Patellar instability remains an issue in modern total knee replacement

Patellar instability remains a challenging issue in modern total knee replacement patients. Total knee replacement has consistently been shown as a highly successful treatment for degenerative arthritis of the knee, but 33% to 50% of revision surgeries for this procedure in the 2-year to 5-year postoperative period have been attributed to patellar instability. In addition, patellar positioning in postoperative TKR patients shows up to a 15% chance of more than 5 mm of lateral patellar displacement from the trochlear groove.

James Bicos MD, Healio Orthopedics Today January 29, 2016.

In order to perform a total knee replacement (TKR), most surgeons perform a medial para-patellar arthrotomy that sacrifices the medial patellofemoral ligament (MPFL) to achieve an adequate surgical exposure. As we know, the MPFL serves as a static restraint to lateral patellar subluxation in the native knee.

Therefore, our hypothesis was to examine whether routine anatomic MPFL repair via a direct suture repair technique prior to arthrotomy closure in TKR patients prevented excessive mediolateral patellar translation.

Despite a small trend of greater preoperative tilt in these patients, out of 46 patients categorized into either a standard closure group (n=29) or an MPFL closure group (n=17), patients undergoing TKR with reconstitution (i.e., repair) of the MPFL prior to arthrotomy closure demonstrated a significantly smaller degree of postoperative lateral patellar tilt and subluxation at 4 months postoperatively compared with patients who had a standard arthrotomy closure.

As we continue to examine and research the anatomy of patellofemoral articulation, we consistently see the need for thoughtful anatomic repair of the structures we tend to violate during surgical dissections. This article shows the need for anatomic repair of all the structures of a medial patellar arthrotomy including the MPFL.

Source Healio Orthopedics Today

Repair of Medial Patellofemoral, Ligament Improves Patellar, Tracking in Total Knee Replacement, Meneghini RM, Ziemba-Davis M, Smits S, Bicos J. Surg Technol Int. 2015 Nov;27:275-8.

Also see
Anatomy and biomechanics of the medial patellofemoral ligament, Amis AA, Firer P, Mountney J, Senavongse W, Thomas NP. Knee. 2003 Sep;10(3):215-20.
Patellar clunk syndrome more common with high-flex bearing than fixed-bearing TKA in Healio Orthopedics Today
Recent Patellofemoral Findings at The Patellofemoral Foundation
Tips to Prevent Runner’s Knee in Popsugar
Why Did My Knees Hurt When I Started Back in Running? in Livestrong
Stretches to Ease Hip & Knee Pain in Healthguru

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