Norwegian Cartilage Project - Microfracture

114 patients between 18 and 50 years with an isolated focal cartilage defect in the knee will be randomized to either receive arthroscopic microfracture or arthroscopic debridement. Both groups will then undergo a systematic physiotherapy training regime for 6-9 months. The groups will then be compared for results, after 3, 6, 12 and 24 months, by using validated patient reported outcome scores (Lysholm, KOOS, Tegner) and EQ5D as well as clinical examination and radiological findings at 2 years (MRI).

Focal cartilage defects in the knee - A randomized controlled trial comparing arthroscopic microfracture with arthroscopic debridement.

Clinical compare the effect of arthroscopic microfracture (MF) with arthroscopic debridement (AD) in patients with symptomatic full thickness knee cartilage injuries less than 2cm2.

Focal cartilage injuries in the knee might have devastating effect both in the short term and in the long term. Various surgical treatment options are available, with microfracture the most used technique globally. Meta-analysis and systematic reviews have required well-designed, long-term, multicenter studies to evaluate clinical outcomes of microfracture with the use of a "no treatment" group as a control group.

H0: There is no difference in KOOS QoL after AM or AD 24 months after surgery. H1: There is a difference in KOOS QoL after AM or AD 24 months after surgery.

Questionnaires: KOOS, Tegner score, Lysholm score, EQ-5D, VAS. Physical examination: range of motion and hop test. Radiology: x-ray and MRI of the knee.

Primary aim: KOOS quality of life (QoL) subscore.

Prospective, double-blinded parallel-group multicenter study with 2 treatment arms. Approx. 24 months inclusion and 24 months follow up. In total 4 years.

All will be invited to participate in late controls after 5 and 10 years.

6 Norwegian hospitals: Akershus University Hospital, Oslo University Hospital - Ullevaal, Kristiansund Hospital, Aalesund Hospital, Diakonhjemmet Hospital and Haukeland University Hospital.

114 patients Inclusion: age 18-50 years old, single symptomatic cartilage defect on femoral condyle or trochlea.

2 treatment groups with 57 patients in each group. Follow up after 3 months (± 2 weeks), 6 months (± 4 weeks), 12 months (± 6 weeks) and 24 months (± 8 weeks). All will be invited to participate in late controls after 5 and 10 years. If any unforeseen complication outside normal clinical practice occurs, the sponsor representative will be contacted as soon as possible with a parallel message to the local coordinators at the involved hospitals. During each follow up, there will be a case report form (CRF) regarding complications and safety.

A 5 mL venous blood sample will be drawn on the day of operation. The blood sample will be centrifuged before serum is pipetted in a sterile tube. The serum will be analyzed at Oslo University Hospital - Rikshospitalet on the cartilage biomarker microRNA-140 (miR-140).

If normal distribution, aims will be analyzed using linear mixed models (LMM), and the primary aim will be performed as a post hoc test for the LMM, similar to performing a two-sample t-test. If no normal distribution, analysis will be performed using Mann-Whitney U-test.

Detecting a difference of 10 with 80 percent Power, uing a standard deviation of 18, this yields 52 patients in each group. By adding 10% due to loss during follow-up, we therefore plan to include a total of 114 patients.

No interim analysis will be done. Monitor from Health Møre and Romsdal HF. The end of this study is 24 months after the last included patient.

Eligibility Criteria:
Inclusion Criteria:

* Single symptomatic lesion of the trochlea, medial or lateral femoral condyle of the knee less than 2 cm2
* Cartilage lesion ICRS grade 3 or 4
* More than 50 % of the menisci intact
* Ligamentous stable knee
* Lysholm Score \< 75
* Acceptable range of motion (5-105 degrees)

Exclusion Criteria:

* Osteoarthritis
* Malalignment \> 5 degrees measured clinically, and if uncertainty on HKA radiographs
* Systemic arthritis
* Previous cartilage surgery except OCD fixation
* Obesity BMI \> 30
* Serious drig or alcohol abuse
* Inability to answer questionnaires or partake in rehabilitation
* Comorbidity that may influence surgery or rehabilitation
* Pregnancy