Introduction

Pain in the area of the posterior calcaneus may have different causes, such as paratendenitis, insertional tendeninitis of the Achilles tendon, apophysitis calcanei, retrocalcaneal bursitis and a “Haglund” exostosis [4, 5, 11, 19, 20, 23, 26, 33, 34]. In 1928, the Swedish orthopaedic surgeon Patrick Haglund described a syndrome of a painful hindfoot with a prominence of the calcaneal tuberosity and a massive callus, which was caused by a rigid heel counter [9]. Since then a painful bony prominence of the dorsal and lateral part of the calcaneus is named Haglund’s syndrome or disease. Haglund’s syndrome is often observed bilateral, mostly at the end of the 2nd or the 3rd decade, and mainly in females. The diagnosis is usually based on the patients’ complaints and the results of clinical and radiological examination. A hindfoot varus and a pes cavus are both predisposing factors for heel pain due to the vertical position of the calcaneus. However, its also common among athletes where a joint-like surface found at the superior calcaneus with contact to the Achilles tendon, and the bursitis is caused by repeated overuse and the bony hypertrophy as the consequence of external pressure [4].

Conservative treatment of clinical symptoms includes local corticosteroid injection, NSAIDs, and ultrasound waves [21], elevation of the heel with a heel cushion and footwear without heel counter are also indicated. However, conservative treatment even over months may some times not be effective in some cases and shows a high recurrence rate [18, 35, 38].

Many authors proposed the surgical treatment after failure of conservative measures. This surgical intervention was in the form of open resection calcaneoplasty of the dorso-lateral part of the calcaneus up to the insertion of the Achilles tendon. But the results after open resection of the calcaneal exostosis are not always satisfying [18, 27, 28, 30, 32, 35]. The endoscopic approach for this entity was first described by Van Dijk et al. [36].

As an alternative to the open procedure, we perform the endoscopic calcaneoplasty (ECP). The purpose of this study was to present our surgical technique, our findings and clinical results of ECP.

Materials and methods

Between 1999 and 2005, we indicated and performed ECP in 81 patients. The age of these patients range between 25 and 55 years, we treated 40 males and 41 females. All patients were referred to our unit with posterior heel pain, which did not respond to conservative treatment for at least 6 months.

The hindfoot had a normal alignment, in patients with a varus foot, surgery was not indicated. All patients had a preoperative lateral view X-ray of the ankle that demonstrated a dorso-posterior calcaneal exostosis.

All patients underwent a test of injection of local anaesthesia in order to proof the presence of a retrocalcaneal bursitis and surgery was only indicated, if this test temporarily relieved the symptoms.

Surgical technique: ECP was performed in the supine position (except the first ten cases, which where operated in prone position) under epidural or general anaesthesia. A tourniquet was applied at the thigh. An intraoperative radiographic control was only used in the first ten cases. With gaining more experience, the insertion area of the Achilles tendon can easily be identified endoscopically.

We used the supine position in the operation, where the affected foot was positioned over the distal rim of the operating table so that the area of interest could be reached from both sides and be moved freely. Flexion and extension was controlled by the surgeon’s body, so that adjustment of the dorsiflexion in the ankle joint could be achieved. With this technique, both hands were free for the instruments and the arthroscope. The contra-lateral leg was slightly flexed and abducted on the table so that no interference with the operating-field occurred.

The initial approach can be chosen lateral or medial. For establishing the initial portal, a needle is placed directly at the upper rim of the posterior and superior tip of the calcaneus (Fig. 1). In the first five cases, fluoroscopic control was used in order to establish the initial portal. The area of insertion of the Achilles tendon is not jeopardized by our approach, because the insertion of the Achilles tendon is much more distal. A small vertical incision of the skin was performed and the subcutaneous tissue was spreaded by a blunt dissector. We used the 4 mm arthroscope that was positioned in the retrocalcanal space. With some experience, it was possible to perform the operation without fluoroscopy. Under direct endoscopic control, the contralateral approach is created in the Wissinger technique (inside out).

Fig. 1
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Placement of the needle for marking the approach

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At first, the frequent existing inflamed retrocalcaneal bursa was identified and resected with a 4-mm resector (Fig. 2). For the resection of the bursa, fibrous tissue and periostium a bipolar resection device (VAPR; Mitek) was very useful, as less bleeding is expected than happens with traditional shaver and no debris left behind. However, the permanent use of a bipolar resection device has to be avoided, because the small fluid volume is heated very fast, which can lead to a damage to local tissue as well as the skin.

Fig. 2
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Retrocalcaneal bursitis

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After the local debridement, the Achilles tendon is localized and prepared. The surface of the calcaneus opposite to the Achilles tendon shows regularly a cartilage-like coating. This is abraded; at the same time the posterior gutter is cleaned. Afterwards, the calcaneal exostosis is exposed (Fig. 3) and resected with the 4-mm burr (Fig. 4). The resection starts at one edge (medial or lateral) and is completed after changing the portals.

Fig. 3
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Preparation of the exostosis

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Fig. 4
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Osseous resection of the exostosis with a burr

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The insertional area of the Achilles tendon is clearly located distally to the exostosis and can nicely be exposed with some experience (Fig. 5). It is important to detect the course of the Achilles tendon fibres and their calcaneal insertion in order not to injury it.

Fig. 5
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Distal insertion of the Achilles tendon

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The arthroscopic and the instrument portals should be used in the interchangeable manner for the endoscope and the burr in order to obtain a total bony resection. During the whole procedure the Achilles tendon is protected by the closed side of the burr tip. Finally loose tissue, bony debris and remaining rims are carefully removed with the synovial resector for prevention of heterotopic ossification.

There is no need to place a drain. If a drain is used, this should not be a suction drain, because this will lead to a significant blood loss up to 250–350 ml from the cancellous bone of the calcaneus. The skin is closed and a compressive dressing is placed on both sides of the Achilles tendon. Postoperatively elevation of the foot for the first 5 days is recommended. After partial weight bearing for 2 weeks an increasing full weight bearing is allowed. Normal footwear should not be used for 6 weeks and no athletic activities for at least 12 weeks.

Results

The average follow-up was 35.3 months (12–72). The documentation and differentiation of local findings during ECP showed the following.

In 22 cases, a yellowish alteration in the area of Achilles tendon insertion (Fig. 6) was documented, which was histologically described as a chondroid metaplasia (Fig. 7). It is remarkable that the insertion of the Achilles tendon is shaped like a fan and takes hold of the calcaneus in basket like configuration (Fig. 8). The insertion of the deep fibres in the posterior aspect of the calcaneus is far distal and can endoscopically be well explored (Fig. 9).

Fig. 6
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Yellowish alterations of achilles tendon

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Fig. 7
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Chondroid metaplasia (HE-staining)

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Fig. 8
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Fan-like insertion of the achilles tendon, in cadaver

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Fig. 9
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Distal insertion of the achilles tendon at the calcaneus

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In 32 patients, a preoperative MRI-scan was performed and in 25 patients a retrocalcaneal bursa with cranial protrusion was found (Fig. 10). Conspicuous was in some cases an intratendinous increased signal in the Achilles tendon (Fig. 11) or the indication of a partial rupture at the insertion of the tendon (Fig. 12). These ruptures were confirmed endoscopically (Fig. 13). The partial tears of the Achilles tendons regularly showed significant substantial defects. In two patients, a technetium scan was performed before surgery. They presented a higher uptake in the area of the Haglund exostosis (Fig. 14).

Fig. 10
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Enlarged retrocalcaneal bursa in the MRI

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Fig. 11
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Retrocalcaneal bursa with marked intratendinous signal of achilles tendon

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Fig. 12
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MRI shows subtotal rupture of the distal insertion of the achilles tendon

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Fig. 13
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Endoscopical image of partial ruptured achilles tendon

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Fig. 14
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Nuclear medinical technetium uptake in Haglund exostosis

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The mean operating time was 46 min in the first ten cases (28–84 min). With increasing the learning curve of ECP was quite short in our hands; the mean operating-time for the following cases was only 25 min (14–42 min).

The clinical examination was performed by using the Ogilvie–Harris–Score [2], in which several parameters were documented. This score was chosen for comparing the results with other references [37]. Thirty-four patients presented good and 41 patients excellent results, while three patients showed fair results, and three patients only poor results.

The three patients with the poor results showed an ossified area of the Achilles tendon insertion (Fig. 15). These three patients (two males and one female) were revised in an open procedure. Via a dorsal approach, the ossifications were removed by tendon splitting. The tendon was fixed with two bone anchors and non-resorbable sutures (Fig. 16).

Fig. 15
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Intertendinous ossification as reason for continuous pain after ECP

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Fig. 16
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Postoperative radiograph after removal of intratendinous ossifications and refixation of the achilles tendon by the use of bone anchors with non resorbable sutures

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In 76 of the 81 cases, the postoperative radiographs showed that the intended bony resection was achieved by the ECP (Fig. 17a, b). After 2 days only a minimal swelling was found (Fig. 18).

Fig. 17
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a, b Pre- and post-operative radiographs after ECP

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Fig. 18
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Clinical appearance 2 days after ECP

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Due to the small portals, the quick subjective satisfaction and minimal postoperative pain some patients began with early weight bearing against our advice. Some of these patients developed a painful local swelling which was then permanent for several weeks. In two cases, the total recovery time was 12 weeks. Therefore, we strictly recommend the use of crutches for partial weight bearing for 2 weeks.

Neither neurovascular nor intra- or postoperative complications were observed. In one of the first cases, a superficial inflammation of the skin was found at the 2-week control which was caused obviously by the heatened irrigation fluid. After 6 weeks, the inflammation was not evident any more. Using a bipolar device in ECP, a high fluid flow should be guaranteed and the time of using a bipolar device should be minimized. Mechanical instruments should be favoured.

Discussion

Haglund syndrome is a common cause of posterior heel pain. This pain is characterized clinically by a painful soft tissue swelling at the level of Achilles tendon insertion, tenderness at the Achilles tendon insertion, and pain on active and passive dorsal and plantar flexion movements [11, 38]. With the radiologic and arthroscopic comparisons, the osseous prominence is smaller than in the real clinical appearance due to the cartilaginous cap. Additionally, the lateral angle between plantar and posterior border of the calcaneus is in an obtuse and not a normal tapered angle (<69°) [31].

In our experience, patients who did not respond to conservative treatment for about 6 months went into a surgical solution, and this matches with the literature [12, 30, 38]. The supine position was used except for the first few cases, as it is easier in handling of the foot during the operation; moreover, it is safe with a better orientation of the inside structures for the surgical beginners. This actually matches with Van Dijk experience in 2006 [37].

The open procedure with resection of the calcaneal spur and the bursa for the operative treatment of the posterior heel pain was described by many authors [20, 30, 32, 35]. In the open procedure, the surgical principle is first to achieve a complete exposure of the anatomic site and to perform the resection without weakening the insertion of the Achilles tendon. The same can be endoscopically achieved. In the literatures different approaches are mentioned, most of them agreed that the resection is possible by an incision 1.0 cm medial and longitudinal along the Achilles tendon, which can be prolonged in a j-like shape [34]. Other authors prefer bilateral longitudinal incisions next to the Achilles tendon to remove the bony prominence carefully with a curette and a rongeur so that no prominent bony parts were left behind the Achilles tendon [19]. As an alternative a direct midline incision, 2.0 cm proximal the insertion of the Achilles tendon up to 4.0 cm prolonged distal to the insertion was recommended, this was followed by a complete central split of the tendons over the whole skin incision length. At least a debridement of inflammatory or necrotic tissue as well as the removal of bony tissue is performed [27,34]. Endoscopically a bilateral medial and lateral approach is necessary in order to reach and remove all parts of the bony Haglund exostosis.

The results after open Haglund resection and bursectomy are varying. In patients with posterior heel pain resection of the posterior–superior part of the calcaneus and removal of the degenerative and calcified soft tissue leads to good clinical results about 76% [5, 20, 27]. Other authors found after bony resection and bursectomy an improvement of the symptoms in only 69% of the patients [35]. In our hand ECP showed good and excellent results in more than 90% of the patients.

After open surgery, different complications such as skin lesions [1], lesions of the Achilles tendon [22], weakness of the calcaneus after removing the posterior–superior bony part [32], persisting pain [28], colloid transformation and irritation of the scar [24], hypesthesia in the area of the scar [30] and irritation of the total heel [28] were reported.

After the open procedure, a splint is advised for 2 weeks followed by a stepwise progression in weight bearing over 4 weeks. The stretched tendon should not be exposed to excessive tension by stretching (e.g., deep crouching, jumping forces) for 12 weeks.

In the open technique, the extensive exposition of the surgical site is not simple in spite of the superficial operation field. This is the reason for so many different approaches for the retrocalcaneal space, which demonstrates partly the clinical problems in the surgical treatment of the calcaneus exostosis. Most authors underline the importance of an extended conservative treatment and restrict indication for open surgery.

From the anatomic view, the Achilles tendon inserts at the posterior aspect of the calcaneus [8], where a retrocalcaneal bursa separates the tendon from the calcaneus [20, 23]. This correlates well with the intraoperative endoscopical aspect. Histological examinations of the bursa show in the anterior part, which fits tightly to the calcaneus, a fibrous cartilaginous tissue; this can also well be documented during calcaneoplasty. In the posterior part, which is related to the Achilles tendon an epitenon is described, which cannot be distinguished from the tendon itself [7]. Biomechanic studies an increasing pressure on the retrocalcaneal bursa during dorsiflexion of the foot and a decrease of the pressure in plantarflexion. Thus, the main function of the bursa is a spacer between the axes of the ankle joint and the Achilles tendon [3, 33]. The anatomical shape of the superior tuberosity of the calcaneus is variable and reaches from hyperconvex to normal up to hypoconvex [26]. In the lateral radiologic view described the calcaneus as the anatomic reference point [11, 31]. The assessment of this bone and the biomechanic of the foot can be performed best in the lateral projection [2, 31], where the posterior calcaneal angle can be measured according to Fowler and Philip [6]. An angle above 75° is significant for a Haglund exostosis. The correlation of radiological appearance and clinical symptoms is more evident if a combination of calcaneal angle and the inclination of the talus are measured, thus a combined angle more than 90° is significant for a Haglund exostosis [33]. In addition, this varus deformity significantly may increase this problem [36], that is why we excluded patients with varus or cavus from our work.

Our experience also showed that one should avoid calcaneoplasty in patients with bone formation within the distal Achilles tendon insertion. This entity is most probably an enthesiopathy of the tendon, which cannot be treated endoscopically. For these patients, we suggest a posterior longitudinal incision and by a split of the Achilles tendon. After resection the bone formation, the tendon needs bony reattachment, which can be achieved by transosseous sutures or bone anchors.

The calcaneal angle is reduced by elevating of the heel and the forward gliding in the shoe [11] and the calcaneus loses its contact to the heel of the shoe which leads to pain reduction. The bursitis usually is of idiopathic origin, but some authors [10, 12] advise laboratory tests to exclude the manifestation of a rheumatoid arthritis and gout.

Conservative treatment includes the avoidance of sturdy shoes, modification of activities, the use of cushions, pads for elevation of the heel and stretching and strengthening of the gastrocnemius–soleus complex [34]. Use of NSAIDs and injection of corticoids in the retrocalcaneal bursa are also recommended, but the direct intratendinous steroid injections may weaken the tendon for at least 14 days, which may lead under some circumstances to a rupture of the tendon later on [21]. After the unsuccessful conservative treatment for more than 6 months surgical treatment may be indicated [1, 11, 12, 30].

Both the open bursectomy and resection of calcaneal exostosis as well as the ECP allow direct visualisation of the ankle joint. Possible advantages of ECP seem to be the reduced morbidity and postoperative pain, earlier suitable rehabilitation and the possibility for ambulant care [13–16].

Smaller arthroscopic approaches are combined with a lower rate of complications of wound and soft tissue healing problems. Our own results showed that, typical complications, which are related to open procedure, could be avoided. And this matches with the experience of other authors [17, 37, 38]. If we compare our experience and results with ECP with the conventional open technique [25, 27, 35], there seem to be less complications, earlier rehabilitation, and the early return of the patients’ to their activities after ECP. Surgeons who are familiar with arthroscopic surgery will soon prefer ECP instead of open Haglund resection.

Conclusion and clinical relevance

The minimal invasive calcaneoplasty is a suitable alternative procedure to the open technique. ECP can achieve reproducible results, allows an excellent differentiation of different pathologies and show less complications than open technique. For the experienced arthroscopist, the learning curve is short.