SPHEROX (sphéroïdes de chondrocytes autologues humains associés à une matrice) - Réparation des lésions chez l’adolescent atteint d’ostéochondrite disséquante

Key points

Disapproval of reimbursement for the repair of symptomatic articular cartilage defects of the femoral condyle and the patella of the knee (International Cartilage Regeneration & Joint Preservation Society [ICRS] grade III or IV) with defect sizes of up to 10 cm² in adolescents presenting with epiphyseal growth cartilage closure at the affected joint.

Role in therapeutic strategy?

The short- and medium-term therapeutic endpoints are to repair the damaged cartilage while obtaining functional neoformed tissue, improve functional performances and the patient’s quality of life. The long-term objective is to prevent osteoarthritis of the knee.

There is a consensus to only envisage surgical treatment for unipolar (i.e. on a single face, which excludes symmetric osteoarthritis defects) symptomatic ICRS arthroscopic grade III and IV cartilage defects of the knee, with no associated ligamental defects and no unfavourable axis defect (valgus, varus), occurring in younger subjects where obesity is absent or controlled.

The choice of procedure depends on patient age, defect size, cartilage status and patient-related factors such as previous history of cartilage repair, BMI, and functional demand.

In France, the most commonly used procedures are microfracture procedures and osteochondral grafting (mosaicplasty). Mosaicplasty is the standard of care for defects < 2 cm². For these small defects, microfractures alone may also be used. The microfracture “plus” or “AMIC” procedure

(associated with membrane implantation) or autologous chondrocyte transplantation are envisaged for defects of 2 to 4 cm².

Extensive substance loss > 4 cm² is rare and can also be treated with microfracture “plus” procedures. However, in the case of very deep defects affecting the subchondral bone, they require an allogeneic graft salvage procedure, despite including immunological and pathogen transmission risks, or the mega-OATS procedure (posterior condyle osteochondral graft as per Imhoff) rarely used in France, as it is the only option to restore femoral condyle convexity.

Role of SPHEROX in the therapeutic strategy:

Considering:

• the purely descriptive data available from two observational studies, with a low level of evidence in the light of the following methodological limitations:
  • subjective medical practitioner assessment of the primary outcome measure in an open-label study,
  • small sample of patients with osteoarthritis dissecans (OCD) with epiphyseal growth cartilage closure in these two studies,
• the lack of comparative data with respect to standard surgical procedures used in France for defects ≤ 10 cm² (mosaicplasty, microfractures “plus”, allografts, mega-OATS) and supportive care (immobilisation, medicinal pain treatments, rehabilitation), 
• the lack of usable quality-of-life data in view of the study methodologies,
• the limited follow-up in terms of efficacy and safety in the long term particularly for the prevention of osteoarthritis of the knee,
• the low level of evidence of the clinical benefit in adults.

The Committee deems that it is not possible to establish the role of SPHEROX 10-70 spheroids/cm², suspension for implantation, for the repair of symptomatic articular cartilage defects of the femoral condyle and the patella of the knee with defect sizes of up to 10 cm² in adolescents presenting with epiphyseal growth cartilage closure at the affected joint.