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Femoral Tunnel Length in Anterior Cruciate Ligament Reconstruction Using an Accessory Medial Portal (SS-66)
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ABSTRACTS
fecting its maximum strength. Further studies will be necessary to determine its role in clinical practice. Long-Term Outcomes Following Allograft Reconstruction of the Anterior Cruciate Ligament (SS-65) LUTUL D. FARROW, M.D., PRESENTING AUTHOR ERIC A. LENEHAN, M.D. BRAD M ASKAM, B.S. WILLIAM G. GRANA, M.D. Introduction: Generally, good-excellent long-term results following anterior cruciate ligament (ACL) reconstruction exceed 90 percent. Recently some authors have reported higher rates of both reoperation and graft failure following allograft reconstruction of the ACL. We hypothesize that the rates of reoperation and revision surgery following allograft ACL reconstruction are not as high as that reported in the literature. The purpose of this study is to evaluate the long term results of a cohort of patients undergoing allograft ACL reconstruction at a single institution. Methods: We retrospectively reviewed all patients undergoing allograft ACL reconstruction performed by 2 senior surgeons over an eight year period (2000 – 2008). We recorded preoperative patient demographics and concomitant knee pathology. We also recorded the incidence of postoperative complications following ACL reconstruction (i.e. infection, repeat surgical procedures, graft rupture, etc.). Clinical evaluation was performed utilizing the International Knee Documentation Committee (IKDC) assessment and the Tegner Lysholm Knee scoring scale as well as the Tegner Lysholm activity scale. Results: A total of 99 patients with allograft and 24 patients with autograft ACL reconstruction were available for follow-up with an average length of follow up of 50 months. Seventeen percent (17/99) of patient’s required additional surgery following allograft ACL reconstruction (revision ACL reconstruction – 10/17, meniscus repair – 4/17, partial menisectomy – 6/17, infection – 3/17, and hardware removal – 2/17). The rate of revision surgery was much higher (30 percent) for patients under the age of twenty five (revision ACL reconstruction – 8/12, meniscus repair – 3/12, partial menisectomy – 5/12, infection – 1/12, and hardware removal – 1/12). Patients who did not have additional surgeries reported higher Tegner Lysholm (Avg 83) and IKDC (Avg 79) scores compared to those undergoing additional surgical procedures with Tegner and IKDC scores of 59 and 54, respectively. Fifty five percent of participants (55/99) were “happy” they had surgery. Only 51 percent of patients (51/99) reported that they would have the surgery again. Comparatively, the rate of revision
anterior cruciate ligament reconstruction following autograft ACL reconstruction was 4 percent. No patient under the age of 25 years required revision ACL reconstruction following autograft ACL reconstruction. Conclusion: The principal findings of this study demonstrate that the overall reoperation rate following allograft ACL reconstruction was much higher than that generally quoted following autograft ACL reconstruction. The rate of reoperation and revision ACL reconstruction for patients less than age 25 was thirty and twenty percent, respectively. Patients who required additional surgery had a lower subjective IKDC and Tegner Lysholm scores. While the overall rate of reoperation is acceptable in this patient population, the rate of reoperation in patients younger than 25 year of age is concerning and should be taken into account when considering allograft ACL reconstruction in patients younger than 25 years of age. Femoral Tunnel Length in Anterior Cruciate Ligament Reconstruction Using an Accessory Medial Portal (SS-66) MARC TOMPKINS, M.D., PRESENTING AUTHOR MATTHEW D. MILEWSKI, M.D. ERIC W. CARSON, M.D. STEPHEN F. BROCKMEIER, M.D. JOSEPH M. HART, PH.D. MARK D. MILLER, M.D. Introduction: Independent femoral tunnel drilling has been described in anterior cruciate ligament (ACL) reconstruction, however there is concern that tunnels will be too short. To counterbalance that and also provide better exposure to the notch, hyperflexion of the knee and the use of an accessory medial portal have been described. The purpose of this study was to evaluate tunnel length during independent femoral tunnel drilling using an accessory medial portal with the knee in maximal hyperflexion, and then correlate the tunnel length and flexion angle with anthropometric data. Methods: During a 9 month period, 83 consecutive patients undergoing primary ACL reconstruction by the three senior authors were included in the study. All patients underwent independent femoral tunnel drilling using an accessory medial portal with maximal knee hyperflexion. Tunnel length and maximal intra-operative knee flexion angles were measured. In addition, height, weight, and body mass index (BMI) were recorded in order to correlate with tunnel length and knee flexion angles. The size of the lateral femoral condyle (LFC), as measured on magnetic resonance imaging (MRI) or plain radiograph, was also correlated with tunnel length and knee flexion angles (available in 67 patients).
ABSTRACTS
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Results: The average tunnel length was 36.8 ⫹/⫺ 3.3 mm (range 26-45) with all but one tunnel greater than 30 mm. The average knee flexion angle was 134.3 ⫹/⫺ 5.0 degrees (range 122-147). The average BMI was 27.7 ⫹/⫺ 7.9 kg/m2 (range 17.7-63.3), calculated from average height 173.3 ⫹/⫺ 9.1 cm (range 150-195.6) and weight 83.3 ⫹/⫺ 24.8 kg (range 49.7-172.2). Average LFC width was 32.6 ⫹/⫺ 4.8 cm (range 26.1-60.3), and depth was 60.6 ⫹/⫺ 5.0 cm (range 48.1-73.3). Height (r⫽0.52, P⬍0.001) and weight (r⫽0.34, P⫽0.002), but not BMI, correlated positively with tunnel length. Width (r⫽0.33, P⫽0.006) and depth (r⫽0.34, P⫽0.005) of the LFC also correlated positively with tunnel length. Knee flexion angle was not correlated with tunnel length (r⫽0.08, P⫽0.45), or width (r⫽⫺0.06, P⫽0.62) and depth (r⫽⫺0.14, P⫽0.28) of the LFC. Knee flexion angle was negatively correlated with weight (r⫽⫺0.55, P⬍0.001) and BMI (r⫽⫺0.55, P⬍0.001). Conclusion: Using an accessory medial portal for independent femoral tunnel drilling with maximal knee hyperflexion in ACL reconstruction produced only one tunnel less than 30mm. This technique, therefore, consistently produces tunnels of adequate length. Tunnel lengths tend to be longer with increasing patient height, mass, and larger LFC dimensions. Maximum knee flexion angle achieved intraoperatively tends to be less for patients with increasing weight and BMI.
collateral ligament were measured for each guide pin as they exited out the lateral femoral cortex. We calculated the average tunnel lengths at various flexion angles and distances to the lateral structures for each guide pin in all of the specimens. Results: The average femoral tunnel length was found to be statistically longer with 120 degrees of knee flexion than at 70 degrees, 38.4 mm vs. 26 mm (p⫽0.0001). The average tunnel length was not statistically different between the 70 and 90 degree angles (26 ⫹/⫺ 4.18 mm and 32.4 ⫹/⫺ 9.24 mm respectively, p⫽0.08). No guide pin injured the common peroneal nerve. The mean distance to the common peroneal nerve was 50.2 mm ⫹/⫺ 15.53 at 70 degree knee flexion angle. This distance was significantly lower than the 120 degree flexion angle mean of 70 mm ⫹/⫺ 19.20 (p⫽0.01). Conclusion: Regardless of the type of guide pin and reamer system used in anatomic ACL reconstruction, knee flexion angle determines femoral tunnel length. Longer femoral tunnels were obtained with higher knee flexion angles, similar to previous studies using rigid guide pins. With flexible guide pins lower knee flexion angles provide tunnel lengths that may be sufficient for interference screw fixation but may not allow for sufficient length for suspensory or cortical fixation devices. Flexible guide pins do not put the common peroneal nerve at risk in any flexion angle.
Flexible Reamers in Anatomic ACL Reconstruction: Effect of Knee Flexion on Femoral Tunnel Length and Latrogenic Peroneal Nerve Injury (SS-67) EDWARD TANG, M.D., PRESENTING AUTHOR KUNAL KALRA, M.D. ABIOLA ATANDA, M.D. SAQIB HASAN, B.S. OMAR KHATIB, M.D. LAITH JAZRAWI, M.D.
The Effects of Trans-Tibial versus Anteromedial Portal Technique on the Stress Patterns around the Femoral Tunnel in Anatomical Single-Bundle ACL Reconstruction Using a Finite Element Analysis (SS-68) YOUNG-JIN SEO, M.D., PH.D., PRESENTING AUTHOR YON-SIK YOO, M.D., PH.D. SI YOUNG SONG, M.D. HAK JIN KIM, M.S. HEON YOUNG KIM, PH.D.
Introduction: The purpose of this study was to determine the effect of knee flexion angle on femoral tunnel length and distance of guide pin to critical lateral knee structures with the use of a flexible guide pin and reamer system from a standard anteromedial arthroscopic portal. Methods: We obtained 10 cadaveric knees, all of which had no evidence of prior knee surgery. The intact anterior cruciate ligament was debrided and the anatomic femoral footprint was identified. Flexible guide pins were inserted from a standard anteromedial portal in knee flexion angles of 70, 90 and 120 degrees using the same starting point. Tunnel lengths were determined for each of these guide pins at each angle. Distances from the common peroneal nerve and the origin of the fibular
Introduction: The femoral tunnel can be drilled through either far anteromedial(AM) portal or trans-tibial(TT) tunnel. Each method has its own advantage in terms of a proximity to ideal point, tunnel length and rotational stability. However, it remains unclear which method produces a better biomechanical outcome, especially in the stress distribution around femoral tunnel. We hypothesized that the different femoral tunnel direction would influence on the stress that occurs around the tunnels during the knee motion. The purpose of this study was to compare the differences in stress patterns around the femoral tunnel that was drilled through AM portal or trantibial tunnel in anatomical ACL reconstruction at different knee flexion angles.
ABSTRACTS
fecting its maximum strength. Further studies will be necessary to determine its role in clinical practice. Long-Term Outcomes Following Allograft Reconstruction of the Anterior Cruciate Ligament (SS-65) LUTUL D. FARROW, M.D., PRESENTING AUTHOR ERIC A. LENEHAN, M.D. BRAD M ASKAM, B.S. WILLIAM G. GRANA, M.D. Introduction: Generally, good-excellent long-term results following anterior cruciate ligament (ACL) reconstruction exceed 90 percent. Recently some authors have reported higher rates of both reoperation and graft failure following allograft reconstruction of the ACL. We hypothesize that the rates of reoperation and revision surgery following allograft ACL reconstruction are not as high as that reported in the literature. The purpose of this study is to evaluate the long term results of a cohort of patients undergoing allograft ACL reconstruction at a single institution. Methods: We retrospectively reviewed all patients undergoing allograft ACL reconstruction performed by 2 senior surgeons over an eight year period (2000 – 2008). We recorded preoperative patient demographics and concomitant knee pathology. We also recorded the incidence of postoperative complications following ACL reconstruction (i.e. infection, repeat surgical procedures, graft rupture, etc.). Clinical evaluation was performed utilizing the International Knee Documentation Committee (IKDC) assessment and the Tegner Lysholm Knee scoring scale as well as the Tegner Lysholm activity scale. Results: A total of 99 patients with allograft and 24 patients with autograft ACL reconstruction were available for follow-up with an average length of follow up of 50 months. Seventeen percent (17/99) of patient’s required additional surgery following allograft ACL reconstruction (revision ACL reconstruction – 10/17, meniscus repair – 4/17, partial menisectomy – 6/17, infection – 3/17, and hardware removal – 2/17). The rate of revision surgery was much higher (30 percent) for patients under the age of twenty five (revision ACL reconstruction – 8/12, meniscus repair – 3/12, partial menisectomy – 5/12, infection – 1/12, and hardware removal – 1/12). Patients who did not have additional surgeries reported higher Tegner Lysholm (Avg 83) and IKDC (Avg 79) scores compared to those undergoing additional surgical procedures with Tegner and IKDC scores of 59 and 54, respectively. Fifty five percent of participants (55/99) were “happy” they had surgery. Only 51 percent of patients (51/99) reported that they would have the surgery again. Comparatively, the rate of revision
anterior cruciate ligament reconstruction following autograft ACL reconstruction was 4 percent. No patient under the age of 25 years required revision ACL reconstruction following autograft ACL reconstruction. Conclusion: The principal findings of this study demonstrate that the overall reoperation rate following allograft ACL reconstruction was much higher than that generally quoted following autograft ACL reconstruction. The rate of reoperation and revision ACL reconstruction for patients less than age 25 was thirty and twenty percent, respectively. Patients who required additional surgery had a lower subjective IKDC and Tegner Lysholm scores. While the overall rate of reoperation is acceptable in this patient population, the rate of reoperation in patients younger than 25 year of age is concerning and should be taken into account when considering allograft ACL reconstruction in patients younger than 25 years of age. Femoral Tunnel Length in Anterior Cruciate Ligament Reconstruction Using an Accessory Medial Portal (SS-66) MARC TOMPKINS, M.D., PRESENTING AUTHOR MATTHEW D. MILEWSKI, M.D. ERIC W. CARSON, M.D. STEPHEN F. BROCKMEIER, M.D. JOSEPH M. HART, PH.D. MARK D. MILLER, M.D. Introduction: Independent femoral tunnel drilling has been described in anterior cruciate ligament (ACL) reconstruction, however there is concern that tunnels will be too short. To counterbalance that and also provide better exposure to the notch, hyperflexion of the knee and the use of an accessory medial portal have been described. The purpose of this study was to evaluate tunnel length during independent femoral tunnel drilling using an accessory medial portal with the knee in maximal hyperflexion, and then correlate the tunnel length and flexion angle with anthropometric data. Methods: During a 9 month period, 83 consecutive patients undergoing primary ACL reconstruction by the three senior authors were included in the study. All patients underwent independent femoral tunnel drilling using an accessory medial portal with maximal knee hyperflexion. Tunnel length and maximal intra-operative knee flexion angles were measured. In addition, height, weight, and body mass index (BMI) were recorded in order to correlate with tunnel length and knee flexion angles. The size of the lateral femoral condyle (LFC), as measured on magnetic resonance imaging (MRI) or plain radiograph, was also correlated with tunnel length and knee flexion angles (available in 67 patients).
ABSTRACTS
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Results: The average tunnel length was 36.8 ⫹/⫺ 3.3 mm (range 26-45) with all but one tunnel greater than 30 mm. The average knee flexion angle was 134.3 ⫹/⫺ 5.0 degrees (range 122-147). The average BMI was 27.7 ⫹/⫺ 7.9 kg/m2 (range 17.7-63.3), calculated from average height 173.3 ⫹/⫺ 9.1 cm (range 150-195.6) and weight 83.3 ⫹/⫺ 24.8 kg (range 49.7-172.2). Average LFC width was 32.6 ⫹/⫺ 4.8 cm (range 26.1-60.3), and depth was 60.6 ⫹/⫺ 5.0 cm (range 48.1-73.3). Height (r⫽0.52, P⬍0.001) and weight (r⫽0.34, P⫽0.002), but not BMI, correlated positively with tunnel length. Width (r⫽0.33, P⫽0.006) and depth (r⫽0.34, P⫽0.005) of the LFC also correlated positively with tunnel length. Knee flexion angle was not correlated with tunnel length (r⫽0.08, P⫽0.45), or width (r⫽⫺0.06, P⫽0.62) and depth (r⫽⫺0.14, P⫽0.28) of the LFC. Knee flexion angle was negatively correlated with weight (r⫽⫺0.55, P⬍0.001) and BMI (r⫽⫺0.55, P⬍0.001). Conclusion: Using an accessory medial portal for independent femoral tunnel drilling with maximal knee hyperflexion in ACL reconstruction produced only one tunnel less than 30mm. This technique, therefore, consistently produces tunnels of adequate length. Tunnel lengths tend to be longer with increasing patient height, mass, and larger LFC dimensions. Maximum knee flexion angle achieved intraoperatively tends to be less for patients with increasing weight and BMI.
collateral ligament were measured for each guide pin as they exited out the lateral femoral cortex. We calculated the average tunnel lengths at various flexion angles and distances to the lateral structures for each guide pin in all of the specimens. Results: The average femoral tunnel length was found to be statistically longer with 120 degrees of knee flexion than at 70 degrees, 38.4 mm vs. 26 mm (p⫽0.0001). The average tunnel length was not statistically different between the 70 and 90 degree angles (26 ⫹/⫺ 4.18 mm and 32.4 ⫹/⫺ 9.24 mm respectively, p⫽0.08). No guide pin injured the common peroneal nerve. The mean distance to the common peroneal nerve was 50.2 mm ⫹/⫺ 15.53 at 70 degree knee flexion angle. This distance was significantly lower than the 120 degree flexion angle mean of 70 mm ⫹/⫺ 19.20 (p⫽0.01). Conclusion: Regardless of the type of guide pin and reamer system used in anatomic ACL reconstruction, knee flexion angle determines femoral tunnel length. Longer femoral tunnels were obtained with higher knee flexion angles, similar to previous studies using rigid guide pins. With flexible guide pins lower knee flexion angles provide tunnel lengths that may be sufficient for interference screw fixation but may not allow for sufficient length for suspensory or cortical fixation devices. Flexible guide pins do not put the common peroneal nerve at risk in any flexion angle.
Flexible Reamers in Anatomic ACL Reconstruction: Effect of Knee Flexion on Femoral Tunnel Length and Latrogenic Peroneal Nerve Injury (SS-67) EDWARD TANG, M.D., PRESENTING AUTHOR KUNAL KALRA, M.D. ABIOLA ATANDA, M.D. SAQIB HASAN, B.S. OMAR KHATIB, M.D. LAITH JAZRAWI, M.D.
The Effects of Trans-Tibial versus Anteromedial Portal Technique on the Stress Patterns around the Femoral Tunnel in Anatomical Single-Bundle ACL Reconstruction Using a Finite Element Analysis (SS-68) YOUNG-JIN SEO, M.D., PH.D., PRESENTING AUTHOR YON-SIK YOO, M.D., PH.D. SI YOUNG SONG, M.D. HAK JIN KIM, M.S. HEON YOUNG KIM, PH.D.
Introduction: The purpose of this study was to determine the effect of knee flexion angle on femoral tunnel length and distance of guide pin to critical lateral knee structures with the use of a flexible guide pin and reamer system from a standard anteromedial arthroscopic portal. Methods: We obtained 10 cadaveric knees, all of which had no evidence of prior knee surgery. The intact anterior cruciate ligament was debrided and the anatomic femoral footprint was identified. Flexible guide pins were inserted from a standard anteromedial portal in knee flexion angles of 70, 90 and 120 degrees using the same starting point. Tunnel lengths were determined for each of these guide pins at each angle. Distances from the common peroneal nerve and the origin of the fibular
Introduction: The femoral tunnel can be drilled through either far anteromedial(AM) portal or trans-tibial(TT) tunnel. Each method has its own advantage in terms of a proximity to ideal point, tunnel length and rotational stability. However, it remains unclear which method produces a better biomechanical outcome, especially in the stress distribution around femoral tunnel. We hypothesized that the different femoral tunnel direction would influence on the stress that occurs around the tunnels during the knee motion. The purpose of this study was to compare the differences in stress patterns around the femoral tunnel that was drilled through AM portal or trantibial tunnel in anatomical ACL reconstruction at different knee flexion angles.