Introduction: The treatment of distal femoral cartilage defects using autologous chondrocyte implantation (ACI) and matrix-guided autologous chondrocyte implantation (MACI) is become increasingly common. This prospective 7-year study reviews and compares the clinical outcome of ACI and MACI.

Methods: We present the clinical outcomes of 159 knees (156 patients) that have undergone autologous chondrocyte implantation from July 1998. One surgeon performed all operations with patients subsequently assessed on a yearly basis using 7 independent validated clinical, functional & satisfaction rating scores.

Results: Modified Cincinnati, Patient Functional Outcome and Lysholm & Gilchrist clinical rating scores all showed significant improvements compared to pre-operative levels (p< 0.0001). Although ACI scores are superior at one year (p< 0.05) there is no significant difference between ACI and MACI at 2 years.

Visual Analogue Score and Bentley Functional rating score showed significant improvements compared to pre-operative levels (p< 0.0001) with ongoing yearly sequential improvement.

Patient Rating and Brittberg scores, both subjective patient scores, similarly showed continuing improvements in the years following surgery.

Discussion: ACI and MACI produce significant improvements in knee function when compared to pre-operative levels with continued sequential improvement in outcomes for up to seven years. The initial data suggests a superior rate of clinical improvement using the MACI technique