Direct comparison of polyethylene wear in cemented and uncemented acetabular cups

To cement or not to cement acetabular cups in total hip arthroplasty: a systematic review and re-evaluation

INTRODUCTION

Total Hip Arthroplasty (THA) in the treatment of primary osteoarthritis of the hip has evolved to a very safe and cost-effective intervention with revision rates below 5% after 10 years. To this day, however, controversy remains on whether or not to cement the acetabular cup.

METHODS

A comprehensive PubMed search of the English literature for studies published between 2007 and 2018 was performed. Studies comparing the clinical (revision rate, functionality), radiological (wear) or economic (cost) differences between cemented (cemented stem with cemented cup) and hybrid (cemented stem with uncemented cup) prostheses for primary osteoarthritis of the hip were identified as eligible.

RESULTS

A total of 1032 studies were identified whereof twelve were included for qualitative synthesis. All studies concerning the risk of revision were based on registry data, covering a total of 365,693 cups. Cemented prostheses had a similar or lower risk of revision compared to hybrid prostheses in every study, but performed slightly worse on functionality and quality of life. While cemented prostheses were the cheapest option, hybrids were the most cost-effective.

DISCUSSION

The widespread preference for cementless fixation of the acetabulum cannot be explained by a superior survival of cementless or hybrid models. Irrespective of age, cemented fixation of the acetabulum remains the gold standard to which other techniques should be compared.

Postoperative Deep Infection After Cemented Versus Cementless Total Hip Arthroplasty: A Meta-Analysis

Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty (THA). The objective of this meta-analysis was to compare the PJI rate between cemented and cementless THAs. Eight clinical studies (2 randomized controlled trials and 6 observational studies) were available for the analysis. Meta-analysis (with a fixed-effects model) and subgroup analysis were performed by research design and meta-regression was performed by continuous moderator. The overall incidence of PJI was 0.4% (357/84,200). The incidence was 0.5% (310/67,531) in cemented group, and 0.3% (47/16,669) in cementless group (P=0.008). The meta-analysis revealed that the use of cement in THA was associated with an increased risk of PJI (odds ratio 1.53; 95% confidence interval 1.120 to 2.100; P=0.008).

The cost analysis of cemented versus cementless total hip replacement operations on the NHS

In a time of limited resources, the debate continues over which types of hip prosthesis are clinically superior and more cost-effective. Orthopaedic surgeons increasingly need robust economic evidence to understand the full value of the operation, and to aid decision making on the 'package' of procedures that are available and to justify their practice beyond traditional clinical preference. In this paper we explore the current economic debate about the merits of cemented and cementless total hip replacement, an issue that continues to divide the orthopaedic community.

Clinical outcome, survival and polyethylene wear of an uncemented total hip arthroplasty: a 10- to 12-year follow-up study of 81 hips

A complete 10- to 12-year follow-up of an uncemented total hip arthroplasty (THA) was performed regarding survival, clinical outcome, polyethylene wear and influencing factors on wear. Seventy-two patients (75 Mallory Head uncemented THA) with primary osteoarthritis operated on in 1999 or 2000 were included in the survival study. Mean age at the time of operation was 57.9 years (range 37-70). The survival rate after 11.9 years was 96% (95% CI 0.89-1.01). In three cases the acetabular component was revised because of extensive polyethylene wear. Fifty-four patients with 57 THAs were available for clinical and radiological analysis. At a mean follow-up time of 10.7 years (range 10-12) the clinical outcome can be considered comparable to other uncemented THA. Mean polyethylene wear was 1.8mm (range 0.4-3.8) with an annual wear rate of 0.15 mm/y. There was a significant correlation between polyethylene wear and inclination of the cup as well as male gender.

Accelerated polyethylene wear and early failure of the uncemented Reflection acetabular component: a ten to fifteen-year follow-up study

PURPOSE

The Reflection® second-generation uncemented acetabular component was designed to address increased rates of failure observed with the early acetabular designs. However, the reported survivorship of this acetabular component has been conflicting. The aim of this study was to describe the ten to 15-year survivorship and polyethylene wear rate for the uncemented Reflection® acetabular component performed as part of a primary total hip replacement.

METHODS

One hundred and four consecutive Reflection® uncemented acetabular components in 97 patients were identified from a prospective arthroplasty database with a minimum of ten years of follow-up. No patient was lost to follow-up. Mean cohort age was 59.1 years.

RESULTS

There were 24 revisions of the acetabular component. The all-cause survival rate at ten years was 77.2% [95% confidence interval (CI) 73.9-80.5]. Mean linear wear was 0.20 mm [standard deviation (SD) 0.08] per year and the volumetric wear was 106.2 mm(3) per year. At final follow-up, more than half the patients had osteolysis identified around the femoral component. The mean Oxford Hip Score was 35.6 (SD 9.8) at a mean follow-up of 11.9 years, with six (11.1%) excellent, 26 (48.1%) good, 17 (31.5%) fair and five (9.3%) poor outcomes. Despite the fact that more than a third had a fair or poor outcome, only four (7.4%) were not satisfied with their hip.

CONCLUSIONS

Due to the high rate of relatively asymptomatic polyethylene wear and osteolysis associated with this acetabular component, in our department, we now review all surviving patients both clinically and radiographically on an annual basis.

Cemented versus uncemented fixation in total hip replacement: a systematic review and meta-analysis of randomized controlled trials

The optimal method of fixation for primary total hip replacements (THR), particularly fixation with or without the use of cement is still controversial. In a systematic review and metaanalysis of all randomized controlled trials comparing cemented versus uncemented THRS available in the published literature, we found that there is no significant difference between cemented and uncemented THRs in terms of implant survival as measured by the revision rate. Better short-term clinical outcome, particularly an improved pain score can be obtained with cemented fixation. However, the results are unclear for the long-term clinical and functional outcome between the two groups. No difference was evident in the mortality and the post operative complication rate. On the other hand, the radiographic findings were variable and do not seem to correlate with clinical findings as differences in the surgical technique and prosthesis design might be associated with the incidence of osteolysis. We concluded in our review that cemented THR is similar if not superior to uncemented THR, and provides better short term clinical outcomes. Further research, improved methodology and longer follow up are necessary to better define specific subgroups of patients in whom the relative benefits of cemented and uncemented implant fixation can be clearly demonstrated.

Is there evidence for accelerated polyethylene wear in uncemented compared to cemented acetabular components? A systematic review of the literature

Joint arthroplasty registries show an increased rate of aseptic loosening in uncemented acetabular components as compared to cemented acetabular components. Since loosening is associated with particulate wear debris, we postulated that uncemented acetabular components demonstrate a higher polyethylene wear rate than cemented acetabular components in total hip arthroplasty. We performed a systematic review of the peer-reviewed literature, comparing the wear rate in uncemented and cemented acetabular components in total hip arthroplasty. Studies were identified using MEDLINE (PubMed), EMBASE and the Cochrane Central Register of Controlled Trials. Study quality was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The search resulted in 425 papers. After excluding duplicates and selection based on title and abstracts, nine studies were found eligible for further analysis: two randomised controlled trials, and seven observational studies. One randomised controlled trial found a higher polyethylene wear rate in uncemented acetabular components, while the other found no differences. Three out of seven observational studies showed a higher polyethylene wear in uncemented acetabular component fixation; the other four studies did not show any differences in wear rates. The available evidence suggests that a higher annual wear rate may be encountered in uncemented acetabular components as compared to cemented components.

Fixation method does not affect restoration of rotation center in hip replacements: a single-site retrospective study

BACKGROUND

Aseptic loosening is one of the greatest problems in hip replacement surgery. The rotation center of the hip is believed to influence the longevity of fixation. The aim of this study was to compare the influence of cemented and cementless cup fixation techniques on the position of the center of rotation because cemented cup fixation requires the removal of more bone for solid fixation than the cementless technique.

METHODS

We retrospectively compared pre- and post-operative positions of the hip rotation center in 25 and 68 patients who underwent artificial hip replacements in our department in 2007 using cemented or cementless cup fixation, respectively, with digital radiographic image analysis.

RESULTS

The mean horizontal and vertical distances between the rotation center and the acetabular teardrop were compared in radiographic images taken pre- and post-operatively. The mean horizontal difference was -2.63 mm (range: -11.00 mm to 10.46 mm, standard deviation 4.23 mm) for patients who underwent cementless fixation, and -2.84 mm (range: -10.87 to 5.30 mm, standard deviation 4.59 mm) for patients who underwent cemented fixation. The mean vertical difference was 0.60 mm (range: -20.15 mm to 10.00 mm, standard deviation 3.93 mm) and 0.41 mm (range: -9.26 mm to 6.54 mm, standard deviation 3.58 mm) for the cementless and cemented fixation groups, respectively. The two fixation techniques had no significant difference on the position of the hip rotation center in the 93 patients in this study.

CONCLUSIONS

The hip rotation center was similarly restored using either the cemented or cementless fixation techniques in this patient cohort, indicating that the fixation technique itself does not interfere with the position of the center of rotation. To completely answer this question further studies with more patients are needed.

Patient weight more than body mass index influences total hip arthroplasty long term survival

The effect of obesity on the long-term survival of total hip arthroplasty remains under discussion. Reviewing meta-analyses of large cohort studies a high body mass index has been correlated with a higher incidence of complications but not univocally with a lower implant survival rate. It has been suggested that body weight rather than body mass index might be a better parameter to evaluate prosthesis outcome. We reviewed 27,571 patients retrospectively with primary arthritis as a preoperative diagnosis. Patients were divided into 4 categories based on their body mass index, or into two groups based on the body weight (<80 kg and =80 kg). Implant survivorship was estimated with use of the Cox proportional hazards model with revision for aseptic loosening as the end point. Results were stratified for sex and implant tribology. When body mass index was used the 10 years implant survival in obese versus non-obese patients was not statistically different (p=0.058), but when body weight was used a statistically different implant survivorship was found for men (p=0.009). Therefore, weight rather than than body mass index influences survival of hip prostheses, and should be used as the discriminant parameter for further studies.

Total hip arthroplasty: to cement or not to cement the acetabular socket? A critical review of the literature

The optimal method for acetabular socket fixation remains controversial. We present a critical analysis of the current evidence from a systemic literature review of comparative studies, long-term case series, prior literature reviews, meta-analysis, and national arthroplasty registry data for cemented and uncemented acetabular components to determine the respective survivorship rates, overall risk of re-operation, dislocation rates, and wear-related complications. Using contemporary techniques, both cemented and uncemented sockets can yield good long-term results, but our evaluation suggests that the overall/all cause re-operation risk is lower for cemented fixation. Until and unless crosslinked polyethylene (PE) liners or alternative bearings can prove to yield superior outcome in the future, the cemented PE cup remains the gold standard, in all age groups, by which every acetabular component should be compared.

The influence of acetabular inclination angle on the penetration of polyethylene and migration of the acetabular component

In this prospective study we studied the effect of the inclination angle of the acetabular component on polyethylene wear and component migration in cemented acetabular sockets using radiostereometric analysis.

A total of 120 patients received either a cemented Reflection All-Poly ultra-high-molecular-weight polyethylene or a cemented Reflection All-Poly highly cross-linked polyethylene acetabular component, combined with either cobalt–chrome or Oxinium femoral heads. Femoral head penetration and migration of the acetabular component were assessed with repeated radiostereometric analysis for two years. The inclination angle was measured on a standard post-operative anteroposterior pelvic radiograph. Linear regression analysis was used to determine the relationship between the inclination angle and femoral head penetration and migration of the acetabular component.

We found no relationship between the inclination angle and penetration of the femoral head at two years’ follow-up (p = 0.9). Similarly, our data failed to reveal any statistically significant correlation between inclination angle and migration of these cemented acetabular components (p = 0.07 to p = 0.9).

Polyethylene wear is related to patient-specific contact stress in THA

BACKGROUND

General numerical models of polyethylene wear and THA simulators suggest contact stresses influence wear. These models do not account for some patient-specific factors. Whether the relationship between patient-specific contact stress and wear apply in vivo is unclear.

QUESTIONS/PURPOSES

We therefore determined whether (1) contact stress distribution at the prosthesis-cup interface and (2) hip geometry and cup inclination are related to wear in vivo.

METHODS

We retrospectively reviewed the radiographs of 80 patients who had aseptic loosening of their THAs as determined by radiographic criteria. We determined linear penetration and volumetric wear using postoperative and last followup radiographs. Contact stress distribution was determined by the HIPSTRESS method. The biomechanical model was scaled to fit the patient's musculoskeletal geometry of the pelvis, trochanteric position, and cup inclination using the standard postoperative radiograph.

RESULTS

Linear penetration and volumetric wear correlated with peak contact stress. Polyethylene wear was greater in THAs with a medial position of the greater trochanter and smaller inclination of the acetabular cup.

CONCLUSIONS

Our observations suggest wear is specific to contact stresses in vivo.

CLINICAL RELEVANCE

Long-term wear in a THA can be estimated using contact stress analysis based on analysis of the postoperative AP radiograph.

Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up

BACKGROUND

Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up.

MATERIALS AND METHODS

Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10-14 years).

RESULTS

Average Harris Hip Score was 56 ± 9 (range 45-69) preoperatively, 90 ± 9 (range 81-100) 12 months after surgery, and 91 ± 8 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised.

CONCLUSIONS

Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results.