Matrix-induced autologous chondrocyte implantation (MACI) has
demonstrated encouraging clinical results in the treatment of knee
chondral defects. However, earlier studies suggested that
chondrocyte implantation in the patellofemoral (PF) joint was less
effective than in the tibiofemoral (TF) joint.
To compare the radiological and clinical outcomes of those
undergoing MACI to either the femoral condyles or PF joint.
Cohort study; Level of evidence, 3.
A total of 194 patients were included in this analysis, including
127 undergoing MACI to the medial (n = 94) and lateral (n = 33)
femoral condyle, as well as 67 to the patella (n = 35) or trochlea
(n = 32). All patients were evaluated clinically (Knee injury and
Osteoarthritis Outcome Score [KOOS], visual analog scale, Short
Form-36) before surgery and at 3, 12, and 24 months after surgery,
while magnetic resonance imaging (MRI) was undertaken at 3, 12, and
24 months, with the MOCART (magnetic resonance observation of
cartilage repair tissue) scoring system employed to evaluate the
quality and quantity of repair tissue, as well as an MRI composite
score. Patient satisfaction was evaluated.
No significant group differences ( P > .05) were seen in
demographics, defect size, prior injury, or surgical history, while
the majority of clinical scores were similar preoperatively. All
clinical scores significantly improved over time ( P < .05), with
a significant group effect observed for KOOS activities of daily
living ( P = .008), quality of life ( P = .008), and sport ( P =
.017), reflecting better postoperative scores in the TF group. While
the PF group had significantly lower values at baseline for the KOOS
activities of daily living and quality of life subscales, it
actually displayed a similar net improvement over time compared with
the TF group. At 24 months, 93.7% (n = 119) and 91.0% (n = 61) of
patients were satisfied with the ability of MACI to relieve their
knee pain, 74.0% (n = 94) and 65.7% (n = 44) with their ability to
participate in sport, and 90.5% (n = 115) and 83.6% (n = 56)
satisfied overall, in the TF and PF groups, respectively. MRI
evaluation via the MOCART score revealed a significant time effect (
P < .05) for the MRI composite score and graft infill over the
24-month period. While subchondral lamina scored significantly
better ( P = .002) in the TF group, subchondral bone scored
significantly worse ( P < .001). At 24 months, the overall MRI
composite score was classified as good/excellent in 98 TF patients
(77%) and 54 PF patients (81%).
MACI in the PF joint with concurrent correction of PF maltracking if
required leads to similar clinical and radiological outcomes
compared with MACI on the femoral condyles.