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Effect of Notchplasty in Anterior Cruciate Ligament Reconstruction: A Biomechanical Study in Porcine Knees (SS-74)
ABSTRACTS should also not be considered a reliable means of estimating patellar tendon length prior to surgery. Effect of Notchplasty in Anterior Cruciate Ligament Reconstruction: A Biomechanical Study in Porcine Knees (SS-74) KENAN KEKLIKCI, M.D., PRESENTING AUTHOR CAN YAPICI, M.D. DONGHWI KIM, M.D. MONICA A. LINDE-ROSEN, A.D.N., B.S.M.E. PATRICK SMOLINSKI, PH.D. FREDDIE H FU, M.D., D.SC. Introduction: In anterior cruciate ligament (ACL) reconstruction, notchplasty is frequently performed by many surgeons. It is not well understood how notchplasty may effect tunnel placement and knee kinematics. The purpose of this study is to investigate the biomechanical effects of notchplasty on the ACL reconstructed knee. The hypothesis is that notchplasty will affect knee biomechanics in ACL reconstructed knee. Methods: Twelve (n⫽12) mature, fresh frozen porcine knees were tested using a robotic/universal force/moment sensor (UFS) testing system. All ACL reconstructions were performed via arthroscopy using a threeportal technique. Four knee states were compared: 1) intact ACL 2) ACL-Deficient 3) Anatomic single bundle (SB) ACL reconstruction and 4) Anatomic SB ACL reconstruction with a 5 mm notchplasty. The same tunnel was used for states 3 and 4. The graft was fixed at 60° of knee flexion and tensioned at 80-N with an Endobutton on the femur and a post-screw on the tibia. All knees were subjected to the following loading conditions: an 89-N anterior tibial load to test anterior tibial translation (ATT) and a 4 N-m internal rotation (IR) and external rotation (ER) tibial torque. The knee kinematics and in situ force obtained from the different knee conditions were compared. The data (mean ⫾ standard deviation), was analyzed (Prism GraphPad Version 5.0a) using a two-tailed Paired t-test with the level of significance set at P ⬍ 0.05. Results: There was no significant differences between pre and post notchplasty in ER at 30° (full extension in porcine knee) and 60° of flexion (p⬎0.05). However, a significant difference was found between pre and post notchplasty in ATT at 30° and 60° of flexion (p ⬍ 0.05). In-situ force in anatomic single bundle reconstruction with notchplasty was significant lower than intact and anatomic reconstructed ACL pre-notchplasty at 30 °, 60° and 90° flexion of the knee (p ⬍ 0.05). In response to an IR tibial torque, there were not significant differences between pre and post notchplasty at 30° of knee flexion (p⬎0.05). However, a significant difference was found
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between pre and post notchplasty in IR at 60° (p⬍0.05) of knee flexion. Conclusion: The results of this study showed that notchplasty did not result in an increase in ER at 30° and 60° degrees of knee flexion and IR at 30° degree of knee flexion; but lead to an increase in ATT at 30° and 60° degrees of knee flexion and in IR at 60° degree of knee flexion. Notchplasty had more effect on anterior stability than rotational stability. This change in knee kinematics could be detrimental to a bone healing and graft ligamentization and could lead to graft failure. Long-Term Outcomes of Medial Reefing for Recurrent Patellar Instability (SS-75) MADHAV R. BODDULA, M.D., M.P.H., PRESENTING AUTHOR GREGORY ADAMSON, M.D. MARILYN PINK, P.T., PH.D. Introduction: Patellofemoral instability is a common condition in young patients. For recurrent patellofemoral instability, there is no consensus for the optimal surgical technique. Despite many different surgical procedures discussed in the literature, there are few studies on longterm outcomes. Methods: From November 1993 to November 2001, arthroscopically assisted medial reefing procedures were performed. All patients had recurrent patellar instability with normal bony anatomy, and had failed 6 months of conservative treatment. Patients underwent a history, physical examination, and a radiographic evaluation. Successful mid-term outcomes (61 months) for this original group of patients (24 patients, 25 knees) were published in 2007. Eighty percent of this cohort (19 patients, 20 knees) were available at long-term follow up (142 months, 11.8 years). Outcomes evaluated included Lysholm and Tegner scores, subjective data, and physical exam and radiographic findings. Comparative statistics were used for preoperative, mid-term, and long-term results. Results: All patients were satisfied with the results of their surgery and would have the same procedure performed again. There was one recurrent dislocation and one recurrent subluxation. All subjective symptom scores showed significant improvement. Pain decreased on the VAS from 6.4 to 1.9, instability decreased from 7.9 to 0.6, and swelling decreased from 5.1 to 0.9 (P ⬍ 0.001). Lysholm knee scores improved significantly from 53.2 to 86.2 (P ⬍ 0.001). Tegner scores improved from 3.2 to 4.7 (P ⬍ 0.001). Improvement was demonstrated in physical exam findings including a decrease in patellar apprehension from 100% to 15% (P ⬍ 0.001), and a decrease in total arc of patellar glide from 4.9 to 2.4
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between pre and post notchplasty in IR at 60° (p⬍0.05) of knee flexion. Conclusion: The results of this study showed that notchplasty did not result in an increase in ER at 30° and 60° degrees of knee flexion and IR at 30° degree of knee flexion; but lead to an increase in ATT at 30° and 60° degrees of knee flexion and in IR at 60° degree of knee flexion. Notchplasty had more effect on anterior stability than rotational stability. This change in knee kinematics could be detrimental to a bone healing and graft ligamentization and could lead to graft failure. Long-Term Outcomes of Medial Reefing for Recurrent Patellar Instability (SS-75) MADHAV R. BODDULA, M.D., M.P.H., PRESENTING AUTHOR GREGORY ADAMSON, M.D. MARILYN PINK, P.T., PH.D. Introduction: Patellofemoral instability is a common condition in young patients. For recurrent patellofemoral instability, there is no consensus for the optimal surgical technique. Despite many different surgical procedures discussed in the literature, there are few studies on longterm outcomes. Methods: From November 1993 to November 2001, arthroscopically assisted medial reefing procedures were performed. All patients had recurrent patellar instability with normal bony anatomy, and had failed 6 months of conservative treatment. Patients underwent a history, physical examination, and a radiographic evaluation. Successful mid-term outcomes (61 months) for this original group of patients (24 patients, 25 knees) were published in 2007. Eighty percent of this cohort (19 patients, 20 knees) were available at long-term follow up (142 months, 11.8 years). Outcomes evaluated included Lysholm and Tegner scores, subjective data, and physical exam and radiographic findings. Comparative statistics were used for preoperative, mid-term, and long-term results. Results: All patients were satisfied with the results of their surgery and would have the same procedure performed again. There was one recurrent dislocation and one recurrent subluxation. All subjective symptom scores showed significant improvement. Pain decreased on the VAS from 6.4 to 1.9, instability decreased from 7.9 to 0.6, and swelling decreased from 5.1 to 0.9 (P ⬍ 0.001). Lysholm knee scores improved significantly from 53.2 to 86.2 (P ⬍ 0.001). Tegner scores improved from 3.2 to 4.7 (P ⬍ 0.001). Improvement was demonstrated in physical exam findings including a decrease in patellar apprehension from 100% to 15% (P ⬍ 0.001), and a decrease in total arc of patellar glide from 4.9 to 2.4