplasia by bone grafting or at a relatively higher position without bone grafting. The bone-ingrowth rate was lower in the group with en bloc bone grafting, and the reactive line was frequently noted in the bone-grafted region. Although no data indicated that en bloc bone grafting directly led to poor outcomes, such as loosening, cup placement at a higher site without bone grafting is now selected by most operators. The polyethylene liner in a cementless cup is thinned due to the metal cup thickness; however, it has been suggested that the apparent relation between the cup size and the wear rate was absent as long as a cementless cup is used. Comparative study indicated cementless THR was inferior with regard to the yearly polyethylene wear rate and incidence of osteolysis on both the stem and cup sides. Meta-analysis study on the survival rate between cement and cementless THR reported that cemented THR was slightly superior. It should be considered that specific problems for cementless THR, especially with regard to polyethylene wear, do occur. This instructional lecture was presented at the 81st annual meeting of the Japanese Orthopaedic Association, Sapporo, May 2008     

A comparison of the outcome of cemented all-polyethylene and cementless metal-backed acetabular sockets in primary total hip arthroplasty

We compared, after a 10-year-minimum follow-up, the outcome of 50 cemented all-polyethylene Charnley acetabular sockets with that of 51 cementless metal-backed sockets in 2 comparable cohorts of young patients. Although the revision rate for the cemented and cementless group was 28% and 35%, respectively, the revision rate for aseptic loosening was 28% for the cemented and 12% for the cementless group. The mean polyethylene wear was 0.112 and 0.114 mm/y, respectively, for the 2 groups. Linear osteolysis was observed in 18 of 50 cemented sockets. Expansile osteolysis presented in 10 of 51 cementless sockets and only in one of the cemented sockets. In conclusion, cementless components had more durable fixation than cemented components. However, they presented more aggressive expansile osteolysis caused by the coexistence of polyethylene and metal debris.     

人工全髋置换骨水泥和无骨水泥假体术后疗效及假臼可能生存率比较

目的评价人工全髋关节置换术骨水泥和无骨水泥假体术后假臼可能生存率。方法对105例(108髋)进行随访,其中骨水泥组62例(63髋),无骨水泥组43例(45髋),并对术后患者进行综合性评价和分析。结果两组患者术后假臼可能生存率无显著差异。结论无论骨水泥假体还是无骨水泥假体患者术后疗效相似,假体都没有达到理想固定的效果。     

Outcome of primary total hip arthroplasty in Charnley Class C patients with juvenile idiopathic arthritis: a case series

The outcome and complications of 37 primary total hip arthroplasties by one surgeon in 24 patients with Charnley Class C juvenile idiopathic arthritis with up to 19.6 years follow-up are reported. Twenty-six femoral components were cementless; all acetabular components were cementless with screws. Age at operation averaged 22.6 years. Two patients (3 hips) have died. Twelve hips in 9 patients have failed. Six cementless acetabular components with conventional polyethylene were revised because of osteolysis after 5.5 to 14.5 years. All 3 cementless C2 femoral stems with minimal porous coating failed. One of eight cemented AML Bantam stems loosened at 3.5 years; 2 of 23 cementless AML Bantam stems loosened at 9.5 and 19.6 years. Pain relief and functional improvement are dramatic after total hip arthroplasty in juvenile idiopathic arthritis; however, the long-term outcome is guarded.     

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.     

Early failures among 14,009 cemented and 1,326 uncemented prostheses for primary coxarthrosis: The Norwegian Arthroplasty Register, 1987-1992

In the Norwegian Arthroplasty Register, 15,335 primary total hip replacements (THR) in patients with primary arthrosis were followed for 0-5.4 years.

The Kaplan-Meier estimate of cumulative failure (revision) after 4.5 years was 2.7 percent for cemented THR, compared to 6.5 percent for uncemented. In patients under 65 years the cumulative revisions for cemented and uncemented THR were 3.3 and 7.9 percent. For the acetabular components, the cumulative failures were 0.6 percent for cemented and 1.7 percent for uncemented, and for femoral components 1.7 and 3.9 percent after 4.5 years.

Adjusting for age and sex using a Cox regression model, 2 times higher rates of failure were found comparing uncemented to cemented THR. The results for uncemented prostheses were more unfavorable in young patients. In men and women under 60, the revision rates were increased 6 and 3 times, respectively, for patients with uncemented THR compared to those with cemented THR.

Restriction of the end-point to revision for aseptic loosening gave results similar to the over-all results. No difference between cemented and uncemented THR was seen for revisions due to infection, whereas the most unfavorable results for uncemented THR were seen when revisions due to causes other than infection and aseptic loosening were considered.     

Properties of tissue from around cemented joint implants with erosive and/or linear osteolysis

Levels of bone remodeling agents were measured in conditioned media from cultures of periprosthetic pseudosynovial membranes and related to the radiographic features of the failed joint implants. Radiographs of both cemented hip (n = 28) and cemented knee (n = 11) implants were examined and the pattern of radiolucency was classified as erosive, linear, or mixed. Similar levels of interleukin-1-beta (IL-1β), interleukin-6, tumor necrosis factor alpha (TNF-α), transforming growth factor beta-1, and prostaglandin E₂ (PGE₂) were found in pseudosynovial membrane conditioned media from all 3 groups of hips and the knee group (all linear). Significant correlations were evident only between PGE₂ and TNF-α levels in the linear hip group and PGE₂ and IL-1β levels in the knee group. A close correlation was found between IL-1β and TNF-α in both linear and erosive hips. It is suggested that coregulation of these bone remodeling agents differs with the radiographic appearance of the failed joint implants. As all the implants were cemented and the results contrast with those of others obtained with pseudosynovial membrane conditioned media from cementless implants, it is considered that cement critically influences the process of implant failure.     

The effects of prostaglandin E2 on DNA and collagen synthesis in osteoblastsIn Vitro

Summary The effects of prostaglandin E₂(PGE₂) on DNA and collagen synthesis in two separate cell populations were investigated. In view of their morphology, ALPase activity, DNA and collagen synthesis, and response to PGE₂, one population was in an undifferentiated state consisting of preosteoblast-like (PL) cells and the other was in a differentiated state consisting predominantly of osteoblastlike (OB) cells. As parameters of bone-forming activity, the incorporation of³H-thymidine into DNA and the incorporation of³H-proline into collagenase digestible protein were measured to assess DNA and collagen synthesis. The cells were treated with PGE₂ in the presence of indomethacin (IM) to avoid the influence of endogenous prostaglandins. At 24 hours, IM stimulated the DNA synthesis in both cell populations. Furthermore, a greater stimulation was found in the PL cells than in the OB cells. On the other hand, exogenously supplemented PGE₂ reversed the IM-induced stimulation of DNA synthesis. In contrast, high concentrations of PGE₂ alone increased the DNA synthesis. With respect to collagen synthesis, IM showed an inhibitory effect, especially in the PL cells. This inhibitory effect was also reversed by the addition of PGE₂. In addition to the stimulation of collagen synthesis, PGE₂ enhanced the proportion of protein synthesized as collagen. In the PL cells, the percentage of collagen synthesis was markedly decreased when cultured with IM for 48 hours. These results suggested that the effects of IM were mediated in part via its ability to reduce biosynthesis of prostaglandins, and that PGE₂ is a multifunctional autocrine regulator of bone formation.     

Total hip replacement:A meta-analysis to evaluate survival of cemented,cementless and hybrid implants

AIM To determine whether cemented, cementless, or hybrid implant was superior to the other in terms of survival rate.METHODS Systematic searches across MEDLINE, CINAHL, and Cochrane that compared cemented, cementless and hybrid total hip replacement(THR) were performed. Two independent reviewers evaluated the risk ratios of revision due to any cause, aseptic loosening, infection, and dislocation rate of each implants with a pre-determined form. The risk ratios were pooled separately for clinical trials, cohorts and registers before pooled altogether using fixed-effect model. Meta-regressions were performed to identify the source of heterogeneity. Funnel plots were analyzed. RESULTS Twenty-seven studies comprising 5 clinical trials, 9 cohorts, and 13 registers fulfilled the research criteria and analyzed. Compared to cementless THR, cemented THR have pooled RR of 0.47(95%CI: 0.45-0.48), 0.9(0.84-0.95), 1.29(1.06-1.57) and 0.69(0.6-0.79) for revision due to any reason, revision due to aseptic loosening, revision due to infection, and dislocation respectively. Compared to hybrid THR, the pooled RRs of cemented THR were 0.82(0.76-0.89), 2.65(1.14-6.17), 0.98(0.7-1.38), and 0.67(0.57-0.79) respectively. Compared to hybrid THR, cementless THR had RRs of 0.7(0.65-0.75), 0.85(0.49-1.5), 1.47(0.93-2.34) and 1.13(0.98-1.3).CONCLUSION Despite the limitations in this study, there was some tendency that cemented fixation was still superior than other types of fixation in terms of implant survival.     

Results of 3,668 primary total hip replacements for primary osteoarthritis in patients under the age of 55 years

Background and purpose

In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland.

Patients and methods

3,668 implants fulfilled our inclusion criteria. The previous data included years 1980–2001, whereas the current study includes years 1987–2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987–1996 and those operated 1997–2006.

Results

The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987–1996 (62%; 95% CI: 57–67) and cementless group 2 (58%; CI: 52–66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62–80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987–1996 (0.49; CI: 0.32–0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001).

Interpretation

Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland.Only a few register-based studies have yielded results of THA for primary osteoarthritis in younger patients at a population-based level (Havelin et al. 2000, Malchau et al. 2002, Eskelinen et al. 2005, 2006). In patients under the age of 55 years, data from population-based studies have suggested that the survival of cementless, proximally porous-coated stems can be as good as that of cemented stems (Havelin et al. 2000, Eskelinen et al. 2005). However, it has not been clear whether cementless cups perform as well as cemented cups in younger patients.On the basis of the Finnish Arthroplasty Register, we evaluated population-based data on the survival of primary total hip replacements performed for primary osteoarthritis in patients under the age of 55 years. The data including years 1980–2001 has been published earlier (Eskelinen et al. 2005), whereas the current study includes data from 1987 to 2006.     

Similar polyethylene wear between cemented and cementless Oxford medial UKA: a 5-year follow-up randomized controlled trial on 79 patients using radiostereometry

Background and purpose — Hydroxyapatite (HA)-coated implants have been associated with high polyethylene wear in hip arthroplasties. HA coating as a promoter of wear in knee arthroplasties has not been investigated. We compared the wear-rate of the polyethylene bearing for cemented and cementless HA-coated Oxford medial unicondylar knee arthroplasties (UKA). Secondarily, we investigated whether wear-rates were influenced by overhang or impingement of the bearing.

Patients and methods — 80 patients (mean age 64 years), treatment-blinded, were randomized to 1 of 3 Oxford medial UKA versions: cemented with double-pegged or single-pegged femoral component or cementless HA-coated with double-pegged femoral component (ratios 1:1:1). We compared wear between the cemented (n = 55) and cementless group (n = 25) (ratio 2:1). Wear, impingement, and overhang were quantified between surgery and 5-year follow-up using radiostereometry. Clinical outcome was evaluated with the Oxford Knee Score.

Results — The mean wear-rate for patients without bearing overhang was 0.04?mm/year (95% CI 0.02–0.07) for the cemented group and 0.05?mm/year (CI 0.02–0.08) for the cementless group. The mean difference in wear was 0.008?mm/year (CI –0.04 to 0.03). No impingement was identified. Half of the patients had medial bearing overhang, mean 2.5?mm (1–5). Wear increased by 0.014?mm/year for each mm increment in overhang. The mean Oxford Knee Score was 39 for the cementless group and 38 for the cemented group at the 5-year follow-up.

Interpretation — The wear-rates were similar for the 2 fixation methods, which supports further use of the cementless Oxford medial UKA. However, a caveat is a relatively large 95% CI of the mean difference in wear-rate. Component size and position is important as half of the patients presented with an additional increase in wear-rate due to medial bearing overhang.

Trial registration: ClinicalTrials.gov identifier: NCT00679120.     

Minimum 30-Year Results of Bilaterally Implanted Cemented and Cementless Total Hip Arthroplasty in Patients Younger Than 50 Years

BackgroundThe rate of failure of cemented and cementless total hip arthroplasty (THA) in younger patients is higher than that in elderly patients. The purpose of this study is to document the long-term clinical results of THA with the so-called third-generation cementing and the results of second-generation cementless THA in patients <50 years of age.MethodsThis study included 106 patients who had had bilateral THA with a cemented stem in one hip and a cementless stem in the other. There were 78 men and 28 women. Their mean age was 47 years (range, 21-49). The average follow-up duration was 31 years (range, 30-32.5).ResultsThere were similar mean Harris Hip Scores (90 versus 91 points) between the groups at the final follow-up. Forty-six acetabular components (43%) in the cemented group and 48 acetabular components (45%) in the cementless group were revised. Five femoral components (5%) in the cemented group and 4 femoral components (4%) in the cementless group were revised. Survivorship of the acetabular component at 30.8 years was similar in both groups (57% in the cemented group versus 55% in the cementless group). Survivorship of the femoral component at 30.8 years was also similar in both groups (95% in the cemented group versus 96% in the cementless group).ConclusionLong-term fixation of the cemented or cementless femoral stem was outstanding. There was a high rate of the acetabular component revision due to conventional polyethylene wear and periacetabular osteolysis in both hybrid and fully cementless THA groups.     

The Danish Hip Arthroplasty Register

In Denmark (5.3 mill. inhabitants), a national register for total hip replacements was established in January 1995. During the first 4 years, 18,222 primary total hip replacements (THR), 3,343 revisions and 6,071 follow-up examinations have been registered. During the same period, the incidence of primary THR per 100,000 inhabitants has increased from 72 in 1995 to 93 in 1998. The mean age at the primary replacement was 68 years, 59% were women and in 75% primary arthrosis was the diagnosis. An increasing use of uncemented implants has been observed both in primary THR and in revision. 64% of the primary THR were cemented and in revisions of both components, 49% were cemented. The reasons for revision were aseptic loosening in 63% of the cases followed by dislocation in 12% and deep infection in 11%. When assessed by the Harris Hip Score, primary THR and revisions resulted in a considerable improvement in pain and function, with the best results after primary operation. After 3 years, the prosthesis survival of all primary THR was approximately 97%. The lowest survival was observed in younger men with a hybrid prosthesis, usually uncemented cup and cemented stem.     

The Danish Hip Arthroplasty Register

ABSTRACT - In Denmark (5.3 mill. inhabitants), a national register for total hip replacements was established in January 1995. During the first 4 years, 18,222 primary total hip replacements (THR), 3,343 revisions and 6,071 follow-up examinations have been registered. During the same period, the incidence of primary THR per 100,000 inhabitants has increased from 72 in 1995 to 93 in 1998. The mean age at the primary replacement was 68 years, 59% were women and in 75% primary arthrosis was the diagnosis. An increasing use of uncemented implants has been observed both in primary THR and in revision. 64% of the primary THR were cemented and in revisions of both components, 49% were cemented. The reasons for revision were aseptic loosening in 63% of the cases followed by dislocation in 12% and deep infection in 11%. When assessed by the Harris Hip Score, primary THR and revisions resulted in a considerable improvement in pain and function, with the best results after primary operation. After 3 years, the prosthesis survival of all primary THR was approximately 97%. The lowest survival was observed in younger men with a hybrid prosthesis, usually uncemented cup and cemented stem.     

Cemented Polished Tapered Stems Have Lower Revision Rates Than Commonly Used Cementless Implant up to 17 Years of Follow-Up: An Analysis of 201,889 Total Hip Replacements From the Australian Orthopedic Association National Joint Replacement Registry

BackgroundData assessing femoral stems may be influenced by grouping together matt and polished stems, despite their differing reported survivorship. The aim of this study is to assess the difference in revision rates between commonly used cemented and cementless stems when polished tapered stems are assessed independently of matt stems.MethodsAustralian Orthopaedic Association National Joint Replacement Registry data from 1999 to 2019 were used to assess difference in revision rates between the 5 most commonly implanted femoral cemented and cementless stems for osteoarthritis. Cemented matt femoral stems, stems using line-to-line cementing techniques and procedures using non-cross-linked polyethylene, large head (>32 mm) metal-on-metal bearing surfaces or exchangeable necks were excluded. Cumulative percent revision was used to help compare survivorship between stems.ResultsThere were 201,889 total hip replacements meeting the inclusion criteria, of which 50.0% were cemented and 50.0% cementless. Cemented stems had a lower rate of revision at all time points compared to cementless stems. This was most significant during the first 2 weeks (hazard ratio 0.48, 95% confidence interval 0.40-0.58, P < .001) compared to 2 weeks postoperatively and onwards (hazard ratio 0.85, 95% confidence interval 0.81-0.90, P < .001). A subanalysis of head size, bearing type, and surgeon volume further supported the use of a cemented stem.ConclusionCommonly used cemented polished tapered stems have a lower revision rate when compared to commonly used cementless prostheses, and are recommended in all age groups for both low-volume and high-volume surgeons especially when head size 32 mm or smaller is used.     

Polyethylene Wear and Osteolysis Is Associated With High Revision Rate of a Small Sized Porous Coated THA in Patients With Hip Dysplasia

The outcome of 25 primary THAs in patients with hip dysplasia using the AML Bantam femoral stem (DePuy) is reported. Age at operation averaged 43 ± 10 years. Twenty-two of 25 stems were cementless. All cementless acetabular components had conventional or cross-linked polyethylene and screws. Follow-up averaged 11 ± 5 years (range 4–18). Four cementless stems were revised after 3, 4, 8, and 9 years; 2/3 cemented stems were revised at 8 and 18 years. Femoral revisions demonstrated extensive conventional polyethylene wear, periprosthetic osteolysis and loosening. Five entire cups were revised for wear and loosening; four liners were replaced. Harris Hip Scores for patients with retained stems went from 43 ± 12 to 85 ± 13. High revision rates with the proximally porous coated Bantam stem are due to loss of fixation, often associated with polyethylene wear and osteolysis.