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Paper 155: Measurement of Anteroposterior and Rotational Stability of Knee using Navigation System
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was obtained with C-arm of Arcadis Orbic (Siemens, Germany). The image was transferred to a navigation system (StealthStation navigation system, Medtronic, Louisville, CO) and reconstructed into a 3D image of the distal femur. During placement of guide wires for femoral tunnels through an accessory medial portal, a femoral guide with a tracker feed backed surgeons the direction of the guide wire on the 3D femur bone surface image with real time fashion. The femoral guide was placed at the center of the footprint with help of visual guidance of the navigation as well as an arthroscopic view. Then, flexion angle of the knee was adjusted to prevent posterior blowout on the computer screen during insertion of the guide wire. The length of the femoral tunnel could also be estimated before over drilling the guide wire. This technology assists surgeons to place two femoral tunnels precisely without any complication during anatomic double-bundle ACL reconstruction.
Paper 154: Navigation Evaluation of Pivot Shift During Anatomical Double-bundle ACL Reconstruction YASUYUKI ISHIBASHI, MD, JAPAN, PRESENTING AUTHOR EIICHI TSUDA, MD, JAPAN AKIRA FUKUDA, MD, JAPAN YUJI YAMAMOTO, MD, JAPAN, HAREHIKO TSUKADA, MD, JAPAN SATOSHI TOH, MD, JAPAN ABSTRACT Objective: Anterolateral rotatory instability (pivot shift) causes disability in anterior cruciate ligament (ACL) deficient knees, and sometimes even in ACL reconstructed knees. Therefore the interest that double-bundle ACL reconstruction (DB-ACLR) that reproduces anteromedial (AM) and posterolateral (PL) bundles of the ACL has risen. However, it is still unknown which of the AM and PL bundle is more important to prevent pivot shift phenomenon. The purpose of this study was to assess which bundle prevents pivot shift during DB-ACLR using a navigation system. Materials and Methods: Eighty patients, who received DB-ACLR using a navigation, were included in this study. Their mean age was 21.3 years. During DBACLR, pivot shift tests were performed four times at before reconstruction, and at after only PLB fixation, only AMB fixation, and both PLB and AMB fixation. Tibial internal rotation and anterior translation were measured at each phase by the additional functions of the navigation. The navigation system used in this study was OrthoPilot ACL ver 2.0 (B/Braun Aesculap, Germany), which was image-free navigation.
Results: Before ACL reconstruction, tibial internal rotation and anterior translation were 22.9⫾7.6° and 5.4⫾2.5mm. After PLB fixation, internal rotation and anterior translation significantly decreased to 19.5⫾7.5° and 2.2⫾0.9mm. After AMB fixation, they both decreased to 21.6⫾6.7° and 2.4⫾0.9mm. After PLB and AMB fixation (DB-ACLR), these data were improved to 19.0⫾7.3° and 2.0⫾0.7mm. Conclusions: Although it is well known that the ACL is a primary restraint of the knee under anterior tibial load, the role of the ACL in resisting internal tibial torque and the pivot shift test is controversial. To our knowledge, this is the first study which assess the functions of AM and PL bundle of ACL to prevent pivot shift phenomenon in vivo. Our data indicate that both AMB and PLB play a role in restraining not only anterior translation but also internal rotation during pivot shift test, and DBACLR improves knee stability. These findings are also consistent with previous in-vitro biomechanical studies, which measured in-situ forces of each bundle of the ACL. Paper 155: Measurement of Anteroposterior and Rotational Stability of Knee using Navigation System EUN KYOO SONG, MD, KOREA, PRESENTING AUTHOR TAEK RIM YOON, MD, SOUTH KOREA YOUNG JIN KIM, MD, SOUTH KOREA CHANG ICH HUR, MD, SOUTH KOREA KYUNG SOON PARK, MD, SOUTH KOREA DAM SEON LEE, MD, SOUTH KOREA JONG KEUN SEON, MD, SOUTH KOREA SANG JIN PARK, MD, SOUTH KOREA ABSTRACT Purpose: The aim of study was to provide normal value of anteroposterior and rotational stability of knee joints using navigation system. Materials and Methods: From March 2007 to November 2007, 35 patients (23 men, 12 women) with a mean age of 36.1(16-57) years, who were treated with arthroscopy, without ligament injury of knee were included in our study. We measured amount of anteroposterior displacement and rotation of the knee in 0, 30, 60 and 90 degrees of flexion position using Orthopilot navigation system. All tests were performed by same single surgeon under manual maximal force. Results: The mean anterior displacement was 3.7⫾2.0, 6.6⫾2.2, 5.8⫾2.0 and 4.7⫾1.8 mm in 0, 30, 60 and 90 degrees of flexion respectively. The amount of anterior displacement at 30 degree of flexion was significantly larger than those of other degrees. The mean posterior displacement was 2.0⫾0.5, 2.2⫾0.4, 2.1⫾0.4 and
ABSTRACTS 2.0⫾0.6 at each degree. There was no statistical difference in posterior displacement. The mean internal rotation was 10.3⫾2.7, 14.6⫾3.3, 16.2⫾2.9 and 15.0⫾4.3 degree at each degree. The amount of internal rotation at 0 degree of flexion was significantly smaller than those of other degrees. The mean external rotation was 8.4⫾3.4, 16.5⫾3.3, 13.3⫾3.8 and 15.0⫾4.3 degree at each degree. The amount of external rotation at 0 degree of flexion was significantly smallest and that of 30 degree was largest. Conclusion: In the measurement of laxity using navigation, we could acquire previously mentioned results. The measurement of stability of knee will be useful in diagnosing ligament injury and evaluating degree of postoperative symptomatic improvement. Paper 156: Minimally Invasive Total Knee Replacement Does Not Reduce Surgical Stress Response BREGJE JW THOMASSEN, MSC, NETHERLANDS, PRESENTING AUTHOR J TEN CATE, MD, NETHERLANDS W.F. DRAIJER, NETHERLANDS NANNE P KORT, MD, PHD, NETHERLANDS ABSTRACT Introduction: The stress-response to surgery, known as a variety of well-characterized hormonal, metabolic, haematological and immunological changes, may be smaller in less invasive operations. Decreased blood loss, less soft tissue damage and inflammation leading to fast recovery are arguments used in promoting minimal invasive surgery (MIS). Purpose: Does MIS TKR with the subvastus approach lead to less inflammation and muscle damage than conventional TKR with the medial parapatellar approach? Material and Methods: Inflammation parameters (IL-6, IL-8 and IL-10, and CRP), muscle damage parameters (myoglobin, CK) and Hb values were determined preoperative and at 5 moments postoperative in 41 patients. Twenty patients operated through a MIS subvastus approach were compared to 21 patients with the standard medial parapatellair approach. Results: Average age in was 69.2 yrs in conventional TKR (contr) versus 68.9 yrs in MIS. The Hb levels were 13.9 g/dl preoperative and decreased to 10.8 g/dl (contr) and 11.6 g/dl (MIS) 72 hours postoperative. The mean IL-6 concentration increased from 6.8 (contr) vs 1.3 (MIS) pg/ml to 68.8 (contr) vs 45.1 (MIS) pg/ml 6 hours postoperative. The mean myoglobin concentration increased in TKP group from 47.7 ug/l preoperative to 90.1 ug/l 6 hours postoperative, the values for MIS were 27.8 g/l preoperative and 202.3 ug/l 6
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hours postoperative, with significant differences at 2, 4, 6 hrs and day 1 post-operative. Conclusion: Haemoglobin levels show no significant differences between conventional and MIS approach. Inflammation parameters were not significant different between the two groups. Myoglobin was the only muscle damage parameter with significant differences on several time points between both approaches. This may be explained by the used forces on surrounded tissues. The retractors are necessary to visualise the knee joint in MIS. These results show a trend towards more muscle damage compared to conventional TKR.
Paper 157: MIS versus Standard TKR: A Prospective Randomized Double Blinded Study Comparing Postoperative Strength and Functional Recovery BRYAN J NESTOR, M.D., USA, PRESENTING AUTHOR KRISTIN FOOTE, M.ED., USA STEPHEN L LYMAN, PHD, USA SHERRY I BACKUS, P.T., USA RUSSELL E WINDSOR, MD, USA ABSTRACT Introduction: Advantages of MIS TKR include less postoperative pain and improved early range of motion. However, all studies to date are either retrospective or at best prospective comparisons with matched controls and as such fail to control for patient expectations/placebo effect and in many cases selection bias. The purpose of this study was to determine whether the MIS midvastus approach to TKR resulted in quantitative differences in quadriceps muscle strength as well as the previously cited advantages. Methods: Sixteen patients (32 TKR’s) scheduled to undergo bilateral TKR were randomized to undergo a midvastus MIS on one knee and a standard quad-splitting approach on the other. The length of the skin incisions were made the same allowing for both patients and investigators to be blinded. The primary outcome was post-operative strength as determined by Biodex isokinetic and isometric peak torque testing. Secondary outcome measures included range of motion, pain visual analog scores, and gait analysis. Outcomes were assessed preoperatively and on postoperative day 1, 2, 3 and week 3, 6 and 12. Results: The only significant difference in strength testing was an increased isokinetic extensor torque at the 3 week postoperative time point for the MIS midvastus approach. No other significant differences were observed. No differences between the MIS midvastus and standard approach were observed for stride length, stance
ABSTRACTS
was obtained with C-arm of Arcadis Orbic (Siemens, Germany). The image was transferred to a navigation system (StealthStation navigation system, Medtronic, Louisville, CO) and reconstructed into a 3D image of the distal femur. During placement of guide wires for femoral tunnels through an accessory medial portal, a femoral guide with a tracker feed backed surgeons the direction of the guide wire on the 3D femur bone surface image with real time fashion. The femoral guide was placed at the center of the footprint with help of visual guidance of the navigation as well as an arthroscopic view. Then, flexion angle of the knee was adjusted to prevent posterior blowout on the computer screen during insertion of the guide wire. The length of the femoral tunnel could also be estimated before over drilling the guide wire. This technology assists surgeons to place two femoral tunnels precisely without any complication during anatomic double-bundle ACL reconstruction.
Paper 154: Navigation Evaluation of Pivot Shift During Anatomical Double-bundle ACL Reconstruction YASUYUKI ISHIBASHI, MD, JAPAN, PRESENTING AUTHOR EIICHI TSUDA, MD, JAPAN AKIRA FUKUDA, MD, JAPAN YUJI YAMAMOTO, MD, JAPAN, HAREHIKO TSUKADA, MD, JAPAN SATOSHI TOH, MD, JAPAN ABSTRACT Objective: Anterolateral rotatory instability (pivot shift) causes disability in anterior cruciate ligament (ACL) deficient knees, and sometimes even in ACL reconstructed knees. Therefore the interest that double-bundle ACL reconstruction (DB-ACLR) that reproduces anteromedial (AM) and posterolateral (PL) bundles of the ACL has risen. However, it is still unknown which of the AM and PL bundle is more important to prevent pivot shift phenomenon. The purpose of this study was to assess which bundle prevents pivot shift during DB-ACLR using a navigation system. Materials and Methods: Eighty patients, who received DB-ACLR using a navigation, were included in this study. Their mean age was 21.3 years. During DBACLR, pivot shift tests were performed four times at before reconstruction, and at after only PLB fixation, only AMB fixation, and both PLB and AMB fixation. Tibial internal rotation and anterior translation were measured at each phase by the additional functions of the navigation. The navigation system used in this study was OrthoPilot ACL ver 2.0 (B/Braun Aesculap, Germany), which was image-free navigation.
Results: Before ACL reconstruction, tibial internal rotation and anterior translation were 22.9⫾7.6° and 5.4⫾2.5mm. After PLB fixation, internal rotation and anterior translation significantly decreased to 19.5⫾7.5° and 2.2⫾0.9mm. After AMB fixation, they both decreased to 21.6⫾6.7° and 2.4⫾0.9mm. After PLB and AMB fixation (DB-ACLR), these data were improved to 19.0⫾7.3° and 2.0⫾0.7mm. Conclusions: Although it is well known that the ACL is a primary restraint of the knee under anterior tibial load, the role of the ACL in resisting internal tibial torque and the pivot shift test is controversial. To our knowledge, this is the first study which assess the functions of AM and PL bundle of ACL to prevent pivot shift phenomenon in vivo. Our data indicate that both AMB and PLB play a role in restraining not only anterior translation but also internal rotation during pivot shift test, and DBACLR improves knee stability. These findings are also consistent with previous in-vitro biomechanical studies, which measured in-situ forces of each bundle of the ACL. Paper 155: Measurement of Anteroposterior and Rotational Stability of Knee using Navigation System EUN KYOO SONG, MD, KOREA, PRESENTING AUTHOR TAEK RIM YOON, MD, SOUTH KOREA YOUNG JIN KIM, MD, SOUTH KOREA CHANG ICH HUR, MD, SOUTH KOREA KYUNG SOON PARK, MD, SOUTH KOREA DAM SEON LEE, MD, SOUTH KOREA JONG KEUN SEON, MD, SOUTH KOREA SANG JIN PARK, MD, SOUTH KOREA ABSTRACT Purpose: The aim of study was to provide normal value of anteroposterior and rotational stability of knee joints using navigation system. Materials and Methods: From March 2007 to November 2007, 35 patients (23 men, 12 women) with a mean age of 36.1(16-57) years, who were treated with arthroscopy, without ligament injury of knee were included in our study. We measured amount of anteroposterior displacement and rotation of the knee in 0, 30, 60 and 90 degrees of flexion position using Orthopilot navigation system. All tests were performed by same single surgeon under manual maximal force. Results: The mean anterior displacement was 3.7⫾2.0, 6.6⫾2.2, 5.8⫾2.0 and 4.7⫾1.8 mm in 0, 30, 60 and 90 degrees of flexion respectively. The amount of anterior displacement at 30 degree of flexion was significantly larger than those of other degrees. The mean posterior displacement was 2.0⫾0.5, 2.2⫾0.4, 2.1⫾0.4 and
ABSTRACTS 2.0⫾0.6 at each degree. There was no statistical difference in posterior displacement. The mean internal rotation was 10.3⫾2.7, 14.6⫾3.3, 16.2⫾2.9 and 15.0⫾4.3 degree at each degree. The amount of internal rotation at 0 degree of flexion was significantly smaller than those of other degrees. The mean external rotation was 8.4⫾3.4, 16.5⫾3.3, 13.3⫾3.8 and 15.0⫾4.3 degree at each degree. The amount of external rotation at 0 degree of flexion was significantly smallest and that of 30 degree was largest. Conclusion: In the measurement of laxity using navigation, we could acquire previously mentioned results. The measurement of stability of knee will be useful in diagnosing ligament injury and evaluating degree of postoperative symptomatic improvement. Paper 156: Minimally Invasive Total Knee Replacement Does Not Reduce Surgical Stress Response BREGJE JW THOMASSEN, MSC, NETHERLANDS, PRESENTING AUTHOR J TEN CATE, MD, NETHERLANDS W.F. DRAIJER, NETHERLANDS NANNE P KORT, MD, PHD, NETHERLANDS ABSTRACT Introduction: The stress-response to surgery, known as a variety of well-characterized hormonal, metabolic, haematological and immunological changes, may be smaller in less invasive operations. Decreased blood loss, less soft tissue damage and inflammation leading to fast recovery are arguments used in promoting minimal invasive surgery (MIS). Purpose: Does MIS TKR with the subvastus approach lead to less inflammation and muscle damage than conventional TKR with the medial parapatellar approach? Material and Methods: Inflammation parameters (IL-6, IL-8 and IL-10, and CRP), muscle damage parameters (myoglobin, CK) and Hb values were determined preoperative and at 5 moments postoperative in 41 patients. Twenty patients operated through a MIS subvastus approach were compared to 21 patients with the standard medial parapatellair approach. Results: Average age in was 69.2 yrs in conventional TKR (contr) versus 68.9 yrs in MIS. The Hb levels were 13.9 g/dl preoperative and decreased to 10.8 g/dl (contr) and 11.6 g/dl (MIS) 72 hours postoperative. The mean IL-6 concentration increased from 6.8 (contr) vs 1.3 (MIS) pg/ml to 68.8 (contr) vs 45.1 (MIS) pg/ml 6 hours postoperative. The mean myoglobin concentration increased in TKP group from 47.7 ug/l preoperative to 90.1 ug/l 6 hours postoperative, the values for MIS were 27.8 g/l preoperative and 202.3 ug/l 6
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hours postoperative, with significant differences at 2, 4, 6 hrs and day 1 post-operative. Conclusion: Haemoglobin levels show no significant differences between conventional and MIS approach. Inflammation parameters were not significant different between the two groups. Myoglobin was the only muscle damage parameter with significant differences on several time points between both approaches. This may be explained by the used forces on surrounded tissues. The retractors are necessary to visualise the knee joint in MIS. These results show a trend towards more muscle damage compared to conventional TKR.
Paper 157: MIS versus Standard TKR: A Prospective Randomized Double Blinded Study Comparing Postoperative Strength and Functional Recovery BRYAN J NESTOR, M.D., USA, PRESENTING AUTHOR KRISTIN FOOTE, M.ED., USA STEPHEN L LYMAN, PHD, USA SHERRY I BACKUS, P.T., USA RUSSELL E WINDSOR, MD, USA ABSTRACT Introduction: Advantages of MIS TKR include less postoperative pain and improved early range of motion. However, all studies to date are either retrospective or at best prospective comparisons with matched controls and as such fail to control for patient expectations/placebo effect and in many cases selection bias. The purpose of this study was to determine whether the MIS midvastus approach to TKR resulted in quantitative differences in quadriceps muscle strength as well as the previously cited advantages. Methods: Sixteen patients (32 TKR’s) scheduled to undergo bilateral TKR were randomized to undergo a midvastus MIS on one knee and a standard quad-splitting approach on the other. The length of the skin incisions were made the same allowing for both patients and investigators to be blinded. The primary outcome was post-operative strength as determined by Biodex isokinetic and isometric peak torque testing. Secondary outcome measures included range of motion, pain visual analog scores, and gait analysis. Outcomes were assessed preoperatively and on postoperative day 1, 2, 3 and week 3, 6 and 12. Results: The only significant difference in strength testing was an increased isokinetic extensor torque at the 3 week postoperative time point for the MIS midvastus approach. No other significant differences were observed. No differences between the MIS midvastus and standard approach were observed for stride length, stance