This article is more than 5 years old. Information may no longer be current.
Distalization of the patella to correct patella alta in patients with patella instability
Click Here to Manage Email Alerts
Editor’s note: Members of the Patellofemoral Foundation review and add clinical perspective to recently published studies on the causes, prevention and treatment of patellofemoral disorders. The twice monthly blogs are edited by John Fulkerson, MD, and can be found on www.healio.com/orthopaedics.
The review of the available literature by Robert A. Magnussen, MD, on this topic is timely as orthopaedic surgeons are increasingly interested in the correction of patella alta to control patella instability. Distalization of the tibial tuberosity brings the patella into the deeper part of the trochlear groove sooner in knee flexion, thereby affording improved stability and diminished likelihood of dislocation. When the trochlea is shallow, distalization makes sense.
As pointed out by Magnussen and colleagues, the question remains as to when other procedures such as medial tubercle transfer or reconstruction of the medial capsular structures, including the medial patellofemoral ligament (MPFL), might be warranted in addition to, or instead of, patella distalization. Many surgeons have achieved patella stability for years by assuring proper alignment/tracking of the patella in the trochlear groove and then restoring, by reconstruction, the medial support structures that support the patella as it slides along the trochlea with flexion and extension of the knee.
Surgical planning
We must proceed cautiously with surgical planning. In his review, Magnussen has shown that 15% to 33% of patients still have patella apprehension after patella distalization, so I agree with him that we must look carefully for what other procedures, such as tibial tubercle medialization and MPFL reconstruction, are likely to improve the patient’s outcome. This should be the goal of every patellofemoral surgeon.
From my own experience, many patients have a distal pole patella articular lesion that will less likely become painful if the tip (or “nose”) of the patella is anteriorized selectively at the time of patella realignment. Anteromedial tibial tubercle transfer accomplishes this and, in the presence of patella alta, may be distalized to correct alta while optimizing patella alignment and unloading the distal patella. A corollary of this is that distalization alone is risky in patients with distal pole patella articular softening, as this vulnerable area might experience increased loads with distalization alone. Accurate and thoughtful decision making is imperative here.
Optimal results
Dr. Magnussen emphasizes the importance of using complementary procedures as needed to assure an optimal result in each patient. I agree. I have found that patella distalization is needed only in more extreme cases of patella alta and that restoration of balanced patella tracking while unloading patella articular lesions and reconstructing peripatellar support structure is the best and most reliable approach to recurrent patella instability in the majority of patients I see.
- Reference:
- Magnussen RA. Knee Surg Sports Traumatol Arthrosc. 2013 Feb 8. [Epub ahead of print].
- For more information:
- John P. Fulkerson, MD, is clinical professor of orthopedic surgery at University of Connecticut School of Medicine and practices at Orthopedic Associates of Hartford, Farmington, Conn., USA. He is president of The Patellofemoral Foundation.
Disclosure: Fulkerson receives royalties from DJO Global and is a patent holder for DJO Global.
Perspective
Back to Top
David DeJour, MD
Patella alta is certainly one of the major factors for objective patellar dislocation and the article from Magnussen highlights this well. It is the factor that could lead to dislocation even without trochlear dysplasia.
The most important thing is to have some objective patellar height measurement and surgeons must use an index to quantify it. This is the best way to avoid any iatrogenic surgery, which could lead to undercorrection (iterative dislocation) or overcorrection (patella infera). The surgeons decision making for a distalization has to take in account this measurement and also the other factors, like tibial tubercle-trochlear groove, trochlear dysplasia and patellar tilt. The sagittal plane analysis is also interesting using MRI to look at the patellar tendon length and the sagittal engagement of the patella in the trochlea, as Biedert describes with the patellofemoral index. This gives a good view of the relationship between the trochlea and the patella and allows the surgeon to adapt the amount of distalization depending on the trochlear length to get the best patellar engagement in early flexion.
Click Here to Manage Email Alerts