Biomedical subjects

D L Butler

Publications and source records attributed to D L Butler.

94 records · Page 6Linked to original sources

PubMedDate not supplied

The effects of processing techniques on the mechanical properties of bone-anterior cruciate ligament-bone allografts. An experimental study in goats.

There has been a growing interest in the use of allografts as ACL substitutes. Allografts are often freeze dried to increase shelf storage time and sterilized with ethylene oxide. This study was conducted to determine the effect of a specific ethylene oxide sterilization procedure and freeze drying process on the initial mechanical properties of femur-ACL-tibia preparations. Twelve knees (stifle joints) from six mature goats were divided into two groups (one knee of pair to each group). Knees were cleaned of all soft tissue except for the anterior cruciate, posterior cruciate, and collateral ligaments. Group 1 was sterilized with ethylene oxide (simulating clean procurement) then freeze dried. Group 2 was freeze dried only (simulating sterile procurement). The knees were rehydrated and then tested in tension to failure to determine their structural mechanical properties. The ethylene oxide-freeze dried specimens (Group 1) had a mean maximum load before failure of 2059 +/- 273 newtons (N) (+/- SE) which was not statistically different than the maximum load of the freeze dried specimens (Group 2) of 2023 +/- 214 N. The average strength of Group 1 and 2 combined was not significantly different than a third group of 12 normal femur-ACL-tibia controls which had an average maximum force of 2403 +/- 133 N. No significant differences between the groups were observed for stiffness, energy to maximum strength, or elongation to maximum force. It appears the freeze dry processing, with or without ethylene oxide sterilization, using the procedure we used, has, at most, a small effect on the initial mechanical properties of the preparations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Intra-articular cruciate reconstruction. I: Perspectives on graft strength, vascularization, and immediate motion after replacement.

All of the factors discussed here hopefully will increase the success rate of future intra-articular grafts. But it should not be supposed that the ideal ACL substitution answer is immediately forthcoming. Past experience points to the inherent difficulty of any potential solution and the need to progress in a rigorous scientific manner in the evaluation of the next wave of ligament substitutes. This article reports the utilization of an immediate protective motion program to avoid the problems of postoperative stiffness and lack of knee extension. It can not be stated with certainly whether the same program can be applied to free grafts or to those obtained from other sites. However, the avoidance of these problems will significantly lessen the morbidity of intra-articular reconstruction. The utilization of a vascularized patellar tendon hopefully will add another dimension to ACL replacement.

Bone Transplantation↗

PubMedDate not supplied

Intra-articular cruciate reconstruction. II: Replacement with vascularized patellar tendon.

The patellar tendon offers a number of advantages (strength, location, bone-to-bone fixation, vascularity) as a tissue for intra-articular cruciate ligament reconstruction. The critical factor is to preserve the vascularity, thereby maintaining tendon viability and facilitating tissue remodeling. Laboratory studies on human cadaver knees were conducted to define the blood supply to the patella, and vascularity was assessed by blood flow studies in three animal species, including nonhuman primates. In humans, the patellar ligament receives blood anteriorly from the retinaculum and posteriorly from the fat pad, which is relatively smaller and less adherent than the fat pad in other animals. The medial third of the patellar tendon and its contiguous neurovascular pedicle were used in a vascularized patellar tendon reconstruction procedure. During a period of three years, reconstruction with the vascularized patellar tendon was performed in more than 100 patients. Although only 35 patients have been followed up for more than two years, the clinical results are encouraging. At present, however, the technique is not recommended for general use; the surgical procedure is demanding, and the ultimate clinical results may not warrant the extra effort required to perform the surgery as well as commit the patient to a long rehabilitation program.

Humans↗

PubMedDate not supplied

Clinical laxity tests and functional stability of the knee: biomechanical concepts.

Biomechanical studies show one or 2 ligaments provide the primary passive restraint for each plane of knee stability with the remaining ligaments having a secondary helping role. Correct interpretation of clinical laxity tests and surgical treatment of instability requires this subdivision. Functional stability of the knee is a primary treatment goal after ligament injury, but is too often short-term, relying on muscle control alone without the fine-tuning action of the ligamentous system. If there is abnormal laxity on the clinical examination, there is an increased risk for joint wear, cartilage deterioration and arthritis on a long-term basis.

Biomechanical Phenomena↗