Chronic tendinopathy , or tendinosis, refractory to conservative management may be an indication for surgical treatment. Surgical tenotomy , which involves the division of a tendon, aims to remove fibrotic and degenerative tissue in hopes of improving blood flow to promote an active healing environment [1]. While these techniques have historically been effective, invasive surgical intervention can lead to a multitude of complications including wound infections, skin necrosis, scar formation, and even tendon rupture, in addition to a prolonged recovery period [2]. Less invasive approaches, with the goal of reducing recovery periods and improving safety have more recently been studied with promising outcomes. In addition, patients undergoing percutaneous intervention have been shown to have therapeutic benefits earlier in the postprocedural period than those treated with an open procedure [3].

Percutaneous Needle Tenotomy (PNT) , also known as tendon needling or tendon fenestration, involves creating multiple small perforations within the chronic affected tendon. This is in contrast to traditional surgical tenotomy or release, in which tendons are cut. The goal of tendon fenestration is to shift a chronic degenerative injury into an acute process. Increased localized bleeding releases growth factors activating fibroblasts, which induce collagen formation. This process helps to promote tendon healing and pain relief.

Another percutaneous treatment for chronic tendinopathy , which has more recently been studied in the literature, is the Tenex Health TX procedure (Tenex Health, Lake Forest, California). This novel device, which has been approved by the U.S. Food and Drug Administration, is also referred to in the literature as “fasciotomy and surgical tenotomy ,” or FAST [4]. Tenex Health TX is a procedure which involves the utilization of ultrasonic energy, delivered by the TX1 device through low-amplitude high-frequency oscillations, directed at diseased tendon tissue under ultrasound guidance [5]. The theory behind the Tenex Health TX procedure is based on the phacoemulsification more commonly used to treat cataracts. Tenex Health TX , similar to percutaneous needle tenotomy, aims to remove degenerative tendon tissue to stimulate an active healing process. However, in contrast to needle tenotomy, the TX1 device actually has little effect on normal collagen and tissue, instead microresecting only pathological scar tissue within the tendon [6].

First-line treatment for tendinopathy remains conservative nonoperative management with activity modification, physical therapy, NSAIDs, and eccentric exercises. Additionally, bracing and corticosteroid injections may provide symptom relief in some patients. Both needle tenotomy and the Tenex Health TX procedure may be appropriate for patients with approximately 6 months of symptoms refractory to conservative management. In the studies assessing for therapeutic benefits with these minimally invasive procedures, patients generally had symptoms for greater than 6 months that interfered with their ability to function and were progressively worsening [5, 6]. Although, this time frame is not a requirement, as a few studies utilized patients with symptoms for greater than 3 months, rather than 6 months [7–9].

The diagnostic utility of ultrasound has become more popular in recent years. Ultrasound guidance allows for direct visualization of diseased tendons and ensures greater accuracy for treatment during a percutaneous approach. The reliability of ultrasound to diagnose tendinous injuries is well documented, with one study finding an equal sensitivity and specificity to that of MRI in the case of patellar tendinopathy [6]. Given that chronic tendinopathy is a result of a failed healing process with degenerative changes rather than a true inflammatory process, certain tendon characteristics are evident with ultrasound. Studies have described the sonographic assessment of tendons prior to percutaneous treatments with four features, which include the following: tendon size, tendon echotexture, interstitial tendon tears, and neovascularity [10].

Tendon size is usually increased with chronic tendinopathy . Hypoechoic areas within the tendon, as well as interstitial tears, indicate collagenous disruption. Additionally, tendon hypervascularity is thought to correlate with symptoms. These findings on ultrasound examination support the diagnosis of tendinopathy and can additionally be monitored posttreatment

No standardized protocol for the treatment of tendinopathy with needle tenotomy or fenestration has been identified in the literature. In fact, even the use of ultrasound to visualize tendon fenestration is not considered a requirement, although this may bring into question the accuracy of tendon needling [8]. A large majority of the studies available for review did utilize ultrasound for tendon visualization. The advantage of a percutaneous approach compared to open surgery is that patients may be treated in an office-based ambulatory setting, as opposed to the operating room. Additionally, complications associated with general anesthesia can be avoided as only local anesthetic treatment is required.

After patient screening and selection, a preprocedural ultrasound assessment is usually performed to identify the areas of tendinopathy. With patient agreement and consent, the percutaneous tenotomy can even be performed the same day as the ultrasound assessment. Patients are placed in correct positioning and a sterile field is created. Probe covers are used for the ultrasound machine to ensure sterility. Using ultrasound guidance, the patient is injected with a local anesthetic for pain control in the procedural area. Most often, the ultrasound probe is placed longitudinally near the tendon insertion site for an in-plane approach [7]. A variety of needle sizes have been described for actual tendon fenestration. One study, in which patients with elbow tendinopathy were treated , utilized a 16-gauge needle for fenestration [9]. Other studies used hypodermic needles between 18-gauge and 25-gauge [7, 11, 12]. There are currently no studies available comparing the therapeutic effects of different needle sizes or different methods for actual tendon fenestration. Once the procedure is completed, hemostasis is achieved with manual pressure and patients only require a simple dressing.