Arthroscopic arthrolysis for flexion contracture following intraarticular reconstruction of the anterior cruciate ligament.

This article describes the surgical technique and expected results for arthroscopic arthrolysis for the treatment of flexion contracture following anterior cruciate ligament (ACL) reconstruction. The technique emphasizes a systematic approach to the surgical procedure followed by an intensive rehabilitation program. The results in 11 patients treated with this technique are reviewed. They averaged 12.6 months from the index ACL reconstruction. Despite extensive physical therapy, their mean preoperative flexion contracture was 19 degrees, mean total range of motion was 94 degrees, and mean preoperative Lysholm score was 67. At a mean follow-up of 22 months following arthrolysis and physical therapy, mean flexion contracture improved to 2 degrees, total range of motion improved to 125 degrees, and mean Lysholm score improved to 94.

Intraarticular carcinogenesis bioassays of CoCrMo and TiAlV alloys in rats.

Wear-debris powders of cobalt-chromium-molybdenum (CoCrMo) and titanium-aluminum-vanadium (TiAlV) alloys, which are widely used for orthopedic implants (eg, hip and knee prostheses), were tested for carcinogenic activity following intraarticular administration (20 mg/rat) to groups of 44 male Fischer-344 rats (Charles River Breeding Laboratories, North Wilmington, MA). Control groups received similar intraarticular injections of either a noncarcinogen (manganese powder, negative control rats) or a potent carcinogen (nickel subsulfide powder, positive control rats). The experimental groups of 8-12 rats were observed for 24 months after injection. No local tumors developed at the injection site in the negative control rats or in rats that received the CoCrMo or TiAlV powders; poorly differentiated or pleomorphic sarcomas developed at the injection site in 10 of the 12 positive control rats that were treated with nickel subsulfide. Incidences of primary tumors distant from the injection site did not differ significantly among the experimental groups. This study shows that, under experimental conditions, any carcinogenic activity of CoCrMo or TiAlV wear-debris powders is weak in comparison to nickel subsulfide. Based on this study and observations in other laboratories, intraarticular administration of test materials to rats provides a practical, reliable, and biologically relevant method for carcinogenesis testing of biomaterials used for orthopedic implants.

Cobalt in periprosthetic soft tissue. Observations in 6 revision cases.

Cobalt (Co) was analyzed in sera obtained before surgery and in biopsies of periarticular soft tissue from 7 control patients undergoing primary total hip arthroplasty and from 6 Co-exposed patients who developed aseptic loosening of the femoral component after hip arthroplasty (CoCrMo alloy, greater than 59 percent Co, metal-on-plastic type). Serum-Co concentrations were not elevated in the Co-exposed patients compared with control patients or healthy adults. In 5 of the 6 Co-exposed patients, Co concentrations were greatly increased in periprosthetic tissue sections 0-1 mm from the synovial surface (median 2.4 [2.1-27] micrograms Co/g) compared with corresponding sections from the control patients (median 0.4 [0.1-0.6] microgram Co/g). Co concentrations diminished in tissue sections at successive distances of 2-3 and 4-5 mm from the synovial surfaces. In the Co-exposed patients, Co concentrations in sera and periprosthetic soft tissues were not correlated, indicating that serum Co concentration is not a reliable index of the Co burden in periprosthetic soft tissue.