Poster 227: Prospective Clinical and Radiological Follow-Up Beyond 10 Years in Patients Undergoing Matrix-Induced Autologous Chondrocyte Implantation (MACI) in the Patellofemoral Joint

Abstract

Objectives: Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of knee cartilage defects, though limited research is available on its longer-term (≥10 years) sustainability in the patellofemoral joint. This prospective study sought to present and report the clinical and radiological outcome beyond 10 years in a prospectively recruited cohort of patients undergoing MACI in the patellofemoral knee joint. Methods: The current study included 82 patients (patella = 41, trochlea = 41) assessed at ≥10 years following patellofemoral MACI. Patients were assessed preoperatively and at 2, 5 and ≥10 years via the Knee Injury and Osteoarthritis Outcome score (KOOS), the 36-item Short Form Health Survey (SF-36), the frequency (VAS-F) and severity (VAS-S) of knee pain, patient satisfaction, active knee range of motion (ROM) and peak isokinetic knee extensor and flexor torque. High-resolution magnetic resonance imaging (MRI) assessed pertinent measures of graft outcome as per the magnetic resonance observation of cartilage repair tissue (MOCART) system, as well as an overall MRI composite score. Results were analyzed according to the graft location (patella or trochlea). Results: While no statistically significant differences (p>0.05) were observed between those undergoing patella or trochlea MACI across the majority of demographic (age, weight, BMI), injury history (duration of symptoms) or surgery (defect size, prior procedures, requirement for concomitant patellofemoral re-alignment) variables, a significantly higher (p=0.013) proportion of males was seen in the trochlea MACI group. All patient-reported outcome measures significantly improved (p<0.05), with no differences observed between those undergoing patella or trochlea MACI. No group differences (p>0.05) were observed in active knee flexion or extension ROM between groups, though those undergoing patella (versus trochlea) MACI demonstrated significantly greater postoperative quadriceps (Figure 1) and hamstring strength limb symmetry indices. No statistically significant decline (p>0.05) was seen from 2 years to final follow-up in any MRI-based measure, with no MRI-based differences observed between patella (Figure 2) and trochlea (Figure 3) grafts. In the cohort assessed at ≥10 years post-surgery, 4 patients (patella n=2, trochlea n=2) demonstrated graft failure on MRI, though a further 3 patients (all trochlea) were omitted from ≥10-year review that had already progressed toward total knee arthroplasty. Conclusions: Good clinical scores, high levels of patient satisfaction and adequate graft survivorship were observed at ≥10 years following MACI to the patella or trochlea.