Achilles Tendinopathy: What Are The Best Treatment Options?

     When you perform a literature review on Achilles tendinopathy, be prepared to be inundated with a litany of citations. Literally hundreds of articles annually are dedicated to the investigation of this relatively enigmatic tendon. Some will focus on histological findings and others will feature anecdotal clinical investigations. A multitude of studies featuring newer, so-called “alternative” therapies are introduced and all the while, review-type articles of variable depth will litter your search.      Suffice it to say, filtering through this amount of information can be overwhelming to the practicing foot and ankle specialist. In spite of this, the diagnosis and treatment of various Achilles tendon disorders can and should be relatively straightforward. That is not to say that Achilles tendinopathy is a simple discussion. However, with a discriminating understanding of the current literature and a healthy dose of clinical experience, one can be quite adept at dealing with these pathologies.      Any discussion on the Achilles tendon should begin with an understanding of the currently accepted terminology. I prefer to separate proximal (“zone 1”) and distal (“zone 2”) pathologies. In the interest of clarity, “zone 2” or insertional disorders as well as ruptures (from zone 1) will be excluded from this discussion. However, the second case study below will discuss a complex surgical dilemma involving all aspects of Achilles tendinopathy.      Puddu is generally credited with the earliest, most appropriate classification of “zone 1” Achilles tendinopathy.1 The specific categories are peritendinitis, tendinosis, peritendinitis with tendinosis, and rupture. One should avoid the outdated terms “tendonitis” and “tenosynovitis” in any scientific discussion pertaining to this tendon. These terms are inappropriate given the lack of a true synovial sheath and the lack of evidence that the tendon manifests chemical inflammation.

A Guide To Key Anatomic Considerations

     In terms of general anatomic considerations, it is important to recall that the Achilles tendon is surrounded by a clear areolar tissue that allows movement between the tendon and the surrounding tissue. This paratenon is capable of manifesting an inflammatory response and can become adherent in conditions such as peritendinitis and/or tendinosis.      Another significant consideration is that of the rotation of fibers as the tendon courses distally. The fibers externally rotate beginning approximately 12 to 15 cm from the insertion and reaching a maximum of 2 to 5 cm proximal to it.2 This rotation may give insight as to why this area of the tendon is notoriously afflicted with pathology. It may also give credence to the use of orthoses in the context of an everted heel. Anecdotally speaking, I have had success with the use of orthoses in treating Achilles tendinopathy but only in cases involving a hyperpronated foot.      One final but significant anatomic consideration is the popular contention of a hypovascular or so-called “watershed” region of the Achilles tendon. The oft-cited Lagergren and Lindholm study from the 1950s is the primary basis of this notion.3 However, more recent studies and technological advances have questioned this decades-old scientific dogma.4 To this day, the debate about the vascular integrity of the Achilles tendon continues to evolve.

Pertinent Diagnostic Pearls

     Turning our attention to the clinical entity of Achilles tendinosis, we must be cognizant that the condition can have numerous comorbidities. In other words, the clinician should be able to identify and treat entities such as equinus, peritendinitis, pes planus, painful os trigonum and all insertional diagnoses. Indeed, differentiating these pathologies is critical to achieving therapeutic success.      Tendinosis, by definition, is a degenerative process of the Achilles, which manifests with the clinical hallmark of fusiform swelling. The patient rarely recalls a traumatic injury or sentinel event to induce the symptoms. While post-static dyskinesia is prevalent, pain is often exacerbated with increased exercise. In my practice, I have found that running is the primary inciting activity. Clinical signs are often the aforementioned fusiform swelling and intratendinous nodularity. On occasion, peritendinous swelling (peritendinitis) is visible concomitantly.      Radiographs are indicated although the condition is most likely a soft tissue injury in nature. However, it is important to rule out insertional pathology (Haglund’s, spurs, os trigonum, etc.) as well as anterior ankle pathology (spurs), which may limit ankle joint dorsiflexion. Further workup with MRI is also an option to rule out other pathology or determine the severity of the tendinosis. However, it often does not impact the initial treatment. Accordingly, one should reserve MRI for recalcitrant cases.

Top Tips On Managing Achilles Tendinosis

     Treatment, of course, is customized for each patient. However, one can follow the same general protocol. Initially, relative rest is recommended. Depending on the intensity of the symptoms and/or their duration, relative rest may range from boot immobilization to simple activity modification. Most patients require a boot for two to three weeks. Additionally, clinicians should encourage ice massage and NSAIDs for associated peritendinitis. Keep in mind, however, that pure tendinosis often does not respond to antiinflammatory interventions.      Subsequently, the patient will begin an organized, methodic and specific 12-week physical rehabilitation program. Alfredson is credited with characterizing the heavy load eccentric calf muscle training regimen that has truly revolutionized the treatment of Achilles tendinosis.5 It would behoove the practicing physician to obtain and understand this technique as it truly is the cornerstone of the conservative treatment. Furthermore, it is important to have a close relationship with the physical therapist in order to perform the protocol correctly. The results in the literature as well as my practice have been very encouraging.5,6      It is important to warn patients that this is a “no pain, no gain” proposition. Initially, the pain will increase but should slowly resolve over time. It also warrants mentioning that the hallmark fusiform swelling may not completely resolve despite the possibility of subjective symptom resolution.      In our clinic, we distribute a home program protocol handout to the patient to share with the therapist. While eccentric rehabilitation is the cornerstone of the proactive conservative measures, adjunctive physical therapy measures such as ultrasound and deep tissue massage may complement the treatment. In the athletic and active population, it is important to encourage alternative physical activities (biking or swimming) while the patient slowly recovers with the conservative treatment.      While most will achieve adequate success without invasive treatment, recalcitrant cases will invariably present. Newer alternative therapies are continuously evolving with variable clinical success. A non-exhaustive list includes extracorporeal shockwave, pulsed electromagnetic field, low level laser and microtenotomy therapy.7-10 Currently, I use low-level shockwave therapy with variable success in this pathology. However, much of the research in this arena involves more of a subjective clinical pain response rather than pure scientific investigation.      If surgery is necessary, it is again imperative to rule out any other adjunctive pathology that may either coexist with tendinosis or may appear to be Achilles tendinopathy, and is clarified with further diagnostic investigation. I recall one patient who was referred to me for surgical consultation of a chronic case of “Achilles tendonitis.” As it turns out, the patient had profound pain with hyperplantarflexion of the ankle and we ultimately diagnosed the patient with a painful os trigonum. Excision of the accessory bone was curative.      At this point, or on occasion earlier in the workup, an MRI is indicated. This will serve to demonstrate the exact location of the degeneration. Obtaining a MRI also enables the surgeon to quantify the percentage of tendon diameter involved. While there is no scientific standard to apply, I will transfer the flexor hallucis longus (FHL) tendon if over 40 percent of the diameter is affected. The FHL tendon is the primary candidate for tendon transfer in cases of Achilles tendinopathy in so much that it is an “in-phase” transfer and is quite accessible anatomically.

When Should You Perform A Tendon Transfer?

     The threshold of when to perform a tendon transfer is definitely a question of surgeon preference. Some contend that a transfer is essential in cases of Achilles tendinopathy while others have found success with debridement alone.      However, there is little debate that salvage tendinosis surgery should include a tendon transfer. There are various depictions of tendon transfer techniques in the literature.11,12 The technique I implement depends on the nature of the pathology. One of the primary considerations is how much tendon length is needed in the transfer. If the pathology focuses on the watershed area (zone 1), one can harvest the FHL tendon at the posteromedial ankle.      The author prefers a longitudinal, one-incision approach that curves anteriorly (following the natural course of the FHL tendon) distally. The ankle and the hallux are maximally plantarflexed as the tendon is transected as far distally as possible. Take care during this step as the neurovascular bundle will be in close proximity. The surgeon would then suture the FHL to the Achilles tendon, which has been debrided to excise all degenerated tissue. Preferably, surgeons would suture the tendon to the deep (anterior) aspect of the Achilles in a furrow which one can fashion with the aforementioned debridement.      Cases involving profound tendinosis and/or zone 2 pathology may require increased length of the FHL tendon graft. One can facilitate this with an additional incision at the sustentaculum talus or the proximal-medial arch. In one severe case, I transected the FHL tendon distal to the MTPJ. I subsequently pulled the tendon through an incision in the proximal arch and then finally through the posterior incision deep to the Achilles. This was necessary due to the profound nature of degeneration evident on the preoperative MRI.      It is important to keep in mind that the anatomy in the arch can be quite challenging. Further, the neurovascular structures are precariously at risk in this area of dissection. Suffice it to say, some review of cross-sectional anatomy as well as some extra preparation in the cadaver lab would be prudent before taking on some of the more involved cases. One can appropriately achieve the majority of transfers with the more straightforward one incision approach. The second case presentation below depicts a very complex case involving, among other things, an FHL tendon transfer.

How To Reduce The Risk Of Complications

     As with any other surgical procedure, complications do occur. In the case of any Achilles surgery, wound complications are most notable. Wound dehiscence and infection are always of concern. Gentle tissue dissection and meticulous paratenon closure are critical to safeguard against this occurrence. Interestingly, I have seen few, if any, long-term complaints with respect to postoperative hallux function after the transfer. The flexor hallucis brevis remains intact and the variable communication between the FHL and FDL tendons in the porta pedis presumably allows at least some residual power to the distal tendon stump. Perhaps the patient is so pleased to have a functional Achilles tendon that he or she has little concern for any decreased hallux flexion.      That said, take care when preparing any athletic or active patient for a tendon debridement with FHL transfer. The majority of these types of cases involve patients who are functionally debilitated as opposed to high-caliber athletes. The exact morbidity of FHL transfer in an athlete has not yet been scrutinized.      The following case studies demonstrate profoundly different clinical presentations and treatments of Achilles tendinopathy. Hopefully, they give some insights as to treatment options when dealing with these pathologies.

Case Study: When Eccentric Rehabilitation Makes An Impact

     A 55-year-old male presents with a chief complaint of a painful, thickened Achilles tendon. The exam demonstrates classic fusiform swelling and pain with palpation of the tendon. After a three-week period of relative rest (walking boot), the patient began a 12-week eccentric rehabilitation program.      Photos of initial, six-week and 12-week presentations demonstrate a relative decrease in the tendon volume. The patient reports no pain despite some residual tendon thickening and returned to full activity (walking and running) 14 weeks after the initial presentation. The patient reports no pain at 17 weeks and has been asked to follow up on a prn basis.

Case Study: When Complex Achilles Tendinosis Requires Surgical Treatment

     A 50-year-old male presents after a hyper-dorsiflexion injury to his ankle. He relates a history of feeling a “pop” in the Achilles tendon/heel area. The exam reveals a positive Thompson test (indicating total rupture) and a palpable gap noted just superior to calcaneal insertion. Radiographs reveal significant insertional spurring as well as calcification superiorly. Magnetic resonance imaging reveals that the proximal calcification is actually an avulsed fragment from the posterior calcaneus.      The patient undewent proximal gastrocnemius lengthening. I debrided the intratendinous calcification and tendinosis. I also remodeled the posterior calcaneus and performed an FHL transfer to the Achilles. Finally, I advanced and reinserted the Achilles tendon insertion with suture anchors.      We emphasized six weeks of non-weightbearing for the patient postoperatively. He subsequently wore a walking boot with a heel lift for six weeks. The patient healed uneventfully with a complete return to work as a plumber and a return to physical activities (walking/golfing) at three months postoperatively. The patient last presented at 16 weeks post-op without pain or weakness. I asked him to return on a PRN basis.      This complex reconstructive case aptly demonstrates some of the intricacies of Achilles tendon surgery. The surgery outlined above involved not only zone 1 and zone 2 pathologies but also the use of a proximal lengthening of the musculotendinous junction. As such, the surgeon should be well versed and trained in all aspects of the pathology if one is to take on this type of case. Rarely will one need to do all these procedures in one setting. However, it is important to be able to perform all of these procedures either independently or in concert to achieve the best outcome.      In this specific case, I considered staging the reconstruction. Initially, I could have performed a proximal lengthening with reattachment of the avulsed fragment to the posterior heel. Subsequently, I would have performed a posterior heel remodeling with insertional reattachment at a later date. Fortunately for this patient, he had an excellent outcome without any complications. However, the long and somewhat risky incision in this case could easily be criticized as perhaps too aggressive. This type of case speaks to the difficult decision-making process with which we all must contend. Hopefully, with continued scientific research and surgical experience, we can continue to evolve our surgical technique.

In Conclusion

     While the treatment of Achilles tendinosis continues to expand and evolve, there are few scientifically proven methods. Conservative management, focusing most notably on the eccentric loading protocol, should be at the core of any regimen. Alternative therapies such as low-energy shockwave show promise but warrant closer investigation.      One should reserve surgery for only the most recalcitrant cases. Unfortunately, the criteria with which to base the decision of specific procedural technique is largely based on the surgeon’s personal experience and philosophy. Hopefully, continued research (both clinical and histological) will afford a more scientific approach in the future. However, tendon research has never been more intensive than it is now. New technologies and treatments will likely follow. Dr. Blahous is a Fellow of the American College of Foot and Ankle Surgeons. He is in private practice at the Sports Medicine Clinic in Seattle.
 

References:

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