Autogenous tendon graft substitution for absent knee joint meniscus: a pilot study

The purpose of this pilot study was to explore the potential of an autogenous tendon graft to substitute for an absent human knee joint meniscus. Based on the results of animal studies and human reports, it was hypothesized that autogenous tendon tissue would substitute for human knee joint meniscus: maintain mechanical integrity, convert to fibrocartilage, preserve the joint compartment, and provide symptomatic relief for the patient. Five patients, 2 men and 3 women, average age 41 years, had surgical absence of the lateral meniscus, genu valgum, and severe degenerative arthritis of the lateral compartment, but a stable knee. All patients were offered alternative treatments: do nothing, medication, arthroscopic debridement, osteotomy, and knee replacement. The operations were performed by arthroscopy. An accompanying arthroscopic debridement procedure was performed in the same compartment. In 4 cases, the donor graft was the semitendinosus tendon. In 1, the patellar tendon was used because the semitendinosus had been previously used in an anterior cruciate ligament reconstruction. Four of the 5 patients had a second-look arthroscopy and biopsy between 9 and 24 months. There was partial physical integrity to the tendon graft. The tendon graft did not completely convert to fibrocartilage. The joint surface was not preserved. Only 1 patient had minimal clinical improvement; the others were not improved. No patient was made worse. One patient had a total knee replacement 1 year later. Another had a knee fusion after 4 years. All other patients are considering future reconstructive surgery. The autogenous tendon graft as used in this pilot study was not successful as a substitute for an absent meniscus. The hypothesis was not realized. The observations from this pilot study should be helpful in future study protocol design.