An observational study in Arthropathy and Knee Replacement, sponsored by Medacta International SA. Recruiting at 4 sites in 3 countries. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2025-09-29.
Sponsored by Medacta International SA · Observational
This is a Post-Marketing Surveillance of GMK SpheriKA knee stem prosthesis.
The aim of the current study is to collect clinical and radiological data to monitor the performances of the "GMK® SpheriKA" Knee Prosthesis implanted via the kinematic alignment technique.
386 studies on the registry are indexed under Joint Diseases; 64 are open to participants now.
This study's planned enrollment of 281 is above the median of 86 across 116 observational studies indexed under Joint Diseases.
Browse Joint Diseases studies →Medacta International SA is the lead sponsor of 46 studies on the registry; 18 are open to participants now.
Counted across the registry records on this site, refreshed daily.
281 participants are planned for the entire project (all sites combined). Patients requiring "GMK® SpheriKA" implanted via the kinematic alignment technique will be informed and enrolled during the preoperative visit.
The study is conducted as standard of care treatment and participants will receive the same treatment and undergo the same postoperative assessments as non-participants.
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.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
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.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The first objective is to study the FJS of patients who were implanted a "GMK® SpheriKA" knee prosthesis using the kinematic alignment technique
Primary objective will be evaluated with the Forgotten Joint score (FJS).
study the efficacy of the treatment to make the patient forget the presence of the artificial joint in everyday life. The Forgotten Joint Score assessment consists of 12 questions and is scored on a 0-100 scale. The higher the score, the less the patient is aware of their affected joint when performing daily activities
Time frame: 6 weeks, from 1 to 10 years annually
patient-reported outcomes 1
Oxford Knee Score: The OKS is a patient reported outcome measure that consists of 12 questions about an individual's level of function, activities of daily living and how they have been affected by pain over the preceding four weeks
Time frame: 6 weeks, from 1 to 10 years annually
Satisfaction and Expectations questionaires
Satisfaction and Expectations questionaires Patient reported satisfaction and expectations answering some questions of the "satisfaction and expectation knee society score", the goal is to collect all final answers and have an overview on how the patient feels. "Patient Expectations" is a three-question fifteen-point scale that is collected pre-operatively and post-operatively. "Patient Satisfaction" is a five-question 40-point scale that is collected preoperatively and at each follow-up visit.
Time frame: 6 weeks, from 1 to 10 years annually
Radiological outcomes
Radiological assessment including implant positioning, presence of radiolucent lines, subsidence, migration of components, presence of heterotopic ossifications or osteolysis
Time frame: pre-op, 6weeks, 1, 2,5,10 years
Adverse events
Adverse events (type of complications, dependent or not from the device etc)
Time frame: during surgical operation, 6weeks, 1,2,5,10 years
Limb alignment
Limb alignment will be measured: mMPTA (°), mLDFA (°) and joint line (HKA) will be recorded. HKA = Hip-Knee-ankle angle measured in degrees mMPTA = mechanical medial proximal tibial angle measured in degrees mLDFA = mechanical lateral distal femoral angle measured in degrees
Time frame: on preoperative and 6-week x-rays
Lateral uncoverage of the anterior femoral resection
Measurement of the lateral uncoverage of the anterior femoral resection measured in mm
Time frame: During Surgical Operation
Started Jul 2022 (actual). Primary completion is estimated for May 2035, 154 months after the start.
Of 58 observational studies under Joint Diseases, half reached primary completion within 62 months of starting (the median), counting those still running; a quarter within 28 and three quarters within 153. This study's planned 154 months is above that.
How these figures are worked out, and which studies are left out of them.
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