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Biomedical subjects

Paul E Caldwell

Publications and source records attributed to Paul E Caldwell.

2 recordsLinked to original sources

Indications for allografts.

Allografts continue to be popular in orthopaedic reconstruction procedures of the knee. Approximately 1 million musculoskeletal allografts were distributed in the United States in 2004 alone. Ligament allografts, osteochondral allografts, and meniscal transplants have all demonstrated success in knee reconstructions. The advantages of allograft tissue include the lack of donor site morbidity, shorter operative times, ease of sizing, and a lack of clinically significant immunologic reactions. These advantages should be weighed against the risk for disease transmission, increased cost, and increased time of graft incorporation. Throughout the consent process, comprehensive patient education is imperative to assist in this important decision.

Arthroplasty↗

Dynamic confirmation of fixation techniques of the tibial tubercle osteotomy.

The tibial tubercle osteotomy is gaining popularity for revision total knee arthroplasty; however, the potential for tubercle displacement has been a concern. This study compared the mechanical behavior of the tibial tubercle osteotomy after screw and cerclage wire fixation. Tibial tubercle osteotomy was done on 40 tibias from cadavers with equal numbers fixed by either screws or wires. Specimens were loaded cyclically to simulate straight leg raises and then loaded to failure with the patellar tendon oriented 0 degrees or 25 degrees from the tibial axis. Tibial tubercle osteotomy cyclic displacement was greater for wire constructs at 25 degrees than all other constructs. Failure loads were greater for screw constructs at 25 degrees than both wire constructs. Screw constructs failed at 1429 +/- 348 N (0 degrees) and at 1925 +/- 982 N (25 degrees). Wire constructs failed at 1072 +/- 260 N (0 degrees) and at 893 +/- 293 N (25 degrees). Bone mineral density correlated positively with failure loads. Straight leg raise (400 N) and knee extension (250 N) against gravity during rehabilitation should be feasible with either screw or wire fixation after tibial tubercle osteotomy. Special care should be taken for the large patient and patients with decreased bone density.

Biomechanical Phenomena↗