An observational study in Total Knee Replacement, sponsored by I.R.C.C.S Ospedale Galeazzi-Sant'Ambrogio. Recruiting at 3 sites in Italy. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-11.
Sponsored by I.R.C.C.S Ospedale Galeazzi-Sant'Ambrogio · Observational
The study wants to evaluate the performance of this EM guide in comparison to a traditional IM guide.
75 patients will be included in the extramedullary group (to be compared with a corresponding previous group of 75 patients treated with intramedullary guide).
Total Knee Arthroplasty (TKA) is a widely performed surgical procedure aimed at relieving pain and restoring function in patients with advanced knee arthritis. The success of TKA is contingent upon precise implant positioning, particularly in relation to the femoral component. The femoral component's alignment significantly influences postoperative knee biomechanics, patient satisfaction, and long-term implant survival.
Conventional methods for femoral component positioning involve the use of intramedullary (IM) guides, which are inserted into the femoral canal to align the cutting block for bone preparation. While IM guides offer precise alignment, they can also lead to complications such as intraoperative fractures, fat embolism, activation of coagulation and excessive blood loss.
To address these limitations, extramedullary (EM) guides have emerged as an alternative option. EM guides are placed on the external surface of the femur without entering the medullary canal and avoiding complications that may occur reaming the canal.
In the recent past years, kinematic alignment (KA) has become widespread in use as a new technique for TKR that considers the patient's individual alignment and biomechanics. By restoring the pre-arthritic kinematic axes of the femur and tibia, KA aims to mimic the natural knee joint's function and movement.
In this study a specific EM guide - Anterior Cortex Stylus - is used to address the alignment of the femoral component in the context of a KA approach. The guide uses the anterior cortex of the distal femur as reference for cutting block positioning. The study aims to evaluate the performance of this EM guide in comparison to a traditional IM guide (used in previous group of patients).
This is an open, multi-centre, retro-prospective, observational, controlled study.
The primary aim is to evaluate whether the Anterior Cortex Stylus (in a retro-prospective collected series) is not inferior to the traditional intramedullary guide (previous group of patients) in term of positioning of the femoral component in TKA.
A total of 75 patients will be included in the extramedullary group (to be compared with a corresponding previous group of 75 patients treated with intramedullary guide). Both groups will be treated with a total knee arthroplasty using GMK Sphere (CE marked, class III) and a kinematic alignment approach.
I.R.C.C.S Ospedale Galeazzi-Sant'Ambrogio is the lead sponsor of 160 studies on the registry; 59 are open to participants now.
Counted across the registry records on this site, refreshed daily.
The study shall include a total of 150 patients: 75 will be included in the extramedullary group, to be compared with a corresponding previous group of 75 patients treated with intramedullary guide. Patients meeting the inclusion criteria (mentioned below) will be recruited separately by each participating institution.
Patient enrolled in the retrospective analysis have been operated upon between January 2021 and September 2025.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
patients trated with extramedullary (EM) guides. This cohort can be both Retroprospective and Prospective
patients trated with intramedullary (IM) guides. This cohort will be only Retrospective
Anterior Cortex Stylus
Radiographic angle at 3 moth post-op of the femoral component in TKA in an Anterior Cortex Stylus (retro-prospective collected series) compared to intramedullary guide (previous group of patients)
Time frame: Radiographic angle at 3 moth post-op in the sagittal plane, between the anterior cortex of the distal femur and the femoral component and compare it in the group operated with Anterior Cortex Stylus versus the group operated with IM guide.
Results across study centres
Radiographic angles compared between the centres (at pre-op, surgery and 3 month post-op)
Time frame: Compare the results in terms of radiographic sagittal angle between study centres at pre-op, surgery and 3 month post-op.
Adverse Events to determinate Instrument safety
Number of: adverse events, adverse device effects, serious adverse events and serious adverse device effects
Time frame: During surgery
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Plan to share: Undecided
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