Immune response inhibition by irrigating subchondral bone with cytotoxic agents

Attempts have been made (in the recent past) to inhibit the immune response to fresh osteoarticular (shell) allografts because the occurrence and the magnitude of this response is considerably greater and more harmful than that seen after frozen bone and soft tissue allografts. To decrease in immunogenicity of these fresh grafts, the subchondral bone of rat distal femur allografts was irrigated with Betadine scrub solution (n = 10) or Triton-X (n = 11) before transplantation (Study 1). The Triton-X significantly reduced the immunogenicity of the grafts, but the Betadine scrub solution had no effect. A similar experiment with Triton-X was done in sheep where trochlear knee autografts (n = 3) were compared with unirrigated allografts (n = 3) and allografts receiving irrigation with Triton-X (n = 3) (Study 2). All 3 Triton-X irrigated allografts had no immune response, and showed much improved grafts compared with the control allografts (where an immune response developed in 2 of 3). Neither of the 2 allograft groups were as good as the autografts. These techniques may prove useful for inhibiting the recipient immune responses to fresh osteoarticular allografts in humans requiring partial joint reconstruction.