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Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction (SS-76)
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ABSTRACTS
quadrants (P ⬍ 0.001). There was a significant increase in muscle atrophy from 30% to 70% at long-term (P ⫽ 0.021). There was no difference in retropatellar pain between initial (30%) and long-term (20%), however, there was an increase between mid-term (0%) and longterm (P ⫽ 0.045). There was no difference for knee range-of-motion. Improvement in all radiographic measurements were seen for congruence angle, lateral patellofemoral angle (LPFA), and lateral patellar displacement. Only the change from LPFA was significant (5.7° to 8.6°, P ⫽ 0.014). On Merchant view, 7 knees (35%) demonstrated a medial ossicle. Patellofemoral osteophytes were present in 10 knees (50%) and the majority of these knees had documented chondral pathology at the time of surgery. Conclusion: Arthroscopically assisted medial reefing, without lateral release, is an effective long-term treatment for patients with recurrent patellar instability and normal bony anatomy. Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction (SS-76) MARK MCCARTHY, M.D., PRESENTING AUTHOR ANNUNZIATO AMENDOLA, M.D. BRIAN R. WOLF, M.D., M.S. JOHN ALBRIGHT, M.D. MATTHEW BOLLIER, M.D. Introduction: In patients with chronic patellofemoral instability, medial patellofemoral ligament (MPFL) reconstruction is a good option to treat patella instability. However, few studies have looked at tunnel position after MPFL reconstruction. Servien, et al, recently examined femoral tunnel position one year after MPFL reconstruction. They found that 35% of tunnels were malpositioned. Bollier, et al, recently presented 5 cases of femoral tunnel malposition and found that medial subluxation, medial patellofemoral articular overload, and recurrent lateral instability are possible when the graft is positioned non-anatomically. When an MPFL graft is placed proximally on the femur, there is increased graft tension when the knee is flexed. Correct graft tensioning and anatomic tunnel position are important components of maximizing outcomes after this procedure. The purpose of this study is to examine femoral tunnel position on postoperative radiographs and determine if malpositioned tunnels are associated with poorer clinical outcomes. Methods: After IRB approval, we performed a retrospective chart review of MPFL reconstruction done at the University of Iowa from 2006-2010. Inclusion criteria included MPFL reconstruction with a femoral tunnel,
preoperative and postoperative lateral knee radiographs, and availability of outcome scores. We identified 15 isolated MPFL reconstruction and 35 combination MPFL reconstruction and tibial tubercle transfer. Demographic data was recorded. We then examined the best postoperative lateral radiograph to determine femoral tunnel position. Radiographic measurements were taken based on a variation in technique described by Schottle. We drew 1 line extending from the posterior femoral cortex, and 2 lines perpendicular lines to this, one at the intersection of the posterior femoral cortex and condyle, the other at the posterior most point of Blumensaat line. We then identified the mid-point on the posterior cortex line between the parallel antero-posterior lines. We defined this as the femoral isometric point. We then measured a distance in mm from this point to the center of the MPFL femoral tunnel. We defined anatomic tunnel position to be within 9 mm of the isometric point. Preoperative and postoperative KOOS scores were recorded. Results: Average age: 31.3 years (range, 14-54) Males10 Females- 40 64.8% of femoral tunnels were malposition on lateral radiographs Femoral tunnels were an average of 13.25 mm (4-28.4 mm) from the isometric position Average pre-op KOOS in isolated MPFL group: 42.0 Average post-op KOOS in isolated MPFL group: 47.65 Average pre-op KOOS in combo MPFL/TTT group: 37.29 Average post-op KOOS in isolated MPFL/ TTT group: 83.1. Conclusion: Our study showed that nearly 65% of femoral tunnels were malpositioned on postoperative radiographs. We advise appropriate exposure to identify the femoral MPFL insertion site between the medial epicondyle and adductor tubercle. A guide wire placed in this location can be confrimed under fluoroscopy and we highly recommend the use of fluoroscopy intraoperatively to assist in determining anatomic femoral tunnel position. Further studies are warranted to assess clinical outcomes on malpositioned MPFL grafts.
Cyclic Testing of 3 Medial Patellofemoral Ligament Reconstruction Techniques (SS-77) VISHAL M MEHTA, M.D., PRESENTING AUTHOR AHMED AKHTER, B.S. CASSIE MANDALA, P.A.C. Introduction: There are several techniques that can be utilized to fix the graft to the patella during Medial Patello-Femoral Ligament (MPFL) reconstruction. Despite this, the biomechanical properties of many of these techniques remain unknown. The purpose of this study is to compare the biomechanical properties of 3 MPFL
ABSTRACTS
quadrants (P ⬍ 0.001). There was a significant increase in muscle atrophy from 30% to 70% at long-term (P ⫽ 0.021). There was no difference in retropatellar pain between initial (30%) and long-term (20%), however, there was an increase between mid-term (0%) and longterm (P ⫽ 0.045). There was no difference for knee range-of-motion. Improvement in all radiographic measurements were seen for congruence angle, lateral patellofemoral angle (LPFA), and lateral patellar displacement. Only the change from LPFA was significant (5.7° to 8.6°, P ⫽ 0.014). On Merchant view, 7 knees (35%) demonstrated a medial ossicle. Patellofemoral osteophytes were present in 10 knees (50%) and the majority of these knees had documented chondral pathology at the time of surgery. Conclusion: Arthroscopically assisted medial reefing, without lateral release, is an effective long-term treatment for patients with recurrent patellar instability and normal bony anatomy. Femoral Tunnel Placement in Medial Patellofemoral Ligament Reconstruction (SS-76) MARK MCCARTHY, M.D., PRESENTING AUTHOR ANNUNZIATO AMENDOLA, M.D. BRIAN R. WOLF, M.D., M.S. JOHN ALBRIGHT, M.D. MATTHEW BOLLIER, M.D. Introduction: In patients with chronic patellofemoral instability, medial patellofemoral ligament (MPFL) reconstruction is a good option to treat patella instability. However, few studies have looked at tunnel position after MPFL reconstruction. Servien, et al, recently examined femoral tunnel position one year after MPFL reconstruction. They found that 35% of tunnels were malpositioned. Bollier, et al, recently presented 5 cases of femoral tunnel malposition and found that medial subluxation, medial patellofemoral articular overload, and recurrent lateral instability are possible when the graft is positioned non-anatomically. When an MPFL graft is placed proximally on the femur, there is increased graft tension when the knee is flexed. Correct graft tensioning and anatomic tunnel position are important components of maximizing outcomes after this procedure. The purpose of this study is to examine femoral tunnel position on postoperative radiographs and determine if malpositioned tunnels are associated with poorer clinical outcomes. Methods: After IRB approval, we performed a retrospective chart review of MPFL reconstruction done at the University of Iowa from 2006-2010. Inclusion criteria included MPFL reconstruction with a femoral tunnel,
preoperative and postoperative lateral knee radiographs, and availability of outcome scores. We identified 15 isolated MPFL reconstruction and 35 combination MPFL reconstruction and tibial tubercle transfer. Demographic data was recorded. We then examined the best postoperative lateral radiograph to determine femoral tunnel position. Radiographic measurements were taken based on a variation in technique described by Schottle. We drew 1 line extending from the posterior femoral cortex, and 2 lines perpendicular lines to this, one at the intersection of the posterior femoral cortex and condyle, the other at the posterior most point of Blumensaat line. We then identified the mid-point on the posterior cortex line between the parallel antero-posterior lines. We defined this as the femoral isometric point. We then measured a distance in mm from this point to the center of the MPFL femoral tunnel. We defined anatomic tunnel position to be within 9 mm of the isometric point. Preoperative and postoperative KOOS scores were recorded. Results: Average age: 31.3 years (range, 14-54) Males10 Females- 40 64.8% of femoral tunnels were malposition on lateral radiographs Femoral tunnels were an average of 13.25 mm (4-28.4 mm) from the isometric position Average pre-op KOOS in isolated MPFL group: 42.0 Average post-op KOOS in isolated MPFL group: 47.65 Average pre-op KOOS in combo MPFL/TTT group: 37.29 Average post-op KOOS in isolated MPFL/ TTT group: 83.1. Conclusion: Our study showed that nearly 65% of femoral tunnels were malpositioned on postoperative radiographs. We advise appropriate exposure to identify the femoral MPFL insertion site between the medial epicondyle and adductor tubercle. A guide wire placed in this location can be confrimed under fluoroscopy and we highly recommend the use of fluoroscopy intraoperatively to assist in determining anatomic femoral tunnel position. Further studies are warranted to assess clinical outcomes on malpositioned MPFL grafts.
Cyclic Testing of 3 Medial Patellofemoral Ligament Reconstruction Techniques (SS-77) VISHAL M MEHTA, M.D., PRESENTING AUTHOR AHMED AKHTER, B.S. CASSIE MANDALA, P.A.C. Introduction: There are several techniques that can be utilized to fix the graft to the patella during Medial Patello-Femoral Ligament (MPFL) reconstruction. Despite this, the biomechanical properties of many of these techniques remain unknown. The purpose of this study is to compare the biomechanical properties of 3 MPFL