Level of Evidence for the Treatment of Chronic Noninsertional Achilles Tendinopathy

Levels I to III

The highest-quality study examining the outcome of open debridement was 1 level II single-blinded RCT (Table 2). Morrison et al ¹¹ produced an RCT where patients received either radiofrequency microdebridement or traditional surgical decompression. The mean age in the surgical decompression group was 47 years, whereas the mean age in the radiofrequency group was 48 years. No high-level athletes were enrolled in the study. Both the microdebridement (n = 20) and open (n = 16) groups had a statistically significant improvement in VAS and VISA-A scores; however, no difference was found between treatment modalities at 6 months.

In a case-control, level III study, Maffulli et al ¹² investigated excision and debridement in age-matched men (n = 45) and women (n = 41). Both recreational athletes and sedentary individuals were included. The male cohort had significantly fewer complications, higher proportion of satisfied patients, and more marked improvement in VISA-A scores than the female cohort. Both cohorts had improved VISA-A scores postoperatively.

Levels IV and V

There were 8 level IV studies identified that reviewed open debridement (Table 3). The majority of the studies had a population of recreational or competitive athletes with a mean age in the 40s. The rates of a satisfactory treatment outcome ranged from 73.1% (19/26) to 100% (37/37). Furthermore, 4 of the studies reported a statistically significant improvement in their measuring scales for pain, function, and activity level.^13-16 Visual Analog Scale (VAS) pain scores decreased significantly following treatment in these 3 studies. Moreover, in one of these studies, the modified American College of Foot and Ankle Surgeons scores showed significant improvement following treatment, though the complication rate in this study was high (28.6%) because of inclusion of minor complications in the total rate. ¹⁵ Complications included deep-venous thrombosis (1%), superficial infection (4%), suture reactions (13%), and hypertrophic scarring (8%).

Grade of Recommendation

Based on the previously mentioned literature, the operative procedure of open debridement is assigned a grade B recommendation (fair evidence, level II or III studies with consistent findings), supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. Open debridement procedures were shown to provide promising results overall in terms of patient satisfaction, pain level, and/or tendon functionality.

Levels I to III

There were 3 level II studies investigating arthroscopic or minimally invasive surgical techniques as treatment for chronic noninsertional Achilles tendinopathy (Table 4). Alfredson ¹⁷ conducted a randomized trial comparing ultrasound and Doppler-guided mini-open surgery (n = 15) with percutaneous scraping (n = 16). The average follow-up was 18 months. Both groups had a statistically significant improvement in VAS postoperatively, and there were no differences between groups at final follow up.

Morrison et al ¹¹ produced an RCT where patients received either radiofrequency microdebridement or traditional surgical decompression in a mixed active, athletic and sedentary population. Both the microdebridement (n = 20) and open (n = 16) groups had a statistically significant improvement in VAS and VISA-A scores; however, no difference was found between treatment modalities at 6 months. The authors reported no significant differences in the results between open treatment and percutaneous treatment.

Alfredson et al ¹⁸ conducted a randomized trial comparing active patients treated with sclerosing polidocanol injections (n = 9) with open surgical revision of the area with vasculo/neural ingrowth on the ventral side of the Achilles tendon (n = 10). At the 6-month follow-up, 6 of 9 patients (66.7%) in the injection group and 8 of 10 patients in the release group (80%) were satisfied with the treatment and had a significantly reduced level of tendon pain. The injection group improved significantly from a preoperative VAS score of 76 to a postoperative score of 24 (P < .05); the release group also improved significantly from a preoperative VAS score of 75 to a postoperative score of 21 (P < .05). There were no statistically significant differences between the 2 groups.

Levels IV and V

There were 12 level IV studies identified that reviewed arthroscopic or minimally invasive surgical techniques (Table 5). Most studies (10 of 12) included a mixed or not reported population. The mean age of the participants was less than 40 years in 2 studies, in the 40s in 4 studies, and in the 50s in 6 studies. The rates of a good or excellent outcome ranged from a low of 72.4% (21/29) to 100% (24/24). A fairly low complication rate was noted as well, ranging from 0% (0/11) to 17.4% (4/23). Complications included superficial wound infections, deep venous thrombosis, hypertrophic scarring, delayed wound healing, and sural nerve injury. There were 5 instances of sural nerve palsies related to Minimally Invasive Surgery (MIS) Achilles tendon stripping out of 47 patients. ¹⁹ Most studies (10 of 12) also demonstrated statistically significant improvement in pain and/or function.

Grade of Recommendation

Based on the previously mentioned literature, arthroscopic or minimally invasive surgical techniques are assigned a grade B recommendation (fair evidence, level II or III studies with consistent findings), supporting them as an effective treatment for chronic noninsertional Achilles tendinopathy. Minimally invasive techniques were shown to provide promising results overall in terms of patient satisfaction, pain level, and/or tendon functionality, with minimal complications.

Levels IV and V

There were 9 level IV studies identified that reviewed FHL transfer (Table 6). Only 3 studies reported the population studied; 2 of these included only sedentary patients, whereas the third included both recreational athletes and sedentary patients. The mean age of patients tended to be older in the studies of this treatment, with 3 in the 40s, 3 in the 50s, and 3 in the 60s. The rates of a satisfactory treatment outcome ranged from 75% (15/20) to 95.2% (59/62). However, a relatively high complication rate was reported in these studies, ranging from 0% (0/23) to 39% (7/18). Complications included delayed wound healing, hypertrophic or sensitive scars, deep vein thrombosis, superficial infection, and deep peroneal nerve palsy. All 9 studies showed either improvement in pain or tendon functionality or a good-to-excellent subjective patient outcome following treatment. Furthermore, 3 of the studies reported a statistically significant improvement in pain, function, and activity level.^20-22 In the Schon et al ²³ study, the VAS pain scores and the Ankle Osteoarthritis Scale pain scores decreased a statistically significant amount, and the 36-Item Short Form Survey scores increased a statistically significant amount following FHL transfer. However, a fairly high number of complications (27.1%) were reported. In this study, 2 patients had deep vein thrombosis, 6 had superficial infection or delayed wound healing, and 4 had scar pain. In Wegrzyn et al, ²² the American Orthopaedic Foot and Ankle Scores (AOFAS) increased a statistically significant amount following FHL transfer. The sample size of this study was small, but no major complications with regard to wound healing were noted.

Grade of Recommendation

Based on the previously mentioned literature, the operative procedure of FHL transfer is assigned a grade C recommendation (poor evidence, level IV or V studies with consistent findings) supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. It should be noted, however, that the FHL transfer procedure was shown to provide promising results overall in terms of patient satisfaction, pain level, and/or tendon functionality and may warrant a level II to III study in the future that would better define the outcome and evidence for such a surgical intervention.

Levels I to III

One level II study and 2 level III studies investigated longitudinal tenotomy as treatment for chronic noninsertional Achilles tendinopathy (Table 7). Benazzo et al ²⁴ prospectively compared athletes who were treated with longitudinal tenotomies (n = 20) and those who underwent soleus fiber transfer (n = 32). Both groups had significantly improved AOFAS and VISA-A scores postoperatively, although the soleus fiber transfer had a statistically significantly greater increase compared to the longitudinal tenotomy group. The soleus fiber transfer group also had a shorter return to run without pain (98.9 compared with 122.2 days). This was a medium follow-up study with final outcomes measured at 4 years.

Maffulli et al ¹² conducted a case-control study of multiple longitudinal tenotomy and debridement treatments in athletes (n = 45) compared to nonathletes (n = 48). The follow-up for this study was 37 months. The authors stated that there was no significant difference between the 2 study groups in their VISA-A scores preoperatively or postoperatively, but all patients showed significant improvement after surgery. The VISA-A scores of the athlete group improved from 53.5 preoperatively to 88.5 postoperatively, and the VISA-A scores of the nonathlete group improved from 55 preoperatively to 74.2 postoperatively. The nonathlete group had a lower satisfaction level (33/48 patients indicated a satisfactory outcome, or 68.8%) compared with the athlete group (42/45 patients indicated a satisfactory outcome, or 93.3%), likely as a result of the higher rate of complications in the nonathlete group (50%) compared with the athlete group (8.9%).

Bohu et al ²⁵ retrospectively compared longitudinal tenotomy and debridement in a group with insertional Achilles tendinopathy (n = 38) with a group with noninsertional Achilles tendinopathy (n = 82). The average follow-up for this study was 38 months, though the range of follow-up was quite large, spanning 7 to 98 months. The noninsertional group indicated a high satisfaction with the treatment outcome, with 74 of 82 patients (90.2%) indicating a good or excellent postoperative outcome.

Level IV

There were 6 level IV studies identified that reviewed longitudinal tenotomy (Table 8). Three studies included athletic populations, 2 studies had mixed populations, and 1 study did not report the activity level of the population. The mean age of patients was in the 20s in 1 study, 30s in 4 studies, and 40s in 1 study. The rates of a satisfactory treatment outcome ranged from 77.1% (37/48) to 100% (8/8). Few major complications were noted other than in the study by Maffulli et al, ¹² which had a complication rate of 10%. Complications included superficial infections that responded to oral antibiotics, scar hypersensitivity, and hypertrophic scarring, and all responded to treatment.

Grade of Recommendation

Based on the previously mentioned literature, the operative procedure of longitudinal tenotomy is assigned a grade C recommendation (poor evidence, level IV or V studies with consistent findings), supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. The single level II study showed soleus fiber transfer to confer a greater increase in AOFAS and VISA-A scores compared with longitudinal tenotomy, although both groups had improved scores postoperatively. The 2 level III studies did not demonstrate longitudinal tenotomy to be superior to other operative interventions, though they did show good results for patients treated with longitudinal tenotomy. Longitudinal tenotomy procedure was shown in all studies to provide promising results overall in terms of patient satisfaction with the outcome.

Levels I to III

The highest-quality study examining the outcome of peritenolysis was 1 level II study (Table 9). Paavola et al ²⁶ carried out a prospective study (level II) comparing peritenolysis (n = 16) with peritenolysis with debridement (n = 26), with a follow-up at 7 months. This was comparing the surgery for patients with intratendinous lesions (peritenolysis with debridement) with those with only peritendinous involvement (peritenolysis). They found that there was no significant difference in symptoms outcome between groups; however, the peritenolysis had significantly higher performance scores at final follow-up compared to the peritenolysis and debridement group. At the 7-month follow-up, all 16 patients in the peritenolysis group stated that they were satisfied with their treatment outcome, compared with 19 of 26 patients in the peritenolysis with debridement group. Peritenolysis alone had fewer complications as well.

Levels IV and V

There were 2 level IV studies identified that reviewed peritenolysis (Table 10). Saxena et al ²⁷ prospectively examined primarily runners with a mean age in their 40s who underwent either debridement for tendinosis (n = 59) or peritenolysis for paratendinosis or tendinosis (n = 48). The mean return to activity was shorter for the peritenolysis group. Both groups had very favorable results, with 96% good or excellent results in the peritenolysis group and 98% in the debridement group.

Schepsis and Leach ²¹ retrospectively reviewed competitive runners with a mean age of 29 years with Achilles tendinopathy treated surgically. In the noninsertional subgroup, patients were treated with peritenolysis ± debridement. In all, 15/24 patients returned to their previous level of activity, and 22/24 patients had good or excellent outcomes.

Grade of Recommendation

Based on the previously mentioned literature, the operative procedure of longitudinal tenotomy is assigned a grade C recommendation (poor evidence, level IV or V studies with consistent findings), supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. All 3 studies identified that reviewed peritenolysis demonstrated good results for patients treated with peritenolysis. Although there were level II and III studies in support of peritenolysis, the number of studies addressing peritenolysis was minimal overall, thereby preventing a higher recommendation.

Levels IV and V

There were 4 level IV studies identified that reviewed gastrocnemius recession (Table 11). No studies reported the activity level of their population. Three studies had a mean age in the 40s, and 1 study had a mean age in the 50s. The rates of a satisfactory outcome ranged from 92.9% (16/17) to 100% (8/8). All 4 studies demonstrated statistically significant improvement in ankle pain and functionality, as measured by AOFAS, Foot Function Index, VAS, and/or VISA-A. A range of complications was reported, from 0% in 2 studies to 40% in 1 study.^28-30 It should be noted that this study only had 5 patients. ²⁹

Grade of Recommendation

Based on the previously mentioned literature, the operative procedure of gastrocnemius recession is assigned a grade C recommendation (poor evidence, level IV or V studies with consistent findings), supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. Although the number of available studies on gastrocnemius recession was minimal, it should be noted that gastrocnemius recession was shown to provide promising results overall in terms of patient satisfaction, pain level, and/or tendon functionality, with minimal complications. A larger higher-level study is warranted.

Level IV

There were 4 level IV studies that examined excision of the plantaris tendon ± paratendinous scraping (Table 12). Jowett et al ³¹ looked at paratendinous scraping and excision of plantaris in recreational athletes (n = 19) and sedentary patients (n = 7) in their 40s. There was a statistically significant improvement in VISA-A scores and an 84% satisfaction rate in the recreational athlete group. There was a slightly lower satisfaction rate of 78% in the sedentary group; this was not compared with the recreational athlete group, so its statistical significance is unknown. VISA-A scores were not reported in the sedentary group.

Bedi et al ³² prospectively examined plantaris excision and peritendinous scraping in 15 professional or semiprofessional athletes with a mean age of 32 years. There was a significant improvement in the VISA-A score, and 14/15 (93%) had satisfactory results. Additionally, there was a statistically significant improvement in the aligned fibrillar structure of the Achilles tendon confirmed with UTC scanning postoperatively.

Calder et al ³³ studied 16 competitive and recreational athletes with a mean age of 26 years who underwent plantaris excision. There was statistically significant improvement in mean VAS scores and all domains of the Foot and Ankle Outcome Scale (FAOS) postoperatively. The excised tendon was found to be histologically normal in 13/16 cases (81%), but inflammatory changes in the peritendinous connective tissue was evident in all cases.

Calder et al ³⁴ prospectively examined plantaris tendon excision in 32 elite athletes with a mean age of 27 years. There was a significant improvement in VAS and all domains of the FAOS; 90% of athletes reported a satisfactory outcome and 94% returned to sport.

Grade of Recommendation

Based on the previously mentioned literature, plantaris tendon excision is assigned a grade C recommendation (poor evidence, level IV or V studies with consistent findings) supporting it as an effective treatment for chronic noninsertional Achilles tendinopathy. Plantaris tendon excision was shown to provide promising results overall in terms of patient satisfaction, pain level, and/or tendon functionality, with minimal complications.

Level IV

There were 5 level IV studies identified that reviewed other surgical treatment methods for chronic noninsertional Achilles tendinopathy (Table 13). These methods were FDL tendon transfer, ³⁵ medial head of gastrocnemius release, ³⁶ peroneus brevis tendon transfer, ³⁷ plantaris stripping and release, ³⁸ Z-plasty tendon lengthening, ³⁹ and debridement with tendon flap. ⁴⁰ The 5 techniques demonstrated a postoperative satisfaction rate ranging from 81.3% (13/16) to 100% (3/3). Furthermore, 4 of the studies reported a statistically significant improvement in pain, function, and activity level.^35,36,38,39 In van Sterkenburg et al, ³⁸ the VAS pain scores decreased significantly following plantaris stripping and release, and VISA-A scores increased significantly postoperatively. In Costa et al, ³⁹ results following tendon lengthening showed a long-term (7.5 years) reduction in VAS scores for sporting activity in 20 of the 21 procedures performed (P < .0005), which suggests excellent long-term reduction of Achilles pain after tendon lengthening. However, a high complication rate (23.8%) was reported with this treatment. There was 1 instance of deep vein thrombosis and pulmonary embolus, 1 instance of superficial infection, 1 keloid scar, 1 minor skin adhesion, and 1 postoperative sural nerve palsy.

Grade of Recommendation

There is insufficient evidence to assign a grade of recommendation for FDL tendon transfer, release of medial head of gastrocnemius, peroneus brevis tendon transfer, plantaris stripping and release, Z-plasty lengthening, or debridement with tendon flap for noninsertional Achilles tendinopathy.