Rotator cuff tears are arguably the defining musculoskeletal complaint of middle age. The supraspinatus, the tendon that runs over the top of the shoulder and helps lift the arm away from the body, is the structure most frequently involved. Population studies cited in the report indicate that around twenty percent of people in their sixties carry a rotator cuff tear, a figure that climbs past fifty percent by the eighties. Complete tears often end in the operating theater, but partial-thickness tears occupy an uncomfortable middle ground: there is no consensus on the optimal management strategy, and conventional conservative treatments, including rest, physical therapy, non-steroidal anti-inflammatory drugs, and corticosteroid injections, leave a substantial share of patients with persistent pain and functional limitation. Studies referenced by the authors suggest that up to forty percent of patients fare poorly with these standard approaches, and corticosteroid injections, while offering short-term relief, have been linked in the literature to potential detrimental effects on tendon healing and structural integrity.

The patient at the center of the report was, in many respects, the archetype of this treatment-resistant group. A right-hand-dominant nurse, she had endured twenty-four months of left shoulder pain, on her non-dominant side, driven in part by the repetitive overhead reaching, lifting, and patient-transfer demands of her profession. Her baseline magnetic resonance imaging confirmed a nine-millimeter partial-thickness, articular-sided tear of the supraspinatus tendon, with the remainder of the shoulder unremarkable: no significant bursal thickening, a normal biceps tendon, and an intact acromioclavicular joint. Before electroacupuncture was considered, she had already failed an extensive conservative program, including twelve weeks of structured physiotherapy with ultrasound therapy, manual therapy, and rotator cuff strengthening, six weeks of twice-daily oral diclofenac, and two subacromial injections of methylprednisolone administered two months apart. She was selected retrospectively from routine clinical practice because she met predefined criteria, including complete adherence to treatment and comprehensive clinical and imaging follow-up, and she provided written informed consent for both treatment and publication.

The intervention itself combined a twelve-session electroacupuncture protocol with a daily home exercise program, and the technical details are what give the report its scientific texture. An expert physiotherapist trained in acupuncture inserted single-use stainless steel needles, 0.25 millimeters in diameter and 30 millimeters long, at four shoulder points: Large Intestine 16, Triple Burner 14, Small Intestine 10, and an Ashi point at the tip of the coracoid process, which corresponds anatomically to the region of the supraspinatus insertion and was chosen for focal stimulation. The point selection followed traditional meridian theory and previously published protocols for shoulder disorders, with LI-16 and TB-14 serving as local points and SI-10 as an adjacent one. Electrodes connected LI-16 and TB-14 together, and SI-10 to the coracoid-tip point, delivering a symmetric biphasic pulsed current at a fixed frequency of 5 hertz for twenty minutes per session, with sessions twice weekly.

Current intensity, capped at five milliamperes, was titrated individually to produce a strong but comfortable, non-painful paresthesia, the sensation known in traditional practice as De-Qi, without triggering forceful muscle contractions. Safety considerations were explicit: because the shoulder points lie near the thorax, needle angle and depth at LI-16 and TB-14 were carefully controlled to avoid pleural puncture, and needles were never oriented transversely toward the rib cage. Alongside the needling, the patient followed a phased home program: pendulum exercises and passive range-of-motion work with a cane or pulley in the first two weeks; scapular retraction, isometric holds, and elastic-band rotation exercises from weeks three to six; and a maintenance regimen of strengthening three to four times weekly thereafter. She documented adherence above ninety percent during the active treatment phase, modified her work duties temporarily, and received no oral analgesics, anti-inflammatories, or injections during the treatment period, a detail that strengthens the temporal association between the intervention and her recovery.

The outcomes were striking by any measure. Pain on the numeric rating scale fell from eight out of ten at baseline to three out of ten at week six, and to zero at the six-month follow-up, a one hundred percent reduction. The Disabilities of the Arm, Shoulder and Hand questionnaire score improved from 72.5 to 28.3 at week six and 12.3 at six months, an overall eighty-three percent improvement that far exceeds the established minimal clinically important difference of 10.8 points for shoulder disorders. Range of motion improved across every plane tested: active abduction rose from 95 to 160 degrees by week six and 175 degrees at six months, flexion from 100 to 180 degrees, and external rotation from 25 to 60 degrees. She returned to full work duties by the three-month occupational review, achieving precisely the goals she had set for herself: pain-free work and avoidance of surgery.

The most provocative finding, however, was structural. A repeat magnetic resonance scan at six months, acquired with identical imaging parameters on the same 1.5-Tesla scanner, using oblique coronal T2-weighted fat-suppressed fast spin-echo sequences with 3.5-millimeter slice thickness, showed an estimated reduction in tear dimensions from nine millimeters to approximately four millimeters in the oblique coronal plane. The reviewing shoulder-fellowship-trained orthopedic surgeon also noted a qualitative reduction in T2 signal hyperintensity within the tendon, potentially consistent with decreased tendinosis, although the authors emphasize that signal intensity was assessed descriptively and not normalized to a reference tissue. No progression of the tear or new pathology was identified, and the patient reported no adverse effects beyond mild, transient soreness at the needle sites after the first two sessions, which resolved within twenty-four hours.

The authors are candid about the caveats, and they are substantial. Measurement of partial-thickness tears is inherently variable, depending on slice selection, sequence parameters, and reader interpretation, and the reviewing surgeon was not blinded to the time point. More fundamentally, the concurrent home exercise program is the report’s most significant confounder: because electroacupuncture and exercise were delivered as a multimodal package, it is impossible to isolate the specific effect of either component. The improvements may reflect synergy, or they may have been driven primarily by the rehabilitative exercises, with electroacupuncture providing adjunctive pain relief that facilitated adherence. Natural healing, placebo effects, and regression to the mean all remain possible in an uncontrolled single-patient design, and the specific protocol, including point selection, frequency, and treatment dose, has not been systematically optimized.

Nevertheless, the case gains plausibility from a growing body of mechanistic work on electroacupuncture and tendon biology. In a rat model of Achilles tendon rupture, researchers found that electroacupuncture increased fibroblast proliferation, collagen synthesis, and the mechanical strength of healing tendons. Separate animal work on rotator cuff injury reported reduced levels of the inflammatory cytokines interleukin-1 beta and tumor necrosis factor alpha, alongside increased anti-inflammatory interleukin-10, potentially creating a more favorable environment for repair. Other studies have shown that electroacupuncture modulates matrix metalloproteinase activity, enhancing extracellular matrix remodeling, and that electrical stimulation more broadly promotes cellular migration, local blood flow, and growth factor production in connective tissue. The 5-hertz frequency used in this case aligns with research suggesting that low-frequency stimulation optimally triggers endorphin and growth factor release relevant to tissue repair.

Where the case fits into the broader evidence base remains an open question. Prior trials of acupuncture for shoulder pain have generally addressed mixed etiologies rather than imaging-confirmed rotator cuff tears, though meta-analytic evidence suggests acupuncture adds benefit to exercise-based physical therapy compared with exercise alone, and conventional non-operative care for small supraspinatus tears typically yields satisfactory outcomes in roughly seventy-five percent of patients, but over three to six months and with residual symptoms common. The authors call for randomized controlled trials comparing electroacupuncture against standard conservative care and sham acupuncture, incorporating both clinical and imaging endpoints, exploring dose-response relationships, and correlating biomarkers of tissue healing with outcomes to identify likely responders. Until such studies exist, this single nurse’s recovery, from eight-out-of-ten pain and a nine-millimeter tear to zero pain and a four-millimeter residual defect, stands as an intriguing, rigorously documented hypothesis generator rather than a practice-changing result, and a reminder that even ancient techniques can still surprise modern imaging.

Subject of Research: Electroacupuncture treatment of partial-thickness supraspinatus tendon tears

Article Title: Therapeutic Effects of Electroacupuncture on Partial‐Thickness Supraspinatus Tear: Clinical Case Report

Article References: Hajvalie, G., Takamjani, I. E., Sarrafzadeh, J., Saremi, H., & Asadi, M. R. (2026). Therapeutic Effects of Electroacupuncture on Partial‐Thickness Supraspinatus Tear: Clinical Case Report. Clinical Case Reports, 14(10), Article e73685. https://doi.org/10.1002/ccr3.73685

Image Credits: AI Generated

DOI: 10.1002/ccr3.73685

Keywords: electroacupuncture, supraspinatus tear, rotator cuff, shoulder pain, tendon healing, MRI, case report, physical therapy, DASH score, regenerative medicine, musculoskeletal disorders, Therapeutic

Tendon-bone insertion injuries, which occur where soft tendon tissue anchors into hard bone, are among the most frequently encountered injuries in daily life and sports. Their clinical burden is growing annually, and restoring normal physiological function remains remarkably difficult. The reason lies in the anatomy: the tendon-bone junction is a graded transition zone that includes a specialized fibrocartilage layer, and unlike many tissues, it cannot regenerate itself faithfully after injury. Instead, the body fills the gap with disorganized scar tissue that has low biomechanical strength. That weakness translates directly into high postoperative re-rupture rates, making rapid, high-quality regeneration an urgent challenge in orthopedics, sports medicine, and tissue engineering.

The quality of tendon-bone healing depends heavily on how well the fibrocartilage layer regenerates at the interface, and macrophages, the versatile immune cells that flood any wound site, orchestrate much of that process. In the early phase of healing, M1-polarized macrophages dominate, secreting pro-inflammatory factors such as IL-1β and IL-6 that intensify local inflammation and recruit fibroblasts to the damaged site. Later, macrophages shift toward the M2 phenotype, releasing anti-inflammatory signals like IL-10 and Arg1 that dampen inflammation and promote tissue reconstruction. Previous work has shown that this transition from a pro-inflammatory to an anti-inflammatory microenvironment is crucial for moving from the inflammatory phase into the proliferative phase of repair, and that biologically inducing early M2 aggregation at the interface actively improves healing outcomes.

What makes the new study distinctive is its focus on macrophage metabolism. M2 macrophages rely on oxidative phosphorylation and fatty acid oxidation (FAO) for their energy supply, whereas activation of PPAR signaling and its regulatory genes increases FAO capacity. The research team, led by Xiaojun Ma and colleagues, hypothesized that if a compound could push macrophage metabolism toward FAO and oxidative phosphorylation, it would favor M2 polarization and thereby improve tendon-bone healing. Didymin was a natural candidate: earlier reports had documented its purgative, anti-inflammatory, and antioxidant properties, and prior metabolic tracing experiments had revealed that the compound enhances FAO rather than glycolysis. Crucially, didymin had already been shown to modulate the M1/M2 balance by converting pro-inflammatory M1-like macrophages into anti-inflammatory M2-like ones, without altering baseline M2 polarization.

To test the hypothesis, the researchers established a mouse model of tendon-bone healing by surgically severing the Achilles tendon near the calcaneal bone, scraping away the residual fibrocartilaginous layer, drilling a bone channel, and suturing the tendon stump back to the bone, a procedure that mimics the changes seen after rotator cuff reconstruction. Thirty-six male C57BL/6J mice were randomly assigned to six groups: a sham-operated control, an untreated model group, three didymin dose groups receiving 1, 2, or 4 milligrams per kilogram per day by oral gavage, and a positive-control group receiving the drug disulfiram at 50 milligrams per kilogram per day. Treatment began one day after surgery and continued daily for four weeks, with all protocols approved by the animal ethics committee of the People’s Hospital of Ningxia Hui Autonomous Region.

The structural results were striking. Micro-computed tomography scanning showed that high-dose didymin produced new bone volume at the interface comparable to that seen in the positive-control group, with significant increases in bone volume fraction, bone surface, trabecular number, and bone mineral density, along with significantly reduced trabecular separation compared with the untreated model group. Histological staining revealed that model-group animals suffered from disorganized collagen fibers, consolidated fibroblast nuclei, necrotic areas, and inflammatory cell infiltration at the junction, all of which were attenuated by didymin treatment. Serum biochemistry told a matching story: levels of osteocalcin, alkaline phosphatase, and calcium, all markers of bone formation activity, rose significantly in the treated animals.

Fibrocartilage regeneration, the critical determinant of healing quality, also improved. Safranin-O/fast green staining showed localized absence of the cartilage layer and abnormal chondrocyte proliferation in untreated mice, defects that didymin largely corrected. Immunofluorescence assays demonstrated that expression of the cartilage markers Sox9 and Collagen II, which dropped sharply at the injured interface, was significantly restored by the compound. The researchers also measured increased expression of TGF-β1 and TGF-β3, growth factors known to drive chondrogenesis and fibrocartilage formation, further supporting the conclusion that didymin actively promotes regeneration of the specialized transition tissue rather than merely reducing inflammation.

Flow cytometry and molecular profiling of the healing tissue revealed the immune mechanism at work. Untreated model mice showed elevated levels of F4/80-positive CD86-positive M1 macrophages and elevated IL-1β and IL-6 mRNA, while didymin administration at all three doses reduced these pro-inflammatory indicators. Medium and high doses simultaneously raised the abundance of F4/80-positive CD206-positive M2 macrophages and increased expression of Arg1 and IL-10. In parallel cell experiments using bone marrow-derived macrophages, didymin significantly reduced CD86 expression under M1-polarizing conditions and boosted levels of acetyl-CoA, the FAO enzymes Cpt1a and ACS, and the PPAR pathway proteins PPAR-γ and RXRA, indicating a metabolic reprogramming toward fatty acid oxidation.

The team then ran a decisive validation experiment using pharmacological blockers. When the PPAR-γ antagonist GW9662 or the fatty acid oxidation inhibitor etomoxir was added to didymin-treated M1 macrophages, the compound’s effects were substantially reversed: acetyl-CoA levels, CD206-positive M2 populations, and anti-inflammatory Arg1 and IL-10 expression all fell, while CD86-positive M1 populations and pro-inflammatory IL-1β and IL-6 rose again. This loss-of-function evidence strongly suggests that didymin drives macrophage polarization toward the M2 phenotype specifically by promoting the PPAR signaling-mediated FAO pathway, which in turn supports tendon-bone healing.

The authors acknowledge important limitations that temper immediate clinical translation. No biomechanical testing was performed, the antagonist and inhibitor experiments were conducted only in cell culture rather than in living animals, and all mice received local penicillin injections postoperatively, which could theoretically interact with didymin’s anti-inflammatory and antibacterial properties. Only male mice were studied, and sex is known to influence inflammatory responses, bone metabolism, and tendon healing, so verification in female animals is needed. The mouse Achilles model also cannot fully reproduce the biomechanics, vascular supply, and stress conditions of human rotator cuff attachment sites. Even so, the study lays a concrete foundation for didymin as a candidate therapy, linking a dietary flavonoid, immune cell metabolism, and musculoskeletal regeneration in a single mechanistic chain that future research can now build upon.

Subject of Research: The role of didymin in promoting tendon-bone healing through PPAR-mediated fatty acid oxidation and macrophage M2 polarization

Article Title: Didymin may Enhance Tendon‐Bone Healing Partly by Promoting PPAR‐Mediated Fatty Acid Oxidation and Macrophage M2 Polarization

Article References: Ma, X., Shen, J., Ma, J., Li, H., Li, Y., & Wan, J. (2026). Didymin may Enhance Tendon‐Bone Healing Partly by Promoting PPAR‐Mediated Fatty Acid Oxidation and Macrophage M2 Polarization. Immunity, Inflammation and Disease, 14(9), Article e70485. https://doi.org/10.1002/iid3.70485

Image Credits: AI Generated

DOI: 10.1002/iid3.70485

Keywords: didymin, tendon-bone healing, macrophage polarization, M2 macrophages, PPAR signaling, fatty acid oxidation, fibrocartilage, Achilles tendon, rotator cuff, bone regeneration, inflammation, natural compounds