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Trochleoplasty has its place for select patients with complex patella instability
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Controversial in the patellofemoral surgery world are indications for trochleoplasty. David Dejour, MD, and Philip Schoettle, MD, PhD, continuing the landmark trochlea classification work of Henri Dejour, MD, have studied and recommended trochleoplasty in the treatment of select patients with patella instability. Several surgeons, mostly in Europe, report good results.
There is little doubt that it is helpful in some patients with a prominent supratrochlear spur or a convex proximal trochlea, but it is an intra-articular procedure with increased risk of stiffness and unknown long-term consequences to articular cartilage. Many, if not most, of these patients also have a medial patellofemoral ligament (MPFL) reconstruction done at the same time. It is not always clear how much the trochleoplasty has added to stability.
Joseph N. Liu, MD, Beth Shubin Stein, MD, and others at Hospital for Special Surgery have established the efficacy of MPFL reconstruction alone for most recurrent patella instability patients despite trochlea dysplasia, without doing a trochleoplasty.
My experience of more than 40 years of doing surgery for patients with patella instability, which comprises more than 800 patients, is similar to this experience at Hospital for Special Surgery. Few patients in the course of my career thus far (as I am still operating) have required trochleoplasty. Nonetheless, I believe there is a place for it in select patients.
The challenge now is to establish which patient needs a trochleoplasty. If a patient will be stable, pain free, active and happy without a trochleoplasty, then the added risks of arthrotomy, subchondral bone disruption and articular alteration are best avoided.
Rotational abnormalities
Rotational abnormalities come into play, and some patients benefit from correction of patella tracking — getting the patella into better alignment with the trochlea. Tibial tubercle transfer (TTT) or tibial tubercle osteotomy is a powerful procedure for this purpose, when needed, even as a compensatory procedure for excessive femoral internal rotation. I prefer anteromedialization (AMZ) of the tibial tuberosity in patients with distal articular lesions to reduce the risk of adding load to an area of damage. In a small number of patients, a distal femoral rotation osteotomy (DFO) of the femur may be necessary. The recurrences I have seen are related mostly to under-correction or underestimation of a rotational alignment problem in the face of trochlea dysplasia. Regardless of trochleoplasty, rotational alignment abnormalities should be treated at the time of patella instability surgery.
Difficult procedure to do well
Trochleoplasty is a difficult procedure to do well and choosing an appropriate patient requires much experience. I believe it is best done by an experienced patellofemoral surgeon for patients with a convex proximal trochlea and supratrochlear spur in the surgical treatment of complex patella instability. This is most often the case when rotational alignment must be treated by osteotomy and the trochlea is convex, leaving a significant lateral displacement force vector on the patella even when alignment has been optimized, particularly in patients with ligament laxity. In my experience, this is a small number of patients with patella instability. Such patients will almost always also benefit from an MPFL reconstruction. The orthopedic surgeon should warn patients that stiffness is more likely when a trochleoplasty is done and the rehabilitation plan should be adjusted accordingly.
Trochleoplasty is a useful procedure when properly done for highly selected patients with complex patella instability related to rotational malalignment that has caused a secondary convex trochlea dysplasia. Form follows function. Correction of rotational malalignment and/or MPFL reconstruction are usually appropriate at the time of trochleoplasty.
Trochleoplasty should be added only when MPFL reconstruction with or without rotational control osteotomy, such as TTT, AMZ or DFO, are insufficient. Trochleoplasty carries additional risks. Most patients with recurrent patella instability and trochlea dysplasia can be treated effectively and safely without doing a trochleoplasty.
- Reference:
- Liu JN, et al. Amer J Sports Med. 2018; doi:10.1177/0363546517745625.
- For more information:
- John P. Fulkerson, MD, is a clinical professor of orthopedic surgery at University of Connecticut School of Medicine and practices at Orthopedic Associates of Hartford in Farmington, Connecticut. He is also president of The Patellofemoral Foundation.
Disclosure: Fulkerson reports no relevant financial disclosures.