Clinical Trial of an MRI Based Patient Specific Focal Knee Resurfacing Implant

Lesions in the cartilage are common disorders. In the knee, cartilage lesions are found in over 50 % of all arthroscopies, where 25 % of these are of focal character and the majority are found in the medial femoral condyle. The quality of life of patients with focal cartilage defects is significantly affected and it has been shown that the quality of life is affected to the same extend as in patients scheduled for knee replacement. Arthroscopy lavage and debridement micro fracturing, mosaic plasticity as well as osteochondral autograft transplantation (OATS) are methods used for treatment of the lesions. Some have shown to help the patients but there is an ongoing treatment gap especially for patients with knee lesions and early osteoarthritis.

Episurf Medical has developed a Focal Knee Resurfacing (FKR) implant, the Episealer® implant. The implant is used for treatment of focal cartilage lesions of the lateral or medial femoral condyle in order to alleviate pain and improve range of motion. The implant and surgical instruments are customized to each patient's joint anatomy, position, and size of injury, based on patient-specific images (MRI). The Episealer® device is CE marked.

The Episealer® implant consists of a peg and a hat. The implant exists in five different diameters (12,14,17, 20 and 25mm), depending on the lesion size. The shape of the hat is circular or oval.

The Episealer® implant is made of biocompatible cobalt/chromium/molybdenum alloy. To enhance the osseointegration, the implant is coated with biocompatible hydroxyapatite onto an interlaying biocompatible pure titanium coating.

A previous study (S57685) showed that Episealer is a viable option for focal cartilage lesions of the distal femur not responding, or not eligible for, biological treatment options (eg. microfracturing). This device is a good solution when there are no alternative treatments, except prosthesis surgery, available.

The goal is to evaluate the efficacy, safety and performance of the Episealer® device in a larger sample size and on the long term.

Inclusion criteria

• Subjects with a focal cartilage lesion of the distal femur in which biological surgical methods have failed or are not eligible
• Minimal age 18 years (Preferred age group >40 years)
• Suitable for implant, to be determined by analysis of MRI imaging. Suitability is set by the size and location of the lesion.
• Informed consent

Exclusion criteria

• Under age (<18yrs)
• Active or recent (<1 yr) septic arthritis of the involved knee
• Associated symptomatic untreated ligamentary or meniscal pathology in the involved knee
• (Severe) osteoarthritis in the involved or other compartments of the involved knee
• Severe osteoporosis
• MRI not possible (eg. due to pacemaker)
• Marked valgus- or varus alignment (>6 degrees)