- Email: [email protected]
A-0040 3.1 Heterogeneous muscle and tendon length adaptations to acute tendon transfer
12
THE JOURNAL OF HAND SURGERY VOL. 32E SUPPLEMENT 1
A-0040 3.1 HETEROGENEOUS MUSCLE AND TENDON LENGTH ADAPTATIONS TO ACUTE TENDON TRANSFER
A-0064 3.2 INTRAOPERATIVE LASER DIFFRACTION YIELDS ACCURATE WHOLE MUSCLE SARCOMERE LENGTH MEASUREMENTS DURING TENDON TRANSFER SURGERY
M. Takahashi, J. Fride´n and R. L. Lieber From the Departments of Orthopaedic Surgery, Bioengineering, and Radiology, University of California San Diego, USA and the Department of Hand Surgery, Go¨teborg University, Sweden
M. Takahashi, J. Fride´n and R. L. Lieber From the Departments of Orthopaedic Surgery, Bioengineering, and Radiology, University of California San Diego, USA and the Department of Hand Surgery, Go¨teborg University, Sweden
Background: Intraoperatively, it is often necessary to ‘‘tension’’ transferred muscles to optimise function. Although it is assumed that muscle-tendon units adapt appropriately to ‘‘tensioning’’, there is little data to support this theory. Aim: To characterise the time-course of muscle and tendon adaptation to tensioning during tendon transfer surgery. Methods: The distal tendon of the rabbit EDII muscle was transferred under tension to the extensor retinaculum. Animals were sacrificed at 1 day (n ¼ 7), 7 days (n ¼ 7), 14 days (n ¼ 8), and 28 days (n ¼ 8). Muscle length, sarcomere length, sarcomere number, and tendon length were measured at each time. T-tests and ANOVA compared transferred and contralateral control muscles over time. Data reported as mean7SE; significance defined as Po0.05. Results: Intraoperatively, muscles were purposefully ‘‘tensioned’’ to 3.7 mm compared to the native 2.7670.02 mm. Sarcomere length decreased significantly at 1 day (3.2770.09 mm) and day 7 (2.5670.04 mm) and continued to decrease at days 14 (2.4470.03 mm) and 28 (2.2170.03 mm). Sarcomere number did not increase significantly until day 7 (+10507172), and then decreased from days 7 to 14 (+664791) to day 28 (+4007110). Tendon length increased slightly on day 7 (+1.471.0) and day 14 (+1.070.2 mm) and significantly on day 28 (+2.870.5 mm). Discussion/Conclusions: The most important finding of this study is that muscle and tendons both adapt to ‘‘tensioning’’ but with different time courses. Sarcomere length decreases at day 7 result primarily from sarcomere number addition while sarcomere length decreases at day 28 result primarily from tendon elongation. This data provides the first insight into both muscle and tendon length adaptations in stretched muscle-tendon units. The basis for the delayed tendon response relative to muscle is not known.
Background: Laser diffraction is the only available method to set muscle tendon units to a specific sarcomere length intraoperatively. However, this technique is typically used on a single point within a much larger muscle, and therefore, its ability to characterise whole muscle is unknown. Aim: To compare single-site intraoperative sarcomere length values with sarcomere lengths measured from systematic whole muscle sampling. Methods: The tendon of the second toe extensor muscle in the rabbit (n ¼ 20) was transposed to the crural extensor retinaculum at sarcomere lengths ranging from 2.5 to 4.0 mm. Intraoperative single-site sarcomere length was then measured using a laser diffraction device. Animals were then euthanised, muscles extracted, and whole muscle sarcomere length measurements were then determined in the proximal, middle and distal regions. Linear regression analysis and intraclass correlation coefficients were used to validate single intraoperative sarcomere lengths relative whole muscle sarcomere lengths. Results: Single intraoperative sarcomere lengths correlated strongly with average whole muscle sarcomere length (Po0.0001, r2 ¼ 0.794). This agreement was substantiated by an intraclass correlation coefficient of 0.805, though there was a systematic tendency to overestimate intraoperative sarcomere length. Intraoperative sarcomere length also matched well with all regions sampled, indicating there was no tendency for intraoperative sarcomere length to better represent one region of the muscle compared to another. Discussion/Conclusions: These results demonstrate that intraoperative sarcomere lengths accurately represent the entire muscle. The relatively small sarcomere length variations validate the use of intraoperative sarcomere length measurement during tendon transfer in which the entire muscle is not available for the measurement due to the limited exposure.
10.1016/j.jhse.2007.02.087
10.1016/j.jhse.2007.02.088
THE JOURNAL OF HAND SURGERY VOL. 32E SUPPLEMENT 1
A-0040 3.1 HETEROGENEOUS MUSCLE AND TENDON LENGTH ADAPTATIONS TO ACUTE TENDON TRANSFER
A-0064 3.2 INTRAOPERATIVE LASER DIFFRACTION YIELDS ACCURATE WHOLE MUSCLE SARCOMERE LENGTH MEASUREMENTS DURING TENDON TRANSFER SURGERY
M. Takahashi, J. Fride´n and R. L. Lieber From the Departments of Orthopaedic Surgery, Bioengineering, and Radiology, University of California San Diego, USA and the Department of Hand Surgery, Go¨teborg University, Sweden
M. Takahashi, J. Fride´n and R. L. Lieber From the Departments of Orthopaedic Surgery, Bioengineering, and Radiology, University of California San Diego, USA and the Department of Hand Surgery, Go¨teborg University, Sweden
Background: Intraoperatively, it is often necessary to ‘‘tension’’ transferred muscles to optimise function. Although it is assumed that muscle-tendon units adapt appropriately to ‘‘tensioning’’, there is little data to support this theory. Aim: To characterise the time-course of muscle and tendon adaptation to tensioning during tendon transfer surgery. Methods: The distal tendon of the rabbit EDII muscle was transferred under tension to the extensor retinaculum. Animals were sacrificed at 1 day (n ¼ 7), 7 days (n ¼ 7), 14 days (n ¼ 8), and 28 days (n ¼ 8). Muscle length, sarcomere length, sarcomere number, and tendon length were measured at each time. T-tests and ANOVA compared transferred and contralateral control muscles over time. Data reported as mean7SE; significance defined as Po0.05. Results: Intraoperatively, muscles were purposefully ‘‘tensioned’’ to 3.7 mm compared to the native 2.7670.02 mm. Sarcomere length decreased significantly at 1 day (3.2770.09 mm) and day 7 (2.5670.04 mm) and continued to decrease at days 14 (2.4470.03 mm) and 28 (2.2170.03 mm). Sarcomere number did not increase significantly until day 7 (+10507172), and then decreased from days 7 to 14 (+664791) to day 28 (+4007110). Tendon length increased slightly on day 7 (+1.471.0) and day 14 (+1.070.2 mm) and significantly on day 28 (+2.870.5 mm). Discussion/Conclusions: The most important finding of this study is that muscle and tendons both adapt to ‘‘tensioning’’ but with different time courses. Sarcomere length decreases at day 7 result primarily from sarcomere number addition while sarcomere length decreases at day 28 result primarily from tendon elongation. This data provides the first insight into both muscle and tendon length adaptations in stretched muscle-tendon units. The basis for the delayed tendon response relative to muscle is not known.
Background: Laser diffraction is the only available method to set muscle tendon units to a specific sarcomere length intraoperatively. However, this technique is typically used on a single point within a much larger muscle, and therefore, its ability to characterise whole muscle is unknown. Aim: To compare single-site intraoperative sarcomere length values with sarcomere lengths measured from systematic whole muscle sampling. Methods: The tendon of the second toe extensor muscle in the rabbit (n ¼ 20) was transposed to the crural extensor retinaculum at sarcomere lengths ranging from 2.5 to 4.0 mm. Intraoperative single-site sarcomere length was then measured using a laser diffraction device. Animals were then euthanised, muscles extracted, and whole muscle sarcomere length measurements were then determined in the proximal, middle and distal regions. Linear regression analysis and intraclass correlation coefficients were used to validate single intraoperative sarcomere lengths relative whole muscle sarcomere lengths. Results: Single intraoperative sarcomere lengths correlated strongly with average whole muscle sarcomere length (Po0.0001, r2 ¼ 0.794). This agreement was substantiated by an intraclass correlation coefficient of 0.805, though there was a systematic tendency to overestimate intraoperative sarcomere length. Intraoperative sarcomere length also matched well with all regions sampled, indicating there was no tendency for intraoperative sarcomere length to better represent one region of the muscle compared to another. Discussion/Conclusions: These results demonstrate that intraoperative sarcomere lengths accurately represent the entire muscle. The relatively small sarcomere length variations validate the use of intraoperative sarcomere length measurement during tendon transfer in which the entire muscle is not available for the measurement due to the limited exposure.
10.1016/j.jhse.2007.02.087
10.1016/j.jhse.2007.02.088