The Morscher Press Fit acetabular component: a nine- to 13-year review

Forged to heal: The role of metallic cellular solids in bone tissue engineering

Metallic cellular solids, made of biocompatible alloys like titanium, stainless steel, or cobalt-chromium, have gained attention for their mechanical strength, reliability, and biocompatibility. These three-dimensional structures provide support and aid tissue regeneration in orthopedic implants, cardiovascular stents, and other tissue engineering cellular solids. The design and material chemistry of metallic cellular solids play crucial roles in their performance: factors such as porosity, pore size, and surface roughness influence nutrient transport, cell attachment, and mechanical stability, while their microstructure imparts strength, durability and flexibility. Various techniques, including additive manufacturing and conventional fabrication methods, are utilized for producing metallic biomedical cellular solids, each offering distinct advantages and drawbacks that must be considered for optimal design and manufacturing. The combination of mechanical properties and biocompatibility makes metallic cellular solids superior to their ceramic and polymeric counterparts in most load bearing applications, in particular under cyclic fatigue conditions, and more in general in application that require long term reliability. Although challenges remain, such as reducing the production times and the associated costs or increasing the array of available materials, metallic cellular solids showed excellent long-term reliability, with high survival rates even in long term follow-ups.

Wear Risk Prevention and Reduction in Total Hip Arthroplasty. A Personalized Study Comparing Cement and Cementless Fixation Techniques Employing Finite Element Analysis

The wear rate on Total Hip Arthroplasty (THA) entails a heavy burden for patients. This becomes more relevant with increased wear risk and its consequences such as osteolysis. In addition, osteolysis has been described in cemented and uncemented acetabular implants, and nowadays, controversy remains as to whether or not to cement the acetabular component. A personalized theoretical study was carried out to investigate which parameters have an influence on wear risk and to determine the best fixation method. Liner wear risk was assessed for two different types of fixation (cemented vs uncemented) through Finite Elements Analysis (FEA). The intraoperative variables used to determine the wear risk (cervical-diaphyseal angle, Center of Rotation positioning -COR-, head material, head size, and liner thickness) are vital parameters in surgical planning. Two types of tridimensional liner models of Ultra High Molecular Weight Polyethene (UHMWPE) were simulated through finite element analysis (FEA-over 216 cases were the core of this research). A significant relationship was found between the cervical-diaphyseal angle and wear risk (p < 0.0001), especially in valgus morphology. The acetabular fixation technique (p < 0.0001) and liner thickness (p < 0.0001) showed a significant relationship with wear risk. According to our study, using a cemented fixation with a thick liner in the right center of rotation appears to be the proper stratagy for preventing polyethylene liner wear.

Survival of monoblock RM vitamys compared with modular PINNACLE cups: mid-term outcomes of 200 hips performed by a single surgeon

INTRODUCTION

Monoblock cups have theoretical advantages over modular cups; however, their superiority in terms of survival has not been confirmed in comparative studies.

METHODS

We compared the mid-term survivorship of 107 RM Pressfit vitamys monoblock cups (Mathys Ltd., Bettlach, Switzerland) with 93 modular pressfit Pinnacle cups (DePuy Synthes, Warsaw, IN, USA). All cases were registered in the Arthroplasty Registry Thessaloniki and performed by a senior surgeon through the same approach between 2013 and 2014. The groups were comparable in sex distribution, preoperative diagnosis, follow-up, cup diameter, head diameter, type and use of screws, HOOS and HSS preop scores; the recipients of RM cup were significantly younger.

RESULTS

3 sockets were revised. The 6-year survival for any reason was 99.1% for the RM and 97.8 % for the PINNACLE group. There was no difference in survival for aseptic loosening and any reason between groups (log-rank test p = 0.921 and p = 0.483, respectively). The age (95% CI, 0.79-1.1), sex (95% CI, 0.2-45.0), cup diameter (95% CI, 0.18-1.1), head diameter (95% CI, 0.004-6.2), preoperative diagnosis and use of screws (95% CI, 0.02-4.3), did not influence hazard ratio for revision between groups. HHS and HOOS were comparable at the last follow-up.

CONCLUSIONS

Our study demonstrated that both cup designs had similar revision rates at mid-term follow-up, regardless the fact that the RM vitamys was used in a cohort of younger patients; which according to the literature would have led to earlier failures. Further long-term data are needed to evaluate the superiority of RM vitamys in the clinical setting, especially in the young.

A vitamin E blended highly cross-linked polyethylene acetabular cup results in less wear: 6-year results of a randomized controlled trial in 199 patients

Background and purpose - Survivorship of total hip arthroplasty (THA) with the ultra-high molecular weight polyethylene (UHMWPE) monoblock cup has been limited due to periprosthetic osteolysis and aseptic loosening, secondary to wear of the UHMWPE. In response, a vitamin E blended highly cross-linked polyethylene (HXLPE) cup was developed. This study set out to compare the wear and clinical 6-year outcomes of vitamin E blended HXLPE with UHMWPE in an isoelastic monoblock cup in patients with hip osteoarthritis who underwent uncemented THA. The 2-year results have been reported previously. Patients and methods - For this randomized controlled trial 199 patients were included. 102 patients received the vitamin E blended HXLPE uncemented acetabular cup and 97 patients the uncemented UHMWPE monoblock cup. Clinical and radiographic parameters were obtained preoperatively, directly postoperatively, and at 3, 12, 24, and 72 months. Wear rates were compared using the femoral head penetration (FHP) rate. Results - 173 patients (87%) completed the 6-year follow-up. The mean NRS scores for rest pain, load pain, and patient satisfaction were 0.3 (SD 1), 0.6 (SD 1), and 8.6 (SD 1) respectively. The mean Harris Hip Score was 93 (SD 12). The FHP rate was lower in the vitamin E blended HXLPE cup (0.028 mm/year) compared with the UHMWPE cup (0.035 mm/year) (p = 0.002). No adverse reactions associated with the clinical application of vitamin E blended HXLPE were observed. 15 complications occurred, equally distributed between the two cups. The 6-year survival to revision rate was 98% for both cups. There was no aseptic loosening. Interpretation - This study shows the superior performance of the HXLPE blended with vitamin E acetabular cup with clinical and radiographic results similar to the UHMWPE acetabular cup.

Long-Term Results of Total Hip Arthroplasty with RM Classic Cups

Relevance. The RM Classic monoblock titanium-coated polyethylene cup is widely used in the total hip arthroplasty. However, so far in Russia there has been no analysis of follow-up over 10 years for a limited number of patients in a single hospital. The aim of the study was to evaluate the long-term outcomes of total hip replacement with RM Classic acetabular component. Materials and Methods. The outcomes of 328 total hip arthroplasties (289 patients operated in the period from 1997 to 2007) with RM Classic cups were evaluated in a monocentral retrospective clinical study. The average follow-up period was 14.4 years. Revision procedure due to aseptic loosening, polyethylene wear or osteolysis was considered as the end point of the study. Results. 9 revisions during the short and medium follow-up periods (up to 10 years) were associated with malpositioning of RM Classic components and errors in surgical technique. The indications for later revision THA (19 cases) were polyethylene wear and aseptic loosening. Only in one case they were combined with pelvic bone osteolysis with the formation of III a defect according to W.G. Paprosky classification. Within 15 years the Kaplan-Meier survivorship of RM Classic cup was 92.5%. There was a statistically significant difference of the survival curves in the ceramic-on-poly against metal-on-poly bearings: 94.9% and 79.4%, respectively. The average Harris Hip Score was 88.6. Conclusion. RM Classic uncemented monoblock cup has proven its high efficiency and survival in 15 years follow-up period and over.

Survivorship of a Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty With a Mean Follow-Up of 18 Years

BACKGROUND

The use of porous tantalum for the acetabular component in primary total hip arthroplasty (THA) has demonstrated excellent short-term and midterm results. However, long-term data are scarce. The purpose of this prospective study is to report the long-term clinical and radiologic outcome following use of an uncemented porous tantalum acetabular component in primary THA with a minimum follow-up of 17.5 years, in a previously studied cohort of patients.

METHODS

We prospectively followed 128 consecutive primary THAs in 140 patients, between November 1997 and June 1999. A press-fit porous tantalum monoblock acetabular component was used in all cases. All patients were followed clinically and radiographically for a mean of 18.1 years (range, 17.5-19 years).

RESULTS

Mean age of patients at the time of operation was 60.4 years. Harris hip score, Oxford hip score, and range of motion were dramatically improved in all cases (P < .001). At last follow-up, all cups were radiographically stable with no evidence of migration, gross polyethylene wear, progressive radiolucencies, osteolytic lesions, or acetabular fractures. The survivorship with reoperation for any reason as end point was 92.8% and the survivorship for aseptic loosening as an end point was 100%.

CONCLUSION

The porous tantalum monoblock cup in primary THA demonstrated excellent clinical and radiographic outcomes with no failures because of aseptic loosening at a mean follow-up of 18.1 years.

The Morscher Press-Fit Acetabular Component: An Independent Long-Term Review at 18-22 Years

BACKGROUND

There are relatively few 20-year results of uncemented acetabular components, and most of these are modular designs. This study reports the 20-year results of a monoblock press-fit acetabular component.

METHODS

A total of 122 total hip arthroplasties (111 patients) using the Morscher cup were reviewed at a mean of 19.7 years. The average age at implantation was 57.3 years (range, 36-74 years), and 81 (66%) were men.

RESULTS

Twenty-two patients (25 hips) had died. Seven hips were revised, including 5 acetabular revisions. Six patients (6 hips) declined to participate but were known not to have been revised. The mean Oxford hip score was 41.1 (range, 22-48), and the mean reduced Western Ontario and McMaster Universities Osteoarthritis Index score was 5.7/48 (range, 0-24). Eccentric wear was seen in 13 (15.7%) and major osteolysis in 14 (17%) of 82 surviving hips with radiographs. The all-cause revision rate was 0.32 per 100 observed component years (95% confidence interval [CI], 0.13-0.66). The 20-year Kaplan-Meier survival was 93.4% (CI, 86.6-96.8) for all-cause revisions, 95.5% (CI, 89.4-98.1) for any acetabular revision, and 97.1% (CI, 91.2-99.1) for acetabular aseptic loosening, wear, or osteolysis.

CONCLUSION

The Morscher acetabular component has continued to perform well at 20 years despite using conventional polyethylene with results that match or surpass other cementless acetabulae.

The RM Pressfit vitamys: 5-year Swiss experience of the first 100 cups

BACKGROUND

The RM Pressfit vitamys is a titanium particle-coated monoblock cup with vitamin E stabilised highly cross-linked polyethylene. Initial fixation is achieved via press-fit with subsequent stability by bone on-growth. This is the first study to report the 5-year results of this design.

METHODS

We performed a prospective cohort study according to STROBE guidelines of 100 consecutive total hip replacements (THRs) in 92 patients all with ceramic heads. Demographic data, pre/postoperative visual analogue scale (VAS) for pain and satisfaction, Harris Hip Scores (HHS) and complications were recorded. Radiographic analysis of osteolysis and loosening was complemented by EBRA (Einzel-Bild-Röntgen-Analyse) evaluation of cup movement.

RESULTS

Our cohort comprised 48 women (mean age 67; SD 10.4) and 44 men (mean age 69; SD 7.8). The mean body mass index was 27 kg/m2 (SD 4.6). Surgical indications were osteoarthritis 96%, avascular necrosis 3% and fracture 1%. 82% had a direct anterior approach, 15% anterolateral and 3% trans-gluteal. 4 surgeons were involved. 1 cup was repositioned and fixed with screws within a week of index surgery. There were 2 intraoperative femoral fractures, 3 haematomata with 1 requiring drainage and 1 deep infection settling with an open washout and modular exchange. Mean VAS satisfaction increased from 3.8 (SD 2.0) to 8.8 at 6 weeks (SD 1.4) and 9.5 (SD 1.3) at 5 years. The HHS functional scores were 58.9 (SD 13.2) preoperatively and 94.6 (SD 6.6) at 5 years. Radiographic analysis showed neither progressive radiolucency nor osteolysis. Mean migration was 1.5 mm after 5 years.

CONCLUSIONS

Mid-term results of the RM Pressfit vitamys cup are encouraging.

Long-Term Clinical and Radiographic Outcomes of Porous Tantalum Monoblock Acetabular Component in Primary Hip Arthroplasty: A Minimum of 15-Year Follow-Up

BACKGROUND

The porous tantalum monoblock cup has demonstrated excellent short-term and midterm clinical and radiographic outcomes in primary THA, but longer follow-up is necessary to confirm the durability of these results into the second decade. The purpose of this study is to report the clinical and radiographic outcomes for this monoblock cup with a minimum 15-year follow-up.

METHODS

From June 1998 to December 1999, 61 consecutive patients (63 hips) underwent primary THA with a tantalum monoblock acetabular component. All patients were followed clinically and radiographically for a minimum of 15 years. At a mean of 15.6 years (range, 15-16 years) of follow-up, 5 patients had died, and 4 had been lost to follow-up, leaving 52 patients (54 hips) for analysis. The underlying diagnosis that led to the primary THA was primary osteoarthritis in 43 hips, avascular necrosis in 4, developmental hip dysplasia in 3, rheumatoid arthritis in 3 and post-traumatic osteoarthritis in 1.

RESULTS

One cup was revised for deep infection; at surgery, the cup showed osseointegration. At a mean follow-up of 15.6 years (range, 15-16 years), the survivorship with cup revision for aseptic loosening as end point was 100%. There was no radiographic evidence of loosening, migration, or gross polyethylene wear at last follow-up. The mean Harris Hip Scores improved from 47 points preoperatively to 94 points.

CONCLUSION

The porous tantalum monoblock cup in primary THA demonstrated excellent clinical and radiographic outcomes with no failures because of osteolysis or loosening at a minimum follow-up of 15 years.

Which implant should we use for primary total hip replacement? A systematic review and meta-analysis

BACKGROUND

Many total hip implants are currently available on the market worldwide. We aimed to estimate the probability of revision surgery at ten years for each individual total hip implant and to compare these estimates with the National Institute for Health and Care Excellence (NICE) benchmark.

METHODS

We performed a meta-analysis of cohort studies. The methodological quality was assessed with use of the Assessment of Quality in Lower Limb Arthroplasty (AQUILA) checklist. We searched PubMed, Embase, Web of Science, and the Cochrane Library. Additionally, national joint registries that were full members of the International Society of Arthroplasty Registers (ISAR) were hand searched. Studies in which the authors reported the survival probability for either the acetabular or the femoral component of primary total hip replacements with use of revision for any reason or for aseptic loosening at ten years as the end point, with at least 100 implants at baseline, and in which at least 60% of the patients had primary osteoarthritis were eligible for inclusion.

RESULTS

The search strategy revealed 5513 papers describing survival probabilities for thirty-four types of acetabular components and thirty-two types of femoral components. Eight types of acetabular cups and fifteen types of femoral stems performed better than the NICE benchmark.

CONCLUSIONS

We recommend that surgeons performing a primary total hip replacement use an implant that outperforms the NICE benchmarks.

Survival outcomes of cemented compared to uncemented stems in primary total hip replacement

Total hip replacement (THR) is a successful and reliable operation for both relieving pain and improving function in patients who are disabled with end stage arthritis. The ageing population is predicted to significantly increase the requirement for THR in patients who have a higher functional demand than those of the past. Uncemented THR was introduced to improve the long term results and in particular the results in younger, higher functioning patients. There has been controversy about the value of uncemented compared to cemented THR although there has been a world-wide trend towards uncemented fixation. Uncemented acetabular fixation has gained wide acceptance, as seen in the increasing number of hybrid THR in joint registries, but there remains debate about the best mode of femoral fixation. In this article we review the history and current world-wide registry data, with an in-depth analysis of the New Zealand Joint Registry, to determine the results of uncemented femoral fixation in an attempt to provide an evidence-based answer as to the value of this form of fixation.

Clinical and Radiographic Outcomes with a Hydroxyapatite and Porous Coated Cup Design

Press-fit, hydroxyapatite-coated acetabular cup designs may offer a lower incidence of loosening and migration than older designs. Our study evaluated the initial clinical and radiographic success of a cementless acetabular shell in a large cohort of primary total hip arthroplasty (THA) patients. We queried our institution’s prospectively collected registry for a series of 771 primary THAs (695 patients) implanted with this cup by 4 high-volume arthroplasty surgeons. Of the 613 hips with minimum 2-year followup, average HHS (Harris Hip Score) was 93.6, WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) was 87.6, and VAS (Visual Analog Scale) pain score was 1.2. While there was a 2% reoperation rate (12 hips), none of the cups were revised for aseptic loosening. No radiolucencies were found and there was no evidence of acetabular loosening. At early followup, this newer cementless acetabular cup implant design exhibits high survivorship and clinical success.

Do monoblock cups improve survivorship, decrease wear, or reduce osteolysis in uncemented total hip arthroplasty?

BACKGROUND

Monoblock acetabular components used in uncemented total hip arthroplasty (THA) have certain mechanical characteristics that potentially reduce acetabular osteolysis and polyethylene wear. However, the degree to which they achieve this goal is not well documented.

QUESTIONS/PURPOSES

The purpose of this study was to use a systematic review of controlled trials to test the hypothesis that monoblock cups have superior (1) polyethylene wear rate; (2) frequency of cup migration; (3) frequency of acetabular osteolysis; and (4) frequency of aseptic loosening compared with modular components used in uncemented THA.

METHODS

A systematic search was conducted in the Medline, Embase, and Cochrane electronic databases to assemble all controlled trials comparing monoblock with modular uncemented acetabular components in primary THA. Included studies were considered "best evidence" if the quality score was either ≥ 50% on the Cochrane Back Review Group checklist or ≥ 75% the Newcastle-Ottawa quality assessment scale. A total of seven publications met our inclusion criteria.

RESULTS

Best evidence analysis showed no difference in polyethylene wear rate, the frequency of cup migration, and aseptic loosening between monoblock and modular acetabular components. No convincing evidence was found for the claim that lower frequencies of acetabular osteolysis are observed with the use of monoblock cups compared with modular uncemented cups.

CONCLUSIONS

The purported benefits of monoblock cups were not substantiated by this systematic review of controlled studies in that polyethylene wear rates and frequencies of cup failure and acetabular osteolysis were similar to those observed with modular implants. Other factors should therefore drive implant selection in cementless THA.

Statins may reduce femoral osteolysis in patients with total Hip arthroplasty

In experimental studies, statin use has been associated with reduction of osteoclastic activity and promotion of bone formation around implants. Moreover, a large clinical study recently reported a substantially reduced risk of revision for aseptic loosening among statin users with THA. Our objective was to evaluate the influence of statin use on the development of femoral osteolysis within 5 years after THA. We conducted a case-cohort study including all THAs presenting with femoral osteolysis at the 5 year visit (cases) and compared them with those without osteolysis (controls). Cases and controls were identified from a cohort of primary THAs operated between 2001 and 2005. Seven hundred thirty-five THAs were included, mean age 68 years. Five years after surgery osteolysis had developed around the femoral component of 40 THAs (5.4%). Ever-use of statins was much less frequent among cases (5 of 40, 12.5%) than among controls (199 of 695, 28.6%). The crude risk ratio of femoral osteolysis among statin users was 0.36 (95% CI 0.14; 0.92). After adjusting for age, sex, activity level, BMI, diagnosis, bearing surface, and type of stem, the adjusted risk ratio was 0.38 (95% CI 0.15; 0.99). In conclusion, statin use was associated with a reduced risk of developing femoral osteolysis 5 years after THA. Statins may be useful for reducing the risk of implant failure following THA.

Survival of uncemented acetabular monoblock cups: evaluation of 210 hips in the Swedish Hip Arthroplasty Register

BACKGROUND AND PURPOSE

Monoblock acetabular cups represent a subtype of uncemented cups with the polyethylene liner molded into a metal shell, thus eliminating-or at least minimizing-potential backside wear. We hypothesized that the use of monoblock cups could reduce the incidence of osteolysis and aseptic loosening, and thus improve survival compared to modular designs.

PATIENTS AND METHODS

We identified all 210 primary total hip arthroplasty (THA) procedures in the Swedish Hip Arthroplasty Register that used uncemented monoblock cups during the period 1999-2010. Kaplan-Meier and Cox regression analyses with adjustment for age, sex, and other variables were used to calculate survival rates and adjusted hazard ratios (HRs) of the revision risk for any reason. 1,130 modular cups, inserted during the same time period, were used as a control group.

RESULTS

There was a nearly equal sex distribution in both groups. Median age at the index operation was 47 years in the monoblock group and 56 years in the control group (p < 0.001). The cumulative 5-year survival with any revision as the endpoint was 95% (95% CI: 91-98) for monoblock cups and 97% (CI: 96-98) for modular cups (p = 0.6). The adjusted HR for revision of monoblock cups compared to modular cups was 2 (CI: 0.8-6; p = 0.1). The use of 28-mm prosthesis heads rather than 22-mm heads reduced the risk of cup revision (HR = 0.2, CI: 0.1-0.5; p = 0.001).

INTERPRETATION

Both cups showed good medium-term survival rates. There was no statistically significant difference in revision risk between the cup designs. Further review of the current patient population is warranted to determine the long-term durability and risk of revision of monoblock cup designs.

Ten-year results with the Morscher press-fit cup: an uncemented, non-modular, porous-coated cup inserted without screws

Total hip arthroplasty (THA) with well designed cementless acetabular implants has shown excellent results. The purpose of this study was to assess our clinical and radiological outcomes using an uncemented cup. We conducted a prospective cohort study including all consecutive primary THAs performed with the Morscher press-fit cup, an uncemented non-modular acetabular component, between March 1996 and December 1998. Patients were evaluated at ten years with clinical and radiological follow-up, patient satisfaction and questionnaire assessment using the Harris hip score (HHS), Merle d'Aubigné and Postel score, the UCLA score, the 12-item short-form health survey (SF-12) and a visual analog scale. Five hundred sixty-one THAs were performed in 518 patients. At 120 months (± 7.3 months), 303 patients with 335 THAs were still available for follow-up. None of the patients had required cup revision for aseptic loosening. At ten years, the cup survivorship was 98.8% (95% CI 97.4-99.5) with cup revision for any cause as an endpoint. No radiolucencies were seen around the cups, but osteolytic defects involved 21 stems (8.3%). Mean total linear polyethylene wear was 0.9 mm. The Morscher acetabular replacement cup provides excellent results at ten years. There were no revisions for aseptic loosening of the cup, and no osteolytic defects were found around the cup. Patient satisfaction was high and the clinical results were very good.

Metal-backed acetabular components with conventional polyethylene: a review of 9113 primary components with a follow-up of 20 years

The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components. A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis. Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups. Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.

Uncemented and cemented primary total hip arthroplasty in the Swedish Hip Arthroplasty Register

BACKGROUND AND PURPOSE

Since the introduction of total hip arthroplasty (THA) in Sweden, both components have most commonly been cemented. A decade ago the frequency of uncemented fixation started to increase, and this change in practice has continued. We therefore analyzed implant survival of cemented and uncemented THA, and whether the modes of failure differ between the two methods of fixation.

PATIENTS AND METHODS

All patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 who received either totally cemented or totally uncemented THA were identified (n = 170,413). Kaplan-Meier survival analysis with revision of any component, and for any reason, as the endpoints was performed. Cox regression models were used to calculate risk ratios (RRs) for revision for various reasons, adjusted for sex, age, and primary diagnosis.

RESULTS

Revision-free 10-year survival of uncemented THA was lower than that of cemented THA (85% vs. 94%, p < 0.001). No age or diagnosis groups benefited from the use of uncemented fixation. Cox regression analysis confirmed that uncemented THA had a higher risk of revision for any reason (RR = 1.5, 95% CI: 1.4-1.6) and for aseptic loosening (RR = 1.5, CI: 1.3-1.6). Uncemented cup components had a higher risk of cup revision due to aseptic loosening (RR = 1.8, CI: 1.6-2.0), whereas uncemented stem components had a lower risk of stem revision due to aseptic loosening (RR = 0.4, CI: 0.3-0.5) when compared to cemented components. Uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 postoperative years than cemented stems (RR = 8, CI: 5-14). The 5 most common uncemented cups had no increased risk of revision for any reason when compared with the 5 most commonly used cemented cups (RR = 0.9, CI: 0.6-1.1). There was no significant difference in the risk of revision due to infection between cemented and uncemented THA.

INTERPRETATION

Survival of uncemented THA is inferior to that of cemented THA, and this appears to be mainly related to poorer performance of uncemented cups. Uncemented stems perform better than cemented stems; however, unrecognized intraoperative femoral fractures may be an important reason for early failure of uncemented stems. The risk of revision of the most common uncemented cup designs is similar to that of cemented cups, indicating that some of the problems with uncemented cup fixation may have been solved.