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.

Diagnosis and treatment of patellofemoral disorders must be individualized

After reading an article from Pagenstert and colleagues on lateral retinacular release vs. lengthening, I was compelled to respond with a letter to the editor. I was surprised and disappointed that an orthopedic surgeon would design a study using a 22-year-old technique that was said to assure an “adequate” release (the “90° turn-up” test), even cutting the vastus lateralis tendon if necessary to achieve this goal, and leave it unrepaired. Severing the vastus lateralis tendon is known to cause iatrogenic medial patellar subluxation and permanent disability in a high proportion of patients. Indeed, about one third of their release-only patients have this totally predictable fate.

Permanent harm

In the authors’ reply to my letter, I was relieved to learn that they were ignorant of the permanent harm and disability their study would cause to the release-only cohort. However, I was disappointed to find out they had based their rigid adherence to the 90° turn-up test only on a diagram in a chapter of a 2008 textbook. Apparently, they had neither read nor heeded the advice within the text of that very same chapter, which reads, “The proximal release is not extended into the muscle fibers of the vastus lateralis or quadriceps tendon.”

 

Alan C. Merchant

Furthermore, they said there was no information available in international publications warning about over-release by cutting the vastus lateralis tendon. Yet a cursory search of Medline revealed several articles containing this information predating 2008. For the sake of brevity, I only cite a 1995 study article by Marumoto and colleagues published in the American Journal of Sports Medicine.

Many members of the International Patellofemoral Study Group encouraged me to write this review to:

  • Clarify the indications for a lateral retinacular release (LRR);
  • Explain a satisfactory LRR; and
  • Avoid the damage caused by over-release.

I consider these issues logically simple. After proper nonoperative treatment has failed and a tight lateral retinaculum (LR) is the cause of symptoms, then a LRR is logical. Even if it is not the only cause of symptoms, it is a logical first step. If the LR is not tight, then don’t release it. A satisfactory LRR should not cut the muscle or tendon of the vastus lateralis. Remembering that the goal of a LRR is to normalize a tight LR, then a reasonable endpoint is a medial glide test of more than one quadrant, or more than one fingerbreadth. Another reasonable endpoint is a 60° tilt-up test. It is safe to release the LR distally to the joint line if necessary to achieve these endpoints.

Individualized diagnosis and treatment

The diagnosis and treatment of all patellofemoral disorders must be individualized. To quote Scott F. Dye, MD, It is an “intellectually and clinically constrained notion that a single, simple, structural, surgical ‘90° turn-up test – one size fits all approach’ works in a system as complex as the living human knee.” By individualizing treatment, the LRR also can achieve satisfactory results in approximately 60% of patients with isolated patellofemoral osteoarthritis. Likewise, in certain patients with recurrent patellar dislocation, a LRR can achieve excellent long-term results.

Finally, the fault for the publication of the Pagenstert and colleagues study does not lie solely with the authors. Institutional review boards were established to avoid causing permanent harm to patients during clinical studies, yet this study was allowed. In addition, there is another factor at work – the tyranny of evidence-based medicine. Journal editors and their appointed reviewers seem so eager to publish prospective double-blinded comparative studies having higher levels of evidence that clinical judgment, experience and historical perspective are forgotten. This is not a new idea. Others have noticed this intrusion of evidence-based clinical guidelines and protocols, including Latov and Hieb.

I thank Healio.com for helping to widen the audience for this discussion and the members of International Patellofemoral Study Group and the Patellofemoral Foundation for their encouragement and support.

References:

Gasser S. Arthroscopic lateral release of the patella with radiofrequency ablation. In: Jackson DW, ed. Master Techniques in Orthopaedic Surgery: Reconstructive Knee Surgery. 3rd ed. Philadelphia: Lippincott, Williams & Wilkins; 2008;1-11.

Hieb LD. Why your doctor is out of date. Journal of American Physicians and Surgeons. 2005;10(1):69-70. Available online at: www.jpands.org/vol16no3/hieb.pdf

Latov N. Evidence-based guidelines: Not recommended. Journal of American Physicians and Surgeons. 2005;10(1):18-19. Available online at: www.jpands.org/vol10no1/latov.pdf.

Marumoto JM. A biomechanical comparison of lateral retinacular releases. Am J Sports Med. 1995;23(2):151-155.

Merchant AC. Arthroscopy. 2013;doi:10.1016/j.arthro.2013.01.002.

Pagenstert G. Arthroscopy. 2012;doi:10.1016/j.arthro.2011.11.004.

Pagenstert G. Arthroscopy. 2013;doi:10.1016/j.arthro.2013.01.001.

  • Alan C. Merchant, MD, is a clinical professor, Emeritus Medical Staff, Department of Orthopedic Surgery, Stanford University School of Medicine, Stanford, Calif., and Emeritus Medical Staff, Department of Orthopedic Surgery, El Camino Hospital, Mountain View, Calif.
  • Disclosure: Merchant has no relevant financial disclosures.

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