Insertional Tendinopathy of the Achilles Tendon

13 Insertional Tendinopathy of the Achilles Tendon

Murali K. Sayana and Nicola Maffulli

Introduction affected tendons has confi rmed degeneration or infl ammation.7 Although insertional tendinopathy of the Achilles tendon is still often Posterior heel pain can be caused by insertional described as “true infl ammation” within the tendinopathy of the Achilles tendon, retrocalca- tendon,6 the histology from 21 recalcitrant calcifi c neal bursitis, Haglund’s deformity, or pretendon insertional Achilles tendinopathy patients showed bursitis. Insertional tendinopathy of the Achilles fi brocartilaginous or calcifying degeneration close tendon, retrocalcaneal bursitis, and Haglund’s to the area of calcifi c tendinopathy. There was deformity, the prominent posterosuperior calca- disorganization of the tendon substance with neal process, constitute the Haglund’s triad. no evidence of intratendinous infl ammatory The exact incidence of Achilles insertional ten- reaction.8 dinopathy is unclear. On the one hand, it is reported as the most common form of Achilles tendinopathy in athletes presenting to outpatient clinics.1 On the other hand, 5–20% of the Achilles Histology tendinopathies were insertional.2,3 Insertional Achilles pathology was seen in 24.7% of 432 The osteotendinous junction of the Achilles chronic Achilles overuse injury patients. Of these, tendon is made up of bone, fi brocartilage, and 5% (21 patients) had pure insertional tendinopa- tendon. The type II collagen distribution in sagit- thy, and 20% (86 patients) had calcaneal bursitis tal sections of the Achilles tendon has been used alone or in combination with insertional tendi- to reconstruct the three-dimensional (3D) shape nopathy.2 Thus, insertional tendinopathy of the and position of three fi brocartilages (sesamoid, Achilles tendon seems to present more often as a periosteal, and enthesis) associated with its inser- triad rather than as a solitary pathology. In another tion.9 Close correspondence between the shape surgical and histopathological survey of 163 and position of the sesamoid and periosteal fi bro- patients with chronic Achilles tendinopathy, cartilages was noted. The former protects the insertional tendinopathy of the Achilles tendon tendon from compression during dorsifl exion of had a prevalence of 20%.4 Insertional tendinopa- the foot, and the latter protects the superior thy is often diagnosed in older, less athletic, and tuberosity of the calcaneus. Complex interlocking overweight individuals as well as in older between calcifi ed fi brocartilage and bone at the athletes.5,6 insertion site was noted on the 3D reconstruc- The triad of pain, swelling (diffuse or localized), tions, which used the zone of calcifi ed enthesis, and impaired performance constitutes ten- fi brocartilage and the subchondral bone. This dinopathy. The suffi x osis or itis should be used interlocking is of fundamental importance in only after histopathological examination of the anchoring the tendon to the bone.

121 122 M.K. Sayana and N. Maffulli

Histopathology Abnormal Anatomy

A tight Achilles tendon, hyperpronation, pes Merkel et al.used light and electronic microscopy, cavus, and obesity can predispose to degenera- and enzyme histochemistry to study 11 insertional tion, attrition, mechanical abrasion, and chemical tendinopathy (including two Achilles tendons) 10 irritation that could lead to a chronic infl amma- specimens. Edema, mucoid degeneration, dis- tory response at the heel.5 ruption of collagen bundles, necroses, small hem- orrhages, and calcifi cation were noted in these specimens. Acid mucopolysaccharides may be Strain Shielding present in lake-like accumulations between collagen fi bers, in contrast to neutral collagens seen in The anterior portion of the Achilles tendon is aging. Small bony particles lay within the carti- affected by the insertional tendinopathy. Lyman laginous portion of the insertion. Also, there were et al.12 studied the in vitro strain behavior of the areas with proliferating blood vessels within Achilles tendon and noticed relative strain shield- tendon tissue with lymphocytes and histiocytes ing of this portion of the tendon, suggesting a role suggesting a reparative process. There was for repetitive tensile loads in the causation of increased activity of NADP-diaphorase, LDH, β- insertional tendinopathy of Achilles tendon. glucuronidase, and alkaline phosphatase. Elec- These fi ndings may explain the variable response tron microscopy showed marked submicroscopic following measures aimed at decreasing tensile calcifi cation and fi brillar degeneration. loads on the tendon. Calcifi c insertional tendinopathy samples har- vested from an area proximal to the insertion on the calcaneus have increased levels of type II and Stress Shielding III collagen and decreased levels of type I colla- A distinct tendency to develop cartilage-like and/ gen. Periodic acid Schiff staining showed the con- or atrophic changes on the stress-shielded side of stant presence of chondroitin sulphate, suggesting the enthesis as a response to the lack of tensile a metaplastic change of the distal portion of the load was noted.13,14 Over long periods, this process Achilles tendon in calcifi c insertional tendinopa- may induce a primary degenerative lesion in that thy (unpublished data). area of the tendon. Thus, tendinopathy is not always activity-related, but can be correlated with age, suggesting that insertional tendinopathy Etiopathophysiology would result from stress shielding rather than overuse injury.15 Repetitive Traction Forces

The etiological factors implicated in Achilles Overuse Injury on a Weak Tendon insertional tendinopathy have traditionally been overuse and poor training habits. Gradual repeti- The cartilage-like changes at the enthesis can be tive traction force leads to spur formation and considered a physiological adaptation to the com- calcifi cation at the Achilles tendon insertion. pressive loads. However, even cartilaginous meta- Enthesophyte formation in rats was compared plasia may not allow the tendon to maintain its with human specimens by Benjamin et al.11 Bony ability to withstand the high tensile loads in that spurs can develop in the Achilles tendon by endo- region. In athletes, certain joint positions may chondral ossifi cation of enthesis fi brocartilage. place high tensile loads on the enthesis. As the There is no need for preceding microtears or stress shielding may have led to tensile weakening infl ammatory reactions to cause insertional Achil- over time, an injury may occur more easily in this les tendinopathy. The increased surface area at region. In this manner, insertional tendinopathy the tendon–bone junction may be an adaptive could be considered an overuse injury, but with mechanism to ensure the integrity of the interface predisposition caused by preexisting weakening in response to increased mechanical loads. of the tendon. 13. Insertional Tendinopathy of the Achilles Tendon 123

Thermal Injury process fracture, fl exor hallucis longus tendinopathy, peroneal tendinopathy, tibialis posterior Strain in one section of the tendon could produce tendinopathy, deltoid ligament sprain, and changes in the opposite section, as a tendon moves osteochondral lesions of talus are some of the the joint. Cellular and/or matrix components of local conditions that may have a similar presenta- the tendon could be injured by the internal shear 16 tion as insertional tendinopathy of Achilles forces, and heat could be generated. Intratendi- tendon. nous degeneration seen in tendinopathy could be due to accumulation of these injuries. Investigations Clinical Features Blood tests for biochemistry and immunology will either confi rm or rule out conditions Early morning stiffness, pain at the insertion of such as gout, hyperlipidemia, and seronegative the Achilles tendon that deteriorates after exercise spondyloarthropathy. or climbing stairs, running on hard surfaces, or Imaging (MRI scan and US scan) can help to heel running are the typical features of Achilles confi rm the diagnosis and identify the extent of insertional tendinopathy. This pain, which is ini- the lesion if a surgical procedure is being planned. tially intermittent, may later become constant. Radiographs help identify ossifi cation of insertion Patients may also give a history of recent increase of the Achilles tendon or a spur (fi shhook osteo- in training, and poor warmup or stretching tech- phyte) on the superior portion of the calcaneum. niques. Achilles tendon insertion is tender on pal- Radiopacities of the Achilles tendon were classi- pation and is often accompanied by thickening or fi ed into three types by Morris et al. (Table nodularity of the insertion. Range of motion of 13.1):17 the ankle, if limited, is due to painful dorsifl exion of the ankle. Swelling, if present, may be due to accompanying retrocalcaneal bursitis. TABLE 13.1. Radiopacities of the Achilles Tendon Haglund’s deformity, a prominent posterosu- Type I Lesion perior tuberosity of the calcaneum, may also Microtrauma Shoe counter, work-related irritation present as a diffuse swelling or prominence in the Macrotrauma Insertion rupture, blunt trauma posterior heel region. Haglund’s triad is more Tendinopathy Overuse, bursitis, calcaneus shape common than isolated insertional tendinopathy Foot type Cavus, rearfoot varus, plantarflexed first of the Achilles tendon. Hence, the clinical picture metatarsal may be a mixture of the clinical fi ndings described Arthropathy Gout, rheumatoid, Reiter’s, ankylosing spondylitis, diffuse idiopathic skeletal above. Plain radiography can help confi rm the hyperostosis Haglund’s deformity and/or ossifi cation or calci- Metabolic Renal failure, obesity, hyperparathyroidism, fi cation of the Achilles insertion. hemochromatosis Infectious Acute or chronic syphilis Type II Lesion Differential Diagnosis Arthropathy Articular chondrocalcinosis, pseudogout Metabolic Vitamin deficiency Both systemic and local conditions can mimic Type III Lesion symptoms produced by insertional tendinopathy Trauma Burn injury, partial/total tendon rupture of the Achilles tendon. Systemic affections include Postsurgery Primary repair, lengthening, recession gout, hyperlipidemia, sarcoidosis, systemic corti- Ischemia Inherent anatomy costeroids, oral fl uoroquinolones, diffuse idio- Infectious Chronic osteomyelitis pathic skeletal hyperostosis, and seronegative Systemic/metabolic Wilson’s disease, hemochromatosis spondyloarthropathies. Congenital Aperiosteal metaplasia, neural arch deficiency CNS Tabes dorsalis Haglund’s deformity, retrocalcaneal bursitis, os trigonum/posterior impingement, posterior talar Modified from Morris et al. (see reference 17). 124 M.K. Sayana and N. Maffulli

FIGURE 13.1. Plain radiograph demonstrating fishhook osteophyte and Haglund’s deformity.

Type I. Radiopacities at the Achilles insertion or (partial tendon calcifi cation) and IIIB (com- superior pole of the calcaneus. The lesion is plete tendon calcifi cation). present within the tendon, and is attached par- Classifi cation of the Achilles tendon abnormali- tially or completely to calcaneus. Bony changes ties based on ultrasonographic changes at the to the calcaneus are often seen in type I lesions. Achilles tendon insertion was introduced by Insertional tendinopathy of Achilles tendon Paavola et al. (Table 13.2).18 causes type I abnormality (Fig. 13.1). Type II. Radiopacities are intratendinous and are located at the insertion zone, 1–3 cm proximal to the Achilles insertion, and are separated Management from calcaneal surface. Type III. Radiopacities are located proximal to the Success rates of 85% to 95% have been reported insertion zone, upward to 12 cm above the with simple measures like rest, ice, modifi cation insertion zone. Type III is subdivided into IIIA of training, heel lift, and orthoses.5,19 The use of nonsteroidal anti-infl ammatory medications is controversial, given their mechanism of action in TABLE 13.2. Ultrasonographic Classification of Insertional Achilles this condition. They probably only provide anal- Tendon Abnormality gesic effects.20 A randomized controlled trial has Classification Insertional Changes shown no advantage of piroxicam over placebo when combined with an initial period of rest fol- No alteration No calcification. Homogeneous fiber structure in 21 the insertional area. lowed by stretching and strengthening exercises. Mild abnormality Insertional calcification, length 10 mm or less Diclofenac reduced the accumulation of infl am- and thickness less than 2 mm. Homogeneous matory cells only within the paratenon, but pro- fiber structure in the insertional area. vided no biochemical, mechanical, or functional Moderate Insertional calcification, length more than 10 mm benefi ts to the rat Achilles tendon following injury abnormality and thickness less than 2 mm. Slight alterations in the echo structure of tendon when compared with a placebo group. Also, there in the insertional area. was no reduction in the accumulation of neutro- Severe abnormality Insertional calcification, length more than 10 mm phils and macrophages in the core of the or thickness more than 2 mm. tendon.22 Moderate to severe variety in the echo structure Modifi cation of training, and stretching and of tendon in the insertional area. strengthening exercises can also be effective. 13. Insertional Tendinopathy of the Achilles Tendon 125

However, eccentric calf muscle training helped for Achilles insertional tendinopathy with tenoly- only 32% of patients with insertional tendinopa- sis, excision of the bursa, and/or excision of the thy, compared to 89% of patients with noninser- posterosuperior portion of the calcaneum through tional tendinopathy of Achilles tendon.23 In a 10-cm medial incision. The recovery in these athletes, non-weight-bearing activities can help to patients was longer (31 weeks) when compared maintain fi tness until symptoms improve. Immo- with patients with tendinopathy of the main body bilization of the ankle in a below-knee weight- of the Achilles tendon who underwent tenolysis bearing cast or a walker boot can be only (22 weeks), with a success rate of 93%. counterproductive, although suggested by some Calder et al.28 reported only two failures in 49 authors.5,24 Tendon loading stimulates collagen heels, where less than 50% of the tendon was fi ber repair and remodeling. Therefore, complete excised. These ankles had been immediately rest of the injured tendon is not advisable. Ultra- mobilized free of a cast. One patient had psoriatic sound treatment could be benefi cial to control arthropathy, and a second patient underwent symptoms at the insertion site. We do not use bilateral simultaneous procedures. local injections of corticosteroids. Kolodziej et al.29 concluded that superior-to- Sclerosing therapy in insertional tendinopathy inferior resection offers the greatest margin of showed promising results in a pilot study.25 Poli- safety when performing partial resections of the docanol was injected into local neovessels local- Achilles insertion, and as much as 50% of the ized by ultrasound and color Doppler. Eight of 11 tendon may be resected safely, based on a biome- patients experienced good pain relief, and seven chanical study. of them had no neovascularization at a mean McGarvey et al.30 reported the use a midline- follow-up of eight months. The two of the three posterior skin incision combined with a central patients who had poor results had bony spurs. tendon-splitting approach for debridement, ret- Therefore, patients with severe bone pathology rocalcaneal bursectomy, and removal of the cal- and mechanical problems are less suitable for caneal bursal projection as necessary. Twenty of sclerosing therapy.26 22 patients were able to return to work or routine activities by three months. Thirteen of 22 were completely pain free and were able to return to Surgery unlimited activities. Overall, there was an 82% (18 of 22) satisfaction rate with the approach. Surgical options are considered after 3 to 6 months Watson et al.31 reported that retrocalcaneal of conservative management fail to produce sat- decompression in patients with insertional isfactory symptomatic relief. The principles of Achilles tendinopathy with calcifi c spur was less surgery specifi c for this condition are debride- satisfactory when compared with retrocalcaneal ment of the calcifi c or diseased portion of the decompression in patients with retrocalcaneal Achilles insertion, excision of the retrocalcaneal bursitis. bursa, and resection of the Haglund’s deformity, Den Hartog et al.32 reported successful use of if present. Various surgical procedures have been fl exor hallucis longus transfer for severe calcifi c described that adhere to the above principles. Achilles tendinopathy in 26 patients (29 tendons) However, they differ in terms of reconstruction, if in whom conservative treatment failed and who the Achilles tendon is disinserted or extensively also had failed tendon debridement and/or debrided. We prefer to reattach the Achilles Haglund’s resection. These patients were seden- tendon using bone anchors if one-third or more tary, overweight, and had chronic symptoms. The of the insertion is disinserted. Augmentation AOFAS ankle-hindfoot scale improved from 41.7 using tendon transfer techniques have also been to 90.1. The time to maximum recovery was described. approximately 6 months. All patients lost fl exor Anderson et al.27 studied the surgical manage- strength at the interphalangeal joint of great toe. ment of chronic Achilles tendinopathy in 48 Decompression of the retrocalcaneal space patients including 27 competitive athletes. using a minimally invasive technique was reported Twenty-eight patients (58%) underwent surgery by Leitze et al.33 Indications for this procedure 126 M.K. Sayana and N. Maffulli were patients with retrocalcaneal bursitis, mechanical impingement, and/or Achilles insertional tendinopathy, who failed to respond to conservative management. Major calcifi c insertional tendinopathy of the Achilles tendon was considered a contraindication for endoscopic decompression. The advantages included quicker surgery and fewer complications although the recovery time was similar to open decompression.

FIGURE 13.2 Incision: 1 cm medial to the medial border of the Authors’ Preferred Surgical Method lower one-third Achilles tendon.

Patients are operated under general anaesthesia, with a thigh tourniquet infl ated to 250 mmHg their normal shining appearance, and palpated after exsanguination of the limb. A longitudinal for areas of softening or thickening. These areas incision, 1 cm medial to the medial border of the are explored via one to three longitudinal tenoto- Achilles tendon, is extended from the lower one- mies, and areas of degeneration are excised and third of the tendon to up to 2 cm distal to its cal- sent for histology. The longitudinal tenotomies caneal insertion (Fig. 13.2). The incision can be are not repaired. The area of calcifi c tendinopathy extended transversely and laterally in a hockey- is identifi ed and edges defi ned using the tip of a stick fashion, if necessary. A Cincinnati-type inci- syringe needle (Fig. 13.4). The calcifi c area is then sion could also be used. The Achilles tendon is exposed starting from its proximal and medial exposed and sharp dissection is continued to the aspect. Most patients will have at least one-third paratenon, which is dissected from the tendon of the Achilles tendon surrounding the area of and excised, taking care to preserve the anterior calcifi c tendinopathy detached by sharp dissec- fat in Kager’s triangle and not to injure the meso- tion, and occasionally total disinsertion of the tenon (Fig. 13.3). The retrocalcaneal bursa is Achilles tendon is necessary. The area of calcifi c excised, if there is evidence of bursitis. The Achil- tendinopathy is excised from the calcaneus les tendon is inspected for areas that have lost (Fig. 13.5).

FIGURE 13.3 Deeper dissection. 13. Insertional Tendinopathy of the Achilles Tendon 127

FIGURE 13.4 Calcified areas being probed with needle.

The area of hyaline cartilage at the posterosu- used if 75% or more of the Achilles tendon is dis- perior corner of the calcaneus may be macroscop- inserted, and ﬁ ve bone anchors are used if the ically degenerated. In this instance, it is excised Achilles tendon had been totally disinserted. The using an osteotome and, if needed, its base paired Achilles tendon is advanced in a proximal to distal off using bone nibblers. The tendon is reinserted fashion and reinserted in the calcaneum (Fig. in the calcaneus using bone anchors (Figs. 13.6 13.8). We do not usually perform a tendon aug- and 13.7). Two bone anchors are used if one-third mentation or a tendon transfer. After release of to 50% of the Achilles tendon is disinserted. Three the tourniquet, hemostasis is achieved by dia- bone anchors are used if 50% to 75% of the Achil- thermy. The wound is closed in layers using les tendon is disinserted. Four bone anchors are absorbable sutures (Figs. 13.9 and 13.10).

FIGURE 13.5 Disinserted Achilles tendon and Haglund’s deformity. 128 M.K. Sayana and N. Maffulli

FIGURE 13.6 Haglund’s deformity is excised, and drill holes are made to receive bone anchors.

FIGURE 13.7 Bone anchors in situ. 13. Insertional Tendinopathy of the Achilles Tendon 129

FIGURE 13.8 Achilles tendon being reinserted.

FIGURE 13.9 Line diagram of the surgical wound after subcuticular closure.

FIGURE 13.10 Postoperative radiograph with bone anchor in situ. 130 M.K. Sayana and N. Maffulli

Postoperative Management et al., using the 4-point functional scale validated for evaluation of long-term results following The skin wound is dressed with gauze, and sterile surgery for tendinopathy. Eleven patients reported plaster wool is applied. A synthetic below-knee an excellent result and fi ve a good result. The cast with the ankle plantigrade is applied. Patients remaining fi ve patients could not return to their normal levels of sporting activity and kept fi t by are discharged home on the day of surgery, after 8 mobilizing with crutches under the guidance of a alternative means. physiotherapist. Patients are advised to bear weight on the operated leg as tolerated, but are told to keep the leg elevated as much as possible Discussion for the fi rst 2 postoperative weeks. After 2 weeks, the cast is removed. A synthetic Signifi cant progress has occurred in our under- anterior below-knee slab is applied, with the ankle standing of Achilles insertional tendinopathy in neutral, and secured to the leg with three or since Clain and Baxter classifi ed Achilles tendon four removable Velcro straps for 4 weeks. The disorders into noninsertional and insertional ten- patients are encouraged to continue to bear weight dinopathy in 1992.34 Insertional tendinopathy of on the operated limb and to gradually progress to the Achilles tendon is a degenerative rather than full weight bearing, if they are not already doing an infl ammatory lesion, though the accompany- so. A trained physiotherapist supervises gentle ing bursitis may paint an infl ammatory picture. mobilization exercises of the ankle, isometric con- The true incidence of Achilles insertional ten- traction of the gastrosoleus complex, and gentle dinopathy is still not clear. Incidence varies from concentric contraction of the calf muscles. Patients 5% to the most common presentation of Achilles are encouraged to perform mobilization of the tendon in athletes. Insertional tendinopathy of involved ankle several times per day after unstrap- the Achilles tendon is distinct from retrocalcaneal ping of the relevant Velcro strap(s). bursitis and Haglund’s deformity, and can coexist After 6 weeks, the anterior slab is removed. Sta- with them. Further epidemiological studies are tionary cycling and swimming are recommended needed with a clear terminology to identify the from the second week after removal of the cast. true incidence of this problem. We allow return to gentle training 6 weeks after Presence of type II and III collagen, chondroid removal of the cast. Gradual progression to full metaplasia, and decreased type I collagen was sports activity at 20 to 24 weeks from the opera- found in histological specimens proximal to the tion is planned according to the patients’ prog- Achilles insertion in insertional tendinopathy. ress. Resumption of competition will depend on Type I collagen contributes to the tensile strength the patients’ plans, but is not recommended before in tendons, allowing them to resist force and 6 months after surgery. tension and to stretch. Therefore, tendons with an Patients are reviewed at 3, 6, and 9 months from increased type III and a reduced type I collagen the operation, and at 6-month intervals thereaf- content are less resistant to tensile stresses. ter. Further physiotherapy along the lines The in vitro biomechanical studies on the distal described above is prescribed if symptoms are still Achilles tendon have produced new insight into present, and the patients are followed up until possible etiologies. Eccentric calf muscle training they have improved and are therefore discharged, is not benefi cial in Achilles insertional tendinopa- or need further surgery. thy.23 This reiterates the fact that the management We operated on 21 patients with recalcitrant strategies should be different in insertional and calcifi c insertional Achilles tendinopathy who noninsertional tendinopathies of Achilles tendon, underwent bursectomy, excision of the distal as their etiologies are likely to be different. In vitro paratenon, disinsertion of the tendon, removal of strain studies on the distal Achilles tendon have the calcifi c deposit, and reinsertion of the Achilles identifi ed that the anterior portion of the Achilles tendon with bone anchors. The outcome of surgi- insertion is stress shielded or is underused. This cal management was rated according to Testa stress-shielded area could be a site for primary 13. 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