Plantarflexion Torque Following Reconstruction of Achilles Tendinosis or Rupture with Flexor Hallucis Longus Augmentation

Abstract

Nine patients treated surgically for Achilles tendon rupture (7 patients) or tendinosis (2 patients) with primary repair or debridement and augmentation with the flexor hallucis longus muscle-tendon unit were evaluated at a mean of 19 months postoperative. Subjective evaluation revealed a high level of satisfaction. All patients returned to work and only two patients reported limitation in their recreational activities. The mean post-operative AOFAS Ankle-Hindfoot Score was 90 points. Four patients reported mild occasional pain and one patient complained of moderate daily pain. Motion assessment showed a 20% increase in the hallux MTP dorsiflexion compared to the non-operative side (p = 0.045). No difference in ankle motion was noted. Cybex II+ dynamic evaluation of plantarflexion peak torque was complete on both extremities. The torque deficit on the reconstructed extremity was 20% (p = 0.01) at 120 degrees per second and 26% (p = 0.003) at 30 degrees per second. There is no significant difference between the torque deficit recorded for patients with Achilles rupture and those with Achilles tendinosis. A trend toward improved torque production with longer follow up was observed.

Hypertrophy of the flexor hallucis longus muscle after tendon transfer in patients with chronic Achilles tendon rupture

“…In the study of Wegrzyn et al [8] the postoperative deficit in plantar flexion torque averaged 28%, and 41% in the study of Wapner et al [4]. Interestingly, in studies where FHLT transfer was performed mainly due to the chronic Achilles tendinopathy, the deficits in plantar flexion strength have been of similar magnitude; 35% in the study of Hahn et al [5] and 28% in the study of Monroe et al [10]. Making far-reaching conclusions of the strength measurements between studies is difficult due to the small patient series, different time from operation to measurements, and large variation between patients due to their age and physical demands.…”

“…These studies also show very low failure rates after the FHLT transfer [4][5][6][7][9][10][11][12][13].…”

“…Several small patient series have shown good results with FHLT transfer [4][5][6][7][8][9][10][11][12]. The previous results have shown that the plantar flexion strength of the operated side cannot be fully restored, but most of the patients have been able to re-enter their previous sports interests.…”

“…Flexor hallucis longus tendon (FHLT) transfer has become a popular method for reconstructing a chronic ATR [4][5][6][7][8][9][10][11][12]. This method has many advantages.…”

Chronic Achilles tendon rupture reconstruction using a modified flexor hallucis longus transfer

“…In a recent study, Hahn et al found a plantar flexion peak torque deficit of 35% at 60 deg/sec in a cohort of 13 patients including ten chronic AT ruptures and three tendinopathies at an average followup of 46.5 months [9]. Two other studies in the literature included both chronic rupture and Achilles tendinosis and had some limitations [18,27]. Monroe et al also recorded a 28% peak torque deficit at 30 deg/sec [18].…”