Cemented or uncemented femoral component in primary total hip replacement? A review from a clinical and radiological perspective

Pre-clinical evaluation of the mechanical properties of a low-stiffness cement-injectable hip stem

In total hip arthroplasty (THA), the femoral stem can be fixed with or without bone cement. Cementless stem fixation is recommended for young and active patients as it eliminates the risk of loss of fixation at the bone-cement and cement-implant interfaces. Cementless fixation, however, suffers from a relatively high early revision rate. In the current research, a novel low-stiffness hip stem was designed, fabricated and tested. The stem design provided the option to inject biodegradable bone cement that could enhance initial stem stability. The stem was made of Ti6Al4V alloy. The proximal portion of the stem was porous, with cubic cells. The stem was fabricated using electron beam melting (EBM) technology and tested in compression and bending. Finite-element analysis was used to evaluate stem performance under a dynamic load representing a stair descending cycle and compare it to the performance of a solid stem with similar geometry. The von Mises stresses and maximum principal strains generated within the bone increased after porous stem insertion compared to solid stem insertion. The low-modulus stem tested in this study has acceptable mechanical properties and generates strain patterns in bone that appear compatible with clinical use.

Still no single gold standard for using cementless femoral stems routinely in total hip arthroplasty

Background

There is now a clear trend with increased usage of cementless femoral stems for all ages and most patients. As the number of total hip arthroplasties (THAs) performed annually continues to increase with expanding indications for THA and demands for improved quality of life, so will the prevalence of THA in the elderly and aging populations. This is worrisome as the risk of complications with cementless femoral stems increases in elderly patients and those with poor bone quality. The purpose of this study is to analyze the available data from comparative studies to determine whether cementless femoral stems are overused and whether cemented stems warrant increased consideration.

Methods

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, searches were performed to find original studies comparing cementless and cemented femoral stems; large population registry studies and reports were also included.

Results

This systematic review documents that older patients with cementless fixation increase the risk of revision, there is no clear fixation advantage in midaged patients, and younger patients fare better with cementless fixation. Complications after THA create burdens on the health care system and on patients.

Conclusions

Using evidence-based data should be better guidance in selecting the most reliable implants for THA. Although cementless femoral fixation for THA has evolved to the “new standard,” it has not been proven to be the “gold standard” for all patients.

Subsidence of the Corail femoral component in the elderly. A retrospective radiological review

206 patients age 70 years or older who underwent uncemented total hip arthroplasty (THA) using the Corail stem were studied. Radiographs taken post operatively and at one year were measured for subsidence of the stem. 13 patients had subsidence of the femoral stem of more than 2 mm. 5 of these were associated with fractures (mean age 78.06 years--average subsidence 14.52 mm), while 8 did not have associated fractures (mean age 77.43 years--average subsidence 4.99 mm). These 13 patients were then followed up for an average of 25 months (with fractures) and 26.88 months (without fractures). Radiographs were taken and measured for further subsidence using a VIDAR scanner. There was no evidence of further subsidence in any of the 13 patients, and all the stems had stabilised at one year with good evidence of osteointegration. None of the patients required revision. Uncemented THA using the Corail stem can be employed in this age group and poor bone quality is not a contraindication.

Predicting Bone Remodeling in Response to Total Hip Arthroplasty: Computational Study Using Mechanobiochemical Model

Periprosthetic bone loss following total hip arthroplasty (THA) is a serious concern leading to the premature failure of prosthetic implant. Therefore, investigating bone remodeling in response to hip arthroplasty is of paramount for the purpose of designing long lasting prostheses. In this study, a thermodynamic-based theory, which considers the coupling between the mechanical loading and biochemical affinity as stimulus for bone formation and resorption, was used to simulate the femoral density change in response to THA. The results of the numerical simulations using 3D finite element analysis revealed that in Gruen zone 7, after remarkable postoperative bone loss, the bone density started recovering and got stabilized after 9% increase. The most significant periprosthetic bone loss was found in Gruen zone 7 (−17.93%) followed by zone 1 (−13.77%). Conversely, in zone 4, bone densification was observed (+4.63%). The results have also shown that the bone density loss in the posterior region of the proximal metaphysis was greater than that in the anterior side. This study provided a quantitative figure for monitoring the distribution variation of density throughout the femoral bone. The predicted bone density distribution before and after THA agree well with the bone morphology and previous results from the literature.

Outcome of custom-made IMP femoral components of total hip arthroplasty: a follow-up of 15 to 22 years

A total of 1659 primary THAs using a cemented custom-made intra-operative manufactured prosthesis (IMP)-stem were studied. The end point for survival was defined as revision of the stem for any reason. Revision arthroplasty was performed in 49 cases. The IMP-stems had a revision free 20-year survival rate of 95.5%. Revisions were performed mainly because of aseptic loosening. There were no drawbacks like increased infection risk due to the prolonged surgical time needed for the intra-operative production of the stem. These data provide evidence that the cemented IMP-stem is able to provide good long-term results.

Evidence-based review for patients undergoing elective hip and knee replacement

BACKGROUND

The objective of this study was to evaluate the evidence for different interventions in the preoperative, perioperative and post-operative care for people undergoing elective total hip (THR) and knee (TKR) replacement surgery.

METHOD

A multidisciplinary working group comprising consumers, managers and clinicians from the areas of orthopaedics, rheumatology, aged care and rehabilitation evaluated randomized controlled trials (RCTs) and systematic reviews/meta-analyses concerning aspects of preoperative, perioperative and post-operative clinical care periods for THR/TKR through systematic searching of Medline, Embase, CENTRAL and the Cochrane Database of Systematic Reviews from May 2007 to April 2011. Multiple reviewers determined study eligibility and one or more members extracted primary study findings. The body of evidence were assessed and specific recommendations made according to NHMRC guidelines.

RESULTS

Twenty-five aspects were identified for review. Recommendations for 16 of 25 areas of care were made: impact of waiting, multidisciplinary preparation, preoperative exercise, smoking cessation, interventions for comorbid conditions, predictors of outcome, clinical pathways, implementation of a blood management programme, antibiotic prophylaxis, regional anaesthesia and analgesia, use of a tourniquet in knee replacement, venous thromboembolism prophylaxis, early post-operative cryotherapy, early mobilization and continuous passive motion. In the post-operative period, study heterogeneity across all aspects of care precluded specific recommendations.

CONCLUSIONS

There was a deficiency in the quality of the evidence supporting key aspects of the continuum of care for primary THR/TKR surgery. Consequently, recommendations were limited. Prioritization and funding for research into areas likely to impact clinical practice and patient outcomes after elective joint replacement surgery are the next important steps.

Epidemiology of primary hip and knee arthroplasties in Germany: 2004 to 2008

The objective of this study was to describe the trend in utilization of primary joint arthroplasties in Germany. Between 2004 and 2008, the number of total knee arthroplasties (TKAs) increased faster than that of total hip arthroplasties (THAs). In 2008, 159000 primary THAs and 146000 primary TKAs were performed. This represented a 15% increase in THAs and a 33% increase in TKAs compared to 2004. The annual increase in number of surgeries was 4500 for THAs and 9,000 for TKAs. Although older adults remained the main recipients of joint arthroplasties, incidence rate increased faster in non-elderly(18-64 years) compared with elderly (≥65 years) in both THAs and TKAs. Obesity, more strongly associated with TKAs than with THAs, could be a contributor to the recent steeper growth in TKAs in Germany.

Cemented versus uncemented hemiarthroplasty for hip fractures: a systematic review of randomised controlled trials

We performed a systematic review of randomised controlled trials in order to identify the best available evidence to compare the outcome between cemented and uncemented hemiarthroplasty for treatment of intracapsular hip fractures. We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, EMBASE, CINAHL, MEDLINE and the National Research Register (UK) to retrieve all of the published randomised controlled trials designed to address these issues, in order to perform a meta-analysis. Eight studies involving 1169 patients were determined to be appropriate for meta-analysis. The following statistically significant differences were found between the cemented and uncemented prostheses: (1) longer operative time for cemented prosthesis; (2) lower reduction in mobility score for those treated with cemented prosthesis; (3) fewer patients with residual pain in the hip and lower pain score (signifying less pain) for those treated with a cemented prosthesis. Our meta-analysis has shown that there is good evidence that the use of cement during hemiarthroplasty will reduce the amount of residual hip pain and also allow better restoration of function. There is no evidence of significant adverse effects of cement on mortality or other complications encountered. These observations apply to older designs, and there is a need for randomised trials comparing hydroxyapatite-coated modern stems with cemented prostheses.

Total Hip Arthroplasty - over 100 years of operative history

Total hip arthroplasty (THA) has completely revolutionized the nature in which the arthritic hip is treated, and is considered to be one of the most successful orthopaedic interventions of its generation. With over 100 years of operative history, this review examines the progression of the operation from its origins, together with highlighting the materials and techniques that have contributed to its development. Knowledge of its history contributes to a greater understanding of THA, such as the reasons behind selection of prosthetic materials in certain patient groups, while demonstrating the importance of critically analyzing research to continually determine best operative practice. Finally, we describe current areas of research being undertaken to further advance techniques and improve outcomes.

Effect of surgical approach for total hip replacement on hip function using Harris Hip scores and Trendelenburg's test. A retrospective analysis

OBJECTIVE

A retrospective analysis of osteoarthritis patients undergoing primary hip arthroplasty, to assess which surgical approach produces the best functional results at one-year post-operatively, using common clinical scoring systems and tests. The aim of this study was to compare the anterolateral and the posterior approaches to total hip arthroplasty using Harris Hip scores and Trendelenburg's test by looking at pre-operative results and comparing them to post-operative results.

METHODS

Data from 3416 consecutive cases were extracted from a multicentre database, maintained by the Tayside Arthroplasty Audit Group (TAAG) situated in Tayside, using only patients who had undergone a primary hip arthroplasty and had a clinical diagnosis of osteoarthritis.

RESULTS

Analysis showed that there was statistically significant difference between the two approaches for Harris Hip score (p = 0.0344), Harris Hip function score (p = 0.0035) and Trendelenburg Test (p =< 0.00001). The posterior approach showed larger improvements in Harris Hip scores. There was an increased incidence of dislocation in the posterior approach group (6.9%) but an increased incidence of Trendelenburg gait in anterolateral approach group (5.7%). It was found that patients who suffered a dislocation had similar functional outcomes for both groups with no statistical difference.

CONCLUSIONS

These results suggest that there may be benefit in using a posterior approach to primary total hip arthroplasty but due to limitations of the data within this study further more detailed research is required.

Recent developments in total hip replacements: cementation, articulation, minimal-invasion and navigation

Total hip replacement is a commonly performed procedure with good results. The implants could be cemented or cementless, and there has been a resurgence of resurfacing procedures. It is important that special consideration is given to the choice of the material used at the bearing surfaces. There have been many developments in recent years that influence our choice of implant and have shaped our practice, including minimally invasive surgery and computer-assisted surgery. This article aims to provide an overview of these developments.

Health Technology Assessment: managing the introduction and use of medical devices in clinical practice in Italy

Technology assumes a key role in current clinical practice. A number of innovative or improved products are constantly being launched on the market and offered directly to the users (i.e., clinicians) or even to the patients. However, in most cases, the regulation for admission to commerce is slower than the innovation process and may be inadequate for assessing the real clinical effectiveness and safety of medical devices in the premarket phase. Health Technology Assessment (HTA) can be used as a tool for the evaluation of clinical effectiveness, cost-effectiveness and risk to patients of medical devices. HTA products (e.g., periodic reports) may aid healthcare payers to make informed choices regarding the appropriate use, coverage and reimbursement of medical devices. We present the strengths and limitations of the first three Italian HTA reports we coauthored and critically explore some of the aspects related to the introduction, adoption and use of medical technologies in clinical practice.

Bisphosphonate-laden acrylic bone cement: mechanical properties, elution performance, and in vivo activity

Cemented total hip replacements generally fail after 10-20 years, often due to implant loosening from bone resorption. Bisphosphonates such as zoledronic acid (ZA) and pamidronate (PAM) are potent inhibitors of bone resorption. The local delivery of bisphosphonates via acrylic bone cement could decrease osteolysis and prolong implant lifespan. Conflicting studies suggest that bisphosphonate loading may or may not reduce the mechanical properties of acrylic bone cement. We assayed acrylic bone cement laden with ZA or PAM at different concentrations and diluent volumes. Four-point bend testing and compressive testing indicated that high volumes of diluent (with or without bisphosphonate) significantly reduced bending modulus and compressive strength. Radiography and electron microscopy indicated that high diluent volumes generated abnormal acrylic bone cement structure. After 6 weeks of incubation in saline, only 0.9% w/w of the total bisphosphonate incorporated in acrylic bone cement eluted in vitro, indicating a slow elution rate. In vivo testing was performed using a rat model. Cement cylinders were inserted into incisions in rat distal femora and ZA delivered locally (via elution from acrylic bone cement) or systemically (via injection). At 4 weeks postoperatively, dual energy X-ray absorptiometry demonstrated no significant increase in local bone mineral density (BMD) adjacent to ZA-laden implants. In contrast, systemic ZA delivery (0.1 mg/kg) led to a large (48.6%) and significant increase in BMD. Thus, systemic delivery appears more effective than local delivery.

Health service costs in Europe: cost and reimbursement of primary hip replacement in nine countries

This paper assesses variations in the cost of primary hip replacement between and within nine member states of the European Union (EU). It also compares the cost of service with public-payer reimbursements. To do so, data on cost and reimbursement were surveyed at the micro-level in 42 hospitals in Denmark, England, France, Germany, Hungary, Italy, The Netherlands, Poland, and Spain. The total cost of treatment ranged from 1290 euros (Hungary) to 8739 euros (The Netherlands), with a mean cost of 5043 euros (STD +/- 2071 euros). The main cost drivers were found to be implants (34% of total cost on average) and ward costs (20.9% of total cost on average). A one-way random effects analysis of variance model indicated that 74.0% of variation was between and only 26% of variation was within countries. In a two-level random-intercept regression model, purchasing-power parities explained 79.4% of the explainable between-country variation, while the percentage of uncemented implants used and the number of beds explained 12.1 and 1.6% of explainable within-country variation, respectively. The large differences in cost and reimbursement between Poland, Hungary, and the other EU member states shows that primary total hip replacement is a highly relevant case for cross-border care.

Hybrid total hip replacement: outcome after a mean follow up of 10 years

BACKGROUND

Total hip replacement is one of the most successful surgical procedures of the modern surgical era. The method of fixation of implants continues to evolve, and as cemented acetabular fixation appears to be less durable than anticipated, the use of a cemented stem and an uncemented acetabulum - a so-called 'hybrid hip'- has become more popular. This paper reports the results of hybrid total hip replacement at an average of 10 years postoperatively.

METHODS

Primary hybrid total hip replacements carried out by a single surgeon in 1994 and 1995 were identified; patients were sent Oxford Hip Score and EuroQuol-5 Dimension quality-of-life questionnaires and, where necessary, a radiograph appointment. Questions about diabetes, cigarette smoking and hip dislocation were included. First postoperative and final radiographs were compared for stem subsidence, cup migration, stem position, osteolysis of the femur and pelvis, and evidence of loosening of both components.

RESULTS

At 10-year follow up the revision rate for femoral component loosening was 2.9%. Fifteen per cent showed some abnormality at the femoral interface, not related to stem size and more common in titanium stems. Average hip score was 20.9, and quality-of-life measures indicated a high level of satisfaction.

CONCLUSIONS

Hybrid total hip replacement gives excellent clinical outcomes with low revision rates for both components. The one-piece uncemented cup offers important advantages over modular devices, the use of which should be re-evaluated.