Investigation of a Customized Femoral Resurfacing Implant

The implant's safety profile will be assessed by incidence of any subject having any of the seven identified implant-related clinical undesirable side effects. This will be analyzed with a one-side exact binomial test on significance level 0.05, at 24 months post-operatively.

Inclusion criteria

• Male or female
• Age 30 ≤ 65 years
• Chondral defects of the femoral cartilage ICRS grade 3 (severely abnormal cartilage defects > 50% of the cartilage depth) or grade 4 (severely abnormal, through the cartilage depth) on medial or lateral femoral condyles
• Cartilage lesion area < 3.2 cm2 (diameter < 2 cm)
• Failed earlier conservative or surgical interventions such as lavage, abrasions, drilling or microfracture
• VAS-pain symptom >40 for more than 6 months
• The arthroscopic finding corresponds to the expected; size of cartilage lesion is correct and no other significant pathology (see CIP, "Intra-operative check-list", Appendix I)
• Capable of completing self-administered questionnaires
• Willing to comply with the follow-up requirements of the study
• Signed informed consent

Exclusion criteria

• BMI ≥ 35 kg/m2 (severe obesity)
• Instability or deficiency of soft tissues, vascular or muscular insufficiency
• Metabolic disorders which may impair bone formation
• Diabetes mellitus
• Smokers
• Diagnosis of a concomitant knee injury which the Investigator appreciates may interfere with study participation (i.e. may confound efficacy assessment or healing at the involved knee joint level)
• Irresolvable joint pain or loss-of-function with an undeterminable cause
• Diagnosis of a concomitant meniscal injury in involved knee that requires surgical intervention
• Loss of joint space on standing radiographs (≥ 1 on Ahlbäck-scale (0-5))
• Avascular necrosis
• Infections, systemic or local
• Known metal allergies
• History of inflammatory arthritis
• Pregnancy
• Pacemaker implant
• History of drug or substance abuse
• Systemic administration within 30 days prior to the study of any type of corticosteroid, antineoplastics, immune stimulating or immunosuppressive agents
• Participation in another clinical trial using an investigational new drug or device within 30 days of entrance into this study.
• Condition that may have an impact on the outcome of the investigation as judged by the Investigator.