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Trochleoplasty may be a good solution for patients with patellar instability with dysplasia
LAS VEGAS — A presenter at the Arthroscopy Association of North America and American Orthopaedic Society for Sports Medicine Specialty Day at the American Academy of Orthopaedic Surgeons Annual Meeting discussed factors orthopedic surgeons should look for when they consider trochleoplasty in patients with patellar instability with dysplasia.
“It is technically demanding and certainly frightening when you first start doing trochleoplasty but at least for some patients, it’s a good surgical solution; in fact, the best surgical solution for stabilization,” Julian Feller, MD, said during his presentation.
He added, “The key theme is to remove the supratrochlear spur.”
Feller said there are four grades of dysplasia: types A, B, C and D, with types B and D being high grades of dysplasia. High-grade dysplasia is defined by the presence of supratrochlear spurs, and these patients have significant symptoms such as habitual dislocations. He said key considerations for trochleoplasty include a large J-sign on the physical examination and no significant patella alta.
Feller said surgeons should pay attention to patella alta because patients may need an alternative procedure if its significant .
“[The] decision to consider trochleoplasty is based on a combination of patient factors — a large J-sign, significant disability and instability, and imaging factors that show the presence of supratrochlear spur,” Feller said. “Importantly, know that patella alta may need an alternative procedure.”– by Monica Jaramillo
Reference:
Feller J. Patella instability with dysplasia: My surgical algorithm. Presented at: Arthroscopy Association of North American and American Orthopaedic Society for Sports Medicine Specialty Day at the American Academy of Orthopaedic Surgeons Annual Meeting; March 16, 2019; Las Vegas.
Disclosure: Feller reports he is on the editorial or governing board of the American Journal of Sports Medicine, Knee Surgery, Sports Traumatology, Arthroscopy, Orthopaedic Journal of Sports Medicine; is a board or committee member of the International Society of Arthroscopy, Knee Surgery, and Orthopaedic Sports Medicine and is a paid presenter or speaker for Smith & Nephew.
Perspective
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The report on Feller’s AANA Specialty Day presentation at AAOS highlights his approach to trochleoplasty. Students of the patellofemoral compartment have followed an evolution of the management of patellar instability noting in the past, there were advocates of isolated lateral release, isolated tubercle medialization, isolated medial reefing and combinations. There is now general agreement that the common denominator for patellar instability is patholaxity of the proximal medial patellar restraints (medial patellofemoral [MPFL] and medial quadriceps tendon femoral ligaments [MQTFL]). The multiple risk factors for recurrent patellar instability include the two of which Feller discussed: trochlear dysplasia and patellar alta. Obviously, there are many additional risk factors that are outside the scope of his discussion. Recently, these have been compressed by Hevesi and colleagues with their recurrent instability of the patella (RIP) score (www.mdcalc.com/recurrent-instability-patella-rip-score) to give patients and physicians an estimate of future patellar instability: Is any surgery warranted?
Focusing on trochlear dysplasia, the Dejour classification may be looked upon as describing a trochlear “groove” that is shallow, flat or convex. Liu and colleagues have published work demonstrating that a well-performed MPFL reconstruction without trochleoplasty in patients with shallow and flat “grooves” can achieve good stability outcomes. We submitted a comparison of 50 patellar instability patients with 50 stable patients and, in that series, only four were classified as Dejour C or D (convex). Thus, even in a practice that has a PF focus, convex trochleas that may have a trochleoplasty indication are not common. Furthermore, Bollier and Fulkerson have cautioned about the long-term implications of trochleoplasty on the articular cartilage citing reports of chondrosis. Note that even with his seasoned experience, Feller noted trochleoplasty is “technically demanding and certainly frightening.”
Thus, the decision to add trochleoplasty to one’s armamentarium should not be taken lightly. A first step might be to add the Peterson bumpectomy (removing only the supratrochlear spur that Feller detailed) and then, if you truly want to treat these complex patients with convex trochleas, seek out a surgeon with extensive experience to directly learn the technique rather than embarking after reading technique materials.
References:
Bollier M, et al. J Am Acad Orthop Surg. 2011;19:8-16.
Daynes J, et al. J Knee Surg. 2016;29(6):471-7. doi: 10.1055/s-0035-1564732.
Hevesi M, et al. Arthroscopy. 2019;doi:10.1016/j.arthro.2018.09.017.
Liu JN, et al. Am J Sports Med. 2018;doi:10.1177/0363546517745625
Peterson L, et al. Bull Hosp Jt Dis Orthop Inst. 1988;48:130-139.
OrthoIndy Center for Joint Preservation, Cartilage Regeneration and OrthoBiologics/Regenerative Medicine
Patellofemoral Subsection