Purpose: Females are at greater risk for anterior cruciate ligament (ACL) injury than males. Soccer may be a significant risk factor for ACL injury in adolescent females. ACL injury has significant consequences, including early onset of osteoarthritis. The purpose of the study was to determine

the number of ACL reconstruction surgeries performed on females between the ages of 13–18 inclusive in the Capital Health (CH) region from December 2000 to November 2005, and

Secondly, we describe factors relating to the mechanism of injury.

Method: Utilizing regional administrative data, we performed a standardized chart review and telephone interviews with female adolescents who underwent ACL reconstruction in the aforementioned time period. Information gathered included:

Age at reconstruction procedure.

The Alberta Soccer Association provided the number of registrants in indoor and outdoor seasons over the same time period.

Results: 2,824 ACL reconstruction operations were performed between December 2000 and November 2005. Reconstructions in females took place at an earlier age than in males. There were 266 ACL reconstructions in 256 adolescent females, of which 253 charts were available for review. One hundred and eleven (44%) knees were injured during soccer play. Seven patients with eight ACL reconstructions who injured their ACL playing soccer could not be located. ACL injuries occurred during indoor soccer in 52 (51%) cases despite higher registration in outdoor soccer during the same time-frame. 77 (74%) subjects played competitively and 81 (79%) subjects played two or more times/week.

Conclusion: Approximately 10% of ACL reconstructions were performed on adolescent females. Nearly 50% of ACL injuries occurred during soccer play, with a similar number seen in indoor versus outdoor play. Study limitations include the use of administrative data to assess the number of ACL reconstructions rather than ACL injuries. An awareness of the propensity of knee injuries in female soccer players is important. With the increased participation of young females in soccer and the serious lifelong implications of ACL rupture, prevention and training should be improved to lower the incidence of injury.

Purpose: Current techniques for articular cartilage repair remain suboptimal. The best technique involves the introduction of cultured chondrocytes into the injury site. Experimental results of current chondrocyte culture and expansion techniques (passaging) have shown phenotypic alteration resulting in fibroblast-like cells. Therefore, treatment methods that propose the transplantation of cultured chondrocytes might be transplanting fibroblast-like cells instead of chondrocytes. This experiment explored the difference in genetic expression of chondrocytes left at confluence compared to chondrocytes that were passaged as performed in current culture techniques. It was hypothesized that chondrocytes left at confluence would maintain their collagen I and collagen II gene expression over time.

Method: Fresh normal human articular cartilage was collected from deceased donor patients. The matrix was digested and the chondrocytes were plated in monolayer to create two groups. The first group was cultured and passaged 2? at confluence seven times. The second group was cultured at confluence and left for seven weeks, with medium changes every 3–4 days without passaging. At weekly intervals RNA was extracted from cells in both groups and analyzed with real time PCR, probing specifically for the genes responsible for the production of collagen I, collagen II, aggrecan, and GAPDH. This was done in duplicate.

Results: Collagen II gene expression was maintained over seven weeks in cells left at confluence but was decreased in passaged cells. Collagen I gene expression decreased over seven weeks in cells left at confluence, but remained the same in passaged cells. Aggrecan gene expression remained the same in both groups.

Conclusion: Current culture and expansion techniques that employ passaging (as used in clinical scenarios) result in significant alterations in gene expression that are inconsistent with the current definition of a “chondrocyte”. Culturing chondrocytes at confluence can produce gene expression more similar to native chondrocytes but even these cells have expression of collagen type I that should not be present in chondrocytes. The results of this study suggest that further investigation is required to develop chondrocyte culture and expansion techniques that minimize the de-differentiation of chondrocytes by maintaining collagen II gene expression and eliminating/preventing collagen I gene expression.