in 27.7% and proximally migrated femur in 5.5%. Acetabular obstacles included protrusio acetabuli in. 14.8% and structural posterior acetabular bone defect.
The results of primary total hip arthroplasty for sub-capital femoral neck fracture in previously normal hips are reported. Thirty-seven patients aged 70 or less at ...
biocompatible is the titanium alloy extra low interstitial (ELI)2 Tiâ6Alâ4V; its composi- tion is 90 wt% Ti, 6 wt% Al, and 4 wt% V. The optimal properties for this material are produced by hot forging; any subsequent deformation and/or heat treat
and the types of arthroplasty performed are shown in Tables. II and ... arthroplasties performed. Number of ..... in all 12 a Girdlestone arthroplasty was performed.
Gonzalez Della Valle A, Serota A, Go G, Sorriaux G, Sculco TP, Sharrock NE, et al. Venous thromboembolism .... Yu HT, Dylan ML, Lin J, Dubois RW. Hospitals' ...
Abstract: Instability after total hip arthroplasty (THA) is not a rare occurrence. Numerous factors have been associated with dislocation including surgical approach, implant design, failure to restore proper hip mechanics and soft tissue restraints,
V early osteointegration. On-growth of bone to porous coated prostheses is ... rich femoral component or with the ce- ... total hip arthroplasty in dogs (1, 2). Loo-.
Radiological analysis assessing heterotopic ossification, femoral osteolysis and femoral stem ... following total joint replacement.12 A retrospec- tive study by ...
Total hip replacement (THR) is a very common procedure undertaken in up to 285 000 .... diagnosis can include activity-related pain, aseptic loosening,.
an ideal total hip replacement with a large femoral head and a high head-neck ratio. B: Cam-type impingement in the native hip caused by a reduced femoral head-neck offset and similar impingement in a prosthetic hip with a small femoral head and a sk
575. INTRODUCTION. Total hip replacement (THR) provides a very effective ... arthroplasty, bilateral arthroplasty; those transferred or initially treated at other ...
of complications after internal fixation or hemiarthroplasty. To avoid some of these complications we have used primary total hip replacement for independently.
Total. 91. RESU. LTS. The 107 patients had 112 hip replacements; .... fixation versus hemiarthroplasty for the displaced subcapital fracture of the femur:.
axis robotic arm with a high speed milling de- vice as an end .... pain and better function than dogs operated on without using the .... 93 hips (48 [email protected] and 45 control) .... in centimeters minus 100 = kilograms) and age. The cutoff age ...
THE JOURNAL OF BONE AND JOINT SURGERY hemiarthroplasty or revision hip arthroplasty were excluded. A total of 99 patients presented with 101 first-.
Nov 7, 2006 - Post-operative pain management after joint replacement surgery is important for patients' .... Sciatic nerve blocks were only used in few patients.
femoral rollback to occur. By not ârolling back,â the posterior femoral metaphysis in a total condylar knee impinged against the tibial articular surface at approxi-.
Department of Trauma and Orthopaedic Surgery, Medical School, Uni- versity of Newcastle upon Tyne, Newcastle upon Tyne ... age orthopaedic surgeon in a non-specialist hospital is not known. The published data from the Norwegian and ..... 1. Medical D
Despite the current success of total hip replacement, we continue to strive for improvements, particularly in the durability or survivorship of the components,.
May 30, 2016 - introduction: In the Middle East, severe developmental dysplasia of the hip with subsequent high dislocation is often seen. We assessed the ...
stable (greater than the control) when walking over barriers as was roll for the sit-to-stand task, indicative of ... after total hip replacement regarding the risk of a fall, especially in the elderly. Most patients ... metre cable to a computer whi
resulting in deformities, protrusio acetabuli and malalignment of the limbs. Ligamentous laxity is seen frequently. In the past few decades there has been an ...
primary total hip replacements and 11 were revision operations, with aseptic loosening of the original implant being the main indication for revision. The.
TOTAL HIP REPLACEMENT?
D. W. MURRAY, A. J. CARR, C. J. BLJLSTRODE
From the Nuffield Orthopaedic Centre, Oxford, England
To assist surgeons to select a total hip replacement (THR) we present comparative information on all such
implants on the market in the UK. We identified 62 different primary THRS, manufactured
in the last five years, and only 30% have any
results published in peer-reviewed journals. The prices range from Â£250to Â£2000,and the two cheapest implants
have the longest
are performed annually in the UK (Williams et al 1992) and the number is increasing (Buistrode and Murray 1992). It is therefore important that only long-lasting and reliable implants
Many new designs of THR have been introduced in recent years. Most will have been tested in a laboratory, but unlike new drugs, there is at present no formal requirement for clinical tests before a new design is available for sale on the open market. The introduction of the new European CE
The number of THR implants availablein the UK, mark may make clinical trials mandatory (Council Direc and presumably the rest of the world, is rapidly tive 93/42/EEC 1993), but the results of such trials may be increasing, but there is little or no scientific evidence that the newer, more expensive, implants are better than established designs. Some will undoubtedly be worse.
We believe that this situation is unsatisfactoryand make
that preference be given to implants with good results in
publishedpeer-reviewedlong-termclinicaltrials. J Bone Joint Surg [Br] 1995;77-B:520-7. Received 21 July 1994; Accepted 20 October 1994
difficult to interpret. Early overall assessments are usually carried out with clinical scoring systems based on relief of pain and improvement in function and movement (Murray 1993). There are, however, a number of different scoring
systems in use and these
cannot be directly compared
(Bryant et al 1993). Long-term outcome is usually meas ured as time to revision, using survival analysis. This too is liable to distortion which makes comparison of outcome difficult (Murray, Carr and Bulstrode 1993).
Our aim was to reviewall the designsof THR available in the UK, and to assess how much is known about their clinical
Total hip replacement (THR) is a very successful operation; about 40 000 are carried out annually in the UK (Williams et al 1992). The published results suggest that for most implants the revision rate is about 10% at ten years (Ritter and Campbell 1987; Roberts, Finlayson and Freeman 1987; Wilson-MacDonald and Morscher 1990; Malchau, Herberts and Ahnfelt 1993; Schulte et al 1993; Alsema, Deutman and Mulder 1994). Some designs have good results at five years but may develop high failure rates by ten years (Malchau et al 1993; Owen et al 1994). The cost of the
METHOD In 1994 we identified all manufacturers and distributors of hip implants in the UK and requested specific information about all the primary THR prostheses that they were sell ing. They were asked to provide the date of release on to the market, the estimated market share, the cost, the design features and references for any published clinical results. These and other references related to the implants were
primary implant is only a small proportion of the total cost of the operation. Revision operations cost more and do not
critically reviewed and summarised. The information was collated in a table and sent back to the distributor or
give as good a functional result or last as long as a primary THR (Kershaw et al 1991). About 5000 revisions of THR
manufacturer who was asked to check the information and suggest any corrections or additions which were necessary.
20%, >20%. Cost(12). This is the cost in Â£sterling for the complete THR
in the form most commonly used in the UK for primary THR. It includes the femoral component, the head and the acetabular component. Fixation. This determines whether cemented, cementless or both. Design features. This section was restricted to 25 words; it describes important design features, information about materials, and whether the implant has been derived from another design. Clinical results. We considered only those published in peer-reviewed journals relating to either clinical function or implant survival. If none of these was found, we state â€˜no published results' . We selected representative series for each THR, but excluded all results relating to fracture treatment. < 5-year
and > 5-year
only series of at least ten THRs which have been assessed
for pain and function and followed either for less or more than five years. We recorded the results as good if the scoring system being used gave an average result described as good or excellent. [email protected][email protected] 15-year survival analysis. These include survival analyses with ten or more patients at risk in the year of analysis.
survival analyses was revision, or symptoms severe enough to warrant revision. If the analysis related to a specific use
20%. The information about market share may not be reliable: manufacturers were unwilling to give this informa tion, but it can be obtained from other sources (Newman 1993). The prices ranged from Â£250to Â£2000.Most, if not all, manufacturers offer discounts but no useful information was available on this. The prices in other countries are often different from UK prices because of factors such as distribution costs. Some 29 of the THRs (47%) are designed to be cemented (price Â£250to Â£750);nine (15%) can be either cemented or cementless (price Â£355to Â£1250) and 24 (39%) are for cementless use ([email protected] to Â£2000).
Advertising for each of the implants claims a unique combination of features which make them better than other previously
are said to
be based on an implant that has previously been shown to be successful. Five femoral stems were monobloc, six were either modular or monobloc, and the remainder were modular. There are reports of five-year survival results in peer reviewed journals for only eight implants. For three implants (Charnley, Stanmore and MUller), there are ten year survival results, for two (Charnley and Stanmore) 15-year survival results, and for only one (Charnley) are there 20-year results. Only nine implants have any reports of results for longer than a five-year follow-up, and only 30% have any results whatsoever published in peer reviewed
survival rate, we record the number of patients at risk at the
longest follow-up results. Four of the implants with no published results are said to have market shares of between
start of the trial and at the time of the analysis.
5% and 20%. We could find no published
for the THR then this information
was included. After the If a number
was not quoted this is indicated with a question mark. Very large or important studies of slightly shorter duration have also been included.
results for any of
the acetabular sockets marketed independently. Many of the distributors or manufacturers, particularly those based in continental Europe, report clinical results which have not been published in peer-reviewed journals.
RESULTS We identified 19 implant distributors or manufacturers (Table II). Only one was unwilling to have the THR which it sells presented
in this study. The information
DISCUSSION The number of THR designs available to surgeons is rapidly increasing, but there are no published results for
implants sold by this company is freely available and these
details have therefore
undoubtedly be unsatisfactory and will result in consider able patient suffering and expense. The problem of choice
however, not be completely correct, since it was not con firmed by the manufacturer.
of the implants.
of the new
is difficult in the UK, with 62 THRs on the market, but it is
We identified62 differentTHRs (TableI). Many stems worse world-wide. One company, to take an example, and sockets were sold independently, to allow surgeons to use different combinations. We included all such stems, but seven sockets sold independently were excluded. One
markets only three designs of THR in the UK, but world wide it markets 49. There is a need for a thorough review of the factors which are involved in the implant market.
The THR with the longest follow-up is the Charnley implant was bipolar.The number of new implants intro duced to the UK marketeach year has increasedsteadily: design. It is widely considered to be the best standard for nine (15%) were introducedin 1993 and seven (11%) in comparison (Bulstrode 1987; Wroblewski and Siney 1993), 1992. Only four of those still on the market were intro duced before 1980, and about 50% were added in the last five years. Only the Charnley prosthesis was reported to have a market share of greater than 20%, and eight implants (8%) were said to have a share of between 5% and VOL. 77-B, No. 4, JULY 1995
with a published 20-year survival rate of between 85% and 90% (Schulte et al 1993; Neumann, Freund and SÃ˜renson 1994). Since its development in the 1960s there have been many innovations, both in implants and surgical tech
niques, but these do not appear to have improved the results
implant, and many patient-related factors. It is therefore important that surgeons should make the decision as to which implant should be used for each patient. This deci sion should be based primarily on sound clinical evidence.
The Charnleyis also one of the cheapestimplants,and it therefore seems surprising that so many others have been made available. There are reasons for this: the number of revisions
of the very
The surgeon must be certain (and be able to justify to
number of primary THRs; the results of revision arthroplas ties are substantially
and some primary
others) that the implant will provide clinical results at least as good as those for the currently available prostheses
have not been revised are unsatisfactory and cause patient suffering. Orthopaedic surgeons therefore see many prob lems and are keen to develop better implants. There is also considerable financial incentive for companies to modify implants or to introduce completely new designs every few years (Sarmiento 1991 ; Bulstrode et al 1993). This tenden cy is clearly shown by the fact that 50% of the available designs of implants years.
have been introduced
known to give the best long-termclinical outcome.Other factorsare of secondaryimportance.Implantsthat perform well in preclinical laboratory testing may not necessarily perform satisfactorily in the clinical situation. Cheap implants are often copies of more established implants, but with minor alterations, theoretically designed to improve
theirfunction.if thesealterationsproveto be unsatisfactory
in the last five
in the longer term, the small early saving for the purchaser will result in the large late cost of early revision surgery. It
The results of a THR depend on a number of factors, only one of which is the implant. Other, possibly more important factors, are the techniques used, the instrumenta tion, the skill of the surgeon, experience with that particular
is clear that many, apparently minor alterations, which on theoretical grounds should improve clinical outcome, such as stem shape, surface finish, precoating and metal backing,
Table manufacturersDistributor II. Details of 19 distributorsor (Manufacturer)AddressThlephone3M
HealthCare LtdLowton 611611Aesculap
Way,Morley Street,Loughborough, Leicestershire
Pro (UK) LtdHerriard 543099Biomet LtdWaterton 655221Corin
The Technopark, Newmarket Road, Cambridge CBS 8PB01223
Implants 0268STRATEC WorldwideBiomedical Medical Ltd20 332212Zimmer LtdDunbeath
Engineering Department, Royal National Orthopaedic Hospital,
Brockley Hill, Stanmore, Middlesex HAl 4LP0181 Tewin Road, Welwyn Garden City, Herts AL7 1LG01707 Road, Elgin Industrial Estate, Swindon, Wiltshire
THE JOURNAL OF BONE AND JOINT SURGERY
WHICH PRIMARY TOTAL HIP REPLACEMENT?
may in practice
make things worse not better (Fowler
1988; Wilson-MacDonald and Morscher 1990; Keating 1993; Gardiner and Hozack 1994). About 90% of implants are now modular, and although this offers some advantages, it is not without complications (Barrack et al 1993). The new modular implants will need to be monitored carefully, because clinical results from their monobloc forebears cannot be extrapolated to modular derivative designs. The relevant information on which to base the choice of THR should be available in an unbiased and readily assim ilable form. Table I is a step towards this, and should be
(Fowler et al 1988), but no long-term survival study has yet been published.
If this was done, it would
show very good results, because there were early failures for various technical reasons such as a change in surface finish and over-machining, which have now been identified and corrected (Fowler et al 1988; Malchau et al 1993). It has been suggested that some new implants are performing
beuer at five years than the Chamley THR (Malchau et al
used in conjunction with more detailed information from manufacturers (Table II) and from journals. We have not
1993). This evidence is weak; other factors, particularly surgeon-dependent ones, may be responsible for the good results (Malchau et al 1993). The only valid method of comparing implants and identifying other important vari ables, especially those which are surgeon- and technique related is to organise and perform randomised multicentre
attempted a mets-analysis because of the lack of available
The large number of implants on the market, most of which have no published results, is unsatisfactory and is almost certainly causing harm to patients. The simplest way to address this problem is for orthopaedic surgeons to select implants on the basis of good clinical results published in peer-reviewed journals (Goodfellow 1992). This would not only prevent many disasters, but would also encourage manufacturers to support clinical studies of their new implants. We do not believe that surgeons should be forced
ences were obtained mainly from the manufacturers as we believe that they should have this information readily available. Clinical results not published in peer-reviewed journals must be interpreted with extreme caution. For example, one manufacturer's advertising states that â€œthe unaltered stem design has been successfully
used in thousands
tions since 1985 with no report of aseptic looseningâ€•,when it is known to the orthopaedic community that there have been such revisions
1994). We plan to
maintain and expand our database and would welcome more information on the clinical results of implants which have been published in peer-reviewed journals anywhere in the world. There are problems with using clinical results as a basis
on which to choose an implant, the most important of which is that there are very few randomised trials which compare implants (Bradley 1994; Marston and Bentley 1994). Most implants are modified every few years and the results of long-term trials may therefore have little rele vance to the implants currently being used. There is even some evidence to suggest that the Charnley THR which is now available may not be as successful as earlier versions (Dalietal 1988).
It is probably fair to say that implants with ten-year
et al 1993).
to use only established implants; this might prevent the development of new implants that in the long term will have superior results. If clinical results are not already available,
a new implant
should only be used if it
is included in a properly conducted clinical trial. Such trials could use a standardised patient-based outcome measure in the form of a questionnaire. The dissemination of such data could be by publication in a standard format, possibly in a new journal. Ideally, a national register should be established. New techniques
are being developed
which can predict
of an implant within a few
years. These should be used more widely
for the develop
ment and testing of new implants. One possible method is to study the early migration of THR components in bone using
survival results as good as those for the Charnley design will be approximately as good in the long term. This may apply to some but not all implants with good five-year results: recently, an uncemented THR with a five-year
(Council Directive 93/42/EEC 1993), and after a transi tional period, some form of clinical investigation may become obligatory before a new implant can carry a CE mark. There is now an opportunity to rationalise the implant market.
to that for the Charnley
1993) was shown to have an eight-year survival which was much worse (Owen et al 1994). Survival analysis has a number of potential problems (Murray et al 1993), not all of which are circumvented by using large numbers as in the Swedish hip register (Mal chau et al 1993). Although comparisons between implants are most easily made with survival analysis, it is clear that some implants may be good even if they have not had a long-term survival analysis. For example the Exeter THR has reports of results after up to 16 years' follow-up VOL. 77-B, No. 4, JULY 1995
(SÃ¸balle et al 1993; Kiss et al 1994).
A directive on medical devices of the Council of the European Communities recommends that implant perform ance and side-effects
We believe that implants should be divided into three groups. Group A would be the small group with published long-term clinical results that would allow the patient, the purchaser,
and the surgeon
to be reasonably
the implant is safe and will give reliable and reproducible results. Group B would include implants with good short
D. W. MURRAY, A. J. CARR, C. J. BULSTRODE
term published results, but during the transitional period this group would also include implants already on the
market with no published results. Surgeons may choose to
Dali DM, Learmonth
IA, Myles A, Solomon A. A comparison of the first
and second generation Chamley femoral stem in total hip replacement. Pmcs 55th meeting American Academy 1988.
use group-B implants for various reasons, but it seems only reasonable that purchasers and patients should be aware
that there is a degree of uncertainty about their long-term
some form of clinical testing as well as laboratory wear testing before they are released to the general market. Modem prediction techniques would serve to weed out
those which are at a high risk of poor long-term results. Implants which performed satisfactorily in group C would be eligible to move into group B. The threshold to move from group B into group A could be set so that only implants with good long-term results would be eligible. A ten-year
implants in group A would seem to be a reasonable level. Failure rates which were significantly worse than this should not only debar the implant from entering group A, but also suggest that it should be withdrawn from the market. Condusions. The surgeon should decide which THR to use: the choice should be based on sound clinical grounds, bearing in mind how long the implant may have to function. The current
every few years,
without changing its name, should cease. MOdified implants should be regarded as new designs. Surgeons should use
implants with no published clinical data only when they are included in a properly conducted trial or register. The intro duction of the CE mark provides an important opportunity to rationalise the implant market in Europe. The authors would like to thank the implant disthbutors/manufacturers and Mrs Barbara Marks for their help with collecting the information, and
Biomet Ltd for financial support. No benefits in any form have been received or will be received from a
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