Compensation of surgical technique rotational alignment variations in total knee arthroplasty
| ISRCTN | ISRCTN66642689 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN66642689 |
| ClinicalTrials.gov (NCT) | Nil known |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | AC-14-033 |
| Sponsor | Hospital Universitari Germans Trias i Pujol |
| Funder | Germans Trias i Pujol Universtity Hospital |
- Submission date
- 25/10/2025
- Registration date
- 17/11/2025
- Last edited
- 17/11/2025
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Surgery
Plain English summary of protocol
Background and study aims
Total knee replacement surgery (also called total knee arthroplasty) helps people with severe knee arthritis regain mobility and reduce pain. During surgery, the position and rotation of the artificial joint parts can vary depending on the surgical technique used. These small differences in alignment may affect how the knee feels and functions.
This study compares three surgical techniques for total knee replacement to find out how each affects the rotation of the knee components and whether these differences influence recovery and function two years after surgery.
Who can participate?
Adults with painful knee osteoarthritis who need total knee replacement surgery and have not improved with non-surgical treatments can take part. People with previous fractures or bone surgery around the knee are excluded.
What does the study involve?
Participants are randomly assigned to one of three surgical groups:
-Measured Resection (MR) – the standard technique.
-Gap Balancing with Computer-Assisted Surgery (GB-CAS) – uses a computer to guide bone cuts.
-Gap Balancing with Force-Sensor Soft Tissue Balancing (FS-STB) – uses sensors to measure ligament pressure.
All patients receive the same type of cemented knee implant. CT scans and X-rays are taken before and after surgery to measure the implant positions. Patients are followed for two years and complete knee function and pain questionnaires (Knee Society and WOMAC scores).
What are the possible benefits and risks of participating?
There may be no direct personal benefit, but the findings could help improve surgical accuracy and future patient outcomes. Risks are minimal and limited to extra imaging and assessment time. Surgical risks are the same as for any standard knee replacement.
Where is the study run from?
The study is run from Germans Trias I Pujol University Hospital (Spain), Orthopaedic Surgery Department, in collaboration with the Radiology Department.
When is the study starting and how long is it expected to run for?
Recruitment began in 2015 and finished in 2017. Participants are followed for two years after surgery.
Who is funding the study?
This study has no external funding. It is being carried out as part of institutional clinical research.
Who is the main contact?
Name: Jose´A Hernández-Hermoso
Position: Orthopedic Surgeon
Institution: Germans Trias I Pujol University hospital
Email: jahernandezh.germanstrias@gencat.cat
Contact information
Public, Scientific, Principal investigator
Germans Trias i Pujol University hospital
Badalona. Barcelona
08916
Spain
 ORCID ID |
0000-0002-9167-3782 |
|---|---|
| Phone | +34 93497 8880 |
| jahernandezh.germanstrias@gencat.cat |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Interventional prospective randomized study |
| Secondary study design | Randomised controlled trial |
| Scientific title | Different femoral and tibial rotation alignment among measured resection and gap-balanced total knee arthroplasty is compensated by the soft tissue envelope resulting in similar combined knee rotation and clinical outcomes |
| Study acronym | RATKA study |
| Study objectives | We hypothesized that the measured resection technique, gap-balanced computer-assisted surgery and gap-balanced technique using a force-sensor soft tissue balancing device for achieving both mechanical and rotational alignment in TKA will result in some variation in native knee rotational alignment. We anticipate that the differences in femoral, tibial, and combined TKA rotations will be insufficient to significantly affect the 2-year clinical outcome scores. |
| Ethics approval(s) |
Approved 27/03/2015, Comitè Ètic Hospital Universitari Germans Trias i Pujol (Carretera Canyet s/n, Badalona. Barcelona, 08916, Spain; +34 93 4978880; ceic.germanstrias@gencat.cat), ref: AC-14-033 |
| Health condition(s) or problem(s) studied | Total Knee Arthroplasty surgical techniques in primary osteoarthritis patients |
| Intervention | Sixty patients were randomly assigned to one of three groups, with 20 patients in each group. A simple random sampling method was used -sealed envelopes-. All three groups underwent mechanically aligned TKA. The first group (MR group) underwent the measured resection technique, the second group (GB-CAS group) underwent gap balancing with CAS, and the third group (FS-STB group) underwent gap balancing with a force-sensor soft-tissue balance device. Follow up for 6 months. |
| Intervention type | Procedure/Surgery |
| Primary outcome measure(s) |
1. Femoral component rotation is measured using Berger’s femoral component rotation angle (BFA) on non-contrast-enhanced helical 2D-CT scans at 1–2 months preoperatively and 6 months postoperatively |
| Key secondary outcome measure(s) |
Clinical assessment using the Knee Society Score (KSS), WOMAC score at 1–2 months preoperatively and 6 months postoperatively |
| Completion date | 31/12/2017 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Mixed |
| Lower age limit | 55 Years |
| Upper age limit | 85 Years |
| Sex | All |
| Target sample size at registration | 60 |
| Total final enrolment | 55 |
| Key inclusion criteria | Patients with painful primary osteoarthritis who were unresponsive to nonoperative treatments and scheduled for TKA. |
| Key exclusion criteria | Patients with a history of femoral or tibial fractures or previous tibial or femoral osteotomy were excluded to avoid potential alterations in rotational alignment. |
| Date of first enrolment | 23/04/2015 |
| Date of final enrolment | 31/12/2015 |
Locations
Countries of recruitment
- Spain
Study participating centre
Badalona. Barcelona
08916
Spain
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Available on request |
| IPD sharing plan | The datasets generated during and/or analysed during the current study will be available upon request from Jose A Hernández-Hermoso, jahernandezh.germanstrias@gencat.cat |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Protocol file | in Spanish | 03/11/2025 | No | No |
Additional files
- 48285 Protocolo PTR 1.3.pdf
- in Spanish
Editorial Notes
03/11/2025: Trial's existence confirmed by Comitè Ètic Hospital Universitari Germans Trias i Pujol.
