The clinical study was stopped due to very low enrolment numbers. Due to the very slow enrolment, the goal of the study cannot be reached within a reasonable time frame.

The goal of this study is to establish the accuracy of the new X-PSI Knee System guides by analyzing early postoperative (4-6 weeks) imaging data with regards to the mechanical alignment and compare them with preoperative planning imaging data. Mechanical alignment in the hip-knee-ankle (HKA) frontal plane with X-PSI Knee System will be measured and compared with results reported in the literature using a conventional (non-guided) approach.

Hypothesis: The use of the new X-PSI Knee System achieves the same accuracy with respect to mechanical alignment as with conventional instrumentation.

Patient-specific instruments (PSI) provide surgeons with an anatomically personalized surgery tool. The newly developed and CE-marked X-PSI Knee System is based on long leg x-rays that are used to generate a pre-operative 3D model of the knee. The total knee replacement surgery will be planned according to this 3D model.

The aim of this multi-center, prospective, non-controlled post-market study is to scientifically document the accuracy, cost-effectiveness and subsequent clinical performance of the X-PSI Knee System. The X-PSI pin guides are designed to facilitate a more simplified, efficient and customized TKA procedure compared to conventional, non-guided instrumentation.

To evaluate the accuracy of the X-PSI Knee System, early postoperative (4-6 weeks) imaging data will be analysed with regards to the mechanical alignment (hip-knee-ankle angle) of the leg and matched to preoperative planning imaging data. The X-PSI Knee System cohort will then be compared with current literature (70% of cases within ±3 degrees) where patients were conventionally operated with non-guided surgery. No control group will be studied.

The cost-effectiveness of the X-PSI Knee System will be evaluated with an efficiency matrix to record OR set-up time, surgery time and post-processing time.

Clinical outcome data of the patients will be evaluated 4-6 weeks and 1 year post-surgery with the help of patient questionnaires (VAS pain scale, EQ-5D and Oxford Knee Score), a physical exam and the assessment of radiographs.

The study population will be compromised of males and females requiring total knee arthroplasty and satisfy the inclusion/exclusion criteria. The study will last one (1) year from the time of surgery. The collected data aim to improve the treatment and quality of life of patients suffering from degenerative joint diseases. In addition, shorter surgery times possibly result in reduced risk of infection, decreased time of anaesthesia and better cost-effectiveness.

Inclusion Criteria:

• Patient is 18 years of age or older.
• Patient can follow the X-PSI Knee System imaging protocol as part of standard of care procedures.
• Patient gets TKA treatment which follows the criteria of the appropriate Instruction for Use.
• Patient is willing and able to cooperate in the required postoperative standard of care.
• Patient is willing and able to complete scheduled follow-up evaluations as described in the Informed Consent.
• Patient has participated in the study-related Informed Consent process and has signed the Ethics Committee approved Informed Consent

Exclusion Criteria:

• Patient is unwilling or unable to give consent or to comply with the follow-up program.
• Patient meets exclusion criteria of the appropriate Instruction for Use
• Patients who have any condition which would in the judgement of the Investigator place the patient at undue risk or interfere with the study. Any patient who is institutionalized, or is a known drug abuser, a known alcoholic or anyone who cannot understand what is required from them
• Patient is known to be pregnant

Baseline data collected and reported for those participants that underwent surgery with X-PSI Knee System

1 year starting from day of surgery

Adverse Event data collected and reported for those participants that underwent surgery with X-PSI Knee System

The study was prematurely terminated due to slow enrloment. Only 3 subjects were operated with X-PSI. Out of the 3 subjects, 2 reached the final 1 year follow-up. Due to the very low number of subjects, no statistical analysis was conducted on the data.