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Biologic composite fixation of porous-coated segmental bone defect replacement prostheses in limb salvage surgery
996
Abstracts-International
Society
of Biomechanics
XII
Congress
THE DEVELOPMENT OF A SIZE AND SHAPE MATCHING INDEX FOR OSTEOCHONDRAL ALLOGRAFTS E.Y.S. Chao, M. L. Samson, K. N. An, M. G.Rock, R. Robb Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905, U.S.A. We investigated the three-dimensional geometry of the distal hemicondylar allograft reconstruction. The CT scan data of ten graphic reconstruction and three-dimensional projections utilizing techniques to determine the radii of each condyle. Three-dimensional several normal subjects was used to allow hemicondylar resection cadaveric femurs. Using the rigid body spring model technique, in contact regions was calculated assuming a one-legged stance. geometric parameters for pressure distribution, kinematic analysis
19X9
femur and simulated distal femurs allowed least square fit reconstruction of and reconstruction of the pressure distribution Defining the most relevant is necessary.
BIOLOGIC COMPOSITE FIXATION OF POROUS-COATED SEGMENTAL BONE DEFECT REPLACEMENT PROSTHESES IN LIMB SALVAGE SURGERY Edmund Y.S. Chao and Franklin H. Sim Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905 U.S.A Fixation of segmental defect replacement (SDR) prostheses has been difficult. A new concept was developed which uses bone cement for initial stabilization and bone grafts applied over the porous segment to achieve extracortical bone bridging and ingrowth Experiments have validated this concept. Key factors affect-ing the outcome fixation. include bone graft amount and placement, initial implant stability, and adjuvant therapy. SDR prostheses in 23 patients (>24-mo. follow-up) were reviewed. Bone bridging occurred in 69% of effective areas around the prostheses. Seventy percent of patients were rated excellent or good, 10% fair, and 20% poor. Poor results were associated with tumor recurrence, infection, and implant failure. With improvements in implant design, biologic composite fixation of SDR prostheses will play a key role in limb salvage surgery.
MEASUREMENT OF NECK RANGE AND PATTERN OF MOVEMENT Sarah Korinek, and Thomas Cahalan Edmund Y.S. Chao, Shinji Tanaka, Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905, U.S.A. Accurate measurement of neck motion has been difficult due to its compound movement A method developed uses the 3Space’ Isotrak”l System and lack of bony reference landmarks. which utilizes low-frequency magnetic field coupling theory to determine location and orientation of a “sensor” in reference to a ‘source.II The sensor is placed on a subject’s forehead and the source is fastened on the trunk which is immobilized to a chair. The Eulerian angles are used to define gross motion of the head relative to the trunk in terms Thirty normal subjects of flexion-extension, right and left lateral bending, and rotation. were evaluated. Women had larger range of motion, and age had a significant effect on neck This method was movement. Coupled motion existed between lateral bending and rotation. found to be repeatable and reliable for clinical application.
A BIOMECHANICAL RATIONALE FOR THE PREFERRED STYLE OF RUNNING Arthur E. Chapman and Robert M. Lonergan, Simon Fraser University, Burnaby, British Columbia, Canada, V5A lS6. One male 5km runner (mass = 62.5kg, stature = 1.74m) of international calibre ran across a force platform while being filmed. Five runs were performed with his preferred style (PS) and 2 runs with each of 4 non-preferred (NP) styles at each of 3 speeds. The question of interest was whether minimization of mechanical impulse (MI) is a criterion for choice of preferred running style. Total MI was obtained by summing flexor and extensor MI’s over ankle, knee and hip joints. While total MI’s of all NP styles were greater than the mean MI of PS at each speed, some MI’s were not significantly different from those of PS. Yet those NP styles could not have been used to run any substantial distance. It is concluded that total MI is not a single criterion by which a person chooses a running style. At least one individual (flexor or extensor at the 3 joints) MI in each NP style was significantly greater than the corresponding PS MI. In some cases individual MI’s were over 6 times greater. It is concluded that a criterion of choice of the preferred style is minimization of individual muscle-group Ml’s, The subjective impression of the athlete was that specific muscle soreness was associated with the NP styles. A decrease in a specific MI may offset an increase elsewhere, such that the total MI may be similar in the PS and NP styles. However the NP style can not be tolerated because of the large demands made upon one or two specific muscle-groups.
Abstracts-International
Society
of Biomechanics
XII
Congress
THE DEVELOPMENT OF A SIZE AND SHAPE MATCHING INDEX FOR OSTEOCHONDRAL ALLOGRAFTS E.Y.S. Chao, M. L. Samson, K. N. An, M. G.Rock, R. Robb Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905, U.S.A. We investigated the three-dimensional geometry of the distal hemicondylar allograft reconstruction. The CT scan data of ten graphic reconstruction and three-dimensional projections utilizing techniques to determine the radii of each condyle. Three-dimensional several normal subjects was used to allow hemicondylar resection cadaveric femurs. Using the rigid body spring model technique, in contact regions was calculated assuming a one-legged stance. geometric parameters for pressure distribution, kinematic analysis
19X9
femur and simulated distal femurs allowed least square fit reconstruction of and reconstruction of the pressure distribution Defining the most relevant is necessary.
BIOLOGIC COMPOSITE FIXATION OF POROUS-COATED SEGMENTAL BONE DEFECT REPLACEMENT PROSTHESES IN LIMB SALVAGE SURGERY Edmund Y.S. Chao and Franklin H. Sim Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905 U.S.A Fixation of segmental defect replacement (SDR) prostheses has been difficult. A new concept was developed which uses bone cement for initial stabilization and bone grafts applied over the porous segment to achieve extracortical bone bridging and ingrowth Experiments have validated this concept. Key factors affect-ing the outcome fixation. include bone graft amount and placement, initial implant stability, and adjuvant therapy. SDR prostheses in 23 patients (>24-mo. follow-up) were reviewed. Bone bridging occurred in 69% of effective areas around the prostheses. Seventy percent of patients were rated excellent or good, 10% fair, and 20% poor. Poor results were associated with tumor recurrence, infection, and implant failure. With improvements in implant design, biologic composite fixation of SDR prostheses will play a key role in limb salvage surgery.
MEASUREMENT OF NECK RANGE AND PATTERN OF MOVEMENT Sarah Korinek, and Thomas Cahalan Edmund Y.S. Chao, Shinji Tanaka, Biomechanics Laboratory, Department of Orthopedics Mayo Clinic/Mayo Foundation, Rochester, MN 55905, U.S.A. Accurate measurement of neck motion has been difficult due to its compound movement A method developed uses the 3Space’ Isotrak”l System and lack of bony reference landmarks. which utilizes low-frequency magnetic field coupling theory to determine location and orientation of a “sensor” in reference to a ‘source.II The sensor is placed on a subject’s forehead and the source is fastened on the trunk which is immobilized to a chair. The Eulerian angles are used to define gross motion of the head relative to the trunk in terms Thirty normal subjects of flexion-extension, right and left lateral bending, and rotation. were evaluated. Women had larger range of motion, and age had a significant effect on neck This method was movement. Coupled motion existed between lateral bending and rotation. found to be repeatable and reliable for clinical application.
A BIOMECHANICAL RATIONALE FOR THE PREFERRED STYLE OF RUNNING Arthur E. Chapman and Robert M. Lonergan, Simon Fraser University, Burnaby, British Columbia, Canada, V5A lS6. One male 5km runner (mass = 62.5kg, stature = 1.74m) of international calibre ran across a force platform while being filmed. Five runs were performed with his preferred style (PS) and 2 runs with each of 4 non-preferred (NP) styles at each of 3 speeds. The question of interest was whether minimization of mechanical impulse (MI) is a criterion for choice of preferred running style. Total MI was obtained by summing flexor and extensor MI’s over ankle, knee and hip joints. While total MI’s of all NP styles were greater than the mean MI of PS at each speed, some MI’s were not significantly different from those of PS. Yet those NP styles could not have been used to run any substantial distance. It is concluded that total MI is not a single criterion by which a person chooses a running style. At least one individual (flexor or extensor at the 3 joints) MI in each NP style was significantly greater than the corresponding PS MI. In some cases individual MI’s were over 6 times greater. It is concluded that a criterion of choice of the preferred style is minimization of individual muscle-group Ml’s, The subjective impression of the athlete was that specific muscle soreness was associated with the NP styles. A decrease in a specific MI may offset an increase elsewhere, such that the total MI may be similar in the PS and NP styles. However the NP style can not be tolerated because of the large demands made upon one or two specific muscle-groups.