TenJet Procedure for Chronic Tendon Pain: Remove It, Don’t Jam It

Chronic tendon pain is usually filed under the wrong word. Tendinitis implies an inflamed tendon that rest and anti-inflammatories will calm, and when they do not, the offer escalates to a steroid shot and sometimes a nerve stimulator. The TenJet [high-pressure saline-jet tendon resection device] procedure starts from a different premise: the painful part of a chronic tendon is damaged tissue that can be removed. That argument runs through Chapter 14 of The Pained Brain, the video above, by Dr. Gurpreet Singh Padda, MD, MBA, MHP, and Dr. KrisJay Fucanan, MD.

Tendinosis vs tendinitis: what the tissue actually shows

When pathologists examined chronically painful Achilles, patellar, elbow and rotator cuff tendons, they found broken, disorganized collagen, swollen ground substance, tendon cells turned plump and cartilage-like, and new capillaries threading through the lesion. The feature they called most significant was an absence: no inflammatory cells. Later biopsies refined that without reversing it. Immune cells are present, but in a chronic, non-resolving pattern rather than an acute flare. It is a failed repair with a low fire that never goes out. A small microdialysis study agrees: glutamate, a pain-signaling chemical, ran about four times higher inside painful Achilles tendons than in controls, while prostaglandin E2, a marker of classic inflammation, did not differ.

What makes the lesion hurt is what grows into it. Doppler ultrasound found new vessels in 28 of 28 painful Achilles tendons and none of 20 normal ones, with pain-carrying nerve fibers running beside them. Yet across 141 tendons, the amount of vessel did not track the pain score. The vessels mark where the lesion is, not how much it hurts.

Why a chronic tendon does not heal on its own

Carbon-14 left in the air by bomb tests works as a clock, and in adult Achilles tendons the core collagen matched the atmosphere from a median of 8 years after birth. The core is built during growth and essentially never renewed. Among 174 patients with ultrasound-confirmed plantar fasciitis, 50.0 percent still had it at five years, and in greater trochanteric pain syndrome, 45.0 percent still had it eleven years later against 5.3 percent of controls.

In the placebo-controlled tennis elbow trial, one-year recurrence was 54 percent after steroid against 12 percent after a placebo injection. What that loan costs the tissue is laid out in what a cortisone shot costs the joint over time.

What a peripheral nerve stimulator does, and does not do

For some patients a stimulator is the right tool. Its theory is that input from large, non-pain fibers closes a gate on pain signals in the spinal cord, and the most complete modern review still calls the exact mechanism largely unknown. Nothing in that literature describes tendon repair. Stimulation modulates a signal.

The randomized record shows real responders and a large expectation effect. In the pivotal implanted peripheral trial, 38 percent responded at three months against 10 percent on the control setting. In a blinded spinal cord stimulation crossover, the sham setting reduced pain 34 percent, matching two of three active settings. In the FDA device-report database, 43.8 percent of reported peripheral stimulator events ended in explantation, a share of reports rather than an incidence rate, and at one center 28 percent of implanted patients later needed an MRI, most of the scans for something unrelated to the device. No randomized trial has tested a nerve stimulator on a tendon lesion. What a spinal cord stimulator trial can and cannot tell you is worth reading before any implant.

How the TenJet procedure works and what its record shows

The device is a 12-gauge needle that sends sterile saline at pressures up to 14,000 psi across a small window near its tip, with suction pulling loosened tissue back up the needle. Healthy tendon is dense and resists the stream. Degenerated tissue is soft and mucoid, and in a bench model the jet removed it with negligible disruption of the healthy tissue around it. Ultrasound shows the gray lesion shrinking.

The published record is young and should be stated at its true strength. In a manufacturer-sponsored series of 32 elbows, pain fell from 5.1 to 0.5 at twelve months, though most of those patients received conscious sedation. In a 100-patient series under local anesthesia, the Oxford Elbow Score rose from a median of 23.5 to 45 at one year, and none of the 100 needed open release; baseline ultrasound severity did not predict who improved. The older ultrasonic cousin holds its gains longest: in the original cohort of 20 patients followed to 90 months, hypervascularity stayed resolved in 79 percent with no recurrence. In gluteal tendons, 29 patients went from a pain score of 5.86 to 2.82 at a mean of 22 months, and 3 went on to open repair.

The limits are real. The systematic reviews grade this body of evidence Level 4: before-and-after series, with no sham-controlled trial of tissue removal. In one survey after percutaneous tenotomy, median time to significant recovery was 58 days, and 26.1 percent of patients were not satisfied. Our practice performs the procedure awake under local anesthetic, without sedation, and patients drive home.

Why open surgery comes last for a tendon

When degenerated tissue at the tennis elbow was cut out in one group and the skin was simply opened and closed in the other, a blinded trial found no difference at any stage, and its authors estimated that more than 6,500 patients per group would be needed to show one. What open surgery reliably adds is recovery time and wound risk: in 432 consecutive open Achilles operations, 11 percent had a complication. Percutaneous removal takes the same tissue out through a needle and leaves surgery for last.

Loading and the metabolic terrain decide the result

A tendon rebuilds in response to force. Its cells sense load and answer with new collagen, a process called mechanotransduction, so resting a chronic tendon indefinitely withholds the signal that repairs it. In one post-procedure series, physical therapy accounted for 60 percent of the drop in elbow pain. In a gluteal tendinopathy trial, education plus a loading program beat a steroid injection by 20.4 percent at one year, with a number needed to treat of 4.9. Pooled data favor added external load over body weight alone, and loading less than daily over daily loading.

The load lands on a terrain. People with Achilles tendinopathy carried higher triglycerides and lower HDL than controls matched for body mass index, the lipid pattern of insulin resistance. In a Danish cohort, a hemoglobin A1c above 5.7 percent carried roughly three times the risk of a lower-limb tendon injury, and fluoroquinolone antibiotics raise the odds of Achilles tendinitis 3.95-fold. Patients with metabolic syndrome who did the same eccentric program as matched controls kept more pain and used more pain medication. The system adds its own drag: a procedure is a billable event, while the months of coached loading that decide the outcome often go unplanned, and only 44 percent of published tenotomy protocols prescribed structured rehabilitation. How high blood sugar stiffens tendons and nerve tunnels explains the chemistry.

What to ask before any tendon procedure

Ask whether anyone has imaged the tissue where you actually hurt. Ask for your hemoglobin A1c as a number and your triglyceride-to-HDL ratio, because not diabetic is not the same as a safe tendon. Bring your medication list and work any change through your physician. If a stimulator is proposed, ask for its responder rate and the MRI plan. If a resection is proposed, ask who writes the loading program and when it starts. Lateral hip pain deserves a direct look, since lateral hip pain is rarely just bursitis, and needle accuracy is the step before all of it, covered in why a blind needle misses its target. Every study behind these numbers is in the Technical Supplement to Chapter 14, with what each one does and does not show.

Frequently asked questions

What is the TenJet procedure?

It is a percutaneous tenotomy. Through a small skin nick and under ultrasound, a 12-gauge needle sends a fine saline jet that loosens soft, degenerated tendon tissue and suctions it out, while dense healthy tendon resists the stream. It is used for chronic elbow, hip and other tendon lesions after conservative care has failed, and a loading program follows. Pain down the side of the leg is not always the spine, as hip-related leg pain shows.

What is the difference between tendinosis and tendinitis?

Tendinitis means an inflamed tendon. Tendinosis describes what chronic tendon pain usually is under the microscope: disorganized collagen, cartilage-like cells, new vessels and nerves, and few classic inflammatory cells, with a smoldering unresolved inflammation inside that failed repair. The distinction matters because rest and anti-inflammatories aim at inflammation, while a degenerated tendon needs load and sometimes removal of damaged tissue. The exercise evidence for rotator cuff shoulder pain applies the same principle.

How long does recovery take after percutaneous tenotomy?

Expect weeks to months, not days. In one patient survey, median time to significant recovery was 58 days, and about one in four patients were not satisfied. A 100-patient elbow series used a wrist brace for 7 to 10 days and began physical therapy around day 14. In another series, most of the improvement came from the rehabilitation that followed the procedure. Heel pain that is not plantar fasciitis shows why the tissue is identified before any procedure.

Does a peripheral nerve stimulator help tendon pain?

No randomized trial has tested one for a tendon lesion such as tennis elbow, plantar fasciitis or gluteal tendinopathy. The nearest evidence, electroacupuncture at the elbow, showed no effect different from zero. Stimulators modulate pain signals and help a minority of patients with nerve-origin pain, but nothing in their described mechanism repairs tendon tissue. Here is what a 60-day nerve stimulator is actually testing.

Can a steroid injection make tendon pain worse over time?

In tennis elbow, the pattern points that way. Across 41 trials, corticosteroid gave a large short-term benefit that turned negative at intermediate and long-term follow-up, and in a placebo-controlled trial one-year recurrence was 54 percent after steroid against 12 percent after placebo. Serious harms were rare, with one tendon rupture among 991 participants. The problem is the reversal. Why each injection tends to buy less time than the last is covered here.

Sources

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Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP, board certified in anesthesiology, pain medicine, interventional pain management, addiction medicine and obesity medicine. Adapted from Chapter 14 of The Pained Brain by Dr. Padda and Dr. KrisJay Fucanan, MD. Last reviewed September 2026.

Dr. Gurpreet Singh Padda, MD, MBA, MHP