safety and efficacy study of hytop® in the treatment of focal chondral defects.

Conditions: Focal Chondral Defect in Femoro-tibial Compartment of the Knee Joint

Summary: the two-layer bioresorbable hytop® matrix consists of an upper layer of highly purified porcine splint-skin which contains natural pores, and a lower layer of highly purified collagen fleece containing hyaluronan (ha). in this study, the medical device will be used and evaluated in a one-step procedure combining microfracturing with surgical implantation of hytop®. hytop® will support haemostasis in the articular cartilage defect, act as a support for cell growth and as a three-dimensional scaffold for cell differentiation. hytop® will protect the underlying tissue after cartilage debridement and/or microfracturing of the subchondral bone. the primary working hypothesis is that hytop® is safe and suitable as a cell-free matrix to support haemostasis, as a cover for the cartilage lesion and eventually to enhance cartilage regeneration in a one-step surgical procedure.


Eligibility criteria:
inclusion criteria: * male and female patients between 18 and 50 years of age. * good general health condition. * signed written informed consent. * general anaesthesia is justifiable for the patient from the medical point of view. * focal chondral defects involving the femorotibial compartment of the knee joint localised in only one compartment and not larger than the size of one hytop® patch. * isolated one-sided chondral lesion. * cartilage defect classified as outerbridge grade 3 or 4. * chondral lesions not exceeding through the subchondral bone (intact subchondral bone). * nearly intact chondral structure surrounding the defect, specifically outerbridge grade 2 or less. * corresponding joint area classified with maximum outerbridge grade 2. * clinical symptoms in the target joint (pain on walking 100 m of more than 4 on an 11-point numerical scale or swelling or locking or 'giving way'). * ensured compliance of subjects over the whole study period. exclusion criteria: * treatment with any investigational product within 4 weeks prior to study entry. * patients with known hypersensitivity to the constituents of the product or any component or procedure used in the study. * patients with previous treatment of the study relevant defect site. * cartilage lesion is not intact shouldered, has bipolar or corresponding involvement or bipolar 'kissing' lesions. * necessity of cartilage repair treatment at bilateral joints. * patients with meniscus lesions, total or partial (more than 1/3 of total volume) resected meniscus, limited joint mobility, varus/valgus joint malalignment of more than 5 degrees or insufficient ligament support. * inflammatory joint diseases (e.g. rheumatoid arthritis, bechterew disease, chondromatosis). * infection at study relevant site. * osteoarthritis, arthrofibrosis or haematopoetic related diseases. * study relevant metabolic disease, adipositas (bmi equal to or greater 30 kilogram per square meter). * study relevant neoplastic, neurological or mental illness. * study relevant autoimmune disease. * patients with elevated risk of bleeding. * recent history of drug and/or alcohol abuse (within the last 6 months). * pregnant or lactating females. * participants of childbearing age (pre-menopausal) who do not accept the use of methods of birth control with pearl index more than 1% (e.g. oral contraceptives, vaginal ring, hormone-releasing intrauterine device (iud), implants, depot syringes, hormone patch, double barrier method, tubal ligation, vasectomised partner,...) during the treatment period and the first 12 weeks of follow-up period. * subjects unable to understand informed consent or having a high probability of non compliance to the study procedures and/or non completion of the study according to investigator's judgement (e.g. illiteracy, insufficient knowledge of local language). * subjects not capable of contracting and of understanding the nature, risks, significance and implications of the clinical investigation and unable to form a rational intention in the light of these facts. * low probability of compliance with after-care rehabilitation scheme. * forbidden concomitant treatment affecting the evaluation of study parameters (e.g. oral intake of chondroitin sulfate, glucosamine, piascledine, other i.a. treatments like depot corticosteroids or arthroscopic procedures).

Keywords: cartilage tissue engineering hyaluronan hyaluronic acid