No bias for developer publications and no difference between first-generation trochlear-resurfacing versus trochlear-cutting implants in 15,306 cases of patellofemoral joint arthroplasty

PURPOSE AND HYPOTHESIS

The study aim was to assess the outcome of patellofemoral arthroplasty (PFA), paying particular interest to 'revisions for any reason'. The hypothesis was that there is a superior outcome of PFA reported in dependent clinical studies in contrast to independent clinical literature and that there is a superior outcome of 'trochlear-cutting' PFA in comparison with 'first-generation trochlear-resurfacing' implants.

METHODS

Studies on PFA from its market introduction in 1955 onwards were systematically reviewed. The revision rate, which was calculated as 'revisions per 100 component years (CY)', was evaluated in 45 studies published in indexed, peer-reviewed international scientific journals. In addition, 'first-generation trochlear-resurfacing' and 'trochlear-cutting' implants as well as dependent and independent clinical literature were analysed. Furthermore, the data of three arthroplasty registers were analysed.

RESULTS

A total of 15,306 PFA were included consisting of 2266 cases in worldwide literature data and of 13,040 cases in register data. 2.22 revisions per 100 CY were observed in worldwide literature data, which corresponds to a revision rate of 22.2% after 10 years. Revision rates between 18.9 and 27% after 10 years were shown by the included three national joint registers. In the group analyses no significant differences were detected.

CONCLUSIONS

This meta-analysis did not reveal significant differences in the comparison between developer over independent publications and between 'first-generation-resurfacing' over 'trochlear-cutting' implants. In conclusion the data of developer publications do not seem to be biased. 'Trochlear-cutting' devices of PFA had slightly superior outcomes, but that benefit was not statistically significant. Nevertheless, we would recommend 'trochlear-cutting' devices for further use in PFA.

LEVEL OF EVIDENCE

Meta-analysis of Level IV case series.

The incidence of implant fractures after knee arthroplasty

PURPOSE

This study aimed to evaluate the incidence of "implant" fractures after knee arthroplasty using clinical literature and worldwide arthroplasty registers. The hypothesis was that register datasets report higher rates of these rare complications than clinical studies.

METHODS

Calculations were based on the pooled incidence of revision operations after fractures of knee arthroplasties, comparing clinical studies published in MEDLINE-listed journals and annual reports from worldwide arthroplasty registers in a structured literature analysis based on a standardized methodology.

RESULTS

Twelve clinical studies and datasets from six worldwide registers were included. Rates of fractures of knee arthroplasties were reported from 0.2 to 2.5 % in clinical studies versus 0.02-0.17 % in worldwide arthroplasty registers.

CONCLUSIONS

Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. Unicompartmental knee arthroplasty (UKA) implanted before 2000, constrained primary or revision constrained total knee arthroplasties, and patellar replacements showed the highest incidence of implant fracture. The results of this analysis can help clinicians to counsel patients on potential complications following knee arthroplasty.

LEVEL OF EVIDENCE

III.

New regulations for medical devices: Rationale, advances and impact on research and patient care

A series of events relating to inferior medical devices has brought about changes in the legal requirements regarding quality control on the part of regulators. Apart from clinical studies, register and routine data will play an essential role in this context. To ensure adequate use of these data, adapted methodologies are required as register data in fact represent a new scientific entity. For the interpretation of register and routine data several limitations of published data should be taken into account. In many cases essential parameters of study cohorts - such as age, comorbidities, the patients’ risk profiles or the hospital profile - are not presented. Required data and evaluation procedures differ significantly, for example, between hip and spine implants. A “one fits for all” methodology is quite unlikely to exist and vigorous efforts will be required to develop suitable standards in the next future. The new legislation will affect all high-risk products, besides joint implants also contact lenses, cardiac pacemakers or stents, for example, the new regulations can markedly enhance product quality monitoring. Register data and clinical studies should not be considered as competitors, they complement each other when used responsibly. In the future follow-up studies should increasingly focus on specific questions, while global follow-up investigations regarding product complication rates and surgical methods will increasingly be covered by registers.

Quality of outcome data in knee arthroplasty

BACKGROUND AND PURPOSE

Recent reports on developer bias in unicondylar knee arthroplasty led to concerns about quality of publications regarding knee implants. We therefore compared revision rates of registry and non-registry studies from the beginning of knee arthroplasty up to the present. We assessed the time interval between market introduction of an implant and emergence of reliable data in non-registry studies.

MATERIAL AND METHODS

We systematically reviewed registry studies (n = 6) and non-registry studies (n = 241) on knee arthroplasty published in indexed, peer-reviewed international scientific journals. The main outcome measure was revision rate per 100 observed component years.

RESULTS AND INTERPRETATION

For 82% of the 34 knee implants assessed, revision data from non-registry studies are either absent or poor. 91% of all studies were published in the second and third decade after market introduction. Only 5% of all studies and 1% of all revisions were published in the first decade. The first publications on revision rates of total knee arthroplasty (TKA) started 6 years after market introduction, and reliable data were found from year 12 onward in non-registry studies. However, in unicondylar knee arthroplasty (UKA) the first publications on revision rates could be found first 13 years after market introduction. Revision rates of TKA from non-registry studies were reliable after year 12 following market introduction. UKA revision rates remained below the threshold of registry indices, and failed to demonstrate adjustment towards registries. Thus, the superiority of registry data over non-registry data regarding outcome measurement was validated.

The incidence of implant fractures after total hip arthroplasty

PURPOSE

Implant fractures after total hip arthroplasty (THA) are considered as rare in clinical practice. Nevertheless they are relevant complications for patients, physicians, and the public health system leading to high socioeconomic burdens. The aim of this study was to assess the incidence of fractures after THAs in a comparative analysis of clinical studies and worldwide arthroplasty register datasets.

METHODS

We calculated the pooled incidence of revision operations after fractures of THAs in a comparison of clinical studies published in Medline-listed journals and annual reports of worldwide arthroplasty registers in a structured literature analysis based on a standardised methodology.

RESULTS

Included clinical studies (sample-based datasets) were mono-centre trials comprising a cumulative number of approximately 70,000 primary implantations whereas worldwide national arthroplasty register datasets referred to 733,000 primary implantations, i.e. approximately ten times as many as sample-based datasets. In general, sample-based datasets presented higher revision rates than register datasets with a maximum deviation of a 14.5 ratio for ceramic heads, respectively. The incidence of implant fractures in total hip arthroplasty in pooled worldwide arthroplasty register datasets is 304 fractures per 100,000 implants. In other words, one out of 323 patients has to undergo revision surgery due to an implant fracture after THA in their lifetime.

CONCLUSIONS

Implant fractures in total hip arthroplasty occur in a relevant number of patients. The authors believe that comprehensive arthroplasty register datasets allow more general evaluations and conclusions on that topic in contrast to clinical studies.

Revision surgery after total joint arthroplasty: a complication-based analysis using worldwide arthroplasty registers

The authors performed a complication-based analysis of total knee (TKA), total hip (THA), and total ankle arthroplasty (TAA) using worldwide arthroplasty registers. We extracted data with respect to reason for revision surgery and pooled causes. The most common causes for revisions in THA were aseptic loosening (55.2%), dislocation (11.8 %), septic loosening (7.5%), periprosthetic fractures (6%), and others. The most common causes in TKA were aseptic loosening (29.8%), septic loosening (14.8%), pain (9.5%), wear (8.2%), and others. The most common causes in TAA were aseptic loosening (38%), technical errors (15%), pain (12%), septic loosening (9.8%), and others. Revisions in TKA and THA differ with respect to type of complication. However, in case of TAA, higher rates of technically related complications are reported.

Comparative pooled survival and revision rate of Austin-Moore hip arthroplasty in published literature and arthroplasty register data

The aim was to evaluate the pooled survival and revision rate of Austin-Moore hip arthroplasty (AMHA) in published literature and arthroplasty register data. A comprehensive literature analysis of clinical publications and register reports was conducted with the main endpoints revision surgery and revision rate. Sixteen relevant clinical studies have been found to significantly underestimate revision rates by a ratio of 2.15 compared to register data sets. The medium-term outcome of AMHA showed significantly worse outcomes than the use of other bipolar implants, or modular cervicocephalic prostheses and data of journal publications on revision rates deviate significantly from data of arthroplasty registers.

Application and surgical technique of total knee arthroplasties: a systematic comparative analysis using worldwide registers

PURPOSE

The aim of this study was to compare total knee arthroplasty (TKA) procedures between different countries with regard to epidemiological data and surgical technique by reference to the worldwide arthroplasty registers.

METHODS

A systematic search was carried out using the EFORT website to identify the relevant arthroplasty registers. We extracted data with respect to the number of implanted TKAs, patients' age distribution, procedure types, and revision rates. After identification of 28 national arthroplasty registers, 11 offered sufficient data regarding the above mentioned parameters and were therefore included in the final analysis.

RESULTS

A large variation was found in the annual number of primary TKA implantations per inhabitant with a reported range from 30 to 199 per 100,000 (mean 106). The fixation method varied strongly between the different registers as well, e.g. 90 % of totally cemented TKAs in Sweden, England and Wales, Slovakia, and New Zealand versus 54 % cemented fixation in Australia. Another significant difference between included countries was observed with respect to the use of patellar resurfacing in TKA. Whilst the Danish knee arthroplasty register reports a percentage of 72 % using a patellar button in TKA the register from Norway reports only a minority of 2 %.

CONCLUSIONS

The comparison of arthroplasty registers revealed large differences regarding the annual number of primary TKAs per inhabitant and primary TKA procedure types. These variations may be explained by several factors such as patient demographics (prevalence of osteoarthritis) and national conditions such as healthcare systems (insurance status), number or availability of performing surgeons, medical facilities and surgeon-dependent factors such as definition of indications, education, tradition and experience.

[Revision rates in journal publications on joint prostheses with noticeably high failure rates in register data sets]

BACKGROUND AND AIM OF STUDY

The value of outcome quality data from clinical studies is an issue of controversial debate particularly in the context of adverse events. The aim of this study is to present and evaluate the data available from clinical studies for products that show inferior outcome in registers and to assess the possibility to draw valid conclusions from these data. STUDY DESIGN AND ANALYTICAL METHODS: Based on a structured literature research, a comparative analysis was made of the revision rates of 12 products showing significantly inferior average results in registers. The primary outcome parameter was the revision rate for any reason calculated using a standardized methodology and the parameter of revisions per 100 observed component years.

RESULTS

For 5 out of 12 products not a single comparable study was available and relatively few data were available for the remaining products. A conventional meta-analysis revealed that only three products showed results that were comparable with those from registers. For 75% of products good results were published. There was not a single case where it would have been possible to identify or isolate the problems that had led to the underperformance observed on the basis of clinical studies alone.

DISCUSSION

Clinical sample-based studies are not a suitable and reliable means to recognize potential product or handling problems and avoid risks for patients and physicians. In this respect registers can provide an essential contribution.

Pooled outcome of total hip arthroplasty with the CementLess Spotorno (CLS) system: a comparative analysis of clinical studies and worldwide arthroplasty register data

PURPOSE

Our aim was to elucidate the pooled outcome of the CementLess Spotorno (CLS) system in total hip arthroplasty (THA).

METHODS

We compared the outcome of clinical inventor studies, independent clinical studies, and worldwide register data. The main endpoints for analysis were revision rates.

RESULTS

Twenty clinical studies were evaluated and, with one exception, overall found revision rates largely in line with register data. Revision rates (revisions per 100 observed component years) range from 0.15 (inventor study) to 0.28 (independent studies) and 0.43 (register datasets).

CONCLUSION

Data of journal publications and register datasets using the CLS system do not differ significantly with respect to revision rates. Only the initial inventor study reports a revision rate three times lower than in pooled worldwide register datasets.

Revision rates after knee replacement. Cumulative results from worldwide clinical studies versus joint registers

OBJECTIVE

To assess revision rates after knee arthroplasty by comparing the cumulative results from worldwide clinical studies and arthroplasty registers. We hypothesised that the revision rate of all clinical studies of a given implant and register data would not differ significantly.

METHODS

A systematic review of clinical studies in indexed peer-reviewed journals was performed followed by internal and external validation. Parameters for measurement of revision were applied (Revision for any reason, Revisions per 100 observed component years). Register data served as control group.

RESULTS

Thirty-six knee arthroplasty systems were identified to meet the inclusion criteria: 21 total knee arthroplasty (TKA) systems, 14 unicondylar knee arthroplasty (UKA) systems, one patello-femoral implant system. For 13 systems (36%), no published study was available that contained revision data. For 17 implants (47%), publications were available dealing with radiographic, surgical or technical details, but power was too weak to compare revision rates at a significant level. Six implant systems (17%) had a significant number of revisions published and were finally analysed. In general, developers report better results than independent users. Studies from developers represent an overproportional share of all observed component years. Register data report overall 10-year revision rates of TKA of 6.2% (range: 4.9-7.8%), rates for UKA are 16.5% (range: 9.7-19.6%).

CONCLUSION

Revision rates of all clinical studies of a given implant do not differ significantly from register data. However, significant differences were found between the revision rates published by developers and register data. Therefore the different data need to be interpreted in the context of the source of the information.

Impact of implant developers on published outcome and reproducibility of cohort-based clinical studies in arthroplasty

BACKGROUND

The reproducibility of the results of cohort-based clinical studies of arthroplasty procedures by the average orthopaedic surgeon is a major issue involving the quality of the scientific literature. We compared the results of a comprehensive literature analysis with data from national arthroplasty registries to examine the influence of arthroplasty implant inventors on the outcomes published in peer-reviewed journals.

METHODS

A structured review of the literature published in MEDLINE-listed journals was performed. A comparison of the average revision rates in the identified studies (adjusted for the number of arthroplasty cases and the duration of follow-up) with the registry data was then conducted.

RESULTS

Seventeen of the analyzed arthroplasty implants were developed in the United States. Studies by the developers of these implants often had a substantial influence on the published outcome. For approximately 50% of the implant systems analyzed, the average revision rate derived by combining all published studies showed a statistically significant and clinically relevant deviation from the revision rate derived from the arthroplasty registry data, which reflected the outcome in the average patient. For the majority of implants for which the revision rate calculated from the published clinical studies was very low compared with the rate calculated from the registry data, the developing institution accounted for 39% to 100% of the published outcome data for the implant. In contrast, the published results were usually reproducible in clinical practice if <25% of the published data were reported by the developers. Three of the nine arthroplasty implants developed in Europe showed a significant and clinically relevant difference between the revision rate derived from only the studies published by the developers and the rate calculated from the registry data. However, because of the considerably greater amount of data from independent studies that was typically available for the European implants than for the American implants, studies by the developer that deviated significantly from the registry data could usually also be identified as outliers by a meta-analysis of all published studies. A high proportion of the published data involving three of the European implants was reported by the inventors, but comparison with the registry data revealed that the average published revision rates for two of these three implants were reproducible in clinical practice.

CONCLUSIONS

The published results of the clinical studies involving many of the arthroplasty implants, especially implants developed in the United States, were highly influenced by reports from the center that developed the implant. This often had a substantial effect on the reproducibility of the outcome data. There appeared to be relevant differences between the medical research systems in Europe and the United States that also affected the reproducibility and applicability of the results for the average surgeon. Registry data can contribute substantial added value to an informed discussion of arthroplasty outcomes.

Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries

BACKGROUND

The aim of this study was to evaluate the outcome of specific implants in total ankle arthroplasty as reported in clinical studies and determined by national registries.

MATERIALS AND METHODS

A structured literature review was conducted regarding sample-based clinical studies and national registry data. To allow for comparative analyses, registry data had to be available for the implants included. These were STAR Ankle, Büchel-Pappas, Hintegra, Mobility, Agility, and Ramses Total Ankle Arthroplasty. The revision rate was used as the main outcome parameter.

RESULTS

On average, the revision rates published in sample-based clinical studies were about half the value found in registries. Implant developers represent a share of almost 50% of the published content and are therefore over-represented in scientific publications. The inventors of STAR Ankle and BP total ankle implants published data which was statistically significantly superior to the outcome achieved in average patients as documented in registries. Irrespective of the implant, the average revision rate to be expected according to the registry data available is 21.8% after 5 years, and 43.5% after 10 years.

CONCLUSION

The average revision rate published in peer-reviewed scientific articles was significantly lower than the outcome achieved according to national arthroplasty registry data, which reflect actual average patient care in the respective countries. Publications by some research groups, particularly by implant inventors, show a deviation from the outcome published by other users and those shown in registry data.

Revision rates after total joint replacement: cumulative results from worldwide joint register datasets

In a systematic review, reports from national registers and clinical studies were identified and analysed with respect to revision rates after joint replacement, which were calculated as revisions per 100 observed component years. After primary hip replacement, a mean of 1.29 revisions per 100 observed component years was seen. The results after primary total knee replacement are 1.26 revisions per 100 observed component years, and 1.53 after medial unicompartmental replacement. After total ankle replacement a mean of 3.29 revisions per 100 observed component years was seen. The outcomes of total hip and knee replacement are almost identical. Revision rates of about 6% after five years and 12% after ten years are to be expected.

Outcome of the cementless Taperloc stem: a comprehensive literature review including arthroplasty register data

BACKGROUND AND PURPOSE

The validity of various data sources for the assessment of the outcome quality of medical devices was investigated by comparative analysis of the published data sources available for a sample of implants. It was the aim of the study to determine the performance of this implant and to identify potential bias factors inherent to the various datasets.

METHODS

A comprehensive literature search was carried out from English-language, peer-reviewed journals and worldwide reports from national arthroplasty registers. Publications from Medline-listed journals were included. The main parameter was revision rate, calculated as "revisions per 100 observed component years" to allow adjusted direct comparison of different datasets.

RESULTS

Of 16 clinical studies that met the inclusion criteria, 9 originated from the implant developer's hospital. In the clinical studies category, publications from the developer's hospital suggested considerably lower revision rates than the other datasets. In fact, the values quoted were 5.5 times below the average of all other studies, and 9.51 times lower than in the Australian arthroplasty register. These differences are statistically significant.

INTERPRETATION

The cementless Taperloc stem is an implant that shows good performance regarding revision rates in registry data and in clinical studies. However, the excellent results published by the developer's clinic are generally not reproducible by other surgeons. In terms of reference data, registry data are able to make an important contribution to the assessment of clinical sample-based studies, particularly regarding evaluation of the extent to which published results are reproducible in daily routine.

Outcome and reproducibility of data concerning the Oxford unicompartmental knee arthroplasty: a structured literature review including arthroplasty registry data

BACKGROUND AND PURPOSE

The reproducibility of results and potential confounders in sample-based studies is important to consider in the assessment of studies. Comprehensive arthroplasty registers could serve as a reference dataset for comparative analyses. We analyzed an implant that is frequently used worldwide, the Oxford unicompartmental knee replacement, in order to identify potential confounders inherent in the datasets and to evaluate the outcome achieved with this implant.

METHODS

We performed a structured literature review of the data published on the revision rate of the Oxford medial unicompartmental arthroplasty. Both clinical follow-up studies and worldwide registry data were included. Confidence intervals were calculated to determine the statistical significance of differences.

RESULTS

A substantial proportion of the published data (52-68% depending on the method of calculation) is derived from studies involving participation of the institution that developed the implant. The results published by this group show a statistically significant deviation from the reference datasets from registers or independent studies. Data from the developing hospital show mean revision rates that are 4 times lower than those based on worldwide register data, and 3 times lower than the ones quoted in independent studies. On average, the data published in independent studies are reproducible in registry data.

INTERPRETATION

A conventional meta-analysis of clinical studies is substantially affected by the influence of the developing hospital, and is therefore subject to bias. For assessment of the outcome of implants, registry data are superior and, in terms of reference data for the detection of potential bias factors in the literature, could make an essential contribution to meta-analyses.

[Detection of inferior products in arthroplasty and implementation of findings: a retrospective analysis of the Boneloc incident]

AIM

By a retrospective assessment of the Boneloc incident, a bone cement which had an inferior outcome in terms of survival rate, the value of published datasets for the detection of inferior outcomes was evaluated.

METHOD

A structured literature review of English and German peer reviewed journals was conducted. The articles were assessed with respect to revision rate and statements about the product. In a standardised methodology, adjusted for number of cases and follow-up period, the revision rate was calculated. Main goal was to assess the agreement of published information from different datasets.

RESULTS

In the first 4 years after Boneloc had been brought on the market exclusively experimental studies were published, most of which were in favour of the product. In 1995, clinical studies, migration analyses and register-based articles were published. Most of them reported about inferior results, in the same year Boneloc was taken from the market worldwide. Sample-based clinical follow-up studies were not able to contribute to the decision-making process, they were published with a delay of several years and were underpowered from a statistical point of view. All of them published critical statements--after the product had no longer been available on the market for many years. The average revision rate in sample-based studies exceeded the reference value in the Norwegian Arthroplasty Register 7.35-fold. When the inferior results with Boneloc were published, the product had already disappeared from the national markets in Scandinavian countries' operating registers. The central position of orthopaedic scientific societies in the entire outcome monitoring system in these countries seems to be a key factor for success and rapid reaction to identified problems.

CONCLUSION

Arthroplasty registers and migration analyses have the highest value for the rapid and reliable detection of inferior outcomes in comparative analyses of published articles. Experimental studies did not agree with the performance of the product in a retrospective view, the data cannot be transferred from the estimation of future clinical outcome like survival rates. The involvement of scientific societies in the assessment and dissemination of the results is a key factor to realise potential benefit by an advanced quality monitoring project like arthroplasty registers.

High failure rate of the Duraloc Constrained Inlay

BACKGROUND AND PURPOSE

After total hip arthroplasty, dislocations are a frequent complication and are difficult to treat in some patients. A great variety of implants and antiluxation mechanisms are used in surgical therapy.

METHODS

8 patients had 9 Duraloc Constrained Inlays implanted at our clinic between October 2003 and November 2006, for recurrent dislocations. A retrospective follow-up study was carried out.

RESULTS

All patients suffered a failure of the expanding ring, the metal ring being squeezed out of the polyethylene notch. The mechanism of failure can be explained by impingement due to the implant design. At the time of writing, 3 patients have had to undergo revision surgery.

INTERPRETATION

The Duraloc Constrained Inlay has shown unacceptably high failure rates.

[The European Arthroplasty Register (EAR), development and rationale for supranational cooperation of arthroplasty registers]

In Scandinavia national arthroplasty registers are accepted instruments in the assessment of joint implants. They have contributed essentially to the rapid detection of inferior products and, by encouraging a continuous process of quality improvement through feedback, have helped to avoid revision operations. However, national registers have a limited significance with regard to other countries and rarely used implants. In recent years, a great number of registers have been founded. The European Arthroplasty Register (EAR), an EFORT project, aims at supporting these projects, enhancing cooperation within a network, realising further benefit through registers, and fostering scientific activities. The registers have been conceived according to the successful Scandinavian model. It is, however, necessary to adapt the concept to the individual national circumstances. In order to increase the value of register publications for other countries, it makes sense to achieve a minimum of stardardisation in datasets, definitions, product designations, as well as in evaluation and publication methods. Since the datasets of national registers implicitly reflect the prevailing national circumstances, they are always more valuable for use in the respective country than evaluations from aggregated, supranational and therefore larger datasets. Supranational evaluations may yield additional findings, but they cannot replace a national register. Therefore, EAR has been conceived as a network of independent national registers considering itself as a supplement and by no means as a competitor of the established national registers.

Key factors for a successful National Arthroplasty Register

Since the introduction of the first National Arthroplasty Register in Sweden in 1975, many other countries have tried to adopt the successful Scandinavian system. However, not all have overcome the political and practical difficulties of establishing a working register. We have surveyed the current registries to establish the key factors required for an effective database. We have received detailed information from 15 arthroplasty registers worldwide. The legal conditions under which they operate together with the methods of collection and handling of the data differ widely, but the fulfilment of certain criteria is necessary achieve a high degree of completeness of the data to ensure the provision of statistically relevant information.

Comparison of the information in arthroplasty registers from different countries

This article considers some of the problems of the interpretation of information from other national arthroplasty registers when setting up a new register. In order for the most useful information to be available from registers much international co-operation is required between all those responsible for the design of registers as well as those who gather, assess and publish the data.

[Influence of local anesthesia and energy level on the clinical outcome of extracorporeal shock wave-treatment of chronic plantar fasciitis]

BACKGROUND

The efficacy of low energy extracorporeal shock wave treatment (ESWT) for chronic plantar fasciitis is discussed controversially. It is unclear whether the simultaneous application of local anesthesia (LA) interferes with clinical outcome.

METHODS

60 patients with a chronic plantar fasciitis were enrolled in a triple-arm (20 patients per group), prospective randomized and observer-blinded pilot trial. The patients were randomly assigned to receive either active ESWT without LA (;3 x 1 500 shocks, total energy flux density [EFD] per shock 0.09 mJ/mm(2) [Group A]), ESWT with LA (3 x 1 500 shocks, EFD 0.18 mJ/mm(2) per shock [Group B]) or ESWT with LA (3 x 1 500 shocks, EFD 0.09 mJ/mm(2) [Group C]). Main outcome measures were: pain during first stepps in the morning (measured on a 0-10 point visual analogue scale) and number of patients with > 50 % reduction of pain and no further therapy needed, measured at 6 weeks after the last ESWT.

RESULTS

Group A improved in the VAS from 6.4 (SD: 1.7) to 2.2 (SD: 2.6) points, group B from 6.7 (SD: 1.5) to 4.1 (SD: 2.4) points, group C from 6.2 (SD: 1.6) to 3.8 (SD: 2.5) points. A reduction of pain of at least 50 % was achieved in 60 % of group A, in 36 % of group B and in 30 % of group C. Group A without LA showed a significantly higher improvement in the VAS and subjective evaluation than groups B (p = 0.007) and C (p = 0.016).

CONCLUSION

At 6 weeks success rates after low-energy ESWT with local anesthesia were significantly lower than after identical low-energy ESWT without local anesthesia. Higher energy levels could not balance the disadvantage of this effect. LA significantly influenced the clinical results after low energy ESWT in a negative way. Blinding patients by LA in ESWT studies must therefore be considered a systematic error in study design.

Radiologisches Erscheinungsbild des zementfreien ALLOCLASSIC SL-Schaftes bei sehr alten Patienten mit primärer Coxarthrose

AIM

The radiological appearance of the cementless ALLOCLASSIC SL-stem, implanted in patients with primary osteoarthritis of the hip and aged at least 80 years at time of surgery, was investigated.

METHOD

66 hips in 58 patients were analysed. 17 patients (19 hips) died in the interim, 5 patients (5 hips) were not available for follow-up because of health reasons (4) or lack of co-operation (1). 1 stem had to be explanted after a periprosthetic fracture of the femur. Finally, 41 total hip arthroplasties in 35 patients could be analysed after an average of 67.9 months (39.2-93.4).

RESULTS

Bone atrophy - especially in the proximal Gruen zones - was frequently found. In contrast, radiolucent lines and osteolyses were rare occurrences. The Harris Hip score was preoperatively on average 33.0 points, at time of follow-up 81.7 points. The survival rate (endpoint aseptic loosening) was 100 % after a mean follow-up of 5.7 years.

CONCLUSION

Also in very old patients the implantation of a cementless stem is possible and provides very good results.

Cementless total hip arthroplasty in patients older than 80 years of age

We reviewed 80 patients (87 hips) who were older than 80 years of age at the time of cementless total hip arthroplasty. An Alloclassic SL stem had been implanted in all patients. A variety of cementless acetabular components was used. After a mean follow-up of 69.3 months (39.2 to 94.1) 48 hips in 43 patients were analysed clinically and radiologically. One patient had sustained a traumatic periprosthetic fracture of the femur with subsequent exchange of the stem 73 months after operation. Thirty-two patients (34 hips) had died and five patients (five hips) were unavailable for follow-up because of health reasons (four patients) or lack of co-operation (one patient). If the endpoint is defined as removal of the prosthesis because of aseptic loosening, the survival rate was 100% for the cup and stem after 78 months. The mean Harris hip score was 81.9 points. Radiolucent lines and osteolysis were seldom found.

Cementless total hip arthroplasty in patients older than 80 years of age

We reviewed 80 patients (87 hips) who were older than 80 years of age at the time of cementless total hip arthroplasty. An Alloclassic SL stem had been implanted in all patients. A variety of cementless acetabular components was used. After a mean follow-up of 69.3 months (39.2 to 94.1) 48 hips in 43 patients were analysed clinically and radiologically. One patient had sustained a traumatic periprosthetic fracture of the femur with subsequent exchange of the stem 73 months after operation. Thirty-two patients (34 hips) had died and five patients (five hips) were unavailable for follow-up because of health reasons (four patients) or lack of co-operation (one patient). If the endpoint is defined as removal of the prosthesis because of aseptic loosening, the survival rate was 100% for the cup and stem after 78 months. The mean Harris hip score was 81.9 points. Radiolucent lines and osteolysis were seldom found.

[Minimally invasive medial unicompartmental knee replacement]

Medial unicompartmental knee replacements have been used for more than 40 years. Due to increased experience in determining the indication for use and improvements in design of the prosthesis and tribology, the long-term results have now reached a high level. The advantages of these systems are less bone loss and better proprioception. The disadvantage is the risk of panarthrosis, which might be reduced by accurate indications for operations. Good indications are patients older than 60 years with normal weight and normal sports activity. Well-functioning collateral and cruciate ligaments are mandatory. Due to the fact that during implantation eversion of the patella is not necessary, a minimally invasive approach might be used. Overcorrection of the mechanical axis of the leg should be avoided. By observing these principles, very good long-term results can be achieved with medial unicompartmental arthroplasty. Better proprioception and better mobility of the knee are advantages of these implants compared to total knee arthroplasty. In the case of revision with a bicondylar implant, the situation is less complex compared to revisions after osteotomies or bicondylar replacements. Remobilization in this situation is shorter with better results compared to a revision with a bicondylar prosthesis.

Side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of tennis elbow

Apart from a few observational reports, there are no studies on the side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of insertion tendopathies. Within the framework of a randomised, placebo-controlled, single-blind, multicentre study to test the effectiveness of ESWT in the case of lateral epicondylitis (LE), side-effects were systematically recorded. A total of 272 patients from 15 centres was allocated at random to active ESWT (3 x 2000 pulses, energy flux density ED(+) 0.04 to 0.22 mJ/mm(2) under local anaesthesia) or placebo ESWT. In all, 399 ESWT and 402 placebo treatments were analysed. More side-effects were documented in the ESWT group (OR = 4.3, CI = [2.9; 6.3]) than in the placebo group. Most frequently, transitory reddening of the skin (21.1%), pain (4.8%) and small haematomas (3.0%) were found. Migraine was registered in four and syncopes in three instances after ESWT. ESWT for LE with an energy flux density of ED(+) 0.04 to 0.22 mJ/mm(2) is a treatment method which has very few side-effects. The possibility of migraine being triggered by ESWT and the risk of a syncope should be taken into account in the future. No physical shock wave parameters could be definitely identified as the cause of the side-effects observed.

[Blood transfusion in total hip endoprosthesis operations in relation to Redon drainage and pressure bandages. An innovation in surgical method]

PROBLEM

There is a difference in the use of redon drainage following hip arthroplasty worldwide. The aim of the study was to find the best version.

METHOD

In a prospective randomized study including 158 patients with coxarthrosis we implanted cementless Alloclassic hip-endoprostheses and registered consumption of blood, blood loss, hemoglobin level, subcutaneuos hematoma, swelling of the proximal thigh, bleeding and exsudation of the wound in four groups supplied with three, two (subcutaneously and subfascial) and one (subcutaneously or subfascial) drainage with compression bandage and one group with two redons (subcutaneously and subfascial) without compression bandage. For prophylaxis of deep vein thrombosis we used low dose heparin.

RESULT

We could demonstrate, that the application of two redons one subcutaneously and one subfascial gave the best result. Compared to the conventional procedure with three redons we achieved a reduction of 47% of blood units, a significant reduction of exsudation and bleeding out of the wound, subcutaneous hematomas and a reduced swelling of the proximal leg in addition to better clinical conditions of the patients. The reason is a more accelerated stop of the bleeding out of the spongy bone. The application of one drain subcutaneously or subfascial showed no further reduction of blood loss, but an increase of wound exsudation and bleeding out the wound and an increase of subcutaneous hematomas. Sufficient external compression of the area of operation by a compression bandage is very important. Disadvantages as a result of changing the way of drainage have not been detected.

CONCLUSION

The use of two Redons one subcutaneously and one subfascial showed an obvious benefit without any clinical disadvantage compared to 3 redons or no drainage.