Intra-articular histopathologic changes secondary to local lead intoxication in rabbit knee joints

To study the effects of intra-articular lead fragments on articular cartilage, synovium, and menisci in rabbit knees.

Animal model.

Cylindrical lead implants were inserted into a nonarticulating area of the medial femoral condyle. Identically sized stainless steel implants were used as a control for the mechanical effects of the material, and arthrotomies were performed on some of the animals as a control for the effects of surgery.

Histologic evidence of articular degeneration was significantly greater in rabbit knees implanted with lead compared with knees with steel implants (p = 0.0625), knees with arthrotomies, or those with no procedure performed (p = 0.0325). Changes were also greater in the synovium of knees implanted with lead compared with all other specimens. No significant degenerative changes were noted in the menisci of any specimen.

Such changes may be early signs of degenerative joint disease and may lead to chronic damage. Gunshot wounds affecting joints may cause intra-articular retention of lead fragments, which are not physiologically inert and may cause degenerative joint changes. Even if no mechanical impingement is evident, removal of lead may be warranted to prevent early arthropathies in humans.