Patellofemoral Update focuses on the causes, prevention and treatment of patellofemoral disorders. The blog is sponsored by The Patellofemoral Foundation whose mission is to improve the care of individuals with anterior knee pain through targeted education and research. The Patellofemoral Foundation offers additional online education resources on its website.

BLOG: Combined reconstruction of the MPFL and MQTFL for patellar instability in children and adolescents

Robert Spang MD
Robert C. Spang

Recurrent patellar instability, particularly in the skeletally immature patient, presents a challenging problem. While the best treatment option remains unclear, MPFL reconstruction has become increasingly common in the past 2 decades. Previously described methods are numerous and include variations in terms of patellar/femoral fixation, graft type and angle of knee flexion at time of fixation.

Although studies have shown the medial patellofemoral ligament (MPFL) is the primary restraint to lateral translation of the patella, multiple cadaveric studies have identified an anatomically distinct structural component of the medial retinaculum extending from the region of the MPFL origin and inserting anteriorly into the distal quadriceps tendon rather than the patella itself. Recently, Fulkerson described a surgical technique for reconstructing this medial quadriceps tendon-femoral ligament (MQTFL). Avoidance of patellar fixation by using this technique has the potential to decrease the risk of patellar fracture, a devastating complication.

Our group recently published a study that described a combined reconstruction technique involving both the MPFL and the MQTFL and reported patient outcomes of a single-surgeon series. Using this technique, the midpoint of an Achilles allograft is fixed to Schottle’s point on the distal femur via suture anchor. Both limbs are shuttled deep to the medial retinaculum. One limb, the MPFL reconstruction limb, is fixed to the medial patellar border at the junction of the proximal one-third and distal two-thirds of the patella again via suture anchor. The other limb, or the MQTFL reconstruction limb, is looped around a small incision in the vastus medialis oblique (VMO)tendon at the level of the proximal patella and sutured to the underlying VMO. In this way, both the MPFL and MQTFL are reconstructed.

A total of 25 patients with a mean age of 15 years underwent combined MPFL and MQTFL reconstruction in 27 knees between February 2012 and January 2015. Twenty percent also underwent simultaneous guided growth arrest via hemiepiphysiodesis for valgus deformity at the time of combined reconstruction. A total of 18 patients (19 knees, 72%) returned outcomes questionnaires at a mean of 2 years after surgery. Mean Kujala, pedi-IKDC and Lysholm scores were 85.9, 81.5, and 84.3, respectively. Two patients (8%) later required revision procedures (tibial tubercle osteotomy) for recurrent patellar instability at the time of skeletal maturity.

The study describes an anatomically validated combined reconstruction technique with overall favorable short-term outcomes. This technique is particularly useful in the skeletally immature patient when tibial tubercle osteotomy should be avoided and patellar fixation minimized to avoid fracture. MQTFL reconstruction can also be useful in the revision setting. The importance of overall limb alignment should not be overlooked in this diverse and challenging patient population, as the opportunity to use guided-growth arrest in the skeletally immature patients with recurrent instability and valgus alignment should be strongly considered. 

 

Reference:

Spang RC, et al. J Pediatr Orthop. 2018;doi:10.1097/BPO.0000000000001259.

Disclosure: Spang reports no relevant financial disclosures.

 

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