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Troubleshooting the Femoral Attachment During Medial Patellofemoral Ligament Reconstruction: Location, Location, Location.

Burrus MT, Werner BC, Conte EJ, Diduch DR - Orthop J Sports Med (2015)

Bottom Line: Appropriately, significant research has been undertaken regarding graft biomechanics and techniques, as intraoperative errors in graft placement often result in poor patient outcomes.Using a sawbones knee model, the concepts of an MPFL graft that is "high and tight" or "low and loose" are presented, with the goal of providing physicians with intraoperative tools to adjust an incorrectly placed femoral MPFL attachment.This model is also used to justify the recommendation of graft fixation in 30° to 45° of knee flexion.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.

ABSTRACT
The medial patellofemoral ligament (MPFL) has been recognized as an important soft tissue restraint in preventing lateral patellar translation. As many patients with acute or chronic patellar instability will have a deficient MPFL, reconstruction of this ligament is becoming more common. Appropriately, significant research has been undertaken regarding graft biomechanics and techniques, as intraoperative errors in graft placement often result in poor patient outcomes. Although the research has not answered all of the dilemmas encountered during reconstruction, publications consistently emphasize the importance of re-establishing an anatomic femoral attachment. The purpose of this study was to briefly review the current literature on MPFL reconstruction. Graft selection and patellar graft attachment and fixation are discussed, but the main focus is the femoral attachment as this is where most errors are seen and, unfortunately, where getting it right appears to matter the most. Using a sawbones knee model, the concepts of an MPFL graft that is "high and tight" or "low and loose" are presented, with the goal of providing physicians with intraoperative tools to adjust an incorrectly placed femoral MPFL attachment. This model is also used to justify the recommendation of graft fixation in 30° to 45° of knee flexion.

No MeSH data available.


Related in: MedlinePlus

The medial patellofemoral ligament (MPFL) attachment is defined in relation to the anterior-posterior size of the medial femoral condyle: If the anterior-posterior size is referred to as 100%, then the MPFL attachment is 40% from the posterior and 50% from the distal outline. (Reprinted with permission from Stephen JM, Lumpaopong P, Deehan DJ, Kader D, Amis AA. The medial patellofemoral ligament: location of femoral attachment and length change patterns resulting from anatomic and nonanatomic attachments. Am J Sports Med. 2012;40:1871-1879. ©2012, The American Orthopaedic Society for Sports Medicine.)
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fig3-2325967115569198: The medial patellofemoral ligament (MPFL) attachment is defined in relation to the anterior-posterior size of the medial femoral condyle: If the anterior-posterior size is referred to as 100%, then the MPFL attachment is 40% from the posterior and 50% from the distal outline. (Reprinted with permission from Stephen JM, Lumpaopong P, Deehan DJ, Kader D, Amis AA. The medial patellofemoral ligament: location of femoral attachment and length change patterns resulting from anatomic and nonanatomic attachments. Am J Sports Med. 2012;40:1871-1879. ©2012, The American Orthopaedic Society for Sports Medicine.)

Mentions: Intraoperatively, a formal dissection to visually locate the femoral origin of the MPFL for proper tunnel placement is unnecessary thanks to research by Schottle et al,18 which correlated the fluoroscopic and anatomic location of the MPFL. The fluoroscopic location of the femoral origin of the MPFL has come to be known as the Schottle point. The first reference for the Schottle point is a line continued distally from the posterior femoral cortex. The second reference uses 2 lines that are perpendicular to the first: 1 at the posterior aspect of the Blumensaat line and the second at the transition of the curve of the posterior femoral condyles. The Schottle point rests 2 mm anterior to the posterior cortical line between the 2 perpendicular lines (Figure 2). It is critical to obtain a perfect lateral of the distal femur, as slight rotational or angular variations will lead to nonanatomic graft placement. Once the tip of the guide pin rests exactly on the Schottle point, it should be driven across the femur while being careful to not aim too distal or too posterior. Another method to find the femoral origin of the MPFL uses fluoroscopy to divide the distal femur into percentages based off of the anterior to posterior dimensions of the distal femur (Figure 3).26 Once the pin is placed and the graft tunneled between the medial layers of the knee, the graft can then be wrapped around the pin and tensioned while the knee is taken through a complete range of motion to assess isometry (Figure 1B).


Troubleshooting the Femoral Attachment During Medial Patellofemoral Ligament Reconstruction: Location, Location, Location.

Burrus MT, Werner BC, Conte EJ, Diduch DR - Orthop J Sports Med (2015)

The medial patellofemoral ligament (MPFL) attachment is defined in relation to the anterior-posterior size of the medial femoral condyle: If the anterior-posterior size is referred to as 100%, then the MPFL attachment is 40% from the posterior and 50% from the distal outline. (Reprinted with permission from Stephen JM, Lumpaopong P, Deehan DJ, Kader D, Amis AA. The medial patellofemoral ligament: location of femoral attachment and length change patterns resulting from anatomic and nonanatomic attachments. Am J Sports Med. 2012;40:1871-1879. ©2012, The American Orthopaedic Society for Sports Medicine.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4555580&req=5

fig3-2325967115569198: The medial patellofemoral ligament (MPFL) attachment is defined in relation to the anterior-posterior size of the medial femoral condyle: If the anterior-posterior size is referred to as 100%, then the MPFL attachment is 40% from the posterior and 50% from the distal outline. (Reprinted with permission from Stephen JM, Lumpaopong P, Deehan DJ, Kader D, Amis AA. The medial patellofemoral ligament: location of femoral attachment and length change patterns resulting from anatomic and nonanatomic attachments. Am J Sports Med. 2012;40:1871-1879. ©2012, The American Orthopaedic Society for Sports Medicine.)
Mentions: Intraoperatively, a formal dissection to visually locate the femoral origin of the MPFL for proper tunnel placement is unnecessary thanks to research by Schottle et al,18 which correlated the fluoroscopic and anatomic location of the MPFL. The fluoroscopic location of the femoral origin of the MPFL has come to be known as the Schottle point. The first reference for the Schottle point is a line continued distally from the posterior femoral cortex. The second reference uses 2 lines that are perpendicular to the first: 1 at the posterior aspect of the Blumensaat line and the second at the transition of the curve of the posterior femoral condyles. The Schottle point rests 2 mm anterior to the posterior cortical line between the 2 perpendicular lines (Figure 2). It is critical to obtain a perfect lateral of the distal femur, as slight rotational or angular variations will lead to nonanatomic graft placement. Once the tip of the guide pin rests exactly on the Schottle point, it should be driven across the femur while being careful to not aim too distal or too posterior. Another method to find the femoral origin of the MPFL uses fluoroscopy to divide the distal femur into percentages based off of the anterior to posterior dimensions of the distal femur (Figure 3).26 Once the pin is placed and the graft tunneled between the medial layers of the knee, the graft can then be wrapped around the pin and tensioned while the knee is taken through a complete range of motion to assess isometry (Figure 1B).

Bottom Line: Appropriately, significant research has been undertaken regarding graft biomechanics and techniques, as intraoperative errors in graft placement often result in poor patient outcomes.Using a sawbones knee model, the concepts of an MPFL graft that is "high and tight" or "low and loose" are presented, with the goal of providing physicians with intraoperative tools to adjust an incorrectly placed femoral MPFL attachment.This model is also used to justify the recommendation of graft fixation in 30° to 45° of knee flexion.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.

ABSTRACT
The medial patellofemoral ligament (MPFL) has been recognized as an important soft tissue restraint in preventing lateral patellar translation. As many patients with acute or chronic patellar instability will have a deficient MPFL, reconstruction of this ligament is becoming more common. Appropriately, significant research has been undertaken regarding graft biomechanics and techniques, as intraoperative errors in graft placement often result in poor patient outcomes. Although the research has not answered all of the dilemmas encountered during reconstruction, publications consistently emphasize the importance of re-establishing an anatomic femoral attachment. The purpose of this study was to briefly review the current literature on MPFL reconstruction. Graft selection and patellar graft attachment and fixation are discussed, but the main focus is the femoral attachment as this is where most errors are seen and, unfortunately, where getting it right appears to matter the most. Using a sawbones knee model, the concepts of an MPFL graft that is "high and tight" or "low and loose" are presented, with the goal of providing physicians with intraoperative tools to adjust an incorrectly placed femoral MPFL attachment. This model is also used to justify the recommendation of graft fixation in 30° to 45° of knee flexion.

No MeSH data available.


Related in: MedlinePlus