Minimally invasive surgeries for insertional Achilles tendinopathy: A commentary review

Abstract

Studies of minimally invasive surgery for insertional Achilles tendinopathy are limited. To establish this surgery, the following techniques must be minimally invasive: Exostosis resection at the Achilles tendon insertion, debridement of degenerated Achilles tendon, reattachment using anchors or augmentation using flexor hallucis longus (FHL) tendon transfer, and excision of the posterosuperior calcaneal prominence. Studies on these four perspectives were reviewed to establish minimally invasive surgery for insertional Achilles tendinopathy. Techniques for exostosis resection were demonstrated in one case study, where blunt dissection around the exostosis was performed, and the exostosis was resected using an abrasion burr under fluoroscopic guidance. Techniques for debridement of degenerated Achilles tendon were demonstrated in the same case study, where the space left after resection of the exostosis was used as an endoscopic working space, and the degenerated Achilles tendon and intra-tendinous calcification were debrided endoscopically. Achilles tendon reattachment techniques using suture anchors have been demonstrated in several studies. However, there are no studies on FHL tendon transfer techniques for Achilles tendon reattachment. In contrast, endoscopic posterosuperior calcaneal prominence resection is already established. Additionally, studies on ultrasound-guided surgeries and percutaneous dorsal wedge calcaneal osteotomy as minimally invasive surgery were reviewed.

Core Tip: Studies of minimally invasive surgery for insertional Achilles tendinopathy are limited. Therefore, to establish this surgery, the following techniques must be minimally invasive: (1) Exostosis resection at the Achilles tendon insertion; (2) Debridement of degenerated Achilles tendon; (3) Reattachment using anchors or augmentation using flexor hallucis longus tendon transfer; and (4) Excision of the posterosuperior calcaneal prominence. This article reviewed studies from these four perspectives to establish minimally invasive surgery for insertional Achilles tendinopathy. In addition, studies on ultrasound-guided surgeries and dorsal percutaneous dorsal wedge calcaneal osteotomy as minimally invasive surgery were reviewed.

INTRODUCTION

Insertional Achilles tendinopathy is characterized by exostosis and intra-tendon calcification at the insertion site of the Achilles tendon into the calcaneus[1]. After failing to respond to exhaustive conservative therapy for 3-6 mo, surgery is considered[2,3]. Standard surgical procedures include posterior midline skin incision, calcaneal exostosis resection, partial or total detachment and debridement of the Achilles tendon at its insertion, resection of the posterosuperior calcaneal prominence and retrocalcaneal bursa, and reattachment using anchors or augmentation using flexor hallucis longus (FHL) tendon transfer[4,5]. The surgery’s outcomes have been good[6-29]; nonetheless, the recovery was slow due to the invasiveness and the high complication rate due to the large skin incision[6,29-31]. McGarvey et al[6] reported a case series of 21 patients where 40% had residual pain for over two years postoperatively[6]. Hörterer et al[29] surveyed 118 people who underwent midline incision, partial release and debridement of the Achilles tendon, resection of the posterosuperior calcaneal prominence, and reattachment using anchors. They found that despite the high satisfaction rate, 41% had shoe limitations, and 14% had mild infections[29]. A systematic review by Highlander and Greenhagen[30] reported a 7.0% complication rate for midline incision, and another by Thompson et al[31] reported a significantly higher complication rate for midline incision than other incision techniques. Considering these, minimally invasive surgery is preferable. However, studies on minimally invasive surgery for insertional Achilles tendinopathy are scarce[32].

Therefore, to establish minimally invasive surgery for insertional Achilles tendinopathy, all four steps described below must be performed with minimally invasive surgery (Table 1).

Table 1.

Techniques required in minimally invasive surgery for insertional achilles tendinopathy

No.	Techniques
1	Exostosis resection at the Achilles tendon insertion
2	Debridement of degenerated Achilles tendon
3	Reattachment using anchors or augmentation using FHL tendon transfer
4	Excision of the posterosuperior calcaneal prominence

FHL: Flexor hallucis longus.

This article reviewed studies on the above four techniques, including case reports, cadaver experiments, technical notes, and case series, to establish minimally invasive surgery for insertional Achilles tendinopathy. In addition, reports regarding ultrasound-guided surgeries and percutaneous dorsal wedge calcaneal osteotomy as minimally invasive surgery were also reviewed. In this article, the terms “Haglund disease” and “Haglund syndrome” were avoided because such eponymous terms are unclear[33,34].

ENDOSCOPIC SURGERY FOR INSERTIONAL ACHILLES TENDINOPATHY

Fluoroscopic calcaneal exostosis resection and endoscopic Achilles tendon debridement

In 2022, Nakajima[32] published a case series of 44 patients who underwent minimally invasive surgeries for insertional Achilles tendinopathy involving techniques of exostosis resection at the Achilles tendon insertion and debridement of degenerated Achilles tendon (Table 1)[32]. The outline of this technique included the following: (1) Blunt dissection was performed around the exostosis with fluoroscopic guidance; (2) An abrasion bur was inserted into the space created by the dissection, and the exostosis was resected fluoroscopically; (3) The space left after resecting the exostosis was used as endoscopy working space; and (4) Debridement of the degenerated Achilles tendon was performed endoscopically (Figure 1). The outcome improved based on the median visual analog scale (VAS) and the Japanese society for surgery of the foot scores from 64.5 mm to 6.5 mm and from 67.0 points to 100 points, respectively. The median time to return to sports was 4.5 mo. Furthermore, postoperative magnetic resonance imaging (MRI) revealed that the space left after resecting the exostosis was filled with soft tissue similar to the Achilles tendon, suggesting natural repair of the attachment site (Figure 2)[32]. The novelty of this study is that it allowed exostosis resection at the Achilles tendon insertion and debridement of the degenerative Achilles tendon to be performed with minimal invasiveness. Besides, this case series did not require reattachment or augmentation of the Achilles tendon, as natural repair of the Achilles tendon insertion site was observed. In addition, since there was no preoperative retrocalcaneal bursitis in the cases, resection of the posterior superior eminence was not performed.

Figure 1.

Fluoroscopic and endoscopic calcaneal exostosis resection and Achilles tendon debridement for insertional achilles tendinopathy[32]. A: Blunt dissection around the exostosis. Two portals were created 1 cm proximal and distal from the exostosis (circles), and blunt dissection around the exostosis was performed using a raspatorium; B: Exostosis resection using an abrasion burr under fluoroscopic guidance (arrowhead). Care was taken not to damage the normal insertion of the achilles tendon (circle). The space left after resection of the exostosis was a working space for endoscopy; C: Endoscopic view from the distal portal. The portion of the achilles tendon that had attached to the exostosis was visible as a free end (T). The unresected exostosis was attached to the tendon (arrowhead). The degenerated Achilles tendon was debrided endoscopically; D: Postoperative fluoroscopic view. The exostosis was totally resected (arrowhead). P: Proximal portal; D: Distal portal; C: The calcaneus; T: Free end.

Figure 2.

Pre- and postoperative magnetic resonance imaging of the left calcaneus of a patient with insertional achilles tendinopathy who underwent Fluoroscopic and endoscopic calcaneal exostosis resection and achilles tendon debridement[32]. A: Preoperative magnetic resonance imaging (MRI). Exostosis and intra-tendon ossification were visible (white arrows); B: Postoperative MRI at 9 mo postoperatively. The void space left after resection of the exostosis and intra-tendon ossification was filled with soft tissue providing the same signal as the Achilles tendon, suggesting a natural repair.

Endoscopic Achilles tendon reattachment

Several studies have reported techniques for endoscopic reattachment of the Achilles tendon insertion.

Xu et al[35] published a case series that described a technique for endoscopically repairing partial Achilles tendon tear at the Achilles tendon insertion caused by endoscopic posterosuperior calcaneal prominence resection[35]. A suture anchor was placed at the center of the bone-resected surface after the posterosuperior prominence resection, and two stab wounds were made on the medial and lateral margins of the Achilles tendon, respectively. Afterward, the Achilles tendon was sutured using the modified Bunnel technique through these four stab wounds. They performed this procedure in seven patients with insertional Achilles tendinopathy; five reported excellent results [American orthopedic foot and ankle society (AOFAS) score, 90-100], and two reported good results (AOFAS score, 80-89).

Vega et al[36] also reported a technique similar to that of Xu et al[35] in their case series[36]. An anchor with two sutures (four limbs) was placed at the center of the bone-resected surface after the endoscopic resection of the posterosuperior calcaneal prominence. Two limbs were passed through the medial portion of the Achilles tendon and sutured subcutaneously at the medial portal. The remaining two limbs were similarly sutured at the lateral portal. Twelve patients underwent this surgery, improving their AOFAS score from 70 to 92 and their Victorian institute of sports assessment-Achilles (VISA-A) score from 34 to 92.

Michel et al[37] published a case report of a patient undergoing endoscopic posterosuperior prominence resection and endoscopic Achilles tendon repair for retrocalcaneal bursitis with partial Achilles tendon rupture[37]. First, the posterosuperior prominence was resected endoscopically, then a suture anchor with 2 limbs was placed on the bone-resected site. Next, sutures were passed through the Achilles tendon using the shuttle relay technique and sutured subcutaneously at the stab wound.

Maquirriain[38] reported in a technical note that after the posterosuperior prominence resection, the partially detached Achilles tendon insertion was reattached to the surface of bone-resected calcaneus using a percutaneous absorbable screw[38].

Hegewald et al[39] reported in a technical note that they made three stab wounds on the medial margin of the Achilles tendon and three stab wounds on the lateral margin, sutured the Achilles tendon using a modified Bunnell technique, and finally fixed the sutures to the calcaneus with interference screws[39].

The following three technical notes demonstrated the sequence of exostosis resection at the Achilles tendon insertion, excision of the posterosuperior calcaneal prominence, and reattachment using anchors[40-42]. Debridement of the degenerated Achilles tendon was not performed. Boniface and Vervoort[40] presented the following procedure. First, two proximal portals (medial and lateral) for posterosuperior prominence resection and three distal portals (medial, lateral, and median) for exostosis resection were created. Next, a working space was created between the skin and the Achilles tendon, and exostosis resection, detachment of the middle portion of the Achilles tendon insertion, and posterosuperior prominence resection were performed endoscopically. Finally, the detached middle portion of the Achilles tendon was then reattached to the bone-resected surface with two rows of speed bridges. When this technique was performed with 10 cadavers, it required 120 min the first time and 70 min the last time. The method presented by Miller et al[41] is almost identical to that of Boniface and Vervoort, except that the Achilles insertion was totally detached in the former method[41]. Lopes et al’s method differs from that of the two previous studies in that the sutures were placed in the tendon[42]. Six portals were created on the medial and lateral margins of the Achilles tendon. After the posterosuperior prominence was resected endoscopically, the Achilles tendon was fixed with two rows of suture anchors that placed the two sutures in the tendon in S-shapes using the six portals.

Endoscopic augmentation using FHL tendon transfer

Hunt et al[17] reported a prospective comparative study that revealed no difference in clinical outcomes between procedures with and without FHL tendon transfer[18]; however, FHL tendon transfer was traditionally performed in cases where more than 50% of Achilles tendon insertion was released[7,10,11,15,17,18,27,43]. The advantage of the FHL transfer for Achilles tendon augmentation is that both tendons act in the same walking cycle phase[44]. In addition, studies have reported no loss of function of the hallux due to FHL transfer. Coull et al[45] reported that the patients’ hallux after FHL tendon transfer achieved the highest AOFAS score and that functional weakness of the hallux was not observed in daily living[45]. Hahn et al[46] observed that the FHL tendon was well integrated with the Achilles tendon on postoperative MRI, with ≥ 15% hypertrophy of the FHL muscle in 8 of 13 patients[46]. Other reported donors for augmentation include plantar tendon[6], sural triceps aponeurosis[47], and bone-patellar tendon[48].

A method for endoscopic FHL tendon harvest was published by Lui et al[49]. In this method, the FHL tendon was cut below the hallux’s interphalangeal joint, the interconnection tendon between the FHL and the flexor digitorum longus was dissociated using a tendon stripper, and the tendon was pulled out through a small skin incision at the Achilles tendon.

To the best of the current author’s knowledge, there are no reports of endoscopic Achilles tendon augmentation using the FHL transfer. However, if a technique to integrate the Achilles and harvested FHL tendons is developed, endoscopic FHL transfer will become possible.

Endoscopic posterosuperior calcaneal prominence resection

Several studies reported that posterosuperior prominence resection only for treating insertional Achilles tendinopathy had poor results[50-54]. Watson et al[50] reported that endoscopic posterosuperior prominence resection had a poor outcome in patients with calcaneal exostosis and recognized insertional Achilles tendinopathy and retrocalcaneal bursitis as different etiologies of posterior heel pain[50]. Leitze et al[51], Ortmann and McBryde[52], Jerosch[53], and Cusumano et al[54] excluded cases with severe insertional calcific Achilles tendinopathy for this endoscopic surgery[51-54]. Natarajan and Narayanan[55] reported that 8 out of 40 people with calcaneal exostosis who underwent endoscopic posterosuperior prominence resection would not recommend this procedure[55]. Kondreddi et al[56] reported that patients with Achilles tendon degeneration who underwent this surgery had lower subjective satisfaction[56]. However, Sundararajan and Wilde[57] reported that 5 of 20 patients with insertional Achilles tendinopathy presented with retrocalcaneal bursitis based on clinical and MRI findings[57]. Furthermore, a study by Rufai et al[58] observed that the periosteum of the posterosuperior prominence was replaced with fibrocartilage in cadavers with calcaneal exostosis[58], suggesting that insertional Achilles tendinopathy and posterior superior prominence pathology are not totally independent. Therefore, posterosuperior prominence resection should not be used alone for insertional Achilles tendinopathy but can be considered an option when needed.

Endoscopic posterosuperior prominence resection has been performed using two portals (medial and lateral)[59-62]. Wu et al[63] reported a case series of 27 patients whose three portals were effective. Van Sterkenburg et al[64] reported that the optimal endoscopic portal location varied with the shape of the posterosuperior prominence; thus, no index could be established. Lohrer et al[65] compared endoscopic and open osteotomy procedures using cadavers and reported similar rates of peroneal nerve injury and more bone fragments in the open osteotomy[65]. Roth et al[66] reported that endoscopic surgery resulted in less bone resection than open surgery, which they speculated may contribute to faster recovery[66]. Lui[67] reported that endoscopy in the supine position allowed for easier identification of anatomical structures than in the prone position[67]. Ferranti et al[68] reported that in 27 patients who underwent percutaneous posterosuperior prominence resection, the mean VISA-A score improved from 20 preoperatively to 75 postoperatively, and 84% experienced complete satisfaction[68].

Endoscopic gastrocnemius recession

To the best of the author’s knowledge, there is only one report on endoscopic gastrocnemius recession for treating insertional Achilles tendinopathy. Tallerico et al[69] followed up on 11 patients who underwent endoscopic gastrocnemius recession for an average of 13.8 mo. Ten of the 11 patients were highly satisfied, and the mean postoperative AOFAS score improved from 52.0 preoperatively to 94.8 postoperatively. Six of the 11 patients had calcaneal exostosis, and their AOFAS scores improved from 51.1 preoperatively to 91.9 postoperatively[69]. Gastrocnemius recession can also be a technique for reattaching the Achilles tendon. Gould reported 49 patients with insertional Achilles tendinopathy who underwent J-shaped skin incision, complete Achilles tendon detachment and debridement, posterosuperior prominence resection, and V-Y lengthening and reattachment[70]. Staggers et al[71] compared 25 patients who underwent V-Y lengthening of gastrocnemius and 21 who underwent FHL transplantation during open surgery for insertional Achilles tendinopathy and reported no significant difference in subjective satisfaction, VISA-A scores, and VAS scores between both groups[71].

ULTRASOUND-GUIDED SURGERY FOR INSERTIONAL ACHILLES TENDINOPATHY

Ultrasound-guided surgery also has the potential for minimally invasive surgery. However, Khan et al[72] reported that although MRI is effective in diagnosing insertional Achilles tendinopathy, ultrasound does not improve diagnostic accuracy[72]; thus, this surgery may be technically demanding for insertional Achilles tendinopathy.

Chimenti et al[73] reviewed 34 patients who underwent ultrasound-guided posterosuperior prominence resection, debridement of the Achilles tendon insertion and intra-tendinous calcifications, and retrocalcaneal bursectomy[73]. At 6-12 wk of follow-up, baseline pain decreased from 68% preoperatively to 5% postoperatively, with a satisfaction rate of 70%. In addition, four patients who were followed up for more than 11 mo were free of pain.

Wang et al[74] compared outcomes in 10 patients who underwent ultrasound-guided posterosuperior prominence resection and retrocalcaneal bursectomy and 12 who underwent open surgery[74]. The AOFAS scores at two years postoperatively were 95 in the open group and 94 in the minimally invasive group, with no significant difference.

Freed et al[75] performed ultrasound-guided Achilles fasciotomy and tenotomy in 26 people with insertional Achilles tendinopathy, with a mean operating time of 4 min and 32 s, a mean follow-up of 16 mo, and a success rate of 85%[75].

PERCUTANEOUS DORSAL WEDGE CALCANEAL OSTEOTOMY FOR INSERTIONAL ACHILLES TENDINOPATHY

Dorsal wedge calcaneal osteotomy for insertional Achilles tendinopathy has been frequently reported since 2010[76-85]. A closing wedge osteotomy of the calcaneus moves the Achilles tendon insertion upward and forward, loosening the Achilles tendon and widening the gap between the Achilles tendon and the posterosuperior prominence. In 1939, Zadek[86] first published a case series of three patients who underwent this osteotomy. Keck and Kelly[87] also published a 3-patient case series of similar osteotomy in 1965. Therefore, this osteotomy is sometimes called the Zadek osteotomy or the Keck and Kelly[87] osteotomy.

Good surgical results have been reported. Georgiannos et al[78] reviewed the outcomes of 52 athletes who underwent this osteotomy, with AOFAS scores improving from 59 to 95 and VISA-A scores improving from 65 to 90 at a minimum of three years of follow-up[78]. Maffulli et al[82] reported that in 25 patients who underwent this osteotomy, the median VISA-A score improved from 25 to 86, and 3 of 4 patients reported a return to the pre-injury state[82]. Cengiz and Karaoglu[85] followed up on 14 patients who underwent this surgery for more than three years. They reported that the AOFAS score improved from 56 preoperatively to 89 postoperatively, and the VAS score improved from 86 preoperatively to 41 postoperatively[85]. Ge et al[80] followed up on 12 patients who underwent this osteotomy for an average of 86 mo, with AOFAS scores improving from 52 to 98 and VISA-A scores improving from 37 to 98. They also reported that these postoperative scores were significantly higher than those of 32 patients who underwent posterosuperior prominence resection[80]. A description of this osteotomy technique was detailed in a review by Syed and Perera[77].

Recently, minimally invasive surgery for this osteotomy has been reported. Vernois et al[88] detailed this minimally invasive osteotomy technique using a 3-mm wide and 20-mm long Shannon bur[88]. Nordio et al[89] reported that in 26 patients who underwent percutaneous surgery, the Foot function index score improved from 65 to 8. The VAS score improved from 9 to 1, with a mean follow-up of 12 mo, and pain relief was achieved at a mean of 12 wk[89]. Choi and Suh[90] compared the outcomes of 11 patients who underwent minimally invasive osteotomy using a 2.2 mm Shannon bar and 14 patients who underwent open posterosuperior prominence resection. The VISA-A score of this osteotomy improved from 36 to 88, and the VAS score improved from 89 to 36. They also reported that minimally invasive surgery was significantly better than posterosuperior prominence resection at 6 mo postoperatively; however, the outcomes were similar at the final follow-up[90].

CONCLUSION

To establish minimally invasive surgery for insertional Achilles tendinopathy, the following four techniques must be minimally invasive: (1) Exostosis resection at the Achilles tendon insertion; (2) Debridement of degenerated Achilles tendon; (3) Reattachment using anchors or augmentation using FHL tendon transfer; and (4) Excision of the posterosuperior calcaneal prominence. This article reviewed studies from these four perspectives.

Exostosis resection at the Achilles tendon insertion was demonstrated in one case study, where blunt dissection around the exostosis was performed under fluoroscopy, an abrasion bur was introduced into the space created, and the exostosis was resected under fluoroscopic guidance.

Debridement of degenerated Achilles tendon was demonstrated in the same case study, where the space left after resection of the exostosis was an endoscopic working space, and the degenerated Achilles tendon and intra-tendinous calcification were debrided endoscopically.

Achilles tendon reattachment techniques have been demonstrated in several studies, where anchors were placed on the calcaneal surface after the posterosuperior prominence resection, and sutures were passed through the Achilles tendon using several stab wounds and fixated to the anchors.

In contrast, FHL tendon transfer techniques have not yet been published. The minimally invasive FHL harvest was reported in a technical note. Therefore, if a technique to integrate the Achilles tendon and the harvested FHL tendon is developed, endoscopic FHL transfer will become possible.

Endoscopic posterior superior prominence resection has already been established.

As with other minimally invasive surgeries for insertional Achilles tendinopathy, several studies on ultrasound-guided surgery and percutaneous dorsal wedge calcaneal osteotomy have been published.