Issue: April 2021
Source: Everhart JS, et al. Arthroscopy. 2017;doi:10.1016/j.arthro.2016.11.007.
Disclosures: Baria reports he receives research support from Arthrex and is a paid presenter for Terumo. Magnussen reports he is a board or committee member of the ACL Study Group, the American Orthopaedic Society for Sports Medicine and the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; is on the editorial or governing board of the Journal of the American Academy of Orthopaedic Surgeons and the Orthopaedic Journal of Sports Medicine; and receives research support from Zimmer Biomet and Smith & Nephew; and receives educational support from Arthrex. Durgam and Miller report no relevant financial disclosures.
April 19, 2021
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Ultrasound-guided percutaneous tenotomy is effective for patellar tendinosis

Issue: April 2021
Source: Everhart JS, et al. Arthroscopy. 2017;doi:10.1016/j.arthro.2016.11.007.
Disclosures: Baria reports he receives research support from Arthrex and is a paid presenter for Terumo. Magnussen reports he is a board or committee member of the ACL Study Group, the American Orthopaedic Society for Sports Medicine and the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine; is on the editorial or governing board of the Journal of the American Academy of Orthopaedic Surgeons and the Orthopaedic Journal of Sports Medicine; and receives research support from Zimmer Biomet and Smith & Nephew; and receives educational support from Arthrex. Durgam and Miller report no relevant financial disclosures.
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Patellar tendinosis is a frustrating condition commonly encountered in athletes who place high loads on the extensor mechanism of the knee — particularly during jumping or running.

Noninvasive treatments include load modification, rehabilitation and shockwave therapy. Injections, such as platelet-rich plasma (PRP) and sclerosants, can also be effective, but can require a series of treatments that may take several months before significant improvement is noticed. If a patient fails to improve, surgery may provide further symptom relief. The two most common approaches are open and arthroscopic debridement and there is no consensus on which method is superior.

tip of PUT device
1. The tip of the PUT device is shown.

Source: Michael R. Baria, MD, MBA

A minimally invasive method of tendon debridement referred to as percutaneous ultrasonic tenotomy (PUT) was introduced in 2011. Using ultrasound guidance, the device tip is inserted into the diseased tendon. The tip then oscillates to emit ultrasonic energy and simultaneously irrigates the tendon with sterile saline (Figure 1). Theoretically, this treatment debrides the tendinopathic lesion, but, prior to our work, this mechanism had not been definitively proven. It was unclear whether the device truly removed tendinopathic tissue or if it only fenestrated the tendon, which could still possibly lead to symptom improvement. As the patellar tendon is subjected to significant stress in high load athletes, we sought to define the exact effect of PUT on tendon structure so we could safely return athletes to training and competition as efficiently as possible after the procedure.

Debridement technique

The knee is placed into 20° flexion and prepped in the usual sterile fashion. The patient is sedated with IV propofol and local anesthesia is obtained by injecting 5 mL of 1% lidocaine both anterior and posterior to the patellar tendon under ultrasound guidance. The diseased portion of the tendon is localized with ultrasound and an 11-blade scalpel is used to incise the skin and fascia. Using ultrasound, the PUT device is guided to the tendinopathic lesion parallel to tendon fiber orientation. Ultrasonic energy is then turned on for 1 to 2 minutes as the device tip is moved in an oscillating fashion, taking care to make contact with only diseased tissue. Once the tendinopathic region has been treated, 1% ropivacaine is injected in a peritendinous fashion for post-procedure pain control. After the device is removed, the incision is covered with an adhesive bandage and waterproof dressing. After the procedure, patients undergo supervised rehabilitation with a milestone-based rehabilitation progression (Table).

Cadaveric study results

To determine the effect of PUT on tendon structure, the procedure was performed on four cadaveric tendons (two quadriceps and two patellar tendons), followed by cross-sectional histologic analysis. All four tendons demonstrated clear debridement of the target treatment area without any injury to the surrounding tissue outside of the debridement zone (Figures 2 and 3).

longitudinal section of the patellar tendon
2. A longitudinal section of the patellar tendon with a central area of debridement is shown.
cross section of the quadriceps tendon
3. A cross section of the quadriceps tendon is shown with the target area of debridement highlighted.

Clinical experience

PUT has been a useful addition to our clinical practice. It has proven safe with no infection or tendon rupture noted as patients have progressed through their rehabilitation. An informal analysis of our patient-reported outcomes with VISA-P demonstrated that the minimal clinically important difference threshold was crossed at an average of 6 months after the procedure, at which time the VISA-P score improved by about 30 points. Despite this improvement, some patients remained dissatisfied with their symptoms and requested additional treatments, including PRP injections and open surgical debridement.

Discussion

Patellar tendinosis is a challenging condition to treat, especially in the high load athlete. Conservative measures often are unable to fully treat the patient’s symptoms, prompting surgical debridement. PUT offers an attractive approach to debridement. In our cadaveric work, we demonstrated that PUT results in a true debridement, not just tendon fenestration. In clinical practice, the procedure has proven to be safe in a small number of patients and it can help alleviate pain. However, symptomatic improvement still takes about 6 months and some patients remain dissatisfied despite experiencing clinical improvement. These results speak to the difficulty of treating patellar tendinosis in an athletic population.

One potential explanation of the persistence of symptoms in some cases is the fact that patellar tendinosis typically involves more structures than the tendon itself. In some cases, the disease process may involve the patella, Hoffa’s fat pad and the paratenon. The PUT device is only able to address tendon pathology; this limitation may be an explanation for the longer recovery time and persistent symptoms in our population. A newer iteration of the device is designed to address both tendon and osteophytes, but further research is needed to determine if this technical advancement results in improved outcomes.