P080 - Osteo-chondroisation: a clinical working hypothesis for pure cartilage defects in the knee. Mid term results of a pilot study.
Abstract
Purpose
Good long term results (Kusano, 2012) using the AMIC procedure in OCD’s of the femoral condyles have stimulated us to prospectively apply the same principles in pure chronic cartilage lesions of the patellofemoral joint (PFJ).
Methods and Materials
First the lesion is transformed in an osteochondral defect by removal of the sclerotic subchondral plate 4 mm deep, similar to Ficat (1979) in his “spongiolisation” procedure. It is then filled with gently crushed fresh cancellous bone retrieved from the tibia or distal femur, flush to the neighbouring subchondral plate. A bilayer Collagen I/III membrane is sutured over it. Concomitantly, alignment procedures for patella instability are performed.
Results
We report 5 cases, with ICRS grade 4 patellar lesions and severe PFJ instability. All received deepening trochleoplasty, tibial tubercle transfer, lateral Z plasty, medial patellofemoral reconstruction, and Osteo-chondroisation. Mean follow up was 3.8 years. Lesion size 3.9 ±1.7 cm2. Pain on VAS decreased from 6.4 to 2.8 postop . Kujala score improved from 40.8 to 70.2. One case developed arthrofibrosis, requiring artholysis. Postoperative MRI at 6, 12 and 36 months have shown complete filling of the defect, complete integration to the grafted bone with reformation of the subchondral plate, and homogeneous tissue with Dual T2 FSE isointense signal in 4 cases (Fig 1).
Conclusion
We present a pilot study testing the efficiency af a simple single step surgical treatment of grade 4 cartilage defects in the knee. Its strength would be a spontaneous repair response from the bone-marrow spaces. Cancellous bone is a source of MSC’s that can differentiate in osteogenic and chondrogenic liners according to their localization. Since a sclerotic subchondral plate is a barrier for vascularization, its removal combined with a stem-cell rich bone graft is a prerequisite for substantial fibrocartilage regeneration. The weakness of this unconventional series is of course its small sample .
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