BackgroundThe enthesis, which attaches the tendon to the bone, naturally disappears with aging, thus limiting joint mobility. Surgery is frequently needed but the clinical outcome is often poor due to the decreased natural healing capacity of the elderly. This study explored the benefits of a treatment based on injecting chondrocyte and mesenchymal stem cells (MSC) in a new rat model of degenerative enthesis repair.MethodologyThe Achilles' tendon was cut and the enthesis destroyed. The damage was repaired by classical surgery without cell injection (group G1, n = 52) and with chondrocyte (group G2, n = 51) or MSC injection (group G3, n = 39). The healing rate was determined macroscopically 15, 30 and 45 days later. The production and organization of a new enthesis was assessed by histological scoring of collagen II immunostaining, glycoaminoglycan production and the presence of columnar chondrocytes. The biomechanical load required to rupture the bone-tendon junction was determined.Principal FindingsThe spontaneous healing rate in the G1 control group was 40%, close to those observed in humans. Cell injection significantly improved healing (69%, p = 0.0028 for G2 and p = 0.006 for G3) and the load-to-failure after 45 days (p<0.05) over controls. A new enthesis was clearly produced in cell-injected G2 and G3 rats, but not in the controls. Only the MSC-injected G3 rats had an organized enthesis with columnar chondrocytes as in a native enthesis 45 days after surgery.ConclusionsCell therapy is an efficient procedure for reconstructing degenerative entheses. MSC treatment produced better organ regeneration than chondrocyte treatment. The morphological and biomechanical properties were similar to those of a native enthesis.

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Structural properties and interfragmentary shear motion analysis demonstrated a much higher rigidity in the IN-bone than in the DCP-bone constructs.

Upper limb involvement in cerebral palsy is usually more complex than lower limb involvement. Each child has a specific brain lesion and the clinical pattern is highly variable. Current clinical methods of assessment do not fully evaluate the kinematic activity during simple activities of daily life. We defined an upper limb three-dimensional kinematic protocol in order to complete the clinical analysis of such patients and reproducibility tests are in progress. Data were presented for one of the patients studied and showed some important differences between the clinical analysis and the kinematic one. A three-dimensional upper limb motion analysis gives a more complete kinematic evaluation and should help better measure the results of treatments.