Achilles Tendonitis/Tendinopathy

WHAT IS ACHILLES TENDONITIS/TENDINOPATHY?

• The Achilles tendon connects the calf muscle to the heel bone and is the largest tendon in our body. This tendon controls lower leg movement when you walk, run, jump and stand up on your tiptoes.
  

• Achilles tendinopathy is a clinical syndrome characterized by pain, swelling, and impaired performance of the Achilles tendon.

• The condition can be classified into two main categories based on anatomical location:
  

  • insertional tendinopathy, which occurs at the insertion of the tendon into the calcaneus
    

  • noninsertional (midportion) tendinopathy, which affects the tendon 2-6 cm above the insertion.

WHAT CAUSES ACHILLES TENDINOPATHY?

• The pathophysiology of Achilles tendinopathy involves a failed healing response characterized by three stages: initially a reactive tendinopathy stage that can progress to tendon disrepair, and degenerative tendinopathy
  • Histologically, this process involves increased tenocyte proliferation, collagen
    disorganization, neovascularization, and increased glycosaminoglycans
    inthe tendon matrix [Li & Hua, 2016; Martin et al, 2018].
• While both insertional and midportion Achilles tendinopathy involve a failed healing response, insertional Achilles tendinopathy is characterized by compressive forces and calcification at the tendon-bone interface, whereas midportion Achilles tendinopathy is driven by tensile loading and shearing forces leading to collagen disorganization and neovascularization.

• Causes of insertional Achilles tendinopathy: Insertional Achilles tendinopathy is due to a complex pathophysiology characterized by degenerative changes at the tendon insertion into the calcaneus [Bullock et al, 2017; Thomas et al, 2010].
  • A key factor in insertional Achilles tendinopathy is the role of Haglund's syndrome, which is characterized by a bony prominence of the calcaneus. This bony prominence at the posterosuperior aspect of the calcaneus can impingement the retrocalcaneal bursa and compress the Achilles tendon.
    
  • This mechanical compression leads to chronic inflammation and mechanical irritation, contributing to the degenerative of the Achilles tendon and calcification.
  • Chronic impingement causes a retrocalcaneal bursitis, which can contribute to the pain and swelling observed in insertional Achilles tendinopathy
• Causes of midportion Achilles tendinopathy: Midportion Achilles tendinopathy is primarily driven by excessive mechanical stress, particularly tensile loading and shearing forces. These forces initiate a cascade of pathological changes within the tendon.
  • The etiology of midportion Achilles tendinopathy is multifactorial, involving both intrinsic factors (e.g., age, body weight, and biomechanical abnormalities) and extrinsic factors (e.g., training errors and poor footwear) [Li & Hua, 2016; Martin et al, 2018].
  • Most Achilles tendon injuries are a result of gradual wear and tear, and commonly
    occurs when due to overuse from high impact activities such as running and jumping cause tensile and shearing forces on the tendon.
    
    • Tensile loading refers to the stretching forces that occur during activities such as running and jumping. These forces can result in microtrauma within the tendon, resulting in collagen fibril disorganization, tenocyte proliferation, and increased production of non-collagenous matrix components. This disorganization weakens the tendon, alters fluid dynamics within the tendon matrix that results in stiffness, decreased strength, and impaired ability of the tendon fibers to effectively transfer forces [Martin et al, 20118; Nuri et al, 2018].
    • Shearing forces occur due to differential motion between tendon fascicles during activities that involve rapid changes in direction or high-impact landings. These forces contribute to the increased intratendinous pressure, further promoting tendon degeneration [Sun et al, 2015].
    • Neovascularization occurs as a response to mechanical stress and microtrauma, and involves the formation of new blood vessels within the tendon. These new blood vessels are not typically present in healthy tendons, and are driven by factors such as hypoxia, inflammatory cytokines, and mechanical loading. The ingrowth of new blood vessels is often accompanied by nerve fibers, which can lead to increased pain sensitivity. The neovessels also disrupt the normal tendon structure and function, leading to ineffective force transfer, altered tendon mechanics and increased intratendinous pressure that can contribute to the pain experienced by patients with midportion Achilles tendinopathy [Martin et al, 20118; Pringels et al, 2023; Pufe et al, 2005; Alfredson et al, 2003; Alfredson, 2004].

WHAT ARE THE SYMPTOMS OF ACHILLES TENDINOPATHY?

• Insertional Achilles tendinopathy and midportion Achilles tendinopathy present with distinct symptom profiles due to their different anatomical locations.

• Symptoms of Insertional Achilles tendinopathy include [Schroeder, 2002]:

  • Pain: Typically pain localizes to the posterior heel pain at the insertion of the Achilles tendon on the calcaneus. Patients often report that the pain is aggravated by increased activity and/or pressure from shoes.

  • Swelling: Swelling may be present at the tendon insertion site. Sometimes swelling or a prominence can be appreciated medially and laterally to the Achilles tendon insertion.

  • Radiographic findings: Bone spurs and calcifications can be seen at the insertion site for the Achilles tendon on radiographs.

  • Aggravating factors: Pain is often exacerbated by activities that involve lifting (dorsiflexing) the ankle, such as walking uphill. Wearing rigid backed shoes can also aggravate symptoms.

• Symptoms of midportion Achilles tendinopathy includeC:

  • Pain: Midsubstance Achilles tendinopathy typically presents with pain located 2-6 cm above the Achilles tendon insertion. This pain is often described as a combination of aching and tenderness [Martin et al, 2018].

  • Swelling: Swelling and thickening of the midportion of the Achilles tendon is common [Martin et al, 2018; Zwiers et al, 2016].

  • Functional impairment: Patients often experience impaired performance and pain during activities that load the tendon, such as running or jumping [Martin et al, 2018].

  • Morning stiffness: Midportion Achilles tendinopathy often causes stiffness that is worse in the morning or after inactivity and improves with activity [Janowski et al, 2023].
    

• In general insertional Achilles tendinopathy is characterized by pain and swelling at the tendon insertion, and is often aggravated by shoe pressure and dorsiflexion activities. Midportion Achilles tendinopathy presents with pain and swelling 2-6 cm proximal to the insertion, along with morning stiffness and impaired performance during tendon-loading activities.

HOW IS ACHILLES TENDONITIS/TENDINOPATHY DIAGNOSED?

• The diagnosis of Achilles tendinitis is based on detailed history, physical examination, and imaging. The location of pain while palpating the area is useful for distinguishing between an insertional or midsubstance Achilles injury.
• Imaging Techniques:
  • Radiographs (x-rays): Radiographs can be helpful in diagnosing insertional Achilles tendinopathy and in ruling out associated pathology. Radiographs can provide critical information about the bony structures at the tendon insertion site.
    • Radiographic findings commonly associated with insertional Achilles tendinopathy include: bone spurs at the insertion of the Achilles tendon onto the calcaneus; calcifications within the tendon from chronic inflammation and failed healing responses; bony prominence at the posterosuperior aspect of the calcaneus, known as Haglund's deformity, which contributes to mechanical impingement and inflammation of the insertional Achilles tendon [Schroeder, 2002; Thomas et al, 2010; Kang et al, 2012].
      
  • Ultrasound (US): Ultrasound can assess tendon structure, including tendon thickness, and the presence of neovascularization. Increased tendon thickness and hypoechoic areas correlate with pain and functional impairment, and neovascularization is associated with pain due tothe ingrowth of new blood vessels and nerve fibers [Sengkerij et al, 2009; van der Vlist et al, 2020; Martin et al, 2018; Sunding et al, 2016].
    
  • Magnetic Resonance Imaging (MRI): MRI can be used to assess both midportion and insertional Achilles tendinopathy. For midportion Achilles tendinopathy MRI is highly effective in identifying intratendinous changes, which indicate tendon degeneration and disorganization of collagen fibers. For insertional Achilles tendinopathy MRI is valuable in assessing the tendon insertion site, retrocalcaneal bursa, adjacent bone marrow, bone spurs,
    calcifications, and increased signal intensity at the tendon insertion,
    which are indicative of chronic inflammation and degeneration [Karjalainen et al, 2000; Grosse et al, 2015; Haims et al, 2000].
    

HOW IS ACHILLES TENDINOPATHY TREATED?

Conservative Management

• Initial treatment of Achilles tendonitis includes rest and activity modification, ice, NSAIDs, and physical therapy.
  

  • Eccentric strengthening exercises/physical therapy are the primary conservative treatment for both midportion and insertional Achilles tendinopathy.

    • For midportion Achilles tendinopathy, studies have consistently shown significant improvements in pain and function with eccentric strengthening.
      In a study by Fahlström et al., 89% of patients with midportion Achilles tendinopathy reported satisfactory outcomes and a significant reduction in pain after a 12-week eccentric training regimen [Fahlstrom et al, 2003].
      
    • A randomized controlled trial by Roos et al. reported significant pain
      reduction and functional improvement sustained over a year [Roos et al, 2004]. Similarly, a systematic review and meta-analysis by Wilson et al. found moderate evidence favoring eccentric exercises over control for improving pain and function in midportion tendinopathy [Wilson et al, 2018]. Heavy slow resistance (HSR) training has shown similar efficacy to eccentric exercises for midportion Achilles tendinopathy. Beyer et al. found no significant differences in clinical outcomes between HSR and eccentric training, although patient satisfaction tended to be higher with HSR at 12 weeks [Beyer et al, 2015].
      
    • For insertional Achilles tendinopathy, the outcomes of an eccentric strengthening program are less favorable. Fahlström et al. reported that only 32% of patients with insertional Achilles tendinopathy experienced satisfactory results with the same eccentric training regimen as for midportion Achilles tendinopathy [Fahlstrom et al, 2003]. However, a modified eccentric training protocol that avoids loading the ankle into dorsiflexion has shown promising results, with 67% of patients reporting satisfaction and significant pain reduction [Jonsson et al, 2008].

Shockwave Therapy

• Extracorporeal shockwave therapy (ESWT), initiates the body’s natural healing process with the aim of reduction in pain and increase in function, and has been studied for both insertional and midportion Achilles tendinopathy, with varying outcomes.

  • For midportion Achilles tendinopathy, the outcomes of ESWT are also favorable but somewhat less pronounced compared to insertional tendinopathy. Mani-Babu et al. reported that ESWT is comparable to eccentric loading exercises for midportion Achilles tendinopathy in the short term, and combining ESWT with eccentric loading may produce superior outcomes. The American Physical Therapy Association guidelines also support the use of ESWT in combination with eccentric exercises for chronic midportion Achilles tendinopathy, noting improvements in VISA-A scores, pain, and function [Mani-Babu et al, 2015; Martin et al, 2018].
    
  • For insertional Achilles tendinopathy, ESWT has shown promising results. A systematic review by Mani-Babu et al. found moderate evidence indicating that ESWT is more effective than eccentric loading exercises in the short term for insertional Achilles tendinopathy [Mani-Babu et al, 2015]. Additionally, a study by Rompe et al. demonstrated that ESWT provided significantly better outcomes in terms of pain reduction and functional improvement compared to eccentric loading at four months follow-up [Rompe et al, 2008]. Another study by Furia reported that high-energy ESWT resulted in significant pain reduction and functional improvement, with 83% of patients achieving successful outcomes at 12 months [Furia, 2006].
    

Platelet Rich Plasma (PRP) Injections

• PRP therapy concentrates the growth factors in your own blood, which can decrease inflammation, improve function and control joint pain. The evidence for the use of platelet-rich plasma (PRP) in the treatment of midportion and insertional Achilles tendinopathy is mixed and somewhat controversial. PRP injections has shown promise for soft tissue injuries, but has not consistently demonstrated superior outcomes compared to placebo or sham treatments for midportion Achilles tendinopathy.

  • For midportion Achilles tendinopathy,several studies have evaluated the efficacy of PRP. A randomized controlled trial by de Vos et al. found no significant difference in improvement in Victorian Institute of Sports Assessment-Achilles (VISA-A) scores between PRP and saline injections at 24 weeks [de Vos et al, 2010]. Similarly, a study by Kearney et al. reported no significant improvement in VISA-A scores at 6 months when comparing PRP to sham injections [Kearney et al, 2021]. A meta-analysis by Liu et al. also concluded that PRP did not show superior efficacy over placebo in improving pain and function at 12 and 24 weeks [Liu et al, 2019]. In contrast, Monto's study demonstrated significant improvements in American Orthopaedic Foot & Ankle Society (AOFAS) scores and imaging abnormalities in patients treated with PRP at 3 months post-treatment and sustained improvement at 24 months, suggesting potential benefits in chronic cases resistant to traditional nonoperative treatments [Monto, 2012]. Boesen
    et al. found that PRP combined with eccentric training significantly
    improved VISA-A scores and reduced pain compared to placebo, with
    notable improvements at 24 weeks [Boesen et al, 2017].
    
  • For insertional Achilles tendinopathy, the evidence is less robust.

"Stem Cell" Procedures

• Stem cell injections use your own cells to stimulate the growth of healthy tissue within the Achilles tendon to improve pain and function.The outcomes of mesenchymal stem cell (MSC) therapy, micro-fragmented adipose tissue (MFAT) therapy, and bone marrow aspirate concentrate (BMAC) therapy for treating insertional and midportion Achilles tendinopathy are as follows:

  • Mesenchymal Stem Cell (MSC) Therapy: MSC therapy has shown promising results in treating Achilles tendinopathy. A study by Goldberg et al. demonstrated that autologous bone marrow-derived MSC injections for midportion Achilles tendinopathy resulted in significant improvements in pain and function, with no serious adverse events reported at 24 weeks [Goldberg et al, 2024]. Another study by Smith et al. in a large animal model showed that MSC therapy improved tendon structure and function, suggesting potential benefits for human tendinopathy [Smith et al, 2013].
    
  • Micro-Fragmented Adipose Tissue (MFAT) Therapy: There is limited direct evidence on the use of MFAT specifically for Achilles tendinopathy. However, adipose-derived stem cells (ASCs), which are a component of MFAT, have shown beneficial effects in preclinical models. Oshita et al. demonstrated that ASCs improved collagenase-induced tendinopathy in a rat model, with significant improvements in tendon histology and collagen composition [Oshita et al, 2016].
    
  • Bone Marrow Aspirate Concentrate (BMAC) Therapy: BMAC therapy has shown positive outcomes for both insertional and midportion Achilles tendinopathy. Thueakthong et al. reported significant pain reduction and functional improvement in patients with recalcitrant Achilles tendinopathy treated with iliac crest BMAC injections, with sustained benefits observed up to 48 weeks post-treatment and no complications [Thueakthong et al, 2021].
    

Scrapping Procedures/Plantaris tendon excision

• The evidence supporting Achilles tendon scraping procedures for treating midportion and insertional Achilles tendinopathy is as follows:
  • For midportion Achilles tendinopathy, several studies have demonstrated positive outcomes with Achilles tendon scraping. Alfredson et al. reported significant improvements in pain and function using ultrasound guided mini-surgery (scraping) outside the ventral tendon. In their study, 89% of patients were satisfied and returned to full activity, with an average follow-up of 18 months [Alfredson, 2011]. Another study by Masci et al. showed that Achilles scraping combined with plantaris tendon removal resulted in significant improvements in function and tendon structure at 24 months follow-up [Masci et al, 2021]. Calder et al. also reported that plantaris tendon excision using a mini-incision technique significantly improved symptoms in elite athletes with non-insertional Achilles tendinopathy, with a high rate of return to sport and patient satisfaction [Calder et al, 2015].
    
  • For insertional Achilles tendinopathy, the evidence is less extensive but still promising. Bedi et al. reported positive outcomes in high-level athletes treated with plantaris excision and ventral paratendinous scraping, and there was a significant improvement in the aligned fibrillar structure of the tendon as confirmed by ultrasound tissue characterization [Bedi et al, 2016].

Minimially Invasive Tenotomy

• The evidence for the effectiveness of percutaneous tenotomy in treating Achilles tendon pathology is supported by several studies demonstrating significant improvements in pain and functionality. Minimally invasive tenotomy procedures typically invovle neither general anesthesia nor larger incisions seen with traditional open surgery, and can be an attractive alternative to traditional tenotomy and has demonstrated a low recovery time and few complications [Dunkow et al, 2004]. Initially performed unguided and with a surgical scalpel blade with long term efficacy [Maffulli et al, 1997; Maffulli et al, 2013]. Recent studies have used ultrasound guidance and less invasive devices, with the following outcomes:

  • For midportion Achilles tendinopathy, a prospective cohort study by Lavalleeand Bush evaluated a minimally invasive tenotomy with ultrasoundguidance in nonelite active adults with various tendinopathies using the Tenex device, including the Achilles tendon (n=27). The study reported statistically significant decreases in pain scores at one week post-procedure and continued improvement with a significant decrease in pain and improved functionality scores at one year [Lavallee and Bush, 2021]. Testa et al. reported on the long-term outcomes of a longitudinal tenotomy with ultrasound-guided using a percutaneous approach in athletes with chronic Achilles tendinopathy. The study found that 47 out of 63 patients had excellentor good outcomes at a mean follow-up of 51 months. The procedure was performed with a number 11 surgical scalpel blade, and was noted to be simple, minimally invasive, and effective, with no significant complications [Testa et al, 2002]. A meta-analysis by Shomal Zadeh et al. assessed the efficacy of percutaneous ultrasound-guided needle tenotomy for chronic tendinopathy, including the Achilles tendon. The analysis showed significant pain reduction and functional improvement at short-term, intermediate-term, and long-term follow-ups, with a low complication rate [Shomal Zadeh et al, 2023].
  • For insertional Achilles tendinopathy, minimally invasive tenotomy typically involves addressing either the Haglund deformity (learn more here) or the calcaneal enthesiophyte.

Surgical Intervention

• In most cases, nonsurgical treatment options are effective, although it may take a few months for symptoms to completely subside. When these noninvasive treatment options fail, surgical options can be considered. The type of surgery that will be recommended will depend on the location and amount of damage to the tendon. Open surgery generally involves a longer recovery time and higher complication rates compared to minimally invasive techniques.

  • For midportion Achilles tendinopathy, surgical options include open or minimally invasive procedures such as debridement and longitudinal tenotomies. A systematic review by Lohrer et al. reported a mean success rate of 83.4% for surgical treatments, with a complication rate of 6.3% [Lohrer et al, 2016]. Another systematic review by Baltes et al. found that minimally invasive and endoscopic procedures yield lower complication rates with similar patient satisfaction compared to open procedures [Baltes et al, 2017].
    
  • For insertional Achilles tendinopathy, surgical interventions often involve debridement of the Achilles insertion, resection of the superior calcaneus, and re-attachment with suture anchors.
    

References

Alfredson H. Chronic tendon pain--implications for treatment: an update. Curr Drug Targets. 2004 Jul;5(5):407-10.

Alfredson H. Ultrasound and Doppler-guided mini-surgery to treat midportion Achilles tendinosis: results of a large material and a randomised study comparing two scraping techniques. Br J Sports Med. 2011 Apr;45(5):407-10.

Alfredson H, Ohberg L, Forsgren S. Is vasculo-neural ingrowth the cause of pain in chronic Achilles tendinosis? An investigation using ultrasonography and colour Doppler, immunohistochemistry, and diagnostic injections. Knee Surg Sports Traumatol Arthrosc. 2003 Sep;11(5):334-8.

Baltes TPA, Zwiers R, Wiegerinck JI, van DijkCN. Surgical treatment for midportion Achilles tendinopathy: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2017 Jun;25(6):1817-1838.

Bedi HS, Jowett C, Ristanis S, Docking S, Cook J. Plantaris Excision and Ventral Paratendinous Scraping for Achilles Tendinopathy in an Athletic Population. Foot Ankle Int. 2016 Apr;37(4):386-93.

Beyer R, Kongsgaard M, Hougs Kjær B, Øhlenschlæger T, Kjær M, Magnusson SP. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy: A Randomized Controlled Trial. Am J Sports Med. 2015 Jul;43(7):1704-11.

Boesen AP, Hansen R, Boesen MI, Malliaras P, Langberg H. Effect of High-Volume Injection, Platelet-Rich Plasma, and Sham Treatment in Chronic Midportion Achilles Tendinopathy: A Randomized Double-Blinded Prospective Study. Am J Sports Med. 2017 Jul;45(9):2034-2043.

Bullock MJ, Mourelatos J, Mar A. Achilles Impingement Tendinopathy on Magnetic Resonance Imaging. J Foot Ankle Surg. 2017 May-Jun;56(3):555-563.

Calder JD, Freeman R, Pollock N. Plantaris excision in the treatment of non-insertional Achilles tendinopathy in elite athletes. Br J Sports Med. 2015 Dec;49(23):1532-4.

Chraim M, Alrabai HM, Krenn S, Bock P, Trnka HJ. Short-Term Results of Endoscopic Percutaneous Longitudinal Tenotomy for Noninsertional Achilles Tendinopathy and the Presentation of a Simplified Operative Method. Foot Ankle Spec. 2019 Feb;12(1):73-78.

de Vos RJ, Weir A, van Schie HT, Bierma-Zeinstra SM, Verhaar JA, Weinans H, Tol JL. Platelet-rich plasma injection for chronic Achilles tendinopathy: a randomized controlled trial. JAMA. 2010 Jan 13;303(2):144-9.

Dunkow PD, Jatti M, Muddu BN. A comparison of open and percutaneous techniques in the surgical treatment of tennis elbow. J Bone Joint Surg Br. 2004 Jul;86(5):701-4.

Fahlström M, Jonsson P, Lorentzon R, Alfredson H. Chronic Achilles tendon pain treated with eccentric calf-muscle training. Knee Surg Sports Traumatol Arthrosc. 2003 Sep;11(5):327-33.

Furia JP. High-energy extracorporeal shock wave therapy as a treatment for insertional Achilles tendinopathy. Am J Sports Med. 2006 May;34(5):733-40.

Goldberg AJ, Masci L, O'Donnell P, Green R, Brooking D, Bassett P, Lowdell MW, Smith RKW. Autologous bone marrow derived mesenchymal stem cells are safe for the treatment of Achilles tendinopathy. Sci Rep. 2024 May 19;14(1):11421.

Grosse U, Syha R, Hein T, Gatidis S, Grözinger G, Schabel C, Martirosian P, Schick F, Springer F. Diagnostic value of T1 and T2 * relaxation times and off-resonance saturation effects in the evaluation of Achilles tendinopathy by MRI at 3T. J Magn Reson Imaging. 2015 Apr;41(4):964-73.

Haims AH, Schweitzer ME, Patel RS, Hecht P, Wapner KL. MR imaging of the Achilles tendon: overlap of findings in symptomatic and asymptomatic individuals. Skeletal Radiol. 2000 Nov;29(11):640-5.

Janowski AJ, Post AA, Heredia-Rizo AM, Mosby H, Dao M, Law LF, Bayman EO, Wilken JM, Sluka KA, Chimenti RL. Patterns of movement-evoked pain during tendon loading and stretching tasks in Achilles tendinopathy: A secondary analysis of a randomized controlled trial. Clin Biomech (Bristol). 2023 Oct;109:106073.

Jonsson P, Alfredson H, Sunding K, Fahlström M, Cook J. New regimen for eccentric calf-muscle training in patients with chronic insertional Achilles tendinopathy: results of a pilot study. Br J Sports Med. 2008 Sep;42(9):746-9.

Kang S, Thordarson DB, Charlton TP. Insertional Achilles tendinitis and Haglund's deformity. Foot Ankle Int. 2012 Jun;33(6):487-91.

Karjalainen PT, Soila K, Aronen HJ, Pihlajamäki HK, Tynninen O, Paavonen T, Tirman PF. MR imaging of overuse injuries of the Achilles tendon. AJR Am J Roentgenol. 2000 Jul;175(1):251-60.

Kearney RS, Ji C, Warwick J, Parsons N, Brown J, Harrison P, Young J, Costa ML; ATM Trial Collaborators. Effect of Platelet-Rich Plasma Injection vs Sham Injection on Tendon Dysfunction in Patients With Chronic Midportion Achilles Tendinopathy: A Randomized Clinical Trial. JAMA. 2021 Jul 13;326(2):137-144.

Lavallee M, Bush C. Ultrasound-Guided Percutaneous Tenotomy and Its Associated Pain Reduction and Functionality Outcomes in Nonelite Active Adults. Am J Phys Med Rehabil. 2021 Apr 1;100(4):349-353.

Liu CJ, Yu KL, Bai JB, Tian DH, Liu GL. Platelet-rich plasma injection for the treatment of chronic Achilles tendinopathy: A meta-analysis. Medicine (Baltimore). 2019 Apr;98(16):e15278.

Lohrer H, David S, Nauck T. Surgical treatment for achilles tendinopathy - a systematic review. BMC Musculoskelet Disord. 2016 May 10;17:207.

Maffulli N, Oliva F, Testa V, Capasso G, Del Buono A. Multiple percutaneous longitudinal tenotomies for chronic Achilles tendinopathy in runners: a long-term study. Am J Sports Med. 2013 Sep;41(9):2151-7.

Maffulli N, Testa V, Capasso G, Bifulco G, Binfield PM. Results of percutaneous longitudinal tenotomy for Achilles tendinopathy in middle- and long-distance runners. Am J Sports Med. 1997 Nov-Dec;25(6):835-40.

Mani-Babu S, Morrissey D, Waugh C, Screen H, Barton C. The effectiveness of extracorporeal shock wave therapy in lower limb tendinopathy: a systematic review. Am J Sports Med. 2015 Mar;43(3):752-61.

Martin RL, Chimenti R, Cuddeford T, Houck J, Matheson JW, McDonough CM, Paulseth S, Wukich DK, Carcia CR. Achilles Pain, Stiffness, and Muscle Power Deficits: Midportion Achilles Tendinopathy Revision 2018. J Orthop Sports Phys Ther. 2018 May;48(5):A1-A38.

Masci L, Neal BS, Wynter Bee W, Spang C, Alfredson H. Achilles Scraping and Plantaris Tendon Removal Improves Pain and Tendon Structure in Patients with Mid-Portion Achilles Tendinopathy-A 24 Month Follow-Up Case Series. J Clin Med. 2021 Jun 18;10(12):2695.

Monto RR. Platelet rich plasma treatment for chronic Achilles tendinosis. Foot Ankle Int. 2012 May;33(5):379-85.

Nuri L, Obst SJ, Newsham-West R, Barrett RS. Three-dimensional morphology and volume of the free Achilles tendon at rest and under load in people with unilateral mid-portion Achilles tendinopathy. Exp Physiol. 2018 Mar 1;103(3):358-369.

Oshita T, Tobita M, Tajima S, Mizuno H. Adipose-Derived Stem Cells Improve Collagenase-Induced Tendinopathy in aRat Model. Am J Sports Med. 2016 Aug;44(8):1983-9.

Pringels L, Vanden Bossche L, Wezenbeek E, Burssens A, Vermue H, Victor J, Chevalier A. Intratendinous pressure changes in the Achilles tendon during stretching and eccentric loading: Implications for Achilles tendinopathy. Scand J Med Sci Sports. 2023 May;33(5):619-630.

Pufe T, Petersen WJ, Mentlein R, Tillmann BN. The role of vasculature and angiogenesis for the pathogenesis of degenerative tendons disease. Scand J Med Sci Sports. 2005 Aug;15(4):211-22.

Rompe JD, Furia J, Maffulli N. Eccentric loading compared with shock wave treatment for chronic insertional achilles tendinopathy. A randomized, controlled trial. J Bone Joint Surg Am. 2008 Jan;90(1):52-61.

Roos EM, Engström M, Lagerquist A, Söderberg B. Clinical improvement after 6 weeks of eccentric exercise in patients with mid-portion Achilles tendinopathy -- a randomized trial with 1-year follow-up. Scand J Med Sci Sports. 2004 Oct;14(5):286-95.

Schroeder BM; American College of Foot and Ankle Surgeons. American College of Foot and Ankle Surgeons: Diagnosis and treatment of heel pain. Am Fam Physician. 2002 Apr 15;65(8):1686, 1688.

Sengkerij PM, de Vos RJ, Weir A, van Weelde BJ, Tol JL. Interobserver reliability of neovascularization score using power Doppler ultrasonography in midportion achilles tendinopathy. Am J Sports Med. 2009 Aug;37(8):1627-31.

Shomal Zadeh F, Shafiei M, Shomalzadeh M, Pierce J, Thurlow PC, Chalian M. Percutaneous ultrasound-guided needle tenotomy for treatment of chronic tendinopathy and fasciopathy: a meta-analysis. Eur Radiol. 2023 Oct;33(10):7303-7320.

Silbernagel KG, Hanlon S, Sprague A. Current Clinical Concepts:
Conservative Management of Achilles Tendinopathy. J Athl Train. 2020
May;55(5):438-447.

Smith RK, Werling NJ, Dakin SG, Alam R, Goodship AE, Dudhia J. Beneficial effects of autologous bone marrow-derived mesenchymal stem cells in naturally occurring tendinopathy. PLoS One. 2013 Sep 25;8(9):e75697.

Sun YL, Wei Z, Zhao C, Jay GD, Schmid TM, Amadio PC, An KN. Lubricin in human achilles tendon: The evidence of intratendinous sliding motion and shear force in achilles tendon. J Orthop Res. 2015 Jun;33(6):932-7.

Sunding K, Fahlström M, Werner S, Forssblad M, Willberg L. Evaluation of Achilles and patellar tendinopathy with greyscale ultrasound and colour Doppler: using a four-grade scale. Knee Surg Sports Traumatol Arthrosc. 2016 Jun;24(6):1988-96.

Testa V, Capasso G, Benazzo F, Maffulli N. Management of Achilles tendinopathy by ultrasound-guided percutaneous tenotomy. Med Sci Sports Exerc. 2002 Apr;34(4):573-80.

Thomas JL, Christensen JC, Kravitz SR, Mendicino RW, Schuberth JM, Vanore JV, Weil LS Sr, Zlotoff HJ, Bouché R, Baker J; American College of Foot and Ankle Surgeons heel pain committee. The diagnosis and treatment of heel pain: a clinical practice guideline-revision 2010. J Foot Ankle Surg. 2010 May-Jun;49(3 Suppl):S1-19.

Thueakthong W, de Cesar Netto C, Garnjanagoonchorn A, Day J, Friedman G, Auster H, Tan E, Schon LC. Outcomes of iliac crest bone marrow aspirate injection for the treatmentof recalcitrant Achilles tendinopathy. Int Orthop. 2021 Sep;45(9):2423-2428.

van der Vlist AC, Veen JM, van Oosterom RF, van Veldhoven PLJ, Verhaar JAN, de Vos RJ. Ultrasound Doppler Flow in Patients With Chronic Midportion Achilles Tendinopathy: Is Surface Area Quantification a Reliable Method? J Ultrasound Med. 2020 Apr;39(4):731-739.

Wilson F, Walshe M, O'Dwyer T, Bennett K, Mockler D, Bleakley C. Exercise, orthoses and splinting for treating Achilles tendinopathy: a systematic review with meta-analysis. Br J Sports Med. 2018 Dec;52(24):1564-1574.

Zwiers R, Wiegerinck JI, van Dijk CN. Treatment of midportion Achilles tendinopathy: an evidence-based overview. Knee Surg Sports Traumatol Arthrosc. 2016 Jul;24(7):2103-11.

Other Foot/Ankle Conditions

• Ankle Sprain
• Calcaneal (Achilles) Spur
• Haglund deformity
• Peroneal Nerve Entrapment
• Plantar fasciitis
• Sever’s Disease
• Tendon pain (PTTD)