SurgeryEndo-GEPNCT07799818
Evaluation of Arthroplasty Treatment
An observational study of Surgery and Knee Arthropathy, run by University Hospital, Bonn at 1 site in Germany.
Trial summary
The aim of the study is to examine patients after knee and hip endoprosthesis in the longitudinal section and to evaluate the surgical outcome. Read more about this study
- Who is it for?
- Ages 18 to 100 years
- Conditions the study is for
- Surgery, Knee Arthropathy, Hip Arthropathy
- What is being tested?
- Joint replacement
- Type of treatment
- Surgery or procedure
- How many people
- 300 participants
- Where
- 1 siteGermany
- Study dates
- 1 Jul 2024to Aug 2029
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 100 years
- All sexes
- Adult, Older adult
Study population: In this longitudinal study, subjects will be recruited from the patient population of the orthopaedic outpatient clinic of the Clinic and Polyclinic for Orthopaedics and Trauma Surgery at the University Hospital Bonn. A total of 300 patients will be included. This explorative study design is based on the number of cases and the number of operations performed in recent years at the University Hospital Bonn, which amounts to approx. 550 arthroplasty operations per year.
Who may be able to join
- There is an indication for primary knee or hip replacement or revision.
- The subject is over 18 years of age.
- Written consent is given if the subject is fully responsible.
Who cannot join
- A known pregnancy
- A known mental or pain-associated illness
- Illness of an airborne infectious disease with an increased risk of mortality and morbidity
- Patient intolerances or restrictions that make participation in the study impossible
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Germany1 site, 1 recruiting
- Recruiting
Universitätsklinikum Bonn
Bonn, North Rhine-Westphalia, 53127
Andreas C Strauss, Prof., 022828714176, andreas.strauss@ukbonn.de
About this study
Official title: Evaluation in the Perioperative Course of Arthroplasty Treatment
The aim of the study is to examine patients after knee and hip endoprosthesis in the longitudinal section and to evaluate the surgical outcome.
Read the detailed description
In 2022, around 255,000 total hip arthroplasties and around 200,000 total knee arthroplasties were implanted in Germany and treated on an inpatient basis.
However, studies show that 15-30% of patients are not satisfied with the postoperative outcome of total knee arthroplasty. Various factors, such as preoperative pain and mental and physical health, are important for subjective satisfaction. For the objective functional results, other factors such as the indication, age and lifestyle are added, which can influence the postoperative result.
These figures initially relate to primary joint replacement. However, it is not uncommon for a repeat procedure, known as a revision, to be indicated postoperatively. In Germany, for example, 12.6% of knee endoprostheses required revision in 2018. Studies have shown that the most common reasons for hip revision are aseptic loosening in 23% of cases, functional instability in 22% and periprosthetic infection (PPI) in 22%. With an incidence of 1-2% and increasing case numbers, PPI is a relevant problem in arthroplasty treatment. In the postoperative course, a bacterial infection of the prosthesis-bearing bone, the joint and/or the surrounding tissue occurs. If symptoms persist or the prosthesis is unstable, a one-stage or two-stage prosthesis replacement with subsequent antibiotic therapy is performed. When choosing the treatment, the focus should be on improving quality of life, which includes reducing pain, maintaining function and, last but not least, reducing infection-related morbidity and mortality.
In order to be able to comprehensively track the course of treatment of joint surgery patients (preoperative condition, surgery performed, subsequent hospitalization, postoperative outcome, any subsequent complications and further interventions), structural and temporally consistent documentation and examinations of patients are required.
The aim of the study is to correlate the multiple parameters that influence the course of treatment and the surgical outcome and thus obtain a holistic picture of the patient in order to improve joint surgery care.
Primary questions:
- How does the physical and mental health status of patients change after joint surgery?
- How does the body composition change after joint revision?
- How does the perceived pain change perioperatively?
Secondary questions:
- What is the impact of joint surgery and hospitalised stay on functional characteristics such as muscular status of patients?
- What influence does the chosen procedure (one-stage vs. two-stage/long vs. short interval) in revision arthroplasty have on the course of treatment?
- How does the global and local bone density adapt after the use of metaphyseal components in knee joint replacement?
- Utilisation of osteoarthritic cartilage cells for testing novel therapeutic methods to stimulate cartilage regenerative processes.
- Do osteoarthritic cartilage cells from different donors differ in their functional phenotype?
- What role does the immune system play in the pre-, peri- and postoperative course of joint surgery?
- How can joint infection be better diagnosed and treated?
- Conditions
- Surgery, Knee Arthropathy, Hip Arthropathy, Prosthetic-joint Infection
- Being tested
- Joint replacement
- Keywords
- Joint prostheses, Joint surgery, Knee, Hip
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Joint replacementProcedure or surgery
Also called Endoprothetics, Arthroplasty
Patients routinely receive a joint replacement.
| Study group | Role | What they receive |
|---|---|---|
| Primary knee prosthesis | Patients who receive a primary knee prosthesis. Receives: Procedure: Joint replacement | |
| Primary hip prosthesis | Patients who receive a primary hip prosthesis. Receives: Procedure: Joint replacement | |
| Revision knee prosthesis | Patients who receive a revision of the knee prosthesis. Receives: Procedure: Joint replacement | |
| Revision hip prosthesis | Patients who receive a revision of the hip prosthesis. Receives: Procedure: Joint replacement |
What is being measured
The primary outcome is the main question the study is designed to answer.
SF 12 Questionnaire
Health-related quality of life assessed by the SF-12 (score for physical components (PCS) and total score for mental components (MCS) - higher values mean better health, lower values mean worse health with a statistical mean of the total score of 50 (SD 10) (1-100)
Measured: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Hand-held dynamometer
Hand grip force using a hand dynamometer in absolute values (in kg).
Measured: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Dual-Energy X-Ray Absorptiometry
Bone density values by DXA measurement (T- or Z-values as deviation of the measured value from predefined mean values. T-Score ≤ -1 = osteopenia; T-Score ≤ -2,5 = osteoporosis.
Measured: preoperative (approx. 1Day)
Dual-Energy X-Ray Absorptiometry
Body composition in relation to the lean mass. Fat Mass and Lean mass (gram).
Measured: preoperative (approx. 1Day)
Dual-Energy X-Ray Absorptiometry
Fat Mass in percent.
Measured: preoperative (approx. 1Day)
Secondary outcomes (5)
Joint examination (HJHS)
The hemophilia joint health score is a combined test of questioning and clinical examination with a goniometer and examines both elbow, knee and ankle joints using a goniometer for range of motion and axial alignment (0-3 points), pain numerical rating scale (0-10 points), swelling (0-3 points), crepitation (0-2 points) and gait abnormalities (0-4 points). A "total score" of 0 to 124 points is achievable. A higher score means a worse joint status.
Measured: preoperative (approx. 1Day)
Hip examination (Harris Hip Score)
The Harris Hip Score is is a combined test of questioning and clinical examination with a goniometer to assess hip complaints. The perceived pain, the function of the joint, existing deformities and the range of motion are assessed or queried with a total score of 0-100 points, with a low score indicating a functionally poorer hip joint.
Measured: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Knee examination (Knee Society Score)
The Knee Society Score is a combined test of questioning and clinical examination with a goniometer and evaluates the functional ability of the knee joint after total or partial knee arthroplasty. This includes objective (knee alignment, knee instability, range of motion), functional (standard and advanced activities) and subjective (patient expectations and satisfaction, symptoms) components. A total of 0-100 points can be achieved, with a lower value signaling a poorer assessment of the knee joint.
Measured: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Blood samples
The blood samples of all patients are collected in the clinical routine in preparation for surgery and during the inpatient stay. As part of the study, the parameters vitamin D3 (nmol/l), calcium (nmol/l), creatine kinase (U/l), TSH (µu/ml), C-reactive protein (mg/l), leukocytes (G/l), hemoglobin (%) are used for statistical analyses.
Measured: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Biomaterial
Biomaterial that is obtained/discarded as standard during the surgical procedure (Bone, cartilage, synovial fluid, synovial mucosa, Hoffa fat bodies). After preparation, the samples are stored at -80°C or -150°C until the measurements. Once the sample collection is complete, the stored samples are further processed for the measurements according to the manufacturer's instructions in order to determine and quantify inflammatory mediators or cell populations from the blood and tissue samples using an immunoassay (e.g. ELISA, multiplex approach, flow cytometry, proteomics, RNAseq, in vitro functional assay). The inflammatory mediators/cell populations are then analysed pseudonymously on the basis of the clinical course and in the context of the microbiological, histological, laboratory chemical and imaging findings from the patient file, which were routinely collected during the inpatient stay.
Measured: during operation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Sep 2026
- Study start1 Jul 2024
- Primary completionJun 2029 (estimated)
- Study completionAug 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for SurgeryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Bonn
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, PD Dr. Andreas Strauß, University Hospital, Bonn
- Investigators
- Andreas C. Strauss, PD Dr. med., Principal investigator, University Hospital, Bonn
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07799818
- Sponsor's protocol ID
- EndoGEP2024
- Acronym
- Endo-GEP
- Status last verified
- Aug 2026
- First submitted
- 18 Apr 2024
- Last updated
- 2 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The publication of anonymous patient data is not allowed by informed consent.
Study at a glance
From the registry record, last updated by the sponsor on 2 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation in the Perioperative Course of Arthroplasty Treatment
- ClinicalTrials.gov ID
- NCT07799818
- Acronym / sponsor ID
- Endo-GEP / EndoGEP2024
- Conditions
- Surgery, Knee Arthropathy, Hip Arthropathy, Prosthetic-joint Infection
- Keywords
- Joint prostheses, Joint surgery, Knee, Hip
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 300 participants (estimated)
- Lead sponsor
- University Hospital, BonnUniversity, hospital or other
- Study start
- 1 Jul 2024 (actual)
- Primary completion
- Jun 2029 (estimated)
- Study completion
- Aug 2029 (estimated)
- First posted
- 2 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The aim of the study is to examine patients after knee and hip endoprosthesis in the longitudinal section and to evaluate the surgical outcome.
Detailed description
In 2022, around 255,000 total hip arthroplasties and around 200,000 total knee arthroplasties were implanted in Germany and treated on an inpatient basis.
However, studies show that 15-30% of patients are not satisfied with the postoperative outcome of total knee arthroplasty. Various factors, such as preoperative pain and mental and physical health, are important for subjective satisfaction. For the objective functional results, other factors such as the indication, age and lifestyle are added, which can influence the postoperative result.
These figures initially relate to primary joint replacement. However, it is not uncommon for a repeat procedure, known as a revision, to be indicated postoperatively. In Germany, for example, 12.6% of knee endoprostheses required revision in 2018. Studies have shown that the most common reasons for hip revision are aseptic loosening in 23% of cases, functional instability in 22% and periprosthetic infection (PPI) in 22%. With an incidence of 1-2% and increasing case numbers, PPI is a relevant problem in arthroplasty treatment. In the postoperative course, a bacterial infection of the prosthesis-bearing bone, the joint and/or the surrounding tissue occurs. If symptoms persist or the prosthesis is unstable, a one-stage or two-stage prosthesis replacement with subsequent antibiotic therapy is performed. When choosing the treatment, the focus should be on improving quality of life, which includes reducing pain, maintaining function and, last but not least, reducing infection-related morbidity and mortality.
In order to be able to comprehensively track the course of treatment of joint surgery patients (preoperative condition, surgery performed, subsequent hospitalization, postoperative outcome, any subsequent complications and further interventions), structural and temporally consistent documentation and examinations of patients are required.
The aim of the study is to correlate the multiple parameters that influence the course of treatment and the surgical outcome and thus obtain a holistic picture of the patient in order to improve joint surgery care.
Primary questions:
- How does the physical and mental health status of patients change after joint surgery?
- How does the body composition change after joint revision?
- How does the perceived pain change perioperatively?
Secondary questions:
- What is the impact of joint surgery and hospitalised stay on functional characteristics such as muscular status of patients?
- What influence does the chosen procedure (one-stage vs. two-stage/long vs. short interval) in revision arthroplasty have on the course of treatment?
- How does the global and local bone density adapt after the use of metaphyseal components in knee joint replacement?
- Utilisation of osteoarthritic cartilage cells for testing novel therapeutic methods to stimulate cartilage regenerative processes.
- Do osteoarthritic cartilage cells from different donors differ in their functional phenotype?
- What role does the immune system play in the pre-, peri- and postoperative course of joint surgery?
- How can joint infection be better diagnosed and treated?
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Primary knee prosthesis | – | Procedure: Joint replacementPatients who receive a primary knee prosthesis. |
| Primary hip prosthesis | – | Procedure: Joint replacementPatients who receive a primary hip prosthesis. |
| Revision knee prosthesis | – | Procedure: Joint replacementPatients who receive a revision of the knee prosthesis. |
| Revision hip prosthesis | – | Procedure: Joint replacementPatients who receive a revision of the hip prosthesis. |
Who may qualify
- Ages
- 18 to 100 years
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- In this longitudinal study, subjects will be recruited from the patient population of the orthopaedic outpatient clinic of the Clinic and Polyclinic for Orthopaedics and Trauma Surgery at the University Hospital Bonn. A total of 300 patients will be included. This explorative study design is based on the number of cases and the number of operations performed in recent years at the University Hospital Bonn, which amounts to approx. 550 arthroplasty operations per year.
Key inclusion criteria (3 listed)
- There is an indication for primary knee or hip replacement or revision.
- The subject is over 18 years of age.
- Written consent is given if the subject is fully responsible.
Key exclusion criteria (4 listed)
- A known pregnancy
- A known mental or pain-associated illness
- Illness of an airborne infectious disease with an increased risk of mortality and morbidity
- Patient intolerances or restrictions that make participation in the study impossible
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Joint replacementAlso: Endoprothetics, ArthroplastyPatients routinely receive a joint replacement. | Procedure or surgery | Primary hip prosthesis, Primary knee prosthesis, Revision hip prosthesis, Revision knee prosthesis |
Primary outcome
SF 12 Questionnaire
Time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Health-related quality of life assessed by the SF-12 (score for physical components (PCS) and total score for mental components (MCS) - higher values mean better health, lower values mean worse health with a statistical mean of the total score of 50 (SD 10) (1-100)
Hand-held dynamometer
Time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Hand grip force using a hand dynamometer in absolute values (in kg).
Dual-Energy X-Ray Absorptiometry
Time frame: preoperative (approx. 1Day)
Bone density values by DXA measurement (T- or Z-values as deviation of the measured value from predefined mean values. T-Score ≤ -1 = osteopenia; T-Score ≤ -2,5 = osteoporosis.
Dual-Energy X-Ray Absorptiometry
Time frame: preoperative (approx. 1Day)
Body composition in relation to the lean mass. Fat Mass and Lean mass (gram).
Dual-Energy X-Ray Absorptiometry
Time frame: preoperative (approx. 1Day)
Fat Mass in percent.
5 secondary outcomes
Joint examination (HJHS)
Time frame: preoperative (approx. 1Day)
Hip examination (Harris Hip Score)
Time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Knee examination (Knee Society Score)
Time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Blood samples
Time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative
Biomaterial
Time frame: during operation
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Sep 2026.
- Individual participant dataSharing planned: No. The publication of anonymous patient data is not allowed by informed consent.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Andreas C. Strauss, PD Dr. med. principal investigator
University Hospital, Bonn
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Surgery and Knee Arthropathy, run by University Hospital, Bonn at 1 site in Germany.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 2 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Germany. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Andreas C. Strauss, PD Dr. med. (+4922828714176, andreas.strauss@ukbonn.de), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
SF 12 Questionnaire (time frame: preoperative (approx. 1Day), postoperative (approx. 7 Days), 6-8 weeks postoperative). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Sep 2026.