Timothy M. Simon

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Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile(More)
Articular cartilage defects that are symptomatic and refractory to nonoperative treatment represent a clinical management challenge. Although there have been important advances in stimulating intrinsic repair mechanisms, cartilage regeneration, and other substitution techniques, to date none has unlocked the understanding necessary to duplicate normal(More)
One hundred nine patients over a 3 year period underwent reconstruction for chronic ACL ruptures using a freeze-dried, ethylene oxide-sterilized bone-patella tendon-bone allograft. Seven patients (6.4%) developed a characteristic persistent intraarticular reaction. This reaction was characterized by persistent synovial effusion with collagenous particulates(More)
UNLABELLED Fibrochondrocytes synthesize and maintain the extracellular matrix responsible for the distinctive material and structural properties of a normal meniscus. Viable meniscal cells are believed to be necessary for the long-term maintenance of these properties in meniscal allografts. The purpose of this study was to determine if the donor cells(More)
We developed an in situ freeze-thaw model designed to simulate an ideally placed and oriented autogenous graft of the anterior cruciate ligament. In this model, the anterior cruciate ligament was exposed, and the femoral insertion, tibial insertion, and body of the anterior cruciate ligament were frozen in situ with specially designed freezing probes.(More)
A comparative study of three subgroups of meniscal transplants was undertaken in the goat model: Group 1 (autograft) involved removal and immediate reimplantation of the meniscus; Group 2, fresh meniscal allografts; and Group 3, cryopreserved (30 days) meniscal allografts. Six months after surgery, tissues were evaluated for gross degenerative changes,(More)
One ACL in each of 11 mature goats was replaced with a freeze dried bone-ACL-bone allograft and a ligament augmentation device (LAD). The LAD was released from its tibial fixation at 3 months postoperation. Biomechanical, microvascular, and histological changes were evaluated 1 year following implantation. The reconstructed knees had a significantly greater(More)
The symptomatic degeneration of articular cartilage and associated arthritis is among the most prevalent chronic conditions in the United States and the population most at risk is increasing. It is the leading cause of limitations in activities of daily living and is second to heart disease in causing work disability. The current and future socioeconomic(More)
The aging human population is experiencing increasing numbers of symptoms related to its degenerative articular cartilage (AC), which has stimulated the investigation of methods to regenerate or repair AC. However, the seemingly inherent limited capacity for AC to regenerate persists to confound the various repair treatment strategies proposed or studied.(More)
The aim of this study was to evaluate a new collagen-GAG-calcium phosphate biphasic scaffold for the repair of surgically created osteochondral defects in goats. Comparison of morphological, histological and mechanical performance of the repair tissue was made with defects repaired using a synthetic polymer scaffold. Defects were created in the medial(More)