Tendinopathy in Special Populations: What Changes, What Stays the Same

What Tendinopathy Actually Is (and Why Population Context Matters)

Tendinopathy describes a spectrum of failed tendon healing characterized by disorganized collagen, increased ground-substance deposition, and neovascularization without true inflammation in chronic stages. The Achilles, patellar, rotator cuff, and common extensor origin (lateral epicondyle) are the most commonly affected structures. Symptoms must persist beyond 3 months and align with characteristic exam findings before the diagnosis is confirmed; imaging via diagnostic ultrasound or MRI is added when clinical certainty is low.

Population context changes three variables: the baseline biology of the tendon, the acceptable intensity and duration of loading interventions, and the safety profile of adjunctive treatments. A 24-year-old competitive sprinter and a 68-year-old woman with type 2 diabetes may both present with insertional Achilles pain scoring 6/10 on the VISA-A questionnaire, yet their treatment timelines, load targets, and complication risks differ substantially.

The Pathology Common to All Groups

At the cellular level, tendinopathy involves a shift from type I collagen (high tensile strength) to type III collagen (weaker, more disorganized). Tenocytes lose their spindle morphology and adopt a rounded, fibrocartilaginous phenotype. This process is consistent across populations, though the rate of progression and the capacity for reversal vary with age, metabolic status, and mechanical exposure.

Diagnosis Across Populations

Diagnosis rests on three pillars regardless of population: localized tendon pain reproduced by palpation, pain with progressive loading (single-leg calf raise, resisted wrist extension, etc.), and a symptom duration exceeding 3 months. A 2018 systematic review in the British Journal of Sports Medicine confirmed that the Victorian Institute of Sport Assessment (VISA) family of patient-reported outcome measures provides reliable monitoring across Achilles (VISA-A), patellar (VISA-P), and shoulder (ROWE/VISA-equivalent) presentations.

Ultrasound findings of hypoechogenicity and neovascularization on Doppler support, but do not replace, clinical diagnosis. MRI is reserved for cases where partial or complete rupture must be excluded.

Tendinopathy in Elite and Recreational Athletes

Athletes develop tendinopathy when cumulative mechanical load exceeds the tendon's adaptive capacity. The pattern differs between sports: Achilles and patellar tendinopathy dominate in running and jumping athletes, while rotator cuff and lateral epicondyle tendinopathy are more common in overhead and racket sports.

Load Management as the Starting Point

Load management means reducing, not eliminating, mechanical stress. Complete rest produces tendon atrophy within days. A 2015 RCT by Beyer et al. (N=58) comparing heavy slow-resistance (HSR) exercise to eccentric-only training in Achilles tendinopathy found comparable VISA-A improvements at 12 weeks (HSR: +20.2 points; eccentric: +17.7 points), with greater patient satisfaction in the HSR group at 52-week follow-up. HSR involves bilateral or unilateral calf raises at 6 repetition-maximum loads, progressed every 2 weeks based on pain monitoring (pain allowed up to 5/10 on numeric rating scale during exercise, resolving within 24 hours).

Return-to-Sport Criteria

Clearing an athlete for full return before the tendon has adapted is the single most common cause of re-injury. Published criteria from the 2019 International Olympic Committee consensus include:

• VISA-A score above 80 for Achilles, VISA-P above 80 for patellar
• Single-leg heel-rise test at least 25 repetitions (Achilles) or pain-free single-leg squat to 60 degrees (patellar)
• Limb symmetry index above 90% on hop tests

Seasonal athletes often pressure clinicians to accelerate return. A 2020 systematic review (N=14 studies, 1,062 athletes) found that failure to meet functional criteria before return-to-sport was associated with a 3.4-fold increase in re-injury within 6 months.

Corticosteroid Injections in Athletes

Corticosteroids reduce short-term pain but carry a documented risk of collagen necrosis and tendon rupture with repeated injections. A 2010 RCT by Coombes et al. demonstrated that a single corticosteroid injection produced superior short-term pain relief at 4 weeks but significantly worse outcomes at 52 weeks compared to physiotherapy alone in lateral epicondylalgia. In athletes, corticosteroid injections should be limited to one injection per tendon per year and paired with a structured loading program.

Tendinopathy in Older Adults (Age 60 and Above)

Older adults present a distinct biological environment. Tenocyte density declines with age, collagen synthesis slows, and vascularity within the tendon proper decreases. These changes mean that the same cumulative load that a 30-year-old adapts to within 8 weeks may take 16-24 weeks to produce comparable adaptation in a 65-year-old.

Adjusting Load Progression

The Silbernagel combined loading program, validated originally in younger cohorts, has been adapted for older adults by reducing weekly load increments to 10% instead of the standard 20% and extending the total program from 12 to 20 weeks. A 2018 cohort study (N=46, mean age 64 years) using this modified protocol reported a mean VISA-A improvement of 23 points at 20 weeks, comparable to outcomes seen in younger populations on shorter programs.

Sarcopenia and Tendon Health

Sarcopenia, defined by the European Working Group on Sarcopenia in Older People (EWGSOP2) as low muscle mass plus low muscle strength, compounds tendinopathy in older adults. Reduced muscle force generation means less effective mechanical loading of the tendon during rehabilitation. Protein supplementation at 1.6 g/kg/day alongside resistance exercise may improve both muscle and tendon outcomes; a 2021 RCT by Holwerda et al. found that leucine-enriched whey protein taken immediately post-exercise increased myofibrillar protein synthesis rates by 24% compared to placebo in men aged 65-75.

Fall Risk and Exercise Selection

Bilateral exercises (leg press, bilateral calf raise) are preferred over unilateral variations in older adults with balance deficits. Single-leg work is introduced only after the patient demonstrates stable single-leg stance for at least 30 seconds without upper-limb support.

Tendinopathy in Patients with Diabetes

Diabetes is one of the most clinically significant metabolic modifiers of tendon biology. Advanced glycation end-products (AGEs) accumulate in tendon collagen, increasing stiffness and reducing viscoelastic capacity. The result is a tendon that is paradoxically brittle: it resists deformation under low loads but fails catastrophically under sudden stress.

Epidemiology

A 2016 population-based study by Ranger et al. (N=23,400) found that individuals with type 2 diabetes had a 1.95-fold increased risk of Achilles tendon rupture compared to matched controls, independent of fluoroquinolone use and BMI. Rotator cuff tears were 60% more common in diabetic patients in the same dataset.

Glycemic Control and Tendon Healing

Hemoglobin A1c above 8% is associated with significantly slower tendon healing post-injury. The American Diabetes Association (ADA) 2024 Standards of Care state that glycemic targets should be individualized but note that HbA1c below 7% is appropriate for most non-pregnant adults without significant hypoglycemia risk. Optimizing glycemic control before elective tendon procedures is a reasonable clinical target.

Exercise Programming in Diabetic Patients

Peripheral neuropathy alters proprioception and pain perception, meaning diabetic patients may not experience the normal pain signal that guides load titration during rehabilitation. Clinicians should use objective load-monitoring tools (force plates, pressure-sensitive insoles) rather than relying solely on patient-reported pain. Foot inspections before and after each exercise session are mandatory in patients with established peripheral neuropathy.

Tendinopathy in Pregnant and Postpartum Women

Pregnancy produces a hormonal environment that directly affects connective tissue. Relaxin, secreted by the corpus luteum and placenta from the first trimester, increases collagen remodeling and ligament laxity. The effect extends to tendons. Combined with the mechanical demands of increasing body weight and altered gait biomechanics, this creates a window of heightened tendon vulnerability.

Safe Treatment Options During Pregnancy

Eccentric loading programs are generally safe throughout pregnancy, with exercise intensity adjusted to perceived exertion rather than specific load targets as pregnancy progresses. Corticosteroid injections are not absolutely contraindicated in the first trimester but are generally avoided thereafter given concerns about fetal adrenal suppression with repeated exposures. Ultrasound-guided injections that minimize systemic absorption are preferred when injection is unavoidable.

PRP carries no known teratogenic risk based on its autologous nature, but no RCT has evaluated PRP specifically in pregnant patients with tendinopathy. Off-label peptide therapies including BPC-157 are contraindicated during pregnancy given the absence of human safety data.

Postpartum Considerations

Relaxin levels normalize by approximately 3 months postpartum in non-breastfeeding women, and somewhat later in those who breastfeed. This extended laxity period means that postpartum athletes returning to high-impact sport before 3-4 months postpartum carry elevated tendon and ligament re-injury risk. A 2020 return-to-running guideline (Groom et al., published in the British Journal of Sports Medicine) recommends waiting at least 12 weeks postpartum before resuming running, with tendon loading progression starting no earlier than 6 weeks.

Tendinopathy Secondary to Fluoroquinolone Use

Fluoroquinolone antibiotics (ciprofloxacin, levofloxacin, moxifloxacin) carry an FDA black-box warning for tendon rupture, updated in 2016 to also include peripheral neuropathy. The mechanism involves inhibition of tenocyte matrix metalloproteinase activity, mitochondrial toxicity in tenocytes, and chelation of magnesium ions required for collagen cross-linking.

Who Is at Highest Risk

Risk factors that amplify fluoroquinolone-associated tendinopathy include:

• Age above 60
• Concurrent corticosteroid use (increases relative risk approximately 6-fold according to a 2002 case-control study by van der Linden et al., N=704)
• Renal impairment (reduces drug clearance)
• Prior tendon pathology

The Achilles tendon accounts for roughly 90% of fluoroquinolone-associated ruptures. Symptoms can begin within 48 hours of starting the antibiotic or appear up to 6 months after the course ends.

Management After Fluoroquinolone Exposure

The antibiotic should be discontinued as soon as tendon pain is identified and an alternative antibiotic substituted where possible. Weight-bearing should be restricted until rupture is excluded by ultrasound or MRI. Rehabilitation follows a modified slow-loading protocol with even more gradual progression than the standard program, given persistent tenocyte mitochondrial dysfunction that may last weeks after drug discontinuation.

Corticosteroid injections are absolutely contraindicated in fluoroquinolone-associated tendinopathy given the synergistic rupture risk documented by van der Linden et al.

Refractory Tendinopathy: PRP, BPC-157, and Sclerosing Injections

When 3-6 months of structured loading fails to produce adequate improvement (defined as VISA score improvement <15 points or persistent pain above 5/10 with sport-specific loads), adjunctive biological therapies are considered.

Platelet-Rich Plasma (PRP)

PRP delivers concentrated growth factors including PDGF, TGF-beta, and VEGF to the degenerated tendon. Evidence quality varies by tendon location.

For patellar tendinopathy, a 2021 RCT by Scott et al. (N=76) found no significant difference between leukocyte-rich PRP and dry needling at 12 weeks on VISA-P scores. For lateral epicondylalgia, a 2019 meta-analysis (N=18 RCTs, 1,066 patients) found PRP superior to corticosteroid at 12 months (weighted mean difference in pain scores: 1.4 points on a 10-point scale, P<0.05) but not at 4-8 weeks.

PRP is generally best positioned as a 12-month-plus adjunct for patients who have failed structured loading, not as a first-line treatment.

BPC-157

BPC-157 (body protection compound 157) is a synthetic 15-amino-acid peptide derived from a gastric protein. Animal studies show acceleration of tendon-to-bone healing and upregulation of growth hormone receptor expression in tenocytes. A 2017 study by Gwyer et al. reviewed preclinical data and concluded that BPC-157 promotes angiogenesis and collagen organization in injured tendons in rodent models.

No published RCT in humans exists for BPC-157 in tendinopathy as of this article's review date. It is used off-label by some sports medicine physicians at doses of 200-500 mcg subcutaneously or intramuscularly once daily for 4-8 weeks. Patients must be counseled that human safety and efficacy data are absent and that BPC-157 is not FDA-approved for any indication.

Sclerosing Injections

Polidocanol sclerotherapy targets the neovessels seen on Doppler ultrasound in chronic tendinopathy. A 2006 RCT by Hoksrud et al. (N=33) showed significant pain reduction in patellar tendinopathy at 12 weeks compared to saline. The effect is thought to result from destruction of nerve fibers accompanying the neovessels rather than from collagen repair.

Putting It Together: A Population-Specific Decision Framework

The table below summarizes how standard tendinopathy management adjusts across the five populations discussed. This framework is designed for clinical teams, not for patient self-management.

| Population | Load Progression Rate | Injection Options | Key Contraindication | Minimum Program Length | |---|---|---|---|---| | Elite Athlete | Standard (20%/week) | Corticosteroid max 1x/year, PRP after 3 months | Return to sport before LSI >90% | 12 weeks | | Older Adult (>60) | Slow (10%/week) | PRP preferred; corticosteroid with caution | Unilateral loading without balance screen | 20 weeks | | Type 2 Diabetes | Standard; objective monitoring required | PRP preferred; corticosteroid only if HbA1c <8% | Unmonitored load progression with neuropathy | 16 weeks | | Pregnancy/Postpartum | Perceived-exertion guided | Avoid corticosteroid after T1; no BPC-157 | Any off-label peptide | Until relaxin normalized (~3 months postpartum) | | Fluoroquinolone-exposed | Very slow (<5%/week) | None during acute phase; no corticosteroid | Corticosteroid (absolute contraindication) | 24 weeks |

Monitoring and When to Escalate

All patients should have VISA scores recorded at baseline, 6 weeks, 12 weeks, and every 12 weeks thereafter. An improvement of fewer than 15 points at 12 weeks in a patient fully adherent to the loading program warrants imaging review to exclude partial rupture, and referral to a sports medicine physician or orthopedic surgeon for discussion of injectable or surgical options.

Surgical intervention (tendon debridement, tenotomy) is reserved for patients who have failed at least 6 months of conservative management including structured loading plus at least one biological adjunct. Post-surgical rehabilitation follows the same population-specific loading principles described above, with timelines extended by approximately 50%.

The British Journal of Sports Medicine 2019 consensus statement on tendinopathy management states: "Load management is the cornerstone of all tendinopathy rehabilitation, and the specific program must be individualized to the patient's capacity, not to a generic protocol." That principle applies regardless of which special population a patient belongs to.

Start with a structured, monitored loading program. Add biologics only after 3-6 months of documented failure. In fluoroquinolone-exposed patients, exclude rupture with imaging before applying any load.