DEFINITION

Insertional and midsubstance Achilles tendinosis is a painful degenerative process that arises due to mechanical and vascular factors and affects the paratenon and collagen fibers.

It is most commonly seen in patients in their mid-40s and older.

 

 

ANATOMY

 

The Achilles tendon, the largest tendon in the body, connects the gastrocsoleus complex to the calcaneus (FIG 1).

 

It is covered by a paratenon without a definite tendon sheath.

 

The blood supply of the tendon arises distally from calcaneal arterioles and proximally from intramuscular branches. There is a relatively hypovascular, or watershed, area 2 to 4 cm proximal to the tendon insertion.

 

PATHOGENESIS

 

Mechanical and vascular factors contribute to the development of tendinosis. The process begins with mechanical pressure on the insertion of the Achilles tendon from internal factors, a Haglund deformity, or external factors, such as a firm heel counter. Retrocalcaneal bursitis develops initially without Achilles tendon involvement. Increasing prominence of the posterolateral calcaneal tuberosity or hindfoot malalignment (ie, varus heel) can cause tendon collagen fiber injury and further inflammation of the retrocalcaneal bursa.

 

Progressive thickening of the retrocalcaneal bursa and peritendinous tissue increases mechanical pressure on the tendon, impeding blood flow, and hampering the normal repair process, leading to a thickened, degenerative tendon.

 

 

 

FIG 1 • The Achilles tendon and its relationship to the FHL tendon.

 

 

With dysvascular changes associated with aging, the tendon becomes increasingly thick and painful. Radiographs at this point may show a spur or calcification at the Achilles insertion.

 

NATURAL HISTORY

 

The natural history of the pathologic process most likely is a continuum that begins with retrocalcaneal bursitis and ends in chronic Achilles tendinosis.

 

Patient activity becomes more restricted due to increased pain and weakness.

 

Age-dependent changes in collagen quality and decreased vascularity contribute to the development of tendinosis.

 

As the degenerative process becomes chronic, the tendon becomes mechanically deficient and more susceptible to rupture.

 

Symptoms become unremitting as the disease progresses.

PATIENT HISTORY AND PHYSICAL FINDINGS

 

 

Achilles tendinosis causes pain and swelling of the diseased segment of tendon. Pain increases with physical activity and with direct pressure on the affected tendon.

 

Patients with seronegative arthropathies, spondyloarthropathies, hypercholesterolemia, sarcoidosis, and renal transplant have an increased incidence of Achilles tendinopathy.

 

The patient should be assessed for hyperpronation or heel varus deformities, which can cause eccentric Achilles tendon loading. If either is present, an orthosis to keep the hindfoot in neutral may be necessary.

 

Ankle dorsiflexion is measured with the knee flexed and extended to assess for gastrocnemius or Achilles tendon tightness. If excessive tightness is present, a gastrocnemius recession should be considered along with the flexor hallucis longus (FHL) transfer.

 

With the patient prone on the examining table, the Achilles tendon is palpated to localize the area of thickening and tenderness (either insertional or noninsertional). Assess the size of the calcaneal tuberosity; if it is enlarged, excision of this prominence should be considered to reduce mechanical pressure on the diseased Achilles tendon.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Radiographs are useful in evaluating the extent of tendon calcification and presence of a Haglund deformity (FIG 2A).

 

Although magnetic resonance imaging (MRI) scanning is not essential for preoperative planning, it can be beneficial in estimating the amount of degenerative tendon to be excised (FIG 2B,C).

 

 

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FIG 2 • A. Lateral radiograph of the heel revealing a prominent calcaneal tuberosity and calcification of the Achilles insertion. B. This sagittal MRI scan demonstrates increased signal in the Achilles insertion. C. This axial MRI scan of the Achilles insertion reveals diseased fibers.

 

DIFFERENTIAL DIAGNOSIS

Haglund deformity Os trigonum

 

Retrocalcaneal bursitis Peritendinitis

Seronegative spondyloarthropathy Insertional tendinopathy

Achilles tendinosis

 

 

NONOPERATIVE MANAGEMENT

 

Nonsurgical treatment of insertional or noninsertional Achilles tendinosis includes rest, immobilization, and rehabilitation.

 

 

Immobilization can include casting, a cast brace, and a custom-molded ankle-foot orthosis (AFO). Structural abnormalities such as heel varus are addressed with wedges or orthotics, or both.

 

Training regimens are modified to reduce stress on the affected tendon.

 

Physical therapy for heavy load eccentric strengthening exercises has been found to be effective for Achilles tendinopathy and may be superior to conventional treatment regimens and comparable to open débridement of the tendon.

 

SURGICAL MANAGEMENT

 

Surgery is performed only on those patients who have intractable pain and impaired function or those who have failed previous tendon débridement or Haglund resection alone.

 

 

Most people in this patient group have a chronic Achilles tendon deficiency and are sedentary, overweight, and have radiographic or MRI evidence of a thickened, calcific Achilles insertion.

 

Most treatments that have been described focus on removing mechanical pressure from the diseased tendon (eg, excising the posterosuperior calcaneal tuberosity), débridement of the diseased tendon, or augmentation of the remaining, débrided tendon (ie, FHL, peroneus brevis, plantaris).

 

The bulk of surgical treatment is discussed in the following sections and in the Techniques section.

 

Preoperative Planning

 

The extent and location of diseased tendon must be identified. The area of tendon degeneration most often is the distal 2 to 4 cm. The degeneration also may be isolated at the midsubstance.

 

The patient must understand preoperatively that the time to maximum improvement could be prolonged (average 8.2 months).

 

If the surgeon wants to loop the transferred FHL through the calcaneus at the time of the transfer and more tendon length consequently will be needed, the FHL should be harvested from the midmost at Henry knot and pulled out the posterior incision.

 

Positioning

 

The patient is placed prone on the operating table with a soft bump anterior to the ankle (FIG 3).

 

Approach

 

Various incisions have been used to approach the diseased tendon.

 

 

Incisions that have been recommended include central splitting, medial and/or lateral longitudinal pretentious,

or medial with a transverse L-shaped extension distally.

 

All of these incisions can be used successfully to expose and débride diseased tissue, but if augmentation of the Achilles tendon is anticipated, a medial incision will give the best access to the FHL.

 

Whatever incision is selected, it should be done sharply through the subcutaneous tissue to the paratenon, taking care not to dissect horizontally, thus reducing the risk of vascular compromise of the soft tissues overlying the tendon.

 

 

 

FIG 3 • The patient is positioned prone on the operating table.

 

 

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TECHNIQUES

• Exposure and Tendon Preparation

  A 10-cm posteromedial incision is made starting near the junction of the proximal and middle thirds of the Achilles tendon and stopping distally at the tendinous insertion into the calcaneal tuberosity.

  The incision is made sharply through the subcutaneous tissue to the paratenon, taking care not to dissect horizontally, thereby reducing the risk of vascular compromise of the soft tissue overlying the Achilles tendon.

  An L-shaped extension of the incision distally is performed if extensive débridement of the Achilles tendon is anticipated and better exposure of the lateral tendon insertion is needed (TECH FIG 1A).

  The substance of the tendon is carefully inspected. Any amorphous (codfish-flesh appearing), calcified, or ossified tissue of the tendon is excised, leaving only relatively healthy, normally striated tissue. Usually, more than 50% of the cross-section is removed.

   

   

   

  TECH FIG 1 • A. Full-thickness, L-shaped incision to increase exposure of the diseased Achilles tendon. B. Typical location of diseased Achilles. C. Area of wedge resection of the Achilles insertion in preparation for repair. D. Area of bone resection. E. Partial ostectomy performed through the resected tendon. (continued)

   

   

  The degenerative, calcified area of tendon is best excised by removing a wedge-shaped piece of tissue from the insertion of the Achilles tendon (TECH FIG 1B,C).

   

  In all cases, a partial calcaneal ostectomy is performed at the superoposterior aspect to decompress the Achilles tendon insertion (TECH FIG 1D-F). This also improves exposure to the anterior aspect of the tendon, aiding in tendon inspection and débridement.

   

  With the degenerative tissue removed, the triangular fat pad anterior to the Achilles tendon is excised, exposing the deep posterior fascia (TECH FIG 1G).

   

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  TECH FIG 1 • (continued) F. Resected bone and decompressed tendon insertion. G. The triangular fat pad is excised, and the deep posterior fascia is exposed.

• Tendon Transfer

   

  The fascia overlying the posterior compartment of the leg is incised longitudinally to the proximal extent of the FHL muscle body. The FHL tendon is identified (TECH FIG 2A). The flexor retinaculum is released along the medial aspect of the hindfoot to further expose the FHL.

   

  Gentle retraction of the neurovascular bundle with a blunt retractor allows safe visualization of the tendon distally (TECH FIG 2B,C).

   

  The FHL is transected as far distal as possible with the ankle and hallux in maximum plantarflexion.

   

  Transection of the tendon is done medial to lateral to avoid accidental injury to the neurovascular structures.

   

   

   

  TECH FIG 2 • A. The FHL tendon is exposed after the deep fascia is split. B. The flexor retinaculum is split to expose the FHL distally. (continued)

   

   

  The tendon is brought posteriorly and positioned at the calcaneus between the two limbs of the remaining débrided Achilles insertion (TECH FIG 2D-F).

   

  If more length of the FHL is needed, the origin of the more distal muscle fibers of the FHL can be detached bluntly from the fibula and interosseous ligament to increase the excursion of the FHL.

   

  Proper tensioning of the FHL transfer is determined by dorsiflexing the ankle to place the Achilles tendon at maximal stretch. With the FHL appropriately tensioned, any excess length of the tendon is removed to allow optimal pull of the transferred tendon to the calcaneus.

   

   

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  TECH FIG 2 • (continued) C. The neurovascular bundle is protected with a deep retractor. D. The FHL is pulled posteriorly and checked for length. E. Drawing of FHL placement between the limbs of the remaining Achilles tendon. F. The FHL is tightly positioned against the Achilles tendon.

• Securing the Tendon

 

The transferred tendon is held with a two-strand suture anchor (TECH FIG 3A).

 

The first strand of suture is used in modified Kessler fashion to secure the FHL to the calcaneus at the proper tension (TECH FIG 3B).

 

 

 

TECH FIG 3 • A. Two-strand suture anchor. B. A positioning stitch is applied to the tendon, and appropriate FHL tension is determined. (continued)

 

 

The second strand is used as a whipstitch to add pullout strength (TECH FIG 3C,D).

 

The FHL tendon is sutured to the Achilles tendon in side-to-side fashion with nonabsorbable braided suture (TECH FIG 3E,F).

 

A careful, layered closure of the paratenon, subcutaneous tissue, and skin is performed.

 

 

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TECH FIG 3 • (continued) C. The anchored tendon. D. The FHL is secured with whipstitch. E. The FHL is sutured to the Achilles tendon in side-to-side fashion. F. The FHL shown sutured to the Achilles tendon.

 

 

PEARLS AND PITFALLS

Skin incision ▪ Care must be taken to make a full-thickness incision from the skin to the paratenon

without undermining the soft tissue layer to avoid skin slough.

Achilles ▪ Make sure to excise all diseased Achilles tendon to reduce the risk of persistent

tendon pain postoperatively. débridement

FHL harvest ▪ Protect the neurovascular bundle with a deep retractor through the medial incision

while exposing the FHL for transfer to avoid injuring adjacent vital structures.

 

 

	Cut the tendon with a no. 15 blade medial to lateral to avoid injury to the neurovascular bundle. Maximally plantarflex the ankle and great toe and pull on the FHL before cutting the tendon to obtain adequate length of the transferred tendon.     FHL transfer ▪ Dorsiflex the foot while placing the FHL transfer at maximal stretch to determine the proper insertion point and tensioning of the transferred tendon. Make sure there is good apposition between the FHL and remaining Achilles tendon by excising all interposed fat and using nonabsorbable sutures to hold the repair.     Skin closure ▪ Perform careful, separate layer closure, starting with the paratenon, to avoid excessive scarring.

 

 

 

POSTOPERATIVE CARE

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A compressive dressing with splints is applied in the operating room with the ankle in neutral position. The initial dressing is kept in place for 10 to 14 days. At that time, if the incision is well healed and the reconstruction was deemed stable at the time of operation, the patient is placed in a controlled ankle motion (CAM)-soled walker and weight bearing as tolerated is allowed.

 

If more than 75% of the Achilles tendon has been débrided, a weight-bearing cast is applied for 4 weeks to provide extra support for the healing tendon.

 

Range-of-motion and strengthening exercises are begun 6 to 8 weeks postoperatively if clinical improvement (decreased pain and swelling) is evident.

 

The patient is weaned from the CAM-soled walker at 10 to 12 weeks as symptoms of pain and swelling allow.

OUTCOMES

Hansen reported a proximal FHL transfer technique with good or excellent results. Emphasis was placed on thoroughly excising the diseased tendon.

Wapner et al reported good to excellent pain relief and improved function in seven patients with Achilles débridement and FHL transfer harvested from the midfoot for tendinosis.

Wilcox et al, using the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score and the SF-36 Health Survey, reported overall good results with FHL transfer in 20 patients with recalcitrant Achilles tendinosis but found that patient function may not improve.

Den Hartog reported significant improvement in the postoperative AOFAS hindfoot scores in 29 patients who underwent FHL transfer for severe Achilles tendinosis.

 

 

COMPLICATIONS

Rerupture of the augmented Achilles

Wound necrosis secondary to undermining of soft tissues

 

 

Infection

Scarring secondary to inadequate repair of the paratenon Persistent pain and swelling

 

 

SUGGESTED READINGS

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2. Cottom JM, Hyer CF, Berlet GC, et al. Flexor hallucis tendon transfer with an interference screw for chronic Achilles tendinosis: a report of 62 cases. Foot Ankle Spec 2008;1(5):280-287.

    

    

3. Coull R, Flavin R, Stephens MM. Flexor hallucis longus tendon transfer: evaluation of postoperative morbidity. Foot Ankle Int 2003;24:931-934.

    

    

4. Den Hartog BD. Flexor hallucis longus transfer for chronic Achilles tendinosis. Foot Ankle Int 2003;24:233-237.

    

    

5. Den Hartog BD. Use of proximal flexor hallucis longus transfer in severe calcific Achilles tendinosis. Tech Foot Ankle Surg 2002;1:145-150.

    

    

6. Elias I, Raikin SM, Besser MP, et al. Outcomes of chronic insertional Achilles tendinosis using FHL autograft through single incision. Foot Ankle Int 2009;30(3):197-204.

    

    

7. Hansen ST. Trauma to the heel cord. In: Jahss MH, ed. Disorders of the Foot and Ankle, ed 2. Philadelphia: WB Saunders, 1991:2357.

    

    

8. Mann RA, Holmes GB Jr, Seale KS, et al. Chronic rupture of the Achilles tendon: a new technique of repair. J Bone Joint Surg Am 1991;73(2):214-219.

    

    

9. McGarvey WC, Palumbo RC, Baxter DE, et al. Insertional Achilles tendinosis: surgical treatment through a central tendon splitting approach. Foot Ankle Int 2002;23:19-25.

    

    

10. Puddu G, Ippolito E, Postacchini F. A classification of Achilles tendon disease. Am J Sports Med 1976;4:145-150.

     

     

11. Rahm S, Spross C, Gerber F, et al. Operative treatment of chronic irreparable Achilles tendon ruptures with large flexor hallucis longus tendon transfers. Foot Ankle Int 2013;34(8):1100-1110.

     

     

12. Schepsis AA, Leach RE. Surgical management of Achilles tendinitis. Am J Sports Med 1987;15:308-315.

     

     

13. Turco VJ, Spinella AJ. Achilles tendon rupture—peroneus brevis transfer. Foot Ankle 1987;7:253-259.

     

     

14. Wapner KL, Pavlock GS, Hecht PJ, et al. Repair of chronic Achilles tendon rupture with flexor hallucis longus tendon transfer. Foot Ankle 1993;14:443-449.

     

     

15. Watson AD, Anderson RB, Davis WH. Comparison of results of retrocalcaneal decompression for retrocalcaneal bursitis and insertional Achilles tendinosis with calcific spur. Foot Ankle Int 2000;21:638-642.

     

     

16. Wilcox DK, Bohay DR, Anderson JG. Treatment of chronic Achilles tendon disorders with flexor hallucis longus transfer/augmentation. Foot Ankle Int 2000;21:1004-1010.

     

     

17. Will RE, Galey SM. Outcome of single incision flexor hallucis longus transfer for chronic Achilles tendinopathy. Foot Ankle Int 2009;30(4):315-317.

     

     

18. Young A, Redfern DJ. Simple method of local harvest and fixation of FHL in Achilles tendon reconstruction: technique tip. Foot Ankle Int 2008;29(11):1148-1150.