Endoscopic Flexor Hallucis Longus Transfer for Achilles Noninsertional Tendinopathy: Description of Surgical Technique and Functional Outcomes

Abstract

Background. The transfer of the flexor hallucis longus (FHL) tendon is an established treatment for replacing a dysfunctional Achilles tendon. Objectives. (1) Describe a new technique for endoscopic FHL transfer for noninsertional Achilles tendinopathy and (2) describe the functional outcomes and complications after endoscopic and open FHL transfer. Materials and Method. Retrospective study of patients who underwent open or endoscopic FHL transfer between 2014 and 2016. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle/hindfoot scale was used preoperatively and postoperatively to measure the functional results. Results. We included 18 endoscopic FHL transfers and 24 open FHL transfers. The mean age of endoscopic and open procedures was 47.5 years (range 25-77 years) and 61.2 years (range 43-72 years), respectively. An improvement on the average AOFAS of 52.8% (31.9 points) was observed in the endoscopy group during the follow-up from the baseline. The mean improvement in AOFAS score for the open group was 41.4% (24.5 points). Four and 7 cases reported complications in the endoscopy and open FHL transfer groups, respectively. Conclusion. While both procedures were effective in treating noninsertional Achilles tendinopathy, the described arthroscopic treatment led to a greater improvement in the AOFAS score and is slightly less prone to lasting complications. Level of Evidence: Level IV: Case series

Level of Evidence for the Treatment of Chronic Noninsertional Achilles Tendinopathy

“…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.…”

ICON 2020—International Scientific Tendinopathy Symposium Consensus: A Systematic Review of Outcome Measures Reported in Clinical Trials of Achilles Tendinopathy

“…2). This core domain included measures relating to return to activity, including sports (18 studies) [14,19,22,87,98, [169,258,275,284]. The most commonly reported measurement instrument was the Tegner Score (five studies) [13,111,121,205,308].…”

“…'Clinical examination findings' included various measures such as swelling (five studies) [14,18,45,137,284] and calf circumference (four studies) [197,200,212,216].…”