Avoiding Complications with MPFL Reconstruction

Abstract

Multiple cadaveric studies have characterized the anatomy of the MPFL and the related morphologic abnormalities that contribute to recurrent lateral patellar instability. Such abnormalities include patella alta, excessive tibial tubercle to trochlear grove (TT-TG) distance, trochlear dysplasia, and malalignment. Recent studies have evaluated the clinical outcomes associated with the treatment of concomitant pathology in combination with MPFL reconstruction, which is critical in avoiding recurrent instability and complications. Although there remains a lack of consensus regarding various critical aspects of MPFL reconstruction, certain concepts remain imperative. Our preferred methods and rationales for surgical techniques are described. These include appropriate work up, a combination of procedures to address abnormal morphology, anatomical femoral insertion, safe and secure patellar fixation, appropriate graft length fixation, and thoughtful knee flexion during fixation.

Recurrent Patellofemoral Instability in the Pediatric Patient: Management and Pitfalls

“…Patella alta can be determined through a variety of methods (e.g., Insall-Salvati ratio (normal 0.8-1.2), Caton-Deschamps index (normal 0.6-1.3), Blackburn-Peel ratio (normal 0.5-1.0)) by evaluating a lateral radiograph of the knee [12]. Correction of patellar height via a tibial tubercle distalization procedure helps confer stability to the patellofemoral articulation via early patellar engagement but is reserved for patients who are skeletally mature [28]. However, care should be taken with distalization procedures to avoid increasing patellofemoral contact pressures and iatrogenic early PFJ arthrosis.…”

“…Appropriate tensioning to allow for a checkrein through a large arc of motion while not overtightening the ligament is important in recreating the normal anatomy. Appropriate tensioning has been demonstrated as 2 N and should be assessed along with graft isometry through the knee range of motion intraoperatively [28]. Over-tensioning can lead to stiffness, early arthritis, and tension-induced fractures at the superior pole or medial rim.…”

Small, Short, Oblique Patellar Tunnels for Patellar Fixation Do Not Increase Fracture Risk or Complications in MPFL Reconstruction: A Retrospective Cohort Study

“…The MPFL reconstruction was undertaken in the manner previously described by Smith et al 24 to re-create the sail shape of the native MPFL, with its attachment on the † Address correspondence to Thomas E. Moran, MD, 710 Walker Square, Apt #3D, Charlottesville, VA 22903, USA (email: tem9rs@virginia.edu). *Department of Orthopaedic Surgery, University of Virginia, Charlottesville, Virginia, USA.…”

Small (3.2-mm), Short, Oblique Patellar Tunnels for Patellar Fixation in MPFL Reconstruction

“…A full summary on the evaluation of patellar instability is outside the scope of this Technical Note, but history taking should detail the instability events themselves and help the surgeon to identify the frequency and chronicity of such events. 9 Detailed history, physical exam, and radiographic evaluation are vital to identify the presence of primary anatomic risk factors of patellar instability, including trochlear dysplasia, coronal malalignment manifested as genu valgum or elevated tibial tubercle-trochlear groove (TT-TG) distance, femoral anteversion, and patella alta. 1 We acquire a standard 3-view radiographic series, including a standing flexion posteroanterior, lateral, and 45° flexed axial Merchant view of the knee as part of our initial imaging workup.…”