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

Total hip arthroplasty with modular stem for Crowe I and II developmental dysplasia of the hip

BACKGROUND

The variation of femoral anteversion is not completely consistent with the grade of developmental dysplasia of the hip (DDH), which poses challenges to hip replacement with the non-modular tapered stem. Currently, whether the modular stem should be used in Crowe I and II DDH is still controversial. The aim of this study is to compare the clinical efficacy of the modular stem and the non-modular tapered stem in Crowe I and II DDH patients.

METHODS

We retrospective analyzed the clinical data of 196 patients with unilateral Crowe I and II DDH from January 2015 to January 2017. One hundred patients were operated by an experienced surgeon with the modular stems; the remaining 96 patient was operated by another equivalent surgeon with the non-modular tapered stems. The preoperative basic information, operating time, intraoperative and postoperative complications, postoperative leg length discrepancy (LLD) and offset, Harris hip score (HHS), and forgotten joint score (FJS) in postoperative 2 years were collected and analyzed.

RESULTS

Postoperative LLD (P = 0.010) and FJS (P = 0.001) had significant difference between two groups. Concurrent acceptable LLD and offset were achieved in 87% of patients with the modular stem and in 68% of patients with the non-modular stem (P = 0.001). There was no significant difference in the operating time (P = 0.086), intraoperative complication (P = 0.096), postoperative dislocation rate (P = 0.056), postoperative offset difference (P = 0.108), and Harris score (P = 0.877) between two groups.

CONCLUSIONS

Compared with the non-modular tapered stem, the modular stem was more likely to provide accurate reconstruction and forgotten artificial hip for Crowe I and II DDH patients. We recommend the modular stem as routine choice for these patients.

Fifteen-Year Results of Total Hip Arthroplasty With Cobalt-Chromium Femoral Heads on Highly Cross-Linked Polyethylene in Patients 50 Years and Less

BACKGROUND

Highly cross-linked polyethylene (HXLPE) is the most commonly used bearing surface in total hip arthroplasty (THA) because of its superior wear properties, but long-term results in young patients are limited. Mid-term survivorship has been promising; however, polyethylene wear rates and need for revision surgeries remain a concern in this population. The purpose of our study is to investigate polyethylene wear rates, implant survivorship, wear-related revisions, and patient-reported outcomes in a young patient cohort at 15-year follow-up.

METHODS

We performed a retrospective study of a prospective longitudinal cohort of 82 consecutive patients (89 hips) who underwent primary THA with an HXLPE acetabular liner and a cobalt-chromium femoral head. The mean age at the time of surgery for the cohort was 38.8 years (range 12-50). All patients received HXLPE liners with a cementless acetabular component coupled with a cobalt-chrome femoral head through a posterior approach with a cementless femoral component. All components were from a single manufacturer. We recorded University of California, Los Angeles Activity, and modified Harris Hip Scores. Wear calculations were made using the Martell Hip Analysis Suite (Version 8.0.4.3).

RESULTS

At average 15 years (range 13.1-18.5), there was a revision-free survivorship of 97.8% in our HXLPE group with no wear-related revisions. We observed a linear wear rate of 0.0185 mm/y (standard deviation 0.05) after accounting for a 1-year bedding-in period. The volumetric wear rate was found to be 12.80 mm³/y (standard deviation 22.69). These numbers are registered as clinically undetectable and are comparable to steady state wear rates in the same cohort of patients at earlier time points. We found no radiographic changes concerning osteolysis. We observed excellent patient-reported outcomes at this time point with improvements in modified Harris Hip Scores (35.3 [22.5], P < .0001) and University of California, Los Angeles Activity Scores (median 6.0, P < .0001).

CONCLUSION

At 15-year follow-up, we demonstrated that HXLPE bearings in this young cohort had excellent wear properties, maintained superior clinical improvements, and underwent no wear-related revision operations. The HXLPE and cobalt-chrome bearing couple continues to be extremely effective 15 years after primary THA in patients less than 50 years.

LEVEL OF EVIDENCE

IV.

Age and Early Revision After Primary Total Hip Arthroplasty for Osteoarthritis

Prior reports have noted an increased risk of early revision among younger patients undergoing total hip arthroplasty (THA) but have been confounded by the inclusion of various diagnoses. The purpose of this study was to assess the revision rate and the time to revision for patients undergoing THA for osteoarthritis based on age. Patients with a diagnosis of osteoarthritis who underwent both primary and revision THA at the same institution were identified. The time between primary and revision surgery and the indication for revision were collected. Patients were stratified into 2 groups based on age at the time of primary THA: 64 years or younger (group 1) or 65 years or older (group 2). Between 1996 and 2016, a total of 4662 patients (5543 hips) underwent primary THA for a diagnosis of osteoarthritis. Of these, 100 patients (104 hips) received a revision THA (62 in group 1 and 42 in group 2). Mean age was 52.7±8.4 years in group 1 vs 73.4±6.3 years in group 2 (P<.001). There was no significant difference in mean body mass index (29.7±7.3 kg/m² vs 28.4±4.6 kg/m², P=.30). Rate of revision was not significantly different between the groups (1.8% vs 2.0%, P=.7). Average time from primary to revision surgery was 3.0±3.2 years for group 1 and 1.1±2.1 years for group 2 (P=.001). Among patients undergoing primary THA for a diagnosis of osteoarthritis, younger age is not associated with an increased rate of early failure or revision. [Orthopedics. 2017; 40(6):e1069-e1073.].

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.

A bias-adjusted evidence synthesis of RCT and observational data: the case of total hip replacement

Evaluation of clinical effectiveness of medical devices differs in some aspects from the evaluation of pharmaceuticals. One of the main challenges identified is lack of robust evidence and a will to make use of experimental and observational studies (OSs) in quantitative evidence synthesis accounting for internal and external biases. Using a case study of total hip replacement to compare the risk of revision of cemented and uncemented implant fixation modalities, we pooled treatment effect estimates from OS and RCTs, and simplified existing methods for bias-adjusted evidence synthesis to enhance practical application. We performed an elicitation exercise using methodological and clinical experts to determine the strength of beliefs about the magnitude of internal and external bias affecting estimates of treatment effect. We incorporated the bias-adjusted treatment effects into a generalized evidence synthesis, calculating both frequentist and Bayesian statistical models. We estimated relative risks as summary effect estimates with 95% confidence/credibility intervals to capture uncertainty. When we compared alternative approaches to synthesizing evidence, we found that the pooled effect size strongly depended on the inclusion of observational data as well as on the use bias-adjusted estimates. We demonstrated the feasibility of using observational studies in meta-analyses to complement RCTs and incorporate evidence from a wider spectrum of clinically relevant studies and healthcare settings. To ensure internal validity, OS data require sufficient correction for confounding and selection bias, either through study design and primary analysis, or by applying post-hoc bias adjustments to the results. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

Functional outcomes of total hip arthroplasty in patients aged 30 years or less: a systematic review and meta-analysis

INTRODUCTION

Young adult hip surgery is a growing subspecialty. Increasingly total hip arthroplasty (THA) is offered to patients aged 30 or less suffering from end-stage hip arthropathy from a variety of congenital, developmental and acquired conditions. There is a paucity of evidence to advise such patients and surgeons alike on the functional outcomes of THA in this age group, as individual studies tend to include small cohorts.

METHODS

A systematic review and meta-analysis was performed to assess whether THA in patients aged 30 years or less provides significant functional improvement. The primary outcome measure was change in Harris Hip Score. Secondary outcome measures were implant survivorship and the effect of fixation type and bearing surface.

RESULTS

The results of 743 primary THA procedures were included. Weighted mean patient age was 22.7 years. Harris Hip Score improved by a weighted mean difference of 42.17 points out of 100 (95% confidence interval, 36.48-47.86 points, p&lt;0.001) after THA at a weighted mean follow-up of 8.4 years. Pooled revision rate was 5.0% for the same time period.

CONCLUSIONS

This is the largest review to date of THA in patients aged 30 or less. The results show significant functional improvement measured by Harris Hip Score. The revision rate of 5% at 8.4 years is comparable to the general THA population. This contrasts high revision rates reported in older reviews of the literature, suggesting adoption of improved techniques and implants in the more recent literature.

Contemporary Surgical Indications and Referral Trends in Revision Total Hip Arthroplasty: A 10-Year Review

BACKGROUND

Revision total hip arthroplasty (THA) represents nearly 15% of all hip arthroplasty procedures in the United States and is projected to increase. The purpose of our study was to summarize the contemporary indications for revision THA surgery at a tertiary referral medical center. We also sought to identify the indications for early and late revision surgery and define the prevalence of outside institution referral for revision THA.

METHODS

Using our institution's arthroplasty registry, we identified a retrospective cohort of 870 consecutive patients who underwent revision THA at our hospital from 2004 to 2014. Records were reviewed to collect data on patient's primary and revision THA procedures, and the interval between primary THA and revision surgery was determined.

RESULTS

Aseptic loosening (31.3%), osteolysis (21.8%), and instability (21.4%) were the overall most common indications for revision THA and the most common indications for revision surgery within 5 years of primary THA. Aseptic loosening and osteolysis were the most common indications for revision greater than 5 years from primary THA. Only 16.4% of revised hips had their index arthroplasty performed at our hospital, whereas 83.6% were referred to our institution.

CONCLUSIONS

Aseptic loosening, osteolysis, and instability remain the most common contemporary indications for revision THA in an era of alternative bearings and modular components. Most of our revisions were referred from outside institutions, which highlights the transfer of a large portion of the revision THA burden to tertiary referral centers, a pattern that could be exacerbated under future bundled payment models.

Hip resurfacing versus total hip arthroplasty: a systematic review comparing standardized outcomes

BACKGROUND

Metal-on-metal hip resurfacing was developed for younger, active patients as an alternative to THA, but it remains controversial. Study heterogeneity, inconsistent outcome definitions, and unstandardized outcome measures challenge our ability to compare arthroplasty outcomes studies.

QUESTIONS/PURPOSES

We asked how early revisions or reoperations (within 5 years of surgery) and overall revisions, adverse events, and postoperative component malalignment compare among studies of metal-on-metal hip resurfacing with THA among patients with hip osteoarthritis. Secondarily, we compared the revision frequency identified in the systematic review with revisions reported in four major joint replacement registries.

METHODS

We conducted a systematic review of English language studies published after 1996. Adverse events of interest included rates of early failure, time to revision, revision, reoperation, dislocation, infection/sepsis, femoral neck fracture, mortality, and postoperative component alignment. Revision rates were compared with those from four national joint replacement registries. Results were reported as adverse event rates per 1000 person-years stratified by device market status (in use and discontinued). Comparisons between event rates of metal-on-metal hip resurfacing and THA are made using a quasilikelihood generalized linear model. We identified 7421 abstracts, screened and reviewed 384 full-text articles, and included 236. The most common study designs were prospective cohort studies (46.6%; n = 110) and retrospective studies (36%; n = 85). Few randomized controlled trials were included (7.2%; n = 17).

RESULTS

The average time to revision was 3.0 years for metal-on-metal hip resurfacing (95% CI, 2.95-3.1) versus 7.8 for THA (95% CI, 7.2-8.3). For all devices, revisions and reoperations were more frequent with metal-on-metal hip resurfacing than THA based on point estimates and CIs: 10.7 (95% CI, 10.1-11.3) versus 7.1 (95% CI, 6.7-7.6; p = 0.068), and 7.9 (95% CI, 5.4-11.3) versus 1.8 (95% CI, 1.3-2.2; p = 0.084) per 1000 person-years, respectively. This difference was consistent with three of four national joint replacement registries, but overall national joint replacement registries revision rates were lower than those reported in the literature. Dislocations were more frequent with THA than metal-on-metal hip resurfacing: 4.4 (95% CI, 4.2-4.6) versus 0.9 (95% CI, 0.6-1.2; p = 0.008) per 1000 person-years, respectively. Adverse event rates change when discontinued devices were included.

CONCLUSIONS

Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing, except when discontinued devices are removed from the analyses. Results from the literature may be misleading without consistent definitions, standardized outcome metrics, and accounting for device market status. This is important when clinicians are assessing and communicating patient risk and when selecting which device is most appropriate for individual patients.

Initial stability of press-fit acetabular components under rotational forces

The primary goal of this study was to determine the initial press-fit stability in acetabular components without screw fixation. Mechanical testing was performed with the implantation of press-fit acetabular components in cadaveric specimens. No significant difference was found in load to failure testing between 1 and 2 mm of under-reaming. However, there was significant variability in bending forces required to create 150 μm of micromotion ranging from 49.3 N to 214.4 N. This study shows that cups implanted in a press-fit fashion, which are felt to be clinically stable, have high degrees of variability in resisting load and may be at risk for loosening. There is a need for more objective intra-operative techniques to test cup stability.

Acetabular protrusio

There are few reports describing the technique of managing acetabular protrusio in primary total hip replacement. Most are small series with different methods of addressing the challenges of significant medial and proximal migration of the joint centre, deficient medial bone and reduced peripheral bony support to the acetabular component. We describe our technique and the clinical and radiological outcome of using impacted morsellised autograft with a porous-coated cementless cup in 30 primary THRs with mild (n = 8), moderate (n = 10) and severe (n = 12) grades of acetabular protrusio. The mean Harris hip score had improved from 52 pre-operatively to 85 at a mean follow-up of 4.2 years (2 to 10). At final follow-up, 27 hips (90%) had a good or excellent result, two (7%) had a fair result and one (3%) had a poor result. All bone grafts had united by the sixth post-operative month and none of the hips showed any radiological evidence of recurrence of protrusio, osteolysis or loosening. By using impacted morsellised autograft and cementless acetabular components it was possible to achieve restoration of hip mechanics, provide a biological solution to bone deficiency and ensure long-term fixation without recurrence in arthritic hips with protrusio undergoing THR.

Cite this article: Bone Joint J 2013;95-B, Supple A:37–40.

Outcomes at least 10 years after cemented PF® (Zimmer) total hip arthroplasty: 83 cases

INTRODUCTION

Cementless total hip arthroplasty (TKA) is gaining ground over cemented TKA. The objective of this study was to assess survival rates of a cemented THA implant (PF(®), Zimmer), after at least 10 years and to assess changes in acetabular bone structure.

MATERIAL AND METHODS

Eighty-three ceramic-on-polyethylene THA prostheses were implanted between 1998 and 2001. Clinical outcomes were assessed using the Harris hip score and Postel Merle d'Aubigné score. For each hip, radiographs were examined for acetabular radiolucent lines, geodes, and granulomas; in addition, changes in bone structure and trabeculae were assessed comparatively to the other hip and classified from no change to severe osteolysis. Changes in trabeculae served to assess the loads applied to the bone. Polyethylene wear was assessed using the Livermore method.

RESULTS

A single patient was lost to follow-up. At last follow-up, 16 patients had died and six were contacted and had not required revision surgery; the remaining 52 patients (59 THAs) were re-evaluated and none had evidence of loosening. The Harris hip score at last evaluation was 91.6 compared to 60.5 preoperatively. No hips had evidence of acetabular osteolysis. For two hips, the radiographs showed complete acetabular radiolucent lines less than 2mm in width, with no mobilisation. Trabecular distribution was homogeneous with no stress shielding. Mean annual rate of wear was 0.08mm. No instances of femoral component loosening were recorded; granulomas involving no more than five Gruën zones were seen in three cases.

DISCUSSION

This study confirms the reliability of cemented THA, with a 12-year survival rate of 98.3%, in keeping with earlier data. Thus, our results establish that cemented ceramic-on-polyethylene prostheses remain valid options for THA.

LEVEL OF EVIDENCE

IV.

Cemented polyethylene and cementless porous-coated acetabular components have similar outcomes at a mean of seven years after total hip replacement: a prospective randomised study

The aim of this prospective randomised study was to compare the clinical and radiological results of a cemented all-polyethylene Ultima acetabular component with those of a cementless porous-coated acetabular component (PFC) following total hip replacement (THR). A total of 287 patients received either a polyethylene acetabular component (group A) or a cobalt-chromium porous-coated component (group B) with an identical cemented femoral component and 28 mm cobalt-chromium head, thus making it the largest study of its type. Patients were evaluated radiologically and clinically using the Harris hip score (HHS). Group A comprised 183 patients (73 male, 110 female) with a mean age of 71.3 years (55 to 89). Group B comprised 104 patients (48 male, 56 female) with a mean age of 69.8 years (56 to 89). A total of 16 patients (13 in Group A, three in Group B) did not have post-operative data for analysis. The mean follow-up in group A was 7.52 years (0.4 to 15.0) and in Group B 7.87 years (0.5 to 14.0). At final follow-up the mean HHS was similar between groups A and B (74.5 (25 to 100) and 78.0 (37 to 100), respectively; p = 0.068). The total number of revisions for any cause was 28, 17 of which were in group A and 11 in group B. The ten-year survivorship was 86.8% (95% confidence interval (CI) 78.4 to 92.1) and 89.2% (95% CI 78.3 to 94.8) for groups A and B, respectively (log-rank p-value = 0.938). A total of 20 cemented and two cementless acetabular components had evidence of acetabular radiolucencies or acetabular component migration at last follow-up (p = 0.001). These results indicate that patients with a cemented all-polyethylene and cementless porous-coated polyethylene lined acetabular component have similar long-term clinical outcomes.

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.

The minimum 10-year results of a second-generation cementless acetabular shell with a polished inner surface

The purpose of this prospective study was to evaluate the minimum 10-year outcomes and survivorship of the Reflection shell with a polished inner surface and an improved locking mechanism. Three hundred sixty-three total hip replacements with a mean follow-up of 11.6 years (range, 10.0-15.1) were evaluated. The mean Harris Hip and WOMAC scores at last follow-up were 87 and 77, respectively. Four cups were revised: 2 for infection and 2 for aseptic loosening. Thirteen cases underwent liner exchange for wear. Radiographic review of remaining cups identified 8.8% with identifiable peri-acetabular osteolysis and no cases of loosening. The overall 10- and 15-year Kaplan-Meier survivorship was 94% and 90% for the total hip arthroplasty system while the survivorship of the shell remained 99.4% at 15 years.

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.

In vivo polyethylene wear of bilateral total hip replacements - cemented versus uncemented modular sockets

We assessed polyethylene wear and osteolysis in 15 patients (30 hips) undergoing staged bilateral total hip arthroplasties, who had a cemented arthroplasty on one side and a hybrid arthroplasty on the other. All factors apart from mode of acetabular component fixation were matched. Wear was measured radiographically using Livermore's technique. The mean clinical and radiological follow-up was 11.2 years for the cemented and 10.7 years for the hybrid arthroplasties. Mean annual linear wear rate was 0.09mm/year in the cemented sockets and 0.14mm/year in the uncemented sockets. This difference was statistically significant (p=0.03), confirming previous reports that the rate of polyethylene wear is increased in uncemented sockets. No periacetabular osteolysis was noted. Femoral osteolysis in zone 7 occurred in 3 hybrid arthroplasties. It appears not all patients are equally affected. These results are further discussed.

Is there evidence for a superior method of socket fixation in hip arthroplasty? A systematic review

PURPOSE

Total hip arthroplasty has been a very succesful orthopaedic procedure. The optimal fixation method of the acetabular component however, has not yet been defined.

METHODS

We performed a systematic review using the Medline and Embase databases to find evidence for the superiority of cemented or cementless acetabular components on short- and long-term clinical and radiological parameters. Methodological quality for randomised trials was assessed using the van Tulder checklist, and for the non randomised studies we used the Newcastle-Ottawa quality assessment scale.

RESULTS

Our search strategy revealed 16 randomised controlled trials (RCT) and 19 non RCT studies in which cemented and cementless acetabular components are compared. A best evidence analysis for complications, wear, osteolysis, migration and clinical scores showed no superiority for either cemented or cementless socket in the RCTs. A best evidence analysis for non RCT studies revealed better osteolysis, migration properties and aseptic loosening survival for cementless sockets; however, wear and overall survival favoured the cemented sockets.

CONCLUSIONS

We recommend that an orthopaedic surgeon should choose an established cemented or cementless socket for hip replacement based on patient characteristics, knowledge, experience and preference.

Revision following cemented and uncemented primary total hip replacement: a seven-year analysis from the New Zealand Joint Registry

We have reviewed the rate of revision of fully cemented, hybrid and uncemented primary total hip replacements (THRs) registered in the New Zealand Joint Registry between 1999 and December 2006 to determine whether there was any statistically significant difference in the early survival and reason for revision in these different types of fixation. The percentage rate of revision was calculated per 100 component years and compared with the reason for revision, the type of fixation and the age of the patients. Of the 42 665 primary THRs registered, 920 (2.16%) underwent revision requiring change of at least one component. Fully-cemented THRs had a lower rate of revision when considering all causes for failure (p < 0.001), but below the age of 65 years uncemented THRs had a lower rate (p < 0.01). The rate of revision of the acetabular component for aseptic loosening was less in the uncemented and hybrid groups compared with that in the fully cemented group (p < 0.001), and the rate of revision of cemented and uncemented femoral components was similar, except in patients over 75 years of age in whom revision of cemented femoral components was significantly less frequent (p < 0.02). Revision for infection was more common in patients aged below 65 years and in cemented and hybrid THRs compared with cementless THRs (p < 0.001). Dislocation was the most common cause of revision for all types of fixation and was more frequent in both uncemented acetabular groups (p < 0.001). The experience of the surgeon did not affect the findings. Although cemented THR had the lowest rate of revision for all causes in the short term (90 days), uncemented THR had the lowest rate of aseptic loosening in patients under 65 years of age and had rates comparable with international rates of aseptic loosening in those over 65 years.

Cemented and cementless total hip replacement. Critical analysis and comparison of clinical and radiological results of 182 cases operated in Al Razi Hospital, Kuwait

OBJECTIVE

In this study we present the results of a series of cemented Exeter and cementless Zweymuller implants.

SUBJECT AND METHODS

Eighty-seven cemented and 95 cementless hip replacements for different hip pathologies were followed for an average period of 36 months for cementless and 60 months for cemented cases. Clinical results were calculated using the Merle d'Aubigne score. The orientation of the prosthetic components and the fixation of the cup and stem were analyzed. The clinical and radiological results were compared using statistical methods.

RESULTS

In the average period of 36 months in cementless and 60 months in cemented hip replacements the clinical results improved significantly when compared with the preoperative score (p < 0.05). Sixty-seven cemented acetabular cups (77.1%) were in the desired position (30-50 degrees ) and 20 cemented cups (22.9%) were outside this range. Seventy-six cups (80%) were in the desired degree of abduction and 19 (20%) were outside this range. All cups except 1 were anteverted or neutral. Of the femoral stems, 173 were in the neutral position, 5 in the valgus and 4 in the varus position. Cemented cups were more commonly loose and cemented and cementless stems did equally well. No significant differences in rate of complications were found.

CONCLUSION

Cementless acetabular implants had better clinical results and a lower loosening rate at 3 years of follow-up compared to cemented implants at 5 years of follow-up. The cemented femoral implants were equally stable compared to the cementless ones.

Primary total hip arthroplasty in protrusio acetabuli using impacted morsellized bone grafting and cementless cups: a medium-term radiographic review

Thirty primary total hip arthroplasties were performed for protrusio acetabuli in 23 patients (mean age, 46 years) using impacted autologous bone grafting and a cementless porous-coated hemispheric cup without the use of metal cages or rings. At 2 to 10 years' follow-up (mean, 4.2 years), there was satisfactory radiographic evidence of consolidation of the graft in all cases. All acetabular components were considered to be stable with no instance of graft resorption. Clinical results were considered as excellent in 14 hips, good in 13 hips, fair in 2 hips, and poor in 1 hip. For younger patients with protrusio acetabuli, use of an uncemented porous-coated hemispheric cup with peripheral press-fit fixation and restoration of bone stock with impacted autologous bone grafting reflect a technically straightforward procedure that appears to give satisfactory medium-term results.

Factors affecting aseptic loosening of 4750 total hip arthroplasties: multivariate survival analysis

BACKGROUND

Total hip arthroplasty is a successful surgery, that fails at a rate of approximately 10% at ten years from surgery. Causes for failure are mainly aseptic loosening of one or both components partially due to wear of articular surfaces and partially to design. The present analysis aimed to identify risk factors and quantify their effects on aseptic failure.

METHODS

Multivariate survival analysis was applied to 4,750 primary total hip arthroplasties performed between 1995 and 2000.

RESULTS

The survival of the prosthesis is affected by gender, age, pathology, type of the prosthesis and skill of the. The worst conditions are male patients, younger than 40 years, affected by sequelae of congenital diseases, operated by a who performed less than 400 total hip artroplasty in the period. Furthermore, cemented cups and stems (less expensive) have a higher risk of failure compared with uncemented ones (more expensive).

CONCLUSION

The only variable that affects survival and that can be modified by is the type of prosthesis: a lower cost is associated to a higher risk. Results concerning the risk associated with cemented components are partially in disagreement with studies performed in countries where cemented prostheses are used more often than uncemented ones.

Late fiber metal shedding of the first and second-generation Harris Galante acetabular component. A report of 5 cases

Five patients presented with fiber metal mesh shedding of a Harris Galante II acetabular cup detected between 11 and 15 years after implantation. All patients presented with hip pain and 4 demonstrated gross acetabular loosening and fiber metal separation on preoperative radiographs. The remaining patient underwent revision surgery because of a liner dislodgment and had a radiographically well fixed shell. Loosening and fiber metal separation were detected intraoperatively. Scanning electron microscopy of the retrieved shells demonstrated isolated diffusion bonding marks in the areas where the mesh separated from the substrate and no evidence of corrosion. Progressive osteolysis in the iliac bone was evident in 4 of our cases. Progressive iliac osteolysis may lead to loss of bone support in well-fixed cups and excessive stresses transferred to the interface between the fiber metal mesh and the titanium substrate leading to the separation of the 2 layers. Fiber metal separation may contribute to long-term loosening in the Harris Galante acetabular component.

Comparison of cemented and uncemented fixation in total hip replacement: a meta-analysis

BACKGROUND

The choice of optimal implant fixation in total hip replacement (THR)--fixation with or without cement--has been the subject of much debate.

METHODS

We performed a systematic review and meta-analysis of the published literature comparing cemented and uncemented fixation in THR.

RESULTS

No advantage was found for either procedure when failure was defined as either: (A) revision of either or both components, or (B) revision of a specific component. No difference was seen between estimates from registry and single-center studies, or between randomized and non-randomized studies. Subgroup analysis of type A studies showed superior survival with cemented fixation in studies including patients of all ages as compared to those that only studied patients 55 years of age or younger. Among type B studies, cemented titanium stems and threaded cups were associated with poor survival. An association was found between difference in survival and year of publication, with uncemented fixation showing relative superiority over time.

INTERPRETATION

While the recent literature suggests that the performance of uncemented implants is improving, cemented fixation continues to outperform uncemented fixation in large subsets of study populations. Our findings summarize the best available evidence qualitatively and quantitatively and provide important information for future research.

Total hip arthroplasty in acetabular deficiency: experience in Al Razi Hospital, Kuwait

OBJECTIVE

To report clinical and radiological outcomes of cemented and cementless total hip arthroplasty for primary and secondary osteoarthritis with a deficiency of acetabular bone stock.

SUBJECT AND METHODS

Thirty-seven patients (16 male and 21 female) having 41 hips affected by primary and secondary acetabular bone stock defect that were operated using cemented (n = 25) and cementless (n = 16) hip replacement were followed for an average period of 37 (range 12-100) months. Bone defect was classified according to American Academy of Orthopedic Surgery criteria. Different types of bone graft techniques and metal reinforcements were used. Merle d'Aubigné clinical score was used to calculate clinical outcomes. Geometrical position of the acetabular component, cup integration, hip center and graft integration were assessed.

RESULTS

The mean clinical score improved significantly from 10.6 patients preoperatively to 16.7 patients postoperatively; 95% of the cups were in the desired position and were considered integrated and the bone graft remodeled in most cases. There were 2 deep infections, 1 dislocation and 2 cases of transient neurological deficit. No significant differences in final clinical and radiological outcomes, rate of loosening and rate of complications were found between cemented and cementless acetabular replacements.

CONCLUSION

The results show that reconstruction of acetabular bone deficiency can be accomplished with few complications using either a cemented or cementless acetabular component with or without grafting according to the clinical situation.

Reasons for revision hip surgery: a retrospective review

The purpose of this study was to determine the indications for contemporary revision hip surgery in a consecutive series of patients. We retrospectively reviewed the clinical records and radiographs of 439 revision hip surgeries done between 1996 and 2003. Fifty-five percent of the surgeries were for aseptic loosening, 14% were for instability, 13% were for osteolysis around a well-fixed implant, 7% were for infection, 5% were for periprosthetic fracture, 3% were for conversion of a hemiarthroplasty, 1% was for psoas impingement, 1% was for loose recalled implants, and 1% was for implant fracture. As expected, aseptic loosening was the most common reason for revision surgery. Instability was a common reason for early revision whereas revision for osteolysis around a well-fixed implant was a more common reason for late revision.

Results of uncemented cups: a critical appraisal at 15 years

One of the most important advances in total hip arthroplasty is the development of successful cementless acetabular components. Cemented acetabular components in older patients showed increasing loss of fixation after the first decade. Loosening commonly occurred during the first decade in young patients and after revision surgeries. Although some cementless designs failed, the hemispheric design with a porous exterior surface now is adopted widely. Assessment of acetabular reconstructions should be evaluated as primary operations in the older age group, primary operations in younger patients, and revisions. In all three categories, the cementless hemispheric design has proven remarkably successful. For example, a compilation of three reports on acetabular revisions using the HGP design revealed that by 12.5 years, only five of 263 shells required shell re-revision (2%). Periprosthetic osteolysis and dislocation are problems, but are being addressed by improved articulations and designs. These advances are remarkable in generating successful long-term acetabular reconstructions.

A multimodality regimen for deep venous thrombosis prophylaxis in total knee arthroplasty

Data indicate that deep venous thrombosis (DVT) occurs at the time of knee arthroplasty. Nevertheless, literature concerning DVT prophylaxis has only recently addressed this contention. This prospective study evaluated the efficacy of a perioperative prophylactic regimen. Between January 1996 and June 2001, 1,308 knees (964 surgeries) underwent total knee arthroplasty. Patients were treated routinely with intraoperative heparin (1000 units intravenous push before inflation of the tourniquet and 500 units at deflation), hypotensive epidural anesthesia (MAP 70-90), external pneumatic compression boots, and aspirin (325 mg, PO, BID for 6 weeks). Duplex venous ultrasonography was performed before discharge. DVT was detected in 4% of cases (1% proximal and 3% distal). Bleeding complications occurred in 1%, and perioperative medical complications occurred in 12%.

The optimal fixation of the cementless acetabular component in primary total hip arthroplasty

The optimal fixation of the acetabular component in primary total hip arthroplasty remains controversial. Long-term follow-up studies show that significant loosening rates occur with cemented acetabular components and that these problems persist despite attempts to improve cementing technique. Cementless acetabular components that rely on biologic fixation can have lower rates of radiographic loosening at 10 years compared with cemented acetabular components. Although revision rates for both modes of fixation are largely equivalent at 10 years, the superior radiographic performance of cementless acetabular components at 10 years suggests that biologic fixation through bone ingrowth may provide more durable long-term implant survival compared with cemented fixation. Osteolysis is the major obstacle to long-term cementless acetabular component survival. Potential future options that may inhibit osteolysis include decreasing bone resorption that results from debris-stimulated foreign body response through the use of medications; decreasing the number of particles generated by using alternative bearing surfaces; and improving bone ingrowth, particularly through the use of growth factors and improved implant materials and designs.